 fuel cell system and control method for the same
专利摘要:
fuel cell system and control method for the same. a fuel cell system and a control method for it are provided. the fuel cell system (100) includes: a fuel cell (10) formed from a plurality of stacked power generating elements (11); a cell voltage measuring unit (91) detecting negative voltage in any of the power generating elements (11); a control unit (20) controlling the production of the electric force of the fuel cell (10) and a unit of measurement of the accumulated current value (21) measuring the cumulative current value obtained by the time integration of the cell current population of fuel. control unit (20) pre-stores a correlation between accumulated current values and current densities that are allowable for fuel cell (10) during a period during which negative voltage is generated. When negative voltage is detected, the control unit (20) performs the production restriction process to restrict the production of the electric force of the fuel cell (10) so as to fall within a permissible operating range defined by the values. current values and correlation current densities. 公开号:BR112012030022B1 申请号:R112012030022-9 申请日:2011-05-25 公开日:2019-11-19 发明作者:Kumei Hideyuki；Kato Manabu；Kawahara Shuya 申请人:Toyota Motor Co Ltd； IPC主号:
专利说明:
“FUEL CELL SYSTEM AND METHOD OF CONTROL FOR THE SAME” Precedents of the invention 1. Field of the invention The invention relates to a fuel cell. 2. Description of the related technique A fuel cell generally has a stack structure in which a plurality of single cells are stacked that serve as power generating elements. Reaction gases flow into the gas flow passages, supplied to each single cell, through respective distribution tubes and are supplied to a force generating portion of each single cell. However, if the gas flow passages of part of the single cells are blocked by the frozen water content, or the like, the quantities of reaction gases supplied to the part of the single cells become insufficient, so that the part of the single cells can possibly generate ten15 are negative. Thus, when fuel cell operation continues in a - state where part of the single cells generates negative voltage, not only does the power generation performance of the fuel cell in general deteriorate, but also the electrodes of these single cells can degrade possibly. Various techniques for suppressing deterioration in the power generation performance of a fuel cell or degradation of a fuel cell 20 due to such negative stress have been suggested so far (see Japanese Patent Application Publication No. 2006-179389 (JP- A-2006-179389), Publication of Japanese Patent Application No. 2007-035516 (JP-A-2007-035516) and so on). Summary of the invention The invention provides a technique for suppressing deterioration in performance and degradation of a fuel cell due to negative voltage. The invention is considered to solve at least part of the problems described above, and can be carried out as the following modalities or alternative modalities. One aspect of the invention provides a fuel cell system that produces the electrical force generated in response to a request for an external charge. The fuel cell system includes: a fuel cell that has at least one power generating element; a negative voltage detection unit that is configured to detect negative voltage in at least one power generating element; a control unit that is configured to control the production of electrical power from the fuel cell and a unit of measurement of the accumulated current value that is configured to measure an accumulated current value that is obtained by integration in the production time 2/44 fuel cell current, where the control unit is configured to pre-store a correlation between accumulated current values that are permissible in a period during which negative voltage is generated in at least one power generating element and current densities that are permissible in the period and, when the negative voltage is detected in at least one power generation element, the control unit is configured to perform the production restriction process to restrict the production of the electrical power of the cell of fuel, in order to fall within a permissible operating range defined by the cumulative permissible current values and permissible current densities of the correlation. Here, the inventors of the invention have found that, in a force generating element in which negative voltage is generated, the regulation in which the electrode oxidation begins and the power generation performance begins to decrease can be defined by the current production of the fuel cell in a period during which the negative voltage is generated and an accumulated current value that is obtained by integrating the current time. With the fuel cell system so configured, where negative voltage is generated, the production of electrical power from the fuel cell is restricted so that it falls within the allowable range of pre-established operation defined by the cumulative allowable current values and the densities of allowable currents. Thus, by presetting the permissible operating range that does not cause deterioration in the performance of the power generating element in which the negative voltage is generated, it is possible to suppress the deterioration in the performance of the fuel cell due to the negative voltage and suppress the oxidation of the electrode (electrode degradation). In addition, in the fuel cell system, when the correlation is shown by a graph of which a first geometry axis represents an accumulated current value of the fuel cell and a second geometry axis represents the current density of the fuel cell, the correlation can be shown as a downward convex curve in which the allowable current density decreases as the cumulative allowable current value increases. With the above fuel cell system, in the correlation between accumulated current values and current densities, stored in the control unit, the permissible operating range can be adjusted to an appropriate range that does not cause deterioration in the performance of the generating element. force in which negative tension is generated. Thus, it is also possible to properly suppress performance deterioration and fuel cell degradation due to negative voltage. In addition, in the fuel cell system, in the production restriction process, the control unit can be configured to decrease the current density of the fuel cell along the downward convex curve, which indicates maximum allowable current densities , with an increase in the accumulated current value. 3/44 With the above fuel cell system, when the negative voltage is generated, it is possible to restrict the production of the electrical power of the fuel cell over the threshold values (allowable limit values) of the allowable operating range. Thus, it is possible to suppress performance deterioration and degradation of the fuel cell due to the negative voltage while suppressing excessive restrictions on the production of the electric force of the fuel cell. In addition, the fuel cell system may further include: an operating state regulation unit that is configured to include at least one of a humidification unit that controls the amount of humidification of the reaction gas supplied to the fuel cell in order to regulate the wet state inside the fuel cell and a refrigerant supply unit that controls the flow rate of the refrigerant supplied to the fuel cell in order to regulate the operating temperature of the fuel cell, and a refrigeration unit correlation change which is configured to change the correlation in response to at least one of the wet state within the fuel cell and the operating temperature of the fuel cell, where, when the current density corresponds to a required production current of the external load in a period during which the negative voltage is generated in at least one element power generation is greater than a predetermined value, the control unit can be configured to cause the operating state regulation unit to regulate at least one of the wet state within the fuel cell and the operating temperature of the cell of fuel in order to expand the permissible operating range in such a way that the correlation is altered by the correlation change unit. Here, the correlation between accumulated current values and current densities that are permissible for the fuel cell in a period during which the negative voltage is generated varies depending on the wet state within the fuel cell or the operating temperature of the fuel cell. fuel. With the fuel cell system so configured, even when the current required for the fuel cell falls outside the permissible operating range of the fuel cell, the required current can be brought into the permissible operating range in such a way that at minus one of the wet state within the fuel cell and the operating temperature of the fuel cell is regulated to expand the permissible operating range. In addition, in the fuel cell system, when the production restriction process is complete, the control unit can be configured to store a non-volatile accumulated current value from the fuel cell current production in the restriction process. and, when the production restraint process is resumed, the control unit can be configured to perform the production restraint process using a total accumulated current value that is obtained 4/44 by adding the accumulated stored current value and an accumulated current value from the fuel cell current production after the production restraint process is resumed. With the above fuel cell system, the accumulated current value is recorded even after a restart of the fuel cell system. Therefore, even when the current restriction process is performed again after a restart of the fuel cell system, the current restriction process is performed using the total accumulated current value that is accumulated according to the recorded accumulated current value. In addition, the fuel cell system can also include a warning unit that is configured to warn a user about fuel cell degradation, where the control unit can be configured to pre-store a lower density limit value current of the fuel cell and, when the current density of the fuel cell is lower than the lower limit value in the production restriction process, the control unit can be configured to cause the warning unit to notify the user about fuel cell degradation. With the above fuel cell system, when the fuel cell has not recovered from the negative voltage, but the preset lower limit value of the current density of the fuel cell has been reached during the production restriction process, the user is warned about fuel cell degradation. Thus, the user is able to properly know the regulation in which the fuel cell must be maintained. In addition, the fuel cell system may further include: a refrigerant supply unit that is configured to supply refrigerant to the fuel cell to control the temperature of the fuel cell and a temperature measurement unit that is configured to measure the operating temperature of the fuel cell, in which, in the process of production restriction, the control unit can be configured to obtain an estimated thermal value which is a thermal value of the fuel cell when the fuel cell is induced to produce the electrical force at a current density based on a current density command value for the fuel cell, and control the amount of refrigerant supplied to the fuel cell by the refrigerant supply unit based on the operating temperature measured by temperature measurement unit and the estimated thermal value. With the above fuel cell system, even when the production of the electric power of the fuel cell is restricted by performing the production restriction process, the flow rate of the filled refrigerant is properly controlled, so the increase in the operating temperature of the fuel cell while the production restriction process is performed is made easier. Thus, it is highly likely that the fuel cell will 5/44 recover from the negative voltage state. In the fuel cell system, in the production restriction process, the control unit can be configured to use the estimated thermal value and the operating temperature measured by the temperature measurement unit to calculate an estimated temperature rise in the fuel cell when the fuel cell is induced to produce electrical power for a predetermined period of time while the fuel cell is being supplied with refrigerant and, when the estimated temperature rise is less than or equal to a pre-established threshold, the unit of control can be configured to make the fuel cell generate electrical power in a state where the refrigerant supply unit is induced to stop supplying the refrigerant to the fuel cell. With the above fuel cell system, when it is difficult to bring the fuel cell operating temperature to a target value because the production of the electric power of the fuel cell is restricted through the production restriction process, the supply of refrigerant to the fuel cell is stopped. Thus, an increase in the temperature of the fuel cell while the production restriction process is carried out is facilitated, so that it is highly likely that the fuel cell will recover from the negative voltage state. In addition, in the fuel cell system, in the production restriction process, when the rate of increase in the fuel cell operating temperature is less than a pre-established threshold, the control unit can be configured to make the fuel cell fuel generates electrical power in the state where the refrigerant supply unit is induced to stop supplying the refrigerant to the fuel cell. With the above fuel cell fuel system, when the rate of increase in the fuel cell temperature has not reached a target value according to the actual measured operating temperature of the fuel cell while the production restriction process is carried out , the refrigerant supply to the fuel cell is stopped. Thus, an increase in the temperature of the fuel cell while the production restriction process is carried out is facilitated, so it is highly likely that the fuel cell will recover from the negative voltage state. Another aspect of the invention provides a control method for a fuel cell system that produces electrical power generated by a fuel cell having at least one power generating element in response to a request for an external load. The control method includes: detecting the negative voltage in at least one force generating element; measure the accumulated current value that is obtained by integrating the fuel cell current production over a period during which the negative voltage is generated in at least one power generating element; consult a pre-established correlation between accumulated current values that are permissible in the 6/44 period during which the negative voltage is generated in at least one power generation element and current densities that are permissible in the period and perform the production restriction process to restrict the production of the electric power of the fuel cell, so as to fall within a permissible operating range defined by the cumulative permissible current values and permissible current densities of the correlation. Another additional aspect of the invention provides a fuel cell system that produces electrical power generated in response to a request for an external load. The fuel cell system includes: a fuel cell that has at least one power generating element; a control unit that is configured to control the production of the electric power of the fuel cell and a unit of measurement of accumulated current value that is configured to measure the accumulated value of current that is obtained by the integration in time of the current production of the fuel cell, in which the control unit is configured to pre-store a correlation between accumulated current values that are permissible in a period during which negative voltage is generated in at least one power generation element and current densities that are permissible in the period and, when a pre-established environmental condition that indicates a possibility that the negative voltage is generated is satisfied, the control unit is configured to determine that the negative voltage is generated in at least one power generation element and then execute the production restriction process to restrict the production of the force electrical power of the fuel cell, so that it falls within a permissible operating range defined by the cumulative permissible current values and permissible current densities of the correlation. With the fuel cell system thus configured, even when negative voltage is not generated, but when an environmental condition that is assumed empirically or experimentally as the case where negative voltage is highly likely to be generated, the production restriction process runs. Thus, it is also possible to safely suppress performance deterioration and fuel cell degradation. In addition, in the fuel cell system, when the correlation is shown by a graph of which the first geometry axis represents an accumulated current value of the fuel cell and the second geometry axis represents the current density of the fuel cell, the The correlation can be shown as a downward convex curve in which the allowable current density decreases as the cumulative allowable current value increases. With the above fuel cell system, in the correlation between accumulated current values and current densities, stored in the control unit, the permissible operating range can be established in an appropriate range that does not cause deterioration in the performance of the generating element. force in which negative tension is generated. Thus, it is still possible to properly suppress the 7/44 performance deterioration and fuel cell degradation due to negative voltage. In addition, in the fuel cell system, in the production restriction process, the control unit can be configured to decrease the current density of the fuel cell along the downward convex curve, which indicates maximum values for current densities permissible, with an increase in the accumulated current value. With the above fuel cell system, when negative voltage is generated, it is possible to restrict the production of the fuel cell's electrical force over the permissible limit values of the permissible operating range. Thus, it is possible to suppress performance deterioration and degradation of the fuel cell due to the negative voltage while suppressing excessive restrictions on the production of the electric force of the fuel cell. In addition, the fuel cell system may further include: an operating state regulation unit that is configured to include at least one of a humidification unit that controls the amount of humidification of the reaction gas supplied to the fuel cell in order to regulate the wet state inside the fuel cell and a refrigerant supply unit that controls the flow rate of the refrigerant supplied to the fuel cell in order to regulate the operating temperature of the fuel cell and a change unit correlation that is configured to change the correlation in response to at least one of the wet state within the fuel cell and the operating temperature of the fuel cell, where, when the current density corresponds to a required production current of the load in a period during which negative voltage is generated in at least one element power generation is greater than a predetermined value, the control unit can be configured to make the regulating unit regulating the regular operating state at least one of the wet state within the fuel cell and the operating temperature of the fuel cell , in order to expand the permissible operating range in such a way that the correlation is altered by the correlation change unit. With the above fuel cell system, even when the current required for the fuel cell falls outside the fuel cell's permissible operating range, the required current can fall within the permissible operating range in such a way that at least one of the wet state within the fuel cell and the fuel cell operating temperature is regulated to expand the permissible operating range. In addition, in the fuel cell system, when the production restriction process is complete, the control unit can be configured to store a non-volatile accumulated current value from the fuel cell current production in the restriction process. production and, when the process of restricting 8/44 production is resumed, the control unit can be configured to perform the production restriction process using a total current accumulated value that is obtained by adding the stored current accumulated value and the current accumulated current production value of the fuel cell after the production restriction process is resumed. With the above fuel cell system, even when the current restriction process is performed again after restarting the fuel cell system, the current restriction process is performed using the total accumulated current value that is accumulated as per the accumulated recorded current value. In addition, the fuel cell system can also include a warning unit that is configured to warn a user about fuel cell degradation, where the control unit can be configured to pre-store a lower density limit value current of the fuel cell and, when the current density of the fuel cell is lower than the lower limit value in the production restriction process, the control unit can be configured to make the warning unit warn the user about the degradation of the fuel cell. With the above fuel cell system, when the fuel cell has not recovered from the negative voltage, but the preset lower limit value of the current density of the fuel cell has been reached during the production restriction process, the user is warned about fuel cell degradation. Thus, the user is able to properly know the regulation in which the fuel cell must be maintained. In addition, the fuel cell system may further include: a refrigerant supply unit that is configured to supply refrigerant to the fuel cell to control the temperature of the fuel cell and a temperature measurement unit that is configured to measure the operating temperature of the fuel cell, in which, in the process of production restriction, the control unit can be configured to obtain an estimated thermal value which is a thermal value of the fuel cell when the fuel cell is induced to produce power current density based on a current density control value for the fuel cell and control the amount of refrigerant supplied to the fuel cell by the refrigerant supply unit based on the operating temperature measured by the measuring unit temperature and the estimated thermal value. With the above fuel cell system, even when the production of electric power from the fuel cell is restricted by performing the production restriction process, the flow rate of the filled refrigerant is properly controlled, so an increase in the operating temperature of the fuel cell while the production restriction process is performed is made easier. Thus, it is highly likely that the fuel cell will recover from the negative voltage state. 9/44 In addition, in the fuel cell system, in the production restriction process, the control unit can be configured to use the estimated thermal value and the operating temperature measured by the temperature measurement unit to calculate an estimated temperature rise in the fuel cell when the fuel cell is induced to produce electrical power for a predetermined period of time while the fuel cell is being supplied with refrigerant and, when the estimated temperature rise is less than or equal to a pre-established threshold, the control unit can be configured to cause the fuel cell to generate electrical power in a state where the refrigerant supply unit is induced to stop supplying the refrigerant to the fuel cell. With the above fuel cell system, when it is difficult to bring the fuel cell operating temperature to a target value because the production of the electric power of the fuel cell is restricted through the production restriction process, the supply of refrigerant to the fuel cell is stopped. Thus, an increase in the temperature of the fuel cell while the production restriction process is carried out is facilitated, so that it is highly likely that the fuel cell will recover from the negative voltage state. In addition, in the fuel cell system, in the production restriction process, when the rate of increase in the fuel cell operating temperature is less than a pre-established threshold, the control unit can be configured to make the fuel cell fuel generates electrical power in the state where the refrigerant supply unit is induced to stop supplying the refrigerant to the fuel cell. With the above fuel cell fuel system, when the rate of increase in the fuel cell temperature has not reached a target value according to the measured operating temperature of the fuel cell while the production restriction process is performed, the supply of refrigerant to the fuel cell is stopped. Thus, an increase in the temperature of the fuel cell while the production restriction process is carried out is facilitated, so it is highly likely that the fuel cell will recover from the negative voltage state. Yet another aspect of the invention provides a control method for a fuel cell system that produces electrical power generated by a fuel cell having at least one power generating element in response to a request for an external load. The control method includes: measuring an accumulated current value that is obtained by integrating fuel cell current production over a period during which a pre-established environmental condition that indicates a possibility that the negative voltage will be generated at least an element of power generation is satisfied; consult a pre-established correlation between accumulated current values that are permissible in the period during which the negative voltage is generated at least 10/44 a power generation element and current densities that are permissible in the period and perform the production restriction process to restrict the production of the electric power of the fuel cell, so as to fall within a defined permissible operating range by the cumulative permissible current values and permissible current densities of the correlation. Note that aspects of the invention can be performed in several ways and, for example, can be performed in one way, such as a fuel cell system, a vehicle equipped with the fuel cell system, a control method for the fuel cell system, a computer program to perform the functions of these systems, vehicle and method of control and a recording medium that records the computer program. Brief description of the drawings Characteristics, advantages and technical and industrial significance of the exemplary modalities of the invention will be described below with reference to the accompanying drawings, in which similar numerals represent similar elements and in which: Figure 1 is a schematic view showing the configuration of a fuel cell system according to a first embodiment of the invention, Figure 2 is a schematic view showing the electrical configuration of the fuel cell system according to the first embodiment of the invention, Figure 3A and Figure 3B are graphs to illustrate the production control over a fuel cell in the fuel cell system according to the first embodiment of the invention, Figure 4A, Figure 4B and Figure 4C are graphs to illustrate the deterioration of the fuel cell's performance due to the negative voltage generated because of the scarce supply of hydrogen in the fuel cell system, Figure 5 is a flow chart to illustrate the procedure for a negative voltage recovery process in the fuel cell system, Figure 6 is a graph to illustrate the regulation in which the transition from the negative voltage from the permissible level of power generation to the level of performance deterioration occurs in the fuel cell system, Figure 7 is a graph to illustrate a permissible operating range of the fuel cell, defined through an experiment, in the fuel cell system, Figure 8A, Figure 8B and Figure 8C are graphs to illustrate the current restriction process in the fuel cell system, Figure 9 is a schematic view showing the electrical configuration of a fuel cell system according to a first modality alternative to the first modality, 11/44 Figure 10 is a flowchart to illustrate the procedure for a negative voltage recovery process according to the first alternative to the first modality, Figure 11 is a schematic view showing the electrical configuration of a fuel cell system according to a second alternative to the first, Figure 12 is a flow chart showing the procedure for a negative voltage recovery process according to the second alternative to the first, Figure 13 is a flow chart showing the procedure for a negative voltage recovery process according to a second modality, Figure 14 is a graph to illustrate the current restriction process according to the second modality, Figure 15 is a schematic view showing the electrical configuration of a fuel cell system according to a third modality, Figure 16 is a flowchart showing the procedure for a negative voltage recovery process according to a third modality, Figure 17 is a graph showing a change in the permissible operating range resulting from a change in the humidity state within the fuel cell according to the third modality, Figure 18 is a flowchart showing the procedure for a permissible lane change process according to the third modality, Figure 19 is a graph showing an example of a moisture determination map used to determine the target humidity within the fuel cell according to the third modality, Figure 20A, Figure 20B and Figure 20C are graphs to illustrate a determination process for determining a target humidity within the fuel cell using a moisture determination map and a change process for changing a map of the allowable range according to the third modality, Figure 21A and Figure 21B are graphs to illustrate a process of changing the permissible range in a fuel cell system according to a fourth modality, Figure 22 is a flowchart showing the procedure for a negative voltage recovery process according to a fifth modality, Figure 23 is a flowchart showing the procedure for a refrigerant control process according to the fifth modality, Figure 24 is a flowchart showing the procedure for a negative voltage recovery process according to a sixth modality, Figure 25A and Figure 25B are flowcharts showing respectively the first and the second refrigerant control processes according to the sixth modality and Figure 26A and Figure 26B are graphs to illustrate a change in time in the cell temperature of a negative voltage cell under a low temperature environment according to the reference examples of the invention. Detailed description of the modalities Figure 1 is a schematic view showing the configuration of a fuel cell system according to a first embodiment of the invention. The fuel cell system 100 includes a fuel cell 10, a control unit 20, a cathode gas supply unit 30, a cathode gas exhaust unit 40, an anode gas supply unit 50, an anode gas exhaust unit 60 and a refrigerant supply unit 70. The fuel cell 10 is a polymer electrolyte fuel cell that is supplied with hydrogen (anode gas) and air (cathode gas) as reaction gases to generate the electrical force. The fuel cell 10 has a stack structure in which a plurality of power generation elements 11 called single cells are stacked. Each power generation element 11 includes a membrane electrode assembly (not shown) and two separators (not shown). The membrane electrode assembly is the force generating element in which the electrodes are arranged on both surfaces of an electrolyte membrane. The two separators compress the membrane electrode assembly. Here, the electrolyte membrane can be formed of a thin film of solid polymer that exhibits favorable conductivity of the proton in a wet state. In addition, each electrode can be formed of carbon (C). Note that an electrode surface, facing the electrolyte membrane, supports a catalyst (eg, platinum (Pt)) to facilitate the reaction of force generation. Distribution tubes (not shown) for reaction gases and refrigerant are provided for each power generation element 11. The reaction gases in the distribution tubes are supplied to the power generation portion of each power generation element 11 via of respective gas flow passages provided for each power generation element 11. The control unit 20 is formed by a microcomputer that includes a central processing unit and a main storage. The control unit 20 accepts a request to produce power from an external load 200. In response to the request, the control unit 20 controls structural units of the fuel cell system 100 described below to make the fuel cell 10 generate the force. electrical. 13/44 The cathode gas supply unit 30 includes a cathode gas line 31, an air compressor 32, an air flow meter 33, an on-off valve 34 and a humidification unit 35. The cathode gas line 31 is connected to the cathode of the fuel cell 10. The air compressor 32 is connected to the fuel cell 10 via the gas line of cathode 31. The air compressor 32 absorbs and compresses the external air and supplies the compressed air to the cell of fuel 10 as cathode gas. The air flow meter 33 measures the flow rate of the external air absorbed by the air compressor 32 in an upstream portion of the air compressor 32 and then transmits the measured flow rate to the control unit 20. The control unit 20 triggers the air compressor 32 based on the flow rate measured to control the amount of air supplied to the fuel cell 10. The on-off valve 34 is provided between the air compressor 32 and the fuel cell 10. The on-off valve 34 opens or closes in response to the flow of air supplied in the cathode gas line 31. Specifically, the on switch-off 34 is normally closed and opens when air having a predetermined pressure is supplied from the air compressor 32 to the cathode gas line 31. The humidification unit 35 humidifies the high pressure air pumped from the air compressor 32. In order to maintain a moist state of the electrolyte membranes to obtain favorable proton conductivity, the control unit 20 uses the humidification unit 35 to control the amount of humidification of the air supplied to the fuel cell 10 to thereby regulate the wet state within the fuel cell 10. The cathode 40 exhaust gas unit includes a cathode 41 exhaust gas line, a pressure regulating valve 43 and a pressure measurement unit 44. Cathode 41 exhaust gas line is connected to the cathode fuel cell 10 and exhaust the cathode exhaust gas to the outside of the fuel cell system 100. The pressure regulating valve 43 regulates the pressure of the cathode exhaust gas (fuel cell back pressure 10) in the line exhaust gas from cathode 41. Pressure measurement unit 44 is supplied in an upstream portion of pressure regulating valve 43. Pressure measurement unit 44 measures the pressure of the exhaust gas from the cathode and then transmits the pressure measured for the control unit 20. The control unit 20 regulates the degree of opening of the pressure regulating valve 43 based on the pressure measured by the pressure measuring unit 44. The anode gas supply unit 50 includes an anode gas line 51, a hydrogen tank 52, an on-off valve 53, a regulator 54, an injector 55 and two pressure measuring units 56u and 56d. The hydrogen tank 52 is connected to the anode of the fuel cell 10 through the gas line of anode 51, and supplies the filled hydrogen in the tank to the fuel cell 10. Note that the cell system 14/44 la of fuel 100 may include a reform unit instead of the hydrogen tank 52 as a source of hydrogen supply. The refurbishment unit reforms hydrocarbon-based fuel to produce hydrogen. The on-off valve 53, regulator 54, the first pressure measurement unit 56u, the injector 55 and the second pressure measurement unit 56d are supplied in the anode gas line 51 from the upstream side (adjacent side to the hydrogen tank 52) in the declared order. The on-off valve 53 opens or closes in response to a command from the control unit 20. The on-off valve 53 controls the flow of hydrogen from the hydrogen tank 52 to the upstream side of the injector 55. Regulator 54 is a pressure reduction valve to regulate the hydrogen pressure in an upstream portion of the injector 55. The degree of opening of the regulator 54 is controlled by the control unit 20. The injector 55 is an electromagnetically driven on-off valve from which the valve element is electromagnetically driven according to a trigger interval or opening duration of the valve established by the control unit 20. The control unit 20 controls the trigger interval or the duration of opening of the injector valve 55 to control the amount of hydrogen supplied to the fuel cell 10. The first and second pressure measuring units 56u and 56d respectively measure the hydrogen pressure in an upstream portion of the injector. 55 and the hydrogen pressure in a downstream portion of the injector 55 and then transmit the measured pressures to the control unit 20. The control unit 20 uses these measured pressures to determine the actuation interval or opening duration of the valve. injector 55. The anode gas circulation exhaust unit 60 includes an anode exhaust gas line 61, a gas-liquid separation unit 62, anode gas circulation line 63, a hydrogen circulation pump 64, an anode drain line 65 and a drain valve 66. the anode exhaust gas line 61 connects the anode outlet of the fuel cell 10 into the liquid gas separation unit 62. the anode exhaust gas line 61 it takes the exhaust gas from the anode which includes unreacted gas (hydrogen, nitrogen and so on) that is not used in the force generation reaction for the gas-liquid separation unit 62. The gas-liquid separation unit 62 is connected to the anode 63 gas circulation line and anode 65 drain line. The liquid-gas separation unit 62 separates components from the gas and the water content included in the exhaust gas anode exhaustion. The gas-liquid separation unit 62 takes the gas components to the anode 63 gas circulation line and carries the water content to the anode 65 drain line. The anode 63 gas circulation line is connected to the anode 51 gas line 15/44 in a downstream portion of the injector 55. The hydrogen circulation pump 64 is supplied in the gas circulation line of anode 63. The hydrogen included in the gas components separated by the gas-liquid separation unit 62 is pumped to the anode gas line 51 by the hydrogen circulation pump 64. Thus, in the fuel cell system 100, the hydrogen included in the anode exhaust gas is circulated and refilled to fuel cell 10 to improve this efficiency of hydrogen use. The anode drain line 65 is used to drain the water content separated by the gas-liquid separation unit 62 to the outside of the fuel cell system 100. The drain valve 66 is provided on the anode drain line 65 Drain valve 66 opens or closes in response to a command from control unit 20. Control unit 20 normally closes drain valve 66 during operation of fuel cell system 100 and opens drain valve 66 in a predetermined drain regulation set in advance or a regulation in which the inert gas included in the anode exhaust gas is exhausted. The refrigerant supply unit 70 includes a refrigerant line 71, a radiator 72, a refrigerant circulation pump 73 and two refrigerant temperature measurement units 74 and 75. Refrigerant line 71 connects an inlet manifold of refrigerant in a refrigerant outlet manifold. The coolant inlet manifold and coolant outlet manifold are provided for fuel cell 10. Coolant line 71 circulates the coolant to cool fuel cell 10. Radiator 72 is provided in the coolant line. refrigerant 71. The radiator 72 exchanges heat between the refrigerant flowing in the refrigerant line 71 and the outside air to thereby cool the refrigerant. The refrigerant circulation pump 73 is provided in the refrigerant line 71 in a portion downstream of the radiator 72 (adjacent to the refrigerant inlet of the fuel cell 10). Refrigerant circulation pump 73 pumps cooled refrigerant through radiator 72 to fuel cell 10. The two refrigerant temperature measuring units 74 and 75 are supplied respectively near the refrigerant outlet of the fuel cell 10 and close to the inlet. of the refrigerant in the fuel cell 10 in the refrigerant line 71. The two refrigerant temperature measuring units 74 and 75 transmit the measured temperatures to the control unit 20. The control unit 20 detects the operating temperature of the cooling cell respectively. fuel 10 from a difference between the respective temperatures measured by the two refrigerant temperature measuring units 74 and 75 and then controls the amount of refrigerant pumped by the refrigerant circulation pump 73 based on the operating temperature detected to regulate in this way the operating temperature of the com16 / 44 bustív cell el 10. Figure 2 is a schematic view showing the electrical configuration of the fuel cell system 100. The fuel cell system 100 includes a secondary battery 81, a DC / DC converter 82 and a DC / AC inverter 83. In addition, the fuel cell system 100 includes a cell voltage measurement unit 91, a current measurement unit 92, an impedance measurement unit 93 and a charge status detection unit 94. The fuel cell 10 is connected to the DC / AC inverter 83 via a DCL power supply line. Secondary battery 81 is connected to the DCL power supply line via the DC / DC converter 82. The DC / AC inverter 83 is connected to external load 200. Note that in fuel cell system 100, part of the production the electrical force of the fuel cell 10 and the secondary battery 81 is used to drive the auxiliaries that make up the fuel cell system 100; however, wiring for auxiliaries is not shown and its description is omitted. The secondary battery 81 acts as an auxiliary power supply to the fuel cell 10. The secondary battery 81 can be formed, for example, from a chargeable and dischargeable lithium ion battery. The DC / DC converter 82 functions as a charge / discharge control unit that controls the charge / discharge of the secondary battery 81. The DC / DC converter 82 variablely regulates the voltage level of the DC power supply line DCL in response to a command from the control unit 20. If the electrical power output from the fuel cell 10 is insufficient for an external load 200 production request, the control unit 20 instructs the DC / DC converter 82 to discharge the secondary battery 81 in order to compensate for insufficient electrical power. The DC / AC inverter 83 converts the electrical power from the direct current obtained from fuel cell 10 and secondary battery 81 to electrical power from alternating current, and then supplies the electrical power from alternating current to external load 200. Note that when the regenerative electrical force is generated at external load 200, the regenerative electrical force is converted to direct current electrical force by the DC / AC inverter 83, and then the secondary battery 81 is charged with direct current electrical force by the DC / DC converter 82 . The cell voltage measurement unit 91 is connected to each power generation element 11 of the fuel cell 10 to measure the voltage (cell voltage) of each power generation element 11. The cell voltage measurement unit 11 91 transmits the measured voltages from the cell to the control unit 20. Note that the cell voltage measurement unit 91 can transmit only the lowest voltage in the 17/44 cell between the measured cell voltages to the control unit 20. The current measuring unit 92 is connected to the DCL power supply line DCL. The current measurement unit 92 measures the current output of the fuel cell 10, and then transmits the measured current to the control unit 20. The charge status detection unit 94 is connected to the secondary battery 81. The charge status detection 94 detects the charge status (SOC) of the secondary battery 81, and then transmits the detected SOC to the control unit 20. The impedance measurement unit 93 is connected to the fuel cell 10. The impedance measurement unit 93 applies alternating current to the fuel cell 10 to thereby measure the impedance of the fuel cell 10. Here, it is known that the impedance of the fuel cell 10 varies with the amount of water content present within fuel cell 10. That is, the correlation between the impedance of fuel cell 10 and the amount of water content (moisture) within fuel cell 10 is acquired in advance and then the impedance of the fuel cell 10 is measured to make it possible to obtain in this way the amount of water (moisture) content within the fuel cell 10. Incidentally, in the fuel cell system 100 according to the first modality, the control unit 20 also functions as a unit of measurement of the accumulated value of the chain 21. The unit of measurement of the accumulated value of the chain 21 integrates the production of the chain of the fuel cell 10, measured by the current measurement unit 92, with respect to time for a predetermined period of time to calculate in this way the accumulated current value that indicates the production of the electric charge of the fuel cell 10. The Control 20 uses the accumulated current value to perform the current restriction process to suppress the deterioration of the power generation performance of the power generation elements 11, and its detailed description will be described later. Figure 3A and figure 3B are graphs to illustrate the production control over fuel cell 10 of fuel cell system 100. Figure 3A is a graph showing the characteristics W1 of fuel cell 10, in which the axis The ordinate geometry represents the electric force of the fuel cell 10 and the geometric axis of the abscissa represents the current of the fuel cell 10. In general, the characteristics W1 of a fuel cell are shown by a rising convex curve. Figure 3B is a graph showing the characteristics V-l of the fuel cell 10, in which the geometric axis of the ordinates represents the voltage of the fuel cell 10 and the geometric axis of the abscissa represents the current of the fuel cell 10. From 18/44 In general, the V-l characteristics of a fuel cell are shown by a horizontal sigmoid curve that declines with an increase in current. Note that in figure 3A and figure 3B, the geometric axes of the abscissa of the respective graphs correspond to each other. The control unit 20 pre-stores these characteristics W1 and characteristics Vl of the fuel cell 10. The control unit 20 uses the characteristics W1 to acquire a target current that must be produced from the fuel cell 10 for a Pt electrical force required from the external load 200. In addition, the control unit 20 uses the characteristics Vl to determine a target voltage Vt of the fuel cell 10 to produce the target current It obtained from the characteristics Wl. The control unit 20 adjusts the target voltage Vt in the DC / DC converter 82 to make the DC / DC converter 82 regulate the voltage of the DCL power supply line. Incidentally, as described above, in the fuel cell 10, the reaction gases flow from the distribution pipes into the gas flow passages of each power generating element 11. However, the gas flow passages from each power element. Power generation 11 can be blocked possibly by water content, or the like, produced in fuel cell 10. If fuel cell 10 is induced to continue power generation in the state where the gas passages from part of the generating elements power generators 11 are blocked, the power generation reaction is suppressed because of insufficient supply of reaction gases on the part of the power generation elements 11. On the other hand, the other power generation elements 11 continue the power generation , then the part of the power generation elements 11 acts as resistance in the fuel cell 10 to generate the negative voltage in this way . Next, in the specification, the power generation element 11 in which the negative voltage is generated is called a “negative voltage cell 1Γ. It is known that, as the negative voltage state of each negative voltage cell 11 continues, the degradation of the electrodes of each negative voltage cell 11 progresses and then the power generation performance of the fuel cell 10 deteriorates. Here, the negative voltage occurs because of the scarce supply of hydrogen that is caused by inhibiting the supply of hydrogen to the anode or because of the scarce supply of oxygen that is caused by inhibiting the supply of oxygen to the cathode. In the case of the occurrence of negative voltage due to the scarce supply of hydrogen to the anode, the performance of the fuel cell 10 deteriorates as follows depending on the level of the negative voltage. Figure 4A through figure 4G are graphs to illustrate the deterioration in the performance of the fuel cell 10 due to the negative voltage generated through the scant supply of hydrogen in any of the power generation elements 11. Figure 4A is 19/44 a graph showing a variation in the cell voltage when the negative voltage is generated in any of the power generation elements 11. In the graph in figure 4A, the geometric axis of the ordinates represents the cell voltage and the geometric axis of the abscissas represents time. In the graph, the negative voltage occurs at time to and the cell voltage declines substantially vertically to voltage Vi. After that, the cell voltage is kept constant around the V 1 voltage ( declines substantially vertically to the V 2 voltage again at time h and is then kept substantially constant at the V 2 voltage. In this way, the level of the negative voltage that is generated through scarce hydrogen supply decreases in two stages in a substantially gradual manner over a period of time. Here, at the anode of each negative voltage cell 11, protons are produced by the next chemical reaction in order to compensate for the scarce supply of hydrogen. That is, protons are produced by the water-splitting reaction expressed by the following reaction formula (1) over a period of time to time ti, and protons are produced by the carbon oxidation reaction that constitutes the electrode (anode), expressed by the following reaction formula (2), after time t 2 . 2H 2 O-> O 2 + 4H + + e (1) C + 2H 2 O -> CO 2 + 4H + + 4e (2) Figure 4B shows a graph showing the power generation performance of each negative voltage cell 11 over a period of time to time h. Figure 4C shows a graph showing the power generation performance of each negative voltage cell 11 after time h. Each of figures 4B and figure 4C includes a graph G t . v showing the lV characteristics of each negative voltage cell 11, in which the geometric axis of the abscissa represents the current density and the geometric axis of the ordinates represents the voltage of the cell and a graph G | R showing the lR characteristics of each negative voltage cell 11, in which the geometric axis of the abscissa represents the current density and the geometric axis of the ordinates represents the resistance. Note that in order to show the changes in characteristics, in figure 4C, the graphs G ( . V and G |. R shown in figure 4B are indicated by the dashed lines, and the arrows that indicate the directions in which the respective graphs change are shown. Thus, if the water division reaction is taking place at the anode of each negative voltage cell 11 as in the case over a period of time from time to time ti, the deterioration of the power generation performance of fuel cell 10 is relatively suppressed (figure 4B). Note that in the case of figure 4B, the l-V characteristics of each power generation element 11, in which no negative voltage is generated, substantially coincide with the l-V characteristics of each negative voltage cell 11. For 20/44 on the other hand, if the carbon oxidation reaction is taking place at the anode of each negative voltage cell 11 as in the case after time ti, the lV characteristics of each negative voltage cell 11 decrease, and the internal resistance of each negative voltage cell 11 increases (figure 4C). Note that the power generation performance of the fuel cell 10 deteriorates because of the deterioration of the performance of each negative voltage cell 11. Furthermore, if the carbon of the electrode is oxidized as in the case after time t 1 (it is difficult to recover the power generation performance of each negative voltage cell 11 even after the restart of the fuel cell 10. Next, in the specification, the level of negative voltage at which power generation can continue while suppressing the deterioration of the power generation performance of the fuel cell 10 through the water division reaction at the anode of each negative voltage cell. 11, as in the case during a period from time to time t 1 (it is called the “permissible level of force generation”. In addition, the level of the negative voltage, at which the electrode degradation of each negative voltage cell 11 occurs and the power generation performance of the fuel cell 10 deteriorates as in the case after time ti, it is called a "performance deterioration level". In the fuel cell system 100 according to the first embodiment, when the negative voltage has been detected in any of the power generation elements 11 of the fuel cell 10, the negative voltage state is recovered through the voltage recovery process negative described below. Note that, in the negative stress recovery process, when it is determined that the negative stress is due to the scant supply of hydrogen, production control that prevents the negative stress level from reaching the level of performance deterioration is performed to recover from this negative voltage form while avoiding negative voltage cell electrode degradation 11. Figure 5 is a flowchart to illustrate the procedure of the negative voltage recovery process performed by the control unit 20. After the normal operation of the fuel cell 10 (step S5) is initiated, when the negative voltage has been detected in at least one of the power generation elements 11 by the voltage measurement unit of cell 91, the control unit 20 begins the process at step S20 and in the following steps (step S10). In step S20, the control unit 20 causes the accumulated current value measurement unit 21 to start measuring the accumulated current value used in a current restriction process (described later). Here, at the stage where the negative voltage was detected in step S10, it is not determined whether the reason why the negative voltage is generated is due to the scarce supply of hydrogen to the anode or due to the scarce supply of oxygen to the cathode. Then, in step S30, the control unit 20 initially increases the rotational speed 21/44 of the air compressor 32 to increase the amount of air supplied to the fuel cell 10. If negative voltage is generated because of the scarce supply of oxygen to the cathode, this operation eliminates the insufficient supply of air and also cleans the water content that blocks the flow of gas on the cathode side to make it possible to remove the block. If the voltage of the negative voltage cell 11 increases after the amount of air supplied is increased, the control unit 20 determines that the negative voltage cell 11 has recovered from the negative voltage and then returns to the control of normal operation on the cell of fuel 10 (step S40). On the other hand, if the negative voltage cell 11 has not recovered from the negative voltage even with an increase in the amount of air supplied, the control unit 20 determines that the reason the negative voltage is generated is due to the scant supply of hydrogen , and then the current restriction process begins to avoid electrode degradation and deterioration of power generation performance in step S50 and in the following steps. In step S50, the control unit 20 acquires the accumulated current value of the measurement unit from the accumulated current value 21 based on the current production of the fuel cell 10 in a period during which the negative voltage is generated. In steps S60 and S70, the control unit 20 uses the accumulated current value acquired in step S50 to obtain a limit of electric power production from fuel cell 10, and then induces fuel cell 10 to produce electric power within of the limited range. By doing so, the degradation of the electrode of each negative voltage cell 11 and the deterioration of the power generation performance of the fuel cell 10 are suppressed. Here, before the detailed detailed operations in steps S60 and S70 are described, the correlation between the accumulated current value and the limit of the production of the electric force of the fuel cell 10 will be described to prevent the electrode oxidation and the deterioration of the performance of the generation of force due to the negative voltage, which was obtained through an experiment by the inventors of the invention. Figure 6 is a graph showing the results of the experiment conducted by the inventors of the invention in order to investigate the regulation in which the transition from the negative voltage from the permissible level of power generation to the level of performance deterioration takes place. In the experiment, for a selected one of the power generation elements 11, in the state where the gas flow passage on the anode side is blocked, the force generation that causes the fuel cell 10 to produce a constant current at constant flow rates of the reaction gases at a constant operating temperature was performed intermittently five times in a constant time interval. The graph in figure 6 shows a variation in the negative tension over time for each occasion of power generation. 22/44 During the first to the third generation of force, the measurement time ended before the negative voltage reached the permissible level of force generation. However, during the fourth generation of force, the cell voltage decreased to the level of performance deterioration in the measurement progress. Then, during the fifth generation of power, the cell's voltage decreased to the level of performance deterioration immediately after the power generation started. The inventors of the invention repeated a similar experiment with a different current production from the fuel cell 10 and found that the cumulative time that the transition from the negative voltage from the permissible level of power generation to the level of performance deterioration happens is substantially constant for each current density even when a stop and restart of power generation are repeated after the negative voltage is generated. This is presumably because an oxidation film formed at the anode of the negative voltage cell 11 through the water division reaction is strong enough to remain uniform when the power generation is interrupted. Therefore, it is presumed that the electrical charge that can be produced during a period when the negative voltage occurs until when the negative voltage reaches the level of performance deterioration is substantially constant for each current density and the electrical charge production during that time. remains as the story of power generation during that time. Through these findings, the inventors of the invention found that the operating condition that is permissible for the fuel cell 10 before the transition from the negative voltage to the level of performance deterioration can be defined by the current density of the fuel cell 10 in a period during which the negative voltage of the permissible level of power generation is generated and the accumulated current value of the fuel cell 10 during that time. Figure 7 is a graph showing the result of the experiment conducted by the inventors of the invention in order to define the permissible operating condition for the fuel cell 10 in a period during which the negative voltage of the permissible level of power generation is generated . In this experiment, the gas flow path on the anode side of any of the power generation elements 11 was blocked, and then the accumulated current value was measured when fuel cell 10 is induced to continue the power generation of when the negative voltage occurs even when the negative voltage reaches the level of performance deterioration. Then, the accumulated current value was measured with a different current density of the fuel cell 10 multiple times to obtain the accumulated current value for each current density. Note that in this experiment, the flow rates of the reaction gases supplied to the fuel cell 10 and the operating temperature of the fuel cell 10 were constant. Figure 7 is a graph that is obtained in such a way that the geometric axis of the 23/44 denadas represents an accumulated current value, the geometric axis of the abscissa represents a current density and the measured results of the above experiment are marked. In this way, the correlation between the current densities of the fuel cell 10 in a period during which the negative voltage of the permissible level of power generation is generated and the accumulated current values permissible for the fuel cell 10 during that time is shown by a downward convex decline curve. That is, as the current density of the fuel cell 10 in the period during which the negative voltage of the permissible level of power generation is generated (hereinafter, also called as the "permissible period of power generation") increases, the cumulative value of the permissible current for the fuel cell 10 during that time reduces. The accumulated current value decreases substantially exponentially as the current density increases. Here, in Figure 7, the strip hatched below the downward convex curve can be understood as a strip that includes a combination of the current density and the accumulated current value that are permissible for the fuel cell 10 during the permissible generation period. force. In the following, this range is called a “permissible operating range”. That is, in the case where the negative voltage is generated because of the scant supply of hydrogen, when the fuel cell 10 is induced to produce a combination of the current density and the accumulated current value that fall within the operating range, it is possible that the fuel cell 10 continues to generate power while preventing the negative voltage from reaching the level of performance deterioration. Note that, as can be understood from the fact that the geometric axis of the ordinates of the graph is an accumulated current value, the permissible operating range reduces with an increase in the duration of the power generation of the fuel cell 10 after the voltage negative occurs. In the fuel cell system 100 according to the first embodiment, the control unit 20 pre-stores the correlation between the cumulative current permissible values for the fuel cell 10 and the permissible current densities for the fuel cell 10 in a period during which the negative voltage is generated, shown by the graph in figure 7, as a map. Then, the map (hereinafter referred to as the “permissible range map”) is used to perform the current restriction process in steps S60 and S70 (figure 5). Figure 8A through figure 8C are schematic graphs to illustrate processes in steps S60 and S70. In figure 8A through figure 8C, the map of the permissible range above M PA is shown by the graph of which the geometric axis of the ordinates represents an accumulated current value and the geometric axis of the abscissa represents a current density. In the graphs of the permissible range maps M PA in figure 8A and figure 8B, the permissible range 24/44 operating speed is hatched. Here, in the fuel cell system 100 according to the first embodiment, a lower limit current density in m (also called “minimum current density in m ”) that must be produced from the fuel cell 10 is adjusted in order to that the control unit 20 continues operation of the fuel cell system 100. Therefore, the range at or below the minimum current density in m is not included in the permissible operating range. In step S60, the control unit 20 acquires a current density h for an accumulated current value Qei acquired by the measurement unit of the accumulated current value 21 (figure 8A). In the following, the current density acquired using the allowable range map M PA is also called a "limit current density". Note that the accumulated value of the current Qei at that time is obtained based on the current production of the fuel cell 10 during the processes of steps S20 to S60. In step S70, the control unit 20 sets the current limit density h obtained in step S60 as a current density that is currently permissible for fuel cell 10, and then causes fuel cell 10 to generate electrical force at a density current i 1c (also called “restricted current density i 1c ”) which is less than the limit current density ii. Specifically, the control unit 20 can subtract a preset value Ai from the limit current density h to calculate the restricted current density h c (hc = h - Ai). Note that the preset value Ai may vary depending on the density of the limit current. Specifically, it is also applicable that, as the limit current density decreases, the Ai value is increased. The permissible operating range in the permissible range map M PA is reduced by the accumulated value of the current Qei in the direction of the geometric axis of the ordinates, then, in step S70, when the power generation is started at the restricted current density ii c which is less than the limit current density ii, the production of electrical power from the fuel cell 10 falls within the permissible operating range. Thus, it is possible to continue the operation of the fuel cell 10 while preventing degradation of the electrode. Here, the control unit 20 begins the process to recover the scarce supply of hydrogen in step S80 while the current is restricted in order to be able to continue the operation of the fuel cell 10. Specifically, it is also applicable that the flow rate of the hydrogen supplied to the fuel cell 10 is increased by regulating the actuation interval or opening duration of the injector valve 55, increasing the rotational speed of the hydrogen circulation pump 64, or similar, to increase the pressure of the hydrogen in the cell of fuel 10. Note that when the fuel cell system 100 is placed under a low temperature environment, the flow of gas flow from the anode may be blocked by the frozen water content. So in that case, the process for increasing The temperature of the fuel cell 10 can be performed, for example, the rotational speed of the refrigerant circulation pump 73 is decreased. After the process of recovering the shortage of hydrogen supply in step S80 starts, when the negative voltage cell 11 has not yet recovered from the negative voltage, the control unit 20 repeats the current restriction process in steps S50 to S70 again (step S90). In step S50, as in the previous case, the control unit 20 acquires an accumulated value of current Qe 2 based on the current production of the fuel cell 10 from when the negative voltage was detected up to the current time (step S50). Then, the map of the permissible range M PA is used to acquire a limit current density i 2 corresponding to the accumulated current value Qe 2 (figure 8B). In step S70, the control unit 20 causes the fuel cell 10 to generate electrical power at a restricted current density i 2c which is less than the limit current density i 2 . Figure 8C is a schematic graph to illustrate a variation in the density of the limit current in the current restriction process. The current restriction process in steps S50 to S80 is repeatedly performed until the negative voltage cell 11 recovers from the negative voltage (step S90). During the repetition of the current restriction process, the limit current density decreases gradually over the curve shown in the graph (arrows in the graph) with an increase in the accumulated current value. In addition, the current production of the fuel cell 10 gradually decreases along the curve shown in the graph as in the case of the variation in the density of the limit current. Note that when the restricted current density acquired in step S60 is less than or equal to the minimum current density in m , the control unit 20 determines that the negative voltage cell 11 has not recovered from the negative voltage and the electrical force Minimum fuel cell 10 cannot be obtained, and then perform the restart process for fuel cell 10. In this way, with the fuel cell system 100 according to the first modality, when it is determined in the process of recovering the negative voltage that the reason why the negative voltage is generated is due to the scant supply of hydrogen, the generation of force continues while suppressing a decrease in the negative voltage to the level of performance deterioration through the current restriction process. Then, during the current restriction process, the process for recovering the negative voltage is performed. Thus, it is possible to suppress the deterioration of the power generation performance of the fuel cell 10 and the degradation of the electrodes of the fuel cell 10 due to the negative voltage. In the following, a first alternative to the first will be described. Figure 9 is a schematic view showing the electrical configuration of a fuel cell system 100a according to the first alternative embodiment to the first modality of the invention. Figure 9 is substantially the same as Figure 2, except that a unit for recording the accumulated current value 23 is added. Note that the other configuration of the fuel cell system 100a in this example configuration is similar to that of the fuel cell system 100 according to the first modality (figure 1). The unit for recording the accumulated current value 23 (figure 9) of the fuel cell system 100a is formed of a non-volatile erasable and rewritable data memory, such as an erasable programmable reading memory (EPROM). Figure 10 is a flowchart showing the procedure for a negative voltage recovery process performed by the fuel cell system 100a. Figure 10 is substantially the same as Figure 5, except that step S100 is added after step S90. In the fuel cell system 100a, when the negative voltage has been detected in the fuel cell 10, the negative voltage recovery process is performed as in the case of the fuel cell system 100 according to the first embodiment. Then, in the negative voltage recovery process, when it is determined that the reason why the negative voltage is generated is due to the scant supply of hydrogen, the current restriction process similar to that described in the first modality is performed (steps S50 to S90). When the negative voltage cell 11 recovers from the negative voltage during the current restriction process, the control unit 20 records the accumulated current value used in the current restriction process in the recording unit of the accumulated current value 23 (step S100). Here, it is assumed that the negative voltage cell 11 has recovered from the negative voltage through the current restriction process. In such a case as well, unless maintenance of the power generating element 11, in which the negative voltage was generated, is conducted, the negative voltage is generated in that power generating element 11 again and then a permissible operating range when the current restriction process is initiated will be the permissible operating range at the time the previous current restriction process ends. Then, in step S100, the control unit 20 records non-volatile the accumulated current value in preparation for the next current restriction process. Here, the control unit 20 identifies the power generation elements 11 in which negative voltage is generated (negative voltage cells 11) at the time when negative voltage occurs and writes an accumulated current value to the accumulation value recording unit. current 23 for the corresponding negative voltage cells 11. When the current restriction process is executed again, the control unit 20 loads the accumulated current value that corresponds with each negative voltage cell 11 and which is recorded in the recording unit of the accumulated current value 23 as an initial value of the accumulated current value and then starts measuring the value 27/44 accumulated current in step S20. That is, the control unit 20 performs the current restriction process using a total accumulated current value that is obtained by adding the accumulated current value recorded in the recording unit to the accumulated current value 23 and an accumulated current value from production flow of the fuel cell 10 after the current restriction process is resumed. Note that when the power generating element 11 that causes the generation of the negative voltage is maintained, the accumulated current value of the maintained power generating element 11, recorded in the recording unit of the accumulated current value 23, can be initialized. In the following, a second alternative to the first will be described. Figure 11 is a schematic view showing the configuration of a fuel cell system 100b according to the second alternative embodiment to the first embodiment of the invention. Figure 11 is substantially the same as Figure 9, except that a warning unit 25 is added. Note that the other configuration of the fuel cell system 100b in this example configuration is similar to that of the fuel cell system 100a in the first alternative mode (figure 9). The warning unit 25 (figure 11) of the fuel cell system 100b visually or aurally warns a user of the fuel cell system 100b about maintenance of the fuel cell 10 in response to a command from the control unit 20 The warning unit 25 can be formed, for example, from a monitor or light emitting unit that is recognizable by the user or can be formed from a loudspeaker or a bell. Figure 12 is a flow chart showing the procedure for a negative voltage recovery process performed by the fuel cell system 100b. Figure 12 is substantially the same as Figure 10, except that steps S62 and S63 are added. In the negative voltage recovery process performed by the fuel cell system 100b according to this configuration example, the map of the allowable range Mpa (figure 8A to figure 8C) is used to obtain a limit current density in step S60 and then it is determined in step S62 whether the density of the limit current is lower than or equal to the predetermined threshold. Here, the predetermined threshold can be, for example, a current density required to obtain the electrical force by which the operation of the fuel cell system 100b can continue. When it is determined in step S62 that the limit current density is less than the predetermined threshold, the control unit 20 determines that it is difficult to continue operation of the fuel cell system 100b unless the maintenance of the fuel cell 10 is conducted, and then causes the warning unit 25 to perform the warning process (step S63). Specifically, in the warning process, it is applicable that the operation of the fuel cell system 100b is stopped and then the user is informed28 / 44 about a message that induces the replacement of the negative voltage cell 11. Thus, with the fuel cell system 100b according to this configuration example, the information that the electrical power production of the fuel cell 10 is restricted and it is difficult to continue the operation of the fuel cell system 100b in the process of current restriction is provided to the system user by warning unit 25. Thus, the user is able to become aware of a situation in which maintenance of fuel cell 10 must be conducted. Note that it is applicable that when the accumulated current value is greater than or equal to the predetermined threshold while the current restriction process is performed or when the accumulated current value is recorded in step S100, the control unit 20 informs the user of this fact via warning unit 25. In the following, a second modality will be described. Figure 13 is a flowchart showing the procedure for a negative voltage recovery process according to the second embodiment of the invention. Figure 13 is substantially the same as Figure 5, except that steps S61 and S71 are provided instead of steps S60 and S70 and step S91 is added. Note that the configuration of a fuel cell system according to the second modality is similar to that of the fuel cell system 100 described in the first modality (figure 1 and figure 2). In the fuel cell system according to the second modality, in steps S50 to S91, an accumulated current permissible value for the fuel cell 10 is obtained and then the current restriction process is performed based on the accumulated current value . Figure 14 is a graph to illustrate the current restriction process according to the second modality and is a graph showing a map of allowable range M PA similar to that described in the first modality. In step S61, the control unit 20 acquires a limit current density ii corresponding to the accumulated value of current Qei acquired in step S50. Then, a restricted current density ii c that is less by a preset value than the limit current density h is determined as a production command value for fuel cell 10, and then fuel cell 10 is induced to generate electrical force at restricted current density ii c . In step S71, the control unit 20 uses the permissible range map M PA again to acquire an accumulated current value Qe 2 corresponding to the restricted current density i 1c which is a command value for fuel cell 10. A control unit 20 sets a lower value by a predetermined value than the accumulated current value Qe 2 as the accumulated current value (hereinafter also referred to as the “accumulated current limit value”) allowable for the fuel cell 10. Then, the control unit 20 performs the process to recover the scarce hydrogen supply in step S80 and then determines in step S90 whether the voltage cell Negative 29/44 11 recovered from the negative tension. When the negative voltage cell 11 recovers from the negative voltage, the control unit 20 resumes normal operation control (step S5). In addition, when the negative voltage cell 11 does not recover from the negative voltage, the control unit 20 acquires the accumulated current value in the period during which the negative voltage is generated from a unit of measurement of the accumulated current value 21, and then determines whether the accumulated current value has reached the accumulated current limit value acquired in step S71 (step S91). When the accumulated current value has not reached the accumulated current limit value, the control unit 20 repeats the steps in steps S80 and S90. When the accumulated current value reaches the accumulated current limit value in step S91, the control unit 20 resumes to step S61 and then adjusts a current density i 2c which is less by a preset value than the restricted current density h c , which has been set as a control value, as a new control value for fuel cell 10. In step S71, the permissible range map M PA is used to acquire an accumulated current value Qe 2 corresponding to the current density i 2c and then an accumulated current limit value is determined based on the accumulated current value Qe 2 . Thus, in the current restriction process according to the second modality, the control unit 20 uses the map of the permissible range M PA to obtain an accumulated current limit value corresponding to a current density established as a command value for the fuel cell 10. Then, until the accumulated current value is close to the accumulated current limit value, the fuel cell 10 is induced to continue the generation of force at the established current density as a command value. When the accumulated current value is close to the accumulated current limit value, the control unit 20 decreases the current density which is a command value and acquires an accumulated current limit value corresponding to the decreased command value again to make this way that the fuel cell 10 continues to generate power. By doing this, as indicated by the arrow in the graph in figure 14, the current density of the fuel cell 10 decreases along the curve shown in the graph in a gradual manner with an increase in the accumulated current value. With the fuel cell system according to the second modality as well, as in the case of the fuel cell system 100 according to the first modality, it is possible to suppress the deterioration of the power generation performance of the fuel cell 10 and the degradation of fuel cell electrodes 10 due to negative voltage. Note that it is also applicable for the control unit 20 to calculate an available power generation duration at a current density that is a value of 30/44 command based on an accumulated current limit value acquired from the permissible range map M PA and then control the regulation in which the current density, ie the command value, is decreased based on the duration of the generation of force. In the following, a third modality will be described. Figure 15 is a schematic view showing the electrical configuration of a 100B fuel cell system according to the third embodiment of the invention. Figure 15 is substantially the same as Figure 2, except that an on-off switch 84 is added to the DCL power supply line and a permissible range change unit 22 added to the control unit 20. Note that the other configuration of the 100B fuel cell system is similar to the configuration described in the first modality (figure 1). However, in the fuel cell system 100B according to the third embodiment, the fuel cell 10 is operated at a constant operating temperature. The on-off switch 84 is provided between the DC / DC converter 82 and the fuel cell 10. The on-off switch 84 opens or closes in response to a command from the control unit 20. When the on-off switch 84 is closed, the fuel cell 10 is electrically connected to the external load 200; whereas, when the power switch 84 is opened, fuel cell 10 is electrically isolated from external charge 200. Note that when fuel cell 10 is isolated from external charge 200, secondary battery 81 is capable of producing power electric supply for external load 200. In the fuel cell system 100B according to the third embodiment, the control unit 20 also functions as the permissible range change unit 22. The permissible range change unit 22 performs the process for changing the permissible operating range of the fuel cell 10 in a current restriction process of a negative voltage recovery process. Specific details of the process will be described later. Figure 16 is a flowchart showing the procedure for the negative voltage recovery process according to the third modality. Figure 16 is substantially the same as Figure 5, except that step S65 is added. In the fuel cell system 100B according to the third embodiment, as in the case of the fuel cell system 100 according to the first embodiment, the negative voltage recovery process is carried out. Then, in the process of recovering the negative voltage, when it is determined that the negative voltage is generated because of the scarce hydrogen supply, the current restriction process and the recovery process of the scarce hydrogen supply are performed. Here, in the current restriction process, when the permissible current for the fuel cell 10 is considerably less than a target current for the fuel cell 10 to supply the required electrical power of the external load 200, there is a pos 31/44 sibility that insufficient current may not be uniformly compensated by the secondary battery 81. Then, in the fuel cell system 100B according to the third modality, when the difference between the limit density of the current acquired in step S60 and the density of the current to produce the target current of the fuel cell 10 is greater than a predetermined value, the permissible range change unit 22 is induced to perform the permissible range change process (step S65). Figure 17 is a graph that illustrates a change in the permissible operating range due to a change in humidity within the fuel cell 10. The graph shown in figure 17 was obtained by conducting an experiment similar to the experiment conducted in order to obtain the graph of figure 7 in the state where the humidity inside the fuel cell 10 has been reduced. Note that in figure 17, as in the case of the graph in figure 7, the permissible operating range below the curve shown in the graph is hatched. In addition, in the graph in figure 17, for convenience, the dashed line that indicates the curve shown in the graph in figure 7 and the arrow that indicates a change in the curve of the dashed line are shown. The inventors of the invention found that, by decreasing the humidity inside the fuel cell 10, the curve showing the correlation between the accumulated current value and the current density in a permissible period of power generation changes upwards, and the range of allowable operation expands. The reason why the permissible operating range is expanded is because of the following reason. It is known that, in the permissible force generation period, the reaction expressed by the reaction formula (1) described above and the reaction expressed by the following reaction formula (3) progress at the anode of the negative voltage cell 11 to deactivate in this way the catalyst. Pt + 2H 2 O PtO 2 + 4H + + 4e (3) As the humidity inside the fuel cell 10 decreases, the amount of water content in the anode (the water content of the membrane electrode assembly) decreases, so the above reactions proceed gently and the deactivation of the catalyst is suppressed. Therefore, the permissible operating range expands by the amount that progress in deactivating the catalyst can be delayed. That is, by decreasing the humidity inside the fuel cell 10, the permissible operating range of the fuel cell 10 in the current restriction process can be expanded, so it is possible to increase the permissible current density for the fuel cell 10. Then , in the fuel cell system 100B according to the third embodiment, in the process of changing the permissible range described below, the humidity inside the fuel cell 10 is decreased to expand the permissible operating range. Figure 18 is a flow chart showing the procedure for the change process 32/44 allowable range change unit by permissible range change unit 22. In step S110, allowable range change unit 22 opens the on-off switch 84 to electrically isolate fuel cell 10 from external load 200. Then, the electrical power is supplied from the secondary battery 81 to the external charge 200. The permissible range change unit 22 causes the fuel cell 10 to stop power generation once to thereby allow moisture within the fuel cell 10 to be easily regulated. In step S120, the target moisture within the fuel cell 10 to expand the permissible operating range is acquired. Figure 19 is a graph showing an example of a moisture determination map M H d that is used by the permissible range change unit 22 in order to determine the target moisture within the fuel cell 10 in step S120. The humidity determination map M H d is shown as a descending convex decline curve when the geometric axis of the ordinates represents an accumulated current value and the geometric axis of the abscissa represents the humidity. The humidity determination map M H d is obtained in such a way that an experiment similar to the one described in figure 7 is conducted for each humidity inside the fuel cell 10 to obtain measured values and then the measured values are used to mark a combination an accumulated current and humidity value for each current density of the fuel cell 10. Figure 20A and Figure 20B are graphs to illustrate a process for determining a target moisture within the fuel cell 10 using the moisture determination map M H d in step S120. Figure 20A is a graph showing the map of the allowable range Mpa used in step S60 of figure 16. Here, it is assumed that in step S60, the accumulated current value Qe a has been measured, the current limiting density i a has determined from the permissible range map M PA and the external load 200 requires a current density i t outside the permissible operating range of the fuel cell 10. At that time, the permissible range change unit 22 determines a target humidity inside the fuel cell 10, as follows. The permissible range change unit 22 determines an accumulated current value Qe t that is higher by a predetermined predetermined value than the currently measured accumulated value of current Qe a as the limit value of the expanded permissible operating range. Then, the moisture determination map M H d corresponding to the required current density is selected from the moisture determination maps M H d prepared for respective current densities, and then the selected moisture determination map M HD is used to acquire a humidity h corresponding to the accumulated value of the current Qe t as a target humidity (figure 20B). In step S130 (figure 18), the permissible range change unit 22 performs the 33/44 control, so that the humidity inside the fuel cell 10 matches the target humidity acquired in step S120. Specifically, the permissible range change unit 22 increases the rotational speed of the air compressor 32 of the cathode gas supply unit 30 (figure 1) to increase the amount of air supplied to the fuel cell 10 and to decrease the amount of humidification of the air supplied by the humidification unit 35. By doing so, the interior of the fuel cell 10 can be cleaned by the supplied air from which the humidity is reduced, and the humidity inside the fuel cell 10 can be decreased. Note that the permissible range change unit 22 determines whether the humidity within the fuel cell 10 has reached the target humidity based on the value measured by the impedance measurement unit 93. Figure 20C is a graph to illustrate the process of changing the map of the allowable range M PA in step S140. Figure 20C is a graph showing the altered permissible range map M PA . Note that, in figure 20C, the curve indicating the pre-changed permissible range map M PA is shown by the dashed line and the permissible operating range is indicated by hatches. Here, in the fuel cell system 100B according to the third modality, the permissible range map M PA for each humidity inside the fuel cell 10 is prepared in advance and is stored in the control unit 20. The range change unit permissible range 22 selects the map of the permissible range M PA corresponding to the target humidity acquired in step S120 from among the maps of the permissible range M PA for respective humidity as a new map of the permissible range M PA . In the current restriction process after the humidity inside the fuel cell 10 has been decreased, the new map of the permissible range selected M PA is used. Note that the new allowable range map M PA has selected the allowable range of operation expanded, then T i current density required of the external load 200 is included in the allowable operating range. In step S150 (figure 18), the permissible range change unit 22 starts fuel cell 10, and closes on-off switch 84 (that is, activates on-off switch 84) to electrically connect the fuel cell 10 on external load 200. In step S160, while the fuel cell 10 is stopped, it is determined whether the negative voltage cell 11 has recovered from the negative voltage. When the negative voltage cell 11 recovers from the negative voltage, the normal operating control (step S5 of figure 16) of the fuel cell 10 is resumed. On the other hand, when the negative voltage cell 11 has not recovered from the negative voltage, the process returns to step S50 and then begins the current restriction process using the new permissible range map selected and changed M PA . In this way, the 100B fuel cell system according to the third 34/44 modality is able to expand the permissible operating range of the fuel cell 10 in the current restriction process by regulating the humidity inside the fuel cell 10. Thus, with the 100B fuel cell system according to the third modality , it is also possible to safely supply the electrical power corresponding to an external load 200 request while suppressing the deterioration of the performance and the degradation of the fuel cell due to the negative voltage. In the following, a fourth modality will be described. Figure 21A and Figure 21B are graphs to illustrate the process of changing the permissible range in a fuel cell system according to the fourth embodiment of the invention. Note that the configuration of the fuel cell system according to the fourth modality is similar to that of the fuel cell system according to the third modality. However, in the fuel cell system according to the fourth embodiment, the fuel cell 10 is operated in a state where the humidity within the fuel cell 10 is kept constant. Figure 21A is a graph showing a variation in the correlation between the accumulated current value and the current density in a permissible period of power generation when the temperature of the fuel cell 10 is varied, as in the case of the figure 17. The solid line in figure 21A was obtained in such a way that an experiment similar to the experiment conducted in order to obtain the graph of figure 7 is conducted in the state where the temperature of the fuel cell 10 is decreased. The curve showing the correlation between an accumulated current value and a current density shifted upward when the temperature of the fuel cell 10 was decreased. This is because the progress of the reaction expressed by the reaction formula (3) described in the third modality becomes gentle because of a decrease in the temperature of the fuel cell 10. Thus, by decreasing the operating temperature of the fuel cell 10, as in the case described in the third embodiment, it is possible to expand the permissible operating range of the fuel cell 10 in the current restriction process. Here, an experiment similar to the one described in figure 7 is conducted with a different operating temperature of the fuel cell 10, and the correlation between the accumulated current value and the current density is obtained for each operating temperature of the fuel cell. 10 in advance to make it possible to obtain the map of the permissible range M PA in this way for each fuel cell operating temperature 10. In addition, it is possible to obtain a map for determining the operating temperature M T d for each current density, which shows the correlation between the accumulated current value and the operating temperature of the fuel cell 10 based on the experimental data . Figure 21B shows an example of the temperature determination map 35/44 operation M T d at a current density in a graph of which the geometric axis of the ordinates represents an accumulated current value and the geometric axis of the abscissa represents an operating temperature of the fuel cell 10. In the fuel cell system according to the fourth modality, the map of the permissible range M PA for each operating temperature of the fuel cell 10 and the map of determining the operating temperature M T d for each current density are stored in the control unit 20 in advance. Then, the process of changing the permissible range described in the third modality is performed using these maps M PA and M T d by regulating the operating temperature of the fuel cell 10 instead of regulating the humidity inside the fuel cell 10. Note that the The operating temperature of the fuel cell 10 can be regulated in such a way that the rotational speed of the refrigerant circulation pump 73 of the refrigerant supply unit 70 is controlled to change the cooling efficiency of the refrigerant. Thus, with the fuel cell system according to the fourth modality, as in the case of the fuel cell system according to the third modality, it is still possible to safely supply the electric power corresponding to an external load request 200 , while suppressing performance deterioration and degradation of the fuel cell 10 due to negative voltage. In the following, a fifth modality will be described. Figure 22 is a flowchart showing the procedure for a negative voltage recovery process performed on a fuel cell system according to the fifth embodiment of the invention. Figure 22 is substantially the same as in Figure 12, except that a refrigerant control process from step S68 is added. Note that the configuration of the fuel cell system according to the fifth modality is similar to that of the fuel cell system 100b according to the second alternative modality to the first modality (figure 1, figure 11). Note that in the fuel cell system according to the fifth mode, when the outside air temperature or the temperature of the fuel cell 10 is below zero or when the system starts, the refrigerant is filled from the refrigerant supply unit. 70 for fuel cell 10 at a minimum constant flow rate at which degradation of fuel cell 10 is suppressed. Here, in order to recover from a state where negative voltage is generated because of freezing in the flow passages of the reaction gas of the fuel cell 10, the operating temperature of the fuel cell 10 is desirably induced to reach above zero to eliminate the frozen state. However, when the current restriction process is performed, the generation of heat from the fuel cell 10 is suppressed by the amount that the production current of the fuel cell 10 is restricted (law of 36/44 Joule). Therefore, in this case, it is difficult to increase the operating temperature of the fuel cell 10. So, in the fuel cell system according to the fifth modality, when the current restriction process is performed in a low temperature environment, such as below zero, the refrigerant control process of step S68 is performed to facilitate an increase in fuel cell operating temperature 10. Figure 23 is a flowchart showing the procedure for the refrigerant control process of step S68. The refrigerant control process can be performed every time the current restriction process is performed at the time of starting the fuel cell system. In addition, the refrigerant control process can be performed when the operating temperature of the fuel cell 10, obtained based on the values measured by the refrigerant temperature measurement units 74 and 75, is below zero or when the refrigerant temperature external air is below zero. In step S200, the control unit 20 acquires an estimated thermal value (hereinafter referred to as “estimated thermal value Qe”) when the fuel cell 10 is induced to generate electrical power for a predetermined power generation duration t (for approximately 10 to 30 seconds) at a restricted current density obtained from a limit current density. Specifically, the control unit 20 can calculate the estimated thermal value Qe using the mathematical expression (4) based on Joule's law. Qe = l 2 xRxt (4) Here, I is a restricted current density and R is a constant that is pre-established based on the internal resistance of the fuel cell 10. Note that the control unit 20 can acquire an estimated thermal value corresponding to a restricted current density based on on the map or table obtained through an experiment, or similar, in advance instead of the mathematical expression (4) above. In step S210, the control unit 20 acquires an assumed thermal capacity Cc of the fuel cell 10 when the refrigerant is circulated in the fuel cell 10 by the refrigerant supply unit 70. Here, the “assumed thermal capacity Cc of the fuel cell 10 ”is a value corresponding to an amount of heat by which the temperature of the fuel cell 10 is increased by 1 ° C. Incidentally, when the refrigerant is circulated in the fuel cell 10, the thermal amount required to increase the temperature of the fuel cell 10 varies depending on the temperature of the fuel cell 10 or the temperature and flow rate of the refrigerant. As described above, in the fuel cell system according to the fifth embodiment, the refrigerant is supplied to the fuel cell 10 at a pre-established minimum constant flow rate. Then, in the fuel cell system according to the fifth modality, the control unit 20 pre-stores a map or tab37 / 44 It is capable of determining only the assumed thermal capacity Cc corresponding to the temperature of the refrigerant and the temperature of the fuel cell 10, and uses the map or table to acquire the assumed thermal capacity Cc. In step S220, the control unit 20 uses the estimated thermal value Qe acquired in step S200 and the assumed thermal capacity Cc of the fuel cell 10, acquired in step S210, to calculate an estimated temperature Te which is a predicted temperature of the fuel cell fuel 10 after the predetermined power generation duration t. Specifically, the estimated temperature Te can be calculated using the following mathematical expression (5). Qe = Ccx (Te-Tm) (5) Here, Tm is a measured operating temperature of the fuel cell current 10. In step S230, control unit 20 determines whether the estimated temperature Te calculated in step S220 is lower than or equal to a predetermined threshold. Here, the predetermined threshold can be adjusted at a temperature (for example, 0 0 C) at which the frozen state in the reaction gas flow passages of fuel cell 10 begins to be eliminated. When the estimated temperature Te is higher than the predetermined threshold, the control unit 20 performs the processes in step S70 and in the following steps of the current restriction process (figure 22) while continuing to supply the refrigerant to the fuel cell 10 on the assumption that the operating temperature of the fuel cell 10 reaches the target value in a predetermined power generation duration t. On the other hand, when the estimated temperature Te is lower than or equal to the predetermined threshold, the control unit 20 for supplying and circulating the refrigerant to the fuel cell 10 in order to facilitate an increase in the temperature of the fuel cell fuel 10 in the predetermined power generation duration t (step S240). Here, in the fuel cell system according to the fifth embodiment, as described above, the refrigerant is supplied to the fuel cell 10 even when the temperature of the fuel cell 10 is low, such as when the system is started . This is because of the following reason. That is, at the time of starting the system, or similar, because of the blocking of gas flow passages within the fuel cell 10, it is highly likely that the amount of electrical power generated will become non-uniform between the generating elements. force 11 of the fuel cell 10 or between the power generation regions of each power generation element 11. When the supply of refrigerant to the fuel cell 10 is stopped while a power generation distribution within the fuel cell 10 is non-uniform, the power generating element 11 or the region that generates a relative quantity 38/44 of electrical power can degrade locally because of the heat generation resulting from the generation of power. In order to avoid local degradation of the fuel cell 10 due to the non-uniform amount of the thermal value, even when the temperature of the fuel cell 10 is low, the refrigerant is desirably supplied to the fuel cell 10. However, when the current restriction process is performed, the thermal value of the fuel cell 10 is restricted, so the thermal value is relatively small in a portion in which the amount of electrical power generated increases locally in the fuel cell 10. Thus , as in the case of step S240, even while the supply of refrigerant to the fuel cell 10 is stopped during the current restriction process, the degradation of the fuel cell 10 is less likely to occur because of the non-uniform thermal value as described above. Therefore, by stopping the refrigerant supply, it is possible to facilitate an increase in the temperature of the fuel cell 10 without degradation of the fuel cell 10. After the refrigerant supply to the fuel cell 10 is stopped in step S240, the control unit 20 performs the processes in step S270 and in the following steps of the current restriction process (figure 22). Note that when the negative voltage cell 11 recovers from the negative voltage and normal operation of the fuel cell 10 is resumed, the control unit 20 restarts the refrigerant supply to the fuel cell 10. In this way, with the fuel cell system according to the fifth modality, even when the negative voltage occurs in the fuel cell 10 and the current restriction process is performed, the refrigerant supply to the fuel cell 10 is controlled appropriately to facilitate the increase in the operating temperature of the fuel cell 10. Thus, the recovery of the negative voltage state is facilitated with the increase in the temperature of the fuel cell 10. In the following, a sixth modality will be described. Figure 24 is a flow chart showing the procedure for a negative voltage recovery process performed on a fuel cell system according to the sixth embodiment of the invention. Figure 24 is substantially the same as Figure 22, except that step S68F is provided instead of step S68. Note that the configuration of the fuel cell system according to the sixth modality is similar to the configuration of the fuel cell system described in the fifth modality (figure 1, figure 11). Note that, in the fuel cell system according to the sixth modality, the control unit 20 measures and records the operating temperature of the fuel cell 10 periodically (for example, at an interval of one second). In the fuel cell system according to the sixth modality, when the 39/44 current restriction process is performed while the system starts or fuel cell temperature 10 is low (for example, temperature is at or below 0 ° C), the first or second refrigerant control process is performed after step S62 (step S68F). Specifically, in step S68F after the current restriction process is started, the first refrigerant control process is performed. Then, through the steps of the current restriction process, when a predetermined condition is satisfied at the time when step S68F is executed again, the second refrigerant control process is performed. Figure 25A is a flow chart showing the procedure for the first refrigerant control process. Figure 25A is substantially the same as Figure 23. That is, the first refrigerant control process is performed in a manner similar to that of the refrigerant control process described in the fifth embodiment. In the first refrigerant control process, when it is determined in step S230 that it is difficult for the operating temperature of the fuel cell 10 to reach the target operating temperature through the current restriction process, the supply of the refrigerant to the fuel cell 10 is stopped (step S240). Figure 25B is a flow chart showing the procedure for the second refrigerant control process. The second refrigerant control process is carried out when the refrigerant supply to the fuel cell 10 is not stopped in the first refrigerant control process. In step S250, the control unit 20 calculates the rate of increase (dT / dt) in the operating temperature T, which is the rate of change in time in the operating temperature T of the fuel cell 10, based on the operating temperature recorded from the fuel cell 10. In step S260, the control unit 20 calculates an estimated time t until the operating temperature T of the fuel cell 10 reaches a target operating temperature (for example, 0 0 C) based on the rate of increase calculated at the operating temperature. operation T. In step S270, the control unit 20 performs the determination process using the estimated time te. When the estimated time is longer than a predetermined threshold (for example, 30 seconds), the control unit 20 determines that the operating temperature of the fuel cell 10 does not reach the target operating temperature within a period of time predetermined in the state where refrigerant supply continues, and then for refrigerant supply to fuel cell 10 (step S280). On the other hand, when the estimated time is shorter than or equal to the predetermined threshold, the control unit 20 determines that the operating temperature of the fuel cell 10 can reach the target operating temperature within the predetermined time period even when the refrigerant supply to the 40/44 fuel 10 continues. Then, the control unit 20 continuously performs the current restriction process (figure 22) while continuing to supply the refrigerant to the fuel cell 10. Here, in the first refrigerant control process, even when it is determined that the operating temperature of the fuel cell 10 reaches the target temperature within a predetermined power generation duration even when the refrigerant supply continues, the operating temperature can not increase than predicted because the production of electrical power from the fuel cell 10 is restricted. However, with the fuel cell system according to the sixth modality, in the second refrigerant control process, it is again determined whether the supply of the refrigerant to the fuel cell 10 continues based on the rate of change in time at the temperatures of operation actually measures the fuel cell 10. So when the current restriction process is performed while the system starts or the temperature of the fuel cell 10 is low, the refrigerant supply control is still performed properly, so an increase in temperature of the fuel cell 10 is facilitated and the recovery of the negative voltage state is facilitated. Figure 26A and Figure 26B are graphs showing the results of the experiments conducted by the inventors of the invention as reference examples of the invention. Figure 26A and Figure 26B are graphs showing the change in time in the negative voltage cell temperature (cell temperature) and a change in time in the current density of the fuel cell when one of the single cells in the fuel cell is induced to generate negative voltage in a low temperature environment below zero. Figure 26A shows the case where the production of electric power from the fuel cell is restricted to a substantially constant low current density. Figure 26B shows the case where the current density is gradually increased. Note that the scale of each of the geometric axis of the ordinates and the geometric axis of the abscissa of figure 26A and figure 25B is equal to each other. Here, the negative voltage in part of the single cells of the fuel cell can possibly occur because the water content that remains in the flow passages of the reaction gas provided in the part of the single cells freezes in a low temperature environment and then the gas flow are blocked. In such a case, it is desirable that the temperature of the fuel cell be increased to defrost the frozen water content in the gas flow passages to thereby eliminate the scarce supply of the reaction gas, thereby recovering from the negative voltage. As shown in the graphs in figure 26A and figure 26B, an increase in cell temperature is more moderate when the fuel cell is induced to produce electrical force at a constant low current density than when the combustion cell 41/44 is induced to produce electrical force at a higher current density than the constant low current density. Thus, when negative voltage is generated, the fuel cell is desirably induced to produce electrical force at a high current density as much as possible to thereby increase the operating temperature of the fuel cell in a short period of time. In the current restriction process when negative voltage is generated, described in the above modalities, the current density is decreased in a gradual way along the downward convex curve that shows the map of the permissible range M PA with an increase in the accumulated current value . By doing this, fuel cell 10 can be operated near a permissible limit current density in the permissible operating range, so it is possible to increase the temperature of fuel cell 10 in an additional short period of time in a low temperature environment , then it is easy to recover from negative tension. That is, this is more desirable in the case of the current restriction process according to the above modalities than when the current is restricted to a constant low current density when negative voltage is generated. Note that the aspect of the invention is not limited to the examples or modalities above, the aspect of the invention can be carried out in various forms without departing from the scope of the invention. For example, the following first to thirteenth alternative modalities are possible. First, the first alternative modality will be described. In the modalities described above, the control unit 20 stores, as the map of the permissible range Mpa, the correlation between permissible accumulated current values for fuel cell 10 and permissible current densities for fuel cell 10 in a period during the which negative voltage is generated. However, the correlation does not need to be stored as a map; instead, for example, the correlation can be stored as an arithmetic expression or a function. In the following, the second alternative modality will be described. In the modalities described above, the correlation between cumulative current permissible values for fuel cell 10 and permissible current densities for fuel cell 10 in a period during which the negative voltage is generated is adjusted in the permissible range map Mpa as defined by the convex decline curve. However, the correlation can be adjusted on the map of the allowable range M PA as defined by a curve having another shape. For example, the correlation can be adjusted on the map of the allowable range M PA as defined by a linear line that declines linearly. However, the downward convex decline curve that defines the map of the permissible range M PA in the above modalities is based on the experiment conducted by the inventors of the invention, and is more desirable as a graph that defines the permissible range of operation over a period during which the ten42 / 44 is negative is generated. In the following, the third alternative modality will be described. In the above described modalities, in the current restriction process of the negative voltage recovery process, the current density of the fuel cell 10 is gradually decreased along the downward convex curve that defines the permissible range map M PA with the increase in the accumulated current value. However, in the current restriction process, the current density of the fuel cell 10 may not be decreased in a gradual manner along the downward convex curve. The current density of the fuel cell 10 only needs to be controlled so that it falls within the permissible operating range that is defined in the permissible range map M PA . However, as in the case of the above modalities, the current density of the fuel cell 10 is most desirably decreased in a gradual manner along the downward convex curve because it is possible to perform the control at a current density closer to a current density. allowable limit in the current restriction process. In the following, the fourth alternative modality will be described. In the above-described embodiments, the cell voltage measurement unit 91 measures the voltages of all the power generating elements 11 of the fuel cell 10 to thereby detect the negative voltage. However, the cell voltage measurement unit 91 does not need to measure the voltages of all power generating elements 11; the cell voltage measurement unit 91 only needs to measure the voltage of at least one of the power generating elements 11 in order to detect the negative voltage in this way. For example, it is known that the negative voltage is highly likely to occur in the power generating element 11 disposed in the end portion of the fuel cell 10, in which the operating temperature tends to be the lowest among the generating elements. of force 11. Then, the voltage measurement unit of cell 91 can measure the voltage of only the power generating element 11 disposed in the end portion to detect the negative voltage. Next, the fifth alternative modality will be described. In the first mode, the minimum current density i | ) m is set as a minimum limit current density of the fuel cell 10 in the current restriction process, and the control unit 20 performs the process of restarting the fuel cell 10 using the minimum current density inm as a threshold. However, the minimum current density hm may not be adjusted in the control unit 20. Next, the sixth alternative modality will be described. In the third or fourth embodiment, one of the humidity within the fuel cell 10 and the operating temperature of the fuel cell 10 is regulated to perform the process of expanding the permissible operating range. However, it is also applicable that both the humidity inside the fuel cell 10 and the operating temperature of the fuel cell 10 are regulated. 43/44 to expand the permissible operating range. In this case, it is desirable that a map of the permissible range M PA be prepared for each combination of the humidity within the fuel cell 10 and the operating temperature of the fuel cell 10. In the following, the seventh alternative modality will be described. In the third or fourth mode, the permissible range change unit 22 selects the map corresponding to the humidity inside the fuel cell 10 or the operating temperature of the fuel cell 10 from among the maps of the permissible range M PA prepared in advance for each moisture within fuel cell 10 or each operating temperature of fuel cell 10 to expand the permissible operating range. However, the permissible range change unit 22 may use a pre-established arithmetic expression, algorithm or the like, to correct the correlation adjusted in the permissible range map M pa in response to moisture within the fuel cell 10 or the cell's operating temperature. 10 to expand the permissible operating range in this way. In the following, the eighth alternative modality will be described. In the above described modalities, the correlation between current densities of the fuel cell 10 and accumulated current values of the fuel cell 10 is adjusted in the map of the permissible range M pa . However, the correlation between current values, instead of current densities, of fuel cell 10 and cumulative current values of fuel cell 10 can be adjusted on the map of the allowable range M PA . The current value of the fuel cell 10 is obtained by multiplying the current density by the electrode area, so the correlation between current values of the fuel cell 10 and accumulated current values of the fuel cell 10 can also be considered as a type correlation between current densities of fuel cell 10 and cumulative current values of fuel cell 10. In the following, the ninth alternative modality will be described. In fuel cell systems according to the modalities described above, when the negative voltage cell does not recover from the negative voltage after the amount of gas from the fueled cathode is increased, it is determined that the negative voltage is generated because of the supply hydrogen and then the current restriction process is performed. However, it is also applicable that the current restriction process is started after the negative voltage has been detected without performing the negative voltage recovery process by increasing the amount of gas from the supplied cathode. In the following, the tenth alternative modality will be described. In fuel cell systems according to the modalities described above, the process for recovering the negative voltage is started when the negative voltage is detected and the current restriction process is performed in this process. However, it is also applicable that in the system 44/44 fuel cell system, the current restriction process is performed when a pre-established environmental condition that indicates a possibility that the negative voltage will be generated is satisfied even when the negative voltage has not been detected. For example, the current restriction process described in the above modalities can be performed under an environment where the temperature of the outside air is at or below zero, when the temperature of the fuel cell 10 is close to a temperature at or below zero, or similar. In addition, the warning process (step S63 of figure 12), the process of changing the permissible range (step S65 of figure 16) or the refrigerant control process (step S68 of figure 22, step S68F of figure 24) of according to the current restriction process can be performed. In the following, the eleventh alternative modality will be described. In the second, third or fourth modality described above, as described in another example of configuring the first modality, the accumulated current value can be recorded non-volatile in the unit for recording the accumulated current value 23. In addition, when the cumulative current limit value is greater than or equal to a predetermined threshold or when the restricted current density is less than or equal to a predetermined threshold, the warning process can be performed by the warning unit 25. In the following, the twelfth alternative modality will be described. In the fifth embodiment described above, it is determined whether to continue supplying the refrigerant based on the estimated thermal value Qe or the estimated temperature Te of the fuel cell 10, calculated using the assumed thermal capacity Cc. Instead, the control unit 20 can control the flow rate of the refrigerant supplied to the fuel cell 10 based on the operating temperature of the fuel cell 10 and the estimated thermal value Qe. That is, the control unit 20 can decrease the flow rate of the filled refrigerant to the fuel cell 10 as the estimated thermal value Qe decreases and can decrease the degree of decrease in the flow rate of the filled refrigerant as the operating temperature of fuel cell 10 increases. In the following, the thirteenth alternative modality will be described. In the fifth embodiment described above, the control unit 20 uses the map or table prepared in advance to acquire an assumed thermal capacity Cc corresponding to the temperature of the fuel cell 10 and the temperature of the refrigerant. However, the control unit 20 may have an assumed thermal capacity Cc as a constant that is irrelevant to the temperature of the fuel cell 10 or the temperature of the refrigerant. In that case, the assumed thermal capacity Cc can be adjusted as the sum (CFC + CRE) of the total CFC of the thermal capacities of the components of the fuel cell 10 and the thermal capacity CRE of a constant amount of refrigerant present inside the fuel cell 10 .
权利要求:
Claims (20) [1] 1. Fuel cell system that produces electrical power in response to a negative influence on the γόγπο civíorno ^ ΔΡΔ ^ ΤΕΡΙ7ΑΓΊΛΊί noIn fo + n rio mio nomoroonrlô 'QVIIUIlUyUV UV Ml I 114 OL4I yu VALVI I IU) I pçziw4LV / ULz Wl I 1I X ^ Vrl IMV. a fuel cell (10) that has at least one power generating element (11); a negative voltage detection unit (91) that is configured to detect negative voltage in at least one power generating element; a control unit (20) that is configured to control the production of electrical power from the fuel cell (10); and an accumulated current value measurement unit (21) which is configured to measure an accumulated current value that is obtained by integrating the fuel cell current production time (10), in which the control unit (21 ) is configured to pre-store a correlation between accumulated current values that are permissible in a period during which negative voltage is generated in at least one power generation element (11) and current densities that are permissible in the period and when the negative voltage is detected in at least one power generation element (11), the control unit (20) is configured to perform the production restriction process to restrict the production of the electric power from the fuel cell (10) 1, in order to fall within a permissible operating range defined by the cumulative permissible current values and permissible current densities of the correlation. [2] 2. Fuel cell system, according to claim 1, CHARACTERIZED by the fact that: when the correlation is shown by a graph of which a first geometry axis represents an accumulated current value of the fuel cell (10) and a second geometry axis represents a current density of the fuel cell (10), the correlation is shown as a downward convex curve in which the allowable current density decreases as the accumulated allowable current value increases. [3] 3. Fuel cell system, according to claim 2, CHARACTERIZED by the fact that: in the production restriction process, the control unit (20) is configured to decrease the current density of the fuel cell (10) along the downward convex curve, which indicates maximum values of permissible current densities, with an increase in accumulated current value. [4] 4. Fuel cell system according to any one of claims 1 to 3, CHARACTERIZED by the fact that it still comprises: an operating state regulation unit that is configured to include 2/7 at least one of a humidification unit (35) which controls the amount of humidification of the reaction gas supplied to the fuel cell (10) in order to regulate the wet state within the. fuel cell (10) and a refrigerant supply unit (70) which controls the flow rate of the refrigerant supplied to the fuel cell (10) in order to regulate the operating temperature of the fuel cell (10); and a correlation change unit that is configured to change the correlation in response to at least one of the wet state within the fuel cell (10) and the operating temperature of the fuel cell (10), where when the density of current corresponding to a required production current of the external load in a period during which the negative voltage is generated in at least one power generating element (11) is greater than a predetermined value, the control unit (20) is configured to cause the operating state regulation unit to regulate at least one of the wet state inside the fuel cell (10) and the operating temperature of the fuel cell (10), in order to expand the permissible operating range in such a way that the correlation is altered by the correlation change unit. [5] 5. Fuel cell system according to any one of claims 1 to 4, CHARACTERIZED by the fact that: when the production restriction process is complete, the control unit (20) is configured to store non-volatile an accumulated current value of the fuel cell current production (10) in the production restriction process and, when the production restraint process is resumed, the control unit (20) is configured to perform the production restraint process using a total current accumulated value that is obtained by adding the stored current accumulated value and an accumulated current value of the current production of the fuel cell (10) after the production restriction process is resumed. [6] 6. Fuel cell system according to any one of claims 1 to 5, CHARACTERIZED by the fact that it still comprises: a warning unit (25) that is configured to warn a user about fuel cell degradation (10), where: the control unit (20) is configured to pre-store a lower limit value of the current density of the fuel cell (10) and, when the current density of the fuel cell (10) is lower than the limit value lower in the production restriction process, the control unit (20) is configured to cause the warning unit (25) to warn the user about fuel cell degradation (10). [7] 7. Fuel cell system according to any one of claims 1 to 6, CHARACTERIZED by the fact that it still comprises: 3/7 a refrigerant supply unit (70) which is configured to supply refrigerant to the fuel cell (10) to control the temperature of the fuel cell (10); and a temperature measurement unit that is configured to measure the operating temperature of the fuel cell (10), where: in the production restriction process, the control unit (20) is configured to obtain an estimated thermal value which is a thermal value of the fuel cell (10) when the fuel cell (10) is induced to produce the electrical force in a current density based on a current density control value for the fuel cell (10), and control the amount of refrigerant supplied to the fuel cell (10) by the refrigerant supply unit (70) based on operating temperature measured by the temperature measuring unit and the estimated thermal value. [8] 8. Fuel cell system, according to claim 7, CHARACTERIZED by the fact that: in the production restriction process, the control unit (20) is configured to use the estimated thermal value and the operating temperature measured by the temperature measurement unit to calculate an estimated temperature rise in the fuel cell (10) when the fuel cell (10) is induced to produce electrical power for a predetermined period of time while the fuel cell (10) is being supplied with refrigerant and, when the estimated temperature rise is less than or equal to a pre-established threshold , the control unit (20) is configured to cause the fuel cell (10) to generate electrical power in a state where the refrigerant supply unit (70) is induced to stop supplying the refrigerant to the fuel cell (10 ). [9] 9. Fuel cell system, according to claim 8, CHARACTERIZED by the fact that: in the production restriction process, when a rate of increase in the operating temperature of the fuel cell (10) is less than a pre-established threshold, the control unit (20) is configured to make the fuel cell (10) generate electrical force in the state where the refrigerant supply unit (70) is induced to stop the refrigerant supply to the fuel cell (10). [10] 10. Control method for a fuel cell system that produces electrical power generated by a fuel cell having at least one power generating element in response to a request for an external load, CHARACTERIZED by the fact that it comprises: detecting the negative voltage in at least one force generating element (11); measure the accumulated current value that is obtained by the time integration of the 4/7 current reduction of the fuel cell (10) in a period during which the negative voltage is generated in at least one power generating element (11); consult a pre-established correlation between accumulated current values that are permissible in the period during which negative voltage is generated in at least one power generation element (11) and current densities that are permissible in the period; and carrying out the production restriction process to restrict the production of the electric power of the fuel cell (10), so as to fall within a permissible operating range defined by the cumulative permissible current values and permissible current densities of the correlation. [11] 11. Fuel cell system that produces electrical power generated in response to a request for an external load, CHARACTERIZED by the fact that it comprises: a fuel cell (10) that has at least one power generating element (11); a control unit (20) that is configured to control the production of electrical power from the fuel cell (10); an accumulated current value measurement unit (21) that is configured to measure the accumulated current value that is obtained by integrating the fuel cell current production time (10), in which: the control unit (20) is configured to pre-store a correlation between accumulated current values that are permissible in a period during which negative voltage is generated in at least one power generation element (11) and current densities that are permissible in the period and when a pre-established environmental condition indicating a possibility that the negative voltage is generated is satisfied, the control unit (20) is configured to determine that the negative voltage is generated in at least one power generating element (11) and then execute the production restriction process to restrict the production of the electric power of the fuel cell (10), so that it falls within a permissible operating range defined by the cumulative permissible current values and permissible current densities correlation. [12] 12. Fuel cell system, according to claim 11, CHARACTERIZED by the fact that: when the correlation is shown by a graph of which the first geometry axis represents an accumulated current value of the fuel cell (10) and the second geometry axis represents the current density of the fuel cell (10), the correlation is shown as a downward convex curve in which the allowable current density decreases as the cumulative allowable current value increases. 5/7 [13] 13. Fuel cell system according to claim 12, CHARACTERIZED by the fact that: in the production restriction process, the control unit (20) is configured to decrease the current density of the fuel cell (10) along the downward convex curve, which indicates maximum values of permissible current densities, with an increase in accumulated current value. [14] 14. Fuel cell system according to any of claims 11 to 13, CHARACTERIZED by the fact that it still comprises: an operating state regulation unit which is configured to include at least one of a humidification unit (35) which controls the amount of humidification of the reaction gas supplied to the fuel cell (10) in order to regulate the wet state inside the fuel cell (10) and a refrigerant supply unit (70) that controls the flow rate of the refrigerant supplied to the fuel cell (10) in order to regulate the operating temperature of the fuel cell (10) ; and a correlation change unit that is configured to change the correlation in response to at least one of the wet state within the fuel cell (10) and the operating temperature of the fuel cell (10), where: when a current density corresponding to a required production current of the external load in a period during which the negative voltage is generated in at least one power generating element (11) is greater than a predetermined value, the control unit (20) is configured to make the regulating unit of the regular operating state at least one of the wet state inside the fuel cell (10) and the operating temperature of the fuel cell (10), in order to expand the range of permissible operation in such a way that the correlation is altered by the correlation change unit. [15] 15. Fuel cell system according to any of claims 11 to 14, CHARACTERIZED by the fact that: when the production restriction process is complete, the control unit (20) is configured to store non-volatile an accumulated current value of the fuel cell current production (10) in the production restriction process and, when the production restriction process is resumed, the control unit (20) is configured to execute the production restriction process using a total current accumulated value that is obtained by adding the stored current accumulated value and the current accumulated value of the current production of the fuel cell (10) after the production restriction process is resumed. [16] 16. Fuel cell system according to any of claims 11 to 15, CHARACTERIZED by the fact that it still comprises: 6/7 a warning unit (25) that is configured to warn a user about fuel cell degradation (10), where the control unit (20) is configured to pre-store a lower density limit value current of the fuel cell (10) and, when the current density of the fuel cell (10) is lower than the lower limit value in the production restriction process, the control unit (20) is configured to make the warning unit (25) warns the user of fuel cell degradation (10). [17] 17. Fuel cell system according to any of claims 11 to 16, CHARACTERIZED by the fact that it still comprises: a refrigerant supply unit (70) which is configured to supply refrigerant to the fuel cell (10) to thereby control the temperature of the fuel cell (10); and a temperature measurement unit that is configured to measure the operating temperature of the fuel cell (10), in which in the production restriction process, the control unit (20) is configured to obtain an estimated thermal value which is a thermal value of the fuel cell (10) when the fuel cell (10) is induced to produce electrical force at a current density based on a current density command value for the fuel cell (10) and control the quantity of the refrigerant supplied to the fuel cell (10) by the refrigerant supply unit (70) based on the operating temperature measured by the temperature measuring unit and the estimated thermal value. [18] 18. Fuel cell system, according to claim 17, CHARACTERIZED by the fact that: in the production restriction process, the control unit (20) is configured to use the estimated thermal value and the operating temperature measured by the temperature measurement unit to calculate an estimated temperature rise in the fuel cell (10) when the fuel cell (10) is induced to produce electrical power for a predetermined period of time while the fuel cell (10) is being supplied with refrigerant and, when the estimated temperature rise is less than or equal to a pre-established threshold , the control unit (20) is configured to cause the fuel cell (10) to generate electrical power in a state where the refrigerant supply unit (70) is induced to stop supplying the refrigerant to the fuel cell (10 ). [19] 19. Fuel cell system, according to claim 18, CHARACTERIZED by the fact that: in the production restriction process, when a rate of increase in the operating temperature of the fuel cell (10) is less than a pre-established threshold, the in control unit (20) is configured to make the fuel cell (10) generate electrical power in a state where the refrigerant supply unit (70) is induced to stop the refrigerant supply to the fuel cell (10). [20] 20. Control method for a fuel cell system that produces power 5 electrical generated by a fuel cell having at least one power generating element (11) in response to a request for an external load, CHARACTERIZED by the fact that it comprises: measure an accumulated current value that is obtained by integrating the fuel cell current production time (10) over a period during which a pre-established environmental condition that indicates a possibility that the negative voltage is generated in at least one element power generation (11) is satisfied; consult a pre-established correlation between accumulated current values that are permissible in the period during which the negative voltage is generated in at least one power generation element (11) and current densities that are permissible in the period; and carrying out the production restriction process to restrict the production of the electric power of the fuel cell (10), so as to fall within a permissible operating range defined by the cumulative permissible current values and permissible current densities of the correlation.
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公开号 | 公开日 AU2011259799B2|2013-07-11| CN102986071A|2013-03-20| CN102986071B|2015-04-15| BR112012030022A2|2016-08-02| WO2011148265A1|2011-12-01| JP4998609B2|2012-08-15| KR20120136387A|2012-12-18| RU2012149572A|2014-06-27| JP2012009406A|2012-01-12| CA2787473C|2014-09-16| RU2531504C2|2014-10-20| ES2610552T3|2017-04-28| US20130059215A1|2013-03-07| AU2011259799A1|2012-07-19| EP2577783B1|2016-10-12| KR101361881B1|2014-02-12| US9196915B2|2015-11-24| EP2577783A1|2013-04-10| CA2787473A1|2011-12-01|
引用文献:
公开号 | 申请日 | 公开日 | 申请人 | 专利标题 US7727663B2|2001-07-18|2010-06-01|Tel-Aviv University Future Technology Development L.P.|Fuel cell with proton conducting membrane and with improved water and fuel management| US20050233186A1|2002-06-17|2005-10-20|Okuyama Ryoichi|Liquid-fuel fuel cell, operation monitoring method for monitoring operation thereof, and operation monitoring device| JP2005183354A|2003-11-27|2005-07-07|Nissan Motor Co Ltd|Fuel cell system| JP4930818B2|2004-07-09|2012-05-16|トヨタ自動車株式会社|Fuel cell system| JP2006179389A|2004-12-24|2006-07-06|Mitsubishi Electric Corp|Fuel cell power generating device, stopping method and stopped-state keeping method of the same| JP4772391B2|2005-06-17|2011-09-14|本田技研工業株式会社|FUEL CELL SYSTEM AND CONTROL METHOD FOR FUEL CELL SYSTEM| JP2007035516A|2005-07-28|2007-02-08|Nissan Motor Co Ltd|Fuel cell system| KR100664074B1|2005-09-28|2007-01-03|엘지전자 주식회사|Driving control method for fuel cell system| JP4978007B2|2006-01-10|2012-07-18|トヨタ自動車株式会社|Fuel cell system| JP2008147102A|2006-12-13|2008-06-26|Toyota Motor Corp|Fuel cell system| JP5435320B2|2007-02-09|2014-03-05|トヨタ自動車株式会社|FUEL CELL SYSTEM AND CONTROL METHOD FOR FUEL CELL SYSTEM| JP5200414B2|2007-04-26|2013-06-05|トヨタ自動車株式会社|Fuel cell system| US9118049B2|2007-05-29|2015-08-25|Toyota Jidosha Kabushiki Kaisha|Fuel cell system| JP5155734B2|2008-05-19|2013-03-06|本田技研工業株式会社|Fuel cell system and operation method thereof| ES2382770T3|2008-07-28|2012-06-13|Siemens Aktiengesellschaft|Procedure for cleaning at least one inlet channel for operating gas of a fuel cell from a fuel cell arrangement and fuel cell arrangement|JPS6216403B2|1982-11-17|1987-04-13|Furukawa Denki Kogyo Kk| JP5949946B2|2012-12-28|2016-07-13|日産自動車株式会社|Fuel cell system| KR101558740B1|2014-02-24|2015-10-07|현대자동차주식회사|Method and apparatus for diagnosing the state of fuel cell system| JP6079745B2|2014-10-27|2017-02-15|トヨタ自動車株式会社|Inspection method and manufacturing method of fuel cell| JP6131930B2|2014-10-28|2017-05-24|トヨタ自動車株式会社|Power generation monitoring device, fuel cell system, and power generation monitoring method| JP6314799B2|2014-11-13|2018-04-25|トヨタ自動車株式会社|Fuel cell system and fuel cell control method| JP6156332B2|2014-11-14|2017-07-05|トヨタ自動車株式会社|Fuel cell system and control method thereof| GB2532929B|2014-11-27|2021-09-01|Intelligent Energy Ltd|Coolant injection controller| CN106299401B|2015-05-20|2019-07-16|通用电气公司|Fuel cell system and its control method| JP6183416B2|2015-06-26|2017-08-23|トヨタ自動車株式会社|Fuel cell system| JP6569464B2|2015-10-22|2019-09-04|株式会社Ｓｏｋｅｎ|Fuel cell diagnostic device| CN105702984B|2016-01-21|2018-07-24|北京理工大学|A kind of control and electric energy collection system for low-power fuel cell| DE102016114081A1|2016-07-29|2018-02-01|Proton Motor Fuel Cell Gmbh|Fuel cell system and method for operating a fuel cell system| EP3510662B1|2016-09-08|2021-03-10|Daimler AG|Below freezing start-up method for fuel cell system| US10749194B2|2016-11-15|2020-08-18|Ford Global Technologies, Llc|Circuit and method for cell voltage sensing in fuel cell stack| KR101947888B1|2017-01-09|2019-02-14|현대자동차주식회사|Method and system for controlling supply energy of fuelcell vehicle| KR20180083552A|2017-01-13|2018-07-23|주식회사 엘지화학|A fuel cell system| CN110582879A|2017-02-18|2019-12-17|戴姆勒股份有限公司|Method for detecting and mitigating fuel starvation in a fuel cell system| JP6780593B2|2017-07-07|2020-11-04|トヨタ自動車株式会社|Fuel cell system and fuel cell system control method| US10777831B2|2017-11-28|2020-09-15|Toyota Motor Engineering & Manufacturing North America, Inc.|Equation based cooling system control strategy/method| US10714773B2|2017-11-28|2020-07-14|Toyota Motor Engineering & Manufacturing North America, Inc.|Cooling system dT/dt based control| US11094950B2|2017-11-28|2021-08-17|Toyota Motor Engineering & Manufacturing North America, Inc.|Equation based state estimator for cooling system controller| US10720655B2|2017-11-28|2020-07-21|Toyota Motor Engineering & Manufacturing North America, Inc.|Partial derivative based feedback controls for pid| US10971745B2|2018-01-10|2021-04-06|GM Global Technology Operations LLC|Cell reversal diagnostics for a fuel cell stack| RU197149U1|2019-12-18|2020-04-02|федеральное государственное бюджетное образовательное учреждение высшего образования "Московский политехнический университет" |Autonomous battery module based on lithium polymer batteries|
法律状态:
2018-04-10| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]| 2019-02-26| B06T| Formal requirements before examination [chapter 6.20 patent gazette]| 2019-10-22| B09A| Decision: intention to grant [chapter 9.1 patent gazette]| 2019-11-19| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 25/05/2011, OBSERVADAS AS CONDICOES LEGAIS. (CO) 20 (VINTE) ANOS CONTADOS A PARTIR DE 25/05/2011, OBSERVADAS AS CONDICOES LEGAIS |
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申请号 | 申请日 | 专利标题 JP2010119448|2010-05-25| JP2010226568A|JP4998609B2|2010-05-25|2010-10-06|Fuel cell system and control method thereof| PCT/IB2011/001478|WO2011148265A1|2010-05-25|2011-05-25|Fuel cell system and control method therefor| 相关专利
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