• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The system for converting thermal energy into electrical energy (SYS) comprises a frame (1), at least one temperature-sensitive element (3) held in the frame (1) by two of its ends (31, 32) between a hot source (TC) and a cold source (TF), at least one piezoelectric element (5) disposed between at least a portion of the frame (1) and at least a first of said two ends (31, 32) of said at least one a temperature sensitive element (3), said at least one temperature sensitive element (3) being configured to cyclically deform between two states under the action of the thermal gradient between the hot source (TC) and the cold source ( TF) while exerting a stress during its cyclic deformation on said at least one piezoelectric element (5) via said at least one end.
    公开号:FR3042925A1
    申请号:FR1560185
    申请日:2015-10-26
    公开日:2017-04-28
    发明作者:Arthur Arnaud；Jihane Boughaleb；Stephane Monfray；Thomas Skotnicki
    申请人:STMicroelectronics Crolles 2 SAS；
    IPC主号:
    专利说明:

    System for converting thermal energy into electrical energy.
    Embodiments of the invention relate to thermoelectric transducers, particularly in the context of recovering thermal energy produced by electronic circuits in operation.
    It is envisaged to recover this thermal energy to convert it at least partly into electrical energy.
    There are temperature-sensitive elements for converting thermal energy into mechanical energy, in particular thanks to structures having a very high ability to deform under the effect of temperature. It may be for example bimetallic blades (or bimetallic). A bimetal comprises two blades (or membranes) of metals of different alloys with different coefficients of thermal expansion, flexible, welded or glued face to face against each other.
    In the following Ksup and Kinf respectively designate the thermal coefficients of the membranes of the bimetallic strip, with Ksup> Kinf, while MKsup and MKinf respectively designate the corresponding membranes, called high expansion membrane and low expansion membrane.
    When a bimetal is heated, the MKsup high expansion membrane has a tendency to expand more than the MKinf low expansion membrane, and the bimetal bends along a radius of curvature in the direction of the MKsup membrane towards the MKinf membrane. Conversely, when a bimetal is cooled, the MKsup high-expansion membrane has a tendency to contract more than the MKinf low-expansion membrane, and the bimetal bends along a radius of curvature in the direction of the MKinf membrane towards the MKsup membrane.
    Thus, if the bimetallic is repeatedly heated and cooled, the curvature is turned over as many times. The reversals of the curvature occur according to a breakdown, the bimetal passing suddenly from a first stable position to a second stable position. This is called "bistability".
    Thus when placing a bimetallic strip between a hot source and a cold source, it oscillates from one stable position to the other cyclically. Such a cycle is illustrated in FIG.
    The curve H represents the evolution of the vertical position Z of the middle of the curvature of the bimetal with respect to a median position as a function of the temperature T, and forms a hysteresis cycle. When the bimetallic strip is heated from a first stable position 11, the curvature remains substantially constant up to a first breakdown temperature Tel, represented in point 12. At the temperature Tel, the transition from point 12 to point 13 results in the sudden reversal of the curvature. In point 13, the bimetallic strip then takes its second stable position.
    The passage from point 13 to point 14 corresponds to a decrease in the temperature of the bimetallic strip, the curvature remaining substantially constant up to point 14 at a second breakdown temperature Tc2. At the temperature Tc2, the passage from point 14 to point 11 results in the sudden reversal of the curvature. In point 11, bimetallic resumed its first stable position. With each passage from one stable position to another, the curvature decreases and then increases. The decrease in the curvature of the arc formed by the bimetal naturally causes an elongation of the rope, and an outgoing longitudinal force is thus generated at the ends of the bimetal during each breakdown.
    There are also devices for converting mechanical energy into electrical energy, for example implementing the properties of piezoelectric materials. A piezoelectric material is a material which, when subjected to mechanical deformation, generates an electrical voltage.
    There exist in the state of the art systems for converting thermal energy into electrical energy combining a bimetallic strip and a piezoelectric element. The bimetallic strip is generally placed between a heat source and a cold source, alternating cyclically from one bending to the other, and the piezoelectric element is generally stressed in torsion, being in particular designated in the art by "piezoelectric type 3 -1 ".
    Such a system is described in particular in US Patent Application 2015/01 15769 A1, wherein the piezoelectric element is fixed cantilevered on the bimetal. The suspended piezoelectric element vibrates during changes in position of the bimetallic strip.
    Another system of the state of the art has a piezoelectric element arranged against one of the temperature sources. During a breakdown, part of the kinetic energy of the bimetal is transferred to the piezoelectric element by mechanical shock.
    Current embodiments have many disadvantages, including limited thermal and mechanical transfer efficiencies, an undesirable effect of temperature on the piezoelectric efficiency, a diffusion of thermal energy in the piezoelectric element, a low working frequency, losses of mechanical energy in the support, or structural problems of positioning and encapsulation of the elements of the system.
    According to one embodiment, there is provided a system for converting thermal energy into electrical energy combining a bimetallic plate and a piezoelectric element having, in particular, better transfer and energy conversion efficiencies, an optimized operating procedure and simple manufacturing. .
    According to one aspect there is provided a system for converting thermal energy into electrical energy, comprising a chassis, at least one temperature-sensitive element held in the chassis by two of its ends between a hot source and a cold source, at least a piezoelectric element disposed between at least a portion of the frame and at least a first one of said two ends of said at least one temperature sensitive element, said at least one temperature sensitive element being configured to cyclically deform between two states under the action of the thermal gradient between the hot source and the cold source while exerting a stress during its cyclic deformation on said at least one piezoelectric element via said at least a first end.
    Thus, this configuration makes it possible to reduce the number of intermediate elements during the conversion of thermal energy into mechanical energy and during the conversion of mechanical energy into electrical energy. This results in a better overall efficiency of the system.
    Indeed, in contrast to the examples of the state of the art presented above, in this configuration there is no element diffusing heat between the temperature sources and the temperature-sensitive element. Similarly, the piezoelectric element being in direct connection with one end of the temperature sensitive element, the mechanical stress is directly applied to the piezoelectric element during each breakdown.
    Said stress on the piezoelectric element may be a constraint in compression.
    Indeed, the breakdown of a bimetal generates a longitudinal mechanical stress at its ends, causing, in this configuration, a compression of the piezoelectric elements.
    According to one embodiment, the temperature-sensitive element is, in at least one of its forms, in contact with one or the other of the hot or cold sources, or is very close to it.
    This optimizes the heat exchange between the temperature-sensitive element and at least one of the heat sources.
    Thus, the temperature of the temperature sensitive element rapidly reaches the breakdown temperatures, and the repetition frequency of the deformation cycle is optimized.
    According to one embodiment, the temperature-sensitive element comprises a bimetallic or bimetallic blade.
    The high expansion membrane of the bimetallic strip may comprise an iron-nickel-chromium alloy, for example 75% Fe-22% Ni-Cr 3% stoichiometry, known under the name NC4. The low expansion membrane of the bimetallic strip may comprise an iron-nickel alloy, for example 64% Fe-Ni 36% stoichiometry, known under the name of invar.
    A bimetal formed by the pair of materials NC4-Invar has advantageous properties in terms of efficiency of conversion of thermal energy into electrical energy due to a high thermomechanical coupling coefficient, in terms of mechanical power delivered, as well as ease of shaping and sizing of the bistability characteristics (breakdown temperature, amplitude, etc.). The temperature sensitive element can be punched at its center.
    Indeed, a punch or a mark, forming for example a circular edge on the surface of the bimetallic plate, gives an initial curvature bimetal and in particular improves the breakdown effect, and thus optimize the cycle of hysteresis of the bimetallic blade according to needs (breakdown temperature, amplitude ...).
    According to one embodiment, at least one fastening element is disposed between said at least one end of the temperature sensitive element and the piezoelectric element, and is configured to hold the temperature sensitive element by said less a first end.
    Such a fixing element makes it possible, in addition to keeping the temperature-sensitive element in good position, to avoid direct contact between the piezoelectric element and the temperature-sensitive element, protecting the piezoelectric element, for example from mechanical wear or unwanted heat transfer.
    In addition, such a fastener makes it possible to apply the stress in a homogeneous manner to an advantageous surface of the piezoelectric element. The fixing element may preferably be of a shape ensuring both a good retention of the temperature sensitive element, and imposing a minimum of mechanical stresses during shape changes.
    According to one embodiment, the piezoelectric element comprises a stack of layers of a piezoelectric material, for example PZT, forming a stack of piezoelectric capacitors in parallel, and is generally designated by the person skilled in the art under the term " piezoelectric stack 3-3 ".
    When a piezoelectric stack 3-3 is constrained in compression, an electric field is generated in the direction of the stress and the capacitive values of the stacked layers decrease. This results in significant electromechanical coupling in this direction and results in an efficient conversion of mechanical energy into electrical energy. For example, the piezoelectric stacks 3-3 have an electromechanical coupling factor greater than the piezoelectric 3-1, about 0.75 against respectively about 0.39, which is equivalent to 57% of the mechanical energy transformed into electrical energy against 15%.
    According to one embodiment, the piezoelectric element is isolated from the heat transfer between said hot source and said cold source.
    Thermal insulation makes it possible to overcome undesirable effects due to the temperature on the piezoelectric element, and thus the other thermal transfers can be optimized without negative effects on the energy collection.
    For example, said frame may be thermally insulating, to isolate the piezoelectric element from the heat transfer and also to maintain a high thermal gradient within the system.
    In another aspect, there is provided an energy recovery device, comprising an energy conversion system as defined above, and energy storage means coupled to the piezoelectric element and configured to store the energy. energy produced by the piezoelectric element.
    Such a device can in particular be used as a source of energy of autonomous systems with very low energy consumption. Other advantages and characteristics of the invention will appear on examining the detailed description of embodiments, in no way limiting, and the appended drawings in which: FIG. 1 previously described illustrates a hysteresis cycle of the position of a bimetallic strip as a function of temperature, and, - Figures 2 to 6 schematically illustrate different embodiments of an energy conversion system according to the invention. FIG. 7 schematically illustrates an energy recovery device supplying a load.
    Figures 2, 3 and 4 respectively show a perspective view and side views of an embodiment of a SYS system according to the invention, the elements common to said figures having the same references.
    In this embodiment, a hot source TC and a cold source TF are assembled facing one another by a thermally insulating frame 1, forming a free space 2 between them.
    A bimetallic or bimetallic strip 3, of rectangular shape and curved in its length, is placed in the free space 2. The bimetallic blade 3 comprises a high expansion membrane MKsup of thermal expansion coefficient Ksup and a low expansion membrane MKinf of coefficient of thermal expansion Kinf contiguous face to face.
    The bimetallic blade 3 is held in abutment on the edges 31, 32 of its longitudinal ends by two fixing elements 4, supported and / or fixed on piezocomposite stacks of type 3-3, themselves supported and / or fixed against the face of frame 1 facing towards space 2.
    The fastening elements 4 are thermally insulating and here comprise a triangular section groove in which the edges 31, 32 of the blade 3 are embedded, the blade 3 is then properly maintained while remaining free to turn.
    The face opposite to the groove of the fastening elements 4 is flat and its surface corresponds to an advantageously active surface of the piezocomposite stacks 5.
    In FIGS. 2 and 3, the bimetallic plate 3 is represented in a first stable position, in contact with the hot source TC, and corresponds to a position between the points 11 and 12 of the hysteresis cycle H represented in FIG.
    In FIG. 4, the blade 3 is in its second stable position, in contact with the cold source TF, and corresponds to a position between the points 13 and 14 of the hysteresis cycle H represented in FIG. 1. By way of example the temperatures of the hot sources TC and cold TF can be in a wide range from -40 ° C to 300 ° C. The breakdown temperatures Tel and Tc2 can have any value in this range, with Tc1> Tc2, and are fixed by the choice of the materials of the bimetallic strip, the dimensions of the bimetallic strip, and the initial curvature given to the bimetallic strip.
    For a given bimetal with breakdown temperatures Tel and Tc2 the operating condition is that the temperature of the cold source TF is lower than the breakdown temperature Tc2 and the hot source temperature TC is greater than the breakdown temperature Tel D ' on the other hand, the hot sources TC and cold TF have been represented in the form of regular parallelepipeds, but any shape, for example concave or convex surfaces, can be envisaged. Likewise, the groove of the fastening elements 4 can be of another form, for example of curved section.
    FIG. 5 represents an embodiment of the bimetallic blade 3 comprising a punch P in its middle. This punch P creates a circular fold C on the surface of the bimetallic plate 3 whose geometry makes it possible in particular to control the breakdown temperatures and the hysteresis cycle.
    The bimetallic plate 3 may be of macroscopic dimensions, of the order of cm 2, and the membranes may comprise in this case an iron-nickel alloy of different stoichiometries, such as, for example, Invar (Fe 64% -Ni 36%). These alloys can also contain chromium and / or manganese, increasing their coefficients of thermal expansion, such as for example NC4 (Fe 75% - Ni 22% - Cr 3%), or alloys (Mn 72% - Cu 18 % - Ni 10%), (Fe 74% - Ni 20% - Mn 6%). Other metals may be used, such as aluminum or copper.
    The blade 3 has a thickness of the order of a few tenths of a millimeter, in order to minimize its volume so as to accelerate the heating and the cooling of its mass, and thus to increase the repetition frequency of the deformation cycle.
    The bimetallic blade can also be of micrometric dimensions, and the membranes can be made in thin film technology, combining materials such as Si-Al, SiO 2 -Al, Si-Au, SiCh-Au, SiPb for example, on thicknesses of a few tens of micrometers.
    That being so, the temperature sensitive element can also be formed of shape memory alloy having stored two shapes. The shape memory alloys may be for example Cu-Zn, Cu-Zn-Al, Cu-Ni-Al, Au-Cd, Fe-Pt.
    In all cases, the stoichiometry of the materials is chosen according to the temperature range of use fixed by the hot and cold sources.
    FIG. 6 represents a sectional view of a piezoelectric stack 3-3, comprising a stack of layers 61 of a piezoelectric material. The piezoelectric material may be for example PZT, or a piezocomposite comprising a piezoelectric material and a non-piezoelectric material.
    Each layer 61 is connected to the neighboring layers by electrodes 62, forming as many piezoelectric capacitors.
    The electrodes 62 are alternately connected to nodes 63 and 64 thus constituting the terminals of the piezoelectric capacitance equivalent to the piezoelectric capacitances of each layer in parallel.
    The ends of the stack are usually protected by ceramic interfaces 66, and the stack is encapsulated radially by an insulating coating 68.
    DC arrows represent a compressive stress applied to the piezoelectric stack 3-3.
    When the DC stress is large enough to introduce a deformation of the piezoelectric stack 3-3, an electric voltage is generated between each electrode, and the electrodes of each piezoelectric capacitance approach each other, decreasing the value of said equivalent capacitance.
    Fig. 7 shows an energy recovery DIS device used as a power source for powering a BAT load.
    The DIS device comprises a SYS system as described above, whose hot source TC is in contact or close to a heat generator GCH and whose cold source TF is in contact or close to a heat sink DCH.
    The heat generator GCH may for example be a hot element of an electronic circuit in operation, such as a microcontroller, or any other hot source.
    The heat sink may be for example a radiator or any other cold source.
    The thermal gradient between the hot sources TC and cold TF, temperatures respectively imposed by the heat generator GCH and the heat sink DCH, allows the system SYS to generate electrical energy.
    The piezoelectric elements of the SYS system are connected to a BAT energy storage means, for example a capacitor, capable of storing the electrical energy, via an MGE energy management means configured to optimize the charging of the BAT means to from the voltage signals produced by the piezoelectric elements 3 of the SYS system.
    权利要求:
    Claims (9)
    [1" id="c-fr-0001]
    1. System for converting thermal energy into electrical energy (SYS), comprising a frame (1), at least one temperature-sensitive element (3) held in the frame (1) by two of its ends (31, 32). ) between a heat source (TC) and a cold source (TF), at least one piezoelectric element (5) disposed between at least a portion of the frame (1) and at least one of said two ends (31, 32) of said at least one temperature-sensitive element (3), said at least one temperature-sensitive element (3) being configured to cyclically deform between two states under the action of the thermal gradient between the hot source (TC) and the cold source (TF) while exerting a stress during its cyclic deformation on said at least one piezoelectric element (5) via said at least one end.
    [2" id="c-fr-0002]
    2. Energy conversion system according to claim 1, wherein the temperature sensitive element (3) is, in at least one of its forms, in contact with one or other of the hot sources (TC ) or cold (TF).
    [3" id="c-fr-0003]
    An energy conversion system according to claims 1 or 2, wherein the temperature sensitive element (3) comprises a bimetallic blade.
    [4" id="c-fr-0004]
    An energy conversion system according to any one of the preceding claims, wherein the temperature sensitive element (3) is punched at its center.
    [5" id="c-fr-0005]
    An energy conversion system according to any one of the preceding claims, further comprising at least one fastener (4) disposed between said at least one end of the temperature sensitive element (3) and the piezoelectric element (5), and configured to maintain the temperature sensitive element (3) by said at least one end.
    [6" id="c-fr-0006]
    An energy conversion system according to any one of the preceding claims, wherein the piezoelectric element (5) comprises a stack of piezoelectric capacitors in parallel.
    [7" id="c-fr-0007]
    An energy conversion system according to any one of the preceding claims, wherein said stress on the piezoelectric element (5) is a compressive stress.
    [8" id="c-fr-0008]
    An energy conversion system according to any one of the preceding claims, wherein the piezoelectric element (5) is isolated from the heat transfer between said hot source (TC) and said cold source (TF).
    [9" id="c-fr-0009]
    An energy recovery device, comprising an energy conversion system (SYS) according to any one of the preceding claims, energy storage means (BAT) coupled to the piezoelectric element (5) and configured for storing the energy produced by the piezoelectric element (5).
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2007087383A2|2006-01-25|2007-08-02|The Regents Of The University Of California|Energy harvesting by means of thermo-mechanical device utilizing bistable ferromagnets|
    US20080100181A1|2006-10-20|2008-05-01|Clingman Dan J|Non-linear piezoelectric mechanical-to-electrical generator system and method|
    EP2309560A1|2009-10-12|2011-04-13|STMicroelectronics SAS|Thermoelectric Generator|
    EP2312154A1|2009-10-12|2011-04-20|STMicroelectronics SAS|Thermoelectric generator|
    WO2013007693A1|2011-07-11|2013-01-17|Commissariat à l'énergie atomique et aux énergies alternatives|System for converting thermal energy into electrical energy|
    US20130257219A1|2012-04-02|2013-10-03|Stmicroelectronics Sas|Energy harvesting device|
    US20150300328A1|2014-04-17|2015-10-22|Stmicroelectronics Sas|Thermoelectric generator comprising a deformable by-layer membrane exhibiting magnetic properties|
    CN107044321B|2017-05-26|2019-06-04|北京汽车研究总院有限公司|A kind of automotive exhaust heat recyclable device and the vehicle with it|
    US10818088B2|2018-07-10|2020-10-27|Curious Company, LLC|Virtual barrier objects|
    US10902678B2|2018-09-06|2021-01-26|Curious Company, LLC|Display of hidden information|
    US11055913B2|2018-12-04|2021-07-06|Curious Company, LLC|Directional instructions in an hybrid reality system|
    US10970935B2|2018-12-21|2021-04-06|Curious Company, LLC|Body pose message system|
    US10872584B2|2019-03-14|2020-12-22|Curious Company, LLC|Providing positional information using beacon devices|
    GB2594817A|2019-08-01|2021-11-10|Katrick Tech Limited|Energy harvesting system and method of manufacture|
    法律状态:
    2016-09-21| PLFP| Fee payment|Year of fee payment: 2 |
    2017-04-28| PLSC| Publication of the preliminary search report|Effective date: 20170428 |
    2017-09-21| PLFP| Fee payment|Year of fee payment: 3 |
    2018-09-19| PLFP| Fee payment|Year of fee payment: 4 |
    2019-09-19| PLFP| Fee payment|Year of fee payment: 5 |
    2021-07-09| ST| Notification of lapse|Effective date: 20210605 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1560185A|FR3042925B1|2015-10-26|2015-10-26|SYSTEM FOR CONVERTING THERMAL ENERGY INTO ELECTRICAL ENERGY.|FR1560185A| FR3042925B1|2015-10-26|2015-10-26|SYSTEM FOR CONVERTING THERMAL ENERGY INTO ELECTRICAL ENERGY.|
    US15/139,151| US10075102B2|2015-10-26|2016-04-26|System for converting thermal energy into electrical power|
    EP16194966.4A| EP3163739B1|2015-10-26|2016-10-21|Thermal to electrical energy converter system|
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