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    • 专利摘要:
    separator with increased puncture resistance. the present invention relates to a separator with a non-woven basic body, in which the basic body is provided with a coating, in which the coating contains particles of filler material and cellulose, in which the coating contains flexible organic particles of binder and in which the filler particles and the flexible organic binder particles are linked with each other through cellulose, with respect to the objective, it is to configure and develop a separator in such a way that it, with an increased mechanical stability , shows a high permeability, characterized by the fact that cellulose contains cellulose derivatives, which have a chain length of at least 100 repeat units, preferably a chain length of at least 200 repeat units.
    公开号:BR112012033046B1
    申请号:R112012033046-2
    申请日:2010-08-11
    公开日:2020-09-24
    发明作者:Michael Roth；Christoph Weber；Margitta Berg；Sigrid Geiger；Klaus Hirn；Christian Waschinski；Sandra Villing-Falusi；Maxim Kasai
    申请人:Carl Freudenberg Kg；
    IPC主号:
    专利说明:

    [0001] [0001] The present invention relates to a separator. TECHNICAL STATUS
    [0002] [0002] Separators of the mentioned type are already known from WO 2009/033627 A1. These separators are coated with particles of filler material and can be used in Li ion cells or condensers.
    [0003] [0003] A failure of Li ion cells can have external or internal causes. External causes include an incorrect battery handling system or incorrect temperature control. Internal failures can be induced by cellular chemistry, degradation processes or internal short circuits.
    [0004] [0004] External causes can be influenced only conditionally by configuring the cell. The internal causes, however, should be reduced or eliminated, to allow for the prolonged use of highly capable Li ion cells.
    [0005] [0005] About 90% of all cell failures in Li ion batteries are induced by internal short circuits. An internal short circuit occurs when one or more electrode grains in the operation of a battery are pushed through the separator and form an electrically conductive route, which leads to a short circuit.
    [0006] [0006] Through spontaneous discharge of the cell in a short circuit, a very strong local heat generation occurs, which allows many separators to shrink or fuse. In the best case, it leads to "only" a failure, in the worst case, to an explosion or inflammation of the cell. The larger the cells, the more problematic the processes mentioned above, since the energy accumulated in the cell correlates with its capacity.
    [0007] [0007] Common porous separators based on polyolefin membranes, but also ceramic separators, have good electrical properties, which have stood out in the last 15 years for the increased energy density or the power density of Li ion cells.
    [0008] [0008] The disadvantage of these separators, however, are their thermal and mechanical properties. Thus, for example, polypropylene and polyethylene show a low melting point and porous membranes of these materials show high shrinkage and, consequently, limited mechanical stability.
    [0009] [0009] Other weaknesses are especially low resistance to puncture and resistance to breakage of polyolefin membranes, as well as ceramic separators. These weaknesses always lead to partly dramatic cell failures.
    [0010] [00010] Unfortunately, the mechanical properties of the separators, in addition to the safety of electrochemical cells, also influence their electrical properties. As soon as the mechanical properties of a separator are improved to, for example, increase its puncture resistance, a denser separator with the same structure should be used. With this, however, reduced porosity and, thus, greater electrical resistance in the cell, since the electrolyte may diffuse worse through the membrane. PRESENTATION OF THE INVENTION
    [0011] [00011] Therefore, the objective of the invention is based on designing and developing a separator of the type mentioned above, which shows a high permeability with an increased mechanical stability.
    [0012] [00012] The objective mentioned above is solved through the characteristics of the invention.
    [0013] [00013] The cellulose derivatives used have, according to the invention, a chain length of at least 100 repetition units (DP = 100), preferably a chain length of at least 200 repetition units. This surprisingly leads to much better mechanical properties. Due to the use of selected modified cellulose derivatives, surprisingly the homogeneity and stability of the coating solution and, thus, also the separator coating can be decisively improved.
    [0014] [00014] According to the invention, the safety in the operation of Li ion cells is markedly increased by such a separator. Surprisingly, it has been found that a nonwoven coated with cellulose derivatives, where the coating has hard inorganic or organic particles of filler material and flexible organic binder particles, has particularly good mechanical properties. The use of cellulose derivatives, surprisingly, also leads to a homogeneous coating. In addition, surprisingly, a very high resistance to puncture and a very high resistance to the propagation of rupture are adjusted, which until now are not known of similar separators in the prior art. The danger of an internal short circuit is greatly reduced by the best mechanical properties, in which the permeability of the separator is not negatively influenced. This is expressed in a very low Gurley index, which is a very accessible quantity to be measured and disseminated in the scientific world, to determine the permeability or tortuosity of porous membranes. A low Gurley index confirms that transport of microscopic material through the separator is carried out without problems. Material transport correlates with resistance in the battery cell. As long as a separator is specified, it shows high permeability with increased mechanical stability.
    [0015] [00015] Therefore, the objective initially mentioned is resolved.
    [0016] [00016] Cellulose derivatives can be endowed with cellulose ethers and / or cellulose esters. Cellulose derivatives cellulose ethers and cellulose esters lead to particularly stable separators. Cellulose derivatives have a degree of substitution of 0.7, preferably 0.9, to form an ideal hydrophilic mass within the coating solution. In this way, on the one hand, surprisingly good film-forming properties of the coating solution are obtained, on the other hand, it prevents decisively agglomeration of the particles of filler material. Hereby, an almost perfect homogeneous coating is obtained.
    [0017] [00017] Through the use of special surfactants, that is, nonionic surfactants, surprisingly, the homogeneity and stability of the coating solutions and, thus, also the separator coating can be decisively improved. This leads, surprisingly, to much improved mechanical properties. Through the use of small proportions of non-ionic surfactants of less than 5%, preferably less than 2%, particularly preferably less than 1% in the solid content of the coating, the homogeneity and uniformity of the mixture can be surprisingly very improved.
    [0018] [00018] The coating could contain nonionic surfactants, which contain the alkylated octyl and / or nonylphenol ethoxylates and / or ethylene oxide / propylene oxide glass-polymer. These surfactants are particularly well suited to positively influence the homogeneity of the coating solution. Ionic surfactants, on the contrary, can cause agglomerations of the particles of filler material and thus lead to de-mixing and / or coagulation of the particles of filler material loaded into the coating solution.
    [0019] [00019] The flexible organic binder particles can make up a proportion of at least 2% by weight, preferably at least 5% by weight, particularly preferably at least 10% by weight, of the coating. By this means, very high resistance to perforation and resistance to the propagation of the break of the separator are already obtained and, at the same time, surprisingly high air permeability. With a proportion of at least 11%, particularly high resistance to puncture of the separator results.
    [0020] [00020] The binder particles could be less than 1 μm (d50) in size, preferably less than 0.5 μm (d50) and particularly preferably less than 0.3 μm (d50). d50 designates the average particle size or diameter.
    [0021] [00021] The particles of filler material could have a maximum size of 5 μm (d50), preferably 2 μm (d50), particularly preferably, they could be smaller than 1 μm (d50). These particle sizes of filler material have been proven to be suitable for coating a nonwoven well. The choice of the average diameter of this strip proves to be particularly advantageous, in order to avoid short circuits due to the formation of dendritic streaks or friction.
    [0022] [00022] The particles of filler material could be distributed homogeneously in the basic body. Through this specific configuration, short circuits can be avoided particularly effectively. Metal dendrites and friction can hardly move across a homogeneous coated surface. In this context, it is concretely conceivable that all the pores of the nonwovens are homogeneously filled with the particles of filler material in such a way that the separator shows predominantly pore sizes, which are smaller than the average diameters of the particles of filler material. .
    [0023] [00023] The particles of filler material could be linked together with the nonwoven by means of binder particles. In that case, the binder particles could consist of organic polymers. The use of organic polymer binder particles allows to produce a separator with satisfactory mechanical flexibility. Styrene-butadiene shows surprisingly excellent binding properties.
    [0024] [00024] In preferred embodiments, the binder particles could contain polyester, polyamide, polyether, polycarboxylates, a polycarboxylic acid, a polyvinyl compound, a polyolefin, a rubber, a halogenated polymer and / or an unsaturated polymer.
    [0025] [00025] The binder particles can be used in the form of homopolymers or as copolymers. Suitable copolymers, for example, are statistical copolymers, gradient copolymers, alternate copolymers, block copolymers or graft polymers. Copolymers can consist of two, three, four or more different monomers (terpolymers, tetrapolymers).
    [0026] [00026] Preferably, thermoplastic, elastomeric and / or duraplastic binder particles could be used. In this context, mention is made, for example, of polyvinylpyrrolidone, polyacrylic acid, polyacrylates, polymethacrylic acid, polymethacrylates, polystyrene, polyvinyl alcohol, polyvinyl acetate, polyacrylamide, polyvinylide-fluoride and copolymers of cellulose and its derivatives, and the above. polyurethanes, nitrile rubber (NBR), styrene-butadiene rubber (SBR), as well as latex.
    [0027] [00027] In a preferred embodiment, the polymer, from which the binder particles are produced, could be an unsaturated polymer. In that case, unsaturated groups can be, for example, carbon-carbon double bonds or triple bonds or carbon-nitrogen double bonds or triple bonds. C = C double bonds are preferred. These can be uniformly distributed in the polymer, such as, for example, in the case of polymers that can be obtained by polymerizing dienes. Such polymers can also be partially hydrogenated. Alternatively, the basic polymer structures can be coupled with radicals, which contain unsaturated groups. Unsaturated polymers generally stand out for their good adhesive properties.
    [0028] [00028] In a preferred embodiment, the polymer, from which the binder particles are produced, could be a polyvinyl ether. Suitable monomeric composition elements are, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, octyl, decyl, dodecyl, 2-ethylhexyl, cyclohexyl, benzyl, trifluoromethyl, hexafluorpropyl or tetrafluorpropylvinyl. In this case, for example, homopolymers or copolymers, especially block copolymers, can be used. Copolymers can consist of several monomeric vinyl ethers or be copolymers of vinyl ether monomers with other monomers. Polyvinyl ethers are particularly suitable as binders, as they have very good adhesive and adhesion properties.
    [0029] [00029] In a preferred embodiment, the polymer, from which the binder particles are produced, could be a halogenated polymer. This can be prepared, for example, from vinylidene fluoride (VDF), hexafluorpropylene (HFP) or chlorotrifluorethylene (CTFE) or contain such monomeric composition elements. In this case, for example, homopolymers or copolymers, especially block copolymers, can be used. Copolymers can consist of several halogenated monomers or be copolymers of halogenated monomers with other monomers. Polymers and monomers can be completely fluorinated or chlorinated or partially fluorinated or chlorinated. In a preferred embodiment of the invention, the proportion of the comonomer of the halogenated monomers, especially of HFP and CTFE, in the total polymer, matters between 1 and 25% by weight. Halogenated polymers generally stand out for their high temperature resistance and resistance to chemicals, as well as for good humectability. They are particularly suitable as binders, when fluorinated or partially fluorinated particles are used for filling the nonwoven. Through the use of copolymers, temperature resistance and processing temperature can vary over a wide temperature range. With this, the processing temperature of the binder can be adapted to the melting temperature of the particles.
    [0030] [00030] In another embodiment, the polymer, from which binder particles are produced, could be a polyvinyl compound. Especially suitable are those, which consist of N-vinylamide monomers, such as N-vinylformamide and N-vinylacetamide or contain such monomers. Especially suitable are the corresponding homopolymers and copolymers, such as block copolymers. Poly-N-vinyl compounds stand out for their good wettability.
    [0031] [00031] In a preferred embodiment, the polymer, from which the binder particles are produced, could be a rubber. Generally known rubbers can be used, such as ethylene-propylene-diene rubber (EPDM rubber). EPDM rubber in particular has a high elasticity and good chemical resistance, especially in relation to polar organic media and this can be used over a wide temperature range. Rubbers can also be used, selected from natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene-butadiene rubber or nitrile-butadiene rubber. These rubbers contain double unsaturated bonds. They stand out for their good adhesion effect. In that case, homopolymers or copolymers, especially block copolymers, can be used.
    [0032] [00032] Fluorinated rubbers, such as perfluor rubber (FFKM), fluorine rubber (FKM) or propylene-tetrafluorethylene rubber (FPM), as well as copolymers thereof, can also be used. FFKM is particularly preferred. These polymers, especially FFKM, stand out for their high temperature usage range, very good resistance to media and chemicals and low swelling. Therefore, they are especially suitable for applications in aggressive medium at high temperatures, such as in fuel cells.
    [0033] [00033] In a preferred embodiment, the polymer, from which the binder particles are produced, could be a polyester or a polyamide or a copolymer thereof. Copolymers can consist of several polyamide and / or polyester monomers or be copolymers of those monomers with other monomers. Such binder particles are characterized by very good adhesion properties.
    [0034] [00034] The binder particles could also contain polymers containing silicon and / or silicon-organic. In one embodiment, siloxas are used as binders. In another embodiment, silyl compounds and / or silanes are used as binder particles. Such binder particles, especially silyl and / or silane compounds, are preferably used, when the filler particles are completely or at least in part organic particles.
    [0035] [00035] The melting point of the binder particles and / or the particles of filler material could be below the melting points of the nonwoven fibers. By choosing these binder particles or filler material, the separator can thus carry out a so-called "shut-down mechanism". In a "shut-down mechanism", the particles to be fused close the pores of the nonwoven, so that dendritic streak through the pores and thus short circuits cannot occur.
    [0036] [00036] In this context, it is conceivable that mixtures of particles of filler material and / or binder particles are used with different melting points. By this means, a gradual or staggered closing of the pores can be carried out with increased temperature.
    [0037] [00037] The particles of filler material may consist of organic polymers. Suitable polymers are, for example, polyacetals, polycyclic olefin copolymers, polyesters, polyimides, polyether ketones, polycarboxylates and halogenated polymers.
    [0038] [00038] Organic polymers can be homopolymers or copolymers. Suitable copolymers are, for example, statistical copolymers, gradient copolymers, alternating copolymers, block copolymers or graft polymers. Copolymers can consist of two, three or more different monomers (terpolymers, tetrapolymers). The materials mentioned can also be processed into particles in the form of mixtures. However, thermoplastic polymers and polymeric mixtures or crosslinked polymers and polymeric mixtures, such as elastomers or duraplants, can be used.
    [0039] [00039] The filler particles could be prepared from polypropylene, polyethylene, polyvinylpyrrolidone, polyvinylidene fluoride, polyester, polytetrafluoroethylene (PTFE), perfluorethylene-propylene (FEP), polystyrene, polyacrylates, as well as copolymers of the polymers mentioned above. . Particularly preferred are homopolymers, copolymers or block copolymers of vinyl fluoride (VDF), polytetrafluoroethylene (PTFE) and polyoxymethylene (POM, also mentioned polyacetal or polyformaldehyde).
    [0040] [00040] In a preferred embodiment of the invention, the filler particles consist of polyacetals, such as polyoxymethylene (POM) or the filler particles contain polyacetals. Copolymers of acetals can also be used, for example, with trioxane as a comonomer. Polyacetals stand out for their excellent dimensional resistance and at room temperature. In addition, they have only a small water absorption. According to the invention, this is advantageous, since the filled non-woven fabric absorbs all in all, therefore, only little water.
    [0041] [00041] In another embodiment of the invention, the particles of filler material could consist of cycloolefin copolymers (COC) or contain them. The thermal properties of COC can be specifically altered by changing the proportions of incorporation of cyclic and linear olefins in another area and, with this, be adjusted to the desired application areas. Substantially, with this, the dimensional stability under heat can be adjusted in a range of 65 to 175oC. COCs stand out for their extremely low water absorption and very good electrical insulation properties.
    [0042] [00042] In another embodiment of the invention, particles of filler material could consist of polyesters or contain them. Preference is given especially to liquid crystalline polyesters (LCP). These are offered, for example, by the trade name "Vectra LCP" of the company Ticona. Liquid crystalline polyesters stand out for their high dimension stability, high temperature resistance and good resistance to chemicals.
    [0043] [00043] In another embodiment of the invention, the particles of filler material could consist of polymers (PI) or copolymers thereof or contain them. Suitable copolymers are for example polyetherimides (PEI) and polyamidimides (PAI). The use of polimides is advantageous, since they have a high mechanical hardness and a high temperature resistance. In addition, they demonstrate good surface characteristics, which can be precisely adjusted from hydrophilic to hydrophobic.
    [0044] [00044] In another embodiment of the invention, the particles of filler material could consist of a fluorinated or halogenated polymer or contain it. This can be produced, for example, from vinylidene fluoride (VDF), polytetrafluoroethylene (PTFE), hexaflu-orpropylene (HFP) or chlorotrifluorethylene (CTFE). In this case, for example, homopolymers or copolymers, especially block copolymers, can be used. Copolymers can consist of several halogenated monomers or be copolymers of halogenated monomers with other monomers. Polymers and monomers can be completely fluorinated or chlorinated or partially fluorinated or chlorinated. In a particular embodiment of the invention, the proportion of the comonomer of the halogenated monomers, especially of HFP and CTFE, of the total polymer matters between 1 to 25% by weight. Halogenated polymers are characterized by high temperature resistance and resistance to chemicals, as well as good humectability. These are particularly suitable for use with fluorinated or partially fluorinated binder particles. Through the use and choice of copolymers, temperature resistance and processing temperature can vary over a wide temperature range. With this, the processing temperature of the binder particles can be adjusted to the melting temperature of the filler particles. In addition, it is possible to adjust a shut-down temperature.
    [0045] [00044] In another embodiment of the invention, the particles of filler material could consist of a fluorinated or halogenated polymer or contain it. This can be produced, for example, from vinylidene fluoride (VDF), polytetrafluoroethylene (PTFE), hexaflu-orpropylene (HFP) or chlorotrifluorethylene (CTFE). In this case, for example, homopolymers or copolymers, especially block copolymers, can be used. Copolymers can consist of several halogenated monomers or be copolymers of halogenated monomers with other monomers. Polymers and monomers can be completely fluorinated or chlorinated or partially fluorinated or chlorinated. In a particular embodiment of the invention, the proportion of the comonomer of the halogenated monomers, especially of HFP and CTFE, of the total polymer matters between 1 to 25% by weight. Halogenated polymers are characterized by high temperature resistance and resistance to chemicals, as well as good humectability. These are particularly suitable for use with fluorinated or partially fluorinated binder particles. Through the use and choice of copolymers, temperature resistance and processing temperature can vary over a wide temperature range. With this, the processing temperature of the binder particles can be adjusted to the melting temperature of the filler particles. In addition, it is possible to adjust a shut-down temperature of the company Dupont. According to the invention, this is advantageous because it has good cationic and protonic conductivity.
    [0046] [00046] The use of organic polymers for the particles of filler material allows a smooth fusion of the particles to obtain a "shut-down effect". In addition, a separator can be produced, which can be cut without problems, without crumbling. Crumbing of the separator occurs most of the time, when a relatively large portion of inorganic particles of filler material is present. In this context, it is conceivable to use mixtures of different particles of filler material or core-shell particles. Hereby, a gradual or staggered closing of the pores in the separator can be caused by increasing the temperature.
    [0047] [00047] Usable binder particles and filler particles, especially organic filler particles, are preferably temperature resistant to a high degree. Preferably, the binder particles and / or the particles of filler material are resistant to temperatures of 100, 150, 175 or 200 ° C. This allows for use in fuel cells.
    [0048] [00048] It is also conceivable to use inorganic particles of filler material or inorganic-organic hybrid particles. These particles of filler material do not melt at a temperature below 400 ° C. In addition, these particles of filler material can be selected with basic properties, to at least partially reduce the protonic activity present in batteries.
    [0049] [00049] As inorganic particles of filler material, for example, metal oxides, metal hydroxides and silica are suitable. These may consist of aluminum oxides, silicon oxides, zeolites, titanates and / or perowskites or contain them. Mixtures of these particles of filler material or mixtures with other materials can also be used.
    [0050] [00050] In an embodiment of the invention, inorganic filler particles can be used mixed with organic filler particles. Inorganic particles of filler material may intrinsically have a cracked or porous structure and in this way increase porosity, especially of mixtures of particles of filler material. They also have high temperature stability, high chemical stability and good wettability. Thus, for example, mixtures of organic and inorganic particles of filler material can be used, in which up to 2, 5, 10, 25 or 50% by weight of the filler particles are inorganic filler particles.
    [0051] [00051] It is also possible to use inorganic particles of filler material, which are spherical or whose external shape has a uniform arrangement of areas, which approach a sphere. Such particles of filler material can be obtained, for example, by crystallization.
    [0052] [00052] The nonwoven described here, unlike known nonwovens, can also be produced without inorganic particles of filler. In one embodiment of the invention, no inorganic particles of filler material or particles of filler material with inorganic components are contained.
    [0053] [00053] Usable filler particles can be prepared by known methods. Thus, processes are known in which particles of suitable filler material, especially spherical, can already be obtained as a polymerization reaction product. Preferred processes are emulsion or dispersion polymerization.
    [0054] [00054] In another embodiment, particles of filler material can be obtained by processing polymers. For example, polymer granules can be ground. Optionally below, separation processes, such as sieving, are used to obtain the desired size distribution. The particles of filler material may consist of mixtures of different particle sizes. As a result, porosity and pore size distribution may vary.
    [0055] [00055] Nonwoven fibers could be manufactured from organic polymers, especially polybutyl terephthalate, polyethylene terephthalate, polyacrylonitrile, polyvinylidene fluoride, polyethylene ketones, polyethylene terephthalate, polysulfones, polyimide, polyester, polypropylene, polyethylene, polyoxymethylene, polyamide or polyvinylpyrrole-dona. It is also conceivable to use biocomponent fibers, which have the polymers mentioned above. The use of these organic polymers allows to produce a separator, which shows only a small thermal shrinkage. In addition, these materials are largely electrochemically stable compared to the electrolytes and gases used in batteries and condensers.
    [0056] [00056] The average length of the nonwoven fibers could exceed their average diameter by at least twice, preferably four times. Through this concrete configuration, a particularly resistant non-woven fabric can be prepared, since the fibers can be interwoven with each other.
    [0057] [00057] At least 90% of the nonwoven fibers could have an average diameter of a maximum of 12 μm. This concrete configuration allows the construction of a separator with relatively small pore sizes. Even finer porosity can be achieved by the fact that at least 40% of the nonwoven fibers have an average diameter of at most 8 μm.
    [0058] [00058] The separator could be characterized by a maximum thickness of 100 μm. A separator of this thickness can still be rolled up without problems and allows a very safe operation of the battery. Preferably, the thickness could matter at most 60 μm. This thickness allows for a better winding capacity even more secure battery operation. Particularly preferably, the thickness could matter at most 35 μm. With separators of such thickness, compact batteries and capacitors can be built. Most preferably, the thickness could matter at most 25 μm. With separators of such thickness, batteries with a high energy density can be built.
    [0059] [00059] The separator could have a porosity of at least 25%. A separator of this porosity particularly effectively suppresses the formation of short circuits due to its density of the material. Preferably, the separator could have a porosity of at least 35%. Through a separator of this porosity, it is possible to manufacture a battery with high power density. The separator described here shows, with high porosity, however, very small pores, so that dendritic streaks cannot form from one side to the other side of the position. In this context it is conceivable that the pores form a labyrinth-like structure, in which no dendritic streak can form from one side to the other side of the separator. In another embodiment, the porosity is between 25 and 70, preferably between 35 and 60%, particularly preferably between 45 and 55%.
    [0060] [00060] The separator could have pore sizes of a maximum of 10 μm, preferably of a maximum of 3 μm. The choice of this pore size has proved to be particularly advantageous, to avoid short circuits. Particularly preferably, the pore sizes could matter at most 1 μm. Such a separator particularly avoids short-circuits caused by the growth of metallic dendrites, friction of electrode particles and direct contact of the electrodes when requesting pressure.
    [0061] [00061] The weight of the separator according to the invention could be between 10 and 60, especially between 15 and 50 g / m2.
    [0062] [00062] The separator could show a resistance to the propagation of the rupture in the transverse direction of at least 0.3 N, preferably of at least 0.5 N and a resistance to the propagation of the rupture in the longitudinal direction of at least 0.3 N, preferably 0.4 N. This separator is extremely stable and can be rolled up without problems. The higher resistance against the propagation of rupture also reduces the sensitivity of the material compared to the mechanical stress in the cut in the longitudinal and transverse direction. Furthermore, this improves the safety properties, when in bending tests, the impact behavior of a battery is tested in automotive applications.
    [0063] [00063] The separator could lose its insulating effect in a positioning between two conductive electrodes when requested with a force of at least 500 N, preferably of at least 600 N, particularly preferably of at least 700 N, where with this force, a stamp with a spherical head and a diameter of 6 mm is pressed on the composite of separator and electrodes. Such a separator has a high stability and resistance to perforation.
    [0064] [00064] The separator could be mechanically fixed using a calender. Calendering causes a reduction in surface roughness. The particles of filler material and / or the particles of the binder used on the nonwoven surface show flattening after calendering.
    [0065] [00065] The coating could present unevenness, which protrudes at most 1 μm from the level and / or the coating could present recesses, which present a depth of at most 1 μm. Research on a 30 μm thick separator has shown that the coating has unevenness, which stands out at a maximum of 1 μm from the level. In addition, the recesses in the cladding have a depth of at most 1 μm. The aging behavior of the battery is favorably influenced by such a separator.
    [0066] [00066] The flexible organic binder particles could have a softening point or glassy point less than 20 ° Celsius, particularly preferably less than 0 ° Celsius. Flexible organic particles of binder in the sense of this specification are understood to mean particles with a softening point or a lower glassy point equal to 20 ° Celsius. The combination of these flexible organic binder particles with hard particles of filler material leads to a highly ductile elastic behavior of the separator and causes a marked increase in resistance to deformation.
    [0067] [00067] The separator described here can be used especially in batteries and capacitors as a separator, since it prevents short circuits particularly effectively.
    [0068] [00068] This can also find use in fuel cells as a gas diffusion layer or membrane, since it shows good humidification properties and can transport fluids.
    [0069] [00069] By a separator in the sense of that specification it is understood a composite with the characteristics of the invention.
    [0070] [00070] There are, then, several possibilities to configure and develop the study of the present invention in an advantageous way. For this, on the one hand, reference should be made to the embodiments, on the other hand, to the subsequent elucidation of preferred embodiments of the invention based on the drawing.
    [0071] [00071] In combination with elucidating the preferred embodiments of the invention based on the drawing, the preferred embodiments and developments of the study are also generally elucidated. SUMMARY OF DRAWINGS
    [0072] [00072] The drawings show: figure 1 a measuring installation to determine the resistance of separators to perforation, figure 2 a diagram to compare the resistances of separators to perforation, figure 3 a diagram showing the resistances of separators to the propagation of the rupture, figure 4 a diagram showing the resistances of separators to the propagation of the rupture in cross section, figure 5 a diagram, which shows the Gurley indices for separators, Figure 6 is a schematic representation of a test sample to perform the break resistance test and figure 7 shows a scanning electron microscopy (REM) image of execution example 3, which confirms how uniform and high quality the coating or embedding is. Execution of the Invention Examples of execution: Example 1:
    [0073] [00073] To 251 parts of a 2.5% solution of carboxymethylcellulose, 221 parts of a 70% dispersion of aluminum oxide (Al2O3) (d50 = 0.7 μm) were added and stirred for 30 minutes. Then, 10 parts of an alkylphenol ethoxylate were added and then 24 parts of a dispersion at 48% colloidal NBR (pH = 9.6; TG = -12oC (glass temperature), also under stirring. it was stirred for 2 hours and tested for at least 24 hours for stability.The viscosity of the obtained solution was 290 cP The fraction of the flexible organic binder particles in the coating matters 6.3%. Coating:
    [0074] [00074] A non-woven PET 65 cm wide (thickness: 22 μm, weight: 1 g / m2) was continuously coated with the above solution by means of a roller coating process and dried without contact, at 125oC. A coated non-woven fabric with a weight of 49 g / m2 and a thickness of 40 μm was obtained. The average pore size of the coated non-woven imported 0.2 µm. Example 2:
    [0075] [00075] To 98010 parts of a 1.5% solution of carboxymethylcellulose, 46594 parts of a 66% dispersion of aluminum oxide (Al2O3, d50 = 2.5 μm) were added and stirred for 30 minutes. Then, 3000 parts of an alkylphenol ethoxylate were added and then 5396 parts of a flexible dispersion to 48% colloidal NBR (pH = 9.6; TG = -12oC), also under stirring. The solution was stirred for 3 hours and tested for at least 24 hours for stability. The viscosity of the obtained solution imported in 100 cP. The solid fraction of the flexible organic binder particles in the coating matters at 7.4%. Coating:
    [0076] [00076] A non-woven PET 58 cm wide (thickness: 19 μm, weight: 11 g / m2) was continuously coated with the above solution by means of a roller coating process and dried at a temperature of 125oC. A nonwoven impregnated with a weight of 35 g / m2 and a thickness of 36 μm was obtained. The average pore size of the coated non-woven imported 0.2 µm. Example 3:
    [0077] [00077] To 251 parts of a 2% solution of carboxymethylcellulose, 221 parts of a 65% dispersion of aluminum oxide (Al2O3, d50 = 2 μm) were added and stirred for 30 minutes. Then, 5 parts of an alkylphenol ethoxylate were added and then 40 parts of a dispersion of binder to 48% colloidal NBR, also under stirring. The solution was stirred for 3 hours and tested for at least 24 hours for stability. The viscosity of the solution obtained was 290 cP. The solid fraction of the flexible organic binder particles in the coating matters by 11.1%. Coating:
    [0078] [00078] A 58 cm wide PET non-woven (thickness: 20 μm, weight: 11 g / m2) was continuously coated with the above solution by means of a roller coating process and dried at a temperature of 120 ° Ç. A nonwoven impregnated with a weight of 31 g / m2 and a thickness of 34 μm was obtained. The average pore size of the coated non-woven imported 0.6 µm. Comparative example 1:
    [0079] [00079] Type Celgard 2320, dry three-layer membrane (polypropylene / polyethylene / polypropylene), thickness 20 μm. Comparative example 2:
    [0080] [00080] Type Tonen E 16 MMS, wet membrane (polyolefin), thickness 15 μm. Comparative example 3:
    [0081] [00081] Ceramic separator, thickness: 31 μm.
    [0082] [00082] To determine weight, thickness, puncture resistance, resistance to breakage propagation and Gurley indices, the following measurement methods were applied: Weight:
    [0083] [00083] Based on the test program EN 29073 - T1, to determine the grammage, three samples were punched with a size of 100x100 mm each, the samples were weighed and the measurement value multiplied by 100. Thickness:
    [0084] [00084] Based on the test program EN 29073 - T2, thicknesses were determined with a precision thickness measuring device model 2000U / Elektrik. The measured area imported in 2 cm2, the measured pressure, 1000 cN / cm2. Puncture resistance: This method is based on:
    [0085] [00085] "Battery Conference on Applications and Advances, 1999. The Fourteenth Annual", page 161 - 169.
    [0086] [00086] In this method, the necessary force is determined, with which a separator must be ordered under defined conditions, so that it loses its electrical insulation effect. The measurement arrangement is shown in figure 1. The separator S to be tested is placed between an anode A (graphite on copper foil, total thickness: 78 μm, commercially available) and a cathode C (nickel-manganese-cobalt oxide on film) aluminum, 71 μm thick, commercially available), to correct the arrangement in a battery cell. These three layers are placed on a hardened and polished M steel plate, on the upper side a rounded and equally hardened metal stamp (diameter = 6 mm) is placed on the sample and this metal stamp B is contacted with the plate. iron M. The pressure on the three layers (composite of battery components) is increased for so long, until a short circuit occurs, the separator S is also damaged and anode A and cathode C come into direct contact. The force on the metallic stamp B is measured, in which the electrical resistance R drops as an impact to less than 100,000 Ohm.
    [0087] [00087] The forces measured in the examples and comparative examples are shown in figure 2 in a diagram. It is recognized that the forces to be applied in examples 1 to 3 with 730 N or 885 N are clearly above the forces of 420 N, 415 N, 490 N in the comparative examples. The separators according to the invention, therefore, are significantly more stable than the separators of the prior art. Resistance to break propagation:
    [0088] [00088] Based on the test program DIN 53859, the resistance of the separators to the propagation of the rupture was determined. For this purpose, three samples were punched each in MD ("machine direction", direction of nonwoven fabric) and CD ("cross direction", orthogonal to the direction of nonwoven fabric) with the size of 75 x 50 mm and with a 50 mm notch. This is shown schematically in figure 6. The arms of the measurement samples formed by the notch are fixed to the fixing terminals of a tensile testing machine (distance from the terminal 50 mm) and separated with a removal speed of 200 mm / min. Since separators often do not continue to tear in the direction of the cut, measurement samples, which tear laterally, should also be considered. The average of the determined values was formed.
    [0089] [00089] Figures 3 and 4 show the values of resistance to the propagation of rupture measured in the examples and comparative examples. Here too, it can be recognized that the separators according to the invention are significantly more stable than the separators of the prior art. Gurley Index:
    [0090] [00090] Based on the test program (ISO 9237), the Gurley indices of the separators were determined using a standard densitometer of Gurley Densometers from Frank Prüfgerate GmbH (model F40450). The measured surface imported in 6.4516 cm2, the volume of air in 50 cm3. The values of the measured Gurley indices are shown in figure 5 and are below 150 s / 50 ml of air, preferably below 100 s / 50 ml of air.
    [0091] [00091] Figure 7 shows a scanning electron microscopy image of a separator according to the invention. In figure 7 it can be clearly recognized, how homogeneous and uniform is the coating that comprises cellulose derivatives.
    [0092] [00092] With regard to other advantageous configurations and developments of the study according to the invention, reference is made, on the one hand, to the general part of the specification and, on the other hand, to the attached embodiments.
    权利要求:
    Claims (11)
    [0001]
    Separator with a non-woven basic body, the basic body being provided with a coating, the coating containing particles of filler material and cellulose, the particles of filler material being distributed in the basic body superficially homogeneously and all the pores of the nonwoven are filled with the particles of filler material homogeneously in such a way that the separator predominantly displays medium pore sizes, which are smaller than the average diameter of the particles of filler material, the coating being contains flexible organic binder particles, the cellulose containing cellulose derivatives having a chain length of at least 100 repetition units and the filler particles and the flexible organic binder particles are linked together others through cellulose, characterized by the fact that the binder particles are particles of li elastomeric grease and particles of filler material are bonded, via the elastomeric binder particles, to the nonwoven or to each other.
    [0002]
    Separator according to claim 1, characterized by the fact that cellulose contains cellulose derivatives, which are endowed with cellulose ether and / or cellulose ester.
    [0003]
    Separator according to claim 1 or 2, characterized in that the coating contains nonionic surfactants, which contain alkylated octyl and / or nonylphenol ethoxylates and / or ethylene oxide / propylene oxide copolymers.
    [0004]
    Separator according to any one of claims 1 to 3, characterized in that the flexible organic particles of binder make up a proportion of at least 2% by weight of the coating.
    [0005]
    Separator according to any one of claims 1 to 4, characterized in that the binder particles consist of organic polymers, which are selected from the group polyester, polyamides, polyether, polycarboxylates, polycarboxylic acids, polyvinyl compounds, polyolefins, rubbers, halogenated polymers, polyvinylpyrrolidone, polyacrylic acid, polyacrylate, polymethacrylic acid, polymethacrylate, polystyrene, polyvinyl alcohol, polyvinyl acetate, polyacrylamide and copolymers of those mentioned above, cellulose and its derivatives, polyether, polyurethane, polyurethane, polyurethane, rubber, polystyrene, rubber, polyurethane, polyurethane, rubber, polyurethane, polyurethane, polyurethane, rubber, polyurethane, polyurethane, rubber, polyurethane, rubber, polyurethane, polyurethane, rubber, polyurethane. (SBR), latex, fluorinated polymers, chlorinated polymers, siloxanes, silyl compounds, silanes, unsaturated polymers, as well as copolymers and mixtures thereof.
    [0006]
    Separator according to any one of claims 1 to 5, characterized in that at least some particles of filler material are prepared from organic polymers, which are selected from the group of polyacetals, polycyclo-olefin copolymers, polyester, polyimides , polyether ketones, polycarboxylates, halogenated polymers, unsaturated polymers, polypropylene, polyethylene, polyvinylpyrrolidone, polyvinylidene fluoride, polyester, fluorinated polymers, chlorinated polymers, polytetrafluoroethylene, perfluor-ethylene-propylene (FEP), polyethylene, polystyrene, polystyrene polyether imides, polyether ketones, as well as copolymers and mixtures of the polymers mentioned above.
    [0007]
    Separator according to any one of claims 1 to 6, characterized in that at least some particles of filler material are formed as inorganic particles.
    [0008]
    Separator according to claim 7, characterized in that the inorganic particles are selected from the group consisting of metal oxides, metal hydroxides and silicates, especially aluminum oxides, silicon oxides, zeolites, titanates and / or perowskites.
    [0009]
    Separator according to any one of claims 1 to 8, characterized in that the nonwoven fibers are made from organic polymers, which are selected from the group of polybutyl terephthalate, polyethylene terephthalate, polyacrylonitrile, polyvinylidene fluoride, polyetherether ketone, polyethylene naphthalate, polysulfone, polyimide, polyether, polypropylene, polyethylene, polyoxymethylene, polyamide, polyvinylidene fluoride or polyvinylpyrrolidone.
    [0010]
    Separator according to any one of claims 1 to 9, characterized by the fact that the coating has irregularities, which protrude from the level at most 1 μm and / or the coating has recesses, which have a depth of at most 1 μm.
    [0011]
    Separator according to any one of claims 1 to 10, characterized in that the flexible organic binder particles have a softening point or a glassy point less than 20 ° Celsius.
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    同族专利:
    公开号 | 公开日
    US20130130092A1|2013-05-23|
    PL2603944T3|2020-01-31|
    HUE045568T2|2019-12-30|
    RU2554945C2|2015-07-10|
    EP2603944B1|2019-07-03|
    EP2603944A1|2013-06-19|
    WO2012019626A1|2012-02-16|
    KR20140003388A|2014-01-09|
    JP2013541128A|2013-11-07|
    BR112012033046A2|2016-12-20|
    RU2013110055A|2014-09-20|
    CN103026530A|2013-04-03|
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    法律状态:
    2019-01-15| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2019-03-12| B06T| Formal requirements before examination|
    2020-06-23| B09A| Decision: intention to grant|
    2020-09-24| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 10 (DEZ) ANOS CONTADOS A PARTIR DE 24/09/2020, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    PCT/EP2010/004912|WO2012019626A1|2010-08-11|2010-08-11|Separator with increased puncture resistance|
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