Fire retardant and oil-resistant potting for ev batteries

Abstract

The present invention relates to a battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of a polyisocyanate composition, and a polyol composition comprising at least one di- or trifunctional polyester or polyether polyol and at least flame retardant composition (FC). Furthermore, the present invention relates to a process for preparing the battery module according to the invention. The invention also relates to the use of a polyurethane cast elastomer or a polyurethane cast elastomer as defined above for producing a shaped body, in particular a battery module or a part of a battery module, such as for example an oil-cooled battery module or a part of an oil cooled battery module.

Description

[0001] 231460W001

[0002] Fire retardant and oil-resistant potting for EV batteries

[0003] The present invention relates to a battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of a polyisocyanate composition, and a polyol composition comprising at least one di- or trifunctional polyester or polyether polyol and at least flame retardant composition (FC). Furthermore, the present invention relates to a process for preparing the battery module according to the invention. The invention also relates to the use of a polyurethane cast elastomer or a polyurethane cast elastomer as defined above for producing a shaped body, in particular a battery module or a part of a battery module, such as for example an oil-cooled battery module or a part of an oil cooled battery module.

[0004] With the increasing use of larger power portable power tools and the widespread application of lithium batteries, single-cell lithium batteries have been unable to meet the requirements. Usually, lithium-ion batteries are installed and fixed into battery modules through insulating and flame-retardant bracket materials. The group then forms battery packs or modules in different series and parallel ways.

[0005] Safety is the biggest problem in the application of batteries. Although the performance of single cells is excellent, the application performance problems are outstanding after the formation of battery packs. If subjected to extreme external conditions, for example lithium-ion batteries are very easy to short-circuit and cause fire and explosion. Due to the resulting open flame and high temperature and high heat, it is very easy to ignite other nearby batteries. Safety accidents such as fire and even explosion of the entire battery pack occurred.

[0006] At present, the potting glue is poured into the gap of the battery pack to prevent the battery pack from burning. For example CN111607351 discloses a thermally conductive polyurethane potting sealant for batteries of new energy vehicles. The potting glue acts as a flame retardant by isolating oxygen. However, due to the poor sealing performance, the flame retardant effect of the existing potting compound is low.

[0007] Suitable potting materials furthermore have to be resistant towards the cooling medium. Cooling mediums typically are mixtures comprising for example long chain alkanes such as for example alkanes with 13 to 16 carbon atoms, cyclic alkanes, glycols, polyolefins, aromatic hydrocarbons and / or oils.

[0008] It was therefore an object of the present invention to provide a potting material for batteries with improved fire resistance and oil resistance and to provide the respective battery modules. Preferably, the potting material is characterized by low oil absorption, which can be measured by changes in mass or volume. The oil resistance of the potting material can for example be determined by changes in the mechanical properties, e.g., Shore hardness, tensile strength, or modulus of elasticity.231460W001

[0009] -2 - Furthermore, the material should preferably exhibit a mass change of less than 8%, preferably less than 4%, and particularly preferably less than 1 % when in contact with the cooling medium. The Shore hardness of the material should preferably change by less than 20%, more preferably less than 15%, and particularly preferably less than 10% after contact when in contact with the cooling medium, determined according to DIN ISO 48-4.

[0010] According to the present invention, this object has been solved by a battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0011] (i) a polyisocyanate composition;

[0012] (ii) a polyol composition comprising

[0013] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol, and

[0014] (ii.2) at least flame retardant composition (FC).

[0015] Preferably, the present invention relates to a battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0016] (i) a polyisocyanate composition;

[0017] (ii) a polyol composition comprising

[0018] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol, and

[0019] (ii.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0020] It has been surprisingly found that the battery modules according to the present invention have good flame retardant properties as well as improved oil resistance. According to the present invention, the battery can be potted with the polyurethane cast elastomer, so that the entire battery pack can be reduced in weight and a high anti-spreading property can be provided between battery cells. Further, it is possible to suppress deformation and reduction in strength due to shrinkage of urethane foam, which usually occur when a large amount of a flame retardant is contained. In addition, it is possible to suppress the influence of heat generated during curing on the battery life and the like.

[0021] The battery module according to the present invention comprises a potting compound, which comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0022] (i) a polyisocyanate composition;

[0023] (ii) a polyol composition comprising

[0024] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol, and

[0025] (ii.2) at least flame retardant composition (FC).231460W001

[0026] - 3 - The polyurethane cast elastomer used in the battery modules according to the present invention has excellent electrical insulation and flame resistance. It has good adhesion to steel, aluminum, copper, tin, rubber, plastic, thermoplastic and thermoset materials, wood and other materials.

[0027] The polyurethane cast elastomer according to the present invention preferably has a shore hardness in the range of from Shore A60 to D85, in particular A80 to Shore D85, more preferable in the range of from 40D to 75D, in particular in the range of from 55D to 70D. The Shore hardness may be determined according to DIN ISO 48-4.

[0028] Preferably, the polyurethane cast elastomer according to the present invention preferably has a thermal conductivity in the range of from 0.01 to 0.80 W / (mK), more preferable in the range of from 0.1 to 0.6 W / (mK), in particular in the range of from 0.2 to 0.40 W / (mK). Unless otherwise noted, the thermal conductivity is determined according to ASTM D5470.

[0029] Preferably, the polyurethane cast elastomer has a density of > 500 kg / m3, in particular in the range of from 800 kg / m3to 1700 kg / m3, more preferable in the range of from 1000 kg / m3to 1500 kg / m3. Unless otherwise noted, the density is determined according to DIN EN ISO 1183-1.

[0030] The polyol composition used for the preparation of the polyurethane cast elastomer comprises a flame retardant composition (FC). Suitable flame retardants are in principle known. It has been found that advantageously, mixtures comprising two or more flame retardants can be used. According to a further embodiment, the present invention is also directed to the battery module as disclosed above, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0031] It should be noted that the fillers preferably should have a particle size of less than 200um, more preferably of less than 150um, and particularly preferably of less than 100um.

[0032] The amount of the flame retardants used may vary. It has been found that it is advantageous to use the flame retardants in an amount in the range of from 20 to 80% based on the weight of the polyol composition, preferably in an amount in the range of from 25 to 65% based on the weight of the polyol composition, in particular in an amount in the range of from 30 to 56% based on the weight of the polyol composition. According to a further embodiment, the present invention is also directed to the battery module as disclosed above, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

[0033] Suitable phosphorous containing flame retardant (F1) are in principle known to the person skilled in the art. Examples of the phosphorus-based flame retardant include, but are not particularly limited to, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, other aromatic phosphate esters, aromatic condensed231460W001

[0034] - 4 -phosphate esters, and diphenyl monophosphate phosphate, orthoxenyl, 2-naphthyldiphenyl phosphate, 10-benzyl-9,10-dihydroxy-9-oxa-10-phosphaphenanthrene-10-oxide, triphenylphosphine oxide, 5,5-dimethyl-2- (2 ' -phenylphe-noxy) -1,3,2-dioxaphosphorinane-2-oxide, tris (chloropropyl) phosphate, tris (dichloropropyl) phosphate and the like.

[0035] Suitable phosphorous containing flame retardants may for example be selected from ammonium polyphosphates.

[0036] Also metal hydroxides which may be used as flame retardant (F2) are in principle known. Suitable are for example magnesium hydroxide or aluminium hydroxide, in particular aluminium hydroxide.

[0037] Also the ratio of flame retardants (F1) and (F2) may vary. Preferably, the ratio of flame retardants (F1) and (F2) may be in the range of from 0.1:1 to 1:01, more preferable in the range of from 0.5:1 to 1 :0.5.in particular in the range of from 0.8:1 to 1:0.8.

[0038] The polyol composition may also comprise further components, such as for example further flame retardants or also fillers which may also act as flame retardant. According to a further embodiment, the present invention is also directed to the battery module as disclosed above, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides such as for example boron nitride, or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous such as for example graphite, or cyclotriphosphazene.

[0039] According to the present invention, the polyisocyanate composition comprises one or more polyisocyanates, in particular one or more Diisocyanaten. According to the present invention, also prepolymers may be used. Suitable polyisocyanates are in principle known to the person skilled in the art.

[0040] As organic isocyanates there may be used commonly known aromatic, aliphatic, cycloaliphatic and / or araliphatic isocyanates, preferably diisocyanates, for example 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1 ,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate, 3,3‘-dimethyldiphenyl diisocyanate, 1 ,2-diphenylethane diisocyanate and / or phenylene diisocyanate, tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methylpentamethylene 1 ,5-diisocyanate, 2— ethylbutylene 1,4-diisocyanate, pentamethylene 1 ,5-diisocyanate, butylene 1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocy-anatomethylcyclohexane (isophorone diisocyanate, IPDI), 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohex-ane (H12MDI), 2,6-diisocyanatohexanecarboxylic ester, 1,4- and / or 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1— methyl— 2,4— and / or -2,6-cyclohexane diisocyanate and / or 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate, preferably 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1 ,5-naph-thylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), hexamethylene diisocyanate, 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane, and / or IPDI, more particularly 4,4'-MDI and / or hexamethylene diisocyanate and / or H12MDI.231460W001

[0041] - 5- According to a further embodiment, the present invention is also directed to the polyurethane composition as disclosed above, wherein the polyisocyanate composition comprises a polyisocyanate selected from the group consisting of 2,2'-, 2, 4'- and 4,4'-diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate or prepolymers of diphenylmethane diisocyanate or polymeric diphenylmethane diisocyanate.

[0042] The polyol composition comprises at least one di- or trifunctional polyester or polyether polyol. Suitable di- or trifunctional polyester or polyether polyols are in principle known to the person skilled in the art. Suitable polyesterols or polyetherols, which are usually also summarized by the term "polyols”, typically have molecular weights (Mn) of from 500 to 8000, preferably from 600 to 6000, in particular from 800 to less than 3000 g / mol.

[0043] Polyetherpolyols are preferably used, for example those based on generally known initiator substances and conventional alkylene oxides, for example ethylene oxide, propylene oxide and / or butylene oxide, preferably polyetherols based on 1 ,2-propylene oxide and ethylene oxide and in particular polyoxytetramethylene glycols

[0044] In principle, any suitable polyester polyol known to a person skilled in the art is useful for the purposes of the present invention. Suitable polyester polyols are for example based on carboxylaic acids such as for example an acid selected from the group consisting of succinic acid, azelaic acid, sebacic acid, and dodecanoic acid and dimer acids.

[0045] Typically, the polyester polyol is based on a polyhydric alcohol. Suitable polyhydric alcohols include, for example, polyhydric aliphatic alcohols, for example aliphatic alcohols having 2, 3, 4 or more OH groups, for example 2 or 3 OH groups. Suitable aliphatic alcohols for the purposes of the present invention include, for example, C2 to C12 alcohols, preferably C2 to C8 alcohols and most preferably C2 to C6 alcohols. It is preferable for the purposes of the present invention for the polyhydric alcohol to be a diol, and suitable diols are known per se to a person skilled in the art.

[0046] Suitable aliphatic C2 to 06 diols include, for example, ethylene glycol, diethylene glycol, 3-oxapentane-1,5-diol, 1,3-propanediol, 1 ,2-propanediol, dipropylene glycol, 1 ,4-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, 2-methyl-1 ,3-pro-panediol and 3-methyl-1 ,5-pentanediol. It is further preferable for the polyhydric alcohol to be selected from the group consisting of ethylene glycol, diethylene glycol, 1 ,3-propanediol and 1 ,4-butanediol.

[0047] Alcohols having three or more OH groups can also be used to enhance the functionality of the polyester polyols. Examples of alcohols having three or more OH groups are glycerol, trimethylolpropane and pentaerythritol. It is also possible to use oligomeric or polymeric products having two or more hydroxyl groups. Examples thereof are polytetrahydrofuran, polylactones, polyglycerol, polyetherols, polyesterol or a, co-di hydroxy poly butadiene.

[0048] It is also possible for the purposes of the present invention to employ a polyhydric alcohol at least partly obtained from renewable raw materials.231460W001

[0049] - 6 - The present invention may also utilize a mixture of two or more polyhydric alcohols. The present invention may also utilize a mixture of two or more dicarboxylic acids.

[0050] Preferably, the polyol composition comprises oil based polyols in an amount of less than 2% by weight based on the polyol composition, more preferably less than 1% by weight, in particular less than 0.5%by weight, more preferable less than 0.1% by weight. The polyol composition may also be free of oil-based polyols.

[0051] Processes for preparing polyester polyols by polycondensation of the corresponding hydroxy compounds with dicarboxylic acids preferably at elevated temperature and reduced pressure preferably in the presence of known catalysts are common knowledge and have been extensively described.

[0052] Processes for preparing polyurethanes are likewise common knowledge. For example, thermoplastic polyurethanes are obtainable by reaction of isocyanates with polyester polyol and optionally chain-extending agents having a molecular weight of 50 to 499 g / mol in the presence or absence of catalysts and / or customary assistants.

[0053] The ratio of the components employed may in principle vary between wide limits. This ratio of the components employed is typically described by the ratio of NCO groups to OH groups, the OH groups being the sum total of the OH groups for the employed polyester polyol, chain extender and any further additives.

[0054] The ratio of NCO to OH groups in the present invention is in the range from 0.9 to 1.1 for example and is preferably in the range from 0.95 to 1.05.

[0055] Preferably, polyurethanes are prepared according to the present invention by reacting the isocyanate with the polyester polyol and optionally further isocyanate-reactive compounds and optionally chain-extending agents in the presence or absence of catalysts and / or customary assistants. Plasticizers may also be employed in the present invention for example. The plasticizers which are used, which is preferable according to the present invention, may have isocyanate-reactive groups. However, it is likewise possible for the plasticizers employed not to have any isocyanatereactive groups. Suitable plasticizers are known per se, see for instance the Plastics Additive Handbook, 5th edition, H. Zweifel, ed, Hanser Publishers, Munich, 2001.

[0056] According to the present invention, the polyurethane cast elastomer preferably is a cross-linked polyurethane. Preferably, the polyurethane cast elastomer used according to the present invention is not thermopl astically processable.

[0057] Preferably, the polyurethane cast elastomer exhibits a mass change of less than 8%, preferably less than 4%, and particularly preferably less than 1% when in contact with a cooling medium after 6 month at 80°C storage. The Shore hardness of the material should preferably change by less than 20%, more preferably less than 15%, and particularly preferably less than 10% after contact when in contact with the cooling medium after 6 month at 80°C storage.231460W001

[0058] - 7 - According to a further aspect, the present invention is also directed to a process for producing a battery module comprising a potting compound, the process comprising preparing a polyurethane cast elastomer comprising the reaction of the components (I) to (ii):

[0059] (I) a diisocyanate composition;

[0060] (ii) a polyol composition comprising

[0061] (ii.1 ) at least one difunctional or trifunctional polyester or polyether polyol, and

[0062] (ii.2) at least one flame retardant composition (FC).

[0063] Furthermore, the presort invention is also directed to a process for producing a battery module comprising a potting compound, the process comprising preparing a polyurethane cast elastomer comprising the reaction of the components (I) to (ii):

[0064] (I) a diisocyanate composition;

[0065] (ii) a polyol composition comprising

[0066] (ii.1 ) at least one difunctional or trifunctional polyester or polyether polyol, and

[0067] (ii.2) at least one flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0068] Processes for the preparation of battery modules are in principle known to the person skilled in the art.

[0069] Preferably, the process according to the invention comprises a step of preparing a reaction mixture form the diisocyanate composition and the polyol composition comprising the at least one difunctional or trifunctional polyester or polyether polyol, and the at least one flame retardant composition (FC). The reaction mixture preferably has a viscosity in the range of from 0.1 to 10 Pas to allow for the preparation of the battery module, more preferable in the range of from 0.5 to 5 Pas, in particular in the range of from 1 to 3 Pas.

[0070] According to a further aspect, the present invention is also directed to the use of a polyurethane cast elastomer as disclosed above or a polyurethane cast elastomer obtainable or obtained by the process as disclosed above for producing a shaped body.

[0071] According to a further embodiment, the present invention is also directed to the use as disclosed above, wherein the polyurethane cast elastomer has a Shore hardness in the range of from Shore A80 to Shore D85.

[0072] According to a further embodiment, the present invention is also directed to the use as disclosed above, wherein the polyurethane cast elastomer has a density of > 500 g / L.231460W001

[0073] - 8 - The thermal conductivity of polyurethane cast elastomer used as potting material for a battery according to the present invention is preferably in the range of from 0.01 to 0.80 W / (mK). Thus, even when the battery is ignited, it is possible to effectively prevent the adjacent battery from burning, and to release the heat generated in the battery to some extent because the thermal conductivity is not too low.

[0074] According to a further embodiment, the present invention is also directed to the use as disclosed above, wherein the polyurethane cast elastomer has a thermal conductivity in the range of from 0.01 to 0.80 W / (mK).

[0075] According to a further aspect, the present invention is also directed to a shaped body, comprising a polyurethane cast elastomer as disclosed above or a polyurethane cast elastomer obtainable or obtained by the process as disclosed above.

[0076] Preferably, the shaped body is a battery module or a part of a battery module, in particular wherein the shaped body is an oil-cooled battery module or a part of an oil cooled battery module. According to a further embodiment, the present invention is also directed to the shaped body as disclosed above, wherein the shaped body is a battery module or a part of a battery module. The present invention is also directed the shaped body as disclosed above, wherein the shaped body is a component of the battery module that specifically fills a space that come in contact with the coolants and requiring the functionality of both chemical coolants resistance as well as flame retardant performance. In particular wherein the shaped body is an oil-cooled battery module or a part of an oil cooled battery module.

[0077] Listed herein after are illustrative embodiments of the present invention, though these do not restrict the present invention. More particularly, the present invention also encompasses those embodiments which arise from the dependency references and hence combinations specified hereinafter.

[0078] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The composition of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The composition of any one of embodiments 1, 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

[0079] 1. A battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0080] 0) a polyisocyanate composition;

[0081] (ii) a polyol composition comprising231460W001

[0082] -9 - (ii.1 ) at least one di- or trifunctional polyester or polyether polyol

[0083] (II.2) at least flame retardant composition (FC).

[0084] 2. A battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0085] (i) a polyisocyanate composition;

[0086] (ii) a polyol composition comprising

[0087] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol

[0088] (ii.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0089] 3. The battery module according to embodiment 1 or 2, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from the group consisting of triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, other aromatic phosphate esters, aromatic condensed phosphate esters, and diphenyl monophosphate phosphate, orthoxenyl, 2-naph- thyldiphenyl phosphate, 10-benzyl-9,10-dihydroxy-9-oxa-10-phosphaphenanthrene-10-oxide, triphenylphosphine oxide, 5,5-dimethyl-2- (2 ' -phenylphenoxy) -1,3,2-dioxaphosphorinane-2-oxide, tris (chloropropyl) phosphate, and tris (dichloropropyl) phosphate.

[0090] 4. The battery module according to any one of embodiments 1 to 3, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from ammonium polyphosphates and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0091] 5. The battery module according to any one of embodiments 1 to 4, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

[0092] 6. The battery module according to any one of embodiments 1 to 5, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous.

[0093] 7. A process for producing a battery module comprising a potting compound, the process comprising preparing a polyurethane cast elastomer comprising the reaction of the components (i) to (ii):

[0094] (i) a diisocyanate composition;

[0095] (ii) a polyol composition comprising

[0096] (ii.1 ) at least one difunctional or trifunctional polyester or polyether polyol231460W001

[0097] - 10- (ii.2) at least one flame retardant composition (FC).

[0098] 8. A process for producing a battery module comprising a potting compound, the process comprising preparing a polyurethane cast elastomer comprising the reaction of the components (i) to (ii):

[0099] (i) a diisocyanate composition;

[0100] (ii) a polyol composition comprising

[0101] (ii.1 ) at least one difunctional or trifunctional polyester or polyether polyol

[0102] (ii.2) at least one flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0103] 9. The process according to embodiment 7 or 8, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from the group consisting of triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, other aromatic phosphate esters, aromatic condensed phosphate esters, and diphenyl monophosphate phosphate, orthoxenyl, 2-naphthy Idi- phenyl phosphate, 10-benzy I-9, 10-dihydroxy-9-oxa-10-phosphaphenanthrene-10-oxide, triphenylphosphine oxide, 5,5-dimethyl-2- (2 ' -phenylphenoxy) -1,3,2-dioxaphosphorinane-2-oxide, tris (chloropropyl) phosphate, and tris (dichloropropyl) phosphate.

[0104] 10. The process according to any one of embodiments 7 to 9, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from ammonium polyphosphates and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0105] 11. The process according to any one of embodiments 7 to 10, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

[0106] 12. The process according to any one of embodiments 1 to 5, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous.

[0107] 13. The use of a polyurethane cast elastomer a obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0108] (i) a polyisocyanate composition;

[0109] (ii) a polyol composition comprising

[0110] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol,

[0111] (ii.2) at least flame retardant composition (FC),

[0112] for producing a shaped body.231460W001

[0113] - 11 -

[0114] 14. The use of a polyurethane cast elastomer a obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0115] (i) a polyisocyanate composition;

[0116] (ii) a polyol composition comprising

[0117] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol,

[0118] (ii.2) at least flame retardant composition (FC) at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides, for producing a shaped body.

[0119] 15. The use according to embodiment 13 or 14, wherein the polyurethane cast elastomer has a Shore hardness in the range of from Shore A60 to Shore D85.

[0120] 16. The use according to embodiment 13 or 14, wherein the polyurethane cast elastomer has a Shore hardness in the range of from Shore A60 to Shore D85 determined according to DIN ISO 48-4.

[0121] 17. The use according to any one of embodiments13 to 16, wherein the polyurethane cast elastomer has a density of more than 500 g / L.

[0122] 18. The use according to any one of embodiments 13 to 17, wherein the polyurethane cast elastomer has a thermal conductivity in the range of from 0.01 to 0.80 W / (mK).

[0123] 19. The use according to any one of embodiments 13 to 17, wherein the polyurethane cast elastomer has a thermal conductivity in the range of from 0.01 to 0.80 W / (mK), determined according to ASTM D5470.

[0124] 20. The use according to any one of embodiments 13 to 19, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from the group consisting of triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, other aromatic phosphate esters, aromatic condensed phosphate esters, and diphenyl monophosphate phosphate, orthoxenyl, 2- naphthyldiphenyl phosphate, 10-benzy I-9, 10-dihydroxy-9-oxa-10-phosphaphenanthrene-10-oxide, triphenylphosphine oxide, 5,5-dimethyl-2- (2 ' -phenylphenoxy) -1,3,2-dioxaphosphorinane-2-oxide, tris (chloropropyl) phosphate, and tris (dichloropropyl) phosphate.

[0125] 21. The use according to any one of embodiments 13 to 20, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from ammonium polyphosphates and a second flame retardant (F2) selected from the group consisting of metal hydroxides.231460W001

[0126] - 12 - 22. The use according to any one of embodiments 13 to 21, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

[0127] 23. The use according to any one of embodiments 13 to 22, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous.

[0128] 24. A shaped body, comprising a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (I) to (ii):

[0129] (I) a polyisocyanate composition;

[0130] (ii) a polyol composition comprising

[0131] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol,

[0132] (ii.2) at least flame retardant composition (FC).

[0133] 25. A shaped body, comprising a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (I) to (ii):

[0134] (I) a polyisocyanate composition;

[0135] (ii) a polyol composition comprising

[0136] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol,

[0137] (ii.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0138] 26. The shaped body according to embodiment 24 or 25, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from the group consisting of triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, other aromatic phosphate esters, aromatic condensed phosphate esters, and diphenyl monophosphate phosphate, orthoxenyl, 2-naph- thyldiphenyl phosphate, 10-benzyl-9,10-dihydroxy-9-oxa-10-phosphaphenanthrene-10-oxide, triphenylphosphine oxide, 5,5-dimethyl-2- (2 ' -phenylphenoxy) -1,3,2-dioxaphosphorinane-2-oxide, tris (chloropropyl) phosphate, and tris (dichloropropyl) phosphate.

[0139] 27. The shaped body according to any one of embodiments 24 to 26, wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from ammonium polyphosphates and a second flame retardant (F2) selected from the group consisting of metal hydroxides.231460W001

[0140] - 13 - 28. The shaped body according to any one of embodiments 24 to 27, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

[0141] 29. The shaped body according to any one of embodiments 24 to 28, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous.

[0142] 30. The shaped body according to any one of embodiments 24 to 29, wherein the shaped body is a battery module or a part of a battery module, in particular wherein the shaped body is an oil-cooled battery module or a part of an oil cooled battery module.

[0143] 31. A battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (I) to (II):

[0144] (I) a polyisocyanate composition;

[0145] (II) a polyol composition comprising

[0146] (II.1) at least one di- or trifunctional polyester or polyether polyol,

[0147] (II.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0148] 32. The battery module according to embodiment 31 , wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from ammonium polyphosphates and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0149] 33. The battery module according to embodiment 31 or 32, wherein the average particle size of the phosphorous containing flame retardant (F1) and the flame retardant (F2) is less than 200um.

[0150] 34. The battery module according to any one of embodiments 31 to 33, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

[0151] 35. The battery module according to any one of embodiments 31 to 34, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous.231460W001

[0152] - 14- 36. The battery module according to any one of embodiments 31 to 35, wherein the polyisocyanate composition comprises a polyisocyanate selected from the group consisting of 2,2'-, 2, 4'- and 4,4'-diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate or prepolymers of diphenylmethane diisocyanate or polymeric diphenylmethane diisocyanate.

[0153] 37. The battery module according to any one of embodiments 31 to 36, wherein the potting compound exhibits a mass change of less than 8%, when in contact with a cooling medium after 6 month at 80°C storage.

[0154] 38. The battery module according to any one of embodiments 31 to 37, wherein the Shore hardness of the potting compound changes by less than 20%, after contact when in contact with the cooling medium after 6 month at 80°C storage.

[0155] 39. A process for producing a battery module comprising a potting compound, the process comprising preparing a polyurethane cast elastomer comprising the reaction of the components (i) to (ii):

[0156] (i) a diisocyanate composition;

[0157] (ii) a polyol composition comprising

[0158] (ii.1 ) at least one difunctional or trifunctional polyester or polyether polyol,

[0159] (ii.2) at least one flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

[0160] 40. The use of a polyurethane cast elastomer a obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):

[0161] (i) a polyisocyanate composition;

[0162] (ii) a polyol composition comprising

[0163] (ii.1 ) at least one di- or trifunctional polyester or polyether polyol,

[0164] (ii.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides,

[0165] for producing a shaped body.

[0166] 41. The use according to embodiment 40, wherein the polyurethane cast elastomer has a Shore hardness in the range of from Shore A60 to Shore D85, determined according to DIN ISO 48-4.

[0167] 42. The use according to embodiment 40 or 41 , wherein the polyurethane cast elastomer has a density of more than 500 kg / m3, determined according to DIN EN ISO 1183-1.231460W001

[0168] - 15- 43. The use according to any one of embodiments 40 to 42, wherein the polyurethane cast elastomer has a thermal conductivity in the range of from 0.01 to 0.80 W / (mK), determined according to ASTM D5470.

[0169] The invention is further described by examples. The examples relate to practical and in some cases preferred embodiments of the invention that do not limit the scope of the invention.

[0170] Examples

[0171] 1. Materials used

[0172] Polyol 1 aliphatic polyester polyol composed of adipic acid, ethylene glycol, diethylene glycol and glycerin with a molecular weight of 2500 g / mol, a functionality of 2.64 and and an OH number of 60 mgKOH / g

[0173] Polyol 2 aromatic polyester polyol composed of pthathlic acid, oleic acid, diethylene glycol and glycerin with a molecular weight of 570 g / mol, a functionality of 2.5 and an OH number of 242 mgKOH / g Polyol 3 polyether polyol based on propylene oxide, ethylene oxide and glyverin with a molecular weight of 4400 g / mol, a functionality of 2.72 and an OH number of 26.5 mgKOH / g Polyol 4 polyether polyol based on propylene oxide, ethylene oxide and glycerin with a molecular weight of 5200 g / mol, a functionality of 2.42, and an OH number of 35 mgKOH / g.

[0174] Polyol 5 polyether polyol based on propylene oxide and glycerin with a molecular weight of 420 g / mol, a functionality of 2.99, and an OH number of 400 mgKOH / g.

[0175] Polyol 6 castor oil with a molecular weight of 912 g / mol, a functionality of 2.6 and an OH number of 160.5 mgKOH / g.

[0176] Polyol 7 polyether polyol based on ethylene oxide and trimethyol propane oxide with a molecular weight of 180 g / mol, a functionality of 2.98 and an OH number of 935 mgKOH / g.

[0177] Polyol 8 polyether polyol based on ethylene oxide and propylene glycol with a molecular weight of 1070 g / mol, a functionality of 1.98 and an OH number of 104 mgKOH / g.

[0178] Polyol 9 polyether polyol based on propylene oxide and glycerin with a molecular weight of 210 g / mol, a functionality of 3 and an OH number of 805 mgKOH / g.

[0179] Chain extender 1 1 ,4-Butandiol

[0180] Chain extender 2 Glycerin

[0181] Catalyst 1 DABCO Catalyst

[0182] Catalyst 2 Tri azin Catalyst

[0183] Catalyst 3 Tin catalyst231460W001

[0184] - 16 - Flame retardant 1 ammonium polyphosphate, D50= 17 pm, D95= 50 pm

[0185] Flame retardant 2 aluminum hydroxide, D50= 17.5 pm, D90= 47-75 pm

[0186] Additive 1 K-Ca-Na-Zeolite in castor oil

[0187] Additive 2 Dispersing agent

[0188] Additive 3 Dispersing agent

[0189] Additive 4 Dispersing agent

[0190] Additive 5 Dispersing agent

[0191] Isocyanate 1 An MDI and PMD isocyanate prepolymer with an NCO content of 22.9%, an average molecular weight of 269 g / mol and an average functionality of 2.16. The viscosity is 660 mPas at 25°C. Isocyanate 2 An MDI isocyanate prepolymer with an NCO content of 26.2% , a molecular weight of 256 g / mol and a functionality of 2.05. The viscosity is 125 mPas at 25°C.

[0192] Isocyanate 3 An MDI isocyanate prepolymer with an NCO content of 24.6%, and an average functionality of 2.12. The viscosity is 390 mPas at 25°C.

[0193] The polyurethane material was produced by preparing the polyol and isocyanate components and mixing both for 45s at 1600 rpm under vacuum. The mixed material was casted into a mould and the material reacted for 15 min at 60°C. From the plaques small samples were stamped out and stored at 80°C in oil up to 6 month. Once the material was taken out, the residue oil was wiped off and mechanical tests were conducted after storing at room temperature for one day.

[0194]

[0195] 231460W001

[0196] - 17 -

[0197]

[0198]

[0199] Literature cited:

[0200] CN111607351

Claims

231460W001- 18 - Claims1. A battery module comprising a potting compound, wherein the potting compound comprises a polyurethane cast elastomer obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):(i) a polyisocyanate composition;(ii) a polyol composition comprising(ii.1 ) at least one di- or trifunctional polyester or polyether polyol,(ii.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

2. The battery module according to claim 1 , wherein the flame retardant composition (FC) comprises at least one phosphorous containing flame retardant (F1) selected from ammonium polyphosphates and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

3. The battery module according to claim 1 or 2, wherein the average particle size of the phosphorous containing flame retardant (F1) and the flame retardant (F2) is less than 200um.

4. The battery module according to any one of claims 1 to 3, wherein the polyol composition comprises the flame retardant (F1) and (F2) in an amount in the range of from 20 to 80% by weight based on the weight of the polyol composition.

5. The battery module according to any one of claims 1 to 4, wherein the polyol composition further comprises a filler (F3) selected from metal hydroxides, metal oxides, metal carbonates or inorganic nitrides or organic compounds with cyclic moieties comprising carbon, nitrogen, and / or phosphorous.

6. The battery module according to any one of claims 1 to 5, wherein the polyisocyanate composition comprises a polyisocyanate selected from the group consisting of 2,2'-, 2, 4'- and 4,4'-dipheny Imethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate or prepolymers of diphenylmethane diisocyanate or polymeric diphenylmethane diisocyanate.

7. The battery module according to any one of claims 1 to 6, wherein the potting compound exhibits a mass change of less than 8%, when in contact with a cooling medium after 6 month at 80°C storage.231460W001- 19 - 8. The battery module according to any one of claims 1 to 7, wherein the Shore hardness of the potting compound changes by less than 20%, after contact when in contact with the cooling medium after 6 month at 80°C storage.

9. A process for producing a battery module comprising a potting compound, the process comprising preparing a polyurethane cast elastomer comprising the reaction of the components (i) to (ii):(i) a diisocyanate composition;(ii) a polyol composition comprising(ii.1 ) at least one difunctional or trifunctional polyester or polyether polyol,(ii.2) at least one flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides.

10. The use of a polyurethane cast elastomer a obtainable or obtained by a process comprising the reaction of at least the components (i) to (ii):(i) a polyisocyanate composition;(ii) a polyol composition comprising(ii.1 ) at least one di- or trifunctional polyester or polyether polyol,(ii.2) at least flame retardant composition (FC) comprising at least one phosphorous containing flame retardant (F1) and a second flame retardant (F2) selected from the group consisting of metal hydroxides,for producing a shaped body.

11. The use according to claim 10, wherein the polyurethane cast elastomer has a Shore hardness in the range of from Shore A60 to Shore D85, determined according to DIN ISO 48-4.

12. The use according to claim 10 or 11, wherein the polyurethane cast elastomer has a density of more than 500 kg / m3, determined according to DIN EN ISO 1183-1.

13. The use according to any one of claims 10 to 12, wherein the polyurethane cast elastomer has a thermal conductivity in the range of from 0.01 to 0.80 W / (mK), determined according to ASTM D5470.

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