Insulating material for electrochemical cells

Abstract

The invention relates to a thermal insulation material for an electrochemical cell, preferably for a lithium ion cell, comprising a thermal insulation layer comprising a first textile wherein the first textile has a coating comprising aerogel particles and at least one at least partially water-soluble binder.

Description

Field of the Invention

[0001] The present invention relates to a heat-insulating material for an electrochemical cell, preferably for a lithium-ion battery, an electrochemical cell, preferably a lithium-ion battery, which is heat-insulated by the heat-insulating material of the present invention, and a battery module and / or a battery system, wherein at least two electrochemical cells are heat-insulated from each other by the heat-insulating material of the present invention. The present invention also relates to a method for manufacturing the heat-insulating material and the use of the heat-insulating material. Background Art

[0002] Heat-insulating materials for electrochemical cells to prevent or at least delay "thermal runaway" are known. Thermal runaway has a high safety risk. Therefore, the safety standards for lithium-ion batteries also include combustion tests. In this test, the battery cells in the battery module are made to experience thermal runaway, and in this case, it is judged whether ignition is caused by heat propagation to other battery cells. To reduce this risk, refractory materials or heat-insulating materials, that is, materials with high heat-insulating properties, are usually provided between the battery cells.

[0003] Traditional heat-insulating materials (such as foam boards or fiber boards) can withstand high temperatures, but their heat-insulating ability is relatively low. Therefore, for such materials, in order to ensure efficient heat management, the thickness of the insulator needs to be set relatively high. However, the space requirements of the battery module limit the space available for the insulator between the battery cells in the module. Refractory materials such as mica or ceramic plates can also withstand high temperatures, but they are relatively incompressible and have low heat-insulating ability. Therefore, such materials are not suitable for battery systems in which the battery cells expand and contract during operation, such as pouch cells and prismatic cells.

[0004] It is also desirable to control the total weight of the battery module without reducing the thermal runaway propagation tolerance, flame retardancy or mechanical properties of the battery module.

[0005] To achieve good heat-insulating effects, the use of aerogels with extremely high heat-insulating properties has been proposed in the prior art. Aerogels are a class of porous materials with characteristics of low density, open-cell structure, large specific surface area and nano-scale pore size. The way of its heat-insulating effect is that: low density causes heat conduction to occur over a long distance along the framework structure. In addition, the large pore volume and extremely small pore size minimize convection. Aerogels can also be equipped with dopants that absorb or scatter infrared rays (IR) to enhance the heat-insulating effect. The thermal resistance value of aerogel materials is usually 2 to 6 times higher than that of other common heat-insulating materials (such as foams, glass fibers, etc.). Therefore, aerogels can enhance effective heat shielding and thermal insulation without significantly increasing the thickness or weight of the heat-insulating layer.

[0006] There is a desire to obtain a heat-insulating material for thermal management of electrochemical cells, preferably lithium-ion batteries, which is suitable for heat insulation of each battery cell, battery module, and / or battery system, and has the characteristics of high heat-insulating ability, low thickness, and low weight. In addition, considering sustainability, it is desirable for the heat-insulating material to have characteristics that facilitate recycling.

[0007] US2012 / 0142802 A discloses an open-cell foam filled with aerogel particles. Oikawa's US 2019 / 0161909A has disclosed a heat-insulating panel using non-woven fabric and aerogel. However, the materials described in these documents do not have both the thermal characteristics, fire-resistant characteristics, mechanical characteristics, and hydrophobic characteristics required when applied to battery thermal management components. In addition, these materials are not easily recyclable.

[0008] WO2021142169 A1 discloses a battery thermal management component, which includes: a first thermal protection layer, and at least one elastic layer containing one or several organic materials. The thermal protection layer may include an aerogel composition, which is preferably a silica-aerogel composition. The aerogel composition may further contain an adhesive, where the adhesive includes adhesives, resins, cements, foams, and polymers. The thermal management component is not easily recyclable.

[0009] US2021257690A1 discloses a component for a battery, which includes

[0010] a thermal management multilayer film disposed on the surface of an electrochemical cell, wherein the thermal management multilayer film includes the following parts:

[0011] - a heat-insulating layer,

[0012] - a first heat distribution layer disposed on a first side of the heat-insulating layer, and

[0013] - a second heat distribution layer disposed on a second side of the heat-insulating layer.

[0014] The heat-insulating layer may contain non-woven fabric made of, for example, glass fibers in combination with aerogel and an adhesive. Among them, the adhesive of the glass fiber layer includes epoxides, polyamides, polyimides, polyesters such as polybutylene terephthalate, polyethylene, polypropylene, polystyrene, polycarbonate, polysulfone, polyurethane, silicone, and vinyl ester. The heat-insulating layer is not easily recyclable.

[0015] In addition, commercially available aerogel-based thermal insulation materials, such as the aerogel felt with the model number SACB-0-6 from Tradematt (Henan) Industry Co., Ltd., or the Nasbis thermal insulation sheet EYGY0912QN3P from Panasonic Industrial Devices Co., Ltd., also have the drawback of generating dust. Therefore, the Nasbis thermal insulation sheet needs to be encapsulated, which, however, results in poor compressibility.

[0016] KR 2019 0143300A describes an aerogel thermal insulation composition, which includes aerogel powder, fibrous thermal insulation material, and an organic-inorganic composite binder. The fibrous thermal insulation material can be composed of long fibers, short fibers, or a mixture of long fibers and short fibers. The aerogel thermal insulation composition can be manufactured by mixing aerogel with the fibrous insulation material and the organic-inorganic binding material. A fibrous layer serving as a carrier can be provided on one or both sides of the aerogel insulation composition. This fibrous layer is relatively thin (10 - 40 μm), which results in insufficient mechanical strength and compressibility and makes it difficult to compensate for the thickness fluctuations of battery cells. In addition, the fibers in the binder layer reduce the thermal insulation performance. Also, the long fibers are prone to entanglement, affecting the recyclability characteristics of the thermal insulation composition.

[0017] EP3281968 (A1) describes a composition containing aerogel, which includes aerogel, a water-soluble binder material, a foaming agent, and a solvent, where the solvent includes water and a polar organic solvent. The composition preferably includes fibers. The composition containing aerogel can be applied to a carrier. Here, the fibers in the binder layer also reduce the thermal insulation. In addition, the foaming agent increases the combustion hazard and / or is harmful to the environment.

[0018] The object of the present invention is to provide a thermal insulation material for the thermal management of electrochemical cells (preferably lithium-ion batteries), battery modules, and / or battery systems, which is suitable for the thermal insulation of the aforementioned products and can combine high thermal insulation ability with low thickness and low weight. In addition, the thermal insulation material should have the characteristics of being easily recyclable and meet the requirements for electrochemical cells regarding dynamic mechanical stability and thermal insulation ability under a compressed state. Other objects include providing a method for manufacturing the thermal insulation material and the use of the thermal insulation material.

[0019] The solution of the present invention to achieve the above object is a thermal insulation material for electrochemical cells, preferably for lithium-ion batteries, for battery modules, and / or battery systems, which includes a thermal insulation layer, and the thermal insulation layer includes a first textile, where the first textile has a coating, and the coating contains aerogel particles and at least one binder, and at least part of the binder is water-soluble.

[0020] The solution of the present invention for achieving the above object is in particular a heat-insulating material for an electrochemical cell, preferably for a lithium-ion battery, which comprises a heat-insulating layer, and the heat-insulating layer comprises a first textile, wherein the first textile has a coating, the coating contains aerogel particles and at least one binder, wherein the binder is at least partially water-soluble, and wherein, as measured according to DIN EN ISO 9073-2:1997-02, the thickness of the first textile is in the range of 0.2 mm to 3.0 mm.

[0021] The heat-insulating material of the present invention is very suitable for heat insulation of electrochemical cells (preferably lithium-ion batteries), battery modules and / or battery systems, and shows high heat-insulating ability even with small thickness and weight. A battery module comprises at least two interconnected electrochemical cells, but does not include a battery management system. A battery system comprises at least one electrochemical cell and / or at least one battery module and a battery management system. The heat-insulating material meets the requirements for electrochemical cells regarding dynamic mechanical stability and heat-insulating ability under compression.

[0022] The heat-insulating material also has good recyclability. The achievement of good recyclability is based on the fact that since the binder is at least partially water-soluble, the heat-insulating material can be simply decomposed into its components by placing it in, for example, water or other suitable solvents. The aerogel particles have a low density. After the binder is dissolved, the aerogel particles float on the surface of the water and can be simply skimmed off, dried and reused.

[0023] Another advantage of the combination of aerogel and a binder that is at least partially water-soluble is that the aerogel has a large specific surface area. Thereby, a thinner binder layer can be achieved, which can be dissolved by water particularly quickly.

[0024] The binder is preferably at least partially water-soluble. According to the present invention, it can be determined whether the binder is at least partially water-soluble by means of the water-solubility measurement described in the measurement method section.

[0025] Wherein, based on the total weight of the coating, the proportion of the binder is preferably 3 wt% to 25 wt%, more preferably 3 wt% to 20 wt%, and particularly 5 wt% to 15 wt%.

[0026] The binder that is at least partially water-soluble may comprise a single at least partially water-soluble polymer or a mixture composed of at least partially water-soluble polymers.

[0027] Preferably, the at least partially water-soluble binder is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and their copolymers and mixtures.

[0028] Particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: polyvinyl acetate, partially saponified polyvinyl acetate, polyvinyl alcohol, polyacrylamide, cellulose-based binders (preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), and chemically modified starch (especially ethoxylated starch, hydroxypropylated starch), and their copolymers and mixtures.

[0029] Even more particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: polyvinyl acetate, partially saponified polyvinyl acetate, polyvinyl alcohol, polyacrylamide, cellulose-based binders (preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), and chemically modified starch (especially ethoxylated starch, hydroxypropylated starch), and their mixtures.

[0030] Even more particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulose-based binders (preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), and chemically modified starch (especially ethoxylated starch, hydroxypropylated starch), and their mixtures.

[0031] Even more particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 100 mol%, particularly 70 to 100 mol%, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch, hydroxypropylated starch, and their copolymers and mixtures.

[0032] More particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, particularly 70 to 95 mol%, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch, propoxylated starch, and copolymers and mixtures thereof.

[0033] More particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 100 mol%, particularly 70 to 100 mol%, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch and propoxylated starch, and mixtures thereof.

[0034] More particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, particularly 70 to 95 mol%, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch and propoxylated starch, and mixtures thereof.

[0035] More particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 100 mol%, particularly 70 to 100 mol%, polyvinyl alcohol, and copolymers and mixtures thereof.

[0036] More particularly preferably, the at least partially water-soluble binder is selected from the group consisting of: partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 100 mol%, particularly 70 to 100 mol%, polyvinyl alcohol, and mixtures thereof.

[0037] In another particularly preferred embodiment, the at least partially water-soluble binder is partially saponified polyvinyl acetate and / or polyvinyl alcohol preferably having a saponification degree of at least 50 mol%, such as 50 to 100 mol%, particularly 70 to 100 mol%.

[0038] In another particularly preferred embodiment, the at least partially water-soluble binder is partially saponified polyvinyl acetate preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, particularly 70 to 95 mol%.

[0039] The saponification degree of polyvinyl acetate can be determined with reference to IS K 6726 (94th edition, October 20, 2017).

[0040] Polyvinyl alcohol (PVOH) is a synthetic polymer that can be prepared by hydrolyzing or saponifying polyvinyl acetate. Among them, all acetate groups can be converted into alcohol groups, so that polyvinyl acetate can be completely hydrolyzed or saponified to prepare PVOH. Polyvinyl alcohol can be regarded as a homopolymer of vinyl alcohol. There are many hydrogen bonds in PVOH, which is a highly crystalline polymer and dissolves in hot water above about 60 °C.

[0041] However, incomplete hydrolysis of polyvinyl alcohol can also be achieved when a certain number of acetate groups remain. In this case, this leads to the formation of partially saponified polyvinyl acetate. Compared with polyvinyl alcohol, the number of hydrogen bonds in partially saponified polyvinyl acetate is less. The polymer has fewer hydrogen bonds, lower crystallinity, and is soluble in cold water. Therefore, partially saponified polyvinyl acetate can also be regarded as a vinyl alcohol-vinyl acetate copolymer. Preferred partially saponified polyvinyl acetates contain only vinyl alcohol groups and vinyl acetate groups.

[0042] The coating can include one or more polyvinyl alcohols, one or more partially saponified polyvinyl acetates, or a combination thereof that act as binders. In a preferred embodiment, the binder includes polyvinyl alcohol and / or partially saponified polyvinyl acetate.

[0043] In some embodiments, the binder includes a copolymer of polyvinyl alcohol and / or a copolymer of partially saponified polyvinyl acetate. In addition to vinyl alcohol groups, the polyvinyl alcohol copolymer contains at least another monomer unit. In addition to vinyl alcohol groups and vinyl acetate groups, the copolymer of partially saponified polyvinyl acetate contains at least another monomer unit.

[0044] In one embodiment, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate has at least another neutral monomer unit, especially ethylene, propylene, and / or N-vinylpyrrolidone.

[0045] In another embodiment, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate has at least another cationic monomer unit.

[0046] In another embodiment, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate has at least another anionic monomer unit, especially vinyl polymerization units, vinyl sulfonic acid monomers and their esters, vinyl monocarboxylic acid monomers and their esters and anhydrides, dicarboxylic acid monomers with polymerizable double bonds and their esters, anhydrides, and alkali metal salts of the above substances.

[0047] Examples of other anion monomer units that are particularly suitable are vinyl polymerization units corresponding to anionic vinyl monomers, including vinyl acetic acid, maleic acid, monoalkyl maleate, dialkyl maleate, maleic anhydride, fumaric acid, monoalkyl fumarate, dialkyl fumarate, itaconic acid, monoalkyl itaconate, dialkyl itaconate, citraconic acid, monoalkyl citraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid, monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate, glutaconic anhydride, alkyl acrylate, alkyl alkyl acrylate, vinyl sulfonic acid, sulfonic acid, allyl sulfonic acid, vinyl sulfonic acid, 2-acrylamide-1-methylpropanesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, 2-methylacrylamide-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali metal salts of the above substances (such as sodium salts, potassium salts or other alkali metal salts), esters of the above substances (such as methyl esters, ethyl esters or other C1-C4 or C6 alkyl esters), and combinations of the above substances (such as several types of anion monomers or equivalent forms of the same anion monomer).

[0048] In some embodiments, the copolymer of the polyvinyl alcohol copolymer and / or the partially saponified polyvinyl acetate may comprise two or more types of other monomer units selected from neutral, anionic and / or cationic monomer units.

[0049] The coating described herein may comprise one or several of the polymers acting as adhesives.

[0050] In a preferred embodiment, the coating has at least one non-white dye. The advantage of this solution is that the quality of the coating can be visually evaluated simply.

[0051] Further preferably, the first textile has glass fibers with a diameter of 1 to 30 μm, more preferably 5 to 20 μm, more preferably 7 to 18 μm, and particularly 7 to 15 μm.

[0052] The present invention further relates to a thermal insulation material for an electrochemical cell, preferably for a lithium-ion battery, for a battery module and / or a battery system, comprising a thermal insulation layer, the thermal insulation layer comprising a first textile, wherein the first textile has a coating, the coating comprising aerogel particles and an adhesive, wherein the adhesive is preferably at least partially water-soluble, and wherein the adhesive is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and copolymers and mixtures thereof, wherein, as measured according to DIN EN ISO 9073-2:1997-02, the thickness of the first textile is preferably in the range of 0.2 mm to 3.0 mm.

[0053] The preferred adhesive of the thermal insulation material corresponds to the description of the at least partially water-soluble adhesive described above.

[0054] Therefore, the adhesive is preferably selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and copolymers and mixtures thereof.

[0055] More preferably, the adhesive is preferably selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and copolymers and mixtures thereof.

[0056] Even more particularly preferably, the binder is selected from the group consisting of: polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulose-based binders (preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), and chemically modified starches (especially ethoxylated starch, hydroxypropylated starch), and mixtures thereof.

[0057] Even more particularly preferably, the binder is selected from the group consisting of: partially saponified polyvinyl acetate, preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, particularly 70 to 95 mol%, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch, hydroxypropylated starch, and mixtures thereof.

[0058] In another particularly preferred embodiment, the binder is partially saponified polyvinyl acetate, preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, particularly 70 to 95 mol%.

[0059] In a preferred embodiment of the present invention, based on the total weight of the coating, the coating comprises an amount of 3 wt% to 25 wt%, preferably 3 wt% to 20 wt%, particularly 5 wt% to 15 wt% of a binder that is at least partially water-soluble according to the method defined in the specification and / or a binder, which is preferably at least partially water-soluble and selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyvinylimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and copolymers and mixtures thereof.

[0060] In another preferred embodiment, the thermal insulation material of the present invention does not have a water-insoluble binder, or based on the total weight of the coating, only has an amount of water-insoluble binder less than 10 wt%, preferably less than 7.5 wt%, particularly less than 5 wt%. Among them, the water-insoluble binder is preferably a binder that is at least partially water-insoluble according to the method defined in the specification. The advantage of this solution is to improve the recyclability.

[0061] In another preferred embodiment, the heat-insulating material of the present invention does not have a water-insoluble binder, or has only an amount of water-insoluble binder less than 10 wt%, preferably less than 7.5 wt%, particularly less than 5 wt% based on the total weight of the coating, and the binder is selected from inorganic binding materials, particularly from binding materials containing water glass, silica sol, cement, clay minerals and / or phosphorus (for example in the form of phosphates).

[0062] In another preferred embodiment, the heat-insulating material of the present invention does not have an inorganic binder, or has only an amount of inorganic binder less than 1 wt%, preferably less than 0.5 wt%, particularly less than 0.1 wt% based on the total weight of the coating.

[0063] In another preferred embodiment, the heat-insulating material of the present invention does not have a blowing agent selected, for example, from saturated hydrocarbons containing 1 to 8 carbon atoms, halogenated hydrocarbons containing 1 to 8 carbon atoms and carbon dioxide, or has only an amount of blowing agent selected, for example, from saturated hydrocarbons containing 1 to 8 carbon atoms, halogenated hydrocarbons containing 1 to 8 carbon atoms and carbon dioxide less than 1 wt%, preferably less than 0.5 wt%, particularly less than 0.1 wt% based on the total weight of the coating.

[0064] In a preferred embodiment of the present invention, the coating does not have fibers not belonging to the textile, or has only an amount of fibers not belonging to the textile less than 5 wt%, further preferably less than 2.5 wt% based on the total weight of the coating. The advantage of this solution is that the thermal conductivity is reduced. In the uncompressed state of the heat-insulating material, the fibers not belonging to the textile do not come into contact with the textile.

[0065] Further preferably, the coating is made of a precursor material that does not contain fibers, or has only an amount of fibers less than 5 wt%, further preferably less than 2.5 wt% based on the total weight of the precursor material.

[0066] The aerogel particles preferably comprise an inorganic, organic or inorganic-organic hybrid material.

[0067] In principle, all metal oxides, polymers and some other substances can be used as the base materials for aerogel synthesis by means of the sol-gel process. Aerogels can be manufactured by drying a gel composed of a colloidal substance (preferably silica) under extreme conditions. Generalized aerogels, that is, "gels containing air as a dispersant", are manufactured by drying a suitable gel. Such an "aerogel" concept mainly includes aerogels in the narrow sense and xerogels. Among them, if the liquid of the gel is removed at a temperature higher than the critical temperature and starting from a pressure higher than the critical pressure, the dried gel is called an aerogel in the narrow sense. The advantage of this solution is that dimensional stability is ensured by these specific drying conditions.

[0068] If, on the other hand, the liquid of the gel is removed under subcritical conditions, for example in the case of forming a liquid-gas boundary phase, the resulting gel is called a xerogel. According to the present invention, aerogels that are not dried under critical conditions can also be used. In this treatment method, dimensional stability during the drying process (functionalized aerogels) is achieved through the functionalization of the aerogel precursor surface, preferably silanization. The advantage of functionalized aerogels is that they can be made hydrophobic through functionalization, thereby reducing the moisture absorbed during use. In addition, such aerogels can be continuously manufactured, so the cost is lower than that of aerogels in the narrow sense.

[0069] It should be noted that the aerogels of the present invention refer to gels containing air as a dispersant, that is, generalized aerogels. The shaping process of aerogels is usually completed during the sol-gel transition. After forming a solid gel structure, the shape can usually only be changed by crushing, such as grinding, because this material is too brittle for other processing forms.

[0070] Preferred aerogel particles are made of silica.

[0071] The aerogel particles preferably have a particle size distribution with a D50 value of 50 μm to 3 mm, more preferably 200 μm to 3 mm, and / or a D95 value of 50 μm to 10 mm, more preferably 500 μm to 5 mm and particularly 750 μm to 2.5 mm. In another preferred embodiment, the aerogel particles preferably have a particle size distribution with a D50 value of 5 μm to 300 μm, more preferably 5 μm to 150 μm, and / or a D95 value of 5 μm to 750 μm, more preferably 5 μm to 500 μm and particularly 5 μm to 500 μm. The particle size distribution is measured according to DIN 66165-2:2016-08.

[0072] Preferably, based on the total weight of the coating, the coating has an amount of aerogel particles of at least 60 wt%, such as 60 to 95 wt%, more preferably 60 to 90 wt%, more preferably 60 to 85 wt%, and particularly 60 to 80 wt%.

[0073] Also preferably, based on the total weight of the thermal insulation material, the thermal insulation material has an amount of aerogel particles of 6 to 75 wt%, more preferably 10 to 70 wt%, more preferably 10 to 60 wt%, more preferably 15 to 55 wt%.

[0074] According to the present invention, the thermal insulation material includes a first textile, and the first textile has a coating, and the coating includes aerogel particles and an adhesive. Among them, the coating is that the aerogel particles and the adhesive cover at least one surface of the first textile in at least a certain proportion. Among them, the coating can also at least partially penetrate into the first textile. Therefore, the coating can also exist in at least a partially impregnated form. The coating can be present on one or both surfaces of the first textile. Preferably, the coating is provided only on one surface, and the textile can provide mechanical protection on the side opposite to the coating and / or can be used as an adhesion aid.

[0075] In another preferred embodiment, the thermal insulation material has at least one second textile. The second textile can be used as a protective layer. In a preferred embodiment, the second textile is disposed on the side opposite to the coating and the first textile. In this way, the textile provides mechanical protection on both sides of the coating.

[0076] Among them, the coating can also at least partially penetrate into the second textile. Therefore, the coating can also exist in at least a partially impregnated form in the second textile. This achieves the advantage of further improved particle embedding because the particles can "wedge" into the fiber gaps.

[0077] Also preferably, at least a part of the second textile is located outside the coating. This can protect the thermal insulation material from mechanical loads.

[0078] If the thermal insulation material does not have other textiles except the first textile, then based on the total weight of the thermal insulation material, the proportion of aerogel particles is preferably up to 75 wt%, such as 10 to 75 wt%, more preferably 10 to 65 wt%, more preferably 15 to 65 wt%, more preferably 15 to 55 wt%.

[0079] If the thermal insulation material further has a second fabric and / or other fabrics in addition to the first fabric, the proportion of the aerogel particles is preferably at least 6 wt%, for example 6 to 60 wt%, more preferably 10 to 60 wt%, more preferably 10 to 55 wt%, and more preferably 15 to 45 wt%, based on the total weight of the thermal insulation material.

[0080] In addition, the coating may comprise one or several additional additives, such as fire retardant additives, in particular additives based on organic nitrogen compounds and / or phosphorus compounds. These additives are particularly advantageous because in addition to the flame retardant effect, they also have a plasticizing and softening effect on the polymer.

[0081] The coating may also comprise wetting agents, for example for achieving an aqueous coating formulation comprising incompatible hydrophobic aerogels, and rheological modifying additives, such as acrylates, acrylamides, cellulose systems, dispersion aids, dyes and / or defoamers.

[0082] In a preferred embodiment of the invention, the first and / or second fabric is a nonwoven fabric. The nonwoven fabric refers to a structure formed by fibers of limited length (staple fibers), continuous fibers (filaments) or cut yarns of any kind and any origin, which are joined together in any manner to form a fiber web (fiber layer, fiber fleece) and are connected together in any manner; wherein it does not include the yarn interlacing or entanglement occurring in the manufacture of woven, knitted, braided, lace-making, woven and tufted products. Films and papers do not belong to nonwoven fabrics. Nonwoven fabrics are defined in the DIN 61210-2:1988-10 standard.

[0083] Preferably, the first and / or second fabric is a wet-laid nonwoven fabric. The advantage of this solution is that the wet-laid nonwoven fabric has isotropy and uniformity. In another preferred embodiment, the first and / or second fabric is a nonwoven fabric composed of fibers with a fiber length of 0.5 to 20 mm, more preferably 2 to 20 mm, more preferably 5 to 20 mm, more preferably 5 to 18 mm, particularly 8 to 15 mm, particularly a wet-laid nonwoven fabric. Preferably, based on the total amount of fibers in the fabric, the first and / or second fabric is a nonwoven fabric comprising at least 50 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt% and particularly 100 wt% of fibers with a fiber length of 0.5 to 20 mm, more preferably 2 to 20 mm, more preferably 5 to 20 mm, more preferably 5 to 18 mm, especially 8 to 15 mm, particularly a wet-laid nonwoven fabric.

[0084] The advantages of short fibers are that they are not easily entangled with each other and are more easily recyclable. The diameter of the fibers is preferably 1 to 30 μm, more preferably 5 to 20 μm, still more preferably 7 to 18 μm, and particularly 7 to 15 μm.

[0085] Equally preferably, the first and / or second textile fabric is a non-woven fabric bonded to an adhesive material, in particular to an adhesive material that is at least partially water-soluble, in particular a wet-laid non-woven fabric. Among them, the water solubility of the adhesive material can be determined in a similar manner as the method for adhesives described in the measurement method section. Preferably, the adhesive material, in particular the at least partially water-soluble adhesive material, is selected from the polymers described in the present invention for the at least partially water-soluble adhesives.

[0086] In one embodiment, the adhesive material is preferably at least partially water-soluble and is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide and their copolymers, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and mixtures thereof.

[0087] In another embodiment, the adhesive material is preferably at least partially water-soluble and is selected from the group consisting of: polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulose-based adhesives (preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), and chemically modified starch (especially ethoxylated starch, hydroxypropylated starch), and mixtures thereof.

[0088] In another embodiment, the adhesive material is preferably at least partially water-soluble and is selected from the group consisting of: polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulose-based adhesives (preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), and chemically modified starch (especially ethoxylated starch, hydroxypropylated starch), and mixtures thereof.

[0089] In another embodiment, the adhesive material is preferably at least partially water-soluble and is selected from the group consisting of: partially saponified polyvinyl acetate, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch, and hydroxypropylated starch, preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, particularly 70 to 95 mol%, and mixtures thereof.

[0090] In another preferred embodiment, the first and / or second textile contains glass fibers. Preferably, both the first textile and the second textile contain glass fibers. The advantage of using glass fibers is that they have a high density and sink during the recycling process, so they are easy to separate from the lighter aerogel particles. Preferably, based on the total weight of the thermal insulation material, the proportion of the glass fibers is 25 to 94 wt%, more preferably 35 to 85 wt%, further preferably 40 to 75 wt%, and particularly 50 to 65 wt%. Further preferably, based on the total weight of the first textile, the proportion of the glass fibers in the first textile is 60 to 98 wt%, more preferably 70 to 95 wt%, and particularly 80 to 95 wt%. Further preferably, based on the total weight of the second textile, the proportion of the glass fibers in the second textile is 60 to 98 wt%, more preferably 70 to 95 wt%, and particularly 80 to 95 wt%.

[0091] The glass fibers are preferably short fibers, and their average fiber length is preferably 2 to 20 mm, more preferably 5 to 18 mm, and particularly 8 to 15 mm. The diameter of the glass fibers is preferably 1 to 30 μm, more preferably 5 to 20 μm, and particularly 7 to 15 μm. Among them, the above-mentioned glass fibers can be used independently for the first and / or second textile.

[0092] In a preferred embodiment of the present invention, the first textile is a non-woven fabric, preferably a wet-laid non-woven fabric. In another preferred embodiment of the present invention, the second textile is a non-woven fabric, preferably a wet-laid non-woven fabric.

[0093] The first and second textiles can also independently have non-glass fibers, especially adhesive fibers and / or at least partially water-soluble fibers. Preferred adhesive fibers and / or at least partially water-soluble fibers are polyvinyl alcohol fibers and / or polyvinyl acetate fibers, where the polyvinyl acetate is saponified, and the saponification degree is preferably at least 50 mol%, such as 50 to 100 mol%, particularly 70 to 100 mol%. The measurement for determining whether a fiber is at least partially water-soluble is described in the measurement method section.

[0094] If present, the proportion of fibers other than glass fibers, in particular fibers that are at least partially water-soluble, in the first textile is 40 to 2 wt%, further preferably 30 to 4 wt%, further preferably 25 to 5 wt%, and in particular 15 to 5 wt%, based on the total weight of the first textile. If present, the proportion of fibers other than glass fibers, in particular fibers that are at least partially water-soluble, in the second textile is 40 to 2 wt%, further preferably 30 to 4 wt%, further preferably 25 to 5 wt%, and in particular 15 to 5 wt%, based on the total weight of the second textile.

[0095] In one embodiment, the first and second textiles independently of each other comprise a combination of glass fibers and fibers other than glass fibers.

[0096] The fibers that are at least partially water-soluble may comprise a single at least partially water-soluble polymer or a mixture composed of at least partially water-soluble polymers. Preferred fibers other than glass fibers are fibers comprising at least one polymer as described for the at least partially water-soluble binder.

[0097] Preferably, as measured according to ISO 9073-1:1989-07, the areal weight of the first textile is in the range of 30 g / m 2 to 300 g / m 2 and further preferably in the range of 40 g / m 2 to 300 g / m 2 and in particular in the range of 50 g / m 2 to 250 g / m 2 The advantage of this solution is that the first textile has a coverage sufficient to ensure good fiber-coating interaction and also has sufficient strength for further processing.

[0098] Equally preferably, as measured according to DIN EN ISO 9073-2:1997-02, the thickness of the first textile is in the range of 0.2 mm to 3.0 mm, further preferably in the range of 0.3 mm to 2.5 mm, and in particular in the range of 0.5 mm to 2.0 mm. The advantage of a textile with a small thickness is low space requirements. In addition, the thermal insulation material can contain a relatively large amount of aerogel while the total thickness is still small.

[0099] The advantage of a textile with a larger thickness is compressibility, higher strength, and the ability to compensate for thickness fluctuations of the battery cell.

[0100] In another preferred embodiment of the present invention, the coating is a coating applied to the first textile with a (preferably aqueous) dispersion. Preferably, the dispersion has a solids content in the range of 10 to 30 wt%, more preferably 15 to 25 wt%. The advantage of this solution is that a large amount of solids can be applied under low viscosity conditions with a relatively small amount of liquid phase.

[0101] In one embodiment, the coating is made with a (preferably aqueous) dispersion that does not contain fibers, or contains fibers in a proportion of less than 2 wt%, more preferably less than 1 wt%, and particularly less than 0.5 wt% based on the total weight of the dispersion.

[0102] Preferably, the areal weight of the second textile is in the range of 30 g / m 2 to 300 g / m 2 range, more preferably in the range of 40 g / m 2 to 300 g / m 2 range, particularly in the range of 50 g / m 2 to 250 g / m 2 range. The advantage of this solution is that the textile has a coverage sufficient to ensure good fiber-coating interaction and also has sufficient strength for further processing.

[0103] Also preferably, as measured according to DIN EN ISO 9073-2:1997-02, the thickness of the second textile is in the range of 0.2 mm to 3.0 mm, preferably in the range of 0.3 mm to 2.5 mm, and particularly in the range of 0.5 mm to 2.0 mm. The advantage of a textile with a small thickness is low space requirements. The advantage of a textile with a larger thickness is compressibility and the ability to compensate for thickness fluctuations of the battery cell.

[0104] As measured according to DIN EN ISO 9073-18:2008-08, the second textile has a relatively small maximum tensile force, so that the protected thermal insulation material has flexibility. Preferably, the maximum tensile force of the second textile is in the range of 5 to 80 N / 5 cm, preferably in the range of 10 to 70 N / 5 cm, and particularly preferably in the range of 15 to 60 N / 5 cm.

[0105] In another preferred embodiment of the present invention, as measured according to DIN EN ISO 9073-18:2008-08, the second textile has a tensile force of 2 to 60 N / 5 cm at 1% elongation, which is preferably in the range of 3 to 50 N / 5 cm, more preferably in the range of 5 to 45 N / 5 cm, still more preferably in the range of 10 to 45 N / 5 cm, and particularly in the range of 10 to 30 N / 5 cm. The advantage of this solution is that the strength at low elongation is low, so that the material maintains a certain flexibility.

[0106] As measured according to DIN EN ISO 9073-18:2008-08, the first textile has a maximum tensile force of at least 30 N / 5 cm, which is preferably in the range of 30 to 1000 N / 5 cm, more preferably 30 to 800 N / 5 cm, still more preferably 30 to 400 N / 5 cm, still more preferably 30 to 200 N / 5 cm, and particularly 30 to 100 N / 5 cm. The advantage of the minimum tensile force is that it imparts sufficient strength to the thermal insulation material for handling.

[0107] In another embodiment of the present invention, the thermal insulation material and / or the coating do not have a water-insoluble binder, or have only an amount of water-insoluble binder of less than 10 wt%, preferably less than 7.5 wt%, particularly less than 5 wt% based on the total weight of the coating, wherein the water-insoluble binder is preferably a water-insoluble binder according to the method defined in the specification.

[0108] Further preferably, the coating is made of a precursor material that does not contain a water-insoluble binder, or contains only an amount of water-insoluble binder of less than 10 wt%, preferably less than 7.5 wt%, particularly less than 5 wt% based on the total weight of the precursor material, wherein the water-insoluble binder is preferably a water-insoluble binder according to the method defined in the specification.

[0109] In another embodiment of the present invention, the thermal insulation material has a flame-retardant layer, which preferably comprises a layered silicate, particularly mica. Preferably, as measured according to ISO 9073-1:1989-07, the flame-retardant layer has at least 50 g / m 2 , preferably 60 to 500 g / m 2 , more preferably 60 to 300 g / m 2 , and particularly 70 to 150 g / m 2 of weight. Particularly preferably, the flame-retardant layer is disposed in the thermal insulation material in such a way as to serve as at least one outer surface of the thermal insulation material.

[0110] In another embodiment of the present invention, the thermal insulation material has an infrared reflective layer. Among them, the infrared reflective layer is preferably arranged in the thermal insulation material in such a way as to serve as at least one outer surface of the thermal insulation material.

[0111] In another preferred embodiment, as measured according to DIN EN ISO 9237:1995-12 under the condition of 100 Pa, the coating and / or the thermal insulation material has at least 50 L / m 2 s, for example 100 L / m 2 s to 600 L / m 2 s, preferably 200 L / m 2 s to 500 L / m 2 s, and particularly 300 L / m 2 s to 400 L / m 2 s of air permeability (delta p). Further preferably, as measured according to DIN EN ISO 9237:1995-12 under the condition of 200 Pa, the coating and / or the thermal insulation material has at least 100 L / m 2 s, for example 300 L / m 2 s to 900 L / m 2 s, preferably 400 L / m 2 s to 800 L / m 2 s, and particularly 500 L / m 2 s to 700 L / m 2 s of air permeability (delta p).

[0112] The advantage of the air permeability is that the thermal insulation material can be cooled by air convection thereby. The cooling is particularly efficient when the thermal insulation material has not been compressed due to the operation of the electrochemical cell.

[0113] In another preferred embodiment, as measured according to DIN EN ISO 9073-2:1997-02, the thickness of the coating and / or the thermal insulation material is in the range of 1 mm to 9 mm or 0.6 mm to 9 mm, preferably in the range of 1.2 mm to 6 mm or 0.6 mm to 6 mm, further preferably in the range of 1.3 mm to 4 mm or 0.6 mm to 4 mm, particularly in the range of 1.3 mm to 3 mm or 0.6 mm to 3 mm. If the thickness is less than 4 mm, and particularly less than 3 mm, the space requirement is particularly low.

[0114] In another preferred embodiment, the mass per unit area of the thermal insulation material is in the range of 60 g / m 2 to 900 g / m 2 range, preferably in the range of 70 g / m 2 to 600 g / m 2Preferably further within the range of 80 g / m 2 to 400 g / m 2 Preferably further within the range of 80 to 200 g / m 2 . The low weight is beneficial for applications in electrochemical cells.

[0115] Preferably further, as measured according to the description in the measurement method section, the thermal insulation layer material has recyclability characteristics with a rating of 1, 2, or 3.

[0116] Preferably further, as measured according to ASTM D 5470-17, the thermal conductivity of the thermal insulation material under a pressure load of 20 kPa is from 0.045 to 0.010 W / m·K, more preferably from 0.040 to 0.010 W / m·K, particularly from 0.036 to 0.010 W / m·K. Preferably further, as measured according to ASTM D 5470-17, the thermal conductivity of the thermal insulation material under a pressure load of 2059 kPa is from 0.035 to 0.010 W / m·K, more preferably from 0.030 to 0.010 W / m·K, particularly from 0.027 to 0.010 W / m·K.

[0117] In a particularly preferred embodiment, the thermal insulation material is a thermal insulation material for an electrochemical cell, preferably for a lithium-ion battery, which comprises a thermal insulation layer, and the thermal insulation layer comprises a first fabric, wherein the first fabric has a coating, and the coating contains aerogel particles and at least one binder selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide and their copolymers, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and their copolymers and mixtures, wherein, as measured according to DIN EN ISO 9073-2:1997-02, the thickness of the first fabric is preferably in the range of 0.2 mm to 3.0 mm.

[0118] Preferred embodiments of the thermal insulation material are the embodiments described above and below. Accordingly, the binder is preferably at least partially soluble in water. In addition, the first textile is preferably a wet-laid nonwoven. Also preferably, the first textile is a nonwoven, preferably a wet-laid nonwoven, which is bonded to a bonding material selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymers, polyvinyl pyrrolidone, polyethylene imine, polyalkylene oxides, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acids and their salts, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides and their copolymers, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and mixtures thereof.

[0119] The invention further relates to an electrochemical cell, preferably a lithium-ion cell, which is thermally insulated by at least one thermal insulation material according to the invention.

[0120] The invention furthermore relates to a battery system in which at least one electrochemical cell, preferably at least one lithium-ion cell, is thermally insulated by at least one thermal insulation material according to the invention.

[0121] The present invention furthermore relates to a battery module and / or a battery system in which at least two electrochemical cells are thermally insulated from one another by at least one thermal insulation material according to the present invention.

[0122] The present invention also relates to a method for recycling the thermal insulation material of the present invention, which comprises the following steps:

[0123] a1) pulverizing the heat insulating material of the present invention and placing it in a solvent, preferably water,

[0124] a2) the thermal insulation material is stirred and heated as appropriate,

[0125] a3) separating the aerogel particles and the fibers of the textile from each other.

[0126] Preferably, a solvent that at least partially dissolves the binder is used as the solvent. Preferably, the solvent is water.

[0127] Preferably, one or more of the thermal insulation materials in the embodiments are recycled by means of the recycling method. Therefore, preferred embodiments of the thermal insulation material recycled by the method include the embodiments described above and below.

[0128] The present invention also relates to a method for producing a thermal insulation material for an electrochemical cell, comprising the following steps:

[0129] 1. Provide a first textile fabric, which, as measured according to DIN EN ISO 9073-2:1997-02, preferably has a thickness in the range of 0.2 mm to 3.0 mm.

[0130] 2. Coat the textile fabric with a dispersion comprising aerogel particles and a binder, wherein

[0131] a) according to the method defined in the specification, the binder is at least partially water-soluble, and / or,

[0132] b) according to the method defined in the specification, the binder is preferably at least partially water-soluble, and wherein the binder is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide and its copolymer, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and their copolymers and mixtures;

[0133] 3. Dry the resulting coating to form a heat-insulating layer.

[0134] The present invention also relates to a method for manufacturing a heat-insulating material for an electrochemical cell, which comprises the following steps:

[0135] 1. Provide a first textile fabric, which, as measured according to DIN EN ISO 9073-2:1997-02, preferably has a thickness in the range of 0.2 mm to 3.0 mm.

[0136] 2. Coat the textile fabric with a dispersion comprising aerogel particles and a binder, wherein the binder is at least partially water-soluble according to the method defined in the specification.

[0137] 3. Dry the resulting coating to form a heat-insulating layer.

[0138] Preferred embodiments of the present invention include making necessary modifications to the preferred embodiments of the heat-insulating material of the present invention. Therefore, preferably, one or more heat-insulating materials in the above-described embodiments are manufactured by means of the method of the present invention.

[0139] Accordingly, in a preferred embodiment, in step 2a following step 2, at least one second textile fabric that can be used as a protective layer is provided for the heat-insulating layer. In this case, preferably, the second textile fabric is disposed on the side of the first textile fabric having the coating.

[0140] The dispersion may further comprise a wetting agent, such as for achieving an aqueous coating formulation containing incompatible hydrophobic aerogels and rheology modifying additives, such as acrylates, acrylamides, cellulose systems, dispersion aids, dyes, and / or defoamers.

[0141] Further preferably, in step 2, the fabric is coated in the form of a knife coating.

[0142] The present invention also relates to the use of the thermal insulation material for thermal management and / or thermal insulation of electrochemical cells, preferably for lithium-ion batteries, battery modules, and / or battery systems.

[0143] Preferred embodiments of the use of the present invention include preferred embodiments of the thermal insulation material of the present invention (with necessary modifications).

[0144] Measurement method

[0145] Measurement of the water solubility of the binder:

[0146] Add 300 g of distilled water to a 500 mL conical flask. Add 0.5 g of dry binder, preferably having a particle size with a D90 value of 100 μm (measured according to DIN 66165-2:2016-08). Place the flask in a laboratory shaker and keep it at 80 °C for 24 h. It should be noted here that the shaking frequency is selected to make the mixture move and replenish the evaporated water. After 24 h, the solid phase (if any) is quantitatively separated, preferably by filtration. The aqueous phase is concentrated to dryness. If no residue is obtained, or the amount of the residue is less than 50 mg, then the binder is insoluble in water. If a residue with an amount of at least 50 mg is obtained, then the binder is at least partially soluble in water.

[0147] Measurement of the water solubility of the fiber:

[0148] Add 300 g of distilled water to a 500 mL conical flask. Subsequently, add 0.5 g of fiber. Place the flask in a laboratory shaker and keep it at 80 °C for 24 h. It should be noted here that the shaking frequency is selected to make the mixture move and replenish the evaporated water. After 24 h, the possible solid phase is quantitatively separated, preferably by filtration. The aqueous phase is concentrated to dryness. If no residue is obtained, or the amount of the residue is less than 50 mg, then the fiber is insoluble in water. If a residue with an amount of 50 mg or more is obtained, then the fiber is at least partially soluble in water.

[0149] Determination of the recyclability characteristics:

[0150] Take a sample (Sample 1) of the material to be tested in the size of DIN A4 (German Industrial Standard), and cut it into small pieces (about 2x2 cm). Put the sample into a 2000 mL beaker, and add 1000 mL of water to the sample. Stir vigorously, heat the water to boiling and then stir for 60 min. Subsequently, cool it to room temperature (23 °C) while stirring, and then perform phase separation for 60 min. After the separation is completed, skim off the aerogel particle slurry, and repeat this process twice. Then transfer the aerogel particle slurry into a crystallizing dish, dry it at 120 °C for 6 h until constant weight, and measure the mass. If the difference between the mass of the original aerogel particles in the sample and the mass measured in the test is less than 25%, the recyclability characteristic of this thermal insulation material is rated 1 point. If the difference between the mass of the original aerogel particles in the sample and the mass measured in the test is 25% to 35%, the recyclability characteristic of this thermal insulation material is rated 2 points. If the difference between the mass of the original aerogel particles in the sample and the mass measured in the test is 35% to 45%, the recyclability characteristic of this thermal insulation material is rated 3 points. If the difference between the mass of the original aerogel particles in the sample and the mass measured in the test is higher than 45%, the recyclability characteristic of this thermal insulation material is rated 4 points.

[0151] The present invention will be described in detail below in conjunction with non-limiting examples.

[0152] Manufacture Sample I:

[0153] Add 60 g of a 5% solution composed of distilled water and partially saponified polyvinyl acetate (Poval 5-74, Kuraray Co., saponification degree 74%) to a 1000 mL beaker, and mix it with 0.2 g of an ethoxylated fatty alcohol-based wetting agent (Rucogen D3, Rudolf Chemie Co.). While stirring vigorously with a KPG stirrer, add 12 g of SiO2 aerogel particles in portions, the particle size of which is 0.1–0.5 mm and its surface is hydrophobic (Enova IC 3105, Cabot Co.). After adding all the particles, use a spatula to coat, and apply the obtained slurry to a wet-laid glass fiber mat with a unit area weight of 60 g / m 2 and dry it. The binder of the glass fiber mat is the same as the binder for the aerogel particles.

[0154] Manufacture Sample II:

[0155] Manufacture Sample II in a manner similar to Sample I. After coating, cover another layer of glass fiber mat on the still wet layer, gently press it and then dry it.

[0156] Reference Sample 1:

[0157] Aerogel felt: Model: SACB-0-6

[0158] Company: Tradematt(Henan)Industry Co., Ltd.

[0159] Shenglong Square

[0160] Zhengdong New Area

[0161] Zhengzhou

[0162] China

[0163] Reference Sample 2:

[0164] Nasbis heat shield: EYGY0912QN3P (film on the product removed).

[0165] Company: Panasonic Industrial Devices

[0166] Two Riverfront Plaza

[0167] Newark, NJ 07102-5490

[0168] USA

[0169] Characteristics:

[0170] Structure <![CDATA[Weight (g / m 2 )]]> Thickness (mm) Sample 1 Single layer, with coating 170 2.0 Sample 2 Interlayer structure 225 2.2 Reference sample 1 Single layer 1315 6.3 Reference sample 2 Single layer 190 0.96

[0171] Dynamic mechanical load test:

[0172] First, punch out 3 circular specimens with a diameter of 25 mm, weigh them, and place them between 2 pressure plates. Then apply a cyclic compressive load with the following parameters:

[0173] Climatic conditions: 23 °C, 50% relative air humidity

[0174] Pressure load: between the pressure plates

[0175] Static pressure: 0.85 MPa

[0176] Dynamic pressure (oscillation): + / -0.65 Mpa

[0177] Frequency: 1 Hz

[0178] Number of cycles: 300

[0179] Subsequently, remove the loaded samples from the test device, weigh them, and conduct a visual assessment. The visual assessment is carried out as follows: Shake the samples on a white paper (for colored particles) or a black paper (for white particles) and evaluate whether the particles separate from the coating. For laminates, the laminate adhesion is also evaluated.

[0180] Evaluation:

[0181]

[0182] Conclusion:

[0183] After being subjected to the dynamic load, the three measurement results of Sample I did not show the decomposition phenomenon of aerogel particle detachment. For the layer additionally protected by another non-woven fabric (three measurements of Sample II), the thermal insulation material did not show delamination or aerogel particle detachment.

[0184] The reference sample 1 showed aerogel dust during the specimen installation process, and more significantly detached aerogel particles on the test plate and during the shaking test after the load. The reference sample 2 detached aerogel particles during the shaking test.

[0185] Thermal conductivity measurement

[0186] According to ASTM D 5470-17, the thermal conductivity was measured under a pressure load, and the results are as follows:

[0187]

[0188] Conclusion:

[0189] Samples 1 and 2 manufactured according to the present invention provide a lower thermal conductivity throughout the pressure range, and their thermal insulation properties are better.

[0190] Recyclability

[0191] The recyclability of Sample 1 was determined by the above method and scored 1 point. The reference sample 1 was scored 4 points.

Claims

1. A thermal insulation material for an electrochemical cell, preferably for a lithium-ion battery, comprising a thermal insulation layer, said thermal insulation layer comprising a first textile, wherein said first textile has a coating, said coating comprising aerogel particles and at least one binder, wherein according to the method defined in the specification, said binder is at least partially water-soluble, characterized in that, Measured according to DIN EN ISO 9073-2:1997-02, the thickness of the first textile is in the range of 0.2 mm to 3.0 mm.

2. A thermal insulation material for an electrochemical cell, preferably for a lithium-ion battery, comprising a thermal insulation layer, said thermal insulation layer comprising a first textile, wherein said first textile has a coating, said coating comprising aerogel particles and at least one binder, characterized in that, The adhesive is preferably at least partially water-soluble and is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acids and their salts, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides and their copolymers, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and their copolymers and mixtures, wherein, measured according to DIN EN ISO 9073-2:1997-02, the thickness of the first textile is preferably in the range of 0.2 mm to 3.0 mm.

3. The heat-insulating material according to claim 1 or 2, characterized in that, The adhesive is selected from the group consisting of: partially saponified polyvinyl acetate, preferably having a saponification degree of at least 50 mol%, such as 50 to 100 mol%, preferably 70 to 100 mol% (according to IS K6726, 94th edition, October 20, 2017), polyvinyl alcohol, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethoxylated starch and hydroxypropylated starch, and their copolymers and mixtures.

4. The heat insulation material according to any one or more of the above-mentioned claims, characterized in that, The adhesive is selected from the group consisting of: partially saponified polyvinyl acetate, preferably having a saponification degree of at least 50 mol%, such as 50 to 95 mol%, preferably 70 to 95 mol% (according to IS K 6726, 94th edition, October 20, 2017), and its copolymers and mixtures.

5. The heat-insulating material according to any one or more of the above claims, characterized in that, The coating at least partially penetrates into the first textile.

6. The heat-insulating material according to any one or more of the above claims, characterized in that, The thermal insulation material has at least one second textile, and the second textile is disposed on the side of the coating opposite to the first textile.

7. The heat-insulating material according to any one or more of the above claims, characterized in that, The coating at least partially penetrates into the second textile.

8. The heat-insulating material according to any one or more of the above claims, characterized in that, At least a part of the second textile is located outside the coating.

9. The heat-insulating material according to any one or more of the above claims, characterized in that, Measured according to DIN 66165-2:2016-08, the aerogel particles have a particle size distribution with a D50 value of 50 μm to 3 mm.

10. The heat-insulating material according to any one or more of the above claims, characterized in that, Based on the total weight of the coating, the coating has an aerogel particle content of at least 60 wt%, such as 60 to 95 wt%, and / or based on the total weight of the thermal insulation material, the thermal insulation material has an aerogel particle content of 6 to 75 wt%.

11. The heat-insulating material according to any one or more of the above claims, characterized in that, The first and / or second textile is a non-woven fabric, and the non-woven fabric is preferably bonded to an adhesive material, and the adhesive is at least partially water-soluble according to the method defined in the specification.

12. The heat-insulating material according to any one or more of the above claims, characterized in that, The first textile is a non-woven fabric, preferably a wet-laid non-woven fabric, which is bonded to an adhesive material. The adhesive is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide and their copolymers, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and mixtures thereof.

13. The heat-insulating material according to any one or more of the above claims, characterized in that, The first and / or second textile is a wet-laid non-woven fabric, which is preferably bonded to an adhesive material. The adhesive is at least partially water-soluble according to the method defined in the specification.

14. The heat insulation material according to any one or more of the above claims, characterized in that, The first and / or second textile contains glass fibers with an average fiber length preferably ranging from 2 to 20 mm.

15. The heat-insulating material according to any one or more of the above claims, characterized in that, As measured according to DIN EN ISO9073-2:1997-02, the thickness of the first and / or second textile ranges from 0.2 mm to 3.0 mm, preferably from 0.3 mm to 2.5 mm, and particularly from 0.5 mm to 2.0 mm.

16. The heat-insulating material according to any one or more of the above claims, characterized in that, The thermal insulation material does not contain a water-insoluble adhesive, or contains only less than 10 wt%, preferably less than 7.5 wt%, and particularly less than 5 wt% of a water-insoluble adhesive based on the total weight of the coating, where the water-insoluble adhesive is preferably an adhesive that is at least partially water-insoluble according to the method defined in the specification.

17. An electrochemical cell, preferably a lithium-ion battery, which is thermally insulated by at least one thermal insulation material as described in any one or more of the above claims, and / or a battery system, in which at least one electrochemical cell, preferably at least one lithium-ion battery, is thermally insulated by at least one thermal insulation material as described in any one or more of the above claims.

18. A battery module and / or a battery system, in which at least two electrochemical cells are thermally insulated from each other by at least one thermal insulation material as described in any one or more of the above claims.

19. A method for manufacturing a thermal insulation material for an electrochemical cell, which comprises the following steps: a) Providing a first textile, the thickness of which preferably ranges from 0.2 mm to 3.0 mm as measured according to DIN EN ISO 9073-2:1997-02, b) Coating the textile with a dispersion containing aerogel particles and an adhesive, where b1) The adhesive is at least partially water-soluble according to the method defined in the specification, and / or, b2) The binder is preferably at least partially water-soluble according to the method defined in the description, and wherein, The binder is selected from the group consisting of: polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxide, polyacrylamide, polyacrylic acid and its salts, polycarboxylic acid and its salts, polyamino acid, modified starch, ethoxylated starch, hydroxypropylated starch, modified cellulose such as cellulose ether, cellulose ester, cellulose amide and their copolymers, pullulan, guar gum, gum arabic, xanthan gum, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and their copolymers and mixtures; c) Drying the obtained coating to form a heat-insulating layer.

20. A method for recycling the heat-insulating material according to any one or more of claims 1 to 16, comprising the following steps: a1) Crushing the heat-insulating material and placing it in a solvent preferably water, a2) Stirring the heat-insulating material and heating it if necessary, a3) Separating the aerogel particles from the fibers of the fabric from each other.

21. Use of the heat-insulating material according to any one or more of claims 1 to 16 for thermal management and / or heat insulation of an electrochemical cell, a battery module and / or a battery system preferably a lithium-ion battery.

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