Thermal insulation materials for electrochemical cells

Abstract

The present invention relates to an insulating material for electrochemical cells, advantageously lithium-ion cells, comprising an insulating layer comprising a first textile sheet, the first textile sheet having a coating containing aerogel particles and at least one binder, the binder being at least partially water-soluble.

Description

[Technical Field]

[0001] The present invention relates to an insulating material for electrochemical cells, in particular lithium-ion cells, to electrochemical cells, preferably lithium-ion cells, which are thermally insulated by the insulating material according to the present invention, as well as to cell modules and / or battery systems in which at least two electrochemical cells are thermally insulated from one another by the insulating material according to the present invention. The present invention also relates to a method for producing the insulating material and its use.

[0002] Thermal insulation materials are known to prevent or at least delay "thermal runaway" in electrochemical cells. Thermal runaway represents a high safety risk. For this reason, safety standards for lithium-ion batteries also include fire tests. In these tests, cells within a battery module are subjected to "thermal runaway" to determine whether a fire occurs as a result of heat propagation to other cells. To mitigate this risk, fire-resistant or insulating materials, i.e., materials with high thermal insulating properties, are usually placed between the cells.

[0003] Conventional insulating materials, such as foam or fiberboard, can withstand high temperatures but have relatively low insulating capacity. Therefore, such materials require high insulation thickness to ensure effective thermal management. However, the space required for a battery module limits the space available for insulation between cells within the module. Refractory materials, such as mica or ceramic board, can also withstand high temperatures but are relatively incompressible and have low insulating capacity. Therefore, such materials are not suitable for battery systems in which cells expand and contract during operation, such as pouch cells and prismatic cells.

[0004] It is also desirable to limit the total weight of the battery module without compromising its resistance to heat and fire spread, and mechanical properties.

[0005] Furthermore, it is known to use aerogels, which have very high insulating properties, to achieve good thermal insulation. Aerogels are a type of structure with low density, an open-cell structure, a large surface area, and pore sizes in the nanometer range. Their mechanism of action is based on the fact that their low density allows heat conduction over long distances within the skeletal structure. Furthermore, the large pore volume and very small pore diameter minimize convection. To enhance their insulating properties, aerogels can be mixed with dopants that absorb or scatter infrared radiation. Typically, aerogel materials have thermal resistance two to six times greater than other common insulating materials, such as foams and fiberglass. This allows aerogels to enhance effective shielding and thermal insulation without significantly increasing the thickness or weight of the insulating material.

[0006] It would be desirable to have an insulating material for the thermal management of electrochemical cells, in particular lithium-ion batteries, that is suitable for the thermal insulation of individual cells, cell modules and / or battery systems and that combines high insulating capacity with low thickness and weight. Furthermore, from a sustainability perspective, it would be desirable for the insulating material to be easily recyclable.

[0007] Open-cell foams filled with aerogel particles are known from U.S. Patent Application Publication No. 2012 / 0142802. U.S. Patent Application Publication No. 2019 / 0161909, named by Oikawa, discloses a heat shield plate using a nonwoven fabric and aerogel. However, the material described therein does not possess the desired combination of thermal properties, fire resistance, mechanical properties, and hydrophobicity for use in a battery thermal management element. Furthermore, the material is not easily recyclable.

[0008] WO 2021142169 discloses a battery thermal management element comprising a first thermal protection layer and at least one elastic layer containing one or more organic materials. The thermal protection layer may contain an aerogel composition, preferably a silica-aerogel composition. The aerogel composition may further contain a binder, which may include adhesives, resins, cements, foams, and polymers. The thermal management element is not easily recyclable.

[0009] From US2021257690 A1 an assembly for a battery is known, which comprises a thermal management multilayer film arranged on the surface of an electrochemical cell, the thermal management multilayer film comprising: a thermal insulating layer; a first heat dissipation layer disposed on the first surface of the thermal insulation layer; a second heat dissipation layer disposed on the second surface of the thermal insulation layer; Includes.

[0010] The thermal insulation layer can contain, for example, a nonwoven fiberglass fabric combined with aerogel and a binder. Binders for the fiberglass layer include epoxides, polyamides, polyimides, polyesters such as polybutylene terephthalate, polyethylene, polypropylene, polystyrene, polycarbonate, polysulfone, polyurethane, silicone, and vinyl ester. This layer is not readily recyclable.

[0011] Furthermore, commercially available aerogel-based insulation materials, such as Tradematt (Henan) Industry's Aerogel Blanket (Model SACB-0-6) or Panasonic Industrial Devices' Nasbis Insulation Sheet (EYGY0912QN3P), have the drawback of generating dust, which is why Nasbis insulation sheets are packaged, which reduces their compressibility.

[0012] Korean Patent Publication No. 2019-0143300 describes an aerogel-insulating composition containing aerogel powder, a fibrous insulating material, and an organic-inorganic composite binder. The fibrous insulating material can be composed of long fibers, short fibers, or a mixture of long and short fibers. The aerogel-insulating composition can be produced by mixing aerogel with the fibrous insulating material and an organic-inorganic binder. A fiber layer may be disposed on one or both sides of the aerogel-insulating composition as a carrier. The fiber layer is relatively thin (10-40 μm), which is detrimental to strength and compressibility. Furthermore, it is difficult to compensate for variations in the thickness of battery cells. Furthermore, the fibers in the binder layer reduce the thermal insulation properties. Additionally, the long fibers tend to entangle, which adversely affects the recyclability of the insulating composition.

[0013] EP 3281968 A1 describes an aerogel-containing composition comprising an aerogel, a water-soluble binder, a blowing agent, and a solvent, the solvent comprising water and a polar organic solvent. The composition preferably contains fibers. The aerogel-containing composition may be applied to a carrier. Again, the fibers in the binder layer reduce thermal insulation. Furthermore, the blowing agent increases the risk of fire and / or is harmful to the environment.

[0014] The problem underlying the present invention is to provide an insulating material for the thermal management of electrochemical cells, particularly lithium-ion cells, cell modules and / or battery systems, which is suitable for the thermal insulation of the aforementioned products and combines high insulating capacity with low thickness and weight. Furthermore, the insulating material is required to be easily recyclable and to meet the requirements imposed on electrochemical cells in terms of dynamic mechanical resistance under compression and thermal insulating capacity. Further problems include the provision of a method for producing the insulating material and its use.

[0015] This problem is solved by an insulating material for electrochemical cells, preferably lithium-ion cells, cell modules and / or battery systems, which comprises an insulating layer comprising a first textile sheet structure, which has a coating containing aerogel particles and at least one binder, wherein the binder is at least partially water-soluble.

[0016] This problem is solved in particular by an insulating material for electrochemical cells, preferably for lithium-ion cells, cell modules and / or battery systems, which comprises an insulating layer comprising a first textile sheet, which has a coating containing aerogel particles and at least one binder, which binder is at least partially water-soluble, and which has a thickness in the range of 0.2 mm to 3.0 mm, measured according to DIN EN ISO 9073-2:1997-02.

[0017] The insulating material according to the present invention is highly suitable for thermally insulating electrochemical cells, preferably lithium-ion cells, cell modules, and / or battery systems, exhibiting high insulating capacity despite its low thickness and weight. A cell module includes at least two interconnected electrochemical cells but does not include a battery management system. A battery system includes at least one electrochemical cell and / or at least one cell module and a battery management system. The insulating material meets the requirements imposed on electrochemical cells in terms of dynamic mechanical resistance under compression and thermal insulating capacity.

[0018] Furthermore, the insulating material is highly recyclable. This is made possible by the fact that, due to the at least partial water solubility of the binder, the insulating material can be easily broken down into its constituent components, for example, by introducing it into water or another suitable solvent. Due to their low density, the aerogel particles float to the surface of the water after the binder has dissolved and can be easily skimmed off, dried, and reused.

[0019] A further advantage of the combination of aerogel with an at least partially water-soluble binder is the large surface area of ​​the aerogel, which allows for a thin binder layer that can be dissolved by water particularly quickly.

[0020] The binder is advantageously at least partially water-soluble. Whether a binder is at least partially water-soluble according to the present invention can be determined using the water solubility measurement described in the Measurement Methods section.

[0021] The proportion of binder is advantageously between 3% and 25% by weight, even more preferably between 3% and 20% by weight, in particular between 5% and 15% by weight, each based on the total weight of the coating.

[0022] The at least partially water-soluble binder can contain a single at least partially water-soluble polymer or a mixture of at least partially water-soluble polymers.

[0023] 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 copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrins, maltodextrins, and copolymers and blends thereof.

[0024] 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, cellulosic binders, preferably methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and chemically modified starches, in particular ethoxylated starches, hydroxypropylated starches, and copolymers and blends thereof.

[0025] Even more especially preferred are at least partially water-soluble binders selected from the group consisting of polyvinyl acetate, partially saponified polyvinyl acetate, polyvinyl alcohol, polyacrylamide, cellulosic binders, preferably methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and chemically modified starches, especially ethoxylated starches, hydroxypropylated starches, and blends thereof.

[0026] Even more especially preferred are at least partially water-soluble binders selected from the group consisting of polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulosic binders, preferably methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and chemically modified starches, especially ethoxylated starches, hydroxypropylated starches, and blends thereof.

[0027] Even more particularly preferred are at least partially water-soluble binders selected from the group consisting of partially saponified polyvinyl acetate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch, hydroxypropylated starch, and copolymers and blends thereof, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 100 mol %, in particular 70 to 100 mol %.

[0028] Even more particularly preferred are at least partially water-soluble binders selected from the group consisting of partially saponified polyvinyl acetate, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 95 mol %, in particular 70 to 95 mol %, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch, hydroxypropylated starch, and copolymers and blends thereof.

[0029] Even more particularly preferred are at least partially water-soluble binders selected from the group consisting of partially saponified polyvinyl acetate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch and hydroxypropylated starch, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 100 mol %, in particular 70 to 100 mol % and blends thereof.

[0030] Even more particularly preferred are at least partially water-soluble binders selected from the group consisting of partially saponified polyvinyl acetate, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 95 mol %, in particular 70 to 95 mol %, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch and hydroxypropylated starch, and blends thereof.

[0031] Even more particularly preferred are at least partially water-soluble binders selected from the group consisting of partially saponified polyvinyl acetate, polyvinyl alcohol, and copolymers and blends thereof, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 100 mol %, in particular 70 to 100 mol %.

[0032] Further especially preferred are at least partially water-soluble binders selected from the group consisting of partially saponified polyvinyl acetate, polyvinyl alcohol and blends thereof, advantageously having a degree of saponification of at least 50 mol %, for example 50-100 mol %, in particular 70-100 mol %.

[0033] In a further particularly preferred embodiment, the at least partially water-soluble binder is a partially saponified polyvinyl acetate and / or polyvinyl alcohol, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 100 mol %, in particular 70 to 100 mol %.

[0034] In a further particularly preferred embodiment, the at least partially water-soluble binder is a partially saponified polyvinyl acetate, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 95 mol %, in particular 70 to 95 mol %.

[0035] The degree of saponification of polyvinyl acetate can be measured using JIS K 6726, 94th edition (October 20, 2017).

[0036] Polyvinyl alcohol (PVOH) is a synthetic polymer that can be produced by hydrolysis or saponification of polyvinyl acetate. PVOH can be produced by complete hydrolysis or saponification of polyvinyl acetate, converting all acetate groups to alcohol groups. Polyvinyl alcohol can be considered a vinyl alcohol homopolymer. PVOH has many hydrogen bonds and is a highly crystalline polymer that dissolves in hot water above approximately 60°C.

[0037] However, hydrolysis of polyvinyl acetate may not be complete if a certain number of acetate groups remain. In this case, partially saponified polyvinyl acetate is formed. Partially saponified polyvinyl acetate has fewer hydrogen bonds than polyvinyl alcohol. The polymer has weaker hydrogen bonds, is less crystalline, and dissolves in cold water. Therefore, partially saponified polyvinyl acetate can also be considered a vinyl alcohol-vinyl acetate copolymer. Preferred partially saponified polyvinyl acetate contains only vinyl alcohol and vinyl acetate groups.

[0038] The coatings described herein can contain, as a binder, one or more polyvinyl alcohols, one or more partially saponified polyvinyl acetates, or a combination thereof. In a preferred embodiment, the binder contains polyvinyl alcohol and / or partially saponified polyvinyl acetate.

[0039] In some embodiments, the binder comprises a polyvinyl alcohol copolymer and / or a copolymer of partially saponified polyvinyl acetate. The polyvinyl alcohol copolymer contains at least one additional monomer unit in addition to vinyl alcohol groups. The partially saponified polyvinyl acetate copolymer contains at least one additional monomer unit in addition to vinyl alcohol and vinyl acetate groups.

[0040] In one embodiment, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate has at least one neutral further monomer unit, in particular ethylene, propylene and / or N-vinylpyrrolidone.

[0041] In a further embodiment, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate has at least one further monomer unit that is cationic.

[0042] In a further embodiment, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate comprises at least one further anionic monomer unit, in particular vinyl polymerized units, vinyl sulfonate monomers and their esters, vinyl monocarboxylic acid monomers, their esters and anhydrides, dicarboxylic acid monomers having a polymerizable double bond, their esters, anhydrides and alkali metal salts of the aforementioned substances.

[0043] Examples of particularly suitable anionic further monomer units are polymerized vinyl units corresponding to anionic vinyl monomers, including vinyl acetic acid, maleic acid, monoalkyl maleates, dialkyl maleates, maleic anhydride, fumaric acid, monoalkyl fumarates, dialkyl fumarates, itaconic acid, monoalkyl itaconates, dialkyl itaconates, citraconic acid, monoalkyl citraconic acid, dialkyl citraconic acid, citraconic anhydride, mesaconic acid, monoalkyl mesaconic acid, dialkyl mesaconic acid, glutaconic acid, monoalkyl glutaconic acid, dialkyl glutaconic acid, glutaconic anhydride, alkyl acrylates, alkyl alkacrylates. Alkylalkacrylate, vinyl sulfonic acid, sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali metal salts of the foregoing (e.g., sodium, potassium or other alkali metal salts), esters of the foregoing (e.g., methyl, ethyl or other C1-C4 or C6-alkyl esters), and combinations of the foregoing (e.g., several anionic monomers or equivalent forms of the same anionic monomer).

[0044] In some embodiments, the polyvinyl alcohol copolymer and / or the copolymer of partially saponified polyvinyl acetate can contain two or more additional monomer units selected from neutral, anionic, and / or cationic monomer units.

[0045] The coatings described herein can contain one or more of the polymers described as a binder.

[0046] In a preferred embodiment, the coating comprises at least one non-white colorant, the advantage of which is that the quality of the coating can be optically assessed in a simple manner.

[0047] More preferably, the first textile sheet comprises glass fibres with a diameter of 1 to 30 μm, even more preferably 5 to 20 μm, even more preferably 7 to 18 μm, especially 7 to 15 μm.

[0048] A further subject of the present invention is a thermal insulation material for electrochemical cells, advantageously for lithium-ion batteries, cell modules and / or battery systems, comprising a thermal insulation layer comprising a first textile sheet, the first textile sheet having a coating containing aerogel particles and a binder, the binder being advantageously at least partially water-soluble and being selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene-olefins, oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrins, maltodextrins, and copolymers and blends thereof, and the first textile sheet is advantageously a thermal insulating material having a thickness in the range of 0.2 mm to 3.0 mm, measured according to DIN EN ISO 9073-2.

[0049] Preferred binders for the insulating material correspond to those mentioned above for the at least partially water-soluble binders.

[0050] Thus, the binder is preferably selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and copolymers and blends thereof.

[0051] More preferably, the binder is preferably selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and copolymers and blends thereof.

[0052] More particularly preferably, the binder is selected from the group consisting of polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulosic binders, preferably methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and chemically modified starches, in particular ethoxylated starches, hydroxypropylated starches, and blends thereof.

[0053] More particularly preferably, the binder is selected from the group consisting of partially saponified polyvinyl acetate, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 95 mol %, in particular 70 to 95 mol %, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch, hydroxypropylated starch and blends thereof.

[0054] In a further especially preferred embodiment, the binder is a partially saponified polyvinyl acetate, advantageously having a degree of saponification of at least 50 mol %, for example 50 to 95 mol %, in particular 70 to 95 mol %.

[0055] In a preferred embodiment of the present invention, the coating comprises a binder which is at least partially water-soluble according to the method defined herein and / or which is advantageously 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, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrins, maltodextrins, and blends thereof, each in an amount of 3% to 25% by weight, advantageously 3% to 20% by weight, in particular 5% to 15% by weight, based on the total weight of the coating.

[0056] In a further preferred embodiment, the insulating material according to the present invention does not have a water-insoluble binder or has a water-insoluble binder in an amount of less than 10 wt.%, preferably less than 7.5 wt.%, in particular less than 5 wt.%, based on the total weight of the coating. The water-insoluble binder is preferably a binder that is at least partially water-insoluble according to the method defined herein. The advantage of this is that it is easily recyclable.

[0057] In a further preferred embodiment, the insulating material according to the invention does not have a water-insoluble binder or only has a water-insoluble binder selected from inorganic binders, in particular from water glass, silica sol, cement, clay minerals and / or binders containing phosphorus (e.g. as phosphates), in an amount of less than 10% by weight, advantageously less than 7.5% by weight, in particular less than 5% by weight, based on the total weight of the coating.

[0058] In a further preferred embodiment, the insulating material according to the invention does not have an inorganic binder or only has inorganic binders in an amount of less than 1 wt. %, advantageously less than 0.5 wt. %, in particular less than 0.1 wt. %, based on the total weight of the coating.

[0059] In a further preferred embodiment, the insulating material according to the invention does not comprise a blowing agent, for example selected from saturated hydrocarbons having 1 to 8 carbon atoms, halogenated hydrocarbons having 1 to 8 carbon atoms and carbon dioxide, or comprises a blowing agent, for example selected from saturated hydrocarbons having 1 to 8 carbon atoms, halogenated hydrocarbons having 1 to 8 carbon atoms and carbon dioxide, only in an amount of less than 1% by weight, advantageously less than 0.5% by weight and in particular less than 0.1% by weight, based on the total weight of the coating.

[0060] In a preferred embodiment of the invention, the coating has no fibers that do not belong to the textile sheet, or only a proportion of less than 5% by weight, even more preferably less than 2.5% by weight, of fibers that do not belong to the textile sheet, based on the total weight of the coating. The advantage of this is a lower thermal conductivity. The fibers that do not belong to the textile sheet are not in contact with the textile sheet in the uncompressed state of the insulating material.

[0061] More preferably, the coating is produced from a precursor material that does not contain fibers or that contains less than 5% by weight, and even more preferably less than 2.5% by weight, of fibers based on the total weight of the precursor material.

[0062] The aerogel particles advantageously comprise inorganic, organic or inorganic-organic hybrid materials.

[0063] In principle, all metal oxides, polymers, and some other materials can be used as starting materials for aerogel synthesis using the sol-gel process. Aerogels can be produced by drying gels made from gel-like materials, preferably silica, under extreme conditions. Aerogels in the broader sense, i.e., "air-borne gels," are produced by drying suitable gels. The term "aerogel" in this sense includes, among others, aerogels and xerogels in the narrower sense. A dried gel is called an aerogel in the narrower sense if the gel liquid is removed at a temperature above the critical temperature and pressure above the critical pressure. The advantage here is that these special drying conditions ensure dimensional stability.

[0064] On the other hand, if the liquid of the gel is removed subcritically, for example, forming a liquid-vapor 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 procedure, dimensional stability can be achieved during the drying process by functionalizing, preferably silanizing, the gel-precursor surface (functionalized aerogel). The advantage of functionalized aerogels is that they can be made hydrophobic through functionalization, and therefore absorb less moisture during use. Furthermore, they can be produced continuously, making them more cost-effective than aerogels in the strict sense.

[0065] It should be noted that the aerogel according to the present invention is an aerogel in the sense of a gel dispersed in air, i.e., in the broad sense. The shaping process of the aerogel is usually completed during the sol-gel transition. After the solid gel structure is formed, the external shape can usually only be changed by fragmentation, for example by grinding, since the material is too brittle to withstand other forms of processing.

[0066] The preferred aerogel particles are made from silica.

[0067] The aerogel particles advantageously have a particle size distribution with a d50 value of 50 μm to 3 mm, even more preferably 200 μm to 3 mm, and / or a d95 value of 50 μm to 10 mm, even more preferably 500 μm to 5 mm, and in particular 750 μm to 2.5 mm. In a further preferred embodiment, the aerogel particles advantageously have a particle size distribution with a d50 value of 5 μm to 300 μm, even more preferably 5 μm to 150 μm, and / or a d95 value of 5 μm to 750 μm, even more preferably 5 μm to 500 μm, and in particular 5 μm to 500 μm. The particle size distribution is measured according to DIN 66165-2:2016-08.

[0068] The coating preferably has a proportion of aerogel particles of at least 60% by weight, for example 60-95% by weight, even more preferably 60-90% by weight, even more preferably 60-85% by weight, in particular 60-80% by weight, each based on the total weight of the coating.

[0069] Also preferably, the insulating material has a proportion of aerogel particles of 6 to 75 wt. %, even more preferably 10 to 70 wt. %, even more preferably 10 to 60 wt. %, even more preferably 15 to 55 wt. %, each based on the total weight of the insulating material.

[0070] According to the present invention, the thermal insulation material comprises a first textile sheet having a coating containing aerogel particles and a binder. Coating is understood to mean that the aerogel particles and binder at least partially cover at least one surface of the first textile sheet. The coating may also at least partially penetrate the first textile sheet. Thus, the coating may be present in an at least partially impregnated state. The coating may be present on one or both surfaces of the first textile sheet. Preferably, it is present on only one surface, so that the textile sheet can provide mechanical protection and / or function as an adhesion aid on the side opposite the coating.

[0071] In a further preferred embodiment, the insulating material has at least one second textile sheet, which can function as a protective layer. In a preferred embodiment, the second textile sheet is arranged on the opposite side of the coating from the first textile sheet. In this way, the textile sheet provides mechanical protection on both sides of the coating.

[0072] The coating may also at least partially penetrate the second textile sheet, and thus be present in the second textile sheet in an at least partially impregnated state, which provides the advantage of better particle organization by allowing the particles to be "wedged" in the spaces between the fibers.

[0073] It is also preferred that the second textile sheet is at least partially located on the outside of the coating, thereby protecting the insulating material from mechanical loads.

[0074] If the thermal insulation material does not have other textile sheet structures in addition to the first textile sheet structure, the proportion of aerogel particles is advantageously up to 75% by weight, for example 10 to 75% by weight, even more preferably 10 to 65% by weight, even more preferably 15 to 65% by weight, even more preferably 15 to 55% by weight, each based on the total weight of the thermal insulation material.

[0075] If the thermal insulation material comprises a second and / or further textile sheet in addition to the first textile sheet, the proportion of aerogel particles is advantageously at least 6% by weight, for example 6-60% by weight, even more preferably 10-60% by weight, even more preferably 10-55% by weight, even more preferably 15-45% by weight, each based on the total weight of the thermal insulation material.

[0076] The coating may further contain one or more additional additives, such as fire retardant additives, in particular additives based on organic nitrogen and / or phosphorus compounds, which are particularly preferred because, in addition to their flame retardant effect, they also have a softening and therefore flexibilizing effect on the polymer.

[0077] The coatings may also contain rheology modifying additives such as wetting agents, e.g., acrylates, acrylamides, cellulosics, dispersing aids, colorants, and / or defoamers, to allow for aqueous coating formulation with, for example, incompatible hydrophobic aerogels.

[0078] In a preferred embodiment of the present invention, the first and / or second textile sheet structure is a nonwoven fabric. A nonwoven fabric is a structure made of fibers of limited length (staple fibers), continuous fibers (filaments), or chopped yarns of any type and origin, joined together in some way to form a fleece (fiber layer, fiber web) and bound together in some way; this does not include the intertwining or entanglement of yarns that occurs during weaving, warp knitting, weft knitting, lace knitting, twill weaving, and tufted product production. Nonwoven fabrics do not include films or papers. Nonwoven fabrics are defined in the standard DIN 61210-2:1988-10.

[0079] Preferably, the first and / or second textile sheet is a wet-laid nonwoven. The advantage here is that wet-laid nonwovens have high isotropy and uniformity. In a further preferred embodiment, the first and / or second textile sheet is a nonwoven, especially a wet-laid nonwoven, from fibers having a staple length of 0.5 to 20 mm, even more preferably 2 to 20 mm, even more preferably 5 to 20 mm, even more preferably 5 to 18 mm, especially 8 to 15 mm. Preferably, the first and / or second textile sheet is a nonwoven, in particular a wetlaid nonwoven, containing at least 50% by weight, even more preferably at least 70% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, and especially 100% by weight, of fibres having a staple length of 0.5 to 20 mm, even more preferably 2 to 20 mm, even more preferably 5 to 20 mm, even more preferably 5 to 18 mm, and especially 8 to 15 mm, in each case based on the total amount of fibres in the textile sheet.

[0080] The advantage of slightly shorter fibres is that they are less likely to entangle with one another and are therefore easier to recycle. The fibre diameter is preferably 1 to 30 μm, even more preferably 5 to 20 μm, even more preferably 7 to 18 μm, especially 7 to 15 μm.

[0081] Also preferably, the first and / or second textile sheet is a nonwoven, in particular a wet-laid nonwoven, which is bound with a binder, in particular an at least partially water-soluble binder. The water solubility of the binder can be measured in the same way as the water solubility of the binder, as explained in the section on measurement methods. Preferably, the binder, in particular the at least partially water-soluble binder, is selected from the polymers described according to the present invention for the at least partially water-soluble binder.

[0082] In one embodiment, the binder is advantageously at least partially water-soluble and is chosen from polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and blends thereof.

[0083] In a further embodiment, the binder is preferably at least partially water-soluble and is selected from the group consisting of polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulosic binders, preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and chemically modified starches, in particular ethoxylated starches, hydroxypropylated starches, and blends thereof.

[0084] In a further embodiment, the binder is preferably at least partially water-soluble and is selected from the group consisting of polyvinyl acetate, partially saponified polyvinyl acetate, polyacrylamide, cellulosic binders, preferably methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and chemically modified starches, in particular ethoxylated starches, hydroxypropylated starches, and blends thereof.

[0085] In a further embodiment, the binder is advantageously at least partially water-soluble and is selected from the group consisting of partially saponified polyvinyl acetate, advantageously having a degree of saponification of at least 50 mol %, for example 50-95 mol %, in particular 70-95 mol %, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch and hydroxypropylated starch, and blends thereof.

[0086] In a further preferred embodiment of the present invention, the first and / or second textile sheet structure contains glass fibers. Preferably, both the first and second textile sheet structure contain glass fibers. The advantage of using glass fibers is that, due to their high density, they sink downward during the recycling process and are thus easily separated from the lighter aerogel particles. Preferably, the proportion of glass fibers, based on the total weight of the insulating material, is 25 to 94 wt.%, even more preferably 35 to 85 wt.%, even more preferably 40 to 75 wt.%, and in particular 50 to 65 wt.%. More preferably, the proportion of glass fibers in the first textile sheet structure, based on the total weight of the first textile sheet structure, is 60 to 98 wt.%, even more preferably 70 to 95 wt.%, and in particular 80 to 95 wt.%. More preferably, the proportion of glass fibers in the second textile sheet is 60 to 98% by weight, even more preferably 70 to 95% by weight, and especially 80 to 95% by weight, based on the total weight of the second textile sheet.

[0087] Advantageously, the glass fibres are staple fibres, preferably having an average fibre length of 2 to 20 mm, even more preferably 5 to 18 mm, in particular 8 to 15 mm. The diameter of the glass fibres is preferably 1 to 30 μm, even more preferably 5 to 20 μm, in particular 7 to 15 μm. The aforementioned staple glass fibres can be used independently of one another in the first and / or second textile sheet structure.

[0088] In a preferred embodiment of the present invention, the first textile sheet is a nonwoven, preferably a wet-laid nonwoven. In a further preferred embodiment of the present invention, the second textile sheet is a nonwoven, preferably a wet-laid nonwoven.

[0089] The first and second textile sheet structures can also, independently of one another, comprise fibers other than glass fibers, in particular binder fibers and / or at least partially water-soluble fibers. Preferred binder fibers and / or at least partially water-soluble fibers are polyvinyl alcohol fibers and / or polyvinyl acetate fibers in which the polyvinyl acetate is partially saponified, advantageously with a degree of saponification of at least 50 mol %, for example 50-100 mol %, in particular 70-100 mol %. Measurements for determining whether a fiber is at least partially water-soluble are explained in the section on measurement methods.

[0090] If present, the proportion of non-glass fibers, in particular at least partially water-soluble fibers, in the first textile sheet is 40 to 2 wt.%, even more preferably 30 to 4 wt.%, even more preferably 25 to 5 wt.%, especially 15 to 5 wt.%, based on the total weight of the first textile sheet. If present, the proportion of non-glass fibers, in particular at least partially water-soluble fibers, in the second textile sheet is 40 to 2 wt.%, even more preferably 30 to 4 wt.%, even more preferably 25 to 5 wt.%, especially 15 to 5 wt.%, based on the total weight of the second textile sheet.

[0091] In one embodiment, the first and second textile sheet structures, independently of one another, contain a combination of both glass and non-glass fibers.

[0092] The at least partially water-soluble fibers can contain a single at least partially water-soluble polymer or a mixture of at least partially water-soluble polymers. Preferred fibers that are not glass fibers are those that contain at least one polymer as described for the at least partially water-soluble binder.

[0093] Preferably, the first textile sheet has a density of 30 g / m 2 as measured in accordance with ISO 9073-1:1989-07. 2 ~300g / m2 and even more preferably in the range of 40 g / m 2 ~300g / m 2 range, especially 50 g / m 2 ~250g / m 2 The advantage here is that the first textile sheet thus has sufficient coverage to ensure good fiber-coating interaction and yet has sufficient strength for further processing.

[0094] Also preferably, the first textile sheet has a thickness, measured according to DIN EN ISO 9073-2:1997-02, in the range of 0.2 mm to 3.0 mm, even more preferably in the range of 0.3 mm to 2.5 mm, and especially in the range of 0.5 mm to 2.0 mm. An advantage of a textile sheet having a relatively low thickness is that it requires less space. Furthermore, this allows the insulating material to contain a relatively large amount of aerogel despite its low overall thickness.

[0095] The advantage of a textile sheet structure with a slightly higher thickness is that it is compressible, has higher strength, and can compensate for variations in thickness of the battery cells.

[0096] In a further preferred embodiment of the invention, the coating is applied to the first textile sheet from an advantageously aqueous dispersion. Advantageously, the dispersion has a solids content in the range of 10-30% by weight, even more preferably 15-25% by weight. The advantage here is that a high solids content can be applied with a relatively small liquid phase at low viscosity.

[0097] In one embodiment, the coating is produced from an advantageously aqueous dispersion that does not contain fibers or that contains fibers only in a proportion of less than 2% by weight, even more preferably less than 1% by weight, in particular less than 0.5% by weight, based on the total weight of the dispersion.

[0098] Preferably, the second textile sheet has a density of 30 g / m2 ~300g / m 2 and even more preferably in the range of 40 g / m 2 ~300g / m 2 range, especially 50 g / m 2 ~250g / m 2 The advantage here is that the textile sheet thus has sufficient coverage to ensure good fiber-coating interaction, yet has sufficient strength for further processing.

[0099] Also preferably, the second textile sheet has a thickness, measured according to DIN EN ISO 9073-2:1997-02, in the range of 0.2 mm to 3.0 mm, preferably in the range of 0.3 mm to 2.5 mm, in particular in the range of 0.5 mm to 2.0 mm. An advantage of a textile sheet having a slightly lower thickness is that it requires less space. An advantage of a textile sheet having a slightly higher thickness is that it is compressible and can compensate for variations in the thickness of the battery cells.

[0100] The second textile sheet preferably has a low maximum tensile strength, measured in accordance with DIN EN ISO 9073-18:2008-08, so that the protected insulating material is flexible. The maximum tensile strength of the second textile sheet is advantageously in the range of 5 to 80 N / 5 cm, preferably in the range of 10 to 70 N / 5 cm, particularly preferably in the range of 15 to 60 N / 5 cm.

[0101] In a further preferred embodiment of the invention, the second textile sheet has a tensile strength at 1 percent elongation in the range of 2 to 60 N / 5 cm, preferably 3 to 50 N / 5 cm, even more preferably 5 to 45 N / 5 cm, even more preferably 10 to 45 N / 5 cm, and especially 10 to 30 N / 5 cm, measured according to DIN EN ISO 9073-18:2008-08, the advantage here being that the strength is low at low elongations, so that the material retains some flexibility.

[0102] The first textile sheet preferably has a maximum tensile strength, measured according to DIN EN ISO 9073-18:2008-08, of at least 30 N / 5cm, preferably in the range of 30 to 1000 N / 5cm, even more preferably 30 to 800 N / 5cm, even more preferably 30 to 400 N / 5cm, even more preferably 30 to 200 N / 5cm, and especially 30 to 100 N / 5cm. The advantage of such a maximum tensile strength is that it provides the insulating material with sufficient strength for processing.

[0103] In a further embodiment of the present invention, the thermal insulation material and / or coating does not have a water-insoluble binder or only has a water-insoluble binder in an amount of less than 10 wt.-%, advantageously less than 7.5 wt.-%, in particular less than 5 wt.-%, based on the total weight of the coating, the water-insoluble binder preferably being a binder that is not water-soluble in the manner defined herein.

[0104] More preferably, the coating is produced from a precursor material which does not comprise a water-insoluble binder or which comprises only a water-insoluble binder in an amount of less than 10 wt. %, advantageously less than 7.5 wt. %, in particular less than 5 wt. %, based on the total weight of the precursor material, the water-insoluble binder preferably being a binder which is not water-soluble in the manner defined herein.

[0105] In a further embodiment of the invention, the thermal insulation material has a flame-retardant layer, which preferably contains a layered silicate, in particular mica. Advantageously, the flame-retardant layer has a flame-retardant density of at least 50 g / m2, measured according to ISO 9073-1:1989-07. 2 , advantageously 60 to 500 g / m 2 , and even more preferably 60 to 300 g / m 2 , especially 70 to 150 g / m 2 Particularly preferably, the flame-retardant layer is arranged in the insulating material so that it presents at least one outer surface of the insulating material.

[0106] In a further embodiment of the invention, the thermal insulation material comprises an infrared reflective layer. Advantageously, the infrared reflective layer is arranged in the thermal insulation material so that it presents at least one outer surface of the thermal insulation material.

[0107] In a further preferred embodiment, the coating and / or the insulating material has a thermal conductivity of at least 50 l / m, measured at 100 Pa according to DIN EN ISO 9237:1995-12. 2 s, e.g. 100 l / m 2 s~600l / m 2 s, preferably 200 l / m 2 s~500l / m 2 s, especially 300 l / m 2 s~400l / m 2 More preferably, the coating and / or insulating material has an air permeability (Δp) of at least 100 l / m s, measured at 200 Pa according to DIN EN ISO 9237:1995-12. 2 s, e.g. 300 l / m 2 s~900l / m 2 s, preferably 400 l / m 2 s~800l / m 2 s, especially 500 l / m 2 s~700l / m 2 It has an air permeability (Δp) of s.

[0108] An advantage of the aforementioned air permeability is that it allows cooling of the insulating material by air convection, which is particularly efficient when the insulating material is not already compressed by the operation of the electrochemical cell.

[0109] In a further preferred embodiment, the coating and / or insulating material has a thickness, measured according to DIN EN ISO 9073-2:1997-02, 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, even more preferably in the range of 1.3 mm to 4 mm or 0.6 mm to 4 mm, in particular in the range of 1.3 mm to 3 mm or 0.6 mm to 3 mm. A thickness of less than 4 mm, in particular less than 3 mm, results in particularly small space requirements.

[0110] In a further preferred embodiment, the insulating material has a thickness of 60 g / m 2 ~900g / m 2 in the range of 70 g / m 2 ~600g / m 2 and even more preferably in the range of 80 g / m 2 ~400g / m 2 range, especially 80 g / m 2 ~200g / m 2 This low weight is advantageous for application in electrochemical cells.

[0111] More preferably, the insulating material has a recyclability score of 1, 2 or 3, as measured as described in the Measurement Methods section.

[0112] More preferably, the insulating material has a thermal conductivity under a pressure load of 20 kPa, measured according to ASTM D 5470-17, of 0.045 to 0.010 W / m·K, even more preferably 0.040 to 0.010 W / m·K, especially 0.036 to 0.010 W / m·K. Still more preferably, the insulating material has a thermal conductivity under a pressure load of 2059 kPa, measured according to ASTM D 5470-17, of 0.035 to 0.010 W / m·K, even more preferably 0.030 to 0.010 W / m·K, especially 0.027 to 0.010 W / m·K.

[0113] In a particularly preferred embodiment, the thermal insulation material comprises an insulating layer comprising a first textile sheet having a coating containing aerogel particles and at least one binder selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonates and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses, such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrins, maltodextrins, and copolymers and blends thereof; the first textile sheet advantageously conforming to DIN EN ISO 14449. 9073-2:1997-02, has a thickness in the range of 0.2 mm to 3.0 mm.

[0114] A preferred embodiment of the aforementioned insulating material is the embodiment described above and below. For example, the binder is preferably at least partially water-soluble. Furthermore, the first textile sheet is preferably a wet-laid nonwoven. Also preferably, the first textile sheet is a nonwoven, advantageously a wet-laid nonwoven, advantageously bound with a binder selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and their salts, polycarbonyl acids and their salts, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and its salts, dextrin, maltodextrin, and blends thereof.

[0115] A further subject of the invention is an electrochemical cell, preferably a lithium-ion cell, which is present thermally insulated by at least one thermal insulating material according to the invention.

[0116] A further subject of the invention is a battery system in which at least one electrochemical cell, advantageously at least one lithium-ion cell, is present, thermally insulated by at least one insulating material according to the invention.

[0117] A further subject of the invention is a cell module and / or battery system in which at least two electrochemical cells are present, thermally insulated from one another by at least one insulating material.

[0118] A further subject of the invention is a method for recycling the insulating material according to the invention, comprising: a1) breaking down the insulating material according to the invention into small pieces and introducing it into a solvent, preferably water, a2) stirring and optionally heating the insulating material according to the invention, a3) Separating the aerogel particles from the fibers of the textile sheet structure The method includes:

[0119] As a solvent, a solvent that at least partially dissolves the binder is suitably used, preferably water.

[0120] The method preferably recycles insulating material according to one or more of the embodiments described herein. Accordingly, preferred embodiments of insulating material recycled according to the method include those described above and below.

[0121] A further subject of the invention is a method for producing a thermal insulating material for an electrochemical cell, comprising the steps of: 1. Providing a first textile sheet having a thickness, advantageously measured according to DIN EN ISO 9073-2:1997-02, in the range of 0.2 mm to 3.0 mm; 2. Coating the textile sheet with a dispersion containing aerogel particles and a binder, the binder comprising: a) is at least partially water-soluble according to the method defined herein, and / or the binder is b) advantageously at least partially water-soluble according to the method defined herein, the binder being selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and copolymers and blends thereof, a coating step; 3. The resulting coating is dried to form a heat insulating layer. The method includes:

[0122] A further subject of the invention is a method for producing a thermal insulating material for an electrochemical cell, 1. Providing a first textile sheet having a thickness, advantageously measured according to DIN EN ISO 9073-2:1997-02, in the range of 0.2 mm to 3.0 mm; 2. Coating a textile sheet with a dispersion containing aerogel particles and a binder, wherein the binder is at least partially water-soluble according to the methods defined herein; 3. The resulting coating is dried to form a heat insulating layer. The method includes:

[0123] Preferred embodiments of the method according to the invention include, mutatis mutandis, the preferred embodiments of the insulating material according to the invention. Thus, the method according to the invention is preferably used to produce insulating materials according to one or more of the embodiments described above and below.

[0124] Thus, in a preferred embodiment, in step 2a following step 2, the thermal insulation layer is provided with at least one second textile sheet that can act as a protective layer. Advantageously, the second textile sheet is placed on the side of the first textile sheet that has the coating.

[0125] The dispersion may further contain rheology modifying additives such as wetting agents, e.g., acrylates, acrylamides, cellulosics, dispersing aids, colorants, and / or defoamers to enable aqueous coating formulation with incompatible hydrophobic aerogels.

[0126] More preferably, the coating of the textile sheet in step 2 is carried out in the form of doctor blade coating.

[0127] A further subject of the present invention is the use of the thermal insulation material according to the invention for the thermal management and / or thermal insulation of electrochemical cells, preferably lithium-ion cells, cell modules and / or battery systems.

[0128] A preferred embodiment of the use according to the invention comprises the preferred embodiment of the thermal insulating material according to the invention mutatis mutandis.

[0129] Measurement method Measurement of binder water solubility A 500 ml Erlenmeyer flask is charged with 300 g of distilled water. 0.5 g of dry binder, preferably with a particle size of 100 μm d90, measured according to DIN 66165-2:2016-08, is added. The flask is placed on a laboratory shaker at 80°C for 24 hours. The number of shakes is selected to keep the mixture moving and replenish the evaporated water. After 24 hours, if a solid phase is present, it is preferably quantitatively separated by filtration. The aqueous phase is concentrated to dryness. If no residue is obtained or if the residue is less than 50 mg, the binder is not water-soluble. If a residue of at least 50 mg is obtained, the binder is at least partially water-soluble.

[0130] Fiber solubility measurement A 500 ml Erlenmeyer flask is charged with 300 g of distilled water. 0.5 g of fiber is then taken. The flask is placed on a laboratory shaker at 80°C for 24 hours. The shaking times are selected to keep the mixture moving and replenish the evaporated water. After 24 hours, if a solid phase is present, it is separated quantitatively, preferably by filtration. The aqueous phase is concentrated to dryness. If no residue is obtained or if the residue is less than 50 mg, the fiber is not water-soluble. If a residue is obtained in an amount of 50 mg or more, the fiber is at least partially water-soluble.

[0131] Measuring recyclability A DIN A4-sized sample (Sample 1) of the material to be measured was taken and cut into small pieces (approximately 2 x 2 cm). This was placed in a 2000 ml beaker and mixed with 1000 ml of water. The water was brought to a boil while stirring vigorously and stirred for an additional 60 minutes. The mixture was then cooled to room temperature (23 °C) while stirring and allowed to phase separate for another 60 minutes. Once separation occurred, the aerogel particle slurry was scooped out and this process was repeated two more times. The aerogel particle slurry was then transferred to a crystallization dish and dried at 120 °C for 6 hours until a constant weight was reached and the mass was measured. If the difference between the mass of the aerogel particles originally present in the sample and the mass determined during the test was less than 25%, the recyclability of the insulation material was scored as 1. If the difference between the mass of the aerogel particles originally present in the sample and the mass determined during the test was 25% to 35%, the recyclability of the insulation material was scored as 2. If the difference between the mass of aerogel particles originally present in the sample and the mass determined during the test is between 35% and 45%, the recyclability of the insulation material is rated a score of 3. If the difference between the mass of aerogel particles originally present in the sample and the mass determined during the test is more than 45%, the recyclability of the insulation material is rated a score of 4.

[0132] The present invention will now be described in more detail with reference to the following non-limiting examples.

[0133] Manufacturing of Sample I A 1000 ml beaker is charged with 60 g of a 5% solution of distilled water and partially saponified polyvinyl acetate (Poval 5-74, Kuraray, 74% saponification degree) and mixed with 0.2 g of a wetting agent based on fatty alcohol ethoxylate (Rucogen D3, Rudolf Chemie). While vigorously stirring with a KPG stirrer, 12 g of SiO2-aerogel particles (Enova IC 3105, Cabot) with a particle size of 0.1-0.5 mm and a hydrophobic surface are added in small portions. After all the particles are incorporated, the resulting paste is coated using a doctor blade at 60 g / m². 2The aerogel particles are then applied to a wet-laid glass fleece with a basis weight of 1.5 mm and dried. The binder in the glass fleece is the same as that used to bind the aerogel particles.

[0134] Fabrication of Sample II: Sample II is prepared in the same way as sample I. After coating, a further layer of glass fleece is applied to the still wet layer, lightly pressed in and subsequently dried.

[0135] Reference Sample 1: Aerogel Blanket: Model No.: SACB-0-6 Company Name: Tradematt (Henan) Industry Shenglong Square, Zhengdong New District Zhengzhou City China

[0136] Reference Sample 2: Nasbis insulation sheet: EYGY0912QN3P (the film included with the product has been removed) Company Name: Panasonic Industrial Devices Two Riverfront Plaza Newark, NJ 07102-5490 US [Table 1]

[0137] Dynamic mechanical load test: Three 25 mm diameter circular specimens were punched, weighed, and placed between two compression plates. A cyclic compressive load was then applied with the following parameters: Climate: 23°C, relative humidity 50% Pressure load: Between plates Static pressure: 0.85 MPa Dynamic pressure (vibration): ±0.65MPa Frequency: 1Hz Number of cycles: 300

[0138] The loaded sample is then removed from the test device, weighed, and optically evaluated. This is done by shaking the sample on white paper (for colored particles) or black paper (for white particles) and evaluating whether the particles have detached from the coating. In the case of laminates, the adhesion of the layers is also evaluated.

[0139] [Table 2]

[0140] conclusion After the dynamic load described, the three measurements of Sample I show no degradation in the sense of aerogel particle precipitation. In the case of the additionally protected layer with a further nonwoven fabric (three measurements of Sample II), the insulating material shows no peeling and no aerogel particle precipitation.

[0141] Reference sample 1 shows aerogel dust already during assembly of the test specimen and shows an increase in aerogel particles on the test plate after loading and in the shake test. Reference sample 2 shows aerogel particles in the shake test.

[0142] Thermal Conductivity Measurement

[0143] [Table 3]

[0144] conclusion Samples 1 and 2 according to the invention provide lower thermal conductivity coefficients over the entire pressure range and therefore have excellent insulating properties.

[0145] Recyclability The recyclability of Sample 1 was determined using the above method and was given a score of 1. Reference Sample 1 was given a score of 4.

Claims

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

2. 1. A thermal insulation material for electrochemical cells, preferably lithium-ion cells, comprising a thermal insulation layer comprising a first textile sheet, said first textile sheet having a coating containing aerogel particles and at least one binder, 1. A thermal insulating material, characterized in that the binder is advantageously 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, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses, such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and copolymers and blends thereof, and the first textile sheet advantageously has a thickness in the range of 0.2 mm to 3.0 mm, measured according to DIN EN ISO 9073-2:1997-02.

3. 3. The heat insulating material according to claim 1 or 2, characterized in that the binder is advantageously selected from the group consisting of partially saponified polyvinyl acetate, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethoxylated starch and hydroxypropylated starch, and copolymers and blends thereof, having a degree of saponification of at least 50 mol %, for example 50 to 100 mol %, preferably 70 to 100 mol %, according to IS K 6726, 94th edition (20.10.2017).

4. 4. The insulating material according to claim 1, wherein the binder is advantageously selected from the group consisting of partially saponified polyvinyl acetates having a degree of saponification of at least 50 mol %, for example 50 to 95 mol %, preferably 70 to 95 mol %, according to IS K 6726, 94th edition (20.10.2017), and copolymers and blends thereof.

5. 5. The thermal insulation material according to claim 1, wherein the coating at least partially penetrates the first textile sheet.

6. 6. The insulating material according to claim 1, wherein the insulating material comprises at least one second textile sheet arranged on the side of the coating opposite the first textile sheet.

7. 7. The thermal insulation material according to claim 1, wherein the coating at least partially penetrates the second textile sheet.

8. 8. The thermal insulation material according to claim 1, wherein a second textile sheet is at least partially outside the coating.

9. 9. The insulating material according to claim 1, wherein the aerogel particles have a particle size distribution with a d50 value of 50 μm to 3 mm, measured according to DIN 66165-2:2016-08.

10. 10. The thermal insulation material according to claim 1, wherein the coating has a proportion of aerogel particles of at least 60% by weight, for example 60-95% by weight, based on the total weight of the coating, and / or the thermal insulation material has a proportion of aerogel particles of 6-75% by weight, based on the total weight of the thermal insulation material.

11. 11. A thermal insulation material according to any one or more of the preceding claims, characterized in that the first and / or second textile sheet structure is a nonwoven fabric, which is advantageously at least partially bound with a water-soluble binder according to the method defined herein.

12. 12. The insulating material according to claim 1, wherein the first textile sheet is a nonwoven, preferably a wet-laid nonwoven, which is bound with a binder selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and blends thereof.

13. 13. The thermal insulation material according to any one or more of the preceding claims, characterized in that the first and / or second textile sheet structure is a wet-laid nonwoven, which is advantageously at least partially bound with a water-soluble binder according to the method defined herein.

14. 14. The insulating material according to claim 1, wherein the first and / or second textile sheet contains glass fibers, preferably with an average fiber length of 2 to 20 mm.

15. 15. The insulating material according to claim 1, wherein the first and / or second textile sheet has a thickness, measured according to DIN EN ISO 9073-2:1997-02, in the range of 0.2 mm to 3.0 mm, preferably in the range of 0.3 mm to 2.5 mm, in particular in the range of 0.5 mm to 2.0 mm.

16. 16. The insulating material according to claim 1, wherein the insulating material does not have a water-insoluble binder or only has a water-insoluble binder in an amount of less than 10 wt.-%, advantageously less than 7.5 wt.-%, in particular less than 5 wt.-%, based on the total weight of the coating, the water-insoluble binder preferably being at least partially water-insoluble according to the method defined herein.

17. 17. An electrochemical cell, preferably a lithium-ion cell, present in a state thermally insulated by at least one insulating material according to claim 1, and / or a battery system in which at least one electrochemical cell, preferably at least one lithium-ion cell, is present in a state thermally insulated by at least one insulating material according to claim 1.

18. 17. A cell module and / or battery system, in which at least two electrochemical cells are present, thermally insulated from one another by at least one insulating material according to any one or more of claims 1 to 16.

19. 1. A method for producing a thermal insulating material for an electrochemical cell, comprising: a) providing a first textile sheet, advantageously having a thickness in the range of 0.2 mm to 3.0 mm, measured according to DIN EN ISO 9073-2:1997-02; b) coating the textile sheet with a dispersion containing aerogel particles and a binder, the binder comprising: b1) is at least partially water-soluble according to the method defined herein, and / or said binder is b2) Advantageously, said binder is at least partially water-soluble according to the method defined herein, said binder being selected from the group consisting of polyvinyl acetate, preferably partially saponified polyvinyl acetate, polyvinyl alcohol, acrylate copolymers, polyvinylpyrrolidone, polyethyleneimine, polyalkylene oxides, polyacrylamides, polyacrylic acids and salts thereof, polycarbonyl acids and salts thereof, polyamino acids, modified starches, ethoxylated starches, hydroxypropylated starches, modified celluloses, such as cellulose ethers, cellulose esters, cellulose amides, copolymers thereof, pullulan, guar gum, gum arabic, xanthan, carrageenan, cellulose, gelatin and salts thereof, dextrin, maltodextrin, and copolymers and blends thereof, a coating step; c) drying the resulting coating to form a thermal insulating layer A method comprising:

20. 17. A method for recycling insulation material according to any one or more of claims 1 to 16, comprising the steps of: a1) breaking down the insulating material and introducing it into a solvent, preferably water; a2) stirring and optionally heating the insulating material; a3) Separating the aerogel particles from the fibers of the textile sheet structure. A method comprising:

21. 17. Use of a thermal insulating material according to one or more of claims 1 to 16 for the thermal management and / or thermal insulation of electrochemical cells, preferably lithium-ion cells, cell modules and / or battery systems.

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