Heat insulating sheet for batteries, manufacturing method thereof, and battery module including the same

Abstract

To provide an insulation sheet for batteries having excellent thermal insulation, fire resistance, and flame retardancy or non-flammability to inhibit propagation of heat in a cell to cells adjacent thereto due to thermal runaway of a battery, a method of manufacturing the same, and a battery module including the same.SOLUTION: The present invention relates to an insulation sheet for batteries. The insulation sheet includes an aerogel layer including an aerogel and a coating layer covering the entire surface of the aerogel layer. The coating layer includes a flexible polymer and a flame retardant dispersed in the flexible polymer, and has an elastic modulus measured in accordance with ASTM D882 of 8 MPa or less. The present invention further relates to a method of manufacturing the insulation sheet, and a battery module including the insulation sheet.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat insulating sheet for a battery, a method for manufacturing the same, and a battery module including the same. [Background technology]

[0002] Secondary batteries are power storage systems that offer excellent energy density by converting electrical energy into chemical energy and storing it. Unlike primary batteries, which cannot be recharged, secondary batteries are rechargeable and are widely used in IT devices such as smartphones, cellular phones, laptops, and tablet PCs. In recent years, interest in electric vehicles has grown to prevent environmental pollution, and high-capacity secondary batteries are being adopted for electric vehicles. Such secondary batteries are required to have characteristics such as high density, high output, and stability.

[0003] On the other hand, when a battery contains a large number of high-capacity battery cells such as lithium-ion secondary batteries, one battery cell may overheat for some reason and experience thermal runaway, adversely affecting other adjacent battery cells, so it is necessary to thermally insulate adjacent battery cells from each other.

[0004] Therefore, conventionally, plates or insulating resin plates are placed between the battery cells to insulate and heat the adjacent battery cells.

[0005] The above-mentioned information disclosed in the background of the invention is merely intended to enhance understanding of the background of the invention, and therefore may include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0006] One embodiment provides a battery insulating sheet that has excellent heat insulating properties as well as fire resistance and flame retardancy or non-combustibility to suppress heat propagation to adjacent cells due to thermal runaway of the battery, a manufacturing method thereof, and a battery module including the same. [Means for solving the problem]

[0007] One embodiment provides a heat insulating sheet for a battery, comprising: an aerogel layer containing an aerogel; and a coating layer covering the entire surface of the aerogel layer, wherein the coating layer comprises a flexible polymer and a flame retardant dispersed in the flexible polymer, and the coating layer has an elastic modulus of 8 MPa or less as measured according to ASTM D882.

[0008] The aerogel has a BET specific surface area of ​​500 m 2 / g~1,000m 2 / g.

[0009] The aerogel layer may further include a fibrous support and a functional material including a binder, a dispersant, or a combination thereof.

[0010] The fibrous support may be one or more fibers selected from the group consisting of natural fibers, silica fibers, glass fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

[0011] The binder may include a water-based polymeric binder.

[0012] The dispersant may be one or more selected from the group consisting of surfactants, silane coupling agents, and phosphate salts.

[0013] The aerogel layer may contain 10% by weight to 90% by weight of the aerogel, 5% by weight to 70% by weight of the fibrous support, and 0.5% by weight to 20% by weight of the functional material, based on the total amount of the aerogel layer.

[0014] The flexible polymer may be at least one selected from the group consisting of fluorine-based polymers, polyurethane-based polymers, polyolefin-based polymers, and silicon-based polymers.

[0015] The flame retardant may be one or more selected from the group consisting of inorganic flame retardants, phosphorus-based flame retardants, nitrogen compound-based flame retardants, silicon-based flame retardants, melamine-based flame retardants, halogen-based flame retardants, and polyhydric alcohol-based flame retardants.

[0016] The flame retardant may be a phosphorus-based flame retardant and a polyhydric alcohol-based flame retardant.

[0017] The flame retardant may include a phosphorus-based flame retardant and a polyhydric alcohol-based flame retardant in a weight ratio of 1:0.1 to 1:0.5.

[0018] The content of the flame retardant may be 1% by weight to 25% by weight with respect to the total amount of the coating layer.

[0019] The coating layer may be free of fillers.

[0020] The thickness of the coating layer may be 20% or less of the total thickness of the battery insulating sheet.

[0021] The flexible polymer may be one or more selected from the group consisting of polyurethane-based polymers and silicone-based polymers, and the flame retardant may be one or more selected from the group consisting of polyhydric alcohol-based flame retardants and phosphorus-based flame retardants.

[0022] Another embodiment provides a method for manufacturing an insulating sheet for a battery, the method including: forming an aerogel layer including an aerogel; and forming a coating layer to cover an entire surface of the aerogel layer, the coating layer including a flexible polymer and a flame retardant dispersed in the flexible polymer.

[0023] Yet another embodiment provides a battery module including a plurality of cells and the heat insulating sheets disposed between the plurality of cells, respectively. [Effects of the Invention]

[0024] The battery insulating sheet according to one embodiment has excellent heat insulating properties, fire resistance, and flame retardancy or non-combustibility, and can suppress the spread of heat and flame to adjacent cells due to thermal runaway in one cell.

[0025] In addition, the insulating sheet for a battery according to one embodiment has excellent compressibility, and can ensure mechanical strength and dimensional stability. It can prevent the aerogel layer from falling off due to external impact, and can improve workability and prevent contamination of the mechanism. [Brief explanation of the drawings]

[0026] [Figure 1] 2 is a schematic diagram showing an embodiment of a battery insulating sheet formed between a plurality of cells. FIG. [Figure 2] 1 is a schematic diagram showing a cross-sectional structure of a battery insulating sheet according to one embodiment. [Figure 3] 10 is a schematic diagram showing the cross-sectional structure of a heat insulating sheet according to Comparative Example 4. FIG. [Figure 4] 10 is a schematic diagram showing the cross-sectional structure of a heat insulating sheet according to Comparative Example 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0027] Although the present invention will be described in detail below so that those skilled in the art can easily implement the present invention, it should be understood that the present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0028] Insulation is a material that prevents heat from moving from high temperature areas to low temperature areas, and is used in refrigerators, freezer warehouses, buildings, and various industrial fields including the aircraft, electronic parts, and automotive industries.

[0029] Such a heat insulating material must have excellent heat insulating properties due to low thermal conductivity, and must also have sufficient mechanical strength to maintain such heat insulating properties.

[0030] Meanwhile, aerogel is a transparent or translucent cutting-edge material with a nanoporous structure, and has very low density and low thermal conductivity. As such, it not only has great potential as an insulating material, but is also being evaluated as a highly efficient super-insulating material that can be used in various industrial fields.

[0031] Furthermore, the greatest advantage of aerogel is that it exhibits lower thermal conductivity than conventional organic insulation materials such as styrofoam, and that it can solve the fatal weaknesses of organic insulation materials, namely their vulnerability to fire and the generation of harmful gases during a fire.

[0032] According to one embodiment, an insulating sheet for a battery includes an aerogel layer containing an aerogel, and a coating layer covering the entire surface of the aerogel layer. The coating layer includes a flexible polymer and a flame retardant dispersed in the flexible polymer, and the coating layer may have an elastic modulus of 8 MPa or less as measured according to ASTM D882.

[0033] The battery insulation sheet having the above structure has excellent thermal insulation properties and is fire-resistant and flame-retardant or non-flammable, thereby preventing the spread of heat and flame from one cell to an adjacent cell due to thermal runaway. Furthermore, the battery insulation sheet has excellent compressibility, ensuring mechanical strength and dimensional stability, and preventing the aerogel layer from falling off due to external impact, thereby improving workability and preventing contamination of the mechanism.

[0034] In one embodiment, the aerogel has a BET specific surface area of ​​500 m 2 / g~1,000m 2 For example, the aerogel may have a BET specific surface area of ​​500 m 2 / g~950m 2 / g, 550m 2 / g~950m2 / g, or 600m 2 / g~900m 2 By including an aerogel having a BET specific surface area within the above range, scattering of the aerogel particles can be prevented and heat insulation can be improved.

[0035] The particle size of the aerogel may be 5 μm to 200 μm, 10 μm to 100 μm, or 20 μm to 60 μm. By including aerogel having a particle size within the above range, the heat insulating properties can be improved and heat transfer between the multiple cells can be delayed.

[0036] The content of the aerogel may be 10 to 90% by weight, 30 to 70% by weight, or 40 to 60% by weight, based on the total weight of the aerogel layer. By including an aerogel layer containing aerogel within this range, excellent heat insulating properties of the battery insulating sheet can be obtained.

[0037] In one embodiment, the aerogel layer may further comprise a fibrous support and a functional material comprising a binder, a dispersant, or a combination thereof.

[0038] The fibrous support is contained in the aerogel layer, thereby improving the durability of the battery insulation sheet formed using the same.

[0039] The fibrous support may include fibers commonly used as supports for insulating materials. For example, the fibrous support may be one or more fibers selected from the group consisting of natural fibers, silica fibers, glass fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers. As a specific example, the fibrous support may include, but is not limited to, glass fibers.

[0040] The natural fiber may be, for example, one or more fibers selected from the group consisting of hemp, jute, flax, coir, hemp, and cellulose.

[0041] The mineral fibers may be, for example, mineral fibers containing one or more selected from the group consisting of basalt, wollastonite, alumina, silica, slag, and rock.

[0042] The polymer fiber may be, for example, one or more selected from the group consisting of nylon, polyimide, polyamide, polybenzimidazole, polybenzoxazole, polyamideimide, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyethylene (PE), and polypropylene (PP). Specific examples of the polymer fiber include, but are not limited to, one or more selected from the group consisting of polyimide, polyamide, and polybenzimidazole.

[0043] The fibrous support may be, for example, in the form of wool or chopped strands, but is not limited thereto.

[0044] The average particle size (D50) of the fibrous support may be, for example, 0.1 μm to 20 μm, 0.1 μm to 15 μm, 0.1 μm to 5 μm, 1 μm to 15 μm, or 3 μm to 10 μm. By including a fibrous support having an average particle size within the above range, the structure of the aerogel layer can be made stronger, and production costs can be reduced.

[0045] The average particle size (D50) can be measured, for example, using a laser diffraction method or a scanning electron microscope (SEM) photograph, and the average particle size (D50) of particles can be defined as the particle size at 50% of the particle size distribution (the particle size corresponding to 50% of the cumulative volume of the particle size distribution).

[0046] The content of the fibrous support may be 5 to 70% by weight, 25 to 60% by weight, or 30 to 50% by weight, based on the total weight of the aerogel layer. When an aerogel layer containing a fibrous support within the above range is formed to produce a battery insulating sheet, durability can be improved.

[0047] The binder may include a water-based polymer binder. For example, the water-based polymer binder may be one or more selected from the group consisting of aqueous polymers, anionic water-soluble polymers, cationic water-soluble polymers, and water-dispersible polymers.

[0048] The aqueous polymer may be, for example, one or more selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinylpyrrolidone, but is not limited thereto.

[0049] The anionic water-soluble polymer may be one or more selected from the group consisting of polymers having functional groups such as carboxylic acid, sulfonic acid, sulfate, phosphate, and salts thereof. For example, the anionic water-soluble polymer may be a polymer having a carboxylic acid group, and a specific example thereof may include, but is not limited to, polymaleic acid.

[0050] The cationic water-soluble polymer may be at least one selected from the group consisting of polymers having functional groups such as amine, ammonium, phosphonium, sulfonium, and salts thereof. For example, the cationic water-soluble polymer may be a polymer having an amine group, and specific examples thereof include, but are not limited to, at least one selected from the group consisting of polyethylene amine and polyamine.

[0051] The water-dispersible polymer may be at least one selected from the group consisting of water-dispersible polyurethane and water-dispersible polyester, but is not limited thereto.

[0052] The binder may include a water-based polymer and a water-dispersible polymer, for example, a water-based polymer having binder properties and dispersing properties, and a water-dispersible polyurethane having fire-resistant properties, and a specific example thereof may include polyvinyl alcohol and water-dispersible polyurethane.

[0053] The weight ratio of the aqueous polymer to the water-dispersible polymer may be 1:1 to 1:5, 1:1 to 1:4, or 1:2 to 1:3. When the weight ratio of the aqueous polymer to the water-dispersible polymer is within this range, the heat insulation properties, dust resistance, and compressibility of the heat insulating sheet can be further improved, as well as the fire resistance and mechanical properties.

[0054] The content of the binder may be 0.5 to 20% by weight, 2 to 15% by weight, or 8 to 15% by weight, based on the total weight of the aerogel layer. A battery insulating sheet including an aerogel layer containing a binder within this range can have improved dust resistance.

[0055] The dispersant may be at least one selected from the group consisting of a surfactant, a silane coupling agent, and a phosphate salt. Specific examples of the dispersant include, but are not limited to, at least one of a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, a natural surfactant such as lecithin, and a phosphate salt.

[0056] When the dispersant is further included, the dispersion of the aerogel is improved during the preparation of the aerogel layer, and the aerogel and the fibrous support can be uniformly dispersed.

[0057] The content of the dispersant may be 0.1 to 6 wt %, 0.1 to 5 wt %, or 0.1 to 3 wt %, based on the total weight of the aerogel layer. By including a dispersant within this range, an aerogel layer can be produced at low cost, and a heat insulating sheet having excellent heat insulating properties, uniformity, and dust resistance can be produced using the aerogel layer.

[0058] In one embodiment, the binder and the dispersant may be included in a weight ratio of 1:0.001 to 1:0.67, 1:0.001 to 1:0.5, or 1:0.001 to 1:0.3. When the binder and the dispersant are used in combination in a weight ratio within this range, the aerogel may be more uniformly dispersed in the aerogel layer.

[0059] In one embodiment, the aerogel layer may contain 25% by weight to 60% by weight of the fibrous support, 30% by weight to 70% by weight of the aerogel, and 2% by weight to 15% by weight of the binder, relative to the total amount of the aerogel layer.

[0060] As a specific example, the aerogel layer may contain 30 to 50% by weight of the fibrous support, 40 to 60% by weight of the aerogel, and 8 to 15% by weight of the binder, relative to the total weight of the aerogel layer. When the aerogel layer is formed within these ranges, excellent heat insulation can be achieved, durability can be improved, the bonding strength between the fibrous support and the aerogel can be improved, and dust generation can be prevented.

[0061] In one embodiment, the aerogel layer may contain 25% by weight to 60% by weight of the fibrous support, 30% by weight to 70% by weight of the aerogel, 2% by weight to 15% by weight of the binder, and 0.1% by weight to 3% by weight of the dispersant, relative to the total amount of the aerogel layer.

[0062] As a specific example, the aerogel layer may contain 30 to 50% by weight of the fibrous support, 40 to 60% by weight of the aerogel, 5 to 10% by weight of the binder, and 0.1 to 2% by weight of the dispersant, relative to the total amount of the aerogel layer. When the aerogel layer is formed within these ranges, excellent heat insulation can be achieved, durability can be improved, the bonding strength between the fibrous support and the aerogel can be improved, and dust generation can be prevented.

[0063] In one embodiment, the flexible polymer contained in the coating layer is not particularly limited as long as it is a polymer having flexibility, and may be, for example, one or more polymers selected from the group consisting of fluorine-based polymers, polyurethane-based polymers, polyolefin-based polymers, and silicone-based polymers.

[0064] The fluoropolymer may be, for example, one or more selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxyethylene (PFA), fluoroethylenepropylene (FEP), ethylene-tetrafluoroethylene (ETFE), polyvinyldene fluoride (PVDF), and polychlorotrifluoroethylene (PCTFE). The fluoropolymer may be a substance that is flexible and independently flame-retardant.

[0065] The polyurethane polymer is not particularly limited as long as it is a conventional polyurethane produced by polymerization of a polyol and a polyisocyanate. Here, the polyol may be, for example, a conventional polyol used in the production of polyurethane, and may be one or more selected from the group consisting of polyether polyol, polyester polyol, polyamide polyol, polyesteramide polyol, polythioether polyol, polycarbonate polyol, polyacetal polyol, polyolefin polyol, polysiloxane polyol, acrylic polyol, and silicone polyol. Furthermore, the polyisocyanate may include, for example, a typical polyisocyanate used in the production of polyurethane, and may be one or more selected from the group consisting of toluene diisocyanate, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 4,4-dicyclohexylmethane diisocyanate, 4,4-di(aminocyclohexyl)methane hexamethylene diisocyanate, 1,4-phenylene diisocyanate, 4,4-diphenylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, trimethylhexamethylene diisocyanate, and norborane diisocyanate.

[0066] The polyolefin polymer may be, for example, one or more selected from the group consisting of polyethylene, polypropylene, polybutylene, polypentene, polyvinylidene fluoride, and polymethyl methacrylate.

[0067] The silicon-based polymer may be, for example, one or more selected from the group consisting of silicon elastomer, polydimethylsiloxane, polymethylethylsiloxane, polydiethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and polyethylphenylsiloxane.

[0068] The content of the flexible polymer may be 75 to 99 wt %, 90 to 97 wt %, or 94 to 97 wt % of the total amount of the coating layer. By forming a coating layer containing a flame retardant within this range on the surface of an aerogel layer with excellent thermal insulation, the battery insulation sheet can have fire resistance and flame resistance or non-combustibility in addition to thermal insulation properties.

[0069] The coating layer may further include a flame retardant, and the type of the flame retardant is not particularly limited and may be, for example, at least one selected from the group consisting of inorganic flame retardants, phosphorus-based flame retardants, nitrogen compound-based flame retardants, silicon-based flame retardants, melamine-based flame retardants, halogen-based flame retardants, and polyhydric alcohol-based flame retardants.

[0070] The inorganic flame retardant may be at least one selected from the group consisting of metal oxides and metal hydroxides, for example, but is not limited to, silicon oxide, magnesium hydroxide, aluminum hydroxide, antimony oxide, sodium carbonate, zinc oxide, iron oxide, tin oxide, zinc borate, and calcium borate.

[0071] The phosphorus-based flame retardant includes a conventional phosphorus-containing flame retardant, for example, one or more selected from the group consisting of phosphate, phosphonate, phosphinate, phosphine oxide, phosphazene, and ammonium salts thereof, but is not limited thereto.

[0072] The phosphorus-based flame retardant may have two or more hydroxyl groups at the functional group terminal. As a specific example, the phosphorus-based flame retardant may include ammonium phosphate having a multifunctional hydroxyl group. The use of a phosphorus-based flame retardant having a multifunctional hydroxyl group can provide excellent flame retardancy.

[0073] The nitrogen compound-based flame retardant may be at least one selected from the group consisting of an aliphatic amine compound, an aromatic amine compound, a nitrogen-containing heterocyclic compound, a cyanide compound, an ammonium hydroxide, an aliphatic amide, an aromatic amide, urea, and thiourea, but is not limited thereto.

[0074] The silicone flame retardant may be one or more selected from the group consisting of silicone resins and silicone oils. The silicone resin may include a resin having an RSiO structure, where R represents an alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, or a propyl group; an aromatic group; or a substituent in which one or more hydrogen atoms of the alkyl group and aromatic group are substituted with a vinyl group. The silicone oil may be, but is not limited to, one or more selected from the group consisting of polydimethylsiloxane and modified polydimethylsiloxane in which at least one methyl group on the side chain or terminal of polydimethylsiloxane is modified with one or more of hydrogen, alkyl group, cyclohexyl group, phenyl group, benzyl group, epoxy group, polyether group, carboxyl group, mercapto group, chloroalkyl group, alkyl alcohol ester group, alcohol group, allyl group, vinyl group, and trifluoromethyl group.

[0075] The melamine-based flame retardant may be at least one selected from the group consisting of melamine phosphate, dimelamine phosphate, melamine pyrophosphate, and melamine cyanurate, but is not limited thereto.

[0076] The halogen-based flame retardant may be any halogen-based compound that can function as a flame retardant, and may be, but is not limited to, at least one selected from the group consisting of decabromodiphenyl ether, decabromodiphenylethane, tetrabromobisphenol-A, tetrabromobisphenol-A epoxy oligomer, octabromotrimethylphenylindane, ethylene-bis-tetrabromophthalimide, tris(tribromophenol)triazine, and brominated polystyrene.

[0077] The polyhydric alcohol flame retardant may be, for example, one or more selected from the group consisting of pentaerythritol, dipentaerythritol, trimethylolpropane, and ethylene glycol. As a specific example, the polyhydric alcohol flame retardant may be dipentaerythritol.

[0078] The flame retardant may be a phosphorus-based flame retardant or a polyhydric alcohol-based flame retardant, in which case flame retardancy can be ensured without emitting harmful substances.

[0079] The flame retardant may contain a phosphorus-based flame retardant and a polyhydric alcohol-based flame retardant in a weight ratio of 1:0.1 to 1:0.5, 1:0.1 to 1:0.4, 1:0.15 to 1:0.35, or 1:0.15 to 0.25. When the phosphorus-based flame retardant and the polyhydric alcohol-based flame retardant are used in combination within the above ranges, the coating layer has an excellent elastic modulus and the flame retardancy of the heat insulating sheet can be improved.

[0080] The content of the flame retardant may be 1 to 25% by weight, 3 to 10% by weight, or 3 to 6% by weight, based on the total weight of the coating layer. By forming a coating layer containing a flame retardant within this range on the surface of an aerogel layer with excellent thermal insulation properties, the battery insulation sheet can have fire resistance and flame resistance or non-combustibility in addition to thermal insulation properties.

[0081] The coating layer may be free of a filler, which may be, but is not limited to, at least one selected from the group consisting of fumed silica, diatomaceous earth, halloysite, carbon nanotubes, perlite, silica, alumina, barium sulfate, clay, talc, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, and vermiculite.

[0082] The aerogel layer may be a hexahedron having an upper surface, a lower surface, and a side surface of an edge region between the upper surface and the lower surface, and a coating layer may be formed so as to cover the entire surface of the aerogel layer.

[0083] As a specific example, the coating layer may cover the entire surface of the aerogel layer, including all of the top, bottom, and side surfaces. Battery insulation sheets having a coating layer formed to cover the entire surface of the aerogel layer may be disposed between a plurality of cells, with the top and bottom surfaces of the battery insulation sheet facing the cells disposed on both sides of the battery insulation sheet. Furthermore, since the flame-retardant coating layer is formed on the entire surface of the battery insulation sheet, the insulation sheet can prevent the insulation sheet from burning independently, and can first block the flame when one cell overheats, thereby preventing the flame from spreading to adjacent cells. This can also effectively prevent the flame from spreading within a battery module having a plurality of cells.

[0084] The thickness of the coating layer may be 20% or less, 1% to 20%, 5% to 17%, or 8% to 12% of the total thickness of the battery insulation sheet. By forming the coating layer with a thickness within this range, the battery insulation sheet can have excellent heat insulation properties as well as flame retardancy or non-combustibility.

[0085] The coating layer includes the flexible polymer and a flame retardant dispersed in the flexible polymer, the flexible polymer being at least one selected from the group consisting of polyurethane-based polymers and silicone-based polymers, and the flame retardant being at least one selected from the group consisting of polyhydric alcohol-based flame retardants and phosphorus-based flame retardants. In this case, the aerogel layer can be prevented from falling off or scattering due to external impact, improving workability and preventing contamination of the mechanism. In addition to excellent thermal insulation, the coating layer can also be flame-retardant or non-combustible.

[0086] In one embodiment, the coating layer may have a modulus of elasticity of 8 MPa or less as measured by ASTM D 882. Specifically, the coating layer may have a modulus of elasticity of 1 MPa to 8 MPa, 3 MPa to 7 MPa, or 3 MPa to 5 MPa as measured by ASTM D 882.

[0087] According to one embodiment, a method for manufacturing an insulating sheet for a battery includes forming an aerogel layer containing an aerogel; and forming a coating layer to cover an entire surface of the aerogel layer. The coating layer may include a flexible polymer and a flame retardant dispersed in the flexible polymer, and the coating layer may have an elastic modulus of 8 MPa or less as measured according to ASTM D882.

[0088] In one embodiment, forming the aerogel layer may include mixing a functional material, including a binder, a dispersant, or a combination thereof, with a solvent to prepare a solvent mixture; mixing the solvent mixture and an aerogel to prepare an aerogel mixture; and mixing the aerogel mixture and a fibrous support to prepare an aerogel composition.

[0089] In the step of preparing the solvent mixture by mixing the functional material with the solvent, a binder may be mixed with the solvent, or a binder and a dispersant may be mixed with the solvent.

[0090] The solvent may be one or more selected from the group consisting of polar solvents and non-polar solvents.

[0091] The polar solvent may be one or more selected from the group consisting of water and alcohol-based solvents.

[0092] The water may be, for example, one or more types selected from the group consisting of purified water and ultrapure water.

[0093] The alcohol-based solvent may be, for example, one or more selected from the group consisting of methanol, ethanol, propanol, pentanol, butanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol, and glycerol, but is not limited thereto.

[0094] The non-polar solvent may include a hydrocarbon solvent, for example, at least one selected from the group consisting of hexane, pentane, heptane, toluene, and benzene, and more preferably, an alkane solvent such as hexane, or a mixture containing an alkane solvent, but is not limited thereto.

[0095] The solvent may include water. Using water as a solvent can effectively reduce raw material costs and post-processing costs. However, when water is used as a solvent, it can be difficult to mix with hydrophobic aerogel. In one embodiment, however, the aerogel is uniformly dispersed by controlling the mixing step design, mixing conditions, and the addition and amounts of binder and dispersant. By uniformly dispersing the aerogel in the composition in this manner, a thin insulating sheet for a battery with excellent insulation properties, durability, and low dusting can be formed without using a large amount of binder.

[0096] The solvent may be contained in such a way that the weight ratio of the solvent to the total solid content of the aerogel composition is 1:1 to 1:90. For example, the weight ratio of the solvent to the total solid content of the aerogel composition may be 1:50 to 1:70, 1:20 to 1:30, or 1:2 to 1:10. By controlling the weight ratio of the solvent to the total solid content within the above range, it is possible to achieve a balance between dispersibility, coatability, and phase stability.

[0097] The specific explanation regarding the binder and dispersant may be as described above.

[0098] In the step of preparing the aerogel mixture by mixing the solvent mixture and the aerogel, the specific description of the aerogel may be the same as that described above.

[0099] In the step of preparing an aerogel composition by mixing the aerogel mixture and the fibrous support, the specific description of the fibrous support may be the same as that described above.

[0100] In each of the steps of preparing a solvent mixture by mixing a functional material, such as a binder, a dispersant, or a combination thereof, with the solvent, preparing an aerogel mixture by mixing the solvent mixture with an aerogel, and preparing an aerogel composition by mixing the aerogel mixture with a fibrous support, a mixer may be used during mixing. For example, the mixer may include, but is not limited to, a planetary mixer, a PD mixer, a thinky mixer, a C-mixer, etc.

[0101] For example, a planetary mixer may be used to mix the solvent mixture and the aerogel. By using the planetary mixer to mix the solvent mixture and the aerogel, the aerogel can be uniformly dispersed in the solvent.

[0102] The planetary mixer may be a device that can be used to mix or stir different materials to produce a homogeneous mixture, and may include blades that can move in planetary motion.

[0103] In one embodiment, the planetary mixer may include one or more planetary blades and one or more high-speed dispersion blades. As a specific example, the planetary mixer may include one or more planetary blades and one or more high-speed dispersion blades.

[0104] The planetary blades and high-speed dispersion blades rotate continuously about their axes, and the rotational speed may be expressed in units of rotations per minute (rpm).

[0105] In one embodiment, the planetary mixer may include a first blade and a second blade having different rotation axes. For example, the first blade may be a low-speed blade, and the second blade may be a high-speed blade. Here, low speed and high speed refer to the relative rotation speeds of the first blade and the second blade. As a specific example, the first blade may be an open blade, and the second blade may be a Despa blade.

[0106] The rotation speed of the first blade may be, for example, 10 rpm to 100 rpm, 10 rpm to 60 rpm, or 30 rpm to 70 rpm, and the rotation speed of the second blade may be, for example, 100 rpm to 2000 rpm, 100 rpm to 1000 rpm, 300 rpm to 1700 rpm, or 500 rpm to 1700 rpm.

[0107] When the functional material is mixed with the solvent, the rotation speed of the first blade may be 10 to 60 rpm, 20 to 50 rpm, or 30 to 40 rpm, and the rotation speed of the second blade may be 300 to 1700 rpm, 600 to 1000 rpm, or 700 to 800 rpm. Mixing the solvent and functional material in this manner produces a solvent mixture in which the binder, dispersant, or a combination thereof is uniformly dispersed, making it easier to mix the aerogel in the subsequent step.

[0108] When mixing the solvent mixture and the aerogel powder, the rotation speed of the first blade of the mixer may be 30 rpm to 70 rpm, 40 rpm to 70 rpm, or 60 rpm to 70 rpm, and the rotation speed of the second blade may be 500 rpm to 1700 rpm, 600 rpm to 1600 rpm, or 800 rpm to 1500 rpm. By adding the aerogel powder to the solvent mixture and mixing it as described above, it is possible to prevent the aerogel powder from agglomerating with each other and induce uniform dispersion.

[0109] When mixing the aerogel mixture and the fibrous support, the rotation speed of the first blade of the mixer may be 10 rpm to 60 rpm, 20 rpm to 50 rpm, or 30 rpm to 40 rpm, and the rotation speed of the second blade may be 300 rpm to 1700 rpm, 400 rpm to 1500 rpm, or 800 rpm to 1200 rpm. Mixing the aerogel mixture and the fibrous support in this manner removes air bubbles from the composition, adjusts the viscosity, and facilitates dispersion of the fibrous support among the uniformly dispersed aerogel, allowing the aerogel to exist in a form in which it surrounds the fibrous support in the composition. The presence of a binder between the aerogel and the fibrous support can improve the bonding strength between the aerogel and the fibrous support.

[0110] In one embodiment, the aerogel layer may be formed in a single layer structure or a multi-layer structure. When the aerogel layer is formed in a multi-layer structure, the aerogel layer may be formed in a structure of 2 to 10 layers, 2 to 7 layers, or 2 to 5 layers.

[0111] The aerogel layer can be formed by a conventional method such as extrusion, coating, or casting of the aerogel composition.

[0112] By forming an aerogel layer using a method according to an embodiment, the durability of the battery insulation sheet is improved in addition to the thermal insulation properties, and dust generation due to the aerogel falling off during manufacturing or installation of the battery insulation sheet inside a device can be prevented.

[0113] In one embodiment, the step of forming a coating layer to cover two or more surfaces of the entire surface of the aerogel layer may be performed by dipping the aerogel layer into a coating layer forming liquid.

[0114] The coating layer forming solution may include a flexible polymer, or a flexible polymer and a flame retardant, the details of which are as described above.

[0115] When the aerogel layer is dipped into the coating layer forming liquid, the coating layer forming liquid may be dispersed or dissolved in an appropriate solvent. In this case, the viscosity can be controlled to form a uniform coating layer.

[0116] In one embodiment, the aerogel layer may be dipped in a coating layer forming solution and then dried at a temperature equal to or higher than the boiling point of the solvent, thereby producing an insulating sheet for a battery according to one embodiment.

[0117] In one embodiment, the method may further include a step of crosslinking the aerogel layer after dipping it in the coating layer forming solution, which may improve the cohesive strength between the aerogel layer and the coating layer.

[0118] The crosslinking method is not particularly limited, and may be, for example, thermal crosslinking, ultraviolet (UV) crosslinking, or the like.

[0119] The thermal crosslinking may be carried out at a temperature of 25° C. to 150° C., and the reaction time may be 10 seconds to 30 minutes.

[0120] The ultraviolet crosslinking may be carried out by irradiating with UV light for 10 seconds to 5 minutes.

[0121] During the UV crosslinking, the coating layer forming solution may further include a crosslinking agent.

[0122] The crosslinking agent is not particularly limited and may be, for example, one or more compounds selected from the group consisting of polyfunctional acrylate compounds, isocyanate compounds, epoxy compounds, aziridine compounds, and metal chelate compounds.

[0123] The polyfunctional acrylate compound may be, for example, one or more compounds selected from the group consisting of pentaerythritol tri / tetraacrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, ethylene glycol diacrylate, and hexamethylene diacrylate.

[0124] The isocyanate compound may be, for example, one or more compounds selected from the group consisting of toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoform diisocyanate, tetramethylxylene diisocyanate, and naphthalene diisocyanate.

[0125] The epoxy compound may be, for example, one or more selected from the group consisting of ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N,N,N',N'-tetraglycidylethylenediamine, and glycerin diglycidyl ether.

[0126] The aziridine compound may be, for example, one or more compounds selected from the group consisting of N,N'-toluene-2,4-bis(1-aziridinecarboxylate), N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxylate), triethylenemelamine, bisisoprothaloyl-1-(2-methylaziridine), and tri-1-aziridinylphosphine oxide.

[0127] The metal chelate compound may include, for example, a compound in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, or vanadium is coordinated with acetylacetone or ethyl acetoacetate.

[0128] When ultraviolet (UV) crosslinking is performed, a photoinitiator may be further included.

[0129] The photoinitiator is not particularly limited and may be, for example, one or more selected from the group consisting of benzophenone, acetophenone, chloroacetophenone, diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, beta-chloroanthraquinone, thioxanthone, and 2-ethylanthraquinone.

[0130] In one embodiment, the insulating sheet for a battery may have a substrate disposed on one or both sides, where one side refers to the upper or lower side of the insulating sheet for a battery on which a coating layer is formed, and both sides refer to the upper and lower sides of the insulating sheet for a battery.

[0131] The substrate may be made of various materials, such as a resin, a metal, an inorganic material other than a metal, or a composite thereof, and is not limited to a particular type. The form of the substrate may be a film, a thin film, a sheet, or the like, and is not particularly limited to a particular form.

[0132] The resin may include, for example, one or more selected from the group consisting of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide.

[0133] The metal may include, for example, one or more selected from the group consisting of copper, nickel, cobalt, iron, chromium, vanadium, palladium, ruthenium, rhodium, molybdenum, tungsten, iridium, silver, gold, and platinum. When using a substrate made of such a metal material, the substrate may be subjected to corrosion prevention treatment, insulation treatment, etc., as necessary.

[0134] The inorganic material may include one or more selected from the group consisting of calcium carbonate (CaCO3), talc, and mica.

[0135] As a specific example, the substrate may include an inorganic material, and more specifically, it may include mica, which can improve the heat insulating properties and durability of the heat insulating sheet.

[0136] A battery module according to an embodiment may include a plurality of cells, and the battery insulation sheets disposed between the plurality of cells, respectively.

[0137] The cell may be a secondary battery cell. The secondary battery may be, for example, a lithium secondary battery. The lithium secondary battery may be manufactured in various forms, such as a lithium ion battery, an all-solid-state battery, or a lithium metal battery. For example, the lithium secondary battery may have a structure in which a positive electrode plate and a negative electrode plate, each coated with a positive electrode active material and a negative electrode active material, are arranged with a separator sandwiched therebetween, and the positive electrode plate and negative electrode active material are sealed together with an electrolyte in a battery case to form a secondary battery cell. Depending on the shape of the battery case, the battery case may be classified as a cylindrical type, a prismatic type, or a pouch type, and a plurality of secondary battery cells may be connected in series or parallel to form a battery module.

[0138] Such secondary batteries require high stability. However, for example, if they are overcharged, decomposition reactions of the positive electrode active material or electrolyte and other side reactions may occur, and these reactions may release heat, eventually leading to an explosion of the secondary battery cell.

[0139] In this regard, in the present invention, by placing an insulating sheet between each of the cells, which includes a coating layer formed to cover part or all of the surface, the sheet not only has excellent insulating properties, but also fire resistance and flame retardancy or non-combustibility, and can suppress the spread of heat and flame to adjacent cells due to thermal runaway of the cells.

[0140] FIG. 1 is a schematic diagram showing a plurality of cells and a heat insulating sheet for a battery disposed between the cells.

[0141] 1, a battery insulation sheet 100 according to an embodiment may be disposed between the cells 200 in a battery module including a plurality of cells 200. By forming the battery insulation sheet 100 according to an embodiment between the cells 200, a flame is blocked first when the battery overheats, minimizing the spread of the flame to other cells, thereby providing a battery module with improved safety, and further providing a battery pack including the battery module.

[0142] FIG. 2 is a schematic diagram showing the structure of a heat insulating sheet for a battery according to one embodiment.

[0143] Referring to FIG. 2, the battery insulation sheet 100 may be formed to have a structure including an aerogel layer 110 and a coating layer 120 formed on the entire surface of the aerogel layer, including the upper surface, the lower surface, and the edge side surfaces between the upper and lower surfaces.

[0144] Specific examples of the present invention will be presented below. However, the examples described below are merely for the purpose of specifically illustrating or explaining the present invention, and the present invention should not be limited thereto. Furthermore, since the contents not described here can be sufficiently inferred by those skilled in the art, a description thereof will be omitted.

[0145] (Manufacture of heat insulating sheets for batteries) Example 1 1. Aerogel Layer Fabrication Polyvinyl alcohol (Sigma Aldrich, Poly(vinyl alcohol)) was added as a binder to ultrapure water as a solvent, and then mixed with an open blade at 30 rpm and a despa blade at 700 rpm to produce a solvent mixture. 2An aerogel mixture was prepared by adding aerogel (1 / g) and mixing with an open blade at 70 rpm and a Despa blade at 1500 rpm. Glass wool was added to the aerogel mixture and mixed with an open blade at 30 rpm and a Despa blade at 1200 rpm to prepare an aerogel composition. A planetary mixer (DIENTEK, PT-005) was used for mixing.

[0146] The solid content of the prepared aerogel composition was confirmed to be 50 wt % aerogel, 40 wt % glass wool, and 10 wt % polyvinyl alcohol.

[0147] The prepared aerogel composition was used to form an aerogel layer.

[0148] 2. Manufacture of heat insulating sheets for batteries The aerogel layer was then dipped into a coating solution to form a coating layer over the entire surface of the aerogel layer. The coating solution was made with a composition of 94.8 wt% polyurethane (Shenzhen Jiian Chemical, PU solution), 4 wt% ammonium phosphate (Merck, Ammonium Phosphate) and 1.2 wt% dipentaerythritol (Merck) as flame retardants.

[0149] An aerogel layer was dipped in the coating layer-forming solution and then dried to produce an insulating sheet for a battery having a coating layer formed on the entire surface of the aerogel layer. The total thickness of the insulating sheet for a battery was 3 mm, the thickness of the aerogel layer was 2.7 mm, and it was confirmed that the thickness of the coating layer was 0.15 mm on each of the top, bottom, and edge of the aerogel layer.

[0150] Example 2 The coating layer was prepared in the same manner as in Example 1, except that a coating layer-forming solution having a composition of 94.8 wt% of silicone elastomer (Gelest, EXsil 100) and 4 wt% of ammonium phosphate (Merck, Ammonium Phosphate) and 1.2 wt% of dipentaerythritol (Merck, Dipentaerythritol) as flame retardants was used.

[0151] Example 3 The insulation sheet for a battery was manufactured in the same manner as in Example 1, except that the thicknesses of the aerogel layer and the coating layer were adjusted. Specifically, it was confirmed that the total thickness of the manufactured insulation sheet for a battery was 3 mm, the thickness of the aerogel layer was 2.6 mm, and the thickness of the coating layer was 0.2 mm.

[0152] Example 4 The insulation sheet was manufactured in the same manner as in Example 1, except that the thicknesses of the aerogel layer and the coating layer were adjusted. Specifically, it was confirmed that the total thickness of the manufactured insulation sheet for a battery was 3 mm, the thickness of the aerogel layer was 2.4 mm, and the thickness of the coating layer was 0.3 mm.

[0153] Example 5 The same method as in Example 1 was used to prepare the coating layer, except that a coating layer-forming solution containing 80 wt% polyurethane (PU solution, Shenzhen Jiian Chemical), 15 wt% ammonium phosphate (Ammonium Phosphate, Merck) and 5 wt% dipentaerythritol (Dipentaerythritol, Merck) as flame retardants was used.

[0154] Example 6 The same method as in Example 1 was used to prepare the coating layer, except that a coating layer-forming solution containing 97.6 wt% polyurethane (PU solution, Shenzhen Jiian Chemical), 1.8 wt% ammonium phosphate (Ammonium Phosphate, Merck) and 0.6 wt% dipentaerythritol (Dipentaerythritol, Merck) as flame retardants was used.

[0155] Example 7 The same method as in Example 1 was used to prepare the coating layer, except that a coating layer-forming solution containing 94.8 wt% polyurethane (PU solution, Shenzhen Jiian Chemical), 4.0 wt% ammonium dihydrogen phosphate as a flame retardant, and 1.2 wt% dipentaerythritol (Merck) was used.

[0156] Example 8 The same method as in Example 1 was used to prepare the coating layer, except that a coating layer-forming solution containing 95 wt% polyurethane (Shenzhen Jiian Chemical, PU solution) and 5 wt% ammonium hydroxide (Merck, Aluminum hydroxide) as a flame retardant was used.

[0157] Comparative Example 1 The aerogel layer was prepared in the same manner as in Example 1, except that no coating layer was formed on the surface of the aerogel layer. It was confirmed that the aerogel layer had a total thickness of 3 mm in the prepared insulating sheet for a battery.

[0158] Comparative Example 2 The coating layer was prepared in the same manner as in Example 1, except that a coating layer-forming solution containing 100 wt % polyurethane (PU solution, Shenzhen Jiian Chemical) was used.

[0159] Comparative Example 3 The coating layer was prepared in the same manner as in Example 1, except that a coating layer-forming solution having a composition of 84.8 wt% polyurethane (PU solution, Shenzhen Jiian Chemical), 4 wt% ammonium phosphate (Ammonium Phosphate, Merck) and 1.2 wt% dipentaerythritol (Dipentaerythritol, Merck) as flame retardants, and 10 wt% fumed silica as a filler was used.

[0160] Comparative Example 4 The fabrication method was the same as in Example 1, except that the coating layer was formed only on the upper surface of the aerogel layer, and the aerogel layer was formed to a thickness of 2.7 mm and the coating layer was formed to a thickness of 0.3 mm.

[0161] FIG. 3 is a schematic diagram showing the structure of the heat insulating sheet for a battery according to Comparative Example 4. As shown in FIG.

[0162] Referring to FIG. 3, the heat insulating sheet for a battery 100 is formed to have a structure including an aerogel layer 110 and a coating layer 120 formed on the upper surface of the aerogel layer.

[0163] Comparative Example 5 The fabrication method was the same as in Example 1, except that the coating layer was formed only on the edge side between the upper and lower surfaces of the aerogel layer, and the aerogel layer was formed to a thickness of 3 mm.

[0164] FIG. 4 is a schematic diagram showing the structure of the heat insulating sheet for a battery according to Comparative Example 5. As shown in FIG.

[0165] Referring to FIG. 4, the battery insulation sheet 100 is formed to have a structure including an aerogel layer 110 and a coating layer 120 formed on the edge side between the upper and lower surfaces of the aerogel layer.

[0166] (Experimental example) Experimental example 1: Evaluation of coating layer properties The elastic modulus of the coating layer of the heat insulating sheets for batteries manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 was evaluated.

[0167] Specifically, the elastic modulus was measured according to ASTM D882, and the measurement results are shown in Tables 1 and 2 below.

[0168] Experimental example 2: Evaluation of the physical properties of heat insulating sheets for batteries 1.Insulation evaluation The heat insulating properties of the heat insulating sheets manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 were evaluated.

[0169] Specifically, each insulation sheet was placed between a pair of opposing 1T thick aluminum plates, which were then placed on a heat press. The upper plate of the heat press was heated to 350°C, while the lower plate of the heat press was not heated and maintained at the starting temperature of 40°C. A pressure of 20 kN was then applied to the lower plate of the heat press, and the maximum temperature of the lower plate of the heat press was measured after 11 minutes. The results are shown in Tables 1 and 2 below.

[0170] 2. Compressibility evaluation The heat insulating sheets produced in Examples 1 to 8 and Comparative Examples 1 to 5 were produced to a size of 140 mm x 100 mm, and used to evaluate compression performance.

[0171] Specifically, the thickness ratio when a load of 5kN was applied was measured based on the thickness when a load of 40kN was applied using UTM equipment, and is shown in Tables 1 and 2 below.

[0172] 3.Flame retardancy evaluation The heat insulating sheets manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 were used to evaluate flame retardancy.

[0173] Specifically, the flame retardancy was evaluated according to the UL-94V flame retardancy rating test method (UL94V Test (Vertical Burning Test)) into grades of V-0, V-1, and V-2, and the results are shown in Tables 1 and 2 below.

[0174] 4. Dustiness evaluation The heat insulating sheets manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 were used to evaluate dust resistance.

[0175] The dust characteristics were evaluated by measuring weight loss through vibration evaluation. Specifically, a 140mm x 100mm test piece was subjected to 30Hz vibration for 1 hour using vibration evaluation equipment, and then the weight loss was measured. The results are shown in Tables 1 and 2 below. A weight loss of less than 1% was evaluated as good, and a weight loss of 1% or more was evaluated as bad.

[0176] [Table 1]

[0177] [Table 2]

[0178] In Table 2 above, NG means that the evaluation results are below V-2 grade.

[0179] Referring to Tables 1 and 2 above, it can be seen that, compared to Examples 1 to 8, Comparative Example 1 has high thermal insulation properties due to the presence of only an aerogel layer with a thickness of 3 mm, but the absence of a coating layer reduces compressibility and dust resistance. In Comparative Example 2, the coating layer does not contain a flame retardant, so flame retardancy cannot be ensured. In Comparative Example 3, the coating layer contains 10 wt% filler, which significantly reduces the elastic modulus of the coating layer and the compressibility of the heat insulating sheet. In Comparative Example 4, coating layers are formed only on the top and bottom surfaces of the aerogel layer, which reduces dust resistance. In Comparative Example 5, coating layers are formed only on the edge sides of the aerogel layer, which reduces compressibility.

[0180] Therefore, it was confirmed that the use of an insulating sheet for a battery according to an embodiment of the present invention provides excellent heat insulation, compressibility, flame retardancy, and dust resistance.

[0181] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and it is natural that these modifications also fall within the scope of the present invention. [Explanation of symbols]

[0182] 100 Battery insulation sheet 110 Aerogel layer 120 coating layers 200 cells

Claims

1. an aerogel layer containing aerogel; a coating layer covering the entire surface of the aerogel layer; the coating layer includes a flexible polymer and a flame retardant dispersed in the flexible polymer; The coating layer has an elastic modulus of 8 MPa or less as measured by ASTM D882.

2. The aerogel has a BET specific surface area of ​​500 m 2 / g to 1,000m 2 The insulating sheet for a battery according to claim 1, wherein the elastic modulus is 1 / g.

3. The battery insulating sheet according to claim 1 , wherein the aerogel layer further comprises a fibrous support and a functional material comprising a binder, a dispersant, or a combination thereof.

4. The battery insulating sheet according to claim 3 , wherein the fibrous support comprises at least one fiber selected from the group consisting of natural fibers, silica fibers, glass fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

5. The battery insulating sheet according to claim 3 , wherein the binder is a water-based polymer binder.

6. The battery insulating sheet according to claim 3 , wherein the dispersant is at least one selected from the group consisting of a surfactant, a silane coupling agent, and a phosphate salt.

7. 4. The battery insulating sheet according to claim 3, wherein the aerogel layer contains, relative to the total amount of the aerogel layer, 10% by weight to 90% by weight of the aerogel, 5% by weight to 70% by weight of the fibrous support, and 0.5% by weight to 20% by weight of the functional material.

8. The battery insulating sheet according to claim 1 , wherein the flexible polymer is at least one selected from the group consisting of a fluorine-based polymer, a polyurethane-based polymer, a polyolefin-based polymer, and a silicone-based polymer.

9. 2. The battery insulating sheet according to claim 1, wherein the flame retardant is at least one selected from the group consisting of inorganic flame retardants, phosphorus-based flame retardants, nitrogen compound-based flame retardants, silicon-based flame retardants, melamine-based flame retardants, halogen-based flame retardants, and polyhydric alcohol-based flame retardants.

10. The battery insulating sheet according to claim 1 , wherein the flame retardant comprises a phosphorus-based flame retardant and a polyhydric alcohol-based flame retardant.

11. The battery insulating sheet according to claim 10, wherein the flame retardant comprises a phosphorus-based flame retardant and a polyhydric alcohol-based flame retardant in a weight ratio of 1:0.1 to 1:0.

5.

12. The battery insulating sheet according to claim 1, wherein the content of the flame retardant is 1% by weight to 25% by weight based on the total weight of the coating layer.

13. The battery insulating sheet according to claim 1 , wherein the coating layer does not contain a filler.

14. The battery insulating sheet according to claim 1 , wherein the thickness of the coating layer is 20% or less of the total thickness of the battery insulating sheet.

15. the flexible polymer is at least one selected from the group consisting of polyurethane-based polymers and silicone-based polymers; The battery insulating sheet according to claim 1 , wherein the flame retardant is at least one selected from the group consisting of polyhydric alcohol-based flame retardants and phosphorus-based flame retardants.

16. forming an aerogel layer comprising an aerogel; forming a coating layer to cover the entire surface of the aerogel layer; the coating layer includes a flexible polymer and a flame retardant dispersed in the flexible polymer; The method for manufacturing a heat insulating sheet for a battery, wherein the coating layer has an elastic modulus of 8 MPa or less as measured by ASTM D882.

17. A plurality of cells; and the heat insulating sheet according to any one of claims 1 to 15, disposed between each of the plurality of cells.

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