Insulating sheet for battery, method of manufacturing same, and battery module including insulating sheet

Abstract

The invention relates to an insulating sheet for a battery, a method of manufacturing the same, and a battery module including the insulating sheet. Embodiments include an insulating sheet for a battery, the insulating sheet including an aerogel layer comprising an aerogel and a coating layer configured to cover substantially the entire surface of the aerogel layer. The coating includes a flexible polymer and a flame retardant dispersed in the flexible polymer, and the coating has an elastic modulus of about 8 MPa or less as measured according to ASTM D882. Embodiments also include a method of manufacturing the insulating sheet and a battery module including the insulating sheet.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0078078 filed on June 19, 2023 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Example embodiments relate to an insulation sheet for a battery, a method of manufacturing the same, and a battery module including the insulation sheet. Background Art

[0004] Secondary batteries are power storage systems that convert electrical energy into chemical energy, store chemical energy, and provide high energy density. Compared with non-rechargeable primary batteries, secondary batteries are rechargeable and are generally widely used in information technology (IT) devices, such as smart phones, mobile phones, laptop computers, and tablet computers. At present, people are increasingly interested in electric vehicles to reduce or prevent environmental pollution, and high-capacity secondary batteries are generally used in electric vehicles. Secondary batteries generally exhibit desired characteristics such as, for example, high density, high output, and stability.

[0005] When multiple high-capacity battery cells are included, such as in a lithium-ion secondary battery, one battery cell may overheat and may enter thermal runaway for various reasons, which may adversely affect other battery cells adjacent thereto, so it is desirable to thermally isolate adjacent battery cells from each other.

[0006] Conventionally, a plate or an insulating resin sheet is positioned between the battery cells to separate and insulate adjacent battery cells from each other. Summary of the invention

[0007] Example embodiments provide an insulating sheet for a battery, a method for manufacturing the same, and a battery module including the insulating sheet, which has desired, advantageous, or improved thermal insulation, fire resistance, and flame retardancy or non-flammability to reduce or inhibit the propagation of heat in a battery cell to battery cells adjacent thereto due to thermal runaway of the battery cell.

[0008] Example embodiments include an insulating sheet for a battery, the insulating sheet including an aerogel layer including an aerogel and a coating configured to cover substantially the entire surface of the aerogel layer, wherein the coating includes a flexible polymer and a flame retardant dispersed in the flexible polymer, and an elastic modulus of the coating measured according to ASTM D882 is about 8 MPa or less.

[0009] Aerogels can have a thermal conductivity of about 500 m 2 / g~1,000m 2 The Brunauer, Emmett and Teller (BET) specific surface area is in the range of / g.

[0010] The aerogel layer may further include a fiber support and a functional material, wherein the functional material includes a binder, a dispersant, or a combination thereof.

[0011] The fibrous support may include at least one of natural fibers, silica fibers, glass fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

[0012] The binder may include a water-based polymer binder.

[0013] The dispersant may be or include at least one of a surfactant, a silane coupling agent and a phosphate salt.

[0014] The aerogel may be included in a range of about 10 wt % to 90 wt %, the fibrous support may be included in a range of about 5 wt % to 70 wt %, and the functional material may be included in a range of about 0.5 wt % to 20 wt % based on the total amount of the aerogel layer.

[0015] The flexible polymer may be at least one of a fluorinated polymer, a polyurethane-based polymer, a polyolefin-based polymer, and a silicone-based polymer.

[0016] The flame retardant may be at least one of an inorganic flame retardant, a phosphorus flame retardant, a nitrogen compound flame retardant, a silicone flame retardant, a melamine flame retardant, a halogen flame retardant, and a polyol flame retardant.

[0017] The flame retardant may include at least one of a phosphorus-based flame retardant and a polyol-based flame retardant.

[0018] The flame retardant may include a phosphorus-based flame retardant and a polyol-based flame retardant in a weight ratio ranging from about 1:0.1 to 1:0.5.

[0019] The content of the flame retardant may be in the range of about 1 wt % to 25 wt % based on the total amount of the coating layer.

[0020] The coating may not include fillers.

[0021] The thickness of the coating layer may be about 20% or less of the total thickness of the insulating sheet for a battery.

[0022] The flexible polymer may be or include at least one of a polyurethane-based polymer and a silicone-based polymer, and the flame retardant may be at least one of a polyol-based flame retardant and a phosphorus-based flame retardant.

[0023] Another example embodiment includes a method of manufacturing an insulating sheet for a battery, the method including forming an aerogel layer including an aerogel and forming a coating to cover substantially the entire surface of the aerogel layer, wherein the coating includes a flexible polymer and a flame retardant dispersed in the flexible polymer, and an elastic modulus of the coating measured according to ASTM D882 is about 8 MPa or less.

[0024] Further example embodiments include a battery module including a plurality of battery cells and an insulating sheet between the plurality of battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The attached drawings incorporated in this specification illustrate example embodiments, and are used in conjunction with the following detailed description of example embodiments to further illustrate the technical idea of ​​the present disclosure, and the present disclosure is not to be construed as being limited to the contents shown in these drawings. In the drawings:

[0026] Figure 1 is a schematic diagram showing an insulating sheet for a battery according to an example embodiment formed between a plurality of battery cells;

[0027] Figure 2 To show the basis Figure 1 A schematic diagram of a cross-sectional structure of an insulating sheet for a battery according to an exemplary embodiment of the present invention; and

[0028] Figure 3 and Figure 4 Schematic diagrams each showing a cross-sectional structure of an insulating sheet according to a comparative example. DETAILED DESCRIPTION

[0029] Hereinafter, example embodiments will be described in detail so that those skilled in the art can easily implement the example embodiments. However, example embodiments may be implemented in many different forms and are not limited to the example embodiments described herein.

[0030] When the term "about" or "substantially" is used in conjunction with a numerical value in this specification, it is intended that the relevant numerical value includes a tolerance of ±10% around the numerical value. Moreover, when percentages are mentioned in this specification, it is intended that those percentages are based on concentration or weight, such as concentration percentage or weight percentage. When a range is indicated, the range includes all values ​​therebetween, such as increments of 0.1%.

[0031] Insulation, a material that retards or blocks the flow of heat from higher temperatures to lower temperatures, is used not only in refrigerators, cold stores and buildings, but also in a variety of other industries, including aircraft, electronics and automobile industries.

[0032] The insulating material desirably and advantageously has sufficient thermal insulation through low thermal conductivity and mechanical strength to maintain thermal insulation over time.

[0033] Aerogel, as a transparent or translucent advanced material with a nanoporous structure, exhibits substantially low density and low thermal conductivity, so aerogel is highly desired as an insulating material and is considered to be a highly efficient super insulating material that can be used in various industrial applications.

[0034] Important advantages of aerogels are that aerogels have lower thermal conductivity than conventional organic insulating materials such as, for example, polystyrene foam, and aerogels can solve or overcome key weaknesses of organic insulating materials, such as, for example, vulnerability to fire and generation of harmful gases during fire.

[0035] An insulating sheet for a battery according to example embodiments may include an aerogel layer including an aerogel and a coating layer configured to cover substantially the entire surface of the aerogel layer, wherein the coating layer may include a flexible polymer and a flame retardant dispersed in the flexible polymer, and the elastic modulus of the coating layer measured according to ASTM D882 may be about 8 MPa or less.

[0036] The insulating sheet for a battery having the above structure may have desired, advantageous or improved thermal insulation, fire resistance and flame retardancy or non-flammability, thereby reducing or inhibiting the propagation of heat and flame in one battery cell to a battery cell adjacent thereto due to thermal runaway of the battery cell. The insulating sheet for a battery may have desired, advantageous or improved compressibility, mechanical strength and dimensional stability, and may reduce or prevent the aerogel layer from falling off due to external impact, thereby improving processability and reducing or preventing instrument contamination.

[0037] In an example embodiment, the aerogel may have a 2 / g~1,000m 2 The aerogel may have a BET surface area in the range of about 500 m / g. 2 / g~950m 2 / g, 550m 2 / g~950m 2 / g or 600m 2 / g~900m 2 Because the aerogel having a BET specific surface area value within the above range is included, diffusion of aerogel particles can be reduced or prevented, and thermal insulation can be improved.

[0038] The particle size of the aerogel may be in the range of about 5 μm to 200 μm, 10 μm to 100 μm, or 20 μm to 60 μm. Since the aerogel having the particle size in the above range is included, thermal insulation may be improved, thereby delaying heat propagation between a plurality of battery cells.

[0039] The content of the aerogel may be in the range of about 10 wt% to 90 wt%, 30 wt% to 70 wt%, or 40 wt% to 60 wt% based on the total amount of the aerogel layer. When the aerogel layer including the aerogel within the above range is included, thermal insulation of an insulating sheet for a battery may be desirable or advantageous.

[0040] In example embodiments, the aerogel layer may further include a fiber support and a functional material including a binder, a dispersant, or a combination thereof.

[0041] The fibrous support may be included in the aerogel layer, whereby the durability of an insulating sheet for a battery formed using the fibrous support may be improved.

[0042] The fibrous support may include fibers used as a support made of or including common insulating materials. For example, the fibrous support may be or include at least one of natural fibers, silica fibers, glass fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers. As an example, the fibrous support may include, but is not limited to, glass fibers. As an example, the glass fibers may include, but are not limited to, glass wool.

[0043] The natural fiber may be or include, for example, at least one of hemp, jute, flax, coir, kenaf, and cellulose.

[0044] The mineral fiber may include, for example, at least one of basalt, quartzite, alumina, silica, slag, and rock.

[0045] The polymer fiber may be, for example, at least one of nylon, polyimide, polyamide, polybenzimidazole, polybenzoxazole, polyamideimide, polyethylene terephthalate, polybutylene terephthalate, polyester, polyethylene (PE) and polypropylene (PP). As an example, the polymer fiber may be, but is not limited to, at least one of polyimide, polyamide and polybenzimidazole.

[0046] The fibrous support may be in the form of, for example, wool or chopped strands, but is not limited thereto.

[0047] The average particle size D50 of the fiber support may be, for example, in the range of about 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 fiber support having an average particle size in the above range, the structure of the aerogel layer may be hardened and the manufacturing cost may be reduced.

[0048] The average particle size D50 can be measured, for example, using a laser diffraction method or a scanning electron microscope (SEM), where the average particle size D50 of the particles can be defined as the particle size at 50% of the particle size distribution (the particle size corresponding to the cumulative 50% by volume of the particle size distribution).

[0049] The content of the fiber support may be in the range of about 5 wt% to 70 wt%, 25 wt% to 60 wt% or 30 wt% to 50 wt% based on the total amount of the aerogel layer. When an aerogel layer including the fiber support in the above range is used to manufacture an insulating sheet for a battery, durability may be improved.

[0050] The binder may include an aqueous polymer binder. For example, the aqueous polymer binder may be at least one of an aqueous polymer, an anionic water-soluble polymer, a cationic water-soluble polymer, and a water-dispersible polymer.

[0051] The water-based polymer may be, for example, but not limited to, at least one of polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinyl pyrrolidone.

[0052] The anionic water-soluble polymer may be a polymer having at least one functional group of carboxylic acid, sulfonic acid, sulfate, phosphate, and salts thereof. For example, the anionic water-soluble polymer may be or include a polymer having a carboxylic acid group, and may include, but is not limited to, polymaleic acid as an example.

[0053] The cationic water-soluble polymer may be a polymer having at least one functional group of amine, ammonium, phosphonium, sulfonium and salts thereof. For example, the cationic water-soluble polymer may be or include a polymer having an amine group, and may be, but not limited to, at least one of polyvinylamine and polyamine as an example.

[0054] The water-dispersible polymer may be, but is not limited to, at least one of a water-dispersible polyurethane and a water-dispersible polyester.

[0055] The binder may include a water-based polymer and a water-dispersible polymer. For example, the binder may include a water-based polymer having a binder property and a dispersible property and a water-dispersible polymer having fire resistance. As an example, the binder may include polyvinyl alcohol and a water-dispersible polyurethane.

[0056] The weight ratio of the aqueous polymer to the water-dispersible polymer may be in the range of about 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 the above range, in addition to the thermal insulation, dust formation and compressibility of the insulation sheet, the fire resistance and mechanical properties of the insulation sheet may be further improved.

[0057] The binder may be included in an amount of about 0.5-20 wt%, 2-15 wt%, or 8-15 wt% based on the total amount of the aerogel layer. An insulating sheet for a battery including an aerogel layer including the binder within the above range may have improved dusting properties.

[0058] The dispersant may be or include at least one of a surfactant, a silane coupling agent, and a phosphate salt. For example, the dispersant may include, but is 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 ester.

[0059] Further inclusion of a dispersant can further improve the dispersion of the aerogel during the manufacture of the aerogel layer, resulting in a uniform dispersion of the fibrous support and the aerogel.

[0060] The content of the dispersant may be in the range of about 0.1 wt% to 6 wt%, 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total amount of the aerogel layer. When the dispersant is included within the above range, the aerogel layer can be manufactured at a low cost and used to manufacture an insulation sheet having desired, improved or advantageous thermal insulation, uniformity, and dust formation.

[0061] In example embodiments, the binder and the dispersant may be included in a weight ratio ranging from about 1:0.001 to 1:0.67, 1:0.001 to 1:0.5, or 1:0.001 to 1:0.3. Mixing the binder and the dispersant in a weight ratio within any of the above ranges may result in aerogel being more uniformly dispersed in the aerogel layer.

[0062] In example embodiments, the fibrous support may be included in a range of about 25 wt % to 60 wt %, the aerogel may be included in a range of about 30 wt % to 70 wt %, and the binder may be included in a range of about 2 wt % to 15 wt % based on the total amount of the aerogel layer.

[0063] As an example, based on the total amount of the aerogel layer, the fiber support may be included in a range of about 30 wt% to 50 wt%, the aerogel may be included in a range of about 40 wt% to 60 wt%, and the binder may be included in a range of about 8 wt% to 15 wt%. When the aerogel layer is formed within any of the above ranges, it is possible to achieve desired, improved or advantageous thermal insulation while improving durability, and the bonding between the fiber support and the aerogel may be improved, thereby reducing or preventing dust generation.

[0064] In an example embodiment, based on the total amount of the aerogel layer, the fibrous support may be included in a range of about 25 wt % to 60 wt %, the aerogel may be included in a range of about 30 wt % to 70 wt %, the binder may be included in a range of about 2 wt % to 15 wt %, and the dispersant may be included in a range of about 0.1 wt % to 3 wt %.

[0065] As an example, based on the total amount of the aerogel layer, the fiber support may be included in a range of about 30 wt% to 50 wt%, the aerogel may be included in a range of about 40 wt% to 60 wt%, the binder may be included in a range of about 5 wt% to 10 wt%, and the dispersant may be included in a range of about 0.1 wt% to 2 wt%. When the aerogel layer is formed within the above range, desired, improved or advantageous thermal insulation may be achieved while improving durability, and the bonding between the fiber support and the aerogel may be improved, thereby reducing or preventing dust generation.

[0066] The flexible polymer included in the coating layer is not particularly limited as long as the polymer is flexible. For example, the flexible polymer may be at least one of a fluorinated polymer, a polyurethane-based polymer, a polyolefin-based polymer, and a silicone-based polymer.

[0067] The fluorinated polymer may be, for example, at least one of polytetrafluoroethylene (PTFE), soluble polytetrafluoroethylene (PFA), fluorinated ethylene propylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF) and polychlorotrifluoroethylene (PCTFE). The fluorinated polymer may be a material that is both flexible and flame retardant.

[0068] The polyurethane polymer is not particularly limited as long as the polyurethane polymer is a common polyurethane manufactured by polymerization of a polyol and a polyisocyanate. The polyol may be, for example, a common polyol for manufacturing polyurethane, and may be at least one of a polyether polyol, a polyester polyol, a polyamide polyol, a polyesteramide polyol, a polythioether polyol, a polycarbonate polyol, a polyacetal polyol, a polyolefin polyol, a polysiloxane polyol, an acrylic polyol, and a silicone polyol. The polyisocyanate may include, for example, common polyisocyanates used to make polyurethanes, and may be or include at least one 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, 1,5-naphthalene diisocyanate, trimethylhexamethylene diisocyanate, and norbornane diisocyanate.

[0069] The polyolefin-based polymer may be, for example, at least one of polyethylene, polypropylene, polybutylene, polypentene, polyvinylidene fluoride, and polymethyl methacrylate.

[0070] The silicone-based polymer may be, for example, at least one of silicone elastomer, polydimethylsiloxane, polymethylethylsiloxane, polydiethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and polyethylphenylsiloxane.

[0071] The content of the flexible polymer may be in the range of about 75 wt% to 99 wt%, 90 wt% to 97 wt% or 94 wt% to 97 wt% of the total amount of the coating. By forming a coating layer including a flame retardant in any of the above ranges on the surface of an aerogel layer having desired, improved or advantageous thermal insulation, an insulating sheet for a battery may have not only thermal insulation but also fire resistance and flame retardancy or non-flammability.

[0072] The coating layer may further include a flame retardant. The type of the flame retardant is not particularly limited, and the flame retardant may be at least one of, for example, an inorganic flame retardant, a phosphorus flame retardant, a nitrogen compound flame retardant, a silicone flame retardant, a melamine flame retardant, a halogen flame retardant, and a polyol flame retardant.

[0073] The inorganic flame retardant may include metal oxides and metal hydroxides. For example, the inorganic flame retardant may be, but is not limited to, at least one of silicon oxide, magnesium hydroxide, aluminum hydroxide, antimony oxide, sodium carbonate, zinc oxide, iron oxide, tin oxide, zinc borate, and calcium borate.

[0074] The phosphorus-based flame retardant may include a common phosphorus-containing flame retardant. For example, the phosphorus-based flame retardant may include, but is not limited to, at least one of phosphates, phosphonates, phosphinates, phosphine oxides, phosphazenes, and ammonium salts thereof.

[0075] The phosphorus flame retardant may include ammonium phosphate or ammonium phosphate having two or more hydroxyl groups at the end of the functional group. The use of a phosphorus flame retardant having a multifunctional hydroxyl group may provide desired, improved or advantageous flame retardancy. As an example, the phosphorus flame retardant may include, but is not limited to, ammonium phosphate or diammonium phosphate.

[0076] The nitrogen compound-based flame retardant may be, but is not limited to, at least one of aliphatic amine compounds, aromatic amine compounds, nitrogen-containing bicyclic compounds, cyanide compounds, ammonium hydroxide, aliphatic amides, aromatic amides, urea, and thiourea.

[0077] Silicone flame retardants may be silicone resins and silicone oils. Silicone resins may include resins having an RSiO structure, wherein R may indicate an alkyl group (such as a methyl group, an ethyl group, or a propyl group) having a carbon number of 1 to 10, an aryl group, or a substituent in which at least one hydrogen in the alkyl group and the aryl group is replaced by a vinyl group. Silicone oil may be, but is not limited to, at least one of polydimethylsiloxane and modified polydimethylsiloxane, wherein at least one methyl group in the side chain or at the end of the polydimethylsiloxane in the modified polydimethylsiloxane is modified by at least one of hydrogen, an alkyl group (except a methyl group), a cyclohexyl group, a phenyl group, a benzyl group, an epoxy group, a polyether group, a carboxyl group, a mercapto group, a chloroalkyl group, an alkyl alcohol ester group, an alcohol group, an allyl group, a vinyl group, and a trifluoromethyl group.

[0078] The melamine-based flame retardant may be, but is not limited to, at least one of melamine phosphate, di(melamine) phosphate, melamine pyrophosphate and melamine cyanurate.

[0079] Any halogen compound that can be used as a flame retardant can be used as the halogen flame retardant without limitation. For example, the halogen flame retardant can be, but is not limited to, at least one of decabromodiphenyl ether, decabromodiphenyl ethane, tetrabromobisphenol A, tetrabromobisphenol A epoxy oligomer, octabromotrimethylphenyl indane, ethylene-bis-tetrabromophthalimide, tris(tribromophenol)triazine, and brominated polystyrene.

[0080] The polyol flame retardant may be, for example, at least one of pentaerythritol, dipentaerythritol, trimethylolpropane and ethylene glycol. As an example, the polyol flame retardant may be dipentaerythritol.

[0081] The flame retardant may include a phosphorus-based flame retardant and a polyol-based flame retardant, in which case flame retardancy may be achieved without releasing harmful substances.

[0082] The flame retardant may include a phosphorus-based flame retardant and a polyol-based flame retardant in a weight ratio in the range of about 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 1:0.25. When the phosphorus-based flame retardant and the polyol-based flame retardant are mixed within the above range, the elastic modulus of the coating layer may be desired, improved, or advantageous, and the flame retardancy of the insulating sheet may be improved.

[0083] The content of the flame retardant may be in the range of about 1 wt% to 25 wt%, 3 wt% to 10 wt% or 3 wt% to 6 wt% based on the total amount of the coating. By forming a coating including a flame retardant in any of the above ranges on the surface of an aerogel layer having desired, improved or advantageous thermal insulation, an insulating sheet for a battery may have not only thermal insulation but also fire resistance and flame retardancy or non-flammability.

[0084] The coating may not include a filler. The filler may be, but is not limited to, at least one of fumed silica, diatomaceous earth, halloysite, carbon nanotubes, perlite, silicon dioxide, aluminum oxide, barium sulfate, mud, 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.

[0085] The aerogel layer may be a hexahedron having an upper surface, a lower surface, and a boundary side surface between the upper surface and the lower surface, and the coating layer may be formed to cover substantially the entire surface of the aerogel layer.

[0086] As an example, the coating may cover substantially the entire surface of the aerogel layer including the upper surface, the lower surface and the boundary side surface of the aerogel layer. An insulating sheet for a battery having a coating formed to cover substantially the entire surface of the aerogel layer as described above may be disposed between a plurality of battery cells, wherein the upper surface and the lower surface of the insulating sheet for a battery may respectively face a plurality of battery cells disposed on opposite side surfaces of the insulating sheet. A coating having flame retardancy may be formed on substantially the entire surface of the insulating sheet for a battery, which may reduce or prevent the burning of the insulating sheet, and may hinder or block the flame in the event of thermal runaway of one battery cell, thereby reducing or inhibiting the spread of the flame to the battery cell adjacent thereto, and effectively reducing or preventing the spread of the flame in a battery module having a plurality of battery cells.

[0087] The thickness of the coating layer may be in the range of about 20% or less, 1% to 20%, 5% to 17%, or 8% to 12% of the total thickness of the insulating sheet for the battery. By forming the coating layer to have a thickness in any of the above ranges, the insulating sheet for the battery may have desired, improved, or advantageous thermal insulation and flame retardancy or non-flammability.

[0088] The coating may include a flexible polymer and a flame retardant dispersed in the flexible polymer, wherein the flexible polymer may be at least one of a polyurethane-based polymer and a silicone-based polymer, and the flame retardant may be at least one of a polyol-based flame retardant and a phosphorus-based flame retardant. In this case, the shedding and diffusion of the aerogel layer that may be caused by external impact may be hindered or prevented, processability may be improved, contamination of instruments may be reduced or prevented, and desired, improved or advantageous thermal insulation and flame retardancy or non-flammability may be achieved.

[0089] In example embodiments, the elastic modulus of the coating measured according to ASTM D882 may be about 8 MPa or less. For example, the elastic modulus of the coating measured according to ASTM D882 may be in the range of about 1 MPa to 8 MPa, 3 MPa to 7 MPa, or 3 MPa to 5 MPa.

[0090] A method of manufacturing an insulating sheet for a battery according to example embodiments may include forming an aerogel layer including an aerogel and forming a coating layer to cover substantially an entire surface of the aerogel layer, wherein the coating layer may include a flexible polymer and a flame retardant dispersed in the flexible polymer, and an elastic modulus of the coating layer measured according to ASTM D882 may be about 8 MPa or less.

[0091] In example embodiments, forming the aerogel layer may include mixing a solvent with a functional material including a binder, a dispersant, or a combination thereof to produce a solvent mixture, mixing the solvent mixture with an aerogel to produce an aerogel mixture, and mixing the aerogel mixture with a fiber support to produce an aerogel composition.

[0092] When the solvent is mixed with the functional material to produce a solvent mixture, the solvent may be mixed with the binder, or the solvent may be mixed with the binder and the dispersant.

[0093] The solvent may be at least one of a polar solvent and a non-polar solvent.

[0094] The polar solvent may be at least one of water and an alcohol solvent.

[0095] The water may be, for example, at least one of purified water and deionized water.

[0096] The alcohol solvent may be, for example but not limited to, at least one of methanol, ethanol, propanol, pentanol, butanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol and glycerol.

[0097] The non-polar solvent may include a hydrocarbon solvent. For example, the hydrocarbon solvent may be at least one of hexane, pentane, heptane, toluene and benzene, and may be, but not limited to, an alkane solvent (such as hexane) or a mixture including an alkane solvent.

[0098] 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, water may not be satisfactorily mixed with the aerogel because the aerogel is hydrophobic. In an example embodiment, the aerogel can be uniformly dispersed by controlling the design of the mixing process, the mixing conditions, the addition of a binder and a dispersant, and the amount of the binder and the dispersant. This uniform dispersion of the aerogel in the composition can form an insulating sheet for a battery with a thin thickness having desired or improved thermal insulation, durability, and dust formation without using a large amount of a binder.

[0099] The solvent may be included such that the weight ratio of the solvent to the total amount of solids in the aerogel composition is in the range of about 1:1 to 1:90. For example, the weight ratio of the solvent to the total amount of solids in the aerogel composition may be in the range of about 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 amount of solids in the aerogel composition within the above range, dispersibility, coatability, and phase stability may be compatible.

[0100] The detailed description of the binder and dispersant may be similar or the same as described above.

[0101] In mixing the solvent mixture with the aerogel to produce the aerogel mixture, the detailed description of the aerogel may be similar or the same as described above.

[0102] In mixing the aerogel mixture with the fibrous support to produce the aerogel composition, the detailed description of the fibrous support may be similar or identical to the above description.

[0103] In each of mixing the solvent with a functional material including a binder, a dispersant or a combination thereof to produce a solvent mixture, mixing the solvent mixture with an aerogel to produce an aerogel composition, and mixing the aerogel mixture with a fibrous support to produce an aerogel composition, a mixer may be used for mixing. For example, the mixer may include, but is not limited to, a planetary mixer, a planetary Despa TM (PD) Mixer, Thinky TM mixer and C mixer.

[0104] As an example, a planetary mixer can be used to mix the solvent mixture with the aerogel. Using a planetary mixer to mix the solvent mixture with the aerogel can allow the aerogel to be substantially uniformly dispersed in the solvent.

[0105] A planetary mixer may be a device that can be used to mix or stir different substances in order to produce a homogenous mixture. A planetary mixer may include blades that are capable of planetary motion.

[0106] In example embodiments, the planetary mixer may include at least one of one or more planetary blades and one or more high-speed dispersing blades. As an example, the planetary mixer may include at least one planetary blade and at least one high-speed dispersing blade.

[0107] Each of the planetary blades and the high-speed dispersion blades may be configured to rotate continuously about its axis. The rotational speed may be expressed in revolutions per minute (rpm).

[0108] In an example 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. Low speed and high speed refer to the relative rotation speed between the first blade and the second blade. As an example, the first blade may be an open blade, and the second blade may be a Despa TM blade.

[0109] The rotation speed of the first blade may be, for example, in the range of about 10 rpm to 100 rpm, 10 rpm to 60 rpm, or 30 rpm to 70 rpm. The rotation speed of the second blade may be, for example, in the range of about 100 rpm to 2000 rpm, 100 rpm to 1000 rpm, 300 rpm to 1700 rpm, or 500 rpm to 1700 rpm.

[0110] When the functional material is added to the solvent and mixed with the solvent, the rotation speed of the first blade may be in the range of about 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 in the range of about 300 rpm to 1700 rpm, 600 rpm to 1000 rpm, or 700 rpm to 800 rpm. As described above, when the solvent and the functional material are mixed with each other, a solvent mixture in which a binder, a dispersant, or a combination thereof is substantially uniformly dispersed may be produced to facilitate mixing of the aerogel in a subsequent process.

[0111] When the solvent mixture and the aerogel powder are mixed with each other, the rotation speed of the first blade of the mixer may be in the range of about 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 in the range of about 500 rpm to 1700 rpm, 600 rpm to 1600 rpm, or 800 rpm to 1500 rpm. As described above, when the aerogel powder is added to the solvent mixture and mixed with the solvent mixture, the aerogel powder can be hindered or prevented from aggregating together to induce substantially uniform dispersion.

[0112] When the aerogel mixture and the fiber support are mixed with each other, the rotation speed of the first blade of the mixer may be in the range of about 10rpm to 60rpm, 20rpm to 50rpm, or 30rpm to 40rpm, and the rotation speed of the second blade may be in the range of about 300rpm to 1700rpm, 400rpm to 1500rpm, or 800rpm to 1200rpm. Mixing the aerogel mixture with the fiber support as described above can remove air bubbles in the composition, control viscosity, and facilitate the dispersion of the fiber support in the substantially uniformly dispersed aerogel, so that the aerogel surrounds the fiber support in the composition. A binder may be present between the aerogel and the fiber support to improve the bonding between the aerogel and the fiber support.

[0113] In example embodiments, 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 to have approximately 2 to 10 layers, 2 to 7 layers, or 2 to 5 layers.

[0114] The aerogel layer may be formed by, for example, extruding, coating or casting the aerogel composition using common methods.

[0115] By forming an aerogel layer using the method according to example embodiments, thermal insulation and durability of an insulating sheet for a battery may be improved, and when the insulating sheet for a battery is manufactured or installed in a device, aerogel may be hindered or prevented from falling off and generating dust.

[0116] In example embodiments, forming the coating layer to cover two or more surface portions among the entire surface of the aerogel layer may be performed by immersing the aerogel layer in a coating layer forming solution.

[0117] The coating forming solution may include a flexible polymer or a flexible polymer and a flame retardant. The detailed description of the flexible polymer and the flame retardant may be the same as above.

[0118] When the aerogel layer is immersed in a coating-forming solution, a coating-forming solution dispersed or dissolved using an appropriate solvent may be used, and in this case, the viscosity may be controlled to form a uniform coating.

[0119] In example embodiments, the aerogel layer may be immersed in a coating-forming solution, and may be dried at a temperature higher than a boiling point of the solvent to manufacture an insulating sheet for a battery according to example embodiments.

[0120] In example embodiments, the method may further include cross-linking the aerogel layer after immersing the aerogel layer in the coating-forming solution. Cross-linking may improve cohesion between the aerogel layer and the coating.

[0121] The cross-linking method is not particularly limited, and for example, a thermal cross-linking method and an ultraviolet (UV) cross-linking method may be used.

[0122] The thermal crosslinking may be performed at a temperature ranging from about 25° C. to 150° C. for 10 seconds to 30 minutes.

[0123] UV cross-linking can be performed by irradiating with UV light for about 10 seconds to 5 minutes.

[0124] For UV cross-linking, the coating-forming solution may further include a cross-linking agent.

[0125] The cross-linking agent is not particularly limited, and may be, for example, at least one of a multifunctional acrylate-based compound, an isocyanate-based compound, an epoxy-based compound, an aziridine-based compound, and a metal chelate-based compound.

[0126] The multifunctional acrylate compound may be, for example, at least one of pentaerythritol tri / tetraacrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, ethylene glycol diacrylate, and hexamethylene diacrylate.

[0127] The isocyanate compound may be, for example, at least one of toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isocyanate, tetramethylxylene diisocyanate, and naphthalene diisocyanate.

[0128] The epoxy compound may be, for example, at least one of ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, N,N,N′,N′-tetraglycidylethylenediamine and glycerol diglycidyl ether.

[0129] The aziridine compound may be, for example, at least one of N,N'-toluene-2,4-bis(1-aziridine carbonyl), N,N'-diphenylmethane-4,4'-bis(1-aziridine carbonyl), triethylenemelamine, bisisophthaloyl-1-(2-methylaziridine) and tris-1-aziridinylphosphine oxide.

[0130] The metal chelate type compounds may include, for example, compounds in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium or vanadium is coordinated with acetylacetone or ethyl acetoacetate.

[0131] For ultraviolet (UV) crosslinking, a photoinitiator may further be included.

[0132] The photoinitiator is not particularly limited, and may be, for example, at least one of benzophenone, acetophenone, chloroacetophenone, diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin acetic acid, benzoin acetate methyl ester, benzoin dimethyl ketal, 2,4-diethylthioxanthone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, diacetyl, β-chloroanthraquinone, thioxanthone, and 2-ethylanthraquinone.

[0133] In example embodiments, the substrate may be disposed on one surface or opposite surfaces of the insulating sheet for a battery. One surface may refer to an upper surface or a lower surface of the insulating sheet for a battery on which a coating is formed, and the opposite surfaces may refer to an upper surface and a lower surface of the insulating sheet for a battery on which a coating is formed.

[0134] For example, the substrate may include, but is not limited to, resin, metal, inorganic material other than metal, or a composite thereof. The substrate may be in the form of, but is not limited to, a film, a membrane, a sheet, and the like.

[0135] The resin may include, for example, at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide.

[0136] The metal may include, for example, at least one of copper, nickel, cobalt, iron, chromium, vanadium, palladium, ruthenium, rhodium, molybdenum, tungsten, iridium, silver, gold, and platinum. When a substrate made of or including the above metal is used, the substrate may be subjected to anti-corrosion treatment or insulation treatment as required.

[0137] The inorganic material other than the metal may include at least one of calcium carbonate (CaCO 3 ), talc, and mica.

[0138] As an example, the substrate may include an inorganic material, and as another example, the substrate may include mica. In this case, thermal insulation, durability, etc. of the insulating sheet may be improved.

[0139] A battery module according to example embodiments may include a plurality of battery cells and an insulating sheet for a battery disposed between the plurality of battery cells.

[0140] The battery cell may be a secondary battery cell. The secondary battery cell 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 having a positive electrode active material applied thereto and a negative electrode plate having a negative electrode active material applied thereto are arranged with a separator inserted therebetween, and the lithium secondary battery may be housed in a battery housing together with an electrolyte in a sealed state to constitute a secondary battery cell. Depending on the shape of the battery housing, the secondary battery cell may be classified into, for example, a cylindrical secondary battery cell, a prismatic secondary battery cell, or a pouch-shaped secondary battery cell, and a plurality of secondary battery cells may be connected in series or in parallel to each other to constitute a battery module.

[0141] The secondary battery cell may require a high degree of stability, for example, when overcharged, a positive electrode active material or an electrolyte may undergo decomposition and other side reactions, whereby heat may be emitted from the secondary battery cell, resulting in explosion of the secondary battery cell.

[0142] In an example embodiment, an insulating sheet including a coating formed to cover a portion or the entirety of a surface of the insulating sheet is disposed between battery cells, whereby the insulating sheet may have desired, advantageous, or improved thermal insulation, fire resistance, and flame retardancy or non-flammability, so that heat and flame in a battery cell due to thermal runaway of the battery cell may be suppressed from propagating to battery cells adjacent thereto.

[0143] Figure 1 is a schematic diagram illustrating a plurality of battery cells and an insulating sheet for a battery disposed between the battery cells according to an example embodiment.

[0144] refer to Figure 1 , the insulating sheet 100 for a battery according to an example embodiment may be disposed between a plurality of battery cells 200 included in a battery module. When the insulating sheet 100 for a battery according to an example embodiment is formed between a plurality of battery cells 200, a battery module and a battery pack including the same that can pre-impede or block flames in the event of thermal runaway of one battery cell, thereby substantially suppressing flame propagation to another battery cell with a higher safety level, can be provided.

[0145] Figure 2 is a schematic diagram illustrating a cross-sectional structure of an insulating sheet for a battery according to example embodiments.

[0146] refer to Figure 2, an insulating sheet 100 for a battery may be formed to have a structure including an aerogel layer 110 and a coating layer 120 formed on substantially the entire surface of the aerogel layer 110, wherein substantially the entire surface of the aerogel layer 110 includes an upper surface 111, a lower surface 112, and a boundary side surface 113 between the upper surface 111 and the lower surface 112.

[0147] Hereinafter, embodiments will be described. However, the following embodiments are intended only to illustrate or describe the present disclosure and should not be construed as limiting the present disclosure. Those skilled in the art can fully infer technically the details not described herein, so their description will be omitted.

[0148] (Manufacture of insulating sheets for batteries)

[0149] Example 1

[0150] 1. Manufacturing of aerogel layer

[0151] The precipitate was prepared by adding polyvinyl alcohol (Sigma Aldrich) as a binder to deionized water as a solvent and spinning at 30 rpm using an open blade and Despa TM The solvent mixture was prepared by mixing it with a blade at 700 rpm. Subsequently, the BET value was set to 800 m 2 / g of aerogel was added to the solvent mixture and the mixture was stirred at 70 rpm using an open blade and Despa TM The aerogel mixture was prepared by adding glass wool to the aerogel mixture and mixing with an open blade at 30 rpm and using a Despa TM A blade was used to mix it at 1200 rpm to produce an aerogel composition. A planetary mixer (DNTEK, PT-005) was used for mixing.

[0152] The solid content of the manufactured aerogel composition was found to be 50 wt% aerogel, 40 wt% glass wool and 10 wt% polyvinyl alcohol.

[0153] An aerogel layer is formed using the manufactured aerogel composition.

[0154] 2. Manufacturing of insulating sheets for batteries

[0155] The manufactured aerogel layer was immersed in a coating forming solution to form a coating on substantially the entire surface of the aerogel layer. The coating forming solution was manufactured to include 94.8 wt % of polyurethane (Shenzhen Ji'an Chemical Company, PU solution) and 4 wt % of ammonium phosphate (Merck) and 1.2 wt % of dipentaerythritol (Merck) as flame retardants.

[0156] After the aerogel layer was immersed in the coating forming solution, the aerogel layer was dried to manufacture an insulating sheet for a battery having a coating formed on substantially the entire surface of the aerogel layer. The total thickness of the manufactured insulating sheet for a battery was 3 mm, the thickness of the aerogel layer was 2.7 mm, and the thickness of the coating on the upper surface, the lower surface, and the boundary side surface of the aerogel layer was 0.15 mm.

[0157] Example 2

[0158] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that a coating forming solution including 94.8 wt % of silicone elastomer (Gelest, EXsil 100) and 4 wt % of ammonium phosphate (Merck) and 1.2 wt % of dipentaerythritol (Merck) as a flame retardant was used.

[0159] Example 3

[0160] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that the thickness of the aerogel layer and the coating layer were adjusted. It was found that the total thickness of the insulating 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.

[0161] Example 4

[0162] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that the thickness of the aerogel layer and the coating layer were adjusted. It was found that the total thickness of the insulating 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.

[0163] Example 5

[0164] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that a coating forming solution including 80 wt % polyurethane (Shenzhen Ji'an Chemical Co., Ltd., PU solution) and 15 wt % ammonium phosphate (Merck) and 5 wt % dipentaerythritol (Merck) as a flame retardant was used.

[0165] Example 6

[0166] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that a coating forming solution including 97.6 wt % polyurethane (Shenzhen Ji'an Chemical Co., Ltd., PU solution) and 1.8 wt % ammonium phosphate (Merck) and 0.6 wt % dipentaerythritol (Merck) as a flame retardant was used.

[0167] Example 7

[0168] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that a coating forming solution including 94.8 wt % polyurethane (Shenzhen Ji'an Chemical Co., Ltd., PU solution) and 4.0 wt % diammonium phosphate and 1.2 wt % dipentaerythritol (Merck) as a flame retardant was used.

[0169] Example 8

[0170] An insulating sheet for a battery was manufactured using substantially the same method as Example 1, except that a coating forming solution including 95 wt % of polyurethane (Shenzhen Ji'an Chemical Company, PU solution) and 5 wt % of ammonium hydroxide (Merck) as a flame retardant was used.

[0171] Comparative Example 1

[0172] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that an aerogel layer having no coating layer formed on its surface was used. The total thickness of the aerogel layer of the manufactured insulating sheet for a battery was found to be 3 mm.

[0173] Comparative Example 2

[0174] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that a coating-forming solution including 100 wt % of polyurethane (Shenzhen Ji'an Chemical Co., Ltd., PU solution) was used.

[0175] Comparative Example 3

[0176] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that a coating-forming solution comprising 84.8 wt % of polyurethane (Shenzhen Ji'an Chemical Co., Ltd., PU solution), 4 wt % of ammonium phosphate (Merck) and 1.2 wt % of dipentaerythritol (Merck) as a flame retardant, and 10 wt % of fumed silica as a filler was used.

[0177] Comparative Example 4

[0178] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that the coating layer was formed only on the upper surface of the aerogel layer, whereby the thickness of the aerogel layer was 2.7 mm and the thickness of the coating layer in the thickness direction was 0.3 mm.

[0179] Figure 3 2 is a schematic diagram showing the structure of an insulating sheet for a battery according to Comparative Example 4.

[0180] refer to Figure 3 , an insulating sheet 100 for a battery is formed to have a structure including an aerogel layer 110 and a coating layer 120 formed on an upper surface of the aerogel layer.

[0181] Comparative Example 5

[0182] An insulating sheet for a battery was manufactured using substantially the same method as in Example 1, except that the coating layer was formed only on the boundary side surface between the upper and lower surfaces of the aerogel layer, whereby the thickness of the aerogel layer in the thickness direction was 3 mm.

[0183] Figure 4 2 is a schematic diagram showing the structure of an insulating sheet for a battery according to Comparative Example 5.

[0184] refer to Figure 4 , an insulating sheet 100 for a battery is formed to have a structure including an aerogel layer 110 and a coating layer 120 formed on a boundary side surface between an upper surface and a lower surface of the aerogel layer.

[0185] (Experimental Example)

[0186] Experimental Example 1: Evaluation of coating properties

[0187] The elastic modulus of the coating layer of each of the insulating sheets for batteries manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 was evaluated.

[0188] The elastic modulus was measured according to ASTM D882, and the results are shown in Tables 1 and 2 below.

[0189] Experimental Example 2: Evaluation of Characteristics of Insulating Sheet for Battery

[0190] 1. Evaluation of thermal insulation

[0191] The thermal insulation of each of the insulating sheets manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 was evaluated.

[0192] Each insulating sheet was placed between a pair of opposing 1T thick aluminum plates and placed on a hot press. The upper plate of the hot press was heated to 350°C, and the lower plate of the hot press was not heated and maintained at a starting temperature of 40°C. Subsequently, a pressure of 20 kN was applied to the lower plate of the hot press, and the maximum temperature of the lower plate of the hot press was measured within 11 minutes. The results are shown in Tables 1 and 2 below.

[0193] 2. Evaluation of compressibility

[0194] Each of the insulating sheets manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 was cut into a size of 140 mm×100 mm, and the compressibility thereof was evaluated.

[0195] The ratio of the thickness measured by a universal testing machine (UTM) apparatus at an applied load of 5 kN to the thickness measured by the UTM apparatus at an applied load of 40 kN was measured. The results are shown in Tables 1 and 2 below.

[0196] 3. Evaluation of flame retardancy

[0197] The flame retardancy of each of the insulating sheets manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 was evaluated.

[0198] The flame retardancy was evaluated according to the UL-94V flame retardancy determination test (UL-94V test (vertical burning test) method, with ratings of V-0, V-1, and V-2, and the results are shown in Tables 1 and 2 below.

[0199] 4. Evaluation of dust formation

[0200] The dust-generating property of each insulating sheet manufactured in Examples 1 to 8 and Comparative Examples 1 to 5 was evaluated.

[0201] The dust formation property was evaluated by measuring the weight loss through vibration evaluation. A sample of 140 mm×100 mm was vibrated at 30 Hz for 1 hour using a vibration evaluation device, and the weight loss was measured by the following Equation 1.

[0202] [Equation 1]

[0203] Weight loss = (sample weight before vibration evaluation - sample weight after vibration evaluation) / sample weight before vibration evaluation * 100

[0204] The results are shown in the following Tables 1 and 2. When the weight loss was less than 1 wt %, the dust formation property of the insulating sheet was evaluated as good, and when the weight loss was 1 wt % or more, the dust formation property of the insulating sheet was evaluated as poor.

[0205] [Table 1]

[0206]

[0207] [Table 2]

[0208]

[0209] In the above Table 2, NG means an evaluation result that does not satisfy the V-2 rating.

[0210] Referring to Tables 1 and 2 above, it can be seen that Comparative Example 1 (wherein the thickness of the aerogel layer is 3 mm) has higher thermal insulation than Examples 1 to 8, but due to the absence of a coating, compressibility and dust formation are reduced. In Comparative Example 2 (wherein a flame retardant is not included in the coating), flame retardancy cannot be ensured. In Comparative Example 3 (wherein 10 wt % of a filler is included in the coating), the elastic modulus of the coating is greatly increased, and the compressibility of the insulating sheet is greatly reduced. In Comparative Example 4 (wherein a coating is formed only on the upper and lower surfaces of the aerogel layer), dust formation is reduced. In Comparative Example 5 (wherein a coating is formed only on the boundary side surface of the aerogel layer), compressibility is reduced.

[0211] Therefore, it can be seen that the insulation sheet for a battery according to example embodiments has desirable, improved or advantageous thermal insulation, compressibility, flame retardancy and dust formation properties.

[0212] As is apparent from the above description, the insulating sheet for a battery according to the example embodiments may have desired, improved or advantageous thermal insulation, fire resistance and flame retardancy or non-flammability, thereby possibly reducing or inhibiting the propagation of heat and flame in a battery cell to battery cells adjacent thereto due to thermal runaway of the battery cell.

[0213] The insulating sheet for a battery according to example embodiments may have desired, improved or advantageous compressibility, mechanical strength and dimensional stability, and may reduce or prevent the aerogel layer from falling off due to external impact, thereby being able to improve workability and reduce or prevent contamination of instruments.

[0214] Although the foregoing describes example embodiments, the present disclosure is not limited thereto, and it is contemplated that various modifications may be made within the scope of the claims, detailed description of example embodiments, and the accompanying drawings, and that these modifications also fall within the scope of the present disclosure.

Claims

1. An insulating sheet for a battery, the insulating sheet comprising: an aerogel layer comprising an aerogel; and a coating configured to cover the entire surface of the aerogel layer, wherein The coating comprises a flexible polymer and a flame retardant dispersed in the flexible polymer, and The coating has an elastic modulus of 8 MPa or less as measured according to ASTM D882.

2. The insulating sheet according to claim 1, wherein the aerogel has a 2 / g~1,000m 2 / g in the range of BET specific surface area.

3. The insulation sheet according to claim 1, wherein the aerogel layer further comprises a fiber support and a functional material, the functional material comprising at least one of a binder and a dispersant.

4. The insulating sheet of claim 3, wherein the fiber support comprises at least one of natural fiber, silica fiber, glass fiber, carbon fiber, graphite fiber, mineral fiber, and polymer fiber.

5. The insulation sheet of claim 3, wherein the binder comprises a water-based polymer binder. 6 . The insulating sheet according to claim 3 , wherein the dispersant comprises at least one of a surfactant, a silane coupling agent, and a phosphate ester salt.

7. The insulating sheet according to claim 3, wherein the aerogel is included in a range of 10 wt% to 90 wt%, the fibrous support is included in a range of 5 wt% to 70 wt%, and the functional material is included in a range of 0.5 wt% to 20 wt%, based on the total amount of the aerogel layer. 8 . The insulating sheet of claim 1 , wherein the flexible polymer comprises at least one of a fluorinated polymer, a polyurethane-based polymer, a polyolefin-based polymer, and a silicone-based polymer. 9 . The insulating sheet of claim 1 , wherein the flame retardant comprises at least one of an inorganic flame retardant, a phosphorus-based flame retardant, a nitrogen compound-based flame retardant, a silicone-based flame retardant, a melamine-based flame retardant, a halogen-based flame retardant, and a polyol-based flame retardant.

10. The insulating sheet of claim 1, wherein the flame retardant comprises at least one of a phosphorus-based flame retardant and a polyol-based flame retardant. 11 . The insulating sheet according to claim 10 , wherein the flame retardant comprises a phosphorus-based flame retardant and a polyol-based flame retardant in a weight ratio ranging from 1:0.1 to 1:0.

5.

12. The insulating sheet according to claim 1, wherein the content of the flame retardant is in the range of 1 wt% to 25 wt% based on the total amount of the coating layer.

13. The insulation sheet of claim 1, wherein the coating layer does not include a filler. 14 . The insulating sheet according to claim 1 , wherein a thickness of the coating layer is 20% or less of a total thickness of the insulating sheet for a battery.

15. The insulating sheet according to claim 1, wherein The flexible polymer includes at least one of a polyurethane polymer and a silicone polymer, and The flame retardant includes at least one of a polyol flame retardant and a phosphorus flame retardant.

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

17. A battery module, comprising: Multiple battery cells; and An insulating sheet according to any one of claims 1 to 15 or an insulating sheet manufactured according to the method according to claim 16 between the plurality of battery cells.

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