Battery module, manufacturing method thereof, and battery pack including the same

Abstract

To provide a battery module 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 pack including the same.SOLUTION: The present invention relates to a battery module. The battery module includes a plurality of cells and an insulation member provided between the plurality of cells, the insulation member having an upper surface and a lower surface disposed so as to face cells adjacent thereto, respectively. The insulation member includes a first insulation sheet, a second insulation sheet, and an expansion layer formed between the first insulation sheet and the second insulation sheet. The present invention further relates to a method of manufacturing the battery module, and a battery pack including the battery module.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery module, a manufacturing method thereof, and a battery pack including the same. [Background technology]

[0002] Secondary batteries are power storage systems that provide excellent energy density by converting electrical energy into chemical energy and storing it. Unlike primary batteries, which cannot be recharged, secondary batteries can be recharged, and are widely used in IT devices such as smartphones, cellular phones, laptops, and tablet PCs. In recent years, interest in electric vehicles has increased 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 cells such as lithium secondary batteries, one cell may overheat for some reason and experience thermal runaway, adversely affecting other adjacent cells, so it is required that adjacent cells are thermally insulated from each other.

[0004] Therefore, conventionally, a plate material or an insulating resin plate is placed between the cells to insulate and heat the adjacent cells.

[0005] The above information disclosed in the Background of the Invention is intended to enhance the understanding of the background of the present invention only, and may therefore 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 module having excellent heat insulation properties as well as fire resistance and flame retardancy or non-combustibility in order to suppress heat propagation between adjacent cells due to thermal runaway of a battery, a manufacturing method thereof, and a battery pack including the same. [Means for solving the problem]

[0007] One embodiment provides a battery module including a plurality of cells and insulating members provided between the plurality of cells, each arranged such that an upper surface and a lower surface face an adjacent cell, the insulating member including a first insulating sheet, a second insulating sheet, and an expansion layer formed between the first insulating sheet and the second insulating sheet.

[0008] The cell may be a secondary battery cell.

[0009] The first and second insulation sheets may each include a substrate and an aerogel layer formed on the substrate.

[0010] The substrates of the first and second insulation sheets may be positioned so as to face the adjacent cells, and the aerogel layers may be positioned so as to face the expanded layers.

[0011] The base material of each of the first and second heat insulating sheets may be formed of one or more materials selected from the group consisting of resins, metals, and inorganic materials other than metals.

[0012] The aerogel layers of the first and second insulation sheets may each comprise an aerogel, a fibrous support, and a functional material including a binder, a dispersant, or a combination thereof.

[0013] The aerogel has a BET specific surface area of ​​500 m 2 / g~1,000m 2 / g.

[0014] 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.

[0015] The binder may include a water-based polymeric binder.

[0016] The dispersant may be one or more selected from the group consisting of a surfactant, a silane coupling agent, and a phosphate salt.

[0017] 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.

[0018] The expandable layer may be one or more selected from the group consisting of foaming materials that expand when the ambient temperature increases to 100°C to 200°C, and flame-retardant materials with a melting temperature of 60°C to 100°C.

[0019] The foaming substance is at least one selected from the group consisting of expanded graphite, an organic foaming agent, and an inorganic foaming agent. The organic foaming agent is at least one selected from the group consisting of azodicarbonamide, dinitropentamethylenetetramine, and oxybis(benzenesulfonylhydrazide). The inorganic foaming agent may be at least one selected from the group consisting of hydrogen carbonate, carbonate, and organic acid salt.

[0020] The flame retardant material may be at least one selected from the group consisting of polyurethane, polyvinyl chloride, and polymers having a flame retardant dispersed therein.

[0021] The thickness of the expansion layer may be 1% to 30% of the total thickness of the heat insulating member.

[0022] When the expansion layer expands, the expansion layer flows out from a side surface of the heat insulating member to form an outflow portion, and the length of the outflow portion from the side surface of the heat insulating member may be 500% to 3000% of the thickness of the expansion layer.

[0023] The battery module may include an empty space other than the space in which the cells and the insulating member are arranged, and may further include a coating layer formed to cover a side of the insulating member in the empty space formed at the bottom of the battery module, and the coating layer may include a flexible polymer.

[0024] The flexible polymer may be at least one selected from the group consisting of a fluorine-based polymer, a polyurethane-based polymer, a polyolefin-based polymer, and a silicon-based polymer.

[0025] Another embodiment provides a method for manufacturing a battery module, the method including: manufacturing an insulating member; and disposing the insulating member between a plurality of cells such that an upper surface and a lower surface of the insulating member face an adjacent cell, respectively, the insulating member including a first insulating sheet, a second insulating sheet, and an expansion layer formed between the first insulating sheet and the second insulating sheet.

[0026] Yet another embodiment provides a battery pack including the battery module. Effect of the Invention

[0027] A battery module according to an embodiment can suppress the propagation of heat and flames to adjacent cells due to thermal runaway of a cell.

[0028] In addition, the insulating sheet provided in the battery module according to an embodiment has excellent compression performance, mechanical strength, and dimensional stability in addition to thermal insulation properties, and therefore can prevent the aerogel layer from falling off due to external impact, making it easy to work with and preventing contamination of the mechanism. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram showing a structure of a battery module according to an embodiment. [Diagram 2] 4 is a schematic diagram illustrating a state after an expansion layer has expanded in a battery module according to an embodiment; FIG. [Diagram 3] 1 is a schematic diagram showing a cross-sectional structure of a heat insulating member according to one embodiment. [Figure 4] FIG. 13 is a schematic diagram showing a structure of a battery module according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Although the present invention will be described in detail below so as to be easily understood by those skilled in the art, the present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0031] A battery module according to one embodiment includes a plurality of cells and insulating members each provided between the plurality of cells and arranged such that an upper surface and a lower surface face an adjacent cell, and the insulating members may include a first insulating sheet, a second insulating sheet, and an expansion layer formed between the first insulating sheet and the second insulating sheet.

[0032] The battery module having the above structure has excellent heat insulation properties, as well as fire resistance and flame retardancy or non-combustibility, and can suppress the propagation of heat and flame to adjacent cells due to thermal runaway of a cell. In addition, the heat insulation sheet has excellent compression performance, can ensure mechanical strength and dimensional stability, can prevent the aerogel layer from falling off due to external impact, and can facilitate work and prevent contamination of the mechanism.

[0033] In one embodiment, 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, on which a positive electrode active material and a negative electrode active material are respectively applied, are arranged with a separator sandwiched therebetween, and are sealed in a battery case together with an electrolyte to form a secondary battery cell. Depending on the shape of the battery case to be formed, it may be classified into a cylindrical type, a rectangular type, or a pouch type, and a plurality of secondary battery cells are connected in series or parallel to form a battery module.

[0034] Such secondary batteries require high stability. For example, if the secondary batteries are overcharged, decomposition reactions of the positive electrode active material or electrolyte and other side reactions may occur, and these reactions may release heat, which may eventually lead to an explosion of the secondary battery cell.

[0035] In this regard, in the present invention, an insulating member including a first insulating sheet, a second insulating sheet, and an expansion layer formed between the first insulating sheet and the second insulating sheet is disposed between each of the cells, and in addition to excellent insulating properties, the insulating member has fire resistance and flame retardancy or non-combustibility, and can suppress the propagation of heat and flame to adjacent cells due to thermal runaway of a cell.

[0036] FIG. 1 is a schematic diagram showing a battery module having a plurality of cells each having a heat insulating member disposed between the cells.

[0037] 1, a battery module 1000 according to an embodiment may include a plurality of cells 100 and may include a heat insulating member 200 provided between each of the plurality of cells 100. Here, the heat insulating member 200 may include a first heat insulating sheet 210, a second heat insulating sheet 220, and an expansion layer 230 formed between the first heat insulating sheet 210 and the second heat insulating sheet 220. As a result, when a thermal runaway occurs in one cell, a flame is first blocked to minimize the spread of the flame to other cells, thereby providing a battery module with improved safety, and further providing a secondary battery pack including the secondary battery module.

[0038] The insulating member includes an upper surface, a lower surface, and an edge side surface between the upper surface and the lower surface, and when the upper surface and the lower surface of the insulating member respectively face adjacent cells, the edge side surface of the insulating member may positionally include an upper surface, a lower surface, a front surface, and a rear surface.

[0039] FIG. 2 is a schematic diagram showing a case where the expansion layer expands at a certain temperature or higher and flows out onto the upper and lower side surfaces of the heat insulating member.

[0040] Referring to FIG. 2, a battery module 1000 according to one embodiment includes a plurality of cells 100 and an insulating member 200 provided between the plurality of cells 100. The insulating member 200 may include a first insulating sheet 210, a second insulating sheet 220, and an expansion layer 230 formed between the first insulating sheet 210 and the second insulating sheet 220. When the ambient temperature increases above a certain temperature due to thermal runaway, the expansion layer 230 expands, and the plurality of cells 100 formed on both sides of the insulating member 200 also expand, causing the expansion layer 230 to flow out from the upper and lower sides of the insulating member 200 to form an outflow portion 231, thereby filling the empty space in the battery module 1000 and preventing flame propagation.

[0041] In one embodiment, the first and second insulation sheets may each include a substrate and an aerogel layer formed on the substrate, wherein the substrates of the first and second insulation sheets may face the adjacent cells, and the aerogel layers may face the expansion layer.

[0042] FIG. 3 is a schematic diagram showing the structure of a heat insulating member according to one embodiment.

[0043] Referring to FIG. 3, the first insulation sheet 210 may include a first substrate 211 and a first aerogel layer 212 formed on the first substrate 211. The second insulation sheet 220 may include a second substrate 221 and a second aerogel layer 222 formed on the second substrate 221. Here, the first substrate 211 and the second substrate 221 may face adjacent cells, and the first aerogel layer 212 and the second aerogel layer 222 may face an expansion layer 230, forming an insulation member 200. When an insulation member having such a structure is included, the expansion layer spreads into an empty space in the battery module during thermal runaway to fill the empty space, thereby preventing a flame from spreading into the empty space.

[0044] Hereinafter, even if there is no description of first or second, the insulating sheet can mean the first insulating sheet, the second insulating sheet, or both the first insulating sheet and the second insulating sheet, the substrate can mean the first substrate, the second substrate, or both the first substrate and the second substrate, and the aerogel layer can mean the first aerogel layer, the second aerogel layer, or both the first aerogel layer and the second aerogel layer.

[0045] The substrates of the first and second heat insulating sheets, i.e., the first substrate and the second substrate, may be formed of at least one material selected from the group consisting of resins, metals, and inorganic materials other than metals, or may be composites thereof, and the type of substrate is not limited. The form of the substrate may be a film, a thin film, a sheet, or the like, and is not particularly limited.

[0046] The resin may be, for example, one or more selected from the group consisting of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide.

[0047] The metal may be, 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 the above metal material, the substrate may be subjected to anti-corrosion treatment, insulation treatment, etc., as necessary.

[0048] The inorganic material may be one or more selected from the group consisting of calcium carbonate (CaCO3), talc, and mica.

[0049] As a specific example, the substrate may include an inorganic material, and more specifically, may include mica, which can improve the heat insulating property and durability of the heat insulating sheet.

[0050] The aerogel layers of the first and second insulation sheets, i.e., the first and second aerogel layers, may each comprise an aerogel, a fibrous support, and a functional material including a binder, a dispersant, or a combination thereof.

[0051] 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~950m 2 / 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.

[0052] 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 an aerogel having a particle size within the above range, the heat insulating properties can be improved and the heat transfer between the multiple cells can be delayed.

[0053] The content of the aerogel may be 10% by weight to 90% by weight, 30% by weight to 70% by weight, or 40% by weight to 60% by weight based on the total amount of the aerogel layer. By including the aerogel within the above range, excellent heat insulating properties of the heat insulating sheet can be obtained.

[0054] On the other hand, aerogel is a transparent or translucent advanced material with a nanoporous structure, and has very low density and low thermal conductivity. As a result, it not only has great potential as an insulating material, but is also evaluated as a highly efficient super-insulating material that can be used in a variety of industrial fields.

[0055] The greatest advantage of aerogel is that it exhibits a lower thermal conductivity than conventional organic insulation materials such as styrofoam, and that it can solve the problem of fire vulnerability and generation of harmful gases during fire, which are fatal weaknesses of organic insulation materials. However, aerogel has a very low strength, such as being easily broken even by small impacts due to its high brittleness, and is difficult to process into a very thin thickness and shape, so that it is very difficult to manufacture an insulation material using aerogel alone, despite its excellent insulation properties. Therefore, in one embodiment, the durability of the aerogel layer can be improved by including a fibrous support and a functional material including a binder, a dispersant, or a combination thereof, and the generation of dust during external impacts and work can be prevented.

[0056] By including the fibrous support in the aerogel layer, the durability of the heat insulating sheet formed using the same can be improved.

[0057] The fibrous support may include fibers used as supports for ordinary heat insulating materials. For example, the fibrous support may be one or more 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 glass fibers, but is not limited thereto.

[0058] The natural fibers may be, for example, one or more selected from the group consisting of hemp, jute, flax, coir, hemp, and cellulose.

[0059] The mineral fibers may be, for example, one or more mineral fibers selected from the group consisting of basalt, wollastonite, alumina, silica, slag, and rock.

[0060] 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). As a specific example, the polymer fiber may be, but is not limited to, one or more selected from the group consisting of polyimide, polyamide, and polybenzimidazole.

[0061] The fibrous support may be, for example, in the form of wool or chopped strands, but is not limited thereto.

[0062] The diameter 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 a diameter within the above range, the structure of the aerogel layer can be made stronger, and the production cost can be reduced.

[0063] The content of the fibrous support may be 5% by weight to 70% by weight, 25% by weight to 60% by weight, or 30% by weight to 50% by weight, based on the total amount of the aerogel layer. When an aerogel layer containing a fibrous support within the above range is formed to produce a heat insulating sheet, durability can be improved.

[0064] The binder may include a water-based polymer binder. For example, the water-based polymer binder may be at least one selected from the group consisting of a water-based polymer, an anionic water-soluble polymer, a cationic water-soluble polymer, and a water-dispersible polymer.

[0065] The aqueous polymer may be, for example, at least one selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinylpyrrolidone, but is not limited thereto.

[0066] The anionic water-soluble polymer may be at least one selected from the group consisting of polymers having functional groups of 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.

[0067] The cationic water-soluble polymer may be at least one selected from the group consisting of polymers having functional groups of amine, ammonium, phosphonium, sulfonium, and salts thereof. For example, the cationic water-soluble polymer may be a polymer having an amine group, and a specific example may be at least one selected from the group consisting of polyethylene amine and polyamine, but is not limited thereto.

[0068] 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.

[0069] The binder may include a water-based polymer and a water-dispersible polymer, for example, a water-based polymer having binder properties as well as dispersion properties, and a water-dispersible polyurethane having fire-resistant properties, and a specific example thereof may include polyvinyl alcohol and water-dispersible polyurethane.

[0070] The weight ratio of the aqueous polymer and 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 and the water-dispersible polymer is used in combination within the above range, the heat insulation property, dust resistance, and compressibility of the heat insulation sheet can be further improved as well as the fire resistance and mechanical properties.

[0071] The content of the binder may be 0.5% by weight to 20% by weight, 2% by weight to 15% by weight, or 8% by weight to 15% by weight, based on the total amount of the aerogel layer. A heat insulating sheet including an aerogel layer containing a binder within the above range may have improved dust characteristics.

[0072] 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.

[0073] When the dispersant is further included, the dispersion of the aerogel is improved during the preparation of the aerogel layer, and the aerogel can be uniformly dispersed in the fibrous support.

[0074] The content of the dispersant may be 0.1% by weight to 6% by weight, 0.1% by weight to 5% by weight, or 0.1% by weight to 3% by weight, based on the total amount of the aerogel layer. By including the dispersant within the above range, an aerogel layer can be produced at low cost, and an insulating sheet having excellent insulating properties, uniformity, and dust characteristics can be produced using the aerogel layer.

[0075] 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.

[0076] In one embodiment, the fibrous support may comprise 25% by weight to 60% by weight, the aerogel may comprise 30% by weight to 70% by weight, and the binder may comprise 2% by weight to 15% by weight, based on the total amount of the aerogel layer.

[0077] 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 amount of the aerogel layer. When the aerogel layer is formed within the above ranges, excellent heat insulation can be achieved and durability can be improved, the bonding strength between the fibrous support and the aerogel can be improved, and dust generation can be prevented.

[0078] In one embodiment, the aerogel layer may contain, relative to the total amount of the aerogel layer, 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.

[0079] 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 the above ranges, excellent heat insulation can be achieved and durability can be improved, the bonding strength between the fibrous support and the aerogel can be improved, and dust generation can be prevented.

[0080] In one embodiment, the expandable layer may be made of at least one selected from the group consisting of a foaming material that foams when the ambient temperature increases to 100°C to 200°C, and a flame-retardant material having a melting temperature of 60°C to 100°C.

[0081] The foaming material is not particularly limited as long as it foams and expands in volume when the ambient temperature increases to, for example, 100° C. to 200° C., 120° C. to 180° C., or 120° C. to 170° C., and may include, for example, one or more foaming agents selected from the group consisting of expanded graphite, organic foaming agents, and inorganic foaming agents. As a specific example, the organic foaming agent may be one or more selected from the group consisting of azodicarbonamide, dinitropentamethylenetetramine, and oxybis(benzenesulfonylhydrazide), and the inorganic foaming agent may be one or more selected from the group consisting of hydrogen carbonate, carbonate, and organic acid salt.

[0082] The foaming material may be mixed with a polymeric material to form a coating liquid. The polymeric material is not particularly limited as long as it can control the thickness of the expanded layer after expansion and the foaming trigger temperature of the foaming material, and may be, for example, at least one selected from the group consisting of polyimide, polyamide, polybenzimidazole, polybenzoxazole, polyamideimide, polyurethane, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyethylene (PE), and polypropylene (PP).

[0083] Here, the coating liquid containing the foaming material and the polymeric material may foam and expand in volume when the ambient temperature increases to, for example, 100°C to 200°C, 120°C to 180°C, or 120°C to 170°C.

[0084] The foaming material and the polymeric material may form a coating liquid in a weight ratio of 1:9 to 5:5, 1:9 to 4:6, or 1:9 to 3:7.

[0085] The flame retardant material is not particularly limited as long as it has a melting temperature of, for example, 60° C. to 100° C. or 80° C. to 100° C., and may be, for example, one or more selected from the group consisting of polyurethane, polyvinyl chloride, and polymers having a flame retardant dispersed therein. Here, the flame retardant may include the types of flame retardants described below.

[0086] When the expansion layer is formed using the foaming material and the flame retardant material, the expansion layer quickly leaks from the edge side of the insulating member to the upper and lower parts under a certain temperature condition to fill the empty space in the battery module, thereby preventing the spread of flame. Here, the upper and lower parts may refer to the upper and lower parts based on the shape in which the insulating member is arranged.

[0087] The expansion layer may be formed to have a thickness of 1% to 30%, 5% to 25%, or 10% to 17% of the total thickness of the heat insulating member. By forming the expansion layer with a thickness within the above range, it is possible to effectively prevent flame propagation during thermal runaway of one cell.

[0088] The expandable layer expands under a certain temperature condition and flows out from the side of the heat insulating member, and the length of the outflow portion formed by the expansion layer flowing out from the side of the heat insulating member may be 500% to 3000%, 1000% to 2500%, or 1300% to 2000% of the thickness of the expansion layer before expansion. Specifically, the expandable layer expands when the surrounding temperature rises to a certain level or more, and the length of the outflow portion after expansion may increase 5 to 30 times, 10 to 25 times, or 13 to 20 times compared to the thickness before expansion.

[0089] The battery module may include an empty space other than the space in which the cells and the heat insulating member are formed, and the length of the outflow portion may be 200% or more, 200% to 500%, or 200% to 400% of the height of the empty space formed in the upper part of the battery module. Specifically, the length of the outflow portion may be 2 times or more, 2 times to 5 times, or 2 times to 4 times the height of the empty space formed in the upper part of the battery module.

[0090] In one embodiment, the battery module includes an empty space other than the space in which the cells and the insulating member are disposed, and further includes a coating layer formed to cover a side of the insulating member in the empty space formed in the lower part of the battery module, and the coating layer may include a flexible polymer. By forming the coating layer, an expansion layer between the first insulating sheet and the second insulating sheet is concentrated and flows out to the upper part during thermal exposure, and in this case, a flame moving to the upper part can be effectively blocked.

[0091] FIG. 4 is a schematic diagram showing a battery module including a coating layer formed to cover a side surface of the heat insulating member in an empty space formed under the battery module.

[0092] Referring to FIG. 4, a battery module 1000 according to an embodiment may include a plurality of cells 100 and a heat insulating member 200 provided between the plurality of cells 100. Here, the heat insulating member 200 may include a first heat insulating sheet 210, a second heat insulating sheet 220, and an expansion layer 230 formed between the first heat insulating sheet 210 and the second heat insulating sheet 220. Also, a coating layer 300 may be formed to cover a side surface of the heat insulating member 200 in an empty space formed in the lower part of the battery module 1000. As a result, when a thermal runaway occurs in one cell, the expansion layer 230 effectively flows out in an upward direction, blocking a flame moving upward and effectively suppressing the propagation of the flame to other cells.

[0093] The flexible polymer is not particularly limited as long as it is a polymer having flexibility, and may be, for example, one or more types selected from the group consisting of fluorine-based polymers, polyurethane-based polymers, polyolefin-based polymers, and silicon-based polymers.

[0094] 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 has flexibility and flame retardancy by itself.

[0095] The polyurethane polymer is not particularly limited as long as it is a normal polyurethane produced by polymerization of a polyol and a polyisocyanate. Here, the polyol may be, for example, a normal 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. 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.

[0096] 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.

[0097] The silicon-based polymer may be, for example, one or more selected from the group consisting of polydimethylsiloxane, polymethylethylsiloxane, polydiethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and polyethylphenylsiloxane.

[0098] The coating layer may further include a flame retardant. 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, and halogen-based flame retardants.

[0099] The inorganic flame retardant may include a metal oxide, a metal hydroxide, or a combination thereof. For example, the inorganic flame retardant may be one or more selected from the group consisting of silicon oxide, magnesium hydroxide, aluminum hydroxide, antimony oxide, sodium carbonate, zinc oxide, iron oxide, tin oxide, zinc borate, and calcium borate, but is not limited thereto.

[0100] The phosphorus-based flame retardant includes a typical phosphorus-containing flame retardant, and may be, 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.

[0101] 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 polyphosphate having a multifunctional hydroxyl group. When a phosphorus-based flame retardant having a multifunctional hydroxyl group is used, excellent flame retardancy can be obtained.

[0102] 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 aliphatic amide, an aromatic amide, urea, and thiourea, but is not limited thereto.

[0103] The silicone-based flame retardant may include a silicone resin, a silicone oil, or a combination thereof. The silicone resin may include a resin having a structure of RSiO. Here, 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 of the hydrogens of the alkyl group and the aromatic group are substituted with a vinyl group. The silicone oil may be 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 end of polydimethylsiloxane is modified with one or more of hydrogen, an alkyl 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, but is not limited thereto.

[0104] 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.

[0105] The halogen-based flame retardant can be any halogen-based compound that can act as a flame retardant, without limitation. For example, the halogen-based flame retardant can be one or more selected from the group consisting of decabromodiphenyl ether, decabromodiphenylethane, tetrabromobisphenol-A, tetrabromobisphenol-A epoxy oligomer, octa-bromotrimethylphenylindane, ethylene-bis-tetrabromophthalimide, tris(tribromophenol)triazine, and brominated polystyrene, but is not limited thereto.

[0106] The content of the flame retardant may be 1 to 10% by weight, 2 to 8% by weight, or 3 to 6% by weight based on the total amount of the coating layer. By forming a coating layer containing a flame retardant within the above range, dust generation of the aerogel can be prevented and the flame retardancy or non-combustibility of the heat insulating member can be improved.

[0107] A manufacturing method for a battery module according to one embodiment includes the steps of manufacturing an insulating member and disposing the insulating member between a plurality of cells such that an upper surface and a lower surface of the insulating member face adjacent cells, respectively, and the insulating member may include a first insulating sheet, a second insulating sheet, and an expansion layer formed between the first insulating sheet and the second insulating sheet.

[0108] In one embodiment, the step of manufacturing the insulation member may include the steps of manufacturing a first insulation sheet, manufacturing a second insulation sheet, and laminating an expansion layer between the first insulation sheet and the second insulation sheet.

[0109] The step of producing the first insulation sheet may include forming a first substrate and applying an aerogel composition onto the first substrate to form a first aerogel layer.

[0110] The step of producing the second insulation sheet may include forming a second substrate and applying an aerogel composition onto the second substrate to form a second aerogel layer.

[0111] The specific description of each of the first and second substrates may be as described above, and the size and shape may be appropriately adjusted according to the cell structure.

[0112] The aerogel composition may include a step of preparing a solvent mixture by mixing a functional material including a binder, a dispersant, or a combination thereof with a solvent, a step of preparing an aerogel mixture by mixing the solvent mixture and an aerogel, and a step of preparing an aerogel composition by mixing the aerogel mixture and a fibrous support, thereby forming a first aerogel layer, a second aerogel layer, or a first aerogel layer and a second aerogel layer.

[0113] 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.

[0114] The solvent may be one or more selected from the group consisting of polar solvents and non-polar solvents.

[0115] The polar solvent may be one or more selected from the group consisting of water and alcohol-based solvents.

[0116] The water may be, for example, one or more types selected from the group consisting of purified water and ultrapure water.

[0117] 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.

[0118] The non-polar solvent may include a hydrocarbon solvent, for example, one or more 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.

[0119] The solvent may include water. When water is used as the solvent, raw material costs and post-treatment costs can be effectively reduced. However, when water is used as the solvent, there is a problem that it is not easy to mix with the hydrophobic aerogel. In one embodiment, the aerogel is uniformly dispersed by controlling the mixing stage design, mixing conditions, addition and amount of binder and dispersant, etc. When the aerogel is uniformly dispersed in the composition in this way, an aerogel layer having excellent heat insulation, durability, and low dust properties can be formed with a thin thickness without using a large amount of binder.

[0120] The solvent may be contained in such a way that the weight ratio of the solvent to the total amount of solids in the aerogel composition is 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 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 within the above range, it is possible to achieve both dispersibility, coatability, and phase stability.

[0121] The specific explanation regarding the binder and dispersant may be as described above.

[0122] 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.

[0123] 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 as described above.

[0124] In each of the steps of preparing a solvent mixture by mixing a functional material including a binder, a dispersant, or a combination thereof with the solvent, preparing an aerogel mixture by mixing the solvent mixture and an aerogel, and preparing an aerogel composition by mixing the aerogel mixture and 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 planetary desper mixer (PD mixer), a thinky mixer, a C-mixer, etc.

[0125] As a specific example, a planetary mixer may be used to mix the solvent mixture and the aerogel. When the solvent mixture and the aerogel are mixed using the planetary mixer, the aerogel can be uniformly dispersed in the solvent.

[0126] The planetary mixer may be a device that can be used to mix or stir different materials to produce a homogenous mixture, and may include blades that are capable of planetary motion.

[0127] 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.

[0128] 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).

[0129] 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.

[0130] The rotation speed of the first blade may be, for example, 10 rpm to 100 rpm, 10 rpm to 60, 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.

[0131] When the functional material is mixed in the solvent, the rotation speed of the first blade 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, 600 rpm to 1000 rpm, or 700 rpm to 800 rpm. By mixing the solvent and the functional material as described above, a solvent mixture in which the binder, dispersant, or a combination thereof is uniformly dispersed is prepared, and aerogel mixing in the subsequent step can be performed more easily.

[0132] When the solvent mixture and the aerogel powder are mixed, 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.

[0133] When the aerogel mixture and the fibrous support are mixed, 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. When the aerogel mixture and the fibrous support are mixed in this way, the air bubbles in the composition are removed, the viscosity is adjusted, and the fibrous support is easily dispersed between the uniformly dispersed aerogel, so that the aerogel may be present in the composition in a form in which the periphery of the fibrous support is covered by the aerogel. Here, a binder is present between the aerogel and the fibrous support, which can improve the binding force between the aerogel and the fibrous support.

[0134] By forming an aerogel layer using a method according to an embodiment, durability as well as thermal insulation properties are improved, and it is possible to prevent the aerogel from falling off and generating dust when manufacturing an insulating member, installing it inside an apparatus, or when external vibration occurs.

[0135] In one embodiment, the step of forming an expansion layer between the first insulation sheet and the second insulation sheet and laminating them may include disposing the first aerogel layer of the first insulation sheet and the second aerogel layer of the second insulation sheet to face each other, and forming an expansion layer between the first aerogel layer and the second aerogel layer.

[0136] The expansion layer may be formed by a coating method, a casting method, etc. Specifically, the expansion layer may be formed on the first aerogel layer of the first insulation sheet by a coating method, and the second aerogel layer of the second insulation sheet may be laminated on the expansion layer so as to face each other, and then the two sheets may be attached to each other to manufacture the insulation member.

[0137] In one embodiment, in the step of disposing the insulating member between the plurality of cells such that the upper and lower surfaces of the insulating member face the adjacent cells, the manner in which the plurality of cells are disposed is not specifically limited, and the insulating member may be disposed appropriately depending on the type of battery.

[0138] A heat insulating member may be disposed between each of the plurality of cells. Here, the first base material or the second base material of the heat insulating member may have an upper surface and a lower surface, and the upper surface and the lower surface may be disposed so as to face the adjacent cell.

[0139] An embodiment includes a battery pack including the battery module. A plurality of battery modules may be disposed within the battery pack.

[0140] 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 a person skilled in the art, the description thereof will be omitted.

[0141] (Battery module manufacturing) Example 1 1.Insulation material manufacturing Polyvinyl alcohol (Sigma Aldrich, Poly(vinyl alcohol)) was added as a binder to ultrapure water as a solvent, and then mixed under conditions of an open blade of 30 rpm and a despa blade of 700 rpm to produce a solvent mixture. 2 Aerogel mixture was prepared by adding aerogel having a particle size of 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 mixing 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.

[0142] The solid content of the prepared aerogel composition was confirmed to be 50 wt % aerogel, 40 wt % glass wool, and 10 wt % polyvinyl alcohol.

[0143] The aerogel composition prepared above was applied as a slurry onto a 0.3 mm thick mica sheet (Famica, Muscovite) to prepare a heat insulating sheet. Two such heat insulating sheets were prepared and used as a first heat insulating sheet and a second heat insulating sheet.

[0144] The first and second insulation sheets were placed with the aerogel composition-coated surfaces facing each other, and an expansion layer was formed between them by a coating method using a water-based thermally decomposable expansion coating liquid (Lord, Sipiol FR220), to manufacture an insulation member.

[0145] It was confirmed that the total thickness of the manufactured heat insulating member was 3 mm, and the thickness of the expansion layer was 0.3 mm.

[0146] 2. Battery module manufacturing A plurality of cells are arranged in a battery module, and a heat insulating member having an expansion layer formed thereon is arranged between each of the plurality of cells.

[0147] Example 2 The same method as in Example 1 was used to produce the expanded layer, except that the thickness of the expanded layer was 0.1 mm.

[0148] Example 3 The same method as in Example 1 was used to produce the expanded layer, except that the thickness of the expanded layer was 0.5 mm.

[0149] Example 4 The same method as in Example 1 was used to produce the expanded layer, except that the thickness of the expanded layer was 0.8 mm.

[0150] Example 5 The same method as in Example 1 was used to prepare the foam coating solution, in which a foaming material (UNICELL-5PT, Dongjin Semichem) and polyimide (PHOTONECE, Toray) were mixed in a ratio of 2:8.

[0151] Comparative Example 1 The manufacturing method was the same as that of Example 1, except that the expandable layer was not formed.

[0152] (Experimental Example) Experimental example 1: Thermal insulation evaluation The heat insulating members manufactured in Examples 1 to 5 and Comparative Example 1 were used to evaluate the heat insulating properties.

[0153] Specifically, each insulation sheet was placed between a pair of opposing 1T thick aluminum plates, which were then placed on a heat press, and the upper plate of the heat press was heated to 350°C, while the lower plate of the heat press was not heated and was kept at the starting temperature of 40°C. A pressure of 20kN was then applied to the lower plate of the heat press, and the maximum temperature of the lower plate of the heat press after 11 minutes was measured, and the results are shown in Table 1 below.

[0154] Experimental example 2: Compressibility evaluation The heat insulating members manufactured in Examples 1 to 5 and Comparative Example 1 were used to evaluate compression performance.

[0155] 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 Table 1 below.

[0156] Experimental Example 3: Expansion Evaluation 1. Expansion temperature The expansion temperatures of the expansion layers of the heat insulating members manufactured in Examples 1 to 5 and Comparative Example 1 were measured. Specifically, the expansion temperatures were measured by exposing the layers to a hot plate at intervals of 50°C, and the temperatures at which foaming was triggered were measured. The results are shown in Table 1 below.

[0157] 2. Length of outflow section after inflation The heat insulating members manufactured in Examples 1 to 5 and Comparative Example 1 were used to evaluate the expansion performance of the expansion layer.

[0158] Specifically, the temperature of the upper die in the UTM equipment was set to 800°C, and a load of 1.3 MPa was applied to each insulation material for 1 minute to compress it. The expansion layer expanded and flowed out from the side of the insulation material, and the average length of the expansion part formed by the expansion layer flowing out from the side of the insulation material and the thickness of the insulation material after compression were measured and are shown in Table 1 below.

[0159] Experimental example 4: Heat propagation evaluation The battery modules manufactured in Examples 1 to 5 and Comparative Example 1 were evaluated for flame propagation.

[0160] Specifically, the heat transfer was evaluated by a method of transferring heat under nail penetration conditions using a 50 Ah rectangular (NCM 811 / Graphite) 2-cell simplified module device with an upper cover attached and a gap between the top of the cell and the cover of 1.5 mm. The results are shown in Table 1 below.

[0161] [Table 1]

[0162] Referring to Table 1 above, it was confirmed that Examples 1 and 3 had excellent heat insulation, compressibility, and heat propagation prevention properties. On the other hand, it was confirmed that in Example 2, the expanded layer was formed thin, resulting in a small amount of outflow, and some heat propagation occurred. Also, in Example 4, it was confirmed that the expanded layer was formed thick, resulting in a decrease in the thickness of the insulating material after outflow, and heat propagation occurred due to a decrease in insulating performance. Also, in Example 5, it was confirmed that the expansion temperature of the internal expanded layer was high, resulting in less outflow compared to the heat transmitted inside the insulating sheet, and some heat propagation occurred.

[0163] On the other hand, in Comparative Example 1, which did not include an expansion layer, heat transfer could not be prevented at all.

[0164] Although the above describes preferred embodiments of the present invention, 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]

[0165] 100 cells 200 Insulation material 210 First insulation sheet 211 1st base material 212 First aerogel layer 220 Second insulation sheet 221 Second base material 222 Second aerogel layer 230 Expansion layer 231 Outflow 300 coating layers 1000 Battery Module

Claims

1. A plurality of cells; a heat insulating member provided between each of the plurality of cells, the upper surface and the lower surface of the heat insulating member being disposed so as to face the adjacent cell, The heat insulating member includes a first heat insulating sheet, a second heat insulating sheet, and an expansion layer formed between the first heat insulating sheet and the second heat insulating sheet.

2. The battery module according to claim 1 , wherein the cells are secondary battery cells.

3. The battery module according to claim 1 , wherein the first insulation sheet and the second insulation sheet each include a substrate and an aerogel layer formed on the substrate.

4. 4. The battery module according to claim 3, wherein the substrates of the first insulation sheet and the second insulation sheet face the adjacent cells, respectively, and the aerogel layers face the expansion layers, respectively.

5. The battery module according to claim 3 , wherein the base material of each of the first insulation sheet and the second insulation sheet is at least one selected from the group consisting of a resin, a metal, and an inorganic material other than a metal.

6. 4. The battery module according to claim 3, wherein the aerogel layers of the first insulation sheet and the second insulation sheet each include an aerogel, a fibrous support, and a functional material including a binder, a dispersant, or a combination thereof.

7. The aerogel has a BET specific surface area of ​​500 m ２ / g to 1,000m ２ The battery module according to claim 6, wherein the tensile strength is 1 / g.

8. 7. The battery module according to claim 6, wherein the fibrous support is at least one selected from the group consisting of natural fibers, silica fibers, glass fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

9. The battery module according to claim 6 , wherein the binder comprises a water-based polymer binder.

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

11. 7. The battery module according to claim 6, wherein the aerogel layer comprises, with respect to a total amount of the aerogel, 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.

12. 2. The battery module according to claim 1, wherein the expansion layer is at least one selected from the group consisting of a foaming material that expands when the ambient temperature increases to 100° C. to 200° C. and a flame-retardant material having a melting temperature of 60° C. to 100° C.

13. The foaming material is at least one selected from the group consisting of expanded graphite, organic foaming agents, and inorganic foaming agents; The organic foaming agent is at least one selected from the group consisting of azodicarbonamide, dinitropentamethylenetetramine, and oxybis(benzenesulfonylhydrazide); The battery module according to claim 12 , wherein the inorganic foaming agent is at least one selected from the group consisting of hydrogen carbonates, carbonates, and organic acid salts.

14. The battery module according to claim 12 , wherein the flame retardant material is at least one selected from the group consisting of polyurethane, polyvinyl chloride, and a polymer having a flame retardant dispersed therein.

15. The battery module according to claim 1 , wherein the thickness of the expansion layer is 1% to 30% of the total thickness of the insulating member.

16. 2. The battery module of claim 1, wherein when the expansion layer expands, the expansion layer flows out from a side surface of the insulating member to form an outflow portion, and a length of the outflow portion from the side surface of the insulating member is 500% to 3000% of a thickness of the expansion layer.

17. the battery module includes an empty space other than a space in which the cells and the insulating members are arranged, a coating layer formed to cover a side surface of the heat insulating member in an empty space formed under the battery module, The battery module according to claim 1 , wherein the coating layer comprises a flexible polymer.

18. The battery module according to claim 17 , 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.

19. manufacturing an insulating member; and disposing the heat insulating member between the plurality of cells such that an upper surface and a lower surface of the heat insulating member face adjacent cells, respectively; The insulating member includes a first insulating sheet, a second insulating sheet, and an expansion layer formed between the first insulating sheet and the second insulating sheet.

20. A battery pack comprising the battery module according to any one of claims 1 to 18.

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