Battery module, method of manufacturing same, and battery pack including same

Abstract

The invention relates to a battery module, a manufacturing method thereof and a battery pack comprising the battery module. The battery module comprises: a plurality of battery cells; an insulating sheet between the plurality of battery cells, the insulating sheet having an upper surface and a lower surface facing the battery cells adjacent thereto, respectively; and a foam layer formed on two or more side surface portions including the upper side surface portion of the boundary side surface between the upper surface and the lower surface of the insulating sheet. Example embodiments also include a method of manufacturing the battery module and a battery pack including the battery module.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0079352 filed on June 21, 2023 in the Korean Intellectual Property Office, and the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] Example embodiments relate to a battery module, a method of manufacturing the same, and a battery pack including the battery module. 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 generally rechargeable and are widely used in information technology (IT) devices (such as, for example, smart phones, mobile phones, laptops, 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 isolate and insulate adjacent battery cells from each other. Summary of the invention

[0007] Example embodiments include a battery module, a method of manufacturing a battery module, and a battery pack including a battery module having 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] An example embodiment includes a battery module, the battery module comprising: a plurality of battery cells; an insulating sheet located between the plurality of battery cells, the insulating sheet having an upper surface and a lower surface respectively facing the battery cells adjacent thereto; and a foam layer formed on two or more side surface portions including an upper side surface portion of a boundary side surface (hereinafter, also referred to as a "side surface") between the upper surface and the lower surface of the insulating sheet.

[0009] Each or one or more of the plurality of battery cells may be a secondary battery cell.

[0010] The insulating sheet may include: a first substrate; a second substrate; and an aerogel layer; located between the first substrate and the second substrate.

[0011] Each or one or more of the first substrate and the second substrate may be made of or include at least one of a resin, a metal, and an inorganic material other than a metal.

[0012] The aerogel layer may include at least one of an aerogel, a fiber support, and a functional material, wherein the functional material includes a binder, a dispersant, or a combination thereof.

[0013] 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.

[0014] The fibrous support may be or include at least one of natural fibers, silica fibers, glass fibers, ceramic fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers.

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

[0016] The dispersant may be or include at least one of a surfactant, a silane coupling agent, and a phosphate salt.

[0017] 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.

[0018] The foam layer may include a foam material configured to foam when the ambient temperature increases to a range of about 100°C to 200°C.

[0019] The foam layer may include a foaming agent including at least one of expanded graphite, an organic foaming agent, and an inorganic foaming agent.

[0020] The organic blowing agent may be or include at least one of azodicarbonamide, N,N′-dinitrosopentamethylenetetramine, and 4,4′-oxybis(benzenesulfonylhydrazide), and the inorganic blowing agent may be or include at least one of bicarbonate, carbonate, and a salt of an organic acid.

[0021] The thickness of the foam layer may be in the range of about 3% to 20% of the thickness of the insulation sheet.

[0022] The thickness of the foam layer after foaming may be in the range of about 1000% to 3000% of the thickness of the foam layer before foaming.

[0023] The foam layer may be formed on opposite side surface portions of the side surface of the insulation sheet facing upward and facing downward or on substantially the entire side surface of the insulation sheet.

[0024] The thickness of the foam layer formed on the upper side surface portion of the side surface of the insulation sheet may be at least about 100% of the thickness of the foam layer formed on the lower side surface portion of the side surface of the insulation sheet.

[0025] Another example embodiment includes a method for manufacturing a battery module, the method comprising: providing a plurality of battery cells; disposing an insulating sheet between the plurality of battery cells so that an upper surface and a lower surface of the insulating sheet respectively face the battery cells adjacent thereto; and forming a foam layer on two or more side surface portions including an upper side surface portion of a boundary side surface between the upper surface and the lower surface of the insulating sheet.

[0026] The foam layer may be formed before or after the insulating sheet is disposed between the plurality of battery cells.

[0027] Another example embodiment includes a battery pack including a battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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 stated numerical value. Moreover, when percentages are mentioned in this specification, it is intended that those percentages are based on weight, i.e., weight percentages. The expression "at most" includes an amount from zero to the expressed upper limit and all values ​​therebetween. When a range is specified, the range includes all values ​​therebetween, such as increments of 0.1%.

[0029] The attached drawings incorporated in this specification illustrate example embodiments and are used to further illustrate the technical concept of the present disclosure in conjunction with the detailed description of the following example embodiments, and the present disclosure is not to be construed as being limited to the contents shown in these drawings. In the drawings:

[0030] Figure 1 is a schematic diagram showing the structure of a battery module according to an example embodiment;

[0031] Figure 2 To show the basis after foaming Figure 1 A schematic diagram of a foam layer in a battery module of an example embodiment of the present invention; and

[0032] Figure 3 is a schematic diagram illustrating a cross-sectional structure of an insulation sheet according to an example embodiment. DETAILED DESCRIPTION

[0033] Hereinafter, example embodiments are 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.

[0034] A battery module according to an example embodiment may include: a plurality of battery cells; an insulating sheet provided between the plurality of battery cells, the insulating sheet respectively having an upper surface and a lower surface facing the battery cells adjacent thereto; and a foam layer located on two or more side surface portions including an upper side surface portion of a boundary side surface between the upper surface and the lower surface of the insulating sheet.

[0035] The battery module 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 a battery cell to a battery cell adjacent thereto due to thermal runaway of the battery. The insulating sheet 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, for example, external impact, thereby improving operability and reducing or preventing instrument contamination.

[0036] In example embodiments, the battery cell may be a secondary battery cell. The secondary battery cell may be or include, 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 interposed therebetween, and the positive electrode plate, the negative electrode plate, and the separator may be contained 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.

[0037] The secondary battery cell may require a substantially high degree of stability, for example, when overcharged, a positive electrode active material or an electrolyte may undergo decomposition and other side reactions, thereby possibly radiating heat from the secondary battery, resulting in explosion of the secondary battery cell.

[0038] In a battery module according to an example embodiment, an insulating sheet may be located between a plurality of battery cells, and a foam layer may be located at a side surface of the insulating sheet, whereby the battery module may have desired, advantageous or improved thermal insulation, fire resistance and flame retardancy or non-flammability, so that the propagation of heat and flame in a battery cell to a battery cell adjacent thereto due to thermal runaway of the battery cell may be reduced or suppressed.

[0039] Figure 1is a schematic diagram illustrating a battery module having an insulation sheet between a plurality of battery cells and a foam layer formed on a side surface of the insulation sheet according to an example embodiment.

[0040] refer to Figure 1 , a battery module 100 according to an example embodiment may include a plurality of battery cells 10 and may include an insulating sheet 20 between the plurality of battery cells 10. The insulating sheet 20 may be disposed so that the upper surface and the lower surface of the insulating sheet 20 respectively face the battery cells 10 adjacent thereto. The battery module 100 may further include a foam layer 30 formed on two or more side surface portions including the upper side surface portion of the side surface of the insulating sheet 20. Therefore, by pre-impeding or blocking the flame when thermal runaway occurs in one battery cell to substantially reduce or inhibit the flame from propagating to other battery cells, a battery module with increased safety may be provided, and further a secondary battery pack including the battery module may be provided.

[0041] Figure 2 It is a schematic diagram showing a foam layer that foams and spreads at a given temperature or higher.

[0042] refer to Figure 2 , a battery module 100 according to an example embodiment may include a plurality of battery cells 10, and may include an insulating sheet 20 between the plurality of battery cells 10, wherein a foam layer 30 may be formed on a side surface of the insulating sheet 20. When the ambient temperature increases to a given temperature or higher due to thermal runaway, the foam layer 30 may diffuse and fill a void area in the battery module 100 to reduce or prevent flame propagation.

[0043] In example embodiments, the insulating sheet may include: a first substrate; a second substrate; and an aerogel layer between the first and second substrates. The first and second substrates may form upper and lower surfaces of the insulating sheet, respectively, and may face battery cells adjacent thereto, respectively.

[0044] Figure 3 is a schematic diagram illustrating a structure of an insulation sheet according to an example embodiment.

[0045] refer to Figure 3 The insulating sheet 20 may be formed to have a structure including a first substrate 21, a second substrate 22, and an aerogel layer 23 between the first substrate 21 and the second substrate 22. The first substrate 21 and the second substrate 22 may form the upper and lower surfaces of the insulating sheet 20, respectively, and may face the adjacent substrates, respectively. Figure 1 and Figure 2 The battery cell 10 illustrated in FIG.

[0046] Each or one or more of the first substrate and the second substrate may be made of at least one of resin, metal and inorganic materials other than metal, or include but are not limited to at least one of resin, metal and inorganic materials other than metal, or may be made of or include a composite thereof. The form of the substrate may be, but is not limited to, a film, a membrane, a sheet, etc.

[0047] The resin may be, for example, at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide.

[0048] The metal may be, 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.

[0049] The inorganic material may be at least one of calcium carbonate (CaCO 3 ), talc, and mica.

[0050] As an example, each of the first substrate and the second substrate may include an inorganic material, and as a specific example, the substrate may include mica. In this case, thermal insulation, durability, etc. of the insulating sheet may be improved.

[0051] The aerogel layer may include at least one of an aerogel, a fiber support, and a functional material, wherein the functional material includes a binder, a dispersant, or a combination thereof.

[0052] Aerogels can have a thermal conductivity of about 500 m 2 / g~1,000m 2 / g range. For example, the aerogel may have a BET surface area of ​​about 500 m 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, dispersion of aerogel particles can be reduced or prevented, and thermal insulation can be improved.

[0053] The average particle size of the aerogel may be in the range of about 5 to 200 μm, 10 to 100 μm, or 20 to 60 μm. As the aerogel having a particle size in the above range is included, thermal insulation may be improved, thereby delaying heat transfer between a plurality of battery cells.

[0054] 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 having the above range is included, thermal insulation of the insulation sheet may be desirable, advantageous or may be improved.

[0055] Aerogel, as a transparent or translucent advanced material with a nanoporous structure, exhibits low density and low thermal conductivity, so aerogel is advantageous as an insulating material and is considered to be a highly efficient super insulating material that can be used in various industrial applications.

[0056] An important advantage of the aerogel of the example embodiments is that the aerogel has a lower thermal conductivity than conventional organic insulating materials (such as, for example, polystyrene foam), and the aerogel can solve or overcome the key weaknesses of organic insulating materials (such as, for example, fire vulnerability and harmful gases generated during fire). In various cases, the aerogel may be substantially brittle, easily broken under slight impact, and difficult to process into small thicknesses and shapes, making it difficult to manufacture thermal insulation materials using only aerogel despite having desired, advantageous or improved thermal insulation. In an example embodiment, a fibrous support and a functional material including a binder, a dispersant, or a combination thereof may be included to improve the durability of the aerogel layer and reduce or prevent dust generation during external impact or operation.

[0057] The fibrous support may be included in the aerogel layer, whereby the durability of an insulating sheet formed using the aerogel may be improved.

[0058] The fiber support may include fibers used as a support made of or including common insulating materials. For example, the fiber support may be at least one of natural fibers, silica fibers, glass fibers, ceramic fibers, carbon fibers, graphite fibers, mineral fibers, and polymer fibers. As an example, the fiber support may include, but is not limited to, glass fibers. As an example, glass fibers may include, but are not limited to, glass wool.

[0059] The natural fiber may be, for example, at least one of hemp, jute, flax, coir, kenaf, and cellulose.

[0060] The mineral fiber may be, for example, at least one of basalt, quartzite, alumina, silica, slag, and rock.

[0061] 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.

[0062] The fibrous support may be in the form of, for example, wool or chopped strands, but is not limited thereto.

[0063] The diameter 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 a diameter in the above range, the structure of the aerogel layer may be hardened and the manufacturing cost may be reduced.

[0064] 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 a fiber support within any of the above ranges is used to manufacture an insulating sheet, durability may be improved.

[0065] 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.

[0066] The water-based polymer may be, but is not limited to, at least one of polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinyl pyrrolidone.

[0067] 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 a polymer having a carboxylic acid group, and may include but is not limited to polymaleic acid as a specific example.

[0068] 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 a polymer having an amine group, and may be, but is not limited to, at least one of polyvinylamine and polyamine as a specific example.

[0069] The water-dispersible polymer may be, but is not limited to, at least one of a water-dispersible polyurethane and a water-dispersible polyester.

[0070] The binder may include at least one of a water-based polymer and a water-dispersible polymer. For example, the binder may include a water-based polymer having a bonding 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.

[0071] 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 any of the above ranges, in addition to the thermal insulation, dustiness, and compressibility of the insulation sheet, the fire resistance and mechanical properties of the insulation sheet may be further improved.

[0072] The binder may be contained 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. The insulating sheet including the aerogel layer including the binder within the above range may have improved dusting properties.

[0073] The dispersant may be 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.

[0074] Further inclusion of a dispersant can further improve the dispersion of the aerogel during fabrication of the aerogel layer, resulting in a substantially uniform dispersion of the fibrous support and the aerogel.

[0075] 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 any of the above ranges, the aerogel layer can be manufactured at a low cost and used to manufacture an insulation sheet having desired, advantageous, or improved thermal insulation, uniformity, and dust formation.

[0076] 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 the above range may result in aerogel being more uniformly dispersed in the aerogel layer.

[0077] 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.

[0078] 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 the above range, it is possible to achieve desired, advantageous or improved thermal insulation while improving durability, and the bonding between the fiber support and the aerogel may be improved, thereby reducing or preventing dust generation.

[0079] 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 %.

[0080] 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, advantageous or improved 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.

[0081] In example embodiments, the foam layer may include a foam material formed on two or more side surface portions including the upper side surface portion of the boundary side surface of the upper surface and the lower surface of the insulation sheet, the foam material being configured to foam when the ambient temperature increases to about 100° C. or higher. For example, the foam material may foam when the ambient temperature increases to a range of about 100° C. to 200° C., 120° C. to 180° C., or 120° C. to 170° C., and the thickness of the foam layer may increase due to an increase in its volume to fill a void area in the battery module, thereby reducing or preventing the spread of flames.

[0082] The foam layer may be formed on opposite side surface portions facing upward and downward of the side surface of the insulation sheet, or on substantially the entire side surface of the insulation sheet. "Upward" and "downward" may mean upward and downward directions based on the form in which the insulation sheet is disposed.

[0083] The insulating sheet may include an upper surface, a lower surface, and a boundary side surface between the upper surface and the lower surface. When the upper surface and the lower surface of the insulating sheet face the battery cells adjacent thereto, respectively, the boundary side surface of the insulating sheet may include an upper surface portion, a lower surface portion, a front surface portion, and a rear surface portion. The foam layer may be formed on the opposite side surface portions facing upward and downward of the side surface of the insulating sheet (i.e., the upper surface portion and the lower surface portion), or may be formed on substantially the entire side surface of the insulating sheet. As an example, the foam layer may be essentially formed on the upper surface portion of the boundary side surface of the insulating sheet. Wherein, the "upper surface portion" may mean a surface formed in an upward direction of the side surface portion based on the form in which the insulating sheet is arranged.

[0084] In the battery module, the foam layer may be formed to cover a portion or substantially the entire exposed portion of the surface of the insulation sheet that does not face the battery cell.

[0085] In the battery module, the foam layer may be formed to further cover a portion of or substantially the entire battery cell adjacent to the insulation sheet.

[0086] As an example, the foam layer may be formed on substantially the entire side surface of the insulating sheet. In this case, when thermal runaway occurs in one battery cell, the foam component may expand to fill the void area in the battery module in addition to the space where the battery cell, the insulating sheet, and the foam layer are located, thereby reducing or preventing the spread of flames.

[0087] As another example, the foam layer may be formed on the opposite side surface portions facing upward and downward of the side surface of the insulation sheet. In this case, the installation of the foam layer can be reduced or minimized while effectively reducing or preventing the spread of flames.

[0088] The foam layer may be formed to have a thickness corresponding to a range of about 3% to 20%, 5% to 15%, or 5% to 10% of the thickness of the insulating sheet (refer to Figure 1 By forming the foam layer to have a thickness within any one of the above ranges, the spread of flame can be reduced or prevented when thermal runaway occurs in one battery cell.

[0089] The thickness of the foam layer after foaming is in the range of about 1000% to 3000%, 1300% to 2500%, or 1700% to 2300% of the thickness of the foam layer before foaming. The foam layer can foam when the ambient temperature rises to a given temperature or higher, whereby the thickness of the foam layer after foaming can become in the range of about 10 to 30 times, 13 to 25 times, or 17 to 23 times the thickness of the foam layer before foaming.

[0090] In addition to the space in which the battery cell, the insulating sheet and the foam layer are disposed, the battery module may further include a void region therein, and the thickness of the foam layer after foaming may be equal to the height of the void region formed in the upper portion of the battery module (reference Figure 2 The thickness of the foam layer after foaming may be in the range of about at least 2 times, 2 times to 5 times, or 2 times to 4 times the height of the void area formed in the upper part of the battery module.

[0091] The thickness of the foam layer formed on the upper side surface portion of the side surface of the insulating sheet may be in the range of about at least 100%, 100% to 400%, 150% to 350%, or 200% to 350% of the thickness of the foam layer formed on the lower side surface portion of the side surface of the insulating sheet. The thickness of the foam layer formed on the upper side surface portion of the side surface of the insulating sheet may be in the range of about at least 1 times, 1 times to 4 times, 1.5 times to 3.5 times, or 2 times to 3.5 times the thickness of the foam layer formed on the lower side surface portion of the side surface of the insulating sheet. By controlling the ratio between the thickness of the foam layer formed on the upper side surface portion and the lower side surface portion of the side surface of the insulating sheet as described above, the spread of flames when thermal runaway occurs in a battery cell can be effectively reduced or prevented.

[0092] The foam layer may be made of or include a foam material, which foams and expands in volume when the ambient temperature increases to a range of about 100°C to 200°C, 120°C to 180°C or 120°C to 170°C, and the foam material may include a foaming agent, which includes, for example, at least one of expanded graphite, an organic foaming agent and an inorganic foaming agent.

[0093] The organic blowing agent may be or include at least one of azodicarbonamide (ADCA), N,N'-dinitrosopentamethylenetetramine (DPT) and 4,4'-oxybis(benzenesulfonylhydrazide) (OBSH). The inorganic blowing agent may be or include at least one of bicarbonate, carbonate and salt of organic acid.

[0094] The foam material may be mixed with a polymer material to form a coating solution. The polymer material may not be particularly limited as long as the polymer material can control the thickness of the foam layer after foaming and the foam triggering temperature of the foam material. For example, the polymer material may be at least one of polyimide, polyamide, polybenzimidazole, benzoxazole, polyamideimide, polyurethane, polyethylene terephthalate, polybutylene terephthalate, polyester, polyethylene (PE) and polypropylene (PP).

[0095] The coating solution including the foam material and the polymer material may foam and expand in volume when the ambient temperature increases to, for example, a range of about 100°C to 200°C, 120°C to 180°C, or 120°C to 170°C.

[0096] The foam material and the polymer material may form a coating solution in a weight ratio ranging from about 1:9 to 5:5, 1:9 to 4:6, or 1:9 to 3:7.

[0097] A method for manufacturing a battery module according to an example embodiment may include: providing a plurality of battery cells; disposing an insulating sheet between the plurality of battery cells so that an upper surface and a lower surface of the insulating sheet respectively face the battery cells adjacent thereto; and forming a foam layer on two or more side surface portions including an upper side surface portion of a boundary side surface between the upper surface and the lower surface of the insulating sheet.

[0098] In example embodiments, in providing the plurality of battery cells, a manner of providing the plurality of battery cells may not be particularly limited, and the plurality of battery cells may be appropriately provided according to the type of battery.

[0099] In example embodiments, the insulating sheet may be disposed between the plurality of battery cells. The insulating sheet may be disposed such that an upper surface and a lower surface of the insulating sheet face the battery cells adjacent thereto, respectively.

[0100] The insulating sheet may be prepared by forming a first substrate, applying the aerogel composition to the first substrate, and forming a second substrate on the applied aerogel composition.

[0101] The detailed description of each or one or more of the first and second substrates may be the same as described above, and the size and shape of each or one or more substrates may be appropriately adjusted according to the structure of the battery cell.

[0102] The aerogel composition may be prepared by mixing a solvent with a functional material including a binder, a dispersant, or a combination thereof to prepare a solvent mixture, mixing the solvent mixture with an aerogel to prepare an aerogel mixture, and mixing the aerogel mixture with a fibrous support to prepare the aerogel composition.

[0103] When the solvent is mixed with the functional material to prepare the solvent mixture, the solvent may be mixed with the binder, or the solvent may be mixed with the binder and the dispersant.

[0104] The solvent may be at least one of a polar solvent and a non-polar solvent.

[0105] The polar solvent may be at least one of water and an alcohol solvent.

[0106] The water may be, for example, at least one of purified water and deionized water.

[0107] The alcohol solvent may be, but is not limited to, at least one of methanol, ethanol, propanol, pentanol, butanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol and glycerol.

[0108] 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 is not limited to, an alkane solvent (such as hexane) or a mixture including an alkane solvent.

[0109] 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 easily mixed with hydrophobic aerogels. In example embodiments, the aerogels can be substantially uniformly dispersed by controlling the design of the mixing process, the mixing conditions, the addition of binders and dispersants, and the amounts of binders and dispersants. Substantially uniform dispersion of the aerogel in the composition can form an insulating sheet of a thin thickness with desired or improved thermal insulation, durability, and dust formation without using a large amount of binder.

[0110] 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 maintained compatible.

[0111] The detailed description of the binder and dispersant may be similar or the same as described above.

[0112] In mixing the solvent mixture with the aerogel to prepare the aerogel mixture, the detailed description of the aerogel may be similar or the same as described above.

[0113] In mixing the aerogel mixture with the fibrous support to prepare the aerogel composition, the detailed description of the fibrous support may be similar or identical to the above description.

[0114] In each of mixing the solvent with a functional material including a binder, a dispersant or a combination thereof to prepare a solvent mixture, mixing the solvent mixture with an aerogel to prepare an aerogel composition, and mixing the aerogel mixture with a fibrous support to prepare 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.

[0115] 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 result in the aerogel being substantially uniformly dispersed in the solvent.

[0116] A planetary mixer is a device that can be used to mix or stir different substances to produce a substantially homogenous mixture. A planetary mixer may include blades that are capable of planetary motion.

[0117] In an example embodiment, the planetary mixer may include at least one of one or more planetary blades and one or more high-speed dispersion blades. As another example, the planetary mixer may include at least one planetary blade and at least one high-speed dispersion blade.

[0118] Each of the planetary blades and the high-speed dispersion blades can be continuously rotated about its axis during operation. The rotation speed can be expressed in revolutions per minute (rpm).

[0119] 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.

[0120] The rotation speed of the first blade may be, for example, in the range of about 10-100 rpm, 10-60 rpm, or 30-70 rpm. The rotation speed of the second blade may be, for example, in the range of about 100-2000 rpm, 100-1000 rpm, 300-1700 rpm, or 500-1700 rpm.

[0121] 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 prepared to facilitate mixing of the aerogel in a subsequent process.

[0122] 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 uniform dispersion.

[0123] 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.

[0124] By forming an aerogel layer using the method according to example embodiments, thermal insulation and durability may be improved, and aerogel may be hindered or prevented from falling off and generating dust when an insulation sheet is manufactured or when the insulation sheet is installed in a device, or when external vibration occurs.

[0125] In example embodiments, a foam layer may be formed on two or more side surface portions including an upper side surface portion of a boundary side surface between an upper surface and a lower surface of the insulation sheet before or after disposing the insulation sheet between the plurality of battery cells.

[0126] As an example, the foam layer may be formed before the insulating sheet is disposed between the plurality of battery cells. In this case, after the insulating sheet is manufactured, the foam layer may be formed on two or more side surface portions of the side surface of the insulating sheet including the upper side surface portion, and the insulating sheet on which the foam layer is formed may be disposed between the plurality of battery cells.

[0127] The foam layer may be formed by coating, dipping, casting, etc. The foam layer may be formed by applying a solution including a foaming agent to two or more side surface portions including an upper side surface portion of the side surface of the insulation sheet and performing coating, dipping, or casting.

[0128] As another example, the foam layer may be formed after an insulating sheet is disposed between the plurality of battery cells. In this case, the insulating sheet may be disposed between the plurality of battery cells, and the foam layer may be formed on two or more side surface portions of the side surface of the insulating sheet including the upper side surface portion.

[0129] The foam layer may be formed by injection. By injecting a foaming agent or a solution including a foaming agent into a battery module in which a plurality of battery cells and an insulating sheet are arranged using a dispenser, an injector, etc., a foam layer may be formed on two or more side surface portions of the side surface of the insulating sheet including an upper side surface portion.

[0130] Example embodiments may include a battery pack including a battery module. A plurality of battery modules may be provided in the battery pack.

[0131] Hereinafter, examples will be described. However, the following examples are only intended 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 the details not described herein from a technical point of view, so their description will be omitted.

[0132] (Battery module manufacturing)

[0133] Example 1

[0134] 1. Manufacturing of insulation sheets

[0135] The mixture was prepared by adding polyvinyl alcohol (Sigma Aldrich) as a binder to deionized water as a solvent and stirring at 30 rpm using an open blade and Despa TM The solvent mixture was prepared by mixing it with a blade at 700 rpm. 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 stirring with an open blade at 30 rpm and using Despa TM The aerogel composition was prepared by mixing it with a blade at 1200 rpm. A planetary mixer (DNTEK, PT-005) was used for mixing.

[0136] The solid content of the prepared aerogel composition was found to be 50 wt % of aerogel, 40 wt % of glass wool and 10 wt % of polyvinyl alcohol.

[0137] The prepared aerogel composition slurry was applied to a 0.3 mm thick mica sheet (Famica TM , Muscovite TM), another 0.3 mm thick mica sheet was laminated thereon in a sandwich manner, and coating was performed using a rolling method.

[0138] It was found that the total thickness of the manufactured insulating sheet was 3 mm, the thickness of the aerogel layer was 2.4 mm, and the thickness of each mica sheet was 0.3 mm.

[0139] 2. Manufacturing of foam layer

[0140] An aqueous pyrolyzable intumescent coating solution (Lord, Sipiol FR220) as a solution including a foaming agent was applied to the entire side surface of the insulating sheet using a brush to form a foam layer. The thickness of the foam layer was found to be 0.15 mm.

[0141] 3. Manufacturing of battery modules

[0142] A plurality of battery cells are disposed in a battery module, and an insulating sheet having a foam layer is disposed between the plurality of battery cells.

[0143] Example 2

[0144] The battery module was produced using substantially the same method as in Example 1, except that the thickness of the foam layer was 0.25 mm.

[0145] Example 3

[0146] The battery module was produced using substantially the same method as in Example 1, except that the thickness of the foam layer was 0.1 mm.

[0147] Example 4

[0148] The battery module was made using substantially the same method as in Example 1, except that the thickness of the foam layer was 0.35 mm.

[0149] Example 5

[0150] The battery module uses substantially the same method as in Example 1, except that the foam layer is formed so that the thickness of the foam layer formed on the upper side surface portion of the side surface of the insulating sheet is 0.2 mm and the thickness of the foam layer formed on the other side surface portions of the side surface of the insulating sheet is 0.1 mm.

[0151] Example 6

[0152] The battery module uses substantially the same method as in Example 1, except that the foam layer is formed only on the upward and downward facing opposite side surface portions of the side surface of the insulating sheet (ie, the upper and lower side surface portions of the insulating sheet).

[0153] Comparative Example 1

[0154] The battery module was manufactured using substantially the same method as in Example 1, except that only aerogel was used to form the aerogel layer, and an insulating sheet without a foam layer was provided between the plurality of battery cells. In this case, the lack of a binder made it difficult to form the insulating sheet, and the effect of reducing or preventing heat propagation was not fully achieved.

[0155] Comparative Example 2

[0156] The battery module was formed using substantially the same method as in Example 1, except that the foam layer was not applied to the side surface of the insulating sheet but was formed on the upper and lower surfaces of the insulating sheet. The total thickness of the manufactured insulating sheet was the same as that of Example 1, and it was found that when the foam layer was formed on the upper and lower surfaces of the insulating sheet with a thickness of 0.15 mm, the thickness of the aerogel layer was 2.1 mm.

[0157] (Experimental example)

[0158] Experimental Example 1: Evaluation of the increase rate of foam layer thickness before and after foaming

[0159] The thickness increase rate of each foam layer produced in Examples 1 to 4 and Comparative Example 2 was evaluated.

[0160] For each insulating sheet on which a foam layer is formed, the thickness of the foam layer before foaming is measured. The upper and lower surfaces of the insulating sheet are fixed, heated for 3 minutes using a micro torch so that the foam layer is foamed, and the upward thickness of the foam layer after foaming is measured to calculate the upward thickness increase rate of the foam layer after foaming. Wherein, "upward thickness" may mean the thickness of the foam layer that expands in the upward direction based on the form in which the insulating sheet is set after foaming. The results are shown in Table 1 below.

[0161] Experimental Example 2: Evaluation of the properties of the insulation sheet

[0162] 1. Evaluation of thermal insulation

[0163] The thermal insulation of each of the insulating sheets manufactured in Examples 1 to 4 and Comparative Example 2 was evaluated. In Examples 1 to 4 and Comparative Example 2, the insulating sheet may refer to an insulating sheet on which a foam layer is formed.

[0164] 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 within 11 minutes was measured. The results are shown in Table 1 below.

[0165] 2. Evaluation of compressibility

[0166] The compressibility of each insulating sheet manufactured in Examples 1 to 4 and Comparative Example 2 was evaluated. In Examples 1 to 4 and Comparative Example 2, the insulating sheet may refer to an insulating sheet on which a foam layer is formed.

[0167] The ratio of the thickness when a load of 5 kN was applied using a universal testing machine (UTM) apparatus to the thickness when a load of 40 kN was applied using the UTM apparatus was measured. The results are shown in Table 1 below.

[0168] Experimental Example 3: Evaluation of Heat Propagation

[0169] Heat propagation of each of the battery modules manufactured in Examples 1 to 4 and Comparative Example 2 was evaluated.

[0170] Heat propagation evaluation was performed using a 50Ah prismatic (NCM 811 / graphite) 2-cell simple module assembly with a 1.5 mm gap between the top of each cell and the upper cover due to the upper cover being attached under nail penetration conditions. The results are shown in Table 1 below.

[0171] (Evaluation Criteria)

[0172] No: No fire occurred in any battery cell other than the battery cell penetrated by the nail.

[0173] Yes: Fire occurred in a battery cell other than the battery cell penetrated by the nail.

[0174] [Table 1]

[0175]

[0176] Referring to Table 1 above, it can be seen that in Comparative Example 2, the foam layer is formed only on the upper and lower surfaces of the insulating sheet, whereby the upward thickness increase of the foam layer after foaming is not significant, and the thickness of the aerogel layer is reduced under the condition that the total thickness of the insulating sheet is the same, whereby both thermal insulation and compressibility are reduced compared with Examples 1 to 4. In Examples 1 and 2, it can be seen that the foam layer is formed on the entire side surface of the insulating sheet and the thickness of the foam layer is controlled to be 5% to 10% of the total thickness of the insulating sheet, whereby the thickness increase rate of the upward thickness increase of the foam layer after foaming relative to the thickness of the foam layer is desirable, advantageous or improved, and thermal insulation, compressibility, fire resistance and flame retardancy are improved.

[0177] It can also be seen that even when the thickness of the foam layer on the lower surface portion of the side surface of the insulating sheet is slightly smaller than the thickness of the foam layer on the upper surface portion of the side surface of the insulating sheet (as in Example 5), or even when the foam layer is formed only on the upper surface portion and the lower surface portion of the side surface of the insulating sheet (as in Example 6), a sufficient effect of reducing or preventing heat propagation can be obtained.

[0178] Therefore, it can be seen that the battery module according to the example embodiment has a structure in which an insulating sheet is disposed between a plurality of battery cells and a foam layer is formed on a side surface of the insulating sheet, whereby thermal insulation, compressibility, and flame prevention effects are desirable, advantageous, or improved.

[0179] As apparent from the above description, a battery module according to example embodiments may reduce or suppress propagation of heat and flame in a battery cell to battery cells adjacent thereto due to thermal runaway of the battery cell.

[0180] The insulating sheet included in the battery module according to example embodiments may have desired, advantageous or improved thermal insulation, compressibility, mechanical strength and dimensional stability, thereby reducing or preventing the aerogel layer from falling off due to external impact, improving operability, and reducing or preventing instrument contamination.

[0181] 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. A battery module, comprising: Multiple battery cells; an insulating sheet located between the plurality of battery cells, the insulating sheet having an upper surface and a lower surface facing the battery cells adjacent thereto, respectively; as well as A foam layer is located on two or more side surface portions of a boundary side surface between the upper surface and the lower surface of the insulation sheet, including an upper side surface portion. 2 . The battery module according to claim 1 , wherein at least one of the plurality of battery cells is a secondary battery cell.

3. The battery module according to claim 1, wherein the insulating sheet comprises: a first substrate; a second substrate; as well as The aerogel layer is located between the first substrate and the second substrate. 4 . The battery module according to claim 3 , wherein at least one of the first substrate and the second substrate comprises at least one of a resin, a metal, and an inorganic material other than the metal. 5 . The battery module according to claim 3 , wherein the aerogel layer comprises at least one of an aerogel, a fiber support and a functional material, and the functional material comprises at least one of a binder and a dispersant.

6. The battery module according to claim 5, wherein the aerogel has a 2 / g~1,000m 2 / g range of BET specific surface area.

7. The battery module of claim 5, wherein the fiber support comprises at least one of natural fiber, silica fiber, glass fiber, ceramic fiber, carbon fiber, graphite fiber, mineral fiber and polymer fiber.

8. The battery module of claim 5, wherein the binder comprises an aqueous polymer binder. 9 . The battery module according to claim 5 , wherein the dispersant comprises at least one of a surfactant, a silane coupling agent and a phosphate salt.

10. The battery module of claim 5, wherein based on the total amount of the aerogel layer, the aerogel is included in a range of 10 wt% to 90 wt%, the fiber 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%. 11 . The battery module of claim 1 , wherein the foam layer comprises a foam material configured to foam when an ambient temperature increases to a range of 100° C. to 200° C. 12 . The battery module of claim 1 , wherein the foam layer comprises at least one of expanded graphite, an organic foaming agent, and an inorganic foaming agent.

13. The battery module according to claim 12, wherein The organic foaming agent comprises at least one of azodicarbonamide, N,N'-dinitrosopentamethylenetetramine and 4,4'-oxybis(benzenesulfonylhydrazide), and The inorganic foaming agent includes at least one of bicarbonate, carbonate and salt of an organic acid. 14 . The battery module according to claim 1 , wherein a thickness of the foam layer is in a range of 3% to 20% of a thickness of the insulating sheet. 15 . The battery module according to claim 1 , wherein a thickness of the foam layer after foaming is in a range of 1000% to 3000% of a thickness of the foam layer before foaming.

16. The battery module of claim 1, wherein the foam layer is formed on opposite side surface portions facing upward and downward of the boundary side surface of the insulation sheet, or the foam layer is formed on substantially the entire boundary side surface of the insulation sheet.

17. The battery module of claim 16, wherein a thickness of the foam layer formed on the upper surface portion of the boundary side surface of the insulation sheet is at least 100% of the thickness of the foam layer formed on the lower surface portion of the boundary side surface of the insulation sheet.

18. A method for manufacturing a battery module, the method comprising: Providing a plurality of battery cells; Disposing an insulating sheet between the plurality of battery cells so that the upper surface and the lower surface of the insulating sheet respectively face the battery cells adjacent thereto; as well as A foam layer is formed on two or more side surface portions of a boundary side surface between the upper surface and the lower surface of the insulation sheet, including an upper side surface portion. 19 . The method of claim 18 , wherein forming the foam layer is performed before or after disposing the insulating sheet between the plurality of battery cells.

20. A battery pack comprising the battery module according to any one of claims 1 to 17 or a battery module manufactured by the method according to claim 18 or 19.

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