Battery heat insulation sheet, method for manufacturing the same, and battery module including the same

Abstract

To provide a battery insulation sheet having at least one or more properties selected from properties such as excellent thermal insulation, heat resistance, low dust properties, and flexibility, a method of manufacturing the same, and a battery module including the same.SOLUTION: The battery insulation sheet includes an aerogel layer. The aerogel layer includes a fibrillized polymer matrix, and aerogel particles distributed in the fibrillized polymer matrix. The fibrillized polymer matrix includes a dry binder.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A secondary battery is a power storage system that provides excellent energy density capable of storing electrical energy in the form of chemical energy. Compared with a primary battery that cannot be recharged, a secondary battery can be recharged and is widely used in IT devices such as smartphones, cellular phones, notebook computers, and tablet PCs. In recent years, due to the prevention of environmental pollution, interest in electric vehicles has been increasing, and high-capacity secondary batteries are adopted in 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 large number of high-capacity cells such as lithium secondary batteries are included, if one cell undergoes thermal runaway due to overheating for some reason, it may have an adverse effect on other adjacent cells. Therefore, it is required that adjacent cells are thermally insulated from each other.

[0004] Therefore, conventionally, a plate material, an insulating resin plate, etc. are arranged between cells to achieve insulation and heat insulation between adjacent cells.

[0005] The above-described information disclosed in the technology that becomes the background of such an invention is only for improving the understanding of the background of the present invention, and thus may include information that does not constitute the prior art.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] One embodiment of the present invention aims to provide a battery heat insulation sheet having at least one or more properties selected from properties such as excellent heat insulation, heat resistance, low dust characteristics, and flexibility, a method for manufacturing the same, and a battery module including the same.

Means for Solving the Problems

[0008] One embodiment of the present invention is a battery heat insulation sheet including an aerogel layer, the aerogel layer including a fibrillated polymer matrix and aerogel particles distributed in the fibrillated polymer matrix, and the fibrillated polymer matrix including a dry binder, and provides a battery heat insulation sheet.

[0009] The dry binder includes a fluorine-based binder, and the fluorine-based binder may be one or more selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride-hexapropylene copolymer, and polyvinylidene fluoride.

[0010] With respect to the total amount of the aerogel layer, the fibrillated polymer matrix may be contained in an amount of 10% by weight or more and 90% by weight or less, and the aerogel particles may be contained in an amount of 10% by weight or more and 90% by weight or less.

[0011] The aerogel particles may have a BET specific surface area of 500 m 2 / g or more and 1,000 m 2 / g or less.

[0012] The average particle diameter (D50) of the aerogel particles may be 5 μm or more and 100 μm or less.

[0013] The aerogel particles may be dispersed inside the fibrillated polymer matrix.

[0014] The aerogel layer can satisfy the following formula (1). 0.1 ≦ W FB / TPM ≤18 ··· (1) In the above formula (1), W FB represents the content (% by weight) of the dry binder with respect to the total amount of the aerogel layer, and T PM represents the average particle diameter (μm) of the aerogel particles.

[0015] The battery heat insulation sheet may further include a base material provided on the upper surface, lower surface, or upper and lower surfaces of the aerogel layer.

[0016] The battery heat insulation sheet may have a structure in which a first base material, an aerogel layer, and a second base material are sequentially laminated.

[0017] Another embodiment provides a method for manufacturing a battery heat insulation sheet, including a step of manufacturing a raw material mixture containing a powdery dry binder and powdery aerogel particles, and a step of extruding the raw material mixture using an extruder to manufacture an aerogel layer, wherein the aerogel layer includes a fibrous polymer matrix in which aerogel particles are distributed, and the fibrous polymer matrix includes a fibrous dry binder.

[0018] The step of manufacturing the raw material mixture includes a primary dry mixing step and a secondary dry mixing step, and the stirring speed in the secondary dry mixing step may be 2 times or more the stirring speed in the primary dry mixing step.

[0019] In the primary dry mixing step, the temperature is 20°C or higher and 65°C or lower, the stirring speed is 2000 rpm or lower, and the stirring time is 5 minutes or more and 15 minutes or less. In the secondary dry mixing step, the temperature is 20°C or higher and 65°C or lower, the stirring speed is 4000 rpm or higher and 10,000 rpm or lower, and the stirring time is 10 minutes or more and 60 minutes or less.

[0020] The step of manufacturing the aerogel layer can include charging the raw material mixture into an extruder and extruding it into a sheet shape.

[0021] The step of manufacturing the aerogel layer may be performed under the conditions of a temperature of 25°C or higher and 150°C or lower and a pressure of 1 MPa or higher and 100 MPa or lower.

[0022] It may further include the step of laminating a substrate on the upper surface, lower surface, or both the upper and lower surfaces of the aerogel layer.

[0023] A first substrate and a second substrate can be laminated on the upper and lower surfaces of the aerogel layer, respectively.

[0024] Yet another embodiment provides a battery module including a plurality of cells and a battery heat insulation sheet provided between the plurality of cells, wherein the upper and lower surfaces of the battery heat insulation sheet are respectively arranged to face adjacent cells.

Advantages of the Invention

[0025] The battery heat insulation sheet according to an embodiment of the present invention includes a fibrous polymer matrix in which aerogels are distributed by a dry process using a heat-resistant dry binder and aerogels, and thus is excellent in heat insulation, heat resistance, low dust characteristics, and flexibility.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0027] Hereinafter, the embodiments will be described in detail so that those with ordinary knowledge in the technical field can easily implement them. However, the embodiments may be embodied in various different forms and are not limited to the embodiments described herein.

[0028] A heat insulating material is a material for preventing the flow of heat moving from a place with a high temperature to a place with a low temperature, and is used not only in refrigerators, cold storage warehouses, and buildings, but also in various industrial fields including aircraft, electronic components, and the automotive industry.

[0029] Such a heat insulating material should be provided with excellent heat insulating performance due to its low thermal conductivity, and mechanical strength for continuously maintaining such heat insulating properties is also required.

[0030] On the other hand, aerogel is a transparent or translucent advanced material with a nano-porous structure, has a very low density, and has the characteristic of low thermal conductivity. Therefore, it not only has high potential as a heat insulating material, but is also evaluated as a very efficient super heat insulating material that can be used in various industrial fields.

[0031] Moreover, the greatest advantage of aerogel is that it exhibits a lower thermal conductivity compared to conventional organic heat insulating materials such as styrofoam, and it can solve the problems of fire vulnerability, which is a fatal weakness of organic heat insulating materials, and the generation of harmful gases during a fire.

[0032] A battery heat insulating sheet according to an embodiment is a battery heat insulating sheet including an aerogel layer. The aerogel layer includes a fibrillated polymer matrix and aerogel particles distributed in the fibrillated polymer matrix, and the fibrillated polymer matrix may include a dry binder.

[0033] The battery heat insulation sheet formed by the structure can contain a high content of a dry binder having heat resistance. Therefore, in addition to heat insulation, heat resistance is also improved. The dry binder exists in a polymer matrix structure in which it is fiberized, and aerogel particles are dispersed inside the fiberized polymer matrix. Thus, it is rich in flexibility and can have low dust characteristics by preventing the detachment of the aerogel particles.

[0034] In particular, usually, the dry binder is excellent in heat resistance, but there is a limitation that its water dispersion is not relatively easy. However, the battery heat insulation sheet according to an embodiment of the present invention can contain a high content of the dry binder by a dry process without being affected by its dispersibility, and by making it easily contained in the heat insulation sheet, it can exhibit more excellent heat resistance. As a result, the target heat resistance can be achieved by a heat insulation sheet having a relatively thin thickness, and the phenomenon of aerogel particle detachment can be reduced.

[0035] In one embodiment, the fiberized polymer matrix may not contain an aqueous binder. Here, the aqueous binder can mean a normal water-soluble binder, and may include, for example, an inorganic binder, an aqueous polymer, an anionic water-soluble polymer, a cationic water-soluble polymer, and a water-dispersible polymer.

[0036] Specifically, the fiberized polymer matrix is manufactured by a dry process and may not contain an aqueous binder. By not containing the aqueous binder in this way, it is possible to form an aerogel layer having a structure in which aerogel is dispersed in the fiberized polymer matrix by extrusion in the dry process.

[0037] Incidentally, the inorganic binder may include soluble silicates, and can be understood to mean normal aqueous polymers such as sodium silicate, potassium silicate, and lithium silicate.

[0038] The aqueous polymer can mean ordinary aqueous polymers such as polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinylpyrrolidone.

[0039] The anionic water-soluble polymer can mean ordinary anionic water-soluble polymers such as polymers having functional groups of carboxylic acid, sulfonic acid, sulfate ester, phosphate ester, and salts thereof.

[0040] The cationic water-soluble polymer may include one or more 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 as a specific example, it can be understood to mean ordinary cationic water-soluble polymers such as polyethylene amine and polyamine.

[0041] The water-dispersible polymer can be understood to mean ordinary water-dispersible polymers such as water-dispersible polyurethane and water-dispersible polyester.

[0042] The dry binder may be, for example, a fibrillized binder. Specifically, the dry binder can be understood to mean a binder that can be fibrillized or a binder that has been fibrillized and can form a matrix.

[0043] The dry binder can mean a binder that is not impregnated, dissolved, and dispersed in a solvent. The dry binder is a fibrillized binder and can play a role of a matrix that supports and binds the aerogel. The aspect ratio of the dry binder may be 10 or more, 20 or more, 50 or more, or 100 or more.

[0044] The dry binder may contain one or more selected from the group consisting of, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride - hexapropylene (PVDF - HFP) copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, cellulose, polyvinylpyrrolidone, polyethylene, polypropylene, ethylene - propylene - diene polymer (EPDM), sulfonated - EPDM, styrene - butadiene rubber (SBR), and fluororubber, or may contain two or more copolymers, but is not limited thereto.

[0045] As a specific example, the dry binder can contain a fluorine - based binder. The fluorine - based binder can contain one or more selected from the group consisting of, for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride - hexapropylene (PVDF - HFP) copolymer, and polyvinylidene fluoride (PVDF). By including the dry binder, fibrillation can be achieved by a dry process. Specifically, in the dry process, a raw material mixture is extruded using an extruder to produce an aerogel layer. Here, when a water - based binder is included, it may be difficult to fibrillate the binder.

[0046] In one embodiment, the aerogel particles may have a BET specific surface area of 500 m 2 / g or more and 1,000 m 2 / g or less. For example, the aerogel particles may have a BET specific surface area of 500 m 2 / g or more and 950 m 2 / g or less, 550 m 2 / g or more and 950 m 2 / g or less, or 600 m 2 / g or more and 900 m 2 / g or less. By including aerogel particles having a BET specific surface area value within the range, heat transfer and heat propagation between a plurality of cells can be effectively prevented, and the heat insulation property of the battery heat insulation sheet can be improved.

[0047] The average particle size (D50) of the aerogel may be 5 μm or more and 100 μm or less, 10 μm or more and 100 μm or less, or 50 μm or more and 100 μm or less. By including aerogel particles having a particle size within the range, while preventing aggregation of aerogels and excessive thickness of the heat insulation sheet, the heat insulation property can be improved, and heat transfer between a plurality of cells can be delayed.

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

[0049] The aerogel particles may be dispersed inside a fibrous polymer matrix. Specifically, when forming an aerogel layer by the manufacturing method described later, the aerogel layer may be formed in a structure in which aerogel particles are uniformly dispersed inside a fibrous polymer matrix.

[0050] In one embodiment, with respect to the total amount of the aerogel layer, the fibrous polymer matrix may be contained in an amount of 10% by weight or more and 90% by weight or less, and the aerogel particles may be contained in an amount of 10% by weight or more and 90% by weight or less.

[0051] Specifically, the fibrous polymer matrix may be contained in an amount of 20% by weight or more and 90% by weight or less, 20% by weight or more and 75% by weight or less, or 20% by weight or more and 65% by weight or less with respect to the total amount of the aerogel layer, and the aerogel particles may be contained in an amount of 10% by weight or more and 80% by weight or less, 25% by weight or more and 80% by weight or less, or 35% by weight or more and 80% by weight or less. By controlling the contents of the fibrous polymer matrix and the aerogel particles in the aerogel layer within the range, a battery heat insulation sheet excellent in heat insulation property, heat resistance, flexibility, and low dust property can be provided.

[0052] In one embodiment, the content of the dry binder may be adjusted according to the size of the aerogel particles. Specifically, the aerogel layer can satisfy the following formula (1). 0.1 ≦ W FB / T PM ≦ 18 ··· (1) In the above formula (1), W FB represents the content (% by weight) of the dry binder with respect to the total amount of the aerogel layer, and T PM represents the average particle diameter (μm) of the aerogel particles.

[0053] Specifically, the W FB / T PM value may be 0.1 or more and 18 or less, 0.1 or more and 10 or less, 0.1 or more and 5 or less, or 0.2 or more and 1.3 or less. The W FB / T PM value can indicate the relationship between the average particle diameter of the aerogel particles and the content of the dry binder that can be included in the aerogel layer. For example, as the size of the aerogel particles increases, it becomes difficult to pack the dry binder in the fibrous matrix, and as the size of the aerogel particles decreases, the specific surface area becomes larger and an excessive amount of binder is required, so the heat insulation properties of the heat insulation sheet may deteriorate. Therefore, the aerogel particle size affects the content of the dry binder that can be included. Thus, by adjusting the W FB / T PM value within the above range, a battery heat insulation sheet excellent in heat insulation, heat resistance, flexibility, and low dust properties can be provided at a thin thickness.

[0054] The aerogel layer has a structure in which aerogel particles are uniformly distributed inside a polymer matrix fibrillated by the manufacturing method described later. Since the aerogel layer does not have many empty spaces inside, even if it is formed with a thin thickness, it is rich in heat insulation properties and can contain a dry binder with high heat resistance in a high content, and can have excellent heat resistance. Also, the aerogel particles are uniformly distributed inside the fibrillated polymer matrix, and it is possible to prevent the generation of dust due to the desorption of the aerogel particles. Also, while the empty space inside the aerogel layer functions to absorb vibration and impact, it causes an increase in the thickness of the heat insulation sheet. However, in the battery heat insulation sheet according to one embodiment, even if the aerogel layer does not have many empty spaces inside, excellent flexibility can be realized by the fibrillated polymer matrix, so it can be used as a heat insulation sheet for various forms of batteries. In particular, even when applied to an environment where the battery moves without being fixed during driving, such as an electric vehicle, it is possible to prevent the desorption of the aerogel particles.

[0055] The thickness of the aerogel layer may be 1 mm or more and 10 mm or less, 1 mm or more and 5 mm or less, or 1 mm or more and 3 mm or less. By forming the aerogel layer on a substrate having a thickness within the range, a heat insulation sheet having excellent heat insulation properties, heat resistance, flexibility, and low dust characteristics with a thin thickness can be manufactured.

[0056] In one embodiment, the battery heat insulation sheet may further include a substrate provided on the upper surface, lower surface, or upper and lower surfaces of the aerogel layer.

[0057] As an example, FIG. 1 is a schematic diagram showing the structure of a battery heat insulation sheet according to one embodiment.

[0058] Referring to FIG. 1, the battery heat insulation sheet 100 includes an aerogel layer 110. Here, the upper and lower surfaces of the aerogel layer 110 may be arranged to face adjacent cells, respectively.

[0059] As another example, FIG. 2 is a schematic diagram showing the structure of a battery heat insulation sheet according to one embodiment.

[0060] Referring to FIG. 2, the battery heat insulation sheet 100 includes a base material 120 and an aerogel layer 110 formed on the base material 120. Here, the upper surface of the battery heat insulation sheet, for example, the upper surface of the aerogel layer 110 and the lower surface of the base material 120 may be respectively arranged to face the adjacent cells.

[0061] As yet another example, FIG. 3 is a schematic diagram showing the structure of a battery heat insulation sheet according to an embodiment.

[0062] Referring to FIG. 3, in one embodiment, the battery heat insulation sheet 100 may have a structure including a first base material 130, an aerogel layer 110 formed on the first base material 130, and a second base material 140 formed on the aerogel layer 110. Specifically, the battery heat insulation sheet may have a structure in which the first base material 130, the aerogel layer 110, and the second base material 140 are sequentially laminated. Here, the first base material 130 and the second base material 140 may be respectively arranged to face the adjacent cells. The first base material 130 and the second base material 140 may be formed of the same or different materials from each other.

[0063] The base material may include a resin, a metal, an inorganic material other than a metal, or a composite thereof, without limiting its type. Also, the form of the base material is not particularly limited, such as a film, a thin film, a sheet, etc. Here, the base material can mean the base material 120 in FIG. 2, the first base material 130 in FIG. 2, and the second base material 140.

[0064] The resin may include, for example, one or more selected from the group consisting of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyamide.

[0065] The metal may include, for example, one or more selected from the group consisting of copper, nickel, cobalt, iron, chromium, vanadium, palladium, ruthenium, rhodium, molybdenum, tungsten, iridium, silver, gold, and platinum. When using a base material of a metal material, the base material may be subjected to corrosion prevention treatment, insulation treatment, etc. as required.

[0066] The inorganic material may include one or more selected from the group consisting of calcium carbonate (CaCO3), talc, and mica.

[0067] As a specific example, the substrate may include an inorganic material, and more specifically, may include mica. In this case, the heat insulation property and durability of the heat insulation sheet can be improved.

[0068] The thickness of the substrate may be 0.01 mm or more and 5 mm or less, 0.05 mm or more and 3 mm or less, or 0.1 mm or more and 1 mm or less. By including a substrate having a thickness within the range, the durability of the battery heat insulation sheet can be improved.

[0069] A method for manufacturing a battery heat insulation sheet according to an embodiment includes a step of manufacturing a raw material mixture including a powdery dry binder and powdery aerogel particles, and a step of extruding the raw material mixture using an extruder to manufacture an aerogel layer. The aerogel layer includes a fibrillated polymer matrix in which aerogel particles are distributed, and the fibrillated polymer matrix may include a dry binder.

[0070] The method for manufacturing a battery heat insulation sheet may be performed entirely by a dry process, and the specific description of the components of the aerogel layer may be as described above.

[0071] In the step of manufacturing a raw material mixture including a powdery dry binder and powdery aerogel particles, the specific description of the dry binder and aerogel particles may be as described above.

[0072] In the step of manufacturing the raw material mixture, the dry binder and aerogel particles may be mixed in powder form without containing a solvent.

[0073] The step of manufacturing the raw material mixture may be carried out by one or more than two mixing steps. Specifically, the step of manufacturing the raw material mixture includes a primary dry mixing step and a secondary dry mixing step, and the stirring speed in the secondary dry mixing step may be two times or more, two times or more and eight times or less, or four times or more and six times or less of the stirring speed in the primary dry mixing step.

[0074] In the primary dry mixing step, the temperature is 20°C or more and 65°C or less, 25°C or more and 50°C or less, or 25°C or more and 35°C or less, the stirring speed is 2000 rpm or less, 500 rpm or more and 1800 rpm or less, or 800 rpm or more and 1300 rpm or less, and the stirring time may be 5 minutes or more and 15 minutes or less.

[0075] In the secondary dry mixing step, the temperature is 20°C or more and 65°C or less, 25°C or more and 50°C or less, or 25°C or more and 35°C or less, the stirring speed is 4000 rpm or more and 10,000 rpm or less, 4000 rpm or more and 8000 rpm or less, or 4000 rpm or more and 6000 rpm or less, and the stirring time may be 10 minutes or more and 60 minutes or less, 10 minutes or more and 40 minutes or less, or 20 minutes or more and 30 minutes or less.

[0076] By extruding the raw material mixture that has undergone the primary and secondary dry mixing steps under the above conditions, an aerogel layer in which aerogel particles are distributed inside the fibrous polymer matrix can be formed.

[0077] In the step of manufacturing the raw material mixture, a stirrer can be used during stirring. The stirrer may include, for example, a kneader. The stirrer may have a structure including, for example, a chamber, one or more rotating shafts disposed inside the chamber and rotating, and blades rotatably coupled to the rotating shafts and disposed in the longitudinal direction of the rotating shafts. The blades may include, for example, one or more selected from a ribbon blade, a sigma blade, a jet (Z) blade, a dispersion blade, and a screw blade. By including the blades, the aerogel and the dry binder can be effectively mixed without a solvent to produce a dough-like raw material mixture.

[0078] When manufacturing the raw material mixture, based on the total amount of the raw material mixture, the dry binder may be contained in an amount of 20% by weight or more and 70% by weight or less, 30% by weight or more and 60% by weight or less, or 40% by weight or more and 60% by weight or less, and the aerogel particles may be contained in an amount of 30% by weight or more and 80% by weight or less, 40% by weight or more and 70% by weight or less, or 40% by weight or more and 60% by weight or less. When manufacturing the raw material mixture within the range, an aerogel layer excellent in heat insulation, heat resistance, flexibility, and low dust characteristics can be manufactured.

[0079] In one embodiment, the step of manufacturing the aerogel layer may be to put the raw material mixture into an extruder and extrude it into a sheet shape.

[0080] The step of manufacturing the aerogel layer can be carried out at a temperature of 25°C or more and 150°C or less, 30°C or more and 100°C or less, or 30°C or more and 70°C or less. Also, in the step of manufacturing the aerogel layer, the pressure during extrusion may be 1 MPa or more and 100 MPa or less, 20 MPa or more and 80 MPa or less, or 30 MPa or more and 70 MPa or less. By extruding the raw material mixture under these conditions, an aerogel layer having a structure in which aerogel is uniformly distributed in the dry binder can be formed.

[0081] The manufacturing method of the battery heat insulation sheet according to one embodiment is carried out by a dry process, and since it does not contain a process solvent, there is an advantage that an additional process for removing residual solvent is unnecessary.

[0082] In one embodiment, when radiating the raw material mixture with an extruder in the step of manufacturing the aerogel layer, the temperature may be 20°C or more and 90°C or less, 30°C or more and 60°C or less, or 35°C or more and 55°C or less. Also, the pressure during radiation may be 30 MPa or more and 70 MPa or less, 40 MPa or more and 65 MPa or less, or 40 MPa or more and 60 MPa or less. By radiating the raw material mixture under the conditions within the range, an aerogel layer containing a fibrillated polymer matrix in which aerogel is dispersed can be manufactured.

[0083] An extruder can be a normal extruder and is not particularly limited. For example, a single-screw extruder and a twin-screw extruder can be used.

[0084] In one embodiment, it may further include the step of laminating a substrate on the upper surface, lower surface, or both the upper and lower surfaces of the aerogel layer. As an example, the aerogel layer can be laminated on a substrate to manufacture a battery heat insulation sheet. As another example, a first substrate and a second substrate can be laminated on the upper and lower surfaces of the aerogel layer respectively to manufacture a battery heat insulation sheet. Here, the specific descriptions of the substrate, the first substrate, and the second substrate can be as described above.

[0085] The step of laminating the substrate can laminate the substrate on the upper surface, lower surface, or both the upper and lower surfaces of the aerogel layer using an adhesive. Specifically, the step of laminating the substrate can be performed by coating an adhesive layer on the upper surface, lower surface, or both the upper and lower surfaces of the aerogel layer using a normal adhesive and then laminating the substrate on the adhesive layer.

[0086] A battery module according to one embodiment includes a plurality of cells and a battery heat insulation sheet provided between the plurality of cells respectively. The upper and lower surfaces of the battery heat insulation sheet may be arranged to face the adjacent cells respectively.

[0087] FIG. 4 is a schematic diagram showing a battery heat insulation sheet according to one embodiment formed between a plurality of cells.

[0088] Referring to FIG. 4, a battery heat insulation sheet 100 according to an embodiment may be formed between respective cells 200 within a battery module including a plurality of cells 200. Here, the battery heat insulation sheet 100 may include an upper surface, a lower surface, and an edge side surface between the upper surface and the lower surface. The upper and lower surfaces of the battery heat insulation sheet 100, that is, the upper surface and the lower surface, may be arranged to face respective adjacent cells 200. For example, the upper and lower surfaces of the aerogel layer 110 in FIG. 1 described above may be respectively arranged to face respective cells 200 formed on the left and right in FIG. 4. As another example, the upper surface of the aerogel layer 110 and the lower surface of the base material 120 in FIG. 2 described above may be respectively arranged to face respective cells 200 formed on the left and right in FIG. 4. As yet another example, the lower surface of the first base material 130 and the upper surface of the second base material 140 in FIG. 3 described above may be respectively arranged to face respective cells 200 formed on the left and right in FIG. 4. By forming the battery heat insulation sheet 100 according to the above embodiment between respective cells 200, it is possible to suppress as much as possible the propagation of a flame to other cells by blocking the flame inside the cell in advance, and to provide a battery module with higher safety and a battery pack including the same.

Example

[0089] Specific examples of the present invention are presented below. However, the examples described below are merely for specifically exemplifying or explaining the present invention, and the present invention should not be limited thereto. Also, since those skilled in the art of this technology can technically make sufficient analogies for the content not described herein, the description thereof is omitted.

[0090] (Manufacture of Battery Heat Insulation Sheet) Example 1 1. Manufacture of Raw Material Mixture As a dry binder, powdered polytetrafluoroethylene and aerogel particles (D50 50 μm) were mixed to produce a raw material mixture. The raw material mixture was first dry-mixed at 25°C for 10 minutes at a stirring speed of 1000 rpm to produce a first mixture. Subsequently, the first mixture was further mixed at 25°C for 20 minutes at a stirring speed of 5000 rpm to produce a second mixture.

[0091] Here, with respect to the total amount of the raw material mixture, the content of polytetrafluoroethylene is 50% by weight, and the content of aerogel particles is 50% by weight.

[0092] 2. Manufacture of Aerogel Layer The prepared second mixture was put into an extruder and extruded under a pressure condition of 50 MPa at a temperature condition of 45°C to form an aerogel layer in which aerogel particles were distributed inside the fibrous polytetrafluoroethylene matrix. Here, the thickness of the aerogel layer was confirmed to be 2 mm.

[0093] 3. Manufacture of Battery Heat Insulation Sheet On the upper and lower surfaces of the aerogel layer, mica sheets (Famica, Muscovite) with a thickness of 0.1 mm were laminated by a coating method using an adhesive to produce a battery heat insulation sheet.

[0094] Example 2 The same method as in Example 1 was carried out, except that in Example 1, the raw material mixture had a composition of 20% by weight of polytetrafluoroethylene and 80% by weight of aerogel particles.

[0095] Example 3 The same method as in Example 1 was carried out, except that in Example 1, the raw material mixture had a composition of 35% by weight of polytetrafluoroethylene and 65% by weight of aerogel particles.

[0096] Example 4 The same method as in Example 1 was carried out, except that in Example 1, the raw material mixture had a composition of 65% by weight of polytetrafluoroethylene and 35% by weight of aerogel particles.

[0097] Example 5 The procedure of Example 1 was repeated, except that aerogel particles with an average particle size (D50) of 5 μm were used and the raw material mixture had a composition of 80 wt% polytetrafluoroethylene and 20 wt% aerogel particles.

[0098] Example 6 The procedure of Example 1 was repeated, except that aerogel particles with an average particle size (D50) of 100 μm were used.

[0099] Comparative Example 1 1. Manufacture of Aerogel Composition An aerogel composition was produced by adding and mixing polyvinyl alcohol (Sigma Aldrich, Poly(vinyl alcohol)) as an aqueous binder, polytetrafluoroethylene as a dry binder, and aerogel particles into an ultrapure water solvent.

[0100] The solid content of the aerogel composition was confirmed to be 85 wt% aerogel, 10 wt% polyvinyl alcohol, and 5 wt% polytetrafluoroethylene.

[0101] 2. Manufacture of Battery Heat Insulation Sheet The aerogel composition produced on a mica sheet (Famica, Muscovite) with a thickness of 0.1 mm was applied as a slurry, and then a mica sheet with a thickness of 0.1 mm was laminated in a sandwich type and coated by a roll rolling method. Then, it was dried to form an aerogel layer, and a battery heat insulation sheet was produced.

[0102] Comparative Example 2 The procedure of Comparative Example 1 was repeated, except that the amount of raw materials charged during the production of the aerogel composition was adjusted to produce an aerogel composition with a solid content of 50 wt% aerogel and 50 wt% polytetrafluoroethylene. In this case, since it was difficult to disperse polytetrafluoroethylene, a battery heat insulation sheet could not be produced.

[0103] Comparative Example 3 In Comparative Example 1, during the production of the aerogel composition, the input amount of the raw materials was adjusted, and the aerogel composition was produced in the same manner as in Comparative Example 1 except that the solid content was 85% by weight of aerogel, 5% by weight of polyvinyl alcohol, and 10% by weight of polytetrafluoroethylene. Also in this case, the dispersion of polytetrafluoroethylene was difficult, and a battery heat insulating sheet could not be produced.

[0104] (Experimental Example) Experimental Example 1: Heat Insulation Property Evaluation Using the battery heat insulating sheets produced in Examples 1 to 6 and Comparative Examples 1 to 3, the heat insulation property was evaluated by the following method, and the results are shown in Table 1 below.

[0105] Normal temperature (23 ± 5°C) thermal conductivity (mW / mK): The heat insulating sheet was cut into a width of 125 mm to 150 mm and a width of 125 mm to 150 mm to produce test pieces, and the normal temperature (23 ± 5°C) thermal conductivity was measured using an HFM436 Lambda equipment manufactured by NETZSCH. A lower normal temperature thermal conductivity means better heat insulation property of the heat insulating sheet.

[0106] Experimental Example 2: Dustiness Evaluation Using the battery heat insulating sheets produced in Examples 1 to 6 and Comparative Examples 1 to 3, the dustiness was evaluated by the following method, and the results are shown in Table 1 below.

[0107] Dustiness test: Using a vibration testing machine (ASTM C592 - 04), with vibration conditions of 24 Hz / 3 mm and 6 hours, the weight reduction rate due to vibration was measured. - Sample preparation: Prepare a 12 × 12 inch heat insulating sheet - Weight reduction rate [%]=[(weight of the heat insulating sheet before evaluation)-(weight of the heat insulating sheet after evaluation)] / (weight of the heat insulating sheet before evaluation)×100

[0108] Experimental Example 3: Flexibility Evaluation Using the battery heat insulating sheets produced in Examples 1 to 6 and Comparative Examples 1 to 3, the flexural modulus was evaluated, and the results are shown in Table 1 below.

[0109] Flexural modulus (Mpa): Each heat insulation sheet was manufactured as a test piece based on the ASTM D790 standard and measured using a UTM (UT-005E) manufactured by MTDI. Specifically, by the three-point bending analysis method, the manufactured test piece was placed on a support table, a force was applied to the center of the test piece at a speed of 1 mm / min to 10 mm / min, the load was recorded, and the initial gradient value obtained by dividing this by the 15% strain was measured to measure the flexural modulus at a 15% strain. A lower flexural modulus means that the heat insulation sheet has better flexibility.

[0110]

Table 1

[0111] From Table 1 above, it was confirmed that in the examples, the heat insulation, dustiness, and flexibility were all excellent. Also, it can be expected that it contains a high content of a heat-resistant binder and is excellent in heat resistance.

[0112] Here, from Examples 1 to 6, it was confirmed that the changes in heat insulation, dustiness, and flexibility due to the contents of aerogel particles and polytetrafluoroethylene. Specifically, when the average particle size of the aerogel particles is 50 μm or more and 100 μm or less, and the content of polytetrafluoroethylene is 20% by weight or more and 65% by weight or less, it was confirmed that better physical property measurement results are shown.

[0113] On the other hand, it was confirmed that when the aerogel layer was formed in a wet process using a solvent in Comparative Example 1, although the content of aerogel particles was higher than that in Example 2, the heat insulation property was at a similar level, and the flexibility and dustiness were also reduced. Further, as can be confirmed from Comparative Examples 1 to 3, when manufacturing the aerogel layer in a wet process, polytetrafluoroethylene can only be contained up to 5% by weight at most. When exceeding this amount, it can be seen that it is difficult to form the aerogel layer due to the dispersibility problem. Also, it was confirmed that when forming the aerogel layer by a wet process, it is difficult to manufacture the battery heat insulation sheet with a thin thickness as in the examples.

[0114] Therefore, it was confirmed that when using the aerogel composition according to one embodiment, it is excellent in heat insulation property, heat resistance, flexibility, and low dust property.

[0115] As described above, the preferred embodiments of the present invention have been explained. However, the present invention is not limited thereto, and various modifications can be made and implemented within the scope of the claims, the detailed description of the invention, and the attached drawings, and it goes without saying that those also belong to the scope of the present invention.

Explanation of Reference Numerals

[0116] 100 Battery heat insulation sheet 110 Aerogel layer 120 Base material 130 First base material 140 Second base material 200 Cell

Claims

1. A battery heat insulation sheet including an aerogel layer, wherein the aerogel layer includes a fibrillated polymer matrix and aerogel particles distributed in the fibrillated polymer matrix, the fibrillated polymer matrix includes a dry binder, the aerogel particles have a BET specific surface area of 500 m2 / g or more and 1,000 m2 / g or less, the aerogel layer satisfies the following formula (1), and is a battery heat insulation sheet. 0.1 ≦ WF B / T PM ≦ 18... (1) In the above formula (1), WF B represents the content (wt%) of the dry binder with respect to the total amount of the aerogel layer, and T PM represents the average particle diameter (μm) of the aerogel particles.

2. The dry binder includes a fluorine-based binder, and the fluorine-based binder is one or more selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride-hexapropylene copolymer, and polyvinylidene fluoride. The battery heat insulation sheet according to Claim 1.

3. With respect to the total amount of the aerogel layer, the fibrillated polymer matrix is included in an amount of 10 wt% or more and 90 wt% or less, and the aerogel particles are included in an amount of 10 wt% or more and 90 wt% or less. The battery heat insulation sheet according to Claim 1.

4. The average particle diameter (D50) of the aerogel particles is 5 μm or more and 100 μm or less. The battery heat insulation sheet according to Claim 1.

5. The aerogel particles are dispersed inside the fibrillated polymer matrix. The battery heat insulation sheet according to Claim 1.

6. The battery heat insulation sheet further includes a base material provided on the upper surface, lower surface, or upper and lower surfaces of the aerogel layer. The battery heat insulation sheet according to Claim 1.

7. The battery heat insulation sheet has a structure in which a first base material, the aerogel layer, and a second base material are sequentially laminated. The battery heat insulation sheet according to Claim 6.

8. Manufacturing a raw material mixture including a powdery dry binder and powdery aerogel particles; Extruding the raw material mixture using an extruder to manufacture an aerogel layer, wherein the aerogel layer includes a fibrillated polymer matrix in which aerogel particles are distributed, and the fibrillated polymer matrix includes a dry binder. The aerogel particles have a BET specific surface area of 500 m2 / g or more and 1,000 m2 / g or less, The method for manufacturing a battery heat insulation sheet, wherein the aerogel layer satisfies the following formula (1). 0.1 ≦ WF B / T PM ≦ 18... (1) In the above formula (1), WF B represents the content (% by weight) of the dry binder with respect to the total amount of the aerogel layer, and T PM represents the average particle diameter (μm) of the aerogel particles.

9. The method for manufacturing a battery heat insulation sheet according to claim 8, wherein the step of manufacturing the raw material mixture is performed by a primary or secondary or higher dry mixing step.

10. The method for manufacturing a battery heat insulation sheet according to claim 8, wherein the step of manufacturing the raw material mixture includes a primary dry mixing step and a secondary dry mixing step, and the stirring speed in the secondary dry mixing step is 2 times or more the stirring speed in the primary dry mixing step.

11. In the primary dry mixing step, the temperature is 20°C or more and 65°C or less, the stirring speed is 2,000 rpm or less, and the stirring time is 5 minutes or more and 15 minutes or less. In the secondary dry mixing step, the temperature is 20°C or more and 65°C or less, the stirring speed is 4,000 rpm or more and 10,000 rpm or less, and the stirring time is 10 minutes or more and 60 minutes or less. The method for manufacturing a battery heat insulation sheet according to claim 10.

12. The method for manufacturing a battery heat insulation sheet according to claim 8, wherein in the step of manufacturing the aerogel layer, the raw material mixture is put into the extruder and extruded into a sheet shape.

13. The method for manufacturing a battery heat insulation sheet according to claim 8, wherein the step of manufacturing the aerogel layer is performed under the conditions of a temperature of 25°C or more and 150°C or less and a pressure of 1 MPa or more and 100 MPa or less.

14. The method for manufacturing a battery heat insulation sheet according to claim 8, further including a step of laminating a base material on the upper surface, lower surface, or upper and lower surfaces of the aerogel layer.

15. The method for manufacturing a battery heat insulation sheet according to claim 8, wherein a first base material and a second base material are laminated on the upper and lower surfaces of the aerogel layer, respectively.

16. A plurality of cells, A battery heat insulation sheet according to any one of claims 1 to 7 provided between the plurality of cells, and A battery module in which the upper and lower surfaces of the battery heat insulation sheet are respectively arranged so as to face adjacent cells.

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