Aerogel composition for battery insulation sheet, battery insulation sheet using same, and method for manufacturing same

Abstract

The present invention relates to an aerogel composition for a battery insulation sheet, a battery insulation sheet using same, and a method for manufacturing same. The aerogel composition for a battery insulation sheet includes heat-resistant fibers, aerogel, and a binder to secure heat insulation and heat resistance, and at the same time, has flexibility, thereby preventing peeling and improving durability. In addition, the battery insulation sheet according to one embodiment of the present invention can improve flexibility and coatability by using a substrate including heat-resistant fibers.

Description

Aerogel composition for battery insulation sheets, battery insulation sheet using the same, and method for manufacturing the same

[0001] The present invention claims the benefit of the filing date of Patent Application No. 10-2025-0025724 filed with the Korean Intellectual Property Office on February 27, 2025, and the entire contents thereof are incorporated into the present invention.

[0002] The present invention relates to an aerogel composition for a battery insulation sheet, a battery insulation sheet using the same, and a method for manufacturing the same. Specifically, the invention relates to an aerogel composition for a battery insulation sheet comprising heat-resistant fibers and an aerogel to ensure thermal insulation and heat resistance, while simultaneously providing flexibility to prevent delamination and improve durability, a battery insulation sheet using the same, and a method for manufacturing the same.

[0003] Globally, the electric and power industry is rapidly expanding due to the efficiency of rechargeable energy storage systems alongside renewable energy; in particular, high-capacity battery packs are being used for electric vehicles to support driving and operating output.

[0004] Meanwhile, such high-capacity battery packs are composed of a combination of multiple battery cells, but for some reason, one cell may overheat and run wild, causing adverse effects on adjacent cells, so it is required that adjacent cells be thermally insulated from each other.

[0005] As for the performance requirements for such insulation materials, they must have low thermal conductivity to ensure excellent insulation performance, and in the case of high-temperature insulation materials, they must be able to withstand high temperatures. Furthermore, they must be moldable so that they can be applied to various industrial fields, and durability is also required to continuously maintain such insulation performance.

[0006] Aerogel is a material composed of silicon oxide (SiO2) with a specific surface area of ​​several hundred to 1,500 m² 2It is a transparent or translucent advanced nanostructure material with a porosity of over 90% and a thermal conductivity of approximately 90%. Aerogels with such a nanoporous structure have low thermal conductivity, so they not only have high potential as thermal insulators but are also evaluated as highly efficient ultra-insulating materials that can be used in various industrial fields.

[0007] However, aerogels, which are generally manufactured in the form of powder or particles, have very weak strength due to high brittleness, such as easily breaking even with a small impact, and are difficult to process into very thin thicknesses and shapes. Therefore, despite their excellent thermal insulation properties, there is a problem in that aerogels alone are very difficult to apply as thermal insulation materials.

[0008] In addition, mica is a silicate mineral found in large quantities in granite and is a crystal belonging to the monoclinic system. Although it has been widely used as an electrical insulator, it has a problem of poor durability, such as easily separating upon external impact, as it often takes the form of hexagonal plates and tends to split into thin pieces.

[0009] Accordingly, there was a need to develop insulation materials capable of securing thermal insulation and heat resistance while simultaneously improving durability.

[0010] The technical problem to be solved by the present invention is to provide an aerogel composition for a battery insulation sheet that includes heat-resistant fibers and an aerogel to secure thermal insulation and heat resistance while simultaneously improving durability, a battery insulation sheet using the same, and a method for manufacturing the same.

[0011] However, the problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0012] One embodiment of the present invention provides an aerogel composition for a battery insulation sheet comprising: a heat-resistant fiber; an aerogel; and a binder; wherein, based on 100 weight% of the total composition, the heat-resistant fiber is included in an amount of 30 weight% or more and 60 weight% or less, the aerogel is included in an amount of 20 weight% or more and 50 weight% or less, and the binder is included in an amount of 10 weight% or more and 20 weight% or less.

[0013] According to one embodiment of the present invention, the heat-resistant fiber is selected from the group consisting of carbon fiber, carbon fiber precursor, aramid fiber, ceramic fiber, basalt fiber, polymer fiber, and the same, and the heat-resistant fiber may not include glass fiber.

[0014] According to one embodiment of the present invention, the binder may include a water-based polymer binder.

[0015] According to one embodiment of the present invention, it may further include a flame retardant and a pigment.

[0016] According to one embodiment of the present invention, the flame retardant may be 2% by weight or more and 8% by weight or less with respect to 100% by weight of the total composition, and the pigment may be 1% by weight or more and 3% by weight or less with respect to 100% by weight of the total composition.

[0017] One embodiment of the present invention provides a battery insulation sheet comprising: a porous substrate including heat-resistant fibers and an aerogel; and a coating layer provided on at least one surface of the porous substrate and including a binder, wherein the heat-resistant fibers are in an amount of 30 parts by weight or more and 80 parts by weight or less and the aerogel is in an amount of 20 parts by weight or more and 70 parts by weight or less, with respect to 100 parts by weight of the porous substrate.

[0018] According to one embodiment of the present invention, the heat-resistant fiber is selected from the group consisting of carbon fiber, carbon fiber precursor, aramid fiber, ceramic fiber, basalt fiber, polymer fiber, and the same, and the heat-resistant fiber may not include glass fiber.

[0019] According to one embodiment of the present invention, the binder may include a water-based polymer binder.

[0020] According to one embodiment of the present invention, the coating layer may further comprise a flame retardant and a pigment, and the coating layer may not comprise an inorganic sealing layer.

[0021] One embodiment of the present invention provides a method for manufacturing a battery insulation sheet, comprising the steps of: manufacturing a porous substrate comprising a heat-resistant fiber and an aerogel; and forming a coating layer by applying a coating liquid composition comprising a binder onto the porous substrate.

[0022] An aerogel composition for a battery insulation sheet according to one embodiment of the present invention comprises a heat-resistant fiber; an aerogel; and a binder, which can secure thermal insulation and heat resistance while simultaneously improving durability.

[0023] A battery insulation sheet according to one embodiment of the present invention can improve flexibility and coating properties by using a substrate containing heat-resistant fibers.

[0024] A battery insulation sheet according to one embodiment of the present invention can improve flexibility and flame retardancy by having a coating layer containing a binder.

[0025] A method for manufacturing a battery insulation sheet according to one embodiment of the present invention can improve the flexibility and coating properties of the insulation sheet by using heat-resistant fibers and improve flame retardancy by forming a coating layer containing a binder.

[0026] FIG. 1 is a schematic diagram showing a battery insulation sheet structure according to one embodiment of the present invention.

[0027] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0028] In this specification, "A and / or B" means "A and B, or A or B".

[0029] In this specification, "about," "approximately," and "substantially" are used to mean a range of numerical values ​​or degrees or approximations thereof, taking into account inherent manufacturing and material tolerances, and are used to prevent an infringer from unfairly exploiting the disclosure in which precise or absolute figures provided to aid in understanding the invention are mentioned.

[0030] In this specification, when a component is described as being "on" one component, this means that, unless specifically stated otherwise, other components may be placed in between, without excluding the placement of other components.

[0031] In this specification, the characteristic of having pores means that a gaseous and / or liquid fluid can pass from one side to the other side of the object through a structure in which the object includes a plurality of pores and said pores are interconnected.

[0032] Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. The drawings may be exaggerated, omitted, or schematically illustrated to explain or emphasize the contents of an embodiment of the present invention.

[0033] FIG. 1 is a schematic diagram showing a battery insulation sheet structure according to one embodiment of the present invention.

[0034] The present invention will be described in more detail below.

[0035] One embodiment of the present invention comprises an aerogel composition for a battery insulation sheet, comprising a heat-resistant fiber; an aerogel; and a binder; wherein, based on 100 weight% of the total composition, the heat-resistant fiber is included in an amount of 30 weight% or more and 60 weight% or less, the aerogel is included in an amount of 20 weight% or more and 50 weight% or less, and the binder is included in an amount of 10 weight% or more and 20 weight% or less.

[0036] An aerogel composition for a battery insulation sheet according to one embodiment of the present invention comprises a heat-resistant fiber; an aerogel; and a binder, which can secure thermal insulation and heat resistance while simultaneously improving durability.

[0037] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet comprises heat-resistant fibers. As described above, by including heat-resistant fibers, the aerogel composition for a battery insulation sheet can serve as a structural support for the insulation sheet and can improve durability by increasing flexibility.

[0038] According to one embodiment of the present invention, the heat-resistant fiber is selected from the group consisting of carbon fiber, carbon fiber precursor, aramid fiber, ceramic fiber, basalt fiber, polymer fiber, and the same, and the heat-resistant fiber may not include glass fiber. Specifically, the heat-resistant fiber may be an organic fiber. As described above, by selecting an organic fiber as the heat-resistant fiber, the lightweighting and flexibility of the insulation sheet to be manufactured can be secured and durability improved compared to using inorganic fibers.

[0039] According to one embodiment of the present invention, the heat-resistant fiber may be a carbon fiber precursor. The carbon fiber precursor may refer to a fiber in a stage prior to being processed into a carbon fiber.

[0040] According to one embodiment of the present invention, the carbon fiber precursor may be one selected from the group consisting of PAN fiber (Polyacrylonitrile fiber), polyimide fiber (PI fiber), PBO fiber (Poly(p-phenylene benzobisoxazole)), and the same. Preferably, the carbon fiber precursor may be PAN fiber (Polyacrylonitrile fiber). Specifically, PAN fiber may refer to pre-oxidized fiber filaments used in the step prior to processing into carbon fiber, and the pre-oxidization process may refer to the process of oxidizing PAN (Polyacrylonitrile) fiber by heating it in air to a temperature of about 200°C to 300°C when manufacturing carbon fiber. In this process, the chemical structure of the PAN fiber changes, increasing heat resistance and providing stability during the carbonization process.

[0041] According to one embodiment of the present invention, the heat-resistant fiber may not include glass fiber. When using conventional glass fiber, glass can be melted and processed into a fine fiber form, and there were advantages such as high strength and excellent insulation properties. On the other hand, glass fiber has a higher density compared to organic fiber, which may increase the weight of the insulation sheet to be manufactured; it may be vulnerable to external impact due to low flexibility; and processability may be reduced. Accordingly, by selecting a heat-resistant fiber to replace the glass fiber, the insulation sheet to be manufactured can be made lighter and more flexible, and its durability can be improved.

[0042] A battery insulation sheet according to one embodiment of the present invention does not contain glass fibers, thereby preventing the brittleness and interfacial delamination problems characteristic of glass fibers and effectively suppressing cracking and separation phenomena caused by external impact or high-temperature environments.

[0043] In conventional technology regarding fire-retardant paints for protecting the surface of aerogel blankets, there have been attempts to improve fire-retardant performance and suppress crack formation upon bending by adding glass beads to the paint. Here, the glass beads are in the form of spherical inorganic particles that act as fillers or stress relievers within the paint to support the mechanical stability of the coating film.

[0044] However, glass beads are merely particulate inorganic materials dispersed within the paint composition and do not serve to form the framework of an insulating structure containing aerogel or to ensure structural stability. Furthermore, paints containing glass beads function only as an outer layer applied to the surface of an aerogel blanket and have limitations in fundamentally resolving issues such as aerogel brittleness or delamination.

[0045] According to one embodiment of the present invention, the heat-resistant fiber is 30% by weight or more and 60% by weight or less with respect to 100% by weight of the total composition. Specifically, the heat-resistant fiber may be 30% by weight or more and 55% by weight or less, 30% by weight or more and 50% by weight or less, 30% by weight or more and 45% by weight or less, 30% by weight or more and 40% by weight or less, 30% by weight or more and 38% by weight or less, 30% by weight or more and 36% by weight or less, 30% by weight or more and 34% by weight or less, 30% by weight or more and 32% by weight or less, or 30% by weight or less, with respect to 100% by weight of the total composition. If the above-described range is exceeded, the thermal conductivity may increase as the content of the aerogel decreases relatively, thereby degrading the thermal insulation performance; if the above-described range is not met, the structural support role may be degraded, thereby degrading mechanical strength, and flexibility may be degraded, thereby degrading durability.

[0046] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet comprises an aerogel. Generally, aerogel is a transparent or translucent advanced material with a nanoporous structure, and because it has very low density and low thermal conductivity, it is evaluated as a highly efficient ultra-insulating material that can be used in various industrial fields, as well as having high potential as an insulating material.

[0047] In addition, the biggest advantage of aerogel is that it has a lower thermal conductivity than conventional organic insulation materials such as styrofoam, and it can solve the problems of fire vulnerability and the generation of harmful gases in case of fire, which are fatal weaknesses of organic insulation materials.

[0048] However, generally, due to high brittleness, aerogels have very weak strength, easily breaking even with minor impacts, and are difficult to process into very thin thicknesses and shapes. Therefore, despite their excellent thermal insulation properties, there was a problem in that it was very difficult to manufacture insulation materials using aerogel alone.

[0049] Accordingly, the aerogel composition for a battery insulation sheet according to one embodiment of the present invention further includes heat-resistant fibers and a binder in addition to the aerogel to improve durability and minimize the generation of aerogel dust.

[0050] According to one embodiment of the present invention, the aerogel is 20% by weight or more and 50% by weight or less with respect to 100% by weight of the total composition. Specifically, the aerogel may be 25% by weight or more and 50% by weight or less, 30% by weight or more and 50% by weight or less, 35% by weight or more and 50% by weight or less, 40% by weight or more and 50% by weight or less, 42% by weight or more and 50% by weight or less, 44% by weight or more and 50% by weight or less, 46% by weight or more and 50% by weight or less, 48% by weight or more and 50% by weight or less, or 50% by weight or less, with respect to 100% by weight of the total composition. If the above-described range is exceeded, the content of heat-resistant fibers becomes relatively low, which may impair the structural support role of the insulation sheet, and due to the high brittleness of the aerogel, it may easily break even with a small impact. On the other hand, if the above-described range is not met, the overall thermal insulation performance may be reduced.

[0051] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet comprises a binder. As described above, by including a binder in the aerogel composition for a battery insulation sheet, dust characteristics can be improved when an insulation sheet is manufactured using the aerogel composition for a battery insulation sheet comprising the binder.

[0052] According to one embodiment of the present invention, the binder may comprise a water-based polymer binder. Specifically, the water-based polymer binder may comprise one or more selected from the group consisting of aqueous polymers, anionic water-soluble polymers, cationic water-soluble polymers, and water-dispersible polymers.

[0053] The above aqueous polymer may include, for example, one or more selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyacrylamide, and polyvinylpyrilidone, but is not limited thereto.

[0054] The above-mentioned anionic water-soluble polymer may include one or more selected from the group consisting of polymers having functional groups of carboxylic acids, sulfonic acids, sulfate esters, phosphate esters, and salts thereof. For example, the above-mentioned anionic water-soluble polymer may be a polymer having carboxylic acid groups, and may include, but is not limited to, polymaleic acid as a specific example.

[0055] The above-mentioned 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 above-mentioned cationic water-soluble polymer may be a polymer having amine groups, and as specific examples, may include one or more selected from the group consisting of polyethylene amine and polyamine, but is not limited thereto.

[0056] The above water-dispersible polymer may include one or more selected from the group consisting of water-dispersible polyurethane and water-dispersible polyester, and preferably, the water-dispersible polymer may be water-dispersible polyurethane. As described above, by selecting water-dispersible polyurethane as the water-dispersible polymer, the durability of the insulation sheet can be improved when manufacturing an insulation sheet including it, and it can perform the role of protecting from moisture by preventing moisture absorption, and it can be resistant to bending or folding of the insulation sheet due to its good elasticity and flexibility.

[0057] According to one embodiment of the present invention, the binder is included in an amount of 10% by weight or more and 20% by weight or less with respect to 100% by weight of the total composition. Specifically, the binder may be in an amount of 10% by weight or more and 19% by weight or less, 10% by weight or more and 18% by weight or less, 10% by weight or more and 17% by weight or less, 10% by weight or more and 16% by weight or less, 10% by weight or more and 15% by weight or less, 10% by weight or more and 14% by weight or less, 11% by weight or more and 14% by weight or less, 12% by weight or more and 14% by weight or less, or 13% by weight or less, with respect to 100% by weight of the total composition. By controlling the content of the binder within the above-described range, dust characteristics can be improved when manufacturing an insulation sheet using an aerogel composition for a battery insulation sheet containing the binder.

[0058] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet may comprise, based on 100 weight% of the total composition, 30 weight% or more and 50 weight% or less of the heat-resistant fiber, 30 weight% or more and 50 weight% or less of the aerogel, and 10 weight% or more and 15 weight% or less of the binder. When the aerogel composition for a battery insulation sheet is configured within the above range, excellent thermal insulation properties can be achieved while simultaneously improving durability.

[0059] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet may comprise, based on 100 weight% of the total composition, 30 weight% or more and 36 weight% or less of the heat-resistant fiber, 44 weight% or more and 50 weight% or less of the aerogel, and 10 weight% or more and 15 weight% or less of the binder. When the aerogel composition for a battery insulation sheet is configured within the above range, excellent thermal insulation can be achieved by improving the network between the heat-resistant fiber and the aerogel, and durability can be improved at the same time, and dust generation can be prevented by further including the binder.

[0060] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet may comprise, based on 100 weight% of the total composition, 30 weight% or more and 32 weight% or less of the heat-resistant fiber, 48 weight% or more and 50 weight% or less of the aerogel, and 10 weight% or more and 15 weight% or less of the binder. When the aerogel composition for a battery insulation sheet is configured within the above range, excellent thermal insulation can be achieved by improving the network between the heat-resistant fiber and the aerogel, and durability can be improved at the same time, and dust generation can be prevented by further including the binder.

[0061] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet may comprise 30% by weight of the heat-resistant fiber, 50% by weight of the aerogel, and 13% by weight of the binder, based on 100% by weight of the total composition. When the aerogel composition for a battery insulation sheet is configured within the above range, the network between the heat-resistant fiber and the aerogel is enhanced to achieve excellent thermal insulation and simultaneously improve durability, and dust generation can be prevented by further including the binder.

[0062] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet may optionally further include additives such as a wetting agent, an emulsifier, a compatibilizer, a viscosity modifier, a pH modifier, a stabilizer, an antioxidant, an acidic or basic capture agent, a metal inert, an antifoaming agent, an antistatic agent, a thickener, an adhesion improver, a binder, a flame retardant, an impact modifier, a pigment, a dye, a coloring agent, and a deodorizer.

[0063] According to one embodiment of the present invention, the aerogel composition for a battery insulation sheet may further include a flame retardant and a pigment. As described above, by further including a flame retardant and a pigment, the aerogel composition for a battery insulation sheet can improve high-temperature durability and structural stability, and also improve weather resistance and design elements.

[0064] According to one embodiment of the present invention, the flame retardant may be used alone or in combination from a group of nitrogen-based flame retardants including ammonium phosphate, ammonium carbonate, triazine compounds, melamine cyanurate, and guanidine compounds; a group of metal hydroxides including magnesium hydroxide and aluminum hydroxide; or a group of phosphorus-based flame retardants including melamine polyphosphate, ammonium polyphosphate, diammonium phosphate, monoammonium phosphate, polyphosphate amide, phosphate amide, melamine phosphate, and red phosphate. Preferably, the flame retardant may be a nitrogen-based flame retardant. More preferably, the flame retardant may be a triazine derivative flame retardant. Specifically, the triazine derivative flame retardant may be a triazine derivative-based non-halogen flame retardant and may have excellent high-temperature stability, UV resistance, and long-term durability.

[0065] According to one embodiment of the present invention, the flame retardant may be in an amount of 2% by weight or more and 8% by weight or less with respect to 100% by weight of the total composition. Specifically, the flame retardant may be in an amount of 2% by weight or more and 7% by weight or less, 2% by weight or more and 6% by weight or less, 3% by weight or more and 6% by weight or less, 4% by weight or more and 6% by weight or less, or 5% by weight with respect to 100% by weight of the total composition. By satisfying the flame retardant content within the above-described range, high-temperature durability and structural stability within the thermal insulation sheet can be improved.

[0066] According to one embodiment of the present invention, the color filler may include a conductive filler. Specifically, the conductive filler may be one or more selected from the group consisting of carbon-based fillers, metal-based fillers, metal-coated fillers, and the same.

[0067] According to one embodiment of the present invention, the carbon-based filler may be one or more selected from the group consisting of carbon black, carbon nanotubes (CNT), graphite, graphene, and the like, and preferably, the carbon-based filler may be carbon black. By selecting the carbon-based filler within the above-described range, electrical or thermal conductivity properties can be imparted during the manufacture of an insulating sheet, thereby dispersing heat and protecting the substrate beneath the coating.

[0068] According to one embodiment of the present invention, the pigment may be carbon black. As described above, by selecting carbon black as the pigment, excellent coloring power can be provided, excellent weather resistance and durability can be imparted, and conductive properties can be provided by having excellent electrical and thermal conductivity.

[0069] According to one embodiment of the present invention, the pigment may be in an amount of 1% or more and 3% or less with respect to 100% by weight of the total composition. Preferably, the pigment may be in an amount of 2% by weight with respect to 100% by weight of the total composition. By satisfying the content of the pigment within the above-described range, weather resistance and design elements within the thermal insulation sheet can also be improved.

[0070] One embodiment of the present invention comprises a battery insulation sheet (100) comprising: a porous substrate (110) comprising heat-resistant fibers and an aerogel; and a coating layer (130) provided on at least one surface of the porous substrate (110) and comprising a binder, wherein the heat-resistant fibers are 30 parts by weight or more and 80 parts by weight or less, and the aerogel is 20 parts by weight or more and 70 parts by weight or less, with respect to 100 parts by weight of the porous substrate (110). The heat-resistant fibers, aerogel, and binder are as described above.

[0071] A battery insulation sheet (100) according to one embodiment of the present invention can improve the flexibility of the insulation sheet and adhesion to the coating layer (130) by using a substrate comprising heat-resistant fibers and aerogel. Accordingly, the insulation sheet can maintain a stable shape even in an environment where bending or thermal deformation occurs.

[0072] In addition, the battery insulation sheet (100) according to one embodiment of the present invention does not contain glass fibers, thereby preventing the brittleness and interfacial delamination problems characteristic of glass fibers and effectively suppressing cracking and separation phenomena in the event of external impact or high-temperature environments.

[0073] A battery insulation sheet according to one embodiment of the present invention is based on a porous substrate containing heat-resistant fibers, and takes the form in which an aerogel is structurally bonded within the substrate. That is, the present invention can simultaneously secure thermal insulation performance and structural stability by forming a structure that supports the aerogel using flexible heat-resistant fibers as a framework, rather than adding particulate inorganic fillers such as glass beads to the paint.

[0074] Furthermore, the present invention does not include glass fibers and instead uses heat-resistant fibers with excellent flexibility, thereby effectively suppressing the problems of brittleness and interfacial delamination that were problematic in conventional glass-based inorganic materials.

[0075] A battery insulation sheet (100) according to one embodiment of the present invention can improve flexibility and flame retardancy and suppress dust generation by providing a coating layer (130) containing a binder. Accordingly, stable insulation performance can be maintained even in a battery pack environment involving high temperature or vibration.

[0076] Conventionally, a mica sheet was included on an aerogel sheet to secure basic electrical insulation and shock absorption functions, while simultaneously enhancing flame retardancy and thermal insulation and suppressing dust generation.

[0077] However, as both aerogel and mica are inorganic materials, they have low interfacial adhesion, which caused delamination between layers when heat or external impact was applied, resulting in limitations in long-term durability.

[0078] Furthermore, when conventional glass fibers were used as a substrate, there was a problem where the coating agent did not adhere sufficiently to the substrate surface due to the low surface energy of the glass fibers, and durability was reduced under bending or repetitive mechanical deformation conditions due to low flexibility. Consequently, there were limitations in stably applying the coating process.

[0079] Accordingly, the present invention introduces a flexible, heat-resistant fiber capable of replacing glass fiber as a substrate. The heat-resistant fiber has superior coating properties compared to glass fiber, allowing for the stable application of a coating process including a binder and improving adhesion between the substrate and the coating layer.

[0080] In addition, as the surface of the aerogel substrate is stably sealed by the introduction of the above coating process, there is no need to apply a separate mica sheet as in the past, thereby fundamentally resolving the problem of interlayer separation.

[0081] Accordingly, the thermal insulation sheet of the present invention can simultaneously achieve dust generation suppression, flame penetration prevention, and improved durability through the adhesion effect of the coating layer itself, even without including a separate inorganic sealing layer or mica sheet.

[0082] According to one embodiment of the present invention, the coating layer (130) may further include a flame retardant and a pigment. The flame retardant and the pigment are as described above.

[0083] According to one embodiment of the present invention, the coating layer (130) may not include an inorganic sealing layer. Although the battery insulation sheet according to one embodiment of the present invention does not include an inorganic sealing layer on the substrate, it can effectively suppress flame penetration and heat diffusion through the sealing effect of the coating layer itself. Accordingly, problems of peeling and reduced durability that may occur when applying an inorganic sealing layer, such as a mica sheet, can be fundamentally resolved.

[0084] A battery insulation sheet (100) according to one embodiment of the present invention may exhibit a very low thermal conductivity due to a porous substrate structure including an aerogel. Specifically, the thermal conductivity (W / m갋K) of the battery insulation sheet may be 0.01 or higher and 0.03 or lower. Specifically, the thermal conductivity (W / m갋K) of the battery insulation sheet may be 0.01 or higher and 0.025 or lower, 0.01 or higher and 0.023 or lower, 0.01 or higher and 0.022 or lower, 0.01 or higher and 0.021 or lower, 0.01 or higher and 0.020 or lower, or 0.015 or higher and 0.020 or lower. Here, thermal conductivity is a physical property indicating the degree to which a material transmits heat, and refers to the amount of heat transmitted per unit time when a temperature difference of 1 K is formed at both ends of a material with a thickness of 1 m. A lower thermal conductivity value indicates superior insulation performance.

[0085] The battery insulation sheet of the present invention forms a porous structure in which a substrate containing heat-resistant fibers and an aerogel are integrated, thereby suppressing the collapse of the pore structure even in high-temperature environments and effectively blocking heat transfer pathways. Accordingly, such a low thermal conductivity range can be reliably secured, and it provides a highly advantageous effect in delaying heat diffusion in the event of high-temperature events such as battery thermal runaway.

[0086] In particular, the battery insulation sheet of the present invention can maintain excellent thermal insulation performance due to the close adhesion structure between the coating layer and the substrate, even though it does not include a separate inorganic sealing layer, and is advantageous in terms of weight reduction and structural simplification.

[0087] According to one embodiment of the present invention, the density (kg / m²) of the battery insulation sheet (100) 3 ) may be between 100 and 300. Specifically, the density (kg / m³) of the battery insulation sheet is 3The density may be 110 or more and 300 or less, 125 or more and 300 or less, 160 or more and 300 or less, 180 or more and 300 or less, 190 or more and 300 or less, 210 or more and 300 or less, 220 or more and 300 or less, 160 or more and 250 or less, or 180 or more and 250 or less. By satisfying the density range of the battery insulation sheet within the above-described range, structural strength and durability can be improved, and thermal insulation performance can be improved. Specifically, since flame-retardant fibers form the framework of the porous substrate and play a role in maintaining the pore structure, if the fiber content decreases, the structural support of the substrate decreases, and pore shrinkage may occur during the drying process. Meanwhile, since aerogel is distributed in a form that fills the empty spaces between the fibers, the volume ratio of solids in the substrate increases as the aerogel content increases. As a result, when the aerogel content increases and the flame-retardant fiber content decreases, the apparent density of the insulation sheet may tend to increase.

[0088] According to one embodiment of the present invention, the flame retardancy of the battery insulation sheet (100) is a property that prevents or suppresses self-combustion when a fire source is removed, and may mean, for example, a grade of V-0 or higher in the UL94 V Test.

[0089] According to one embodiment of the present invention, the insulating properties of the battery insulation sheet (100) may mean properties that make it difficult to transmit electricity, and may be characterized, for example, by a Comparative Tracking Index (CTI) of 600 V or more.

[0090] One embodiment of the present invention comprises a method for manufacturing a battery insulation sheet (100), comprising the steps of: manufacturing a porous substrate (110) comprising heat-resistant fibers and an aerogel; and applying a coating liquid composition comprising a binder onto the porous substrate (110) to form a coating layer (130).

[0091] A method for manufacturing a battery insulation sheet according to one embodiment of the present invention can improve the flexibility and coating properties of the insulation sheet by using heat-resistant fibers and improve flame retardancy and suppress dust generation by forming a coating layer containing a binder.

[0092] A method for manufacturing a battery insulation sheet according to one embodiment of the present invention includes the step of manufacturing a porous substrate comprising heat-resistant fibers and an aerogel, and specifically, may include the step of preparing PAN fibers and a silica precursor.

[0093] According to one embodiment of the present invention, a silica sol can be prepared by mixing the silica precursor with an aqueous alcohol solution and using a Sol-Gel process.

[0094] According to one embodiment of the present invention, the prepared silica sol can be impregnated into a PAN fiber fabric and a gelation reaction can be carried out.

[0095] According to one embodiment of the present invention, a wet gel may be applied thereafter to perform surface modification and hydrophobic treatment, and a porous substrate may be manufactured through a supercritical drying process. Specifically, the supercritical drying process may be carried out by maintaining a temperature of 260°C to 350°C and a pressure of 80 bar to 150 bar for 0.2 to 3 hours. More specifically, the supercritical drying process may be carried out by maintaining a temperature of 300°C and a pressure of 100 bar for 1.5 hours.

[0096] According to one embodiment of the present invention, the method for manufacturing a battery insulation sheet includes the step of forming a coating layer by applying a coating liquid composition containing a binder onto the porous substrate. Specifically, the step of forming the coating layer may involve applying a coating liquid composition containing a binder onto the porous substrate, drying it by touch for 7 minutes at a temperature of 120°C, and then air-drying to form the coating layer.

[0097] According to one embodiment of the present invention, the insulation sheet may be an insulation sheet for a battery. In particular, it may be applied as a heat diffusion prevention material between battery cells and used to prevent fire caused by external physical impact or heat.

[0098] Hereinafter, the present invention will be described in detail with reference to examples to specifically explain the invention. However, the embodiments according to the present invention may be modified in various different forms, and the scope of the present invention is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain the present invention to those with average knowledge in the art.

[0099]

[0100] <Example 1>

[0101] manufacturing of porous substrates

[0102] PAN fibers (pre-oxidized fiber filments) and silica precursors were prepared.

[0103] For the Sol-Gel process, a silica sol was prepared by mixing an aqueous alcohol solution and the silica precursor.

[0104] Afterwards, the above PAN fiber fabric was impregnated with the above silica sol solution, and after removing impurities, a gelation reaction was carried out by aging at room temperature for 24 hours.

[0105] Subsequently, a wet gel was applied to perform surface modification and hydrophobic treatment (for 3 days or more), and after the hydrophobic reaction was completed, an aerogel sheet (porous substrate) was prepared through a supercritical drying process (maintained at a temperature of 260°C to 350°C and a pressure of 80 bar to 150 bar for 0.2 to 3 hours).

[0106] Formation of a coating layer

[0107] Polyurethane (CAS No. 51852-81-4) was prepared as a binder, a triazine derivative (Flamestab NOR 116, BASF, CAS No. 191680-81-6) as a flame retardant, and a pigment (Carbon black, 1333-86-4).

[0108] A coating solution composition was prepared by mixing the above binder, flame retardant, and pigment with water.

[0109] The porous substrate manufactured above was cut to a width of 500 mm, then immersed in a solution tank containing the coating liquid composition and coated.

[0110] Subsequently, an insulating sheet with a coating layer was manufactured by tack-drying at a temperature of 120°C for 7 minutes and then air-drying.

[0111] At this time, for a total of 100% by weight of the thermal insulation sheet including a porous substrate and a coating layer, the composition was 60% by weight of heat-resistant fiber, 20% by weight of aerogel, 13% by weight of binder, 5% by weight of flame retardant, and 2% by weight of pigment.

[0112]

[0113] <Example 2>

[0114] In the above Example 1, an insulating sheet was manufactured in the same manner as in Example 1, except that for 100% by weight of the total insulating sheet comprising a porous substrate and a coating layer, the composition was 50% by weight of heat-resistant fiber and 30% by weight of aerogel.

[0115]

[0116] <Example 3>

[0117] In the above Example 1, an insulating sheet was manufactured in the same manner as in Example 1, except that for 100% by weight of the total insulating sheet comprising a porous substrate and a coating layer, the composition was 36% by weight of heat-resistant fiber and 44% by weight of aerogel.

[0118]

[0119] <Example 4>

[0120] In the above Example 1, an insulating sheet was manufactured in the same manner as in Example 1, except that for 100% by weight of the total insulating sheet comprising a porous substrate and a coating layer, the composition was 32% by weight of heat-resistant fiber and 48% by weight of aerogel.

[0121]

[0122] <Example 5>

[0123] In the above Example 1, an insulating sheet was manufactured in the same manner as in Example 1, except that for 100% by weight of the total insulating sheet comprising a porous substrate and a coating layer, the composition was 30% by weight of heat-resistant fiber and 50% by weight of aerogel.

[0124]

[0125] <Comparative Example 1>

[0126] In the above Example 1, an insulating sheet was manufactured in the same manner as in Example 1, except that 80 weight% of the heat-resistant fibers and no aerogel were included for the entire insulating sheet comprising a porous substrate and a coating layer, with respect to 100 weight% of the total insulating sheet.

[0127]

[0128] <Comparative Example 2>

[0129] In the above Example 1, a thermal insulation sheet was manufactured in the same manner as in Example 1, except that glass fiber was used as the heat-resistant fiber and a coating layer containing a mica sheet was formed instead of a coating layer containing a binder.

[0130]

[0131] <Experimental Example>

[0132] Thermal conductivity measurement

[0133] The thermal conductivity of the insulation sheets manufactured in the above examples and comparative examples was measured using Thermtest’s HFM (Heat Flow Meter)-25 equipment, and the results are shown in Table 1 below.

[0134]

[0135] Flame retardant rating measurement

[0136] The flame retardancy of the insulation sheets manufactured in the above examples and comparative examples was evaluated in accordance with the UL 94 vertical combustion test standard. The specimen was placed and ignited with a burner for 10 seconds, then the burner was removed and the time until the fire on the specimen was extinguished was measured. After the combustion ended following the first flame contact, the specimen was ignited again for 10 seconds, and the combustion time and glowing time were measured. The combustion time and combustion pattern (whether the cotton ignited due to dripping, whether the fire reached the clamp) were determined, and the flame retardancy grade was measured and shown in Table 1 below.

[0137] V-0: Each individual test specimen in a set of five specimens arranged at 180° (vertically) along its longitudinal axis relative to the flame has a residual flame time of 10 seconds or less after the removal of the flame and does not generate any dripping plastic particles that ignite the cotton wool located beneath the test specimen. The total residual flame time for the set is a maximum of 50 seconds.

[0138] V-1: Unlike V-0, in this class, the maximum afterglow time for each individual test specimen in a set of 5 is 30 seconds, and ignition of drop particles or decongested cotton is not permitted in this class either. The total afterglow time for the set is a maximum of 250 seconds.

[0139] V-2: Unlike V-0 and V-1, in this grade, dripping plastic particles that ignite the cotton wool are formed. The afterglow time for each individual test specimen in the set of 5 is up to 30 seconds, and the total afterglow time for the set is up to 250 seconds.

[0140]

[0141] CTI measurement

[0142] The Comparative Tracking Index (CTI) is determined according to the international standard IEC 60112-2020 and can provide a quantitative measure of a composition's ability to function as an electrical insulating material under wet and / or contaminated conditions. To determine the CTI rating of a composition, two electrodes are placed on a molded test specimen. Subsequently, a voltage difference is generated between the electrodes while a 0.1% aqueous ammonium chloride solution is dropped onto the test specimen. The maximum voltage at which five specimens can withstand a test period without failure for 50 drops is determined. The test voltage ranges from 100 to 600 V and is increased in increments of 25 V. The voltage value at which failure occurs when 50 drops of electrolyte are dropped is the "Comparative Tracking Index." This value represents the relative track resistance of the material.

[0143]

[0144] Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Inclusion of Aerogel X OOOOO Aerogel Content (Weight%) 0 20 30 4 4 4 8 50 Flame Retardant Fiber Content (Weight%) 8 0 60 50 3 6 32 30 Density (kg / m²) 3 )80±30130±30155±30190±30210±30220±30 Thermal Conductivity (W / m·K) 0.030920.025250.022910.021130.020940.01990 Flame Retardant Grade UL94-V0UL94-V0UL94-V0UL94-V0UL94-V0UL94-V0CTI Test UnavailableCTI600CTI600CTI600CTI600CTI600

[0145]

[0146] According to Table 1 above, it can be seen that Comparative Example 1 has inferior thermal insulation performance compared to the Example because it does not contain aerogel in the aerogel composition for the battery insulation sheet, resulting in a higher thermal conductivity. Furthermore, in the case of the CTI test, Comparative Example 1 did not contain aerogel, making the test itself impossible due to solution permeability.

[0147] In the case of Examples 1 to 5, it can be seen that the aerogel composition for battery insulation sheets contains aerogel, and as the content increases, the thermal conductivity decreases, resulting in excellent insulation performance.

[0148]

[0149] Rear temperature measurement based on flame test

[0150] In this experiment, to evaluate the thermal insulation performance of the present invention, the thermal insulation sheets of Example 5 and Comparative Example 2 were used as test subjects.

[0151] To evaluate the thermal insulation performance under flame exposure, a test was conducted using a flame tester. Specifically, high-temperature conditions were applied by directly irradiating the front of the test specimen with a flame, and the maximum temperature on the rear (cool side) was measured using a temperature sensor located on the rear of the test specimen and is shown in Table 2 below.

[0152] (1) Test equipment: Flame tester

[0153] (2) Test conditions:

[0154] - Front flame temperature: Approx. 700°C to 800°C

[0155] - Flame Irradiation Time: Approx. 250 seconds

[0156] (3) Measurement item: Maximum temperature on cool side at the end of flame inspection

[0157]

[0158] Comparative Example 2 Example 5 Heat-resistant fiberglass fiber PAN fiber coating layer composition Mica binder Separate sealing treatment required / unnecessary Rear side Max temp.(°C) 378255 Penetration status Partially penetrating Non-penetrating

[0159]

[0160] According to Table 2 above, in the case of Comparative Example 2, the maximum rear temperature was measured at 378 ℃, and some flame penetration was observed. On the other hand, the insulation sheet of the present invention was measured at a maximum rear temperature of 255 ℃, and it was confirmed that it maintains stable insulation performance without flame penetration.

[0161] From the above experimental results, it can be confirmed that the thermal insulation sheet of the present invention provides excellent thermal insulation performance by exhibiting a significantly lower rear surface temperature compared to the comparative example under the same flame exposure conditions.

[0162] In particular, the present invention has the advantage of effectively suppressing flame penetration even in high-temperature environments by applying PAN fibers (pre-oxidized fiber filments) instead of glass fibers and exhibiting a flame-blocking effect without separate sealing treatment through a binder coating layer.

[0163] Accordingly, the insulation sheet of the present invention provides a highly advantageous effect for improving insulation and safety in high-temperature and fire-hazardous environments, such as battery packs.

[0164] Furthermore, the aerogel composition for a battery insulation sheet according to one embodiment of the present invention, the battery insulation sheet using the same, and the method for manufacturing the same include heat-resistant fibers and aerogel, thereby securing thermal insulation and heat resistance while simultaneously having flexibility to prevent delamination and improve durability.

[0165] [Explanation of the symbol]

[0166] 100: Battery insulation sheet

[0167] 110: Porous substrate

[0168] 130: Coating layer

Claims

1. Heat-resistant fiber; Aerogel; and Includes a binder; An aerogel composition for a battery insulation sheet, comprising, based on 100 weight% of the total composition, 30 weight% or more and 60 weight% or less of the heat-resistant fiber, 20 weight% or more and 50 weight% or less of the aerogel, and 10 weight% or more and 20 weight% or less of the binder.

2. In Claim 1, The above heat-resistant fiber is one selected from the group consisting of carbon fiber, carbon fiber precursor, aramid fiber, ceramic fiber, basalt fiber, polymer fiber, and the like. An aerogel composition for a battery insulation sheet, wherein the heat-resistant fibers above do not include glass fibers.

3. In Claim 1, The above binder comprises an aqueous polymer binder, an aerogel composition for a battery insulation sheet.

4. In Claim 1, Aerogel composition for battery insulation sheets, further comprising a flame retardant and a pigment.

5. In Claim 4, The flame retardant is 2% by weight or more and 8% by weight or less based on 100% by weight of the total composition, and An aerogel composition for a battery insulation sheet, wherein the pigment is 1% by weight or more and 3% by weight or less based on 100% by weight of the total composition.

6. A porous substrate comprising heat-resistant fibers and aerogel; and A coating layer comprising a binder, provided on at least one surface of the above-mentioned porous substrate; and A battery insulation sheet having, for every 100 parts by weight of the porous substrate, the heat-resistant fiber is 30 parts by weight or more and 80 parts by weight or less, and the aerogel is 20 parts by weight or more and 70 parts by weight or less.

7. In Claim 6, The above heat-resistant fiber is one selected from the group consisting of carbon fiber, carbon fiber precursor, aramid fiber, ceramic fiber, basalt fiber, polymer fiber, and the like. A battery insulation sheet in which the above heat-resistant fiber does not contain glass fiber.

8. In Claim 6, A battery insulation sheet in which the above binder comprises a water-based polymer binder.

9. In Claim 6, The above coating layer further includes a flame retardant and a pigment. A battery insulation sheet in which the above coating layer does not include an inorganic sealing layer.

10. A step of manufacturing a porous substrate comprising heat-resistant fibers and aerogel; and A method for manufacturing a battery insulation sheet, comprising the step of forming a coating layer by applying a coating liquid composition containing a binder onto the porous substrate.

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