Insulation member

Abstract

The present invention relates to an insulation member comprising a silica heat insulation composite and having an excellent elastic recovery rate after compression even after performing a compression process including a primary compression and a secondary compression, and to a battery module and a battery pack comprising same.

Description

Insulating member

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0178812 filed December 4, 2024 and U.S. Patent Application No. 19 / 401,592 filed November 26, 2025, and all contents disclosed in the documents of said patent applications are incorporated herein as part of this specification.

[0003] The present invention relates to an insulating member.

[0004] Silica insulation sheets containing a silica network structure in the fibers are widely used as functional insulation materials in construction or industrial sites, and recently, they are also being applied as insulation materials for batteries in electric vehicles.

[0005] Batteries used in electric vehicles and the like are high-output, high-capacity batteries that generate a significant amount of heat during the charging and discharging process. If this generated heat is not effectively removed, the risk of ignition or explosion increases due to heat accumulation. Therefore, to prevent thermal runaway, silica insulation sheets can be interposed between battery cells to provide a heat-blocking effect.

[0006] However, when silica insulation sheets are applied as insulation for batteries, battery cells undergo repeated expansion and contraction during the charging and discharging process. These periodic volume changes in the cells generate internal pressure and deformation, requiring the silica insulation sheets positioned between the cells to respond with compression and resilience. If the recovery elasticity of the silica insulation sheet after compression is insufficient, the sheet may be excessively compressed when the cell volume expands, potentially leading to structural collapse; conversely, when the cell volume contracts again, the sheet may fail to return to its original state, forming internal voids. This not only results in a degradation of insulation performance but can also negatively impact the efficiency and stability of the battery. In particular, this problem can become more severe as the battery undergoes repeated charging and discharging cycles.

[0007] One objective of the present invention is to provide a silica thermal insulation composite capable of effectively accommodating periodic volume changes of a cell occurring during the charging and discharging process of a battery, and a thermal insulation member comprising the same.

[0008] Another objective of the present invention is to provide a battery module and a battery pack comprising the above-described insulating member.

[0009] However, the technical 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.

[0010] According to one embodiment of the present invention, the invention relates to an insulating member comprising a silica insulating composite including a substrate and a silica network structure; and a film located on both sides of the silica insulating composite, wherein the insulating member has a thickness recovery rate after compression calculated according to Formula 1 below of 70% or more:

[0011] [Equation 1]

[0012]

[0013] In the above Equation 1, the thickness of the insulating member after the second compression is the thickness of the insulating member measured after first compressing the insulating member until the thickness after compression reaches 50±5% relative to the thickness before compression and maintaining it for 60 minutes, then secondly compressing the insulating member until the thickness reaches 40±5% relative to the thickness before compression and maintaining it for 60 minutes, and then maintaining the environment after removing the pressure for 6 minutes.

[0014] The above silica network structure includes a plurality of silica particles and may include one or more pores.

[0015] After repeating a compression process including first compression and second compression two or more times for the above-mentioned insulating member, the thickness recovery rate (%) of the insulating member may be 68% or more.

[0016] After repeating a compression process including first compression and second compression three times for the above-mentioned insulating member, the thickness recovery rate (%) of the insulating member may be 68% or more.

[0017] The thickness of the insulating member measured after the above two or more compression processes may be at least 0.90 times the thickness of the insulating member measured after one compression process.

[0018] The thickness of the above-mentioned insulating member may be 0.5 to 10 mm.

[0019] The above silica particles may include silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

[0020] The silica network structure within the above silica thermal insulation composite may include particles in which multiple silica particles with a particle size greater than 0 and less than or equal to 5 nm are aggregated or bonded.

[0021] The average particle size of the aggregated or combined particles may be 5 to 2,000 nm.

[0022] The density of the above silica thermal insulation composite is 0.05 to 0.50 g / cm³ 3 It could be.

[0023] The above silica network structure may include silica aerogel or be silica aerogel.

[0024] The above silica thermal insulation composite may be an aerogel composite comprising a substrate and a silica aerogel having a plurality of open pores.

[0025] The above silica insulation composite may be in the form of a sheet.

[0026] According to another embodiment of the present invention, the invention relates to a battery module comprising: one or more battery cells in an internal space; and the insulating member.

[0027] According to another embodiment of the present invention, the invention relates to a battery pack comprising a battery module including one or more battery cells in an internal space; and the insulating member.

[0028] The silica insulation composite according to the present invention has excellent resilience to compression. Therefore, when the above-described silica insulation composite is applied as an insulating material for batteries, structural stability and insulation performance can be maintained even under repeated volume changes caused by the expansion and contraction of cells during the charging and discharging process of the battery.

[0029] FIG. 1 is a perspective view of an insulating member according to one example.

[0030] FIG. 2a is a perspective view of an insulating member according to one example.

[0031] FIGS. 2b and 2c are cross-sectional views of an insulating member according to one example.

[0032] FIG. 3 is a front view of an insulating member according to one example.

[0033] FIG. 4 is a perspective view of an insulating member according to one example.

[0034] According to one embodiment of the present invention, a silica thermal insulation composite comprising a substrate and a plurality of silica particles and a silica network structure comprising one or more pores; and a thermal insulation member comprising a film located on both sides of the silica thermal insulation composite, wherein the thermal insulation member may have a thickness recovery rate after compression calculated according to Formula 1 below of 70% or more:

[0035] [Equation 1]

[0036]

[0037] In the above Equation 1, the thickness of the insulating member after the second compression is the thickness of the insulating member after the first compression until the thickness after compression reaches 50±5% relative to the thickness before compression, and then the thickness of the insulating member after the second compression until the thickness of the insulating member reaches 40±5% relative to the thickness before compression. More specifically, the thickness of the insulating member after the second compression is the thickness of the insulating member measured after maintaining the thickness for 60 minutes by performing the first compression until the thickness after compression reaches 50±5% relative to the thickness before compression, then performing the second compression until the thickness of the insulating member reaches 40±5% relative to the thickness before compression and maintaining the thickness for 60 minutes, and then maintaining the environment after removing the pressure for 6 minutes.

[0038] After repeating a compression process including first compression and second compression two or more times for the above-mentioned insulating member, the thickness recovery rate (%) of the insulating member may be 68% or more.

[0039] After repeating a compression process including first compression and second compression three times for the above-mentioned insulating member, the thickness recovery rate (%) of the insulating member may be 68% or more.

[0040] The thickness of the insulating member measured after the above two or more compression processes may be at least 0.90 times the thickness of the insulating member measured after one compression process.

[0041] The thickness of the above-mentioned insulating member may be 0.5 to 10 mm.

[0042] The above silica particles may include silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

[0043] The silica network structure within the above silica thermal insulation composite may include particles in which multiple silica particles with a particle size greater than 0 and less than or equal to 5 nm are aggregated or bonded.

[0044] The average particle size of the aggregated or combined particles may be 5 to 2,000 nm.

[0045] The density of the above silica thermal insulation composite is 0.05 to 0.50 g / cm³ 3 It could be.

[0046] According to another embodiment of the present invention, the invention relates to a battery module comprising one or more battery cells in an internal space; and the insulating member.

[0047] According to another embodiment of the present invention, the invention relates to a battery pack comprising the battery module described above.

[0048] Hereinafter, the present invention will be described in more detail to aid in understanding the invention. In this case, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0049]

[0050] According to one embodiment of the present invention, the invention relates to a thermal insulation member comprising a silica thermal insulation composite including a substrate and a silica network structure; and a film located on both sides of the silica thermal insulation composite.

[0051] The above silica network structure is a structure comprising a plurality of silica particles and one or more pores, and more specifically, refers to a network structure formed by connecting a plurality of silica particles in three dimensions. This structure forms a plurality of continuous pores between the silica particles, and these pores are connected to each other and distributed throughout the structure.

[0052] The silica particles may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof. Additionally, the silica particles may comprise primary particles having a size of approximately greater than 0 and less than 10 nm, or greater than 0 and less than 5 nm, preferably around 1 nm, and secondary particles formed by the aggregation of these particles. The secondary particles may have an average particle size of approximately 5 to 2,000 nm, 5 to 1,000 nm, 5 to 500 nm, 5 to 100 nm, or 5 to 50 nm, but are not limited thereto. The average particle size may be measured by any means known to those skilled in the art, such as scanning electron microscopy, dynamic light scattering, optical microscopy, or size exclusion methods, but is not limited thereto.

[0053] The pores included in the above silica network structure may include mesopores, or may include micropores or macropores. Here, the "mesopore" is a pore with an average pore diameter in the range of about 2 nm to about 50 nm, the "macropore" is a pore with an average pore diameter exceeding about 50 nm, and the "micropore" is a pore with an average pore diameter less than about 2 nm. The silica network structure may include at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% mesopores of the pore volume. The silica network structure may include mesopores. The silica network structure may include mesopores and micropores. The above pore size can be measured by any means known to those skilled in the art, such as gas adsorption experiments, mercury infiltration, capillary flow porometry, or positron annihilation lifetime spectroscopy (PALS), but is not limited thereto.

[0054] The above silica network structure is not particularly limited as long as it includes silica particles and has the above-described network structure, but may include aerogel.

[0055] The above "aerogel" comprises a plurality of primary aerogel particles having a size of approximately greater than 0 and less than 10 nm, greater than 0 and less than 5 nm, and secondary aerogel particles formed by the aggregation or bonding of these primary aerogel particles, and as a plurality of open pores are formed between the primary aerogel particles and between the secondary aerogel particles to form aggregates, the aerogel forms a three-dimensional network structure.

[0056] The above aerogel may be an inorganic silica aerogel formed from a silicon alkoxide-based compound or water glass as a precursor. The above aerogel may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof. The above aerogel may have at least some of the SiO2 on the surface of the SiO2 network structure having a bonding structure of Si-O-SiO2(CH3), Si-O-SiO(CH3)2, or Si-O-Si(CH3)3. The specific manufacturing process of the silica aerogel is described in detail below.

[0057] The above substrate may be a fiber substrate comprising a plurality of fibers. The silica thermal insulation composite has a structure in which at least some of a plurality of silica particles (or aerogel particles) are dispersed, preferably bonded, on the surface of the fibers within the substrate, and at the same time, at least some of a plurality of silica particles (or aerogel particles) are dispersed, preferably located, in the empty spaces between the dispersed fibers within the substrate.

[0058] The above "aerogel particles" are particles in the form of individual solid units constituting the aerogel, and may include primary aerogel particles having a size of approximately greater than 0 and less than 10 nm, or greater than 0 and less than 5 nm, preferably around 1 nm, and secondary aerogel particles formed by the aggregation of these particles. However, the aerogel within the silica insulation composite is mostly in the form of secondary aerogel particles or aggregated and bonded thereof, and a small amount of primary aerogel particles that do not form secondary aerogel particles may be mixed in. The above secondary aerogel particles may have an average particle size of approximately 5 to 2,000 nm, 5 to 1,000 nm, 5 to 500 nm, 5 to 100 nm, or 5 to 50 nm, but are not limited thereto. In the present invention, the average particle size may be measured by any means known to those skilled in the art, such as scanning electron microscopy, dynamic light scattering, optical microscopy, or size exclusion methods, but is not limited thereto.

[0059] The aerogel may have a matrix framework structure including mesopores, and may include micropores or macropores in addition to the mesopores. In the present invention, the aerogel may include at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% mesopores of the pore volume of the framework structure. The aerogel may include mesopores. The aerogel may include mesopores and micropores. The pore size may be measured by any means known to those skilled in the art, such as gas adsorption experiments, mercury infiltration, capillary flow porometry, or positron annihilation lifetime spectroscopy (PALS), but is not limited thereto.

[0060] Examples of the above-described materials may include discrete fibers, films, sheets, nets, fibers, porous materials, foams, nonwoven materials, or laminates of two or more layers thereof. Additionally, depending on the application, the surface may have a surface roughness or be patterned.

[0061] The above description refers to polyester, polyolefin terephthalate, poly(ethylene) naphthalate, polycarbonate, regenerated cellulose (e.g., rayon), cotton, polyamide (e.g., nylon), spandex (e.g., Lycra from DuPont), carbon (e.g., graphite), polyacrylonitrile (PAN), PAN oxide, non-carbonized heat-treated PAN (e.g., from SGL Carbon), glass fiber-based materials (S-glass, 901 glass, 902 glass, 475 glass, E-glass, etc.), silica-based fibers, e.g., quartz (e.g., Saint-Gobain Quartzel), Q-Fiber felt (from Johns Manville), Saffil, Durablanket (from Uniflex), or other silica fibers, Duraback (from carborundum), polyaramid fibers, e.g., Kevlar, Nomex, Sontera (all from DuPont), Conex (from Tyzine), polyolefins, e.g., Tyvek (Made by DuPont), Dyneema (Made by DSM), Spectra (Made by Honeywell), other polypropylene fibers, e.g., Typar, Xavan (both made by DuPont), fluoropolymers, e.g., PTFE under the trade name Teflon (Made by DuPont), Goretex (Made by WL GORE), silicon carbide fibers, e.g., Nicalcon (Made by COI Ceramics), ceramic paper, ceramic fibers, e.g., Nextel (Made by 3M), acrylic polymers, basalt fibers, wool, silk, hemp, leather, suede fibers, PBO-Xylon fibers (Made by Tyobo), liquid crystal materials, e.g., Vectan (Made by Hoechst), Cambrel fibers (Made by DuPont), polyurethane, wool fibers, boron, aluminum, iron, stainless steel fibers, or other thermoplastic resins such as PEEK, PES, PET, PEK, PPS, etc., but may be used without limitation as long as the fiber contains a silica three-dimensional structure or spaces or voids that facilitate the insertion of aerogel, thereby further improving thermal insulation performance. there is.The above description may include, but is not limited to, glass fibers, basalt fibers, ceramic fibers and / or ceramic paper.

[0062] The thickness of the above-mentioned substrate may be 0.5 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 2.5 mm or more, or 3 mm or more, and may be 20 mm or less, 15 mm or less, 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, 3.5 mm or less, or 3 mm or less. For example, the thickness of the above-mentioned substrate may be 0.5 to 20 mm, 0.5 to 10 mm, 0.5 to 5 mm, 0.5 to 4 mm, or 0.5 to 3.5 mm, but is not limited thereto.

[0063] The above silica insulation composite may have a rectangular shape in which a substrate and a silica network structure (e.g., aerogel) are mixed from the top surface to the bottom surface, but is not limited thereto.

[0064] In addition, at least a portion of the upper or lower surface of the silica insulation composite, preferably the entire surface, may have a flat shape. Here, the "flat shape" means that no irregularities are formed by intentional embossing or coating processes. In the present invention, forming the upper and lower surfaces of the silica insulation composite flat as described above can improve ease of operation when laminating support members, such as sheets, onto the upper and lower surfaces, and can increase the adhesion retention rate of the support members. Furthermore, it is desirable to reduce friction with adjacent equipment surfaces even when the silica insulation composite itself is applied directly as an insulation member without support members.

[0065] In addition, in the present invention, the thickness of the silica thermal insulation composite may be 0.5 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 2.5 mm or more, or 3 mm or more, and may be 20 mm or less, 15 mm or less, 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, 3.5 mm or less, or 3 mm or less. For example, the thickness of the silica thermal insulation composite may be 0.5 to 20 mm, 0.5 to 10 mm, 0.5 to 5 mm, 0.5 to 4 mm, or 0.5 to 3.5 mm, but is not limited thereto.

[0066] In the present invention, the density of the silica thermal insulation composite is 0.05 to 0.50 g / cm³ 3 , 0.05 to 0.35 g / cm² 3 , 0.05 to 0.30 g / cm² 3 , 0.10 to 0.35 g / cm² 3 , 0.10 to 0.30 g / cm² 3 , 0.15 to 0.35 g / cm² 3 1 or 0.15 to 0.30 g / cm² 3 It may be, but is not limited to this.

[0067] The above silica insulation composite may have a thermal conductivity of 30.0 mW / mK or less, 25.0 mW / mK or less, or 20.0 mW / mK or less at room temperature (23±2 ℃), and within this range, the thermal insulation performance of the silica insulation composite can be maximized.

[0068] The above silica insulation composite may have a high temperature (150 ℃) thermal conductivity of 35.0 mW / mK or less, 30.0 mW / mK or less, or 25.0 mW / mK or less, and within this range, the thermal insulation performance of the silica insulation composite can be maximized.

[0069] The above silica thermal insulation composite may have excellent mechanical strength, with a compressive strength at 10% deformation of 20 kPa to 80 kPa, 20 kPa to 70 kPa, 30 kPa to 80 kPa, 30 kPa to 70 kPa, 35 kPa to 80 kPa, or 35 kPa to 70 kPa. Here, the compressive strength may be measured by manufacturing a specimen according to ASTM C165.

[0070] The above silica thermal insulation composite has a tensile strength of 30 N / cm 2 up to 60 N / cm 2 , 40 N / cm 2 Up to 55 N / cm 2 , or 45 N / cm 2 Up to 55 N / cm 2 As such, it may have excellent flexibility. Here, the tensile strength may be measured by manufacturing a specimen according to ASTM D638 standards.

[0071] A film may be positioned on both sides of the above-described silica insulating composite. Additionally, a film may be positioned on the side surface in the thickness direction of the silica insulating composite. Therefore, the silica insulating composite may have a structure encapsulated by a film.

[0072] The above film may comprise polyethylene (PE) resin, polyethylene terephthalate (PET) resin, polypropylene (PP) resin, or a mixture thereof. The above film may be a PET film, but is not limited thereto.

[0073] The thickness of the above film is not particularly limited, but, for example, it may be 0.1 to 100 μm, 1 to 50 μm, 10 to 50 μm, or 25 to 40 μm.

[0074] In addition, an adhesive layer or an adhesive layer may be located on the opposite side of the silica thermal insulation composite among the two sides of the above film.

[0075] The above adhesive layer or adhesive layer may include, but is not limited to, an acrylic adhesive, a polyurethane adhesive, an olefin adhesive, an SBR rubber adhesive, or a silicone adhesive.

[0076] The thickness of the adhesive layer or the adhesive layer is not particularly limited and, for example, may be 0.1 to 100 μm, 1 to 50 μm, 10 to 50 μm, or 25 to 50 μm.

[0077] The above film may have a heat generation amount of 1,000 to 3,500 J / g, 1,100 to 3,000 J / g, 1,500 to 3,000 J / g, 2,000 to 3,000 J / g, or 2,500 to 3,000 J / g, but is not limited thereto.

[0078] In addition, the thickness of the insulation member may be 0.5 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 2.5 mm or more, or 3 mm or more, and may be 20 mm or less, 15 mm or less, 10 mm or less, 9 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, 3.5 mm or less, or 3 mm or less. For example, the thickness of the insulation member may be 0.5 to 20 mm, 0.5 to 10 mm, 0.5 to 5 mm, 0.5 to 4 mm, or 0.5 to 3.5 mm, but is not limited thereto.

[0079] FIG. 1 illustrates a perspective view of an insulating member according to one example, in which a film (200) cut into a shape corresponding to the upper and lower surfaces of a rectangular sheet-shaped silica insulating composite (100) is laminated. FIG. 2a illustrates a perspective view of an insulating member according to one example, and FIG. 2b and FIG. 2c illustrate a longitudinal cross-sectional view and a width cross-sectional view, respectively. The long cut film (200) is arranged to surround the upper surface, side, lower surface, and other side of the silica insulating composite (100; dotted line) in the width direction (A direction). Another cut film (200') is arranged to surround the upper surface, side, lower surface, and other side of the silica insulating composite in the length direction (B direction), which is orthogonal to the width direction (A direction). Accordingly, two layers of film (200, 200') are laminated on the upper and lower surfaces of the silica insulation composite, while a single layer of film (200 or 200') is laminated on the side of the silica insulation composite. At this time, the two ends of a single film may be joined together at the corners of the silica insulation composite (or at any arbitrary location). Although not shown in the drawings, a sealing portion may exist where the two ends overlap each other. FIG. 3 shows a front view of an insulation member according to another example, in which a silica insulation composite (100) is accommodated inside a folded film (200), and a sealing portion (S1) is formed by joining a film along the outer edge of the silica insulation composite. Although not shown in the drawings, a structure in which a silica insulation composite is interposed between two films and a sealing portion is formed by the two films being joined along the outer edge of the silica insulation composite is also included within the scope of the present invention.FIG. 4 illustrates a perspective view of an insulating member according to another example, wherein a silica insulating composite (100) is positioned inside a film (200), and then the film (200) is folded to surround all sides of the silica insulating composite (100) in accordance with the shape of the silica insulating composite (100), and the two ends of the film (200) overlap on one side of the silica insulating composite (100) to form a sealing portion (S2).

[0080] In lithium-ion batteries, as the volume of the cells expands and contracts during the charging and discharging process, the insulating material interposed between the cells is subjected to an environment of compression and relaxation. During battery charging, the insulating material is compressed due to the expansion of the cell volume, while during discharge, the pressure applied to the insulating material decreases due to the contraction of the cell volume. At this time, the insulating material must be able to elastically compress and recover in response to changes in cell volume to provide an effective insulation effect during battery operation. However, if the structural strength and elasticity of the insulating material are not both excellent, the structure may collapse during cell volume expansion. Alternatively, even if compression and recovery occur during the initial stages of the battery cycle, the volume capacity of the insulating material will eventually drop rapidly as cell volume changes occur repeatedly, leading to structural collapse.

[0081] As a result of diligent efforts, the inventors of the present invention have developed an insulating member comprising a silica insulating composite that possesses excellent elastic recovery properties against compression, and can maintain structural stability and thermal insulation performance even under repeated volume changes caused by the repeated expansion and contraction of the cell during the charging and discharging process of a battery.

[0082] When the insulating member according to the present invention is first compressed to a thickness of about 50% and secondly compressed to a thickness of about 40%, the thickness recovery rate of the insulating member may be 70% or more, 73% or more, 75% or more, 77% or more, 80% or more, 83% or more, 85% or more, 87% or more, 90% or more, 93% or more, or 95% or more.

[0083] The above secondary compression and primary compression simulate the environment of cell volume expansion due to charging and cell contraction due to discharging, respectively, during battery operation.

[0084] The above compression process can be performed by applying pressure in a horizontal direction (transverse direction) to the cross-section of the insulating member. That is, it means applying force (pressure) to the insulating member in the direction from the upper surface to the lower surface or from the lower surface to the upper surface, i.e., in the thickness direction. At this time, the specific pressure intensity is not specifically limited, and any intensity that can reduce the thickness of the insulating member to the above-mentioned range due to compression may be included without limitation. However, as a non-limiting example, pressure may be applied with an intensity of 0.5 to 10 kPa, 0.5 to 5 kPa, 1 to 5 kPa, 0.5 to 3 kPa, or 1 to 3 kPa.

[0085] The equipment used in the above compression process is not specifically limited, and any equipment capable of maintaining the compressed state of the insulating member for a predetermined period of time by applying force in the thickness direction of the insulating member may be used without restriction. The equipment may include a plate capable of fixing the specimen and a compression jig capable of applying pressure to the specimen in the thickness direction.

[0086] When the insulating member is compressed during the first compression above, and the thickness of the insulating member reaches about 50% (i.e., 50±5%) of the thickness after compression relative to the thickness before compression, such a compressed state can be maintained for 40 minutes or more, 50 minutes or more, 60 minutes or more, or 70 minutes or more, and 80 minutes or less. Preferably, the compressed state can be maintained for about 60 minutes.

[0087] After the first compression, the insulating member is subjected to a second compression with a pressure greater than that of the first compression. The second compression is performed immediately after the first compression and may not include a non-pressurized resting period between the first and second compressions. When the thickness of the insulating member reaches approximately 40% (i.e., 40±5%) of the thickness before compression (initial thickness before the first compression) during the second compression, such a compressed state can be maintained for 40 minutes or more, 50 minutes or more, 60 minutes or more, or 70 minutes or more, and 80 minutes or less. Preferably, the compressed state can be maintained for approximately 60 minutes.

[0088] After the above secondary compression, the thickness recovery rate (%) of the insulation member may be 70% or more, 73% or more, 75% or more, 77% or more, 80% or more, 83% or more, 85% or more, 87% or more, 90% or more, 93% or more, or 95% or more.

[0089] The above thickness recovery rate can be calculated according to the following Equation 1. That is, the thickness recovery rate is the percentage (%) of the thickness of the insulating member measured after removing the pressure applied to the insulating member after secondary compression, relative to the thickness of the insulating member before compression.

[0090] [Equation 1]

[0091]

[0092] In the above Equation 1, the unit of thickness of the insulating member for measuring the thickness recovery rate of the insulating member is not specifically limited and may be cm or mm, but preferably may be mm.

[0093] In addition, in Equation 1 above, "thickness of the insulating member after secondary compression" may be measured in a state where all pressure applied to the insulating member after secondary compression (after the secondary pressurization holding process) has been removed, i.e., in a non-compressed state. At this time, the thickness of the insulating member can be measured after maintaining the non-compressed state for 3 minutes or more, 4 minutes or more, 5 minutes or more, 6 minutes or more, or 7 minutes or more and 10 minutes or less. Preferably, the thickness of the insulating member can be measured after maintaining the non-compressed state for about 6 minutes.

[0094] The insulating member according to the present invention has excellent elastic recovery properties even with repeated changes in cell volume.

[0095] After repeating the compression process including the first compression and second compression of the insulation member two or more times, the thickness recovery rate (%) of the insulation member may be 68% or more, 70% or more, 73% or more, 75% or more, 77% or more, 80% or more, 83% or more, 85% or more, 87% or more, 90% or more, 93% or more, or 95% or more. At this time, the upper limit of the thickness recovery rate is not specifically limited, but preferably may be 100% or less, or 98% or less, 95% or less, or 93% or less.

[0096] The aforementioned compression process for the insulating member being repeated twice simulates an environment where the volume of the battery cell undergoes repeated expansion and contraction. This can be performed by continuing the first and second compressions without a rest period after the compression process consisting of first and second compressions for the insulating member. In this case, the compression process unit consisting of first and second compressions may be repeated two or more times, three or more times, four or more times, five or more times, six or more times, seven or more times, eight or more times, nine or more times, or ten or more times.

[0097] In addition, the thickness recovery rate of the insulating member after repeating the compression process, including the first compression and second compression of the insulating member, two or more times may be measured in a state where all pressure applied to the insulating member after the second compression of the last performed compression process has been removed (uncompressed state). At this time, the uncompressed state may be maintained for 3 minutes or more, 4 minutes or more, 5 minutes or more, 6 minutes or more, or 7 minutes or more and 10 minutes or less, and preferably for about 6 minutes.

[0098] After repeating the compression process including the first compression and second compression of the insulation member twice, the measured thickness recovery rate (%) of the insulation member may be 68% or more, 70% or more, 73% or more, 75% or more, 77% or more, 80% or more, 83% or more, 85% or more, 87% or more, 90% or more, or 93% or more, and may be 100% or less, 98% or less, or 95% or less.

[0099] After repeating the compression process including the first compression and second compression of the insulation member three times, the measured thickness recovery rate (%) of the insulation member may be 68% or more, 70% or more, 73% or more, 75% or more, 77% or more, 80% or more, 83% or more, 85% or more, 87% or more, or 90% or more, and may be 100% or less, 98% or less, or 95% or less.

[0100] In addition, the thickness of the insulating member measured after two or more compression processes with respect to the above insulating member may be 0.90 times or more, 0.91 times or more, 0.92 times or more, 0.93 times or more, 0.94 times or more, 0.95 times or more, 0.96 times or more, 0.97 times or more, 0.98 times or more, or 0.99 times or more than the thickness of the insulating member measured after one compression process. In this case, the upper limit is not specifically restricted, but may be 1 time or less.

[0101] The thickness of the insulating member measured after two compression processes for the above insulating member may be 0.90 times or more, 0.91 times or more, 0.92 times or more, 0.93 times or more, 0.94 times or more, 0.95 times or more, 0.96 times or more, 0.97 times or more, 0.98 times or more, or 0.99 times or more than the thickness of the insulating member measured after one compression process. In this case, the upper limit is not specifically restricted, but may be 1 time or less.

[0102] The thickness of the insulating member measured after three compression processes for the above insulating member may be 0.90 times or more, 0.91 times or more, 0.92 times or more, 0.93 times or more, 0.94 times or more, 0.95 times or more, 0.96 times or more, 0.97 times or more, 0.98 times or more, or 0.99 times or more than the thickness of the insulating member measured after one compression process. In this case, the upper limit is not specifically restricted, but may be 1 time or less.

[0103] The thickness recovery rate after the compression process of the above-mentioned insulating member may be measured by the following method, but is not limited thereto: a specimen of the insulating member is placed between compression jigs, and the initial thickness of the specimen is measured by adjusting the height of the compression jig to 5 to 10 mm / min, for example, at a speed of about 8 mm / min, so that a pressure of 1 to 5 kPa, for example, about 2 kPa is applied to the specimen. The specimen is compressed by adjusting the jig to a speed of 8 mm / min to achieve a thickness of 50% of the measured initial thickness, and then maintained for 60 minutes. Afterward, the specimen is compressed by adjusting the compression jig to a speed of 8 mm / min to achieve a thickness of 40% of the initial thickness, and then maintained for 60 minutes. Afterward, the compression jig is released at a speed of 8 mm / min so that the pressure applied to the specimen becomes 0, and then maintained for 6 minutes. When 6 minutes have elapsed, the height of the compression jig is adjusted at a speed of 8 mm / min so that a pressure of 2 kPa is applied to the specimen, and the final thickness of the specimen is measured. Even when measuring the thickness of an uncompressed specimen, deviations in the thickness measurement may occur due to natural volume changes or surface non-uniformity of the silica thermal insulation composite material. Therefore, when measuring the thickness of the specimen before or after (intentional) compression, the thickness can be measured by applying a low pressure to the specimen, for example, about 2 kPa. However, applying pressure to measure the thickness of an uncompressed specimen and the magnitude of the applied pressure are not limited to 2 kPa; any method that allows for the reproducible measurement of the specimen thickness may be included without limitation.

[0104] The size of the specimen of the insulating member used in the above experiment is not specifically limited, but, for example, a specimen with dimensions of 5 mm x 5 mm can be used.

[0105] The thickness recovery rate of the insulating member after compression may be obtained by randomly obtaining a total of five cuboidal specimens from the insulating member and calculating the average value of the thickness recovery rates measured for each specimen. In this case, the five specimens may be obtained by arbitrarily placing the center of the specimen at a position 10 cm away from each corner of the insulating member manufactured in a rectangular shape (e.g., a size of approximately 60 cm x 12 cm in width x height, but not limited thereto), and obtaining one specimen at a position 10 cm away from the center of the insulating member, but not limited thereto, and specimens obtained at any position may be used.

[0106] The insulating member with excellent recovery ability upon compression provided by the present invention can be applied as an insulating material for batteries, but it can also be applied as an insulating material, thermal insulation material, or non-combustible material in the construction, aviation, automotive, home appliance, semiconductor, or industrial equipment fields.

[0107] A method for manufacturing an insulating member according to the present invention may include the steps of: preparing a silica insulating composite; and surrounding the silica insulating composite with a film. The silica insulating composite may generally be formed by the steps of: preparing a silica sol; gelling after impregnating a substrate with the silica sol; and drying. Each step is described below. However, the specific manufacturing processes or examples described herein are not intended to limit any particular type of aerogel composite or its manufacturing method. This specification may include any silica insulating composite formed by any associated manufacturing method known to a person skilled in the art.

[0108] Silica sol preparation steps

[0109] In the present invention, a silica sol can be prepared using a silica precursor composition.

[0110] The above silica precursor composition includes a silica precursor, wherein the silica precursor can be used without limitation as long as it is a precursor that can be used to form, for example, an aerogel, with a silica three-dimensional network structure. For example, silicon-containing alkoxide compounds such as tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetrasecondary butyl orthosilicate, tetratertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl It may be a tetraalkyl silicate such as tetracyclohexyl orthosilicate, tetradodecyl orthosilicate, etc., and preferably may be tetraethyl orthosilicate (TEOS), but is not limited thereto.

[0111] In addition, the silica precursor may be a water glass solution. Here, the water glass solution may refer to a diluted solution obtained by adding distilled water to water glass and mixing it, and the water glass may be sodium silicate (Na2SiO3), which is an alkali silicate obtained by melting silicon dioxide (SiO2) and an alkali.

[0112] In addition, the silica precursor may include pre-hydrolyzed TEOS (HTEOS). HTEOS is an ethyl silicate oligomer material with a broad molecular weight distribution, and since it can control physical properties such as gelation time when synthesized from TEOS monomers in the form of an oligomer, it can be easily applied according to the user's reaction conditions. Furthermore, it has the advantage of producing reproducible physical properties of the final product. The HTEOS may generally be synthesized by a condensation reaction of TEOS that has undergone a partial hydration step under acidic conditions. That is, the HTEOS may be in the form of an oligomer prepared by condensing TEOS, and the oligomer may be partially hydrated.

[0113] The above-mentioned fully hydrolyzed silica precursor can be prepared by mixing a silica precursor and an organic solvent in a weight ratio of 1:0.1 to 1.5, 1:0.5 to 1.5, or 1:0.5 to 1.2, but is not limited thereto.

[0114] In addition, the above-mentioned fully hydrolyzed silica precursor can be prepared by mixing the silica precursor and water in a molar ratio of 1:0.1 to 10, 1:1 to 8, or 1:2 to 6, but is not limited thereto.

[0115] In the present invention, the silica precursor composition may further include a silicate containing a hydrophobic group. In the present invention, the silicate containing the hydrophobic group is not limited in type as long as it is an alkyl silane compound containing an alkyl group that induces hydrophobization and a silane functional group that can react with the -Si-O- functional group of the wet gel; however, specific examples include one or more selected from the group consisting of methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), methyltrimethoxysilane (MTMS), dimethyldiethoxysilane (DMDES), ethyltriethoxysilane (ETES), and phenyltriethoxysilane (PTES), but is not limited thereto. To increase the pore strength and elasticity of the gel, the silica precursor composition may include one or more silicates among trimethylethoxysilane (TMES) and dimethyldiethoxysilane (DMDES).

[0116] When the silica precursor composition includes a silicate containing the hydrophobic group, the silicate containing the hydrophobic group may be included in a molar ratio of 9:1 to 1:9 with the tetraalkyl silicate (molar ratio of silicate containing the hydrophobic group to tetraalkyl silicate). Within this range, the strength and thermal insulation performance of the silica thermal insulation composite can be improved.

[0117] In addition, the silica concentration of the silica precursor composition is 10 kg / m² 3 up to 100 kg / m² 3 , 20 kg / m 3 up to 80 kg / m² 3 , 30 kg / m 3 Up to 70 kg / m² 3 , 30 kg / m 3 up to 60 kg / m² 3 , or 35 kg / m² 3 Up to 45 kg / m 3It may be, but is not limited thereto. The above silica concentration is the concentration of silica contained in the silica precursor relative to the silica precursor composition, and can be appropriately adjusted by varying the content of the silica precursor, organic solvent, and water.

[0118] The above silica precursor may be used in an amount such that the silica content contained in the silica sol is 0.1% by weight to 30% by weight, but is not limited thereto. If the silica content satisfies the above range, both the mechanical properties and the thermal insulation properties of the silica thermal insulation composite can be improved.

[0119] The above silica sol may include water and / or a polar organic solvent in the silica precursor composition.

[0120] When preparing the above silica sol, the silica precursor composition and water may be mixed in a molar ratio of 1:1 to 10, 1:2 to 10, or 1:5 to 10, but are not limited thereto.

[0121] The above polar organic solvent may include alcohols, specifically examples of which include monohydric alcohols such as methanol, ethanol, isopropanol, butanol, etc.; polyhydric alcohols such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol, etc.; or combinations thereof, but other solvents known to those skilled in the art may also be used without limitation. Among these, the polar organic solvent may be a monohydric alcohol having 1 to 6 carbon atoms, such as methanol, ethanol, isopropanol, butanol, etc., such as ethanol, when considering miscibility with water and aerogel.

[0122] The above polar organic solvent can be used in an appropriate amount by a person skilled in the art, taking into account the degree of hydrophobization in the final silica insulation composite while promoting the surface modification reaction.

[0123] When preparing the above silica sol, the silica precursor composition and the organic solvent may be mixed in a weight ratio of 1:1 to 10, 1:2 to 8, or 1:2 to 6, but are not limited thereto.

[0124] When preparing the above silica sol, an acid catalyst may be further included; specifically, when an alkoxysilane compound other than a hydrolysate is applied as a precursor, an acid catalyst may be further included. In this case, any acid catalyst that lowers the pH to 3 or lower can be used without limitation, and examples include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, or acetic acid. In this case, the acid catalyst may be added in an amount that lowers the pH of the sol to 3 or lower, or it may be added in the form of an aqueous solution dissolved in an aqueous solvent.

[0125] The above catalyst composition may include an inorganic base such as sodium hydroxide or potassium hydroxide as a base catalyst; or an organic base such as ammonium hydroxide. Specific examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia (NH3), ammonium hydroxide (NH4OH; ammonia solution), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), methylamine, ethylamine, isopropylamine, monoisopropylamine, diethylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, choline, monoethanolamine, diethanolamine, 2-aminoethanol, 2-(ethylamino)ethanol, 2-(methylamino)ethanol, N-methyl diethanolamine, dimethylaminoethanol, diethylaminoethanol, nitrilotriethanol, It may be 2-(2-aminoethoxy)ethanol, 1-amino-2-propanol, triethanolamine, monopropanolamine, dibutanolamine, pyridine, or a combination thereof, but is not limited thereto.

[0126] The above base catalyst may be included in an amount such that the pH of the sol becomes 7 to 11. If the pH of the sol falls outside this range, gelation may not be easy or the gelation rate may become excessively slow, potentially leading to reduced processability. Additionally, since the base may precipitate when added in a solid state, it may be preferable to add it in a solution diluted by an aqueous solvent or the aforementioned organic solvent. In this case, the dilution ratio of the base catalyst and the organic solvent, specifically the alcohol, may be 1:4 to 1:100 by volume, but is not limited thereto.

[0127] To prepare the silica sol, the silica precursor composition and the catalyst composition may be mixed in a volume ratio of 1:0.01 to 10.0, 1:0.01 to 5.0, or 1:0.01 to 2.0, but are not limited thereto.

[0128] The structural strength and elasticity of the silica thermal insulation composite can be increased by further including a crosslinking agent, such as diethylene glycol, which can act as a crosslinker during gelation, in the above-mentioned silica sol. The crosslinking agent may be added in an amount of 0.5 to 20 parts by weight, or 0.5 to 15 parts by weight, or 0.5 to 10 parts by weight, or 1 to 8 parts by weight, per 100 parts by weight of silica sol, but is not limited thereto.

[0129] In addition, the structural strength and elasticity of the silica thermal insulation composite can be increased by further including a core-shell rubber (CSR) that imparts elasticity upon gelation to the silica sol described above. The core-shell rubber may be added in an amount of 0.5 to 20 parts by weight, or 0.5 to 15 parts by weight, or 0.5 to 10 parts by weight, or 1 to 8 parts by weight, per 100 parts by weight of silica sol, but is not limited thereto.

[0130] In addition, additives may be added to the silica sol as needed. In this case, any known additives that can be added when manufacturing an aerogel may be applied, and for example, additives such as flame retardants and opacifiers may be used. Such additives may be added in an amount of 0.1 to 10 parts by weight, or 0.1 to 5 parts by weight, or 0.1 to 3 parts by weight, or 0.1 to 1 part by weight per 100 parts by weight of silica sol, but are not limited thereto.

[0131] Gelation step of silica sol

[0132] In the present invention, silica sol can be impregnated into a substrate and then gelled.

[0133] The above impregnation process is a process that allows the catalytic silica sol to penetrate into the internal pores of the substrate. It can be performed by introducing the catalytic silica sol and the substrate into a reaction vessel, or by spraying the catalytic silica sol onto the substrate moving on a conveyor belt according to a roll-to-roll process. At this time, to improve the bonding between the substrate and the silica sol, the substrate can be lightly pressed to ensure sufficient impregnation. Subsequently, the material can be pressed to a certain thickness under a constant pressure to remove excess silica sol, thereby reducing the drying time.

[0134] The temperature of the silica sol in the reaction vessel may be 10 to 40 ℃, 20 to 40 ℃, 25 to 40 ℃, 30 to 40 ℃, or 35 to 45 ℃. It is preferable that the temperature of the silica sol in the reaction vessel satisfies the above range, as the aforementioned viscosity range of the catalyzed sol can be achieved more easily and the desired level of viscosity range can be satisfied even with a relatively short residence time.

[0135] The above-mentioned catalytic silica sol can be impregnated into a substrate. At this time, the catalytic silica sol can be impregnated into the substrate at a volume ratio of 0.1 to 10:1 (catalytic silica sol:substrate), and preferably, impregnating at a volume ratio of 0.3 to 1.5:1, 0.5 to 1.5:1, 0.7 to 1.5:1, or 0.7 to 1.2:1 can improve the strength and elasticity of the gel.

[0136] The silica sol impregnated in the substrate can be gelled simultaneously with the impregnation process of the silica sol or sequentially after the impregnation process.

[0137] The substrate impregnated with the above-mentioned catalystd sol can be gelled on a moving element such as a conveyor belt.

[0138] The above "gelation" may refer to a sol-gel reaction, and the above "sol-gel reaction" may refer to forming a network structure from a silicon unit precursor material. Here, the network structure may refer to a planar net-like structure in which a specific polygon with one or more types of atomic arrangements is connected, or a structure that forms a three-dimensional skeletal structure by sharing vertices, edges, faces, etc. of a specific polyhedron.

[0139] The above gelation is preferably performed at an atmosphere temperature of 20 to 40 ℃ or 25 to 35 ℃ to increase the pore strength of the gel, but is not limited thereto.

[0140] In addition, the gelation time may be performed for 1 to 120 minutes, 1 to 100 minutes, 1 to 60 minutes, 5 to 60 minutes, 5 to 40 minutes, 10 to 40 minutes, 10 to 30 minutes, or 10 to 20 minutes, but is not limited thereto.

[0141] Aging stage of the gelled wet gel complex

[0142] If necessary, the present invention may further include an aging step in which the wet gel composite obtained by gelation as described above is left at an appropriate temperature to allow the chemical change to be completely completed. In the aging step, the network structure formed by gelation can be made more robust, thereby further improving the mechanical stability of the silica thermal insulation composite.

[0143] The above aging step can be performed by leaving the gelled wet gel complex as is at an appropriate temperature, or by adding a cross-linking promoting compound.

[0144] During the above aging step, in the presence of the above wet gel composite, a solution of a base catalyst such as sodium hydroxide (NaOH), potassium hydroxide (KOH), water ammonia (NH4OH), triethylamine, or pyridine diluted in an organic solvent to a concentration of 1 to 20 weight% or 1 to 10 weight% may be added. In this case, Si-O-Si bonds are induced to the maximum extent within the silica network structure (e.g., aerogel), making the network structure of the silica gel more robust and facilitating the maintenance of the pore structure during the subsequent drying process. At this time, the organic solvent may be the aforementioned alcohol, and specifically, may include ethanol.

[0145] In addition, during the aging step, a mixed solution of an alkoxysilane compound and an alcohol can be added to provide not only unreacted sol but also an additional sol precursor source, thereby inducing additional gelation in the silica gel network structure and further strengthening the gel structure. At this time, the alkoxysilane compound may be included in an amount of 0.5 to 9.5 parts by weight, 1.0 to 9.5 parts by weight, or 1.5 to 9.5 parts by weight relative to 100 parts by weight of the total aging solution.

[0146] The above alkoxysilane compounds are tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), methyl triethyl orthosilicate, dimethyl diethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropyl orthosilicate, tetrabutyl orthosilicate, tetrasecondary butyl orthosilicate, tetratertiary butyl orthosilicate, tetrahexyl orthosilicate, and tetracyclohexyl It may include one or more selected from the group consisting of tetracyclohexyl orthosilicate, tetradodecyl orthosilicate, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), trimethylsilanol (TMS), trimethylchlorosilane (TMCS), ethyltriethoxysilane (ETES), dimethyldiethoxysilane (DMDES), and phenyltriethoxysilane.Preferably, the alkoxysilane compound may be one or more of trimethylethoxysilane (TMES) and dimethyldiethoxysilane (DMDES).

[0147] The above alcohol may specifically be a monohydric alcohol such as methanol, ethanol, isopropanol, butanol, etc.; or a polyhydric alcohol such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and sorbitol, etc., preferably a monohydric alcohol having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, butanol, etc., among which it may be particularly ethanol, but is not limited thereto.

[0148] The above aging step can be performed by leaving the product at a temperature of 30°C to 80°C, 40°C to 80°C, or 50°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 6 hours to strengthen the pore structure, and within this range, it is possible to prevent a decrease in productivity while preventing the loss of solvent due to evaporation, thereby preventing an increase in production costs.

[0149] In addition, the above aging step may be performed by first aging at 30°C to 80°C for 0.1 to 5 hours to strengthen the pore structure, and then by adding a solution in which the above-mentioned base catalyst is diluted in an organic solvent, and second aging may be performed at 30°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours.

[0150] In addition, the above aging step may be performed by first aging as described above to hydrophobize the pores and strengthen the pore structure, and then by adding a mixed solution of an alkoxysilane compound and an alcohol to perform second aging at 30°C to 80°C for 0.1 to 20 hours, 0.5 to 15 hours, 0.5 to 10 hours, 0.5 to 7 hours, or 1 to 5 hours.

[0151] The above aging step may be performed in a separate reaction vessel after recovering the gelled wet gel complex, or it may be performed inside the reaction vessel where the gelling step was performed.

[0152] Surface modification step of aged wet gel complex

[0153] The present invention includes a surface modification step of hydrophobizing the surface of a wet gel complex obtained by gelation as described above or an aged wet gel complex in the presence of a surface modifier.

[0154] The above surface modifier may be any compound that hydrophobicizes the wet gel surface without limitation, such as a silane compound, a siloxane compound, a silanol compound, a silazane compound, or a combination thereof. Specific examples include silane compounds comprising trimethylchlorosilane (TMCS), dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), trimethylethoxysilane (TMES), vinyltrimethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, dimethyldichlorosilane, 3-aminopropyltriethoxysilane, etc.; siloxane compounds comprising polydimethylsiloxane (PDMS), polydiethylsiloxane, or octamethylcyclotetrasiloxane, etc. Silanol-based compounds including trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol, etc.; silazane-based compounds including 1,2-diethyldisilazane, 1,1,2,2-tetramethyldisilazane, 1,1,3,3-tetramethyldisilazane, 1,1,1,2,2,2-hexamethyldisilazane (HMDS), 1,1,2,2-tetraethyldisilazane, or 1,2-diisopropyldisilazane, etc.; or a combination thereof, but not limited thereto.

[0155] The above surface modifier may be used as a solution diluted in an organic solvent. Here, the organic solvent may be an alcohol (organic solvent), and the surface modifier may be diluted to 1 to 15 volume%, 1 to 10 volume%, or 1 to 5 volume% based on the total volume of the diluted solution.

[0156] In addition, the surface modifier may be added in an amount of 0.01 to 95 volume%, 0.1 to 90 volume%, 1 to 90 volume%, 10 to 90 volume%, 50 to 90 volume%, or 70 to 90 volume% with respect to the wet gel composite for a sufficient surface modification effect, but is not limited thereto.

[0157] The surface modification step may be performed for 1 to 24 hours at a temperature of 50 to 90 ℃ or 50 to 80 ℃, but is not limited thereto.

[0158] drying stage

[0159] The present invention may include a drying step of drying a surface-modified wet gel composite to obtain a silica thermal insulation composite.

[0160] The above drying is performed as a process that removes only the solvent while maintaining the pore structure of the aged gel, and can be performed, for example, by supercritical drying or atmospheric pressure drying.

[0161] The above supercritical drying process is performed using supercritical carbon dioxide. For example, a matured wet gel complex is placed into a supercritical drying reactor, and then liquid CO2 is filled and a solvent exchange process is performed to replace the alcohol solvent inside the wet gel with CO2. Afterward, the temperature is raised to 40 to 70 ℃ at a constant heating rate, e.g., 0.1 ℃ / min to 1 ℃ / min. Subsequently, a pressure greater than the pressure at which carbon dioxide reaches a supercritical state, e.g. 100 bar to 150 bar, is maintained to maintain the carbon dioxide in a supercritical state for a certain period of time, specifically 20 minutes to 1 hour. Generally, carbon dioxide reaches a supercritical state at a temperature of 31 ℃ and a pressure of 73.8 bar. A silica insulation composite can be manufactured by maintaining the carbon dioxide at a constant temperature and constant pressure for 2 to 12 hours, more specifically 2 to 6 hours, and then gradually removing the pressure to complete the supercritical drying process, but is not limited thereto.

[0162] In addition, the atmospheric pressure drying process may be carried out according to conventional methods such as hot air drying or IR drying at a temperature of 70 to 200 ℃ and atmospheric pressure (1±0.3 atm), but is not limited thereto.

[0163] In the present invention, once the silica insulation composite is prepared as described above, the process may include a step of encapsulating the front surface of the silica insulation composite by surrounding it with a film. For example, the encapsulation process may be performed by cutting a film having an adhesive layer or a film formed on one side into a shape corresponding to the outer surface of the silica insulation composite, and then adhering the film to the surface of the silica insulation composite, particularly the top and bottom surfaces, through the adhesive layer or the film (Fig. 1). As another example, a single film is prepared and then wrapped around the top, side, bottom, and side surfaces of the silica insulation composite along the width direction (Direction A). Additionally, another film is prepared and then wrapped around the top, side, bottom, and side surfaces of the silica insulation composite along the length direction (Direction B). In this case, the film may be prepared by cutting it to a shape and size corresponding to the surface so as to surround all the above surfaces (Figs. 2a, 2b, 2c). Another example involves preparing a single film, placing a silica insulation composite on the film, folding the film, and, if necessary, cutting the film to match the size of the silica insulation composite, and then sealing the outer surface of the film along the periphery of the silica insulation composite by heat-fusion or other methods such as using an adhesive (Fig. 3). Another example involves preparing two films, interposing a silica insulation composite between the two films, and then fusing the film and the silica insulation composite through heat-fusion, or sealing the two layers of film along the outer surface of the silica insulation composite. Another example involves placing a silica insulation composite in the center of a cut film, folding the film according to the shape of the silica insulation composite so that the front surface of the silica insulation composite is completely covered, and sealing the edges of the two overlapping films on one side of the silica insulation composite (Fig. 4). In this case, sealing methods may include heat-fusion, the use of an adhesive, or ultrasonic welding.However, the specific method of encapsulating the silica insulation composite with a film is not particularly limited, and any process used in the industry for the encapsulation or sealing of the silica insulation composite may be included without limitation.

[0164]

[0165] According to another embodiment of the present invention, the invention relates to a battery module or battery pack comprising an insulating member according to the present invention.

[0166] The above battery module may include a module case having an internal space and one or more battery cells existing within the internal space.

[0167] The number of battery cells accommodated in the module case is not limited and can be adjusted according to the application of the battery module. The battery cells accommodated in the module case may be electrically connected to one another. The type of battery cell accommodated in the module case is not limited, but, for example, the battery module may include cylindrical, prismatic, or pouch-type case battery cells.

[0168] The battery module may include an insulating member according to the present disclosure within the module case of the battery module. The insulating member may be located between battery cells accommodated within the module case. The insulating member may be positioned between the module case and a plurality of battery cells, i.e., around the module case. A silica insulating composite located within the module case acts as an insulator to reduce heat propagation within the battery module and improve the safety of the battery module.

[0169] The battery pack may include one or more of the battery modules. In the battery pack, the battery modules may be electrically connected to each other. The battery pack may include an insulating member according to the present disclosure. For example, the insulating member may be located between the battery modules of the battery pack. The insulating member may also at least partially surround a plurality of battery modules within the battery pack. The insulating member may act as an insulating material within the battery pack to reduce heat propagation and improve the safety of the battery pack.

[0170] The present invention is not limited thereto, but may include the following embodiments as examples within the scope of the present invention:

[0171] 1. A silica insulating composite comprising a substrate and a silica network structure comprising a plurality of silica particles and one or more pores; and an insulating member comprising a film positioned on both sides of the silica insulating composite, wherein the insulating member has a thickness recovery rate after compression calculated according to Formula 1 below of 70% or more:

[0172] [Equation 1]

[0173]

[0174] In the above Equation 1, the thickness of the insulating member after the second compression is the thickness of the insulating member measured after first compressing the insulating member until the thickness after compression reaches 50±5% relative to the thickness before compression and maintaining it for 60 minutes, then secondly compressing the insulating member until the thickness reaches 40±5% relative to the thickness before compression and maintaining it for 60 minutes, and then maintaining the environment after removing the pressure for 6 minutes.

[0175] 2. In the first embodiment, after repeating a compression process including first compression and second compression with respect to the insulating member two or more times, the thickness recovery rate (%) of the insulating member may be 68% or more.

[0176] 3. In at least one of the first and second embodiments, the thickness recovery rate (%) of the insulating member may be 68% or more after repeating a compression process including first compression and second compression three times with respect to the insulating member.

[0177] 4. In at least one of the first to third embodiments, the thickness of the insulating member measured after two or more compression processes may be 0.90 times or more the thickness of the insulating member measured after one compression process.

[0178] 5. In at least one of the first to fourth embodiments, the thickness of the insulating member may be 0.5 to 10 mm.

[0179] 6. In at least one of the first to fifth embodiments, the silica particles may comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

[0180] 7. In at least one of the first to sixth embodiments, the silica network structure within the silica thermal insulation composite may comprise particles in which a plurality of silica particles with a particle size greater than 0 and less than or equal to 5 nm are aggregated or bonded.

[0181] 8. In the seventh embodiment, the average particle size of the aggregated or combined particles may be 5 to 2,000 nm.

[0182] 9. In at least one of the first to eighth embodiments, the density of the silica thermal insulation composite is 0.05 to 0.50 g / cm³ 3 It could be.

[0183] 10. In at least one of the first to ninth embodiments, the silica network structure may include silica aerogel or be silica aerogel.

[0184] 11. In at least one of the first to ten embodiments, the silica thermal insulation composite may be an aerogel composite comprising a substrate and a silica aerogel having a plurality of open pores formed therein.

[0185] 12. In at least one of the first to eleventh embodiments, the silica thermal insulation composite may be in the form of a sheet.

[0186] 13. A battery module comprising: one or more battery cells in an internal space; and at least one insulating member of the first to twelfth embodiments.

[0187] 14. The invention relates to a battery pack comprising a battery module comprising one or more battery cells in an internal space; and at least one insulating member of the first to twelfth embodiments.

[0188]

[0189] The present invention will be explained in detail below through the following examples. However, the following examples are merely illustrative of the present invention, and the scope of the present invention is not limited by the following examples.

[0190]

[0191] Examples

[0192]

[0193] [Preparation Example 1] Preparation of a silica thermal insulation composite

[0194] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower in order to promote hydrolysis. Diethylene glycol (DEG) was added to the silica sol prepared as described above in an amount of 7.2 parts by weight per 100 parts by weight of the silica sol. A base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 was added to the silica sol to prepare a catalyzed sol. After filling an impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 3 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol impregnated the fiber mat at a volume ratio of 0.7:1 (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 30 ℃. After gelation was complete, the wet gel composite was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. A solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the primary aged wet gel composite at 109% of the volume of the wet gel composite, followed by secondary aging in a 75 ℃ oven for 2 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the aged wet gel composite as a surface modification solution at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected.Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0195]

[0196] [Preparation Example 2] Preparation of a silica thermal insulation composite

[0197] A silica precursor composition was prepared by mixing dimethyldiethoxysilane (DMDES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower to promote hydrolysis. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with 33.3 L of the catalytic silica sol, the silica sol was infiltrated into the fibers by passing them through a fiber (basalt fiber mat, 2 mm) as a substrate, ensuring that the silica sol impregnated the fiber mat in a volume ratio of 1:1 (silica sol: fiber). The fibers infiltrated with silica sol after passing through the impregnation tank were gelled while moving along a conveyor belt at a constant speed. At this time, the ambient temperature on the conveyor belt was maintained at 35°C. After gelation was complete, the wet gel composite was aged by leaving it in an ethanol solution at a temperature of 70°C for 1 hour. To the aged wet gel composite, a solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added at 90 vol% based on the volume of the wet gel composite as a surface modification solution, and surface modification was performed at a temperature of 75°C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over 1 hour and 20 minutes; upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, a hydrophobic silica aerogel composite was prepared by venting CO2 over a period of 2 hours.

[0198]

[0199] [Preparation Example 3] Preparation of a silica thermal insulation composite

[0200] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:6 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an aqueous hydrochloric acid (HCl) solution was added to the silica precursor solution so that its pH was approximately 3, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:4 with the hydrated TEOS solution. Hydrochloric acid was added to the silica sol so that its pH was 3 or lower to promote hydrolysis. Diethylene glycol (DEG) was added to the silica sol prepared as above in an amount of 1.2 parts by weight per 100 parts by weight of the silica sol. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. After filling an impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 2 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol impregnated the fiber mat at a volume ratio of 1.1:1 (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 25 ℃. After gelation was complete, the wet gel composite was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. A solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the primary aged wet gel composite at 109% of the volume of the wet gel composite, followed by secondary aging in a 75 ℃ oven for 2 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the aged wet gel composite as a surface modification solution at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 12 hours. 7.A silica wet gel was placed in a 2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70 ℃ over a period of 1 hour and 20 minutes. Once 70 ℃ and 150 bar were reached, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Afterward, CO2 was vented over a period of 2 hours to prepare a hydrophobic silica aerogel composite.

[0201]

[0202] [Preparation Example 4] Preparation of a silica thermal insulation composite

[0203] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower to promote hydrolysis. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with 33.3 L of the catalytic silica sol, the silica sol was infiltrated into the fibers by passing them through a fiber (basalt fiber mat, 2 mm) as a substrate, ensuring that the silica sol impregnated the fiber mat in a volume ratio of 1.2:1 (silica sol: fiber). The fibers infiltrated with silica sol after passing through the impregnation tank were gelled while moving along a conveyor belt at a constant speed. At this time, the ambient temperature on the conveyor belt was maintained at 35 ℃. After gelation was complete, the wet gel complex was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. A mixture of ethanol and ammonia water (volume ratio of 98:2) was prepared and added to the primary aged wet gel complex in an amount 1.6 times the volume of the silica sol, followed by secondary aging in a 70 ℃ oven for 5 hours. To the aged wet gel complex, a surface modification solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added at 90 vol% based on the volume of the wet gel complex, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Afterwards, the temperature inside the extractor was raised to 70 ℃ over 1 hour and 20 minutes, and when 70 ℃ and 150 bar were reached, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection for 20 minutes was repeated 4 times.Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, a hydrophobic silica aerogel composite was prepared by venting CO2 over a period of 2 hours.

[0204]

[0205] [Preparation Example 5] Preparation of a silica thermal insulation composite

[0206] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower in order to promote hydrolysis. Core-shell rubber (CSR) was added to the silica sol prepared as described above in an amount of 7.2 parts by weight per 100 parts by weight of the silica sol. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 3 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol impregnated the fiber mat at a volume ratio of 0.7:1 (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 30 ℃. After gelation was complete, the wet gel composite was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. A solution of 2.9 wt% dimethyldiethoxysilane (DMDES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the first-aged wet gel composite at 109% by volume, and second-aged aging was performed in a 75°C oven for 2 hours. A surface modification solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the aged wet gel composite at 90 vol% by volume, and surface modification was performed at a temperature of 75°C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected.Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0207]

[0208] [Preparation Example 6] Preparation of a silica thermal insulation composite

[0209] A silica precursor composition was prepared by mixing dimethyldiethoxysilane (DMDES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower in order to promote hydrolysis. Core-shell rubber (CSR) was added to the silica sol prepared as described above in an amount of 1.2 parts by weight per 100 parts by weight of the silica sol. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 3 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 25 ℃. After gelation was complete, the wet gel composite was stabilized at room temperature (25 ℃) for 10 minutes, followed by a first aging process in a 70 ℃ oven for 30 minutes. A mixture of ethanol and ammonia water (volume ratio of 98:2) was prepared and added to the first-aged wet gel composite in an amount 1.6 times the volume of the silica sol, followed by a second aging process in a 70 ℃ oven for 5 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the aged wet gel composite as a surface modification solution at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 °C for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70 °C over 1 hour and 20 minutes, and upon reaching 70 °C and 150 bar, 0.The process of injecting and exhausting CO2 at a rate of 5 L / min and maintaining a stopped CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0210]

[0211] [Preparation Example 7] Preparation of a silica thermal insulation composite

[0212] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower in order to promote hydrolysis. To the silica sol prepared as above, diethylene glycol (DEG) was added in an amount of 1.2 parts by weight per 100 parts by weight of the silica sol, and core-shell rubber (CSR) was added in an amount of 3.6 parts by weight per 100 parts by weight of the silica sol. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) having a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 3 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol impregnated the fiber mat at a volume ratio of 0.7:1 (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 30 ℃. After gelation was complete, the wet gel composite was stabilized at room temperature (25 ℃) for 10 minutes, followed by primary aging in a 70 ℃ oven for 30 minutes. A solution of 2.9 wt% methyltriethoxysilane (MTES) diluted in ethanol with a moisture content of 10 wt% was prepared and added to the primary aged wet gel composite at 109% of the volume of the wet gel composite, followed by secondary aging in a 75 ℃ oven for 2 hours. A solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the aged wet gel composite as a surface modification solution at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 12 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected.Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0213]

[0214] [Comparative Preparation Example 1] Preparation of a silica thermal insulation composite

[0215] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an aqueous hydrochloric acid (HCl) solution was added to the silica precursor solution so that its pH was approximately 2, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:3 to the hydrated TEOS solution. Hydrochloric acid was added to the silica sol so that its pH was 3 or lower to promote hydrolysis. A catalyzed sol was prepared by adding a base catalyst solution (30 wt% ammonia water) in a volume ratio of 99.5:0.5 to the silica sol. After filling the impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 3 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol impregnated the fiber mat at a volume ratio of 0.5:1 (silica sol:fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 30 ℃. To the gelled wet gel composite, a surface modification solution of hexamethyldisilazane (HMDS) diluted in ethanol (5 vol%) was added at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 4 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0216]

[0217] [Comparative Preparation Example 2] Preparation of a silica thermal insulation composite

[0218] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:5 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an aqueous hydrochloric acid (HCl) solution was added so that the pH of the silica precursor solution was approximately 2, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:3 to the hydrated TEOS solution. Hydrochloric acid was added so that the pH of the silica sol was 3 or lower to promote hydrolysis. A catalyzed sol was prepared by adding a base catalyst solution (30 wt% ammonia water) in a volume ratio of 99.5:0.5 to the silica sol. After filling an impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 3 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol was impregnated into the fiber mat at a 1:1 volume ratio (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 25 ℃. After gelation was complete, the wet gel composite was aged by leaving it in an ethanol solution at a temperature of 70 ℃ for 1 hour. To the aged wet gel composite, a surface modification solution of hexamethyldisilazane (HMDS) diluted in ethanol (5 vol%) was added at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 ℃ for 4 hours. A silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70 ℃ over 1 hour and 20 minutes. When 70 ℃ and 150 bar were reached, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge.Subsequently, a hydrophobic silica aerogel composite was prepared by venting CO2 over a period of 2 hours.

[0219]

[0220] [Comparative Preparation Example 3] Preparation of a silica thermal insulation composite

[0221] A silica precursor solution was prepared by mixing tetraethyl orthosilicate (TEOS) and water in a molar ratio of 1:4 and adding ethanol in a weight ratio of 1:1 with TEOS. To promote the hydrolysis of the silica precursor solution, an aqueous hydrochloric acid (HCl) solution was added to the silica precursor solution so that its pH was approximately 3, and the mixture was stirred for at least 2 hours to prepare a hydrated TEOS solution. A silica sol was prepared by adding ethanol in a weight ratio of 1:6 with the hydrated TEOS solution. Hydrochloric acid was added to the silica sol so that its pH was 3 or lower to promote hydrolysis. A catalyzed sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 with the silica sol. After filling the impregnation tank with 33.3 L of catalyzed silica sol, a fiber (basalt fiber mat, 2 mm) was passed through as a substrate to infiltrate the silica sol into the fiber, ensuring that the silica sol was impregnated into the fiber mat at a volume ratio of 1:1 (silica sol: fiber). The fiber, infiltrated with silica sol after passing through the impregnation tank, was gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 25 ℃. After gelation was complete, a solution was prepared by diluting 2.9 wt% of methyltriethoxysilane (MTES) in ethanol with a moisture content of 10 wt%, and this solution was added at 109% of the volume of the wet gel composite. The mixture was then aged in a 75 ℃ oven for 1 hour. A solution of hexamethyldisilazane (HMDS) diluted in ethanol (5 vol%) was added to the aged wet gel composite as a surface modification solution at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75 °C for 4 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70 °C over 1 hour and 20 minutes, and upon reaching 70 °C and 150 bar, 0.The process of injecting and exhausting CO2 at a rate of 5 L / min and maintaining a stopped CO2 injection for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and exhaust. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0222]

[0223] [Comparative Preparation Example 4] Preparation of a silica thermal insulation composite

[0224] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower in order to promote hydrolysis. A catalytic sol was prepared by adding a base catalyst solution (30 wt% ammonia water) having a volume ratio of 99.5:0.5 to the silica sol. After filling 33.3 L of the catalytic silica sol into an impregnation tank, the silica sol was infiltrated into the fibers by passing the sol through a fiber (basalt fiber mat, 2 mm) as a substrate, such that the silica sol impregnated the fiber mats at a volume ratio of 0.7:1 (silica sol: fiber). Fibers infiltrated with silica sol after passing through an impregnation tank were gelled while moving along a conveyor belt at a constant speed. During this process, the ambient temperature on the conveyor belt was maintained at 30°C. After gelation was complete, the wet gel composite was aged by leaving it in an ethanol solution at 70°C for 1 hour. To the aged wet gel composite, a surface modification solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at 75°C for 4 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over a period of 1 hour and 20 minutes. Upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, CO2 was vented over a period of 2 hours to produce a hydrophobic silica aerogel composite.

[0225]

[0226] [Comparative Preparation Example 5] Preparation of a silica thermal insulation composite

[0227] A silica precursor composition was prepared by mixing methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) in a molar ratio of 97:3. A silica sol was prepared by mixing the silica precursor composition with water in a molar ratio of 1:10 and mixing the silica precursor composition with ethanol in a weight ratio of 1:2. Hydrochloric acid was added to the silica sol to lower the pH to 3 or lower to promote hydrolysis. A catalytic sol was prepared by adding a base catalyst solution (5 wt% NaOH aqueous solution) in a volume ratio of 99:1 to the silica sol. After filling an impregnation tank with 33.3 L of the catalytic silica sol, the silica sol was infiltrated into the fibers by passing them through a fiber (basalt fiber mat, 3 mm) as a substrate, ensuring that the silica sol impregnated the fiber mat at a volume ratio of 0.5:1 (silica sol: fiber). The fibers infiltrated with silica sol after passing through the impregnation tank were gelled while moving along a conveyor belt at a constant speed. At this time, the ambient temperature on the conveyor belt was maintained at 25°C. After gelation was complete, a solution of trimethylethoxysilane (TMES) diluted in ethanol (10 vol%) was added to the wet gel composite as a surface modification solution at 90 vol% based on the volume of the wet gel composite, and surface modification was performed at a temperature of 75°C for 6 hours. The silica wet gel was placed in a 7.2 L supercritical extractor, and CO2 was injected. Subsequently, the temperature inside the extractor was raised to 70°C over 1 hour and 20 minutes; upon reaching 70°C and 150 bar, CO2 was injected and discharged at a rate of 0.5 L / min for 20 minutes, and the process of stopping CO2 injection and maintaining the state for 20 minutes was repeated 4 times. Ethanol was recovered through the bottom of the separator during CO2 injection and discharge. Subsequently, a hydrophobic silica aerogel composite was prepared by venting CO2 over a period of 2 hours.

[0228]

[0229] [Examples 1 to 7 and Comparative Examples 1 to 5] Manufacture of thermal insulation members

[0230] Specimens were prepared such that the width x length of the silica insulation composites prepared in Manufacturing Examples 1 to 7 and Comparative Manufacturing Examples 1 to 5 were approximately 60 cm x 12 cm. As a film to surround the silica insulation composite, a PET film (25 μm) with an acrylic adhesive applied to one side to a thickness of approximately 50 μm was prepared. After placing the silica insulation composite on the center of this PET film, the film was folded to surround the front of the silica insulation composite as shown in Fig. 4, and the overlapping parts of the film were sealed with an adhesive to manufacture an insulation member.

[0231]

[0232] [Experimental Example 1] Evaluation of Restoration Recovery Rate After Compression

[0233] The following experiment was performed to evaluate the recovery rate of the silica insulation composite according to the volume change of the cell when the silica insulation composite manufactured according to the present invention was applied as an insulation member for a battery.

[0234] 1. Evaluation of thickness recovery rate after a single compression process

[0235] First, the silica insulation composites with attached films prepared in Examples 1 to 7 and Comparative Examples 1 to 5 were cut to prepare five specimens each with dimensions of 5 mm x 5 mm. Specifically, four specimens were obtained by positioning the exact center of the specimen at a distance of 10 cm from the corners of each silica insulation composite in the direction of the center, and one specimen was obtained by positioning the exact center of the silica insulation composite at the exact center of the specimen. The specimens were placed between circular compression jigs (diameter approximately 10 cm) of a UTM machine (Instron Model 5659), and the height of the compression jig was adjusted at a speed of 8 mm / min to apply a pressure of 2 kPa to the specimens, thereby measuring the initial thickness of the samples. After applying pressure at a speed of 8 mm / min to achieve a thickness of 50 (±5)% of the measured initial thickness, the said thickness was maintained for 60 minutes. Next, additional pressure was applied at a speed of 8 mm / min to achieve a thickness of 40 (±5)% of the initial thickness, and this thickness was maintained for 60 minutes. Subsequently, the compression jig was adjusted at a speed of 8 mm / min so that the pressure applied to the specimen became zero. After maintaining this state for 6 minutes, the height of the compression jig was adjusted at a speed of 8 mm / min to apply a pressure of 2 kPa to the specimen, and the final thickness of the specimen was measured. For each example, the average value of the initial thickness and the average value of the thickness after secondary compression were calculated for five specimens, and these values ​​were substituted into Equation 1 to obtain the thickness recovery rate. The thickness recovery rate was rounded to the first decimal place and is shown in Table 2.

[0236] [Equation 1]

[0237]

[0238] Initial Thickness (mm) Thickness After 1 Compression Process (mm) Thickness Recovery Rate (%) Example 1 2.9 12.6 792% Example 2 2.09 1.5 675% Example 3 2.33 1.7 73% Example 4 2.58 2.1 383% Example 5 2.9 2.6 993% Example 6 3.07 2.6 285% Example 7 2.69 2.5 294% Comparative Example 1 2.26 1.4 62% Comparative Example 2 3.26 1.9 861% Comparative Example 3 2.13 1.4 669% Comparative Example 4 1.95 1.3 67% Comparative Example 5 2.33 1.6 169%

[0239] As shown in Table 1 above, the silica thermal insulation composite according to the present invention (Examples 1 to 7) showed a high thickness recovery rate of 73% or more even after a two-stage compression process. However, the silica thermal insulation composites of Comparative Examples 1 to 5 showed a thickness recovery rate of only around 60% after a two-stage compression process.

[0240] 2. Evaluation of thickness recovery rate after repeated compression process

[0241] To evaluate whether the silica thermal insulation composite manufactured according to the present invention maintains an excellent recovery rate even with repeated volume changes of the cell during battery operation, the compression process of 1. above was repeated three times. Specifically, the initial thickness of the specimen was measured, and pressure was applied to reach 50% of the initial thickness, followed by additional pressure to reach 40% of the thickness. Then, the pressure was lowered again to reach 50% of the initial thickness, followed by additional pressure to reach 40% of the thickness. Subsequently, the pressure was lowered again to reach 50% of the initial thickness, followed by additional pressure to reach 40% of the thickness. Afterward, the compression jig was adjusted so that the pressure applied to the specimen became zero, and the final thickness of the specimen was measured. For each example, the average value of the initial thickness and the average value of the thickness after repeating the compression process three times were calculated for five specimens, and these values ​​were substituted into Equation 1 to obtain the thickness recovery rate. The thickness recovery rate is shown in Table 2 as a result rounded to the first decimal place.

[0242] Initial thickness (mm) Thickness after 1 compression process (mm) Thickness after 3 compression processes (mm) Thickness Recovery Rate (%) Example 1 2.9 12.6 72.5 989% Example 2 2.0 9 1.5 6 1.5 172% Example 3 2.3 31.7 1.6 872% Example 4 2.5 8 2.1 31.9 274% Example 5 2.9 2.6 9 2.6 290% Example 6 3.0 7 2.6 22.4 79% Example 7 2.6 9 2.5 22.4 89% Comparative Example 1 2.2 6 1.4 1.1 250% Comparative Example 2 3.2 6 1.9 8 1.7 654% Comparative Example 3 2.1 31.4 6 1.4 66% Comparative Example 4 1.9 5 1.3 1.1 559% Comparative Example 5 2.3 31.6 11.3 156%

[0243] As shown in Table 2 above, the silica insulation composites according to the present invention (Examples 1 to 7) showed a high thickness recovery rate of 72% or more even after repeating the two-stage compression process three times. However, the silica insulation composites of Comparative Examples 1 to 5 showed a thickness recovery rate of mostly only around 50% after repeating the two-stage compression process three times. Through the above experiments, it was found that the insulation material containing the silica insulation composite according to the present invention has excellent elastic recovery properties against multi-stage compression, effectively accommodating periodic volume changes of the cell that occur during the charging and discharging process of the battery, thereby suppressing the deterioration of insulation performance.

[0244] [Explanation of the symbol]

[0245] 100: Silica insulation composite

[0246] 200, 200': Film

[0247] S1, S2: Sealing part

[0248] The present invention relates to an insulating material that can be applied as an insulating material for batteries, and can also be used as an insulating material, thermal insulation material, or non-combustible material in the construction, aviation, automotive, home appliance, semiconductor, or industrial equipment fields.

Claims

1. A silica thermal insulation composite comprising a substrate and a silica network structure comprising a plurality of silica particles and one or more pores; and a thermal insulation member comprising films located on both sides of the silica thermal insulation composite. The above insulating member is an insulating member having a thickness recovery rate after compression of 70% or more calculated according to the following Equation 1: [Equation 1] In the above Equation 1, the thickness of the insulating member after the second compression is the thickness of the insulating member measured after first compressing the insulating member until the thickness after compression reaches 50±5% relative to the thickness before compression and maintaining it for 60 minutes, then secondly compressing the insulating member until the thickness reaches 40±5% relative to the thickness before compression and maintaining it for 60 minutes, and then maintaining the environment after removing the pressure for 6 minutes.

2. In Paragraph 1, An insulating member having a thickness recovery rate (%) of 68% or more after repeating a compression process including first compression and second compression two or more times with respect to the insulating member.

3. In Paragraph 1, An insulating member having a thickness recovery rate (%) of 68% or more after repeating a compression process including first compression and second compression three times for the insulating member.

4. In Paragraph 2, An insulating member in which the thickness of the insulating member measured after two or more compression processes is at least 0.90 times the thickness of the insulating member measured after one compression process.

5. In Paragraph 1, An insulating member having a thickness of 0.5 to 10 mm.

6. In Paragraph 1, An insulating member wherein the silica particles comprise silica, methylsilylated silica, dimethylsilylated silica, trimethylsilylated silica, or a mixture thereof.

7. In Paragraph 1, An insulating member in which the silica network structure within the above silica insulating composite comprises particles in which a plurality of silica particles having a particle size greater than 0 and less than or equal to 5 nm are aggregated or bonded.

8. In Paragraph 7, An insulating member having an average particle size of the aggregated or bonded particles of 5 to 2,000 nm.

9. In Paragraph 1, The density of the above silica thermal insulation composite is 0.05 to 0.50 g / cm³ 3 Phosphorus, insulating member.

10. A battery module comprising: one or more battery cells in an internal space; and an insulating member of any one of claims 1 to 9.

11. A battery pack comprising the battery module of claim 10.

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