Aerogel composites, methods of making and using the same

Abstract

The application relates to an aerogel composite material and a preparation method and application thereof, the preparation method comprising the following steps: sequentially stacking a first glass fiber mat, a ceramic fiber mat and a second glass fiber mat to obtain a first composite structure, wherein the thickness ratio of the first glass fiber mat, the ceramic fiber mat and the second glass fiber mat is 1:(1.5-3):(0.5-2); performing impregnation treatment on the first composite structure in an aerogel precursor sol to obtain a second composite structure; sequentially performing a gelation reaction and aging treatment on the second composite structure to obtain a third composite structure; and performing drying treatment on the third composite structure to obtain the aerogel composite material. The preparation method can realize effective combination between fiber mats with different characteristics, can fully exert the advantages of glass fibers and ceramic fibers, and can prepare the aerogel composite material with excellent mechanical structural strength and heat insulation performance.

Description

Technical Field

[0001] This application relates to the field of thermal insulation materials technology, and in particular to aerogel composite materials, their preparation methods and applications. Background Technology

[0002] With the rapid development of the new energy industry, the energy density and integration of lithium-ion battery packs are constantly improving, and their safety issues are receiving increasing attention. Thermal runaway is one of the main causes of battery pack fires and explosions. Currently, a common countermeasure is to install highly efficient thermal protection materials between cells or modules to suppress thermal spread.

[0003] Aerogel composites are considered ideal battery insulation materials due to their extremely low thermal conductivity and excellent flame-retardant properties. Currently, glass fiber mat and ceramic fiber mat are two common skeleton materials used in the preparation of aerogel composites for battery packs. Glass fiber mat has good flexibility but limited temperature resistance; ceramic fiber mat can withstand extremely high temperatures but is prone to cracking and powdering. To combine the advantages of both materials, traditional techniques attempt to composite different types of mats. However, due to the significant differences in the physicochemical properties of glass fiber mat and ceramic fiber mat, including their different surface characteristics, coefficients of thermal expansion, and hydrophilicity / hydrophobicity, an effective and reliable combination is impossible. This results in aerogel composites failing to achieve both good thermal insulation and excellent structural strength. Summary of the Invention

[0004] To address the aforementioned issues, this application provides an aerogel composite material with good thermal insulation and structural strength, its preparation method, and its application.

[0005] In a first aspect, this application provides a method for preparing an aerogel composite material.

[0006] A method for preparing an aerogel composite material includes the following steps:

[0007] A first composite structure is obtained by sequentially stacking a first glass fiber mat, a ceramic fiber mat, and a second glass fiber mat, wherein the thickness ratio of the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat is 1:(1.5~3):(0.5~2).

[0008] The first composite structure was immersed in an aerogel precursor sol for impregnation treatment to obtain the second composite structure.

[0009] The second composite structure was subjected to gelation reaction and aging treatment in sequence to obtain the third composite structure;

[0010] The third composite structure is dried to obtain the aerogel composite material.

[0011] In some embodiments, the thickness of the first glass fiber mat is 0.5 mm to 3 mm;

[0012] And / or, the thickness of the second glass fiber mat is 0.5 mm to 3 mm;

[0013] And / or, the thickness of the ceramic fiber felt is 1mm to 5mm; and / or

[0014] The thickness of the first composite structure is 2mm to 9mm.

[0015] In some embodiments, the areal density of the first glass fiber mat is 100 g / m³. 2 ~300g / m 2 ;

[0016] And / or, the areal density of the second glass fiber mat is 100 g / m². 2 ~300g / m 2 ;

[0017] And / or, the areal density of the ceramic fiber felt is 150 g / m³. 2 ~400g / m 2 .

[0018] In some embodiments, the aging process includes the following steps:

[0019] The second composite structure was left to stand at 40℃~60℃ for 2h~12h, and then aged in an aging solution at 50℃~70℃ for 12h~24h, wherein the aging solution included ethanol.

[0020] In some embodiments, the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all wet-laid fiber mats; and / or

[0021] The first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all pretreated, and the pretreatment steps include baking at 300℃~500℃ for 1h~2h.

[0022] In some embodiments, the aerogel precursor sol comprises silica sol, and the method for preparing the silica sol includes:

[0023] Tetraethyl orthosilicate, ethanol, water, and hydrochloric acid are mixed in a molar ratio of 1:(6~10):(3~5):(0.0005~0.002) and hydrolyzed to form a prepolymer solution;

[0024] The pH of the prepolymer solution is adjusted to 7-8, and the silica sol is formed by condensation polymerization.

[0025] In some embodiments, the drying process employs supercritical drying, the steps of which include:

[0026] The third composite structure was wrapped with a mesh cloth, and ethanol was injected into a high-pressure reactor. The reactor was then kept at 240℃~260℃ and 6MPa~8MPa for 2h~4h.

[0027] In some embodiments, the mesh size of the mesh fabric is 0.5mm to 2mm.

[0028] In a second aspect, this application provides an aerogel composite material.

[0029] An aerogel composite material is prepared using the above-described method for preparing aerogel composite materials.

[0030] In a third aspect, this application provides an aerogel composite material prepared by the above-described aerogel composite material preparation method, or the application of the above-described aerogel composite material in the field of battery thermal insulation.

[0031] The method for preparing aerogel composite material provided in this application involves sequentially stacking a first glass fiber mat, a ceramic fiber mat, and a second glass fiber mat to construct a sandwich structure and controlling the thickness of the three to be in a specific ratio. The first composite structure is then subjected to an integrated impregnation, gelation, and aging treatment. This method can achieve effective bonding between fiber mats with different properties, thereby fully leveraging the advantages of glass fiber and ceramic fiber to obtain an aerogel composite material that combines excellent mechanical structural strength and thermal insulation performance.

[0032] By forming a first composite structure with a specific structure, the excellent flexibility and flexural strength of glass fiber felt can be utilized to enclose the overall composite structure, improving its integrity and compensating for the mechanical shortcomings of ceramic fiber felt, such as fragility and powder shedding. Furthermore, by designing a thicker ceramic fiber felt in the middle, a sufficient thermal insulation base can be provided for the gel composite material, effectively blocking heat spread. Simultaneously, the first composite structure undergoes integrated impregnation, gelation, and aging treatments. The sol penetrates and crosses the interfaces of different fiber felts, growing a continuous, interface-free aerogel network between layers. This effectively connects the interfaces of different fiber felts, resulting in an aerogel composite material with good structural integrity. Moreover, the aerogel composite material preparation method provided in this application achieves excellent bonding strength without introducing adhesives during composite molding, resulting in a product free of adhesive residue. This avoids the defects caused by adhesives, such as easy decomposition at high temperatures and the release of fumes. The resulting aerogel composite material is particularly suitable for applications such as battery packs. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of the aerogel composite material in one embodiment of this application.

[0035] Explanation of reference numerals in the attached figures:

[0036] 100, First composite layer; 200, Second composite layer; 300, Third composite layer. Detailed Implementation

[0037] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0038] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. In this application, "at least one" means one or more, such as one, two, or more than two. "Multiple" or "several" means at least two, such as two, three, etc.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0041] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0042] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0043] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0044] The first aspect of this application provides a method for preparing an aerogel composite material with good thermal insulation and structural strength.

[0045] For example, a method for preparing aerogel composite materials includes the following steps:

[0046] A first composite structure is obtained by sequentially stacking a first glass fiber mat, a ceramic fiber mat, and a second glass fiber mat, wherein the thickness ratio of the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat is 1:(1.5~3):(0.5~2).

[0047] The first composite structure was immersed in an aerogel precursor sol for impregnation treatment to obtain the second composite structure.

[0048] The second composite structure was subjected to gelation reaction and aging treatment in sequence to obtain the third composite structure;

[0049] The third composite structure was dried to obtain an aerogel composite material.

[0050] In the aforementioned method for preparing aerogel composite materials, a sandwich structure is constructed by sequentially stacking a first glass fiber mat, a ceramic fiber mat, and a second glass fiber mat, controlling the thickness of the three layers to a specific ratio. The first composite structure undergoes integrated impregnation, gelation, and aging treatments. Through the synergistic combination of the specific structure and gelation process, effective bonding between fiber mats with different properties can be achieved, thereby fully leveraging the advantages of both glass and ceramic fibers to produce an aerogel composite material with excellent mechanical strength and thermal insulation properties. Specifically, by forming a first composite structure with a specific structure, the excellent flexibility and flexural strength of the glass fiber mat can be utilized to enclose the overall composite structure, improving its integrity and compensating for the mechanical shortcomings of the ceramic fiber mat, such as fragility and powder shedding. Furthermore, by designing a relatively thick ceramic fiber mat in the middle, a sufficient thermal insulation foundation can be provided for the aerogel composite material, effectively blocking heat propagation. Simultaneously, the first composite structure undergoes integrated impregnation, gelation reaction, and aging treatment. The sol penetrates and crosses the interfaces of different fiber felts, growing a continuous, interface-free aerogel network between layers. This effectively connects the interfaces of different fiber felts, resulting in an aerogel composite material with excellent structural integrity. Furthermore, the aerogel composite material preparation method provided in this application achieves excellent bonding strength without introducing binders during composite molding, resulting in a product free of binder residue. This avoids the defects caused by binders, such as easy decomposition at high temperatures and release of fumes. The resulting aerogel composite material is particularly suitable for applications such as battery packs.

[0051] In this embodiment, the thickness ratio of the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat can be, but is not limited to, other values ​​within the range of 1:1.5:0.5, 1:2:0.5, 1:2.5:0.5, 1:3:0.5, 1:2:1, 1:2.5:1, 1:3:1, 1:1.5:1.5, 1:2:1.5, 1:2.5:1.5, 1:3:1.5, 1:3:2, or 1:(1.5~3):(0.5~2).

[0052] In some embodiments, the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all wet-laid fiber mats.

[0053] In some embodiments, the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all pretreated. The pretreatment step includes baking at 300℃~500℃ for 1h~2h. Pretreatment removes organic wetting agents from the surface of the fiber mats, preventing them from affecting the gelation process.

[0054] In some embodiments, the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all pretreated. The pretreatment step includes baking at 300°C to 500°C for 1 to 2 hours. The purpose of the pretreatment is to remove organic sizing agents from the surface of the fiber mat.

[0055] In some embodiments, the thickness of the first glass fiber mat is 0.5 mm to 3 mm. Optionally, the thickness of the first glass fiber mat can be, but is not limited to, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or other values ​​within the range of 0.5 mm to 3 mm.

[0056] In some embodiments, the thickness of the second fiberglass mat is 0.5 mm to 3 mm. Optionally, the thickness of the second fiberglass mat can be, but is not limited to, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or other values ​​within the range of 0.5 mm to 3 mm.

[0057] In some embodiments, the thickness of the ceramic fiber felt is 1 mm to 5 mm. Optionally, the thickness of the ceramic fiber felt can be, but is not limited to, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or other values ​​within the range of 1 mm to 5 mm.

[0058] In some embodiments, the thickness of the first composite structure is 2 mm to 9 mm.

[0059] In the above embodiments, by controlling the first glass fiber mat, the second glass fiber mat, and the ceramic fiber mat to be within the above thickness range, on the one hand, it helps the glass fiber and ceramic fiber to maintain their basic inherent properties; on the other hand, it helps to form a highly integrated aerogel skeleton structure between the first glass fiber mat and the second glass fiber mat, which helps to avoid the problems of incomplete sol penetration and local discontinuity of the aerogel skeleton caused by the first composite structure being too thick.

[0060] In some embodiments, the thickness ratio of the first glass fiber mat to the second glass fiber mat is 1:(0.8~1.2); the thickness ratio of the ceramic fiber mat to the total thickness of the first and second glass fiber mats is 2:(1.5~2.2). Studies have shown that maintaining the above thickness ratios is more conducive to forming an aerogel composite material with a strong integral structure and sufficient thermal insulation performance.

[0061] In some embodiments, the areal density of the first glass fiber mat is 100 g / m². 2 ~300g / m 2 Optionally, the areal density of the first glass fiber mat can be, but is not limited to, 100 g / m². 2200g / m 2 300g / m 2 Or 100g / m 2 ~300g / m 2 Other values ​​within the range.

[0062] In some embodiments, the areal density of the second glass fiber mat is 100 g / m². 2 ~300g / m 2 Optionally, the areal density of the second glass fiber mat can be, but is not limited to, 100 g / m². 2 200g / m 2 300g / m 2 Or 100g / m 2 ~300g / m 2 Other values ​​within the range.

[0063] In some embodiments, the areal density of the ceramic fiber felt is 150 g / m³. 2 ~400g / m 2 Optionally, the areal density of the ceramic fiber felt can be, but is not limited to, 150 g / m². 2 200g / m 2 300g / m 2 400g / m 2 Or 150g / m 2 ~400g / m 2 Other values ​​within the range.

[0064] In the above embodiments, by controlling the first glass fiber mat, the second glass fiber mat, and the ceramic fiber mat to be within the above-mentioned areal density range, it is helpful to enable the sol to effectively penetrate the first composite structure, which helps to form a cross-layer aerogel network, thereby improving the interlayer bonding strength and the overall integrity of the material.

[0065] In some embodiments, the impregnation process includes:

[0066] The first composite structure was immersed in the aerogel precursor sol and impregnated under vacuum or normal pressure for 10 to 30 minutes.

[0067] In some embodiments, the gelation reaction and aging treatment steps include:

[0068] The second composite structure was left to stand at 40℃~60℃ for 2h~12h, and then aged in an aging solution at 50℃~70℃ for 12h~24h, the aging solution including ethanol.

[0069] In this embodiment, by standing at 40℃~60℃ for 2h~12h, the gel skeleton can be initially shaped under relatively mild conditions; then, aging in an aging solution at 50℃~70℃ for 12h~24h can promote further condensation of unreacted silanol groups, which helps to improve the strength of the gel network.

[0070] In some embodiments, the aerogel precursor sol includes silica sol.

[0071] In some embodiments, the method for preparing silica sol includes:

[0072] Tetraethyl orthosilicate, ethanol, water, and hydrochloric acid are mixed in a molar ratio of 1:(6~10):(3~5):(0.0005~0.002) and hydrolyzed to form a prepolymer solution;

[0073] The pH of the prepolymer solution is adjusted to 7-8, and silica sol is formed through condensation.

[0074] Studies have shown that silica sol prepared by mixing tetraethyl orthosilicate, ethanol, water, and hydrochloric acid in the above molar ratio exhibits excellent compatibility with the first glass fiber mat, ceramic fiber mat, and second glass fiber mat, which helps to improve the structural strength of aerogel composite materials.

[0075] In some embodiments, the drying process employs supercritical drying, and the supercritical drying steps include:

[0076] The third composite structure was wrapped with mesh cloth, and ethanol was injected into the autoclave. The autoclave was maintained at 240℃~260℃ and 6MPa~8MPa for 2h~4h.

[0077] Studies have shown that wrapping the third composite structure with a mesh fabric before drying helps to constrain shrinkage stress during the drying process, effectively suppressing warping, delamination, or cracking caused by differences in shrinkage between layers. This is particularly beneficial for improving the yield of large-size products, especially aerogel composites with lengths and widths greater than 200 mm. Optionally, the mesh fabric can be polyamide mesh fabric, polytetrafluoroethylene mesh fabric, stainless steel wire mesh fabric, or nylon mesh fabric. Furthermore, drying under supercritical conditions of 240℃~260℃ and 6MPa~8MPa allows the ethanol within the pores to reach a supercritical state, removing the solvent from the gel network while fully preserving the nanoporous structure of the aerogel. This contributes to achieving lower thermal conductivity and better structural strength in the aerogel composite material.

[0078] In some embodiments, the mesh size of the mesh fabric is 0.5mm to 2mm.

[0079] In some embodiments, the drying process employs atmospheric pressure drying, and the atmospheric pressure drying steps include:

[0080] The third composite structure was wrapped with a mesh cloth and dried sequentially at 55℃~65℃ for 6h~12h, at 75℃~85℃ for 6h~12h, at 95℃~105℃ for 6h~12h, and finally at 140℃~160℃ for 2h~4h.

[0081] In a second aspect, this application provides an aerogel composite material prepared using the aforementioned method for preparing aerogel composite materials.

[0082] For example, please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an aerogel composite material according to one embodiment of this application. In some embodiments, the aerogel composite material includes a first composite layer 100, a second composite layer 200, and a third composite layer 300 stacked sequentially. The first composite layer 100 is obtained by combining a first glass fiber mat with aerogel, the second composite layer 200 is obtained by combining a ceramic fiber mat with aerogel, and the third composite layer 300 is obtained by combining a second glass fiber mat with aerogel.

[0083] In some embodiments, the thermal conductivity of the aerogel composite material at 25°C is 0.02 W / (m·K) to 0.026 W / (m·K).

[0084] In a third aspect, this application provides an aerogel composite material prepared by the above-described aerogel composite material preparation method, or the application of the above-described aerogel composite material in the field of battery thermal insulation.

[0085] The present application will be further described in detail below with reference to specific embodiments.

[0086] Unless otherwise specified, the raw materials used in the following specific embodiments and comparative examples are all commercially available products; the instruments used are all commercially available products; and the processes used are all conventionally selected by those skilled in the art unless otherwise specified.

[0087] Example 1

[0088] This embodiment provides an aerogel composite material.

[0089] The preparation method of aerogel composite material is as follows:

[0090] A first composite structure is obtained by sequentially stacking a first glass fiber mat, a ceramic fiber mat, and a second glass fiber mat, wherein the thickness of both the first and second glass fiber mats is 1 mm and the areal density is 180 g / m³. 2The ceramic fiber felt has a thickness of 2mm and a surface density of 220g / m³. 2 .

[0091] Silica sol was prepared by the sol-gel method. Tetraethyl orthosilicate, ethanol, water and hydrochloric acid were mixed in a molar ratio of 1:8:4:0.001 and stirred at room temperature for 45 min to obtain a prepolymer solution. The pH of the prepolymer solution was then adjusted to 7.5 with 0.1 mol / L ammonia water and stirred for another 10 min to obtain silica sol.

[0092] The first composite structure was immersed in the aerogel precursor sol (silica sol) and vacuum impregnated for 15 min (vacuum degree -0.095 MPa) to obtain the second composite structure.

[0093] The second composite structure was allowed to stand in a constant temperature oven at 50°C for 4 hours to undergo a gelation reaction, and then transferred to an aging solution at 60°C (ethanol and water in a volume ratio of 7:3) for 16 hours to obtain the third composite structure.

[0094] The third composite structure was wrapped with a polyamide mesh with a pore size of 1 mm, placed in a supercritical drying autoclave, injected with ethanol, heated to 250 °C, and dried at a pressure of 7.5 MPa for 3 h. After depressurization, the structure was removed, the mesh was removed, and the aerogel composite material was obtained.

[0095] Example 2

[0096] This embodiment provides an aerogel composite material.

[0097] The difference between this embodiment and Embodiment 1 is that:

[0098] The third composite structure was wrapped with stainless steel mesh and dried using an atmospheric pressure drying process. The aerogel composite material was obtained by drying it in an oven at atmospheric pressure at 60℃ for 12 hours, 80℃ for 12 hours, 100℃ for 10 hours, and 150℃ for 4 hours.

[0099] Example 3

[0100] This embodiment provides an aerogel composite material.

[0101] The difference between this embodiment and Embodiment 1 is that:

[0102] Silica sol was prepared by the sol-gel method. Tetraethyl orthosilicate, ethanol, water and hydrochloric acid were mixed in a molar ratio of 1:6:3:0.001 and stirred at room temperature for 45 min to obtain a prepolymer solution. The pH of the prepolymer solution was then adjusted to 7.5 with 0.1 mol / L ammonia water and stirred for another 10 min to obtain silica sol.

[0103] Example 4

[0104] This embodiment provides an aerogel composite material.

[0105] The difference between this embodiment and Embodiment 1 is that:

[0106] Silica sol was prepared by the sol-gel method. Tetraethyl orthosilicate, ethanol, water and hydrochloric acid were mixed in a molar ratio of 1:10:5:0.001 and stirred at room temperature for 45 min to obtain a prepolymer solution. The pH of the prepolymer solution was then adjusted to 7.5 with 0.1 mol / L ammonia water and stirred for another 10 min to obtain silica sol.

[0107] Example 5

[0108] This embodiment provides an aerogel composite material.

[0109] The difference between this embodiment and Embodiment 1 is that:

[0110] Silica sol was prepared by the sol-gel method. Tetraethyl orthosilicate, ethanol, water and hydrochloric acid were mixed in a molar ratio of 1:8:6:0.001 and stirred at room temperature for 45 min to obtain a prepolymer solution. The pH of the prepolymer solution was then adjusted to 7.5 with 0.1 mol / L ammonia water and stirred for another 10 min to obtain silica sol.

[0111] Example 6

[0112] This embodiment provides an aerogel composite material.

[0113] The difference between this embodiment and Embodiment 1 is that:

[0114] The thickness of the first glass fiber mat is 2mm, the thickness of the second glass fiber mat is 2mm, and the thickness of the ceramic fiber mat is 4mm.

[0115] Example 7

[0116] This embodiment provides an aerogel composite material.

[0117] The difference between this embodiment and Embodiment 1 is that:

[0118] The thickness of the first glass fiber mat is 3mm, the thickness of the second glass fiber mat is 3mm, and the thickness of the ceramic fiber mat is 6mm.

[0119] Comparative Example 1

[0120] This comparative example provides an aerogel composite material.

[0121] The difference between this comparative example and Example 1 is that:

[0122] Using only a 2mm thick first glass fiber mat and a 2mm thick second glass fiber aerogel mat, the glass fiber mat was subjected to the same impregnation, gelation and aging treatments and drying treatments as in Example 1 to obtain an aerogel composite material.

[0123] Comparative Example 2

[0124] This comparative example provides an aerogel composite material.

[0125] The difference between this comparative example and Example 1 is that:

[0126] Using only 4mm thick ceramic fiber felt, the ceramic fiber felt was subjected to the same impregnation, gelation and aging treatment and drying treatment as in Example 1 to obtain an aerogel composite material.

[0127] Comparative Example 3

[0128] This comparative example provides an aerogel composite material.

[0129] The difference between this comparative example and Example 1 is that:

[0130] The thickness of the first glass fiber mat is 0.5 mm, the thickness of the second glass fiber mat is 0.5 mm, and the thickness of the ceramic fiber mat is 3 mm.

[0131] Comparative Example 4

[0132] This comparative example provides an aerogel composite material.

[0133] The difference between this comparative example and Example 1 is that:

[0134] The thickness of the first glass fiber mat is 1.3 mm, the thickness of the second glass fiber mat is 1.3 mm, and the thickness of the ceramic fiber mat is 1.4 mm.

[0135] Comparative Example 5

[0136] This comparative example provides an aerogel composite material.

[0137] The difference between this comparative example and Example 1 is that:

[0138] The thickness of the first glass fiber mat is 1.5 mm, the thickness of the second glass fiber mat is 1.5 mm, and the thickness of the ceramic fiber mat is 1 mm.

[0139] Test case

[0140] The interlaminar shear strength, density, thermal conductivity at 25°C, and appearance of the aerogel composites in the examples and comparative examples after the tests were evaluated. The test results are shown in Table 1.

[0141] Interlaminar shear strength: tested according to GB / T32382-2015;

[0142] Thermal insulation capability: 675℃±15℃, single-sided heating for 5 minutes under 0.9MPa pressure, then depressurized to 0.03MPa, and the cold surface temperature (including heating time) was recorded after 20 minutes.

[0143] Table 1 Test data for the examples and comparative examples

[0144]

[0145] According to the data in Table 1, and through comparative examples 1 and 2, it can be seen that by adopting a specific three-layer sandwich structure and combining it with an integrated impregnation and gelation process, the advantages of both can be fully utilized through the mechanical encapsulation of glass fiber and the support of the intermediate ceramic fiber. Meanwhile, Comparative Example 1, which only uses glass fiber mat, has high interlaminar shear strength but significantly insufficient thermal insulation; Comparative Example 2, which only uses ceramic fiber mat, has excellent thermal insulation performance but extremely poor mechanical structural integrity, resulting in chipped edges and corners, which significantly limits its practical application.

[0146] Comparative Examples 1, 6, 7 and Comparative Examples 3-5 show that controlling the thickness of the glass fiber mat and ceramic fiber mat at a specific ratio is crucial for achieving a balance between mechanical and thermal insulation performance. When the outer glass fiber mat thickness is too low (Comparative Example 3), the protection of the brittle ceramic fiber mat is insufficient, resulting in slight warping and folding of the composite material. When the glass fiber mat is relatively too thick or the ceramic fiber mat is relatively too thin (Comparative Examples 4-5), the thermal insulation foundation provided by the ceramic fiber mat is weakened, and the back temperature increases significantly from 150.2℃ to 175.4℃ and 178.9℃, respectively, leading to severe deterioration of thermal insulation performance. Furthermore, when the overall thickness is too large, the interlayer bonding strength decreases significantly. Due to limitations in the penetration and strength of the gel network, maintaining the thickness within an optimal range is essential to balance interlayer bonding strength and thermal insulation effect.

[0147] As can be seen from the comparison of Example 1 and Example 2, supercritical drying and other specific drying methods can better maintain the nanoporous network structure of aerogel compared with atmospheric pressure drying, resulting in composite materials with lower density, lower thermal conductivity and higher interlaminar shear strength.

[0148] As can be seen from the comparison of Examples 1 and 3-5, parameters such as the ratio of precursor to water in the sol formulation will affect the performance of the resulting continuous gel network. By precisely controlling the sol formulation, the interfacial bonding strength and thermal insulation effect of aerogel composite materials can be further improved.

[0149] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0150] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing an aerogel composite material, characterized in that, Includes the following steps: A first composite structure is obtained by sequentially stacking a first glass fiber mat, a ceramic fiber mat, and a second glass fiber mat, wherein the thickness ratio of the first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat is 1:(1.5~3):(0.5~2). The first composite structure was immersed in an aerogel precursor sol for impregnation treatment to obtain the second composite structure. The second composite structure was subjected to gelation reaction and aging treatment in sequence to obtain the third composite structure; The third composite structure is dried to obtain the aerogel composite material.

2. The method for preparing the aerogel composite material according to claim 1, characterized in that, The thickness of the first glass fiber mat is 0.5 mm to 3 mm; and / or The thickness of the second fiberglass mat is 0.5mm to 3mm; and / or The thickness of the ceramic fiber felt is 1mm to 5mm; and / or The thickness of the first composite structure is 2mm to 9mm.

3. The method for preparing the aerogel composite material according to claim 1, characterized in that, The areal density of the first glass fiber mat is 100 g / m³. 2 ~300g / m 2 ; and / or The areal density of the second glass fiber mat is 100 g / m³. 2 ~300g / m 2 ; and / or The areal density of the ceramic fiber felt is 150 g / m³. 2 ~400g / m 2 .

4. The method for preparing the aerogel composite material according to any one of claims 1 to 3, characterized in that, The gelation reaction and aging treatment steps include: The second composite structure was left to stand at 40℃~60℃ for 2h~12h, and then aged in an aging solution at 50℃~70℃ for 12h~24h, wherein the aging solution included ethanol.

5. The method for preparing the aerogel composite material according to any one of claims 1 to 3, characterized in that, The first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all wet-laid fiber mats; and / or The first glass fiber mat, the ceramic fiber mat, and the second glass fiber mat are all pretreated, and the pretreatment steps include baking at 300℃~500℃ for 1h~2h.

6. The method for preparing the aerogel composite material according to any one of claims 1 to 3, characterized in that, The aerogel precursor sol includes silica sol, and the preparation method of the silica sol includes: Tetraethyl orthosilicate, ethanol, water, and hydrochloric acid are mixed in a molar ratio of 1:(6~10):(3~5):(0.0005~0.002) and hydrolyzed to form a prepolymer solution; The pH of the prepolymer solution is adjusted to 7-8, and the silica sol is formed by condensation polymerization.

7. The method for preparing the aerogel composite material according to any one of claims 1 to 3, characterized in that, The drying process employs supercritical drying, and the supercritical drying steps include: The third composite structure was wrapped with a mesh cloth, and ethanol was injected into a high-pressure reactor. The reactor was then kept at 240℃~260℃ and 6MPa~8MPa for 2h~4h.

8. The method for preparing the aerogel composite material according to claim 7, characterized in that, The mesh size of the mesh fabric is 0.5mm to 2mm.

9. An aerogel composite material, characterized in that, The aerogel composite material was prepared using the preparation method described in any one of claims 1 to 8.

10. An aerogel composite material prepared by the preparation method of any one of claims 1 to 8, or the aerogel composite material of claim 9, is used in the field of battery thermal insulation.

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