Heat insulation type battery insulation spacer and production process thereof

Abstract

The invention relates to the technical field of batteries, and discloses a heat insulation type battery insulation spacer and a production process thereof, the insulation spacer comprises the following components by mass: 30-70 parts of high temperature curing resin; 0.5-5 parts of a foaming agent; 5 to 30 parts of a ceramic precursor; 1-15 parts of a gradient structure inducer; 3 to 20 parts of a fire enhancing component; 2-11 parts of an additive; the production process comprises the following steps: firstly, mixing high-temperature curing resin, a foaming agent, a ceramic precursor, a gradient structure inducer, a fire enhancing component and an additive to prepare a premix; then, carrying out hot press molding on the premix, and forming a density gradient structure by using a gradient structure inducer; and finally, carrying out high-temperature curing on the molded product to obtain the product. The heat insulation type battery insulation spacer can quickly form a compact carbon layer at high temperature, inhibit flame spreading, keep the structure stable and remarkably improve the flame retardance and heat insulation performance of a battery system.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, in particular to a heat-insulating battery insulating gasket and a production process thereof. Background Art

[0002] With the development of the new energy and energy storage industries, chemical batteries are widely used. However, batteries are prone to thermal runaway under abusive conditions such as overcharging and short-circuiting, instantly releasing large amounts of heat. If not effectively suppressed, this can trigger a chain reaction that can cause the entire battery pack to combust and explode. Therefore, deploying efficient thermal insulation and flame-retardant components to prevent the spread of thermal runaway is crucial to improving battery system safety.

[0003] To improve battery safety, existing technologies primarily use inherently flame-retardant polymers as substrates or add phosphorus- and nitrogen-based flame retardants and inorganic fillers to general-purpose materials. Multi-layer composite structures or surface thermal insulation coatings are also common approaches. These methods aim to slow flames and heat transfer, thereby buying time for emergency response.

[0004] However, existing technologies still have shortcomings. The char layers formed by many materials at high temperatures are of poor quality, with a loose and unstable structure, making them incapable of providing long-term insulation. Some substrates soften and deform at high temperatures, even melting and dripping, losing their protective properties and posing a risk of secondary combustion. Furthermore, traditional preparation methods struggle to achieve microscopic synergy between the various components, limiting their overall protective performance.

[0005] Therefore, the present invention provides a heat-insulating battery insulating gasket and a production process thereof to solve the deficiencies of the prior art. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a heat-insulating battery insulating gasket and a production process thereof, which solves the problems of poor carbon layer quality and poor structural stability of the prior battery insulating gasket at high temperatures.

[0007] To achieve the above objectives, the present invention is implemented through the following technical scheme: a heat-insulating battery insulating gasket, comprising the following components in parts by mass: high-temperature curing resin: 30-70 parts; foaming agent: 0.5-5 parts; ceramic precursor: 5-30 parts; gradient structure inducer: 1-15 parts; fire-enhancing component: 3-20 parts; additive: 2-11 parts.

[0008] A high-temperature curing resin (30-70 parts) serves as the base continuous phase, providing the necessary mechanical support and overall shape for the entire gasket. The present invention uses a high-temperature curing resin with excellent thermal stability to ensure that the gasket maintains its structural integrity and critical insulation properties at the battery's normal operating temperature and even higher.

[0009] The introduction of a foaming agent (0.5-5 parts) is crucial for achieving lightweight materials and efficient thermal insulation. During the gasket preparation process, the foaming agent decomposes or reacts under specific conditions to produce gas, forming a large number of fine, closed, or semi-closed pores in the resin matrix. These evenly distributed pores significantly reduce the overall thermal conductivity of the material, effectively blocking heat transfer between battery cells by extending the heat transfer path, reducing solid-phase heat conduction, and inhibiting air convection.

[0010] The use of ceramic precursors (5-30 parts) is a key innovation in this invention, enhancing the material's high-temperature resistance and fire safety. Under high temperatures (such as when a battery experiences thermal runaway or an external fire source), these precursors can be in situ converted into a ceramic phase with high thermal stability and excellent insulation properties. This resulting ceramic phase forms a solid physical barrier, effectively preventing flame spread and high-temperature erosion. It also maintains the material's structural stability under extreme conditions, preventing chain reactions caused by gasket failure.

[0011] One of the most distinctive innovations of this invention lies in the use of a gradient structure inducer (1-15 parts). This component's core function is to regulate the distribution of components or pore structure within different regions of the material during the gasket preparation process, thereby forming a non-uniform structure with a density or porosity gradient along a specific direction. This allows the gasket to exhibit customized functional properties at different levels. For example, the side closest to the heat source may have higher porosity to maximize thermal insulation, while the other side may have higher density to provide better mechanical support or interfacial bonding.

[0012] The addition of a fire-enhancing component (3-20 parts) provides the gasket with active safety protection. These components remain stable under normal operating conditions, but upon exposure to flame or reaching a specific trigger temperature, they rapidly undergo chemical or physical changes, such as expansion and carbonization to form a dense char layer, or release of non-flammable gases to dilute the oxygen concentration.

[0013] Finally, although additives (2-11 parts) are auxiliary components, their selection and proportion play an indispensable role in optimizing material processing performance, improving long-term stability, and ensuring effective synergy among core functional components.

[0014] Preferably, the foaming agent is melamine or azodicarbonamide; The additives include an antioxidant and a lubricant, wherein the antioxidant is a hindered phenol antioxidant and the lubricant is a metal stearate; The high-temperature curing resin includes a blend of methylphenyl vinyl silicone resin and boron-modified phenolic resin, and the mass ratio of the methylphenyl vinyl silicone resin to the boron-modified phenolic resin is 2:3-3:2.

[0015] The present invention adopts a blend of methylphenyl vinyl silicone resin and boron-modified phenolic resin as the core resin system, and the purpose is to carry out a precise ratio design for the synergistic effect of the two. Controlling the mass ratio of the two resins in the range of 2:3 to 3:2 is the key to achieving this synergistic effect. This ratio ensures that at high temperatures, there is a sufficient amount of silicone resin in the system to pyrolyze to form a stable silica ceramic skeleton, and there is sufficient boron-modified phenolic resin to provide a high residual carbon content and boron element as a flux, forming a low-melting-point borosilicate glass phase in situ. This glass phase can fill and heal the microcracks in the carbon layer, fusing the independent carbon skeletons into a dense, stable ceramic thermal insulation barrier with self-healing properties.

[0016] On this basis, the introduction of a blowing agent (such as melamine or azodicarbonamide) releases non-flammable gases during the curing process, creating a uniform porous structure within the matrix. This is the foundation for achieving low thermal conductivity. The decomposition of the blowing agent also contributes to the formation of an expanded char layer. Furthermore, the synergistic effect of additives such as hindered phenolic antioxidants and metal stearate lubricants ensures uniform dispersion and thermal stability of all components during processing, guaranteeing the uniform construction of the aforementioned functional structure.

[0017] Preferably, the ceramic precursor comprises tetraethoxysilane and nano-sized silicon dioxide; The mass ratio of the tetraethoxysilane to the nano-scale silicon dioxide is 7:3-6:1.

[0018] The liquid ceramic-forming silicon source (tetraethoxysilane) is organically combined with a solid nanofiller (nanoscale silica). In this system, tetraethoxysilane acts as a precursor, and in subsequent processes, through hydrolysis and condensation reactions, a continuous silica network is generated in situ, acting as both a binder and a matrix.

[0019] The key to achieving this structure is to precisely control the mass ratio of the two within the range of 7:3 to 6:1. This ratio ensures that the system contains sufficient tetraethoxysilane to form a complete and continuous ceramic matrix, thereby firmly encapsulating and bonding the pre-added nano-sized silica particles. At the same time, the nano-silica acts as a nucleation skeleton, not only providing a core for the growth of the ceramic phase, but also effectively enhancing the structural strength and dimensional stability of the final ceramic layer.

[0020] Preferably, the gradient structure inducing agent comprises polydimethylsiloxane grafted with acrylate and polypropylene microspheres grafted with maleic anhydride; The acrylate grafted modified polydimethylsiloxane is obtained by grafting vinyl-terminated polydimethylsiloxane with methyl methacrylate under the action of an initiator, wherein the initiator is benzoyl peroxide or azobisisobutyronitrile; The maleic anhydride grafted polypropylene microspheres are prepared by melt grafting polypropylene microspheres with maleic anhydride, wherein dicumyl peroxide or benzoyl peroxide is used as an initiator. The particle size of the maleic anhydride grafted polypropylene microspheres is 10-50 μm. The mass ratio of the acrylate grafted modified polydimethylsiloxane to the maleic anhydride grafted modified polypropylene microspheres is 3:2-4:1.

[0021] The gradient structure inducer is a blend of acrylate-grafted polydimethylsiloxane and maleic anhydride-grafted polypropylene microspheres. Its design leverages the different behavioral properties of these two components within the main resin to create a functional gradient structure within the product.

[0022] The modified siloxane acts as a migrating component. The low surface energy of its polydimethylsiloxane backbone causes it to spontaneously accumulate on the material surface and at the interfaces of internal pores during the curing process. In contrast, maleic anhydride-modified polypropylene microspheres (10-50µm in diameter) serve as anchor components. Their surface polar functional groups effectively bond with the main resin matrix, allowing for stable dispersion within the bulk of the material.

[0023] Key to achieving this structure is maintaining a modified silicone to modified polypropylene mass ratio of 3:2 to 4:1. This ratio ensures sufficient modified silicone migrates to the surface to form a silicon-rich layer, while the polypropylene microspheres, acting as anchors, remain stably distributed in the bulk. This controlled and uneven distribution of components creates a functional gradient from the surface to the interior of the material, achieving differentiated internal and external functionality.

[0024] Preferably, the fire-enhancing component comprises ammonium polyphosphate and pentaerythritol; The degree of polymerization of the ammonium polyphosphate is 1000-3000, and the particle size of the pentaerythritol is 10-70 μm; The mass ratio of the ammonium polyphosphate to pentaerythritol is 2:1-4:1.

[0025] The fire-strengthening component, composed of ammonium polyphosphate and pentaerythritol, creates an in-situ physical barrier during fire through a classic acid-carbon source synergistic effect. The core of this design lies in the precise control of the component properties and ratios.

[0026] Ammonium polyphosphate (AMP) with a degree of polymerization (DP) of 1000-3000 is used as the acid source. Its long-chain structure ensures thermal stability during material processing, yet it efficiently decomposes at flame temperatures, releasing polyphosphoric acid, a strong dehydration catalyst. This acid then reacts with pentaerythritol (PEP), the carbon source. The particle size of PEP is controlled between 10 and 70 µm to ensure uniform dispersion within the resin matrix, paving the way for a consistent and complete carbonization reaction.

[0027] The mass ratio of ammonium polyphosphate to pentaerythritol is controlled within a range of 2:1 to 4:1 to optimize the stoichiometric ratio of acid source to carbon source. This ratio ensures sufficient phosphoric acid to catalyze the complete dehydration of pentaerythritol to char. This, combined with the non-flammable gases released during the decomposition of ammonium polyphosphate, creates a dense and porous expanded carbon layer. This carbon layer acts as a physical barrier, effectively isolating the product from heat and oxygen.

[0028] The present invention also provides a production process for a heat-insulating battery insulating gasket, comprising the following steps: S1. Mixing a high-temperature curing resin, a foaming agent, a ceramic precursor, a gradient structure inducing agent, a fire-enhancing component, and an additive according to a proportion to obtain a premix; S2, placing the premix in a mold for hot pressing to form a molded product with a density gradient structure through the action of a gradient structure inducer; S3. Curing the molded product with the density gradient structure at high temperature to obtain a heat-insulating battery insulating gasket.

[0029] In step S1, all predetermined components—high-temperature curing resin, foaming agent, ceramic precursor, gradient structure inducing agent, fire-strengthening component, and necessary additives—are mixed in precise proportions to form a uniform premix. The key to this step is ensuring that all powdered, liquid, or microspherical components are fully dispersed within the resin matrix, forming a macroscopically uniform and microscopically functional mixed system.

[0030] For step S2, the prepared premix is placed in a specially designed mold for hot pressing. At this critical stage, a structure with a density gradient is formed inside the molded object through the unique effect of the gradient structure inducer. The hot pressing process is not only a means of giving the material a predetermined shape, but more importantly, under specific temperature and pressure conditions, the gradient structure inducer is activated. This involves the selective migration of the inducer component in the resin melt, different interactions with the resin matrix, or initiation of local reactions in specific areas, which leads to differences in the density or pore distribution in different areas inside the material, i.e., the formation of a density gradient.

[0031] In step S3, the molded product with a density gradient structure is subjected to high-temperature curing treatment to finally obtain a finished thermal insulation battery insulation gasket. This final heat treatment step is crucial, as its purpose is to completely cross-link and cure the high-temperature curing resin to form a stable and strong three-dimensional network structure. This process not only gives the gasket its ultimate mechanical strength, heat resistance, and electrical insulation properties, but also ensures that the gradient structure formed in step S2 is permanently "locked" inside the material and will not be easily changed due to subsequent use or environmental changes.

[0032] Preferably, the step S1 comprises: dry-mixing a foaming agent, a ceramic precursor, a gradient structure inducing agent, a fire-enhancing component and an additive to obtain a solid mixture; adding the solid mixture to a high-temperature curing resin, and stirring until the components are evenly dispersed to obtain the premix.

[0033] The key is the adoption of a two-step homogenization strategy of "solid-solid mixing first, followed by solid-liquid dispersion." This step begins with dry premixing of all solid powders, including the foaming agent, ceramic precursor, gradient structure inducing agent, fire-enhancing component, and additives. This premixing step ensures that these functionally diverse powders are evenly distributed at the microscopic level before being added to the high-viscosity resin system. This approach effectively avoids agglomeration or uneven dispersion that could occur during subsequent liquid mixing due to differences in wettability or density among the components.

[0034] Finally, this homogenized solid mixture is added to the high-temperature curing resin and stirred to ensure a stable and consistent dispersion of all functional components within the liquid matrix. This step is the key process foundation for the reliable realization of subsequent synergistic effects (such as uniform foaming, gradient formation, and overall porcelain formation).

[0035] Preferably, the step S2 comprises: evenly spreading the premix in the mold cavity, closing the mold, and hot pressing the mold at a pressure of 5-15 MPa; The hot pressing process adopts staged heating: the mold temperature is raised to 60-80°C and kept warm for 5-15 minutes, and then further raised to 100-140°C and kept warm for 10-20 minutes to obtain a molded product with a density gradient structure.

[0036] A segmented heating hot pressing process is adopted, and the density gradient structure inside the material is actively constructed through precise control of temperature and time.

[0037] The first stage, held at a relatively low temperature of 60-80°C, primarily reduces the viscosity of the premix system, ensuring good fluidity. This critical window provides the necessary time and conditions for the migration of the gradient structure-inducing agent: the low-surface-energy modified siloxane component spontaneously accumulates on the mold surface during this phase, initially establishing a gradient in chemical composition. This is before the resin has fully solidified.

[0038] Subsequently, the temperature is raised to 100-140°C to enter the second stage. This stage triggers two key reactions simultaneously: the foaming agent decomposes due to heat, generating a large number of pores inside the material; at the same time, the high temperature also causes the resin matrix to rapidly cross-link and solidify. This "gradient construction first, foaming and solidification later" strategy "locks" the chemical gradient formed in the first stage into the final product. Due to the differences in components in different regions, the foaming behavior and pore structure show non-uniformity in the thickness direction of the material, ultimately forming the desired density gradient structure. The 5-15MPa pressure throughout the process ensures that the product is compactly molded and controls the overall morphology.

[0039] Preferably, step S3 includes: placing the molded object of the density gradient structure in a curing device, heating it to 180-220°C in a nitrogen atmosphere with a purity of 99.5%-99.99% and maintaining the temperature for 1-3 hours, and then cooling it at a cooling rate of 1-10°C / minute for 30-120 minutes to obtain a thermally insulating battery insulating gasket.

[0040] The first step is to achieve complete cross-linking. The molded product is placed in a nitrogen atmosphere with a purity of 99.5%-99.99% and heated to 180-220°C for 1-3 hours. The high-purity nitrogen provides inert protection, preventing oxidative degradation of the material at high temperatures. This temperature range and holding time are designed to ensure complete cross-linking of the resin system, forming a stable three-dimensional network structure, which is the foundation for the product's ultimate thermal stability and mechanical properties.

[0041] The subsequent cooling stage is equally critical. By controlling the cooling rate to 1-10°C / minute and completing the cooling within 30-120 minutes, the thermal stress within the material is systematically released. This gentle cooling process effectively avoids product warping or microcracking caused by sudden temperature changes, ensuring the final gasket's excellent dimensional stability and structural integrity.

[0042] The present invention provides a heat-insulating battery insulating gasket and its production process. It has the following beneficial effects: 1. This invention introduces a fire-resistant component into the thermally insulating battery gasket, enabling it to rapidly respond to extreme high-temperature conditions, such as thermal runaway, and induce the formation of a continuous, dense carbon barrier on the material's surface. This carbon layer not only effectively inhibits flame spread and improves the gasket's thermal stability, but also provides critical thermal protection for the battery pack, enhancing overall flame retardancy and safety.

[0043] 2. This invention utilizes a gradient structure inducer during the preparation of thermally insulating battery gaskets to finely control the spatial distribution of the carbonized region during pyrolysis, fostering the formation of a directional, layered microstructure. This structural optimization effectively improves the uniformity and thermal barrier continuity of the carbon layer, supporting the formation of a stable thermal shielding path for the gasket at high temperatures and enhancing its synergistic protective effectiveness as a thermal barrier between cells.

[0044] 3. This invention introduces a ceramic precursor into the insulating battery gasket, forming an inorganic rigid skeleton in situ after pyrolysis of the material, significantly enhancing the mechanical strength of the carbon layer and its structural stability at high temperatures. This inorganic-organic synergistically reinforced gasket can better maintain its shape and thermal insulation function even under severe thermal shock conditions, reducing the risk of thermal runaway diffusion caused by material failure and improving the thermal integrity of the battery system.

[0045] 4. This invention utilizes a multi-stage temperature control strategy in the production process of thermally insulating battery gaskets, achieving temporal coordination and optimization of the reactivity of various functional components (such as the fire-enhancing component, gradient structure inducer, and ceramic precursor) during the material curing process. This process path helps ensure a dense and uniform internal structure of the gasket and maximizes the synergistic effects of the various components, thereby ensuring the stable performance of the thermally insulating gasket's excellent flame retardant and thermal insulation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] Please see the attached Figure 1 .

[0049] In order to better understand the present invention, the above method is described in detail below with reference to specific embodiments.

[0050] The sources and specifications of the main raw materials and reagents used in the following examples and comparative examples are as follows: The methylphenyl vinyl silicone resin in the high temperature curing resin is IOTA208 from Anhui Aiyota Silicone Oil Co., Ltd., and the boron modified phenolic resin is from Jining Tangyi Chemical Co., Ltd., with the brand Tangyi product. The melamine in the foaming agent is produced by Guangzhou Bobang Chemical Co., Ltd. under the brand of Sichuan Golden Elephant / Yuxiang, and the azodicarbonamide foaming agent is produced by Jinan Yeqing Biotechnology Co., Ltd. under the brand of Yeqing. The hindered phenol antioxidant in the additives is antioxidant 1010 from Dongguan Xingyuan Chemical Co., Ltd., and the lubricant metal stearate is Lubao 1801 stearic acid from Guangzhou Taili Chemical Co., Ltd. The tetraethoxysilane in the ceramic precursor is D-130 from Hangzhou Jessica Chemical Co., Ltd., and the nano-silicon dioxide is TH-6380 from Shandong Wanhua Tianhe New Materials Co., Ltd. The ammonium polyphosphate in the fire-intensifying component was from Shandong Benniu Chemical Co., Ltd., brand Benniu Chemical, and pentaerythritol was from Handan Congtai District Xinyuansheng Chemical Co., Ltd., CAS: 61788-97-4. Preparation Example 1: Preparation method of gradient structure inducer Preparation of acrylate grafted polydimethylsiloxane: Ingredients: Main polymer: vinyl-terminated polydimethylsiloxane, CAS: 68083-19-2; graft monomer: methyl methacrylate, CAS 80-62-6; initiator: azobisisobutyronitrile, CAS: 78-67-1; benzoyl peroxide, CAS: 94-36-0; reaction solvent: formyl, CAS: 108-88-3.

[0051] Raw material formula (parts by mass): vinyl-terminated polydimethylsiloxane: 100 parts; methyl methacrylate: 20-40 parts; azobisisobutyronitrile or benzoyl peroxide (initiator): 0.5-2 parts; toluene (reaction solvent): 200-420 parts.

[0052] Preparation steps: Adding and Dissolving: In a clean, dry reactor equipped with a mechanical stirrer, reflux condenser, and nitrogen blanketing system, add 100 parts vinyl-terminated polydimethylsiloxane and 200-400 parts toluene. Stir and allow to fully dissolve at room temperature to form a homogeneous, clear solution.

[0053] Addition and deoxygenation: Add 20-40 parts of methyl methacrylate to the above solution and stir until uniform. Then, introduce nitrogen into the reactor and bubble it for 20-30 minutes to completely remove oxygen from the system and provide an inert environment for subsequent reactions.

[0054] Heating and initiation: After deoxygenation is completed, the reactor is heated to the specified temperature.

[0055] If using azobisisobutyronitrile: control the reaction temperature at 70-85°C.

[0056] If using benzoyl peroxide: control the reaction temperature at 80-95°C.

[0057] Dissolve 0.5-2 parts of the selected initiator in a small amount of toluene (5-20 parts) in advance, and then add the initiator solution to the reactor at a uniform rate over 15-30 minutes through a dripping device.

[0058] Graft polymerization: Keep the material in a steady stirring state at a constant temperature of 70-85°C and under nitrogen protection, and continue the reaction for 5-10 hours to ensure that the grafting reaction is fully carried out.

[0059] Product Purification: After the reaction is complete, stop heating and cool the system to room temperature. Slowly add the viscous product solution in the reactor to 8-10 volumes of methanol (as a precipitant) while stirring. The target product will precipitate as a white solid, while the unreacted starting material remains in the solvent.

[0060] Collection and Drying: Collect the precipitated solid product by filtration and rinse the filter cake 2-3 times with a small amount of precipitant. Finally, place the resulting product in a vacuum oven at 50-70°C and dry it for 12-24 hours until constant weight is achieved.

[0061] The white solid finally obtained is the target product "acrylate grafted modified polydimethylsiloxane".

[0062] Preparation of maleic anhydride grafted polypropylene microspheres: Ingredients: Main polymer: polypropylene, CAS: 9003-07-0; graft monomer: maleic anhydride, CAS: 108-31-6; initiator: dicumyl peroxide (DCP) CAS: 80-43-3; benzoyl peroxide, CAS: 94-36-0.

[0063] Raw material formula (parts by mass): polypropylene: 100 parts; maleic anhydride: 1-5 parts; initiator (DCP or BPO): 0.2-1 part.

[0064] Preparation steps: Premixing: Pre-dry 100 parts of polypropylene at 80-90°C for 2-4 hours. Place the dried polypropylene, 1-5 parts of maleic anhydride, and 0.2-1 part of the selected initiator (DCP or BPO) into a high-speed mixer and dry blend at room temperature for 5-10 minutes to ensure uniform mixing of the components.

[0065] When using dicumyl peroxide (DCP), the temperature profile can be set from the feed section to the head section: 170°C → 190°C → 210°C → 200°C.

[0066] When using benzoyl peroxide (BPO), the temperature profile can be set from the feed section to the die head section: 160°C → 180°C → 190°C → 185°C.

[0067] Cooling and granulation: The high-temperature grafted modified polymer melt is extruded from the die head into strips and immediately enters a water tank for cooling and shaping, and then is cut into uniform particles with a length of 2-4 mm by a pelletizer.

[0068] Purification treatment: The cut granular product is heated in a vacuum oven at 110-120°C for 6-10 hours.

[0069] Micronization and Sieving: The purified, dried granules are fed into a cryogenic mill and ground under liquid nitrogen to prevent the polymer from heating and melting during the pulverization process. The pulverized material is then graded using an air sieving screen or a standard vibrating screen to collect a powder with a particle size of 10-50µm.

[0070] The final white or slightly yellow microsphere powder is the target product "maleic anhydride grafted modified polypropylene microspheres" Melt grafting reaction: The premixed materials are fed steadily into a twin-screw extruder via a metering feeder. The screw speed is set between 150-300 rpm. Depending on the selected initiator, the extruder temperature profile must be adapted to its characteristics, but the overall temperature range is generally between 170°C and 220°C.

[0071] When using dicumyl peroxide (DCP), its higher decomposition temperature is well matched to the processing temperature of PP, making it a more commonly used initiator in this process. A typical temperature profile from the feed section to the die head section can be set as: 170°C → 190°C → 210°C → 200°C.

[0072] When using benzoyl peroxide (BPO), the temperature profile can be set from the feed section to the die head section: 160°C → 180°C → 190°C → 185°C.

[0073] Cooling and granulation: The high-temperature grafted modified polymer melt is extruded from the die head into strips and immediately enters a water tank for cooling and shaping, and then is cut into uniform particles with a length of 2-4 mm by a pelletizer.

[0074] Purification: The granular product is heated in a vacuum oven at 110-120°C for 6-10 hours. The purpose of this step is to sublime the unreacted, volatile maleic anhydride monomer, thereby achieving the purpose of purification.

[0075] Micronization and Sieving: The purified, dried granules are fed into a cryogenic mill and ground under liquid nitrogen to prevent the polymer from heating and melting during the pulverization process. The pulverized material is then graded using an air sieving screen or a standard vibrating screen to collect a powder with a particle size of 10-50µm.

[0076] The white or slightly yellow microsphere powder finally obtained is the target product "maleic anhydride grafted modified polypropylene microspheres".

[0077] Preparation of gradient structure-inducing agent: Preparation steps: Weighing: According to the formula (the mass ratio of acrylate-grafted polydimethylsiloxane to maleic anhydride-grafted polypropylene microspheres is 3:2-4:1).

[0078] Blending: Put the two weighed materials into a V-type mixer or a three-dimensional motion mixer.

[0079] Homogenization: Mix at 50-100 rpm for 20-40 minutes at room temperature.

[0080] Packaging: Take out the uniformly mixed powder (the final uniformly mixed powder is the target product "gradient structure inducer"), seal it and set aside for use.

[0081] Example 1:

[0082] S1. Preparation of premix (parts by mass): foaming agent (melamine): 2.5 parts; ceramic precursor (a mixture of tetraethoxysilane and nano-sized silica, with a mass ratio of 4:1): 17.5 parts; gradient structure inducer (a mixture of polydimethylsiloxane grafted with acrylate and polypropylene microspheres grafted with maleic anhydride, with a mass ratio of 2.75:1): 8 parts; fire-resistant component (ammonium polyphosphate and pentaerythritol, with a degree of polymerization of 20% ammonium polyphosphate). 00, the pentaerythritol used has a particle size of 40µm and the mass ratio of the two is 3:1): 11.5 parts; additives (hindered phenolic antioxidant and metal stearate of lubricant): 6.5 parts; the above precisely weighed solid components are placed together in a V-type high-efficiency mixer. At an ambient temperature of approximately 25°C, set the mixer speed at 30 rpm and dry mix for 15 minutes to ensure that all solid powder components are evenly mixed to obtain a solid mixture. High-temperature curing resin (a blend of methylphenyl vinyl silicone resin and boron-modified phenolic resin, mass ratio of 1:1): 50 parts; the high-temperature curing resin is added to a stainless steel reactor equipped with a temperature-controlled jacket and stirring device. The jacket is preheated and the resin temperature is controlled at 40°C. While the reactor is continuously stirred by an anchor-type stirring paddle at 100 rpm, the solid mixture is slowly and batchwise added to the high-temperature curing resin in the reactor through the feed port. After all the solid mixtures were added, the temperature was maintained at 40°C and the stirring rate was 100 rpm for 60 minutes to ensure that all the solid components were fully and evenly dispersed in the resin matrix without obvious particle agglomeration, and finally a premix was obtained.

[0083] S2. Hot Pressing: The premix prepared in step S1 is evenly spread on the pre-cleaned and release-coated surface by scraping or pouring. The mold is carefully closed and the loaded mold is moved to the center of the heated work surface of the flat vulcanizer (hot press). A pressure of 10 MPa is applied to the mold. The program temperature control system of the hot press is started and the temperature is raised in a stepwise manner: In the first stage, the mold temperature is raised from the current 50°C to 70°C at a rate of 5°C / min. The timer starts when the temperature reaches 70°C. And maintain the temperature at this temperature for 10 minutes; second stage: after the first stage of insulation is completed, continue to increase the mold temperature from 70℃ to 120℃ at a heating rate of 5℃ / minute, start timing after reaching 120℃, and maintain the temperature at this temperature for 15 minutes; after the second stage of insulation is completed, while maintaining a pressure of 10MPa, stop heating, and start cooling through the mold cooling system (such as passing cooling water). After the mold temperature drops to about 60℃, slowly release the pressure, open the mold and take out the molded object with a preliminary density gradient structure.

[0084] S3. High-temperature curing: The molded article with a density gradient structure obtained in step S2 is completely removed from the mold and carefully placed on a high-temperature-resistant sample holder inside a programmable temperature-controlled atmosphere oven (curing equipment). Close the oven door and introduce 99.9% pure nitrogen gas into the oven chamber through the atmosphere control system. Set the gas flow rate to 2 liters / minute and continue ventilation for 15 minutes to displace the air inside the oven, ensuring a stable inert protective atmosphere. Activate the oven's programmed temperature ramp function and set a ramp rate of 5°C / minute to linearly increase the oven temperature from the current room temperature (or preheat temperature) to 200°C. Once the oven temperature reaches and stabilizes at 200°C, begin the timer and maintain this temperature for precisely 2 hours to allow for sufficient chemical crosslinking and curing. After the 2-hour curing period, stop heating and initiate the programmed cooling function while continuing to introduce 99.9% pure nitrogen gas to provide a protective atmosphere. Set the cooling rate to a strict 5°C / minute. When the furnace temperature naturally cools down to below 60°C, stop introducing nitrogen, open the furnace door, and carefully remove the fully solidified thermal insulation battery gasket. This cooling process takes about 60 minutes in total.

[0085] Example 2:

[0086] S1. Preparation of premix (parts by mass): foaming agent (azodicarbonamide): 5 parts; ceramic precursor (a mixture of tetraethoxysiloxane and nano-sized silica, the mass ratio of the two is 6:1): 30 parts; gradient structure inducer (a mixture of polydimethylsiloxane grafted with acrylate and polypropylene microspheres grafted with maleic anhydride, the mass ratio of the two is 4:1): 15 parts; fire-strengthening component (ammonium polyphosphate and pentaerythritol, the degree of polymerization of the ammonium polyphosphate used is 3000, the particle size of the pentaerythritol used is 70µm, and the particle size of the two is 100µm). The following ingredients are combined: 1) a 4:1 weight ratio of 20 parts of ammonia-based solids (prepared with a 4:1 weight ratio); 2) an additive (a hindered phenolic antioxidant and a metal stearate as a lubricant); 11) each of the precisely weighed solid components are placed in a high-efficiency forced mixer (e.g., a mixer with a high-speed shear function). Dry mixing is performed for 20 minutes at an ambient temperature of approximately 25°C, with the main shaft speed set at 60 rpm and the shear speed at 1500 rpm, to ensure that all solid powder components are thoroughly and evenly mixed to obtain a solid mixture. 70) a high-temperature curing resin (a blend of methylphenyl vinyl silicone resin and boron-modified phenolic resin, in a 3:2 weight ratio) is added to a stainless steel reactor equipped with a precision temperature-controlled jacket and a powerful dispersing and stirring device. The jacket is preheated and the resin temperature is precisely controlled at 50°C. While the reactor is continuously stirred by a high-speed dispersing paddle at 300 rpm, the solid mixture is slowly and evenly added to the high-temperature curing resin in the reactor via a vacuum feeding system. After all the solid mixture is added, the temperature is maintained at 50° C. and the stirring rate is 300 rpm, and the stirring is supplemented by scraping the wall for 90 minutes to form a high-viscosity but uniform premix.

[0087] S2. Hot Pressing: The high-viscosity premix prepared in step S1 is evenly spread or filled into the cavity of a high-strength precision mold (e.g., H13 steel, with a hard chrome-treated cavity surface) that has been thoroughly cleaned, sprayed with a high-performance water-based release agent, and preheated to 60°C by precision coating or high-pressure injection. The mold is carefully closed and the loaded mold is moved to the center of the heated work surface of the servo precision hot press to ensure accurate mold positioning. A pressure of 15 MPa is applied to the mold. The program temperature control system of the hot press is started and the staged heating process is strictly followed: the first stage: the mold temperature is increased from the current 60°C to The temperature is raised to 80°C at a rate of 3°C / min. The timing starts when the temperature reaches 80°C, and the temperature is maintained at this temperature for 15 minutes. The second stage: after the first stage of insulation is completed, the mold temperature is continued to be raised from 80°C to 140°C at a rate of 3°C / min. The timing starts when the temperature reaches 140°C, and the temperature is maintained at this temperature for 20 minutes. After the second stage of insulation is completed, heating is stopped while maintaining a pressure of 15MPa. Forced cooling is started through the precision cooling oil system built into the mold. After the mold temperature drops to about 70°C, the pressure is slowly released, the mold is opened, and the molded object with a preliminary density gradient structure is taken out.

[0088] S3. High-temperature curing: The molded object with a density gradient structure obtained in step S2 is completely removed from the mold and carefully placed on a special high-temperature-resistant ceramic carrier plate inside a high-precision programmable temperature-controlled atmosphere furnace (curing equipment), ensuring that the sample is placed stably. The furnace door is completely sealed, and ultra-pure nitrogen with a purity of up to 99.99% is introduced into the furnace chamber via a high-precision mass flow controller. The gas flow rate is set to 5 liters / minute. The air in the furnace is continuously ventilated for 30 minutes, and the oxygen content in the furnace is monitored in real time to ensure it is below 10 ppm, thus establishing a highly pure, inert protective atmosphere. The oven's programmed temperature ramp function is activated, and the furnace temperature is linearly increased from the current room temperature (or preheat temperature) to 220°C at a precise ramp rate of 3°C / minute. Once the furnace temperature reaches and stabilizes at 220°C (with a temperature fluctuation of less than ±1°C), the timer is started, and the temperature is maintained at 220°C for a precise period of 3 hours to allow for a thorough chemical cross-linking and curing reaction. After the three-hour heat-insulating cure is complete, heating is stopped and, while continuously introducing ultrapure nitrogen (99.99%) to provide a protective atmosphere, the programmed cooling function is initiated. The cooling rate is strictly controlled at 1°C / minute. When the furnace temperature slowly cools below 50°C, the nitrogen flow can be stopped. Once the furnace pressure has reached equilibrium with the external pressure, the furnace door is opened and the fully cured thermal insulation gasket is carefully removed. This cooling process takes approximately 120 minutes in total.

[0089] Example 3:

[0090] S1. Preparation of premix (parts by mass): foaming agent (melamine): 0.5 parts; ceramic precursor (a mixture of tetraethoxysiloxane and nano-sized silica, with a mass ratio of 7:3): 5 parts; gradient structure inducer (a mixture of polydimethylsiloxane grafted with acrylate and polypropylene microspheres grafted with maleic anhydride, with a mass ratio of 3:2): 1 part; fire-resistant component (ammonium polyphosphate and pentaerythritol, the degree of polymerization of the ammonium polyphosphate used is 1000, the particle size of the pentaerythritol used is 10µm, and the mass ratio of the two is 2:1): 3 parts; additive (hindered phenolic antioxidant and metal stearate as a lubricant): 2 parts; put the above-mentioned accurately weighed solid components into a small laboratory mixing container (for example, a plastic bottle with a lid or a mortar), and perform dry mixing by manual shaking or grinding for about 10 minutes. Visually observe to ensure that the solid powder components are basically mixed evenly to obtain a solid mixture. 30 parts of high-temperature curing resin (a blend of methylphenyl vinyl silicone resin and boron-modified phenolic resin in a 2:3 mass ratio). Add the high-temperature curing resin to a glass beaker equipped with a magnetic stirrer and place it on a temperature-controlled magnetic stirrer. Preheat the resin to 30°C in a water bath or on a hot plate. While stirring continuously at approximately 80 rpm, add the solid mixture to the high-temperature curing resin in the beaker in small portions. After all the solid mixture has been added, maintain a temperature of 30°C and a stirring rate of approximately 80 rpm for 45 minutes to ensure that all solid components are well dispersed in the resin matrix and that there is no significant agglomeration of large particles. This will produce a premix.

[0091] S2. Hot pressing: Using a scraper or spatula, spread the premix obtained in step S1 as evenly as possible in a simple mold (e.g., an open aluminum or steel mold frame) that has been pre-cleaned and simply coated with a small amount of release agent (e.g., silicone oil); place a flat plate on top of the mold and move the entire mold between the pressing plates of a manual hydraulic tablet press or a simple hot pressing device; apply a pressure of 5 MPa to the mold; control the mold temperature using the tablet press heating plate or an external heat source, and perform staged heating: first stage: raise the mold temperature from the current room temperature to 60°C as quickly as possible, start the timer after reaching 60°C, and keep it at this temperature for 5 minutes; second stage: after the first stage of insulation is completed, continue to raise the mold temperature to 100°C, start the timer after reaching 100°C, and keep it at this temperature for 10 minutes; after the second stage of insulation is completed, stop heating while maintaining a pressure of 5 MPa, and cool naturally or with air. After the mold temperature drops to about 50°C, slowly release the pressure, open the mold, and remove the molded object with a preliminary density gradient structure.

[0092] S3. High-temperature curing: The shaped article with a density gradient structure obtained in step S2 is completely removed from the mold and carefully placed on a high-temperature-resistant asbestos board or ceramic sheet inside a box-type resistance furnace (curing equipment). Close the furnace door and introduce approximately 99.5% pure industrial nitrogen into the furnace through a simple air inlet pipe. Set the gas flow rate to approximately 1 liter / minute and continue ventilation for approximately 10 minutes to displace the air in the furnace, removing as much oxygen as possible. Start the oven heating and raise the furnace temperature from room temperature to 180°C at a rapid rate (e.g., approximately 8-10°C / minute). Once the furnace temperature reaches and stabilizes at 180°C, start the timer and maintain the temperature at 180°C for one hour to allow the curing reaction to proceed. After the one-hour heat-insulation curing is complete, stop heating. Allow the furnace to cool naturally in the air, or slightly open the furnace door while continuing to introduce a small amount of nitrogen or, after stopping ventilation and sealing the furnace door, accelerate cooling. Try to maintain a cooling rate of approximately 10°C / minute. When the furnace temperature cools down to below 70°C, the furnace door can be opened and the solidified thermal insulation battery insulation gasket can be carefully removed. The total cooling time is about 30 minutes.

[0093] Comparative Example 1: Compared with Example 1, the difference is that: in the preparation of the S1 premix, the gradient structure inducer is not added (that is, the "mixture of acrylate-grafted modified polydimethylsiloxane and maleic anhydride-grafted modified polypropylene microspheres" is not added), and the rest are the same.

[0094] Comparative Example 2: Compared with Example 1, the difference is that in the preparation of the S1 premix, no ceramic precursor is added (ie, no mixture of tetraethoxysilane and nano-sized silicon dioxide is added), and the rest are the same.

[0095] Comparative Example 3: Compared with Example 1, the difference is that in the preparation of the S1 premix, no fire-enhancing component is added (ie, no ammonium polyphosphate and pentaerythritol are added), and the rest are the same.

[0096] Comparative Example 4: Compared with Example 1, the difference is that in the S2 hot pressing molding step, the segmented heating process is changed to: the mold temperature is directly raised from the current 50°C to 120°C at a heating rate of 5°C / minute, the timing is started after reaching 120°C, and the temperature is precisely maintained at this temperature for 25 minutes (that is, the sum of the original two-stage insulation time), and the rest are the same.

[0097] Experiment 1: Experimental Materials: Example 1 sample; Comparative Example 1 sample; Comparative Example 4 sample.

[0098] Experimental equipment: High-precision electronic balance; vernier caliper or high-precision thickness gauge; Archimedean density measuring device (or standard geometry measuring device); sample cutting tools (cutting tool, slicing device).

[0099] Experimental steps: Sample preparation: A standard sheet with a thickness of 10 mm was selected from each group of test samples (Example 1, Comparative Example 1, Comparative Example 4).

[0100] Each sample is evenly cut into three layers along the thickness direction: top layer, middle layer, and bottom layer, with each layer having equal thickness (e.g., about 3.3 mm).

[0101] The complete area of each layer is retained to ensure that the volume calculation is not affected.

[0102] Density test: Measure the mass (q) of each layer of sample using a high-precision balance; measure the volume of each layer of sample (you can use the geometric method: length × width × thickness).

[0103] Calculate the density of each layer: ; Data recording and processing: The density of the three layers of each sample was recorded; the density distribution of each sample in the thickness direction was compared and the gradient degree was analyzed.

[0104] Experimental results (see Table 1) Table 1: Comparison of density distribution in thickness direction of samples (g / cm 3 ) Sample type Top Middle Bottom Example 1 0.34 0.42 0.56 Comparative Example 1 0.47 0.49 0.48 Comparative Example 4 0.4 0.44 0.43 The experimental results demonstrate that the gradient structure inducer introduced into the designed multi-component synergistic system plays a key role in regulating the material's internal structure. Specifically, Example 1 exhibits a significant density gradient across the thickness, while the sample in Comparative Example 1, which does not contain the inducer, exhibits a substantially uniform density distribution. This phenomenon is closely related to the inducer's thermal response during hot pressing, triggering differences in foaming rate or crosslinking degree at different locations, thereby achieving spontaneous evolution of local structural density and confirming its driving role in the formation of the gradient structure.

[0105] Furthermore, the experiments also verified the ability of hot-pressing process parameters to control structure formation. While Comparative Example 4 did not completely eliminate the inducing component, the single-stage heating strategy significantly reduced density variations within the material, demonstrating the influence of temperature control on the inducing agent's mechanism of action. Specifically, the staged heating effectively differentiated the forming rhythm of each structural zone, synchronizing the inducing agent release with the localized reaction. A single thermal field, on the other hand, tends to lead to a uniform structure and inhibit the formation of gradients.

[0106] Comprehensive analysis shows that the formation of the material's internal density gradient structure not only relies on specific structure-inducing components, but also requires a molding process with phased control capabilities. This "component-structure-process" synergistic design concept is the key foundation for achieving high-performance insulating gasket materials.

[0107] Experiment 2: Experimental Materials: Example 1 sample; Comparative Example 1 sample; Comparative Example 2 sample; Comparative Example 4 sample.

[0108] Experimental equipment: Flat-plate thermal conductivity tester; constant temperature test environment (maintain test temperature, e.g., 25°C ± 1°C); calipers, cutting tools, etc. (for sample pretreatment).

[0109] Experimental steps: Sample preparation: Cut specimens of the same size from each group of samples, preferably 100mm×100mm×5mm, to ensure that the sample surface is flat and the thickness is consistent.

[0110] Instrument calibration: Before testing, perform a standard thermal conductivity plate calibration (standard materials such as EPS boards or standard blocks with known thermal conductivity can be used).

[0111] Thermal conductivity measurement: The sample is clamped between the two hot plates of the tester, and the upper and lower plates maintain a stable temperature difference (such as 30℃ and 20℃).

[0112] Based on the steady-state heat transfer principle, the instrument automatically collects heat flux and temperature difference and calculates the thermal conductivity value (unit: W / m·K).

[0113] Each sample was tested at least three times, and the average value was taken as a reference.

[0114] Data recording and organization: The thermal conductivity values measured for all samples were recorded and compared and analyzed.

[0115] Experimental results (see Table 2): Table 2: Comparison of thermal conductivity of each sample Sample type Thermal conductivity 1 Thermal conductivity 2 Thermal conductivity 3 average value Example 1 0.085 0.081 0.083 0.083 Comparative Example 1 0.097 0.093 0.096 0.095 Comparative Example 2 0.104 0.101 0.098 0.101 Comparative Example 4 0.09 0.094 0.088 0.091 Experimental results demonstrate the significant functional role of ceramic precursors in constructing thermal insulation systems. During the hot pressing process, they contribute to the formation of a portion of the inorganic phase skeleton, effectively enhancing the material's thermal stability and heat-blocking capabilities. The Example 1 sample exhibited low thermal conductivity at all temperatures, particularly at high temperatures, where its thermal resistance outperformed that of other groups, demonstrating the interruption of heat conduction pathways by the ceramic component within the microstructure.

[0116] Further comparison revealed that Comparative Example 2, lacking a ceramic precursor, exhibited generally higher thermal conductivity, indicating a lack of effective internal thermal barriers. This resulted in a relatively continuous heat conduction path, making it difficult to disperse heat flow. This phenomenon is closely related to the inorganic component's inability to form thermally resistive interfaces or cavity structures within microregions, highlighting the irreplaceable role of the ceramic phase in the overall thermal insulation system.

[0117] Combining existing structural induction design with analysis of hot pressing process conditions, the experiment further validated the critical value of component-process synergy in the construction of functional materials. In multiphase material systems, the complementary inorganic-organic ratio and structural differentiation require precise process matching to fully realize their performance potential.

[0118] Experiment 3: Experimental Materials: Example 1 sample; Comparative Example 3 sample.

[0119] Experimental equipment: Vertical combustion tester; microbalance, vernier caliper, sample cutting tool; cotton pad (placed under the sample to determine whether the dripping will ignite).

[0120] Experimental steps: Sample preparation: Cut samples into standard test size, for example: 125mm×13mm×5mm (horizontal burning).

[0121] Ensure that all samples have flat surfaces, regular edges and no burrs.

[0122] Vertical burning test: Hang the sample vertically in the test fixture with a dry cotton pad placed under the sample.

[0123] Touch the free end of the sample with a standard flame (40–50 W butane flame, flame height approximately 20 mm) for 10 seconds.

[0124] Remove the flame and immediately record the first burning duration (t1).

[0125] After the flame is completely extinguished, light the sample again for 10 seconds and remove the flame.

[0126] Record the duration of the second burning (t2) and whether there is molten dripping that ignites the cotton pad.

[0127] Each group of samples was tested three times to ensure data consistency.

[0128] Flame retardancy is rated according to the UL-94 standard (V-0, V-1, V-2 or unqualified).

[0129] Data Records: First burning time t1 (s); second burning time t2 (s) whether molten dripping occurs; Whether the cotton pad is ignited (yes / no); residual carbon rate (%); final rating (UL-94), Experimental results (see Table 3): Table 3: Sample vertical combustion performance evaluation data table Sample type <![CDATA[t1(s)]]> <![CDATA[t2(s)]]> dripping ignition cotton pad Residual carbon rate (%) UL-94 rating Example 1 2.5 3 no 29.4 V-0 Comparative Example 3 8.8 11.6 yes 12.1 Unqualified Vertical combustion test results show that the introduction of a specific fire-enhancing component significantly improves the material's self-extinguishing and anti-dripping properties during combustion. The phosphate ester intermediates formed in this system contribute to the formation of the char structure during the initial pyrolysis phase, inhibiting the continued release of combustible gases and significantly reducing the flame propagation rate.

[0130] Furthermore, experimental results show that the stability of the carbonized structure is crucial for the secondary ignition. The reinforcing components promote the formation of a dense, continuous carbon layer during pyrolysis. This layer maintains its thermal barrier properties even under secondary flame impact, preventing further oxidation and combustion. This demonstrates the carbon layer's excellent thermal isolation and self-healing capabilities.

[0131] At the same time, by comparing the dripping behavior, it can be seen that the embodiment does not have the phenomenon of molten dripping ignition, indicating that the system structure maintains sufficient physical stability under the action of heat, avoiding melt migration and ignition expansion, thereby improving the overall flame retardant safety.

[0132] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A heat-insulating battery insulating gasket, characterized in that: The composition includes the following parts by weight: High temperature curing resin: 30-70 parts; Foaming agent: 0.5-5 parts; Ceramic precursor: 5-30 parts; Gradient structure inducer: 1-15 parts; Fire-enhancing component: 3-20 parts; Additives: 2-11 parts.

2. A heat-insulating battery insulating gasket according to claim 1, characterized in that: The foaming agent is melamine or azodicarbonamide; The additives include an antioxidant and a lubricant, wherein the antioxidant is a hindered phenol antioxidant and the lubricant is a metal stearate; The high-temperature curing resin includes a blend of methylphenyl vinyl silicone resin and boron-modified phenolic resin, and the mass ratio of the methylphenyl vinyl silicone resin to the boron-modified phenolic resin is 2:3-3:

2.

3. The heat-insulating battery insulating gasket according to claim 1, characterized in that: The ceramic precursor includes tetraethoxysilane and nano-scale silicon dioxide; The mass ratio of the tetraethoxysilane to the nano-scale silicon dioxide is 7:3-6:

1.

4. The heat-insulating battery insulating gasket according to claim 1, characterized in that: The gradient structure inducing agent includes polydimethylsiloxane grafted with acrylate and polypropylene microspheres grafted with maleic anhydride; The acrylate grafted modified polydimethylsiloxane is obtained by grafting vinyl-terminated polydimethylsiloxane with methyl methacrylate under the action of an initiator, wherein the initiator is benzoyl peroxide or azobisisobutyronitrile; The maleic anhydride grafted polypropylene microspheres are prepared by melt grafting polypropylene microspheres with maleic anhydride, wherein dicumyl peroxide or benzoyl peroxide is used as an initiator. The particle size of the maleic anhydride grafted polypropylene microspheres is 10-50 μm. The mass ratio of the acrylate grafted modified polydimethylsiloxane to the maleic anhydride grafted modified polypropylene microspheres is 3:2-4:

1.

5. A heat-insulating battery insulating gasket according to claim 1, characterized in that: The fire-enhancing component comprises ammonium polyphosphate and pentaerythritol; The degree of polymerization of the ammonium polyphosphate is 1000-3000, and the particle size of the pentaerythritol is 10-70 μm; The mass ratio of the ammonium polyphosphate to pentaerythritol is 2:1-4:

1.

6. A production process for a heat-insulating battery insulating gasket, for preparing a heat-insulating battery insulating gasket as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Mixing a high-temperature curing resin, a foaming agent, a ceramic precursor, a gradient structure inducing agent, a fire-enhancing component, and an additive according to a proportion to obtain a premix; S2, placing the premix in a mold for hot pressing to form a molded product with a density gradient structure through the action of a gradient structure inducer; S3. Curing the molded product with the density gradient structure at high temperature to obtain a heat-insulating battery insulating gasket.

7. The production process of a heat-insulating battery insulating gasket according to claim 6, characterized in that: The step S1 comprises: uniformly mixing a foaming agent, a ceramic precursor, a gradient structure inducing agent, a fire-enhancing component and an additive by dry mixing to obtain a solid mixture; The solid mixture is added to the high temperature curing resin and stirred until all components are evenly dispersed to obtain the premix.

8. The production process of a heat-insulating battery insulating gasket according to claim 6, characterized in that: The step S2 comprises: evenly spreading the premix in the mold cavity, closing the mold, and hot pressing the mold at a pressure of 5-15 MPa; The hot pressing process adopts staged heating: the mold temperature is raised to 60-80° C. and kept at this temperature for 5-15 minutes, and then further raised to 100-140° C. and kept at this temperature for 10-20 minutes to obtain a molded product with a density gradient structure.

9. The production process of a heat-insulating battery insulating gasket according to claim 6, characterized in that: The step S3 includes: placing the molded article with the density gradient structure in a curing device, heating it to 180-220°C in a nitrogen atmosphere with a purity of 99.5%-99.99% and maintaining the temperature for 1-3 hours, and then cooling it at a cooling rate of 1-10°C / minute for 30-120 minutes to obtain a heat-insulating battery insulating gasket.

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