A high-strength, lightweight polymer-based composite material for thermal insulation of power batteries and a preparation method thereof
Patent Information
- Application Number
- CN202610366181.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-24
- Publication Date
- 2026-08-28
AI Technical Summary
然而，这些材料存在一些固有缺陷：陶瓷纤维板和气凝胶毡机械强度较低，易粉化掉屑，在长期振动环境下可能失效；云母板密度较大，不利于电池包轻量化，且柔韧性差；膨胀型涂层隔热效果受厚度限制，且对基材附着力有较高要求
[0014]本发明与现有技术相比的有益效果是：1、优异的轻量化与隔热性能：空心玻璃微珠的引入显著降低了隔热板的密度（轻质），其内部封闭的稀薄气体空腔构成了高效的热阻隔单元，极大地降低了隔热板的导热系数，使复合材料具备卓越的隔热性能，渗入中间层（芯层）多孔片材的树脂-微珠复合体系，不仅强化了界面，其本身也成为一道附加的梯度隔热层，并与中间层孔隙中的静态空气协同，在厚度方向构建了更复杂、高效的多级热阻网络；2、革命性的结构互锁与界面强化：通过将空心玻璃微珠/环氧树脂体系主动涂覆并渗入多孔片材中间层表面及近表面孔隙，固化后在芯-皮界面形成“树脂钉扎”或“机械互锁”结构，从根本上解决了传统夹层材料界面粘结弱、易分层的关键痛点，实现了中间层与上下表层真正意义上的一体化；3、高强度与高刚度：玻璃纤维布作为连续增强体，为层压板提供了出色的拉伸、弯曲强度和抗冲击性能，克服了传统多孔隔热材料机械强度差的缺点，中间层低密度多孔片材提供核心的体积隔热和可压缩缓冲功能，能承受电池包内的机械振动和挤压；4、良好的阻燃性与安全性：环氧树脂基体本身可通过配方设计实现阻燃，添加的协同阻燃剂进一步提升了材料的防火等级，遇火时能有效抑制火焰传播，不产生熔滴，增强了电池系统的被动安全性，整体材料的阻燃设计确保在明火下具有自熄性，一体化结构在振动、冷热循环下可靠性极高；5、结构可设计性与工艺成熟：通过调整玻璃纤维布的层数、铺层角度和空心玻璃微珠的填充量，可以灵活调整板材的力学、热学性能以满足不同应用场景，制备工艺借鉴成熟的复合玻璃纤维布层压工艺，易于实现稳定批量生产；耐久可靠：复合电池隔热板结构致密，不易粉化、吸潮，具有良好的耐化学腐蚀性和长期环境稳定性，使用寿命长。
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Abstract
Description
Technical Field
[0001] This invention mainly relates to the field of battery thermal insulation materials technology, specifically to a high-strength, lightweight polymer-based composite material for power battery thermal insulation and its preparation method. Background Technology
[0002] With the rapid development of electric vehicles and large-scale energy storage power stations, the safety issues of electrochemical energy storage devices such as lithium-ion batteries are becoming increasingly prominent. Overcharging, short circuits, or thermal abuse can trigger thermal runaway, generating a large amount of heat that spreads rapidly within the battery pack, leading to serious safety accidents. Therefore, setting up efficient thermal insulation and flame-retardant barriers between battery cells or modules is a key measure to prevent the propagation of thermal runaway and improve the overall safety of the battery system.
[0003] Currently, commonly used battery insulation materials mainly include ceramic fiber boards, aerogel felts, mica boards, and intumescent flame-retardant coatings. However, these materials have some inherent drawbacks: ceramic fiber boards and aerogel felts have low mechanical strength, are prone to pulverization and shedding, and may fail under long-term vibration; mica boards have a high density, which is not conducive to lightweight battery packs, and they also have poor flexibility; the insulation effect of intumescent coatings is limited by thickness and has high requirements for substrate adhesion. Therefore, there is an urgent need to develop a composite insulation material that combines lightweight, high strength, excellent insulation performance, good formability, and long-term reliability. Summary of the Invention
[0004] (a) Technical problems to be solved In view of the above-mentioned problems, the present invention provides a high-strength, lightweight polymer-based composite material for heat insulation of power batteries. The raw materials for preparing the composite heat insulation sheet include hollow glass microspheres, epoxy resin, glass fiber cloth, curing agent, dimethylimidazolium, N,N-dimethylformamide, antioxidant, flame retardant, defoamer, and silane coupling agent. The mass ratio of each raw material is as follows: 10-40 parts hollow glass microspheres, 50-80 parts epoxy resin, 5-10 parts curing agent, and dimethylimidazolium... The raw materials are modified, formulated and blended to form a blended adhesive mainly composed of epoxy resin and hollow glass microspheres, which can be coated on the surface of modified glass fiber cloth or porous sheet. The adhesive is then dried in an oven to prepare a semi-cured heat insulation sheet. The heat insulation sheet is then stacked with insulating 7628 or 2116 semi-cured sheets in an alternating manner to form a heat insulation board with a composite sandwich structure with a symmetrical gradient distribution.
[0005] Furthermore, the silane coupling agent includes one or more of KH-550, KH-560, KH-570, and KH-591.
[0006] Furthermore, the fiberglass cloth is a plain, twill, or satin woven E-glass or S-glass cloth with a surface density of 100–300 g / m².
[0007] Furthermore, the porous sheet is an open-cell or semi-open-cell flexible material, including at least one of vacuum porous silicon, polyimide, phenolic resin, polyetherimide, and polyurethane. The porous sheet has a density of 0.03–0.30 g / cm³ and a thickness of 0.1–1 mm. The hollow glass microspheres have a true density of 0.15–0.60 g / cm³, a particle size distribution of 10–60 μm, and a compressive strength greater than 20 MPa.
[0008] Furthermore, the epoxy resin system is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, or their modified resins; the curing agent is at least one of amine curing agents or acid anhydride curing agents; the antioxidant is one or more of hindered phenolic antioxidants and phosphite antioxidants; the flame retardant is one or more of phosphorus-based flame retardants, nitrogen-based flame retardants, or their surface-modified products; and the defoamer is a polydimethylsiloxane defoamer or a polyether-modified silicone defoamer.
[0009] Furthermore, phosphorus-based flame retardants include ammonium polyphosphate and aluminum hypophosphite; nitrogen-based flame retardants include melamine cyanurate.
[0010] Furthermore, the thickness of the surface and bottom layers of the insulation board is 1.5–2 mm, the thickness of the middle layer is 0.1–1 mm, the total thickness of the composite insulation board is 3.5–4.5 mm, and the density is 0.80–1.70 g / cm³.
[0011] A method for preparing a high-strength, lightweight polymer-based composite material for power battery thermal insulation, comprising the following steps: S1: Surface modification treatment of hollow glass microspheres, glass fiber cloth and porous sheets is carried out using silane coupling agent to enhance the interfacial compatibility between hollow glass microspheres, glass fiber cloth and porous sheets and epoxy resin, and to improve the dispersibility of glass microspheres in epoxy resin system. S2: Preparation of epoxy resin-based composite adhesive system: Add curing agent and accelerator to an appropriate amount of N,N-dimethylformamide organic solvent, stir thoroughly for a certain time, then add epoxy resin, stir at 120-130℃ until completely dissolved, and then cool to obtain a primary mixture; then add a certain proportion of antioxidant, flame retardant and defoamer to the primary mixture in sequence, heat to 80±2℃ and stir for a predetermined time, and gel at 160±2℃ for 100-120 seconds to obtain epoxy resin composite adhesive system; S3: Under room temperature stirring conditions, the modified hollow glass microspheres are added to the epoxy resin composite adhesive system obtained in step S2, and the mixture is stirred continuously for 0.5 to 2 hours at a stirring speed of 400 to 450 r / min. Then, ultrasonic dispersion is performed to obtain the hollow glass microsphere / epoxy resin composite adhesive system. S4: At room temperature, the hollow glass microspheres / epoxy resin composite adhesive system obtained in step S3 is uniformly coated on the upper and lower surfaces of the modified glass fiber cloth and the modified porous sheet, and dried to form a resin layer; then pre-cured at 120-150℃ to obtain a semi-cured heat insulation sheet. S5: The semi-cured heat insulation sheet, porous sheet, and insulating semi-cured sheet obtained in step S4 are stacked and laid out according to the preset number of layers and direction. The top and bottom layers are semi-cured heat insulation sheets composed of multiple modified hollow glass microspheres / epoxy resin composites, the middle layer is a porous sheet composed of modified hollow glass microspheres / epoxy resin composites, and 7628 or 2116 insulating semi-cured sheets are sandwiched between the heat insulation sheet and the porous sheet. After stacking, the sheets are molded and placed in a hot press for hot pressing and curing. The hot pressing temperature is increased in steps from 125±5℃ to 160±5℃, the hot pressing pressure is 1~20MPa, and the hot pressing time is 2~8 hours. Then, the pressure is maintained for 2~6 hours, and then the sheets are naturally cooled to room temperature. After opening the mold, a multi-layer composite high-strength and lightweight heat insulation board for power batteries is obtained.
[0012] Furthermore, the modified glass fiber cloth and the modified porous sheet are prepared by the following steps: immersing the glass fiber cloth and the porous sheet in a silane coupling agent ethanol solution for 10-20 minutes, removing them, and drying them to obtain the modified glass fiber cloth and the modified porous sheet.
[0013] Furthermore, the modified hollow glass microspheres were prepared through the following steps: Step 1: Place the hollow glass microspheres in an environment of 80±5℃ for 2-3 hours to obtain dried hollow glass microspheres; Step 2: Prepare an ethanol-water solution by mixing anhydrous ethanol and distilled water at a mass ratio of 9:1. Then add silane coupling agent to the ethanol-water solution, mix thoroughly, adjust the pH value to 4-5, hydrolyze for 1 hour, and then add the dried hollow glass microspheres obtained in Step 1. Mix thoroughly to obtain the first mixture. Step 3: Treat the first mixture obtained in Step 2 in an 80°C hot water bath for 4 hours, while simultaneously treating it with ultrasound for 2-3 hours, then cool it to room temperature and filter it. Step 4: Dry in an 80℃ oven for 2~4 hours, then sieve to obtain modified hollow glass microspheres.
[0014] The beneficial effects of this invention compared to existing technologies are: 1. Excellent lightweight and thermal insulation performance: The introduction of hollow glass microspheres significantly reduces the density (lightweight) of the insulation board. The closed, rarefied gas cavities inside constitute a highly efficient thermal barrier unit, greatly reducing the thermal conductivity of the insulation board and giving the composite material excellent thermal insulation performance. The resin-microsphere composite system, which penetrates into the porous sheet of the intermediate layer (core layer), not only strengthens the interface but also becomes an additional gradient thermal insulation layer. It also works synergistically with the static air in the pores of the intermediate layer to improve thermal insulation performance in the thickness direction. 1. A more complex and efficient multi-level thermal resistance network was constructed; 2. Revolutionary structural interlocking and interface reinforcement: By actively coating and penetrating the hollow glass microsphere / epoxy resin system into the surface and near-surface pores of the porous sheet intermediate layer, a "resin pinning" or "mechanical interlocking" structure is formed at the core-skin interface after curing, fundamentally solving the key pain points of weak interfacial adhesion and easy delamination in traditional sandwich materials, and realizing true integration between the intermediate layer and the upper and lower surface layers; 3. High strength and high stiffness: Glass fiber cloth, as a continuous reinforcement, provides excellent strength for the laminate. The tensile, flexural strength, and impact resistance of the composite battery insulation material overcome the shortcomings of poor mechanical strength in traditional porous insulation materials. The low-density porous sheet in the middle layer provides core volumetric insulation and compressible buffering functions, and can withstand mechanical vibration and compression within the battery pack. 4. Good flame retardancy and safety: The epoxy resin matrix itself can be flame retardant through formulation design. The added synergistic flame retardants further improve the fire resistance rating of the material. When exposed to fire, it can effectively inhibit flame propagation and prevent the production of molten droplets, thus enhancing the passive safety of the battery system. The overall flame retardant design of the material ensures self-extinguishing properties under open flame, and the integrated structure has extremely high reliability under vibration and thermal cycling. 5. Structural designability and mature process: By adjusting the number of fiberglass cloth layers, the layup angle, and the filling amount of hollow glass microspheres, the mechanical and thermal properties of the board can be flexibly adjusted to meet different application scenarios. The preparation process draws on the mature composite fiberglass cloth lamination process, which is easy to achieve stable mass production. Durable and reliable: The composite battery insulation board has a dense structure, is not easy to pulverize or absorb moisture, has good chemical corrosion resistance and long-term environmental stability, and has a long service life. Attached Figure Description
[0015] Figure 1 This is a process flow diagram of the preparation method of the present invention. Detailed Implementation
[0016] The present invention will be further described below with reference to specific embodiments. The invention is explained through illustrative embodiments and descriptions, but is not intended to limit the invention.
[0017] Example 1: A high-strength, lightweight polymer-based composite material for heat insulation of power batteries. The raw materials for preparing the composite heat insulation sheet include hollow glass microspheres, epoxy resin, glass fiber cloth, curing agent, dimethylimidazole, N,N-dimethylformamide, antioxidant, flame retardant, defoamer, and silane coupling agent. The mass ratio of each raw material is as follows: 10-40 parts hollow glass microspheres, 50-80 parts epoxy resin, 5-10 parts curing agent, 2-5 parts dimethylimidazole, etc. The raw materials are modified, formulated and blended to form a blended adhesive mainly composed of epoxy resin and hollow glass microspheres that can be coated on the surface of modified glass fiber cloth or porous sheet. The semi-cured heat insulation sheet is prepared by drying in an oven. The heat insulation sheet and the insulating 7628 or 2116 semi-cured sheet are then stacked alternately to form a heat insulation board with a composite sandwich structure with a symmetrical gradient distribution.
[0018] Silane coupling agents include one or more of KH-550, KH-560, KH-570, and KH-591.
[0019] Fiberglass cloth is E-glass or S-glass cloth woven in plain, twill, or satin weave, with a surface density of 100–300 g / m².
[0020] The porous sheet is an open-cell or semi-open-cell flexible material, including at least one of vacuum porous silicon, polyimide, phenolic resin, polyetherimide, and polyurethane. The porous sheet has a density of 0.03 to 0.30 g / cm³ and a thickness of 0.1 to 1 mm. The hollow glass microspheres have a true density of 0.15 to 0.60 g / cm³, a particle size distribution of 10 to 60 μm, and a compressive strength greater than 20 MPa.
[0021] The epoxy resin system is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, or modified resin thereof; the curing agent is at least one of amine curing agent or acid anhydride curing agent; the antioxidant is one or more of hindered phenolic antioxidant and phosphite antioxidant; the flame retardant is one or more of phosphorus-based flame retardant, nitrogen-based flame retardant, or surface-modified products thereof; and the defoamer is polydimethylsiloxane defoamer or polyether-modified silicone defoamer.
[0022] Phosphorus-based flame retardants include ammonium polyphosphate and aluminum hypophosphite; nitrogen-based flame retardants include melamine cyanurate.
[0023] The thickness of the surface and bottom layers of the insulation board is 1.5–2 mm, the thickness of the middle layer is 0.1–1 mm, the total thickness of the composite insulation board is 3.5–4.5 mm, and the density is 0.80–1.70 g / cm³.
[0024] The surface of the insulation board made of the above materials consists of four layers of fabric, in the following order: Layer 1: Fiberglass cloth + epoxy / microspheres Layer 2: Fiberglass cloth + epoxy / microspheres Layer 3: Fiberglass cloth + epoxy / microspheres Layer 4: Fiberglass cloth + epoxy / microbeads; The intermediate layer is composed of (porous sheet) + (epoxy resin + microspheres), with a thickness of 0.5–1.0 mm. The bottom layer consists of four layers of fabric, in the following order: Layer 1: Fiberglass cloth + epoxy / microspheres Layer 2: Fiberglass cloth + epoxy / microspheres Layer 3: Fiberglass cloth + epoxy / microspheres Layer 4: Fiberglass cloth + epoxy / microspheres.
[0025] The bottom and top layers of fabric are symmetrically arranged with the middle layer as the axis, and the total thickness of the insulation board is approximately 4.0 mm. At room temperature (25℃), the in-plane thermal conductivity is less than 0.20 W / (m·K), the tensile strength is ≥350 MPa, the flexural strength is ≥450 MPa, and the parallel-layer impact strength is ≥50 kJ / m. 2 After being placed at a low temperature of -40℃ for 240 hours, the tensile strength is ≥300MPa, the flexural strength is ≥400MPa, and the Shore hardness is >80HD; after being placed at a high temperature of 85℃ for 1000 hours, the tensile strength is ≥300MPa, the flexural strength is ≥400MPa, and the Shore hardness is >80HD; it meets the UL94 V0 flame retardant rating.
[0026] Example 2: As Figure 1 The method for preparing a high-strength, lightweight polymer-based composite material for power battery heat insulation, as shown above, includes the following steps: S1: Surface modification treatment of hollow glass microspheres, glass fiber cloth and porous sheets is carried out using silane coupling agent to enhance the interfacial compatibility between hollow glass microspheres, glass fiber cloth and porous sheets and epoxy resin, and to improve the dispersibility of glass microspheres in epoxy resin system. S2: Preparation of epoxy resin-based composite adhesive system: Add curing agent and accelerator to an appropriate amount of N,N-dimethylformamide organic solvent, stir thoroughly for a certain time, then add epoxy resin, stir at 120-130℃ until completely dissolved, and then cool to obtain a primary mixture; then add a certain proportion of antioxidant, flame retardant and defoamer to the primary mixture in sequence, heat to 80±2℃ and stir for a predetermined time, and gel at 160±2℃ for 100-120 seconds to obtain epoxy resin composite adhesive system; S3: Under room temperature stirring conditions, the modified hollow glass microspheres are added to the epoxy resin composite adhesive system obtained in step S2, and the mixture is stirred continuously for 0.5 to 2 hours at a stirring speed of 400 to 450 r / min. Then, ultrasonic dispersion is performed to obtain the hollow glass microsphere / epoxy resin composite adhesive system. S4: At room temperature, the hollow glass microspheres / epoxy resin composite adhesive system obtained in step S3 is uniformly coated on the upper and lower surfaces of the modified glass fiber cloth and the modified porous sheet, and dried to form a resin layer; then pre-cured at 120-150℃ to obtain a semi-cured sheet. S5: The semi-cured sheet obtained in step S4 is stacked and laid out according to the preset number of layers and direction. The top and bottom layers are multiple sheets of modified hollow glass microspheres / epoxy resin composite glass fiber cloth, and the middle layer is a modified hollow glass microspheres / epoxy resin composite porous sheet. After stacking, it is molded and placed in a hot press for hot pressing and curing. The hot pressing temperature is increased in steps from 125±5℃ to 160±5℃, the hot pressing pressure is 0.1~20MPa, and the hot pressing time is 2~8 hours. Then, it is held under pressure and naturally cooled to room temperature. After opening the mold, a multi-layer composite battery heat insulation board is obtained.
[0027] In S4, the coating method of the hollow glass microsphere / epoxy resin composite adhesive system on the surface of glass fiber cloth and porous sheet can be achieved by scraping, dip coating, vacuum coating, solution casting, compression molding, injection molding, extrusion coating or other applicable methods known in the art.
[0028] Modified glass fiber cloth and modified porous sheet are prepared by the following steps: immersing glass fiber cloth and porous sheet in silane coupling agent ethanol solution for 10-20 minutes, removing them, and drying them to obtain modified glass fiber cloth and modified porous sheet.
[0029] Modified hollow glass microspheres were prepared through the following steps: Step 1: Place the hollow glass microspheres in an environment of 80±5℃ for 2-3 hours to obtain dried hollow glass microspheres; Step 2: Prepare an ethanol-water solution by mixing anhydrous ethanol and distilled water at a mass ratio of 9:1. Then add silane coupling agent to the ethanol-water solution, mix thoroughly, adjust the pH value to 4-5, hydrolyze for 1 hour, and then add the dried hollow glass microspheres obtained in Step 1. Mix thoroughly to obtain the first mixture. Step 3: The first mixture obtained in Step 2 is treated in a hot water bath at 80°C for 4 hours, and simultaneously treated with ultrasound for 2-3 hours. After cooling to room temperature, it is sieved to obtain modified hollow glass microspheres.
[0030] Specific operating procedure: Immerse the glass fiber cloth and 0.5mm thick porous vacuum silicon sheet in KH-550 / 90% ethanol solution for 10-20 minutes, remove and dry to obtain modified glass fiber cloth and porous vacuum silicon sheet, and cut them into 30cm×30cm size for later use.
[0031] Weigh a certain amount of hollow glass microspheres with a true density of 0.40±0.02 g / cm³ and an average particle size of 40 μm, and dry them at 80±5℃ for 2–3 h. Add 1.5% of the silane coupling agent KH-550 to a 90% ethanol solution according to the mass of the hollow glass microspheres, adjust the pH value to 4–5, and hydrolyze for 1 h. Then add the dried hollow glass microspheres, mechanically stir at 200 r / min, treat in a hot water bath at 80℃ for 4 h, and then treat with ultrasound for 2–3 h. Cool to room temperature and sieve to obtain modified hollow glass microspheres.
[0032] Eight parts of dicyandiamide and two parts of dimethylimidazole were added to a reactor, and an appropriate amount of DMF (N,N-dimethylformamide) was added and stirred thoroughly for 1 hour. Then, 85 parts of epoxy resin were added to the reactor and stirred and dissolved at 120-130°C for 2 hours. The temperature was then lowered to 80°C, and two parts of antioxidant, two parts of defoamer, and one part of silane coupling agent were added sequentially. The mixture was stirred for 0.5 hours and then heated to 160°C to gel for 100-120 seconds to obtain a homogeneous epoxy resin composite liquid system.
[0033] At 25℃ and under stirring at 200r / min, the modified hollow glass microspheres were slowly added to the epoxy resin composite adhesive system. After stirring for 2 hours, the system was further ultrasonically dispersed for 40 minutes to obtain the hollow glass microsphere / epoxy resin composite adhesive system.
[0034] The hollow glass microsphere / epoxy resin composite adhesive system is uniformly coated onto the upper and lower surfaces of the modified glass fiber cloth and porous vacuum silicon sheet by a scraper. After drying, a resin layer is formed. The mixture is then dried at room temperature for 12 hours and pre-cured at 130±5℃ for 10 minutes to obtain a semi-cured sheet.
[0035] The semi-cured sheets are stacked in a predetermined number of layers and direction. The top and bottom layers each consist of four hollow glass microsphere / epoxy resin composite glass fiber cloth sheets, and the middle layer consists of one hollow glass microsphere / epoxy resin composite porous vacuum silicon sheet. The sheets are pushed into a hot press, the pressure is adjusted to 1MPa, and the temperature is heated to 125℃~135℃ for 2 hours. Then the temperature is slowly increased to 160±5℃ and held for 2 hours. The pressure is maintained and the sheets are allowed to cool naturally to room temperature. The mold is then opened to obtain a multi-layer composite battery heat insulation board.
[0036] The performance results of the composite battery heat shield prepared in Example 2 above are shown in the table below:
[0037]
[0038] The density of the battery heat shield is 1.505 g / cm³. 3 It possesses excellent mechanical properties: tensile strength reaches 365MPa, impact strength is 55kJ / m², and flexural strength is as high as 475MPa; in terms of thermal and electrical properties, its thermal conductivity is low, at 0.19W / (m·K), indicating that it has good heat insulation capabilities; its dielectric strength is 8kV / mm, its hardness (tested at -40℃) is 85HD, and its flame retardant performance meets the UL94 V0 flame retardant rating.
[0039] Unmodified hollow glass microspheres are hydrophilic and rich in silanol groups (-Si-OH), resulting in poor compatibility with the hydrophobic epoxy resin matrix. The interaction between the two is mainly physical mechanical interlocking and van der Waals forces, leading to a very fragile interfacial bond. KH-550-modified hollow glass microspheres, however, change their surface from hydrophilic to oleophilic, further improving their dispersibility and preventing agglomeration. The modification also reduces interfacial tension between the two phases, enhancing interfacial bonding and effectively improving the dispersibility of hollow glass microspheres in epoxy resin. This uniform and stable hollow glass microsphere-epoxy resin composite adhesive system not only optimizes the material's microstructure but also further enhances the toughness of the battery heat shield, enabling the product to more effectively transfer and disperse stress under load. The strong interfacial bond allows the hollow glass microspheres to truly bear the load, preventing crack propagation and effectively improving impact and tensile bending strength.
[0040] After modifying glass fiber cloth and porous vacuum silicon sheets with KH-550, the aminopropyl groups in the KH-550 molecule can react chemically with the hydroxyl groups on the surface of glass fiber and vacuum silicon to form stable chemical bonds, thereby enhancing their bonding force with the epoxy resin matrix, preventing delamination and debonding, and improving the overall strength of the composite insulation board. KH-550 has good wetting properties, which can reduce the interfacial tension between glass fiber and resin matrix, promote the full wetting of glass fiber cloth and porous vacuum silicon sheets by resin, reduce pores and defects in composite materials, and improve the density and appearance quality of the product.
[0041] The modified fiberglass cloth serves as a reinforcing layer, providing excellent tensile strength, puncture resistance, and dimensional stability. The modified porous vacuum silicon sheet acts as the intermediate layer (core layer), with its core function being to significantly improve the overall structural bending stiffness and impact resistance. Through its lightweight porous structure, it absorbs impact energy, together constructing a "rigid-flexible" sandwich system. This ensures that the heat insulation board maintains structural integrity during the daily operation of the battery module, while avoiding the impact on energy density due to excessive weight gain. Furthermore, it maintains the bending stiffness of the laminate and resists deformation under external forces.
[0042] Any aspects not covered in this invention are applicable to existing technologies.
Claims
1. A high-strength, lightweight polymer-based composite material for heat insulation of power batteries, characterized in that, The raw materials for preparing composite thermal insulation sheets include hollow glass microspheres, epoxy resin, glass fiber cloth, curing agent, dimethylimidazole, N,N-dimethylformamide, antioxidant, flame retardant, defoamer, and silane coupling agent. The raw materials are mixed in the following mass ratios: 10-40 parts hollow glass microspheres, 50-80 parts epoxy resin, 5-10 parts curing agent, 2-5 parts dimethylimidazole, 1-4 parts antioxidant, 5-10 parts flame retardant, 1-3 parts defoamer, and 1-3 parts silane coupling agent. The raw materials are modified, formulated, and blended to form a blended adhesive mainly composed of epoxy resin and hollow glass microspheres that can be coated on the surface of modified glass fiber cloth or porous sheets. The mixture is then dried in an oven to prepare a semi-cured thermal insulation sheet. The thermal insulation sheet is then stacked alternately with insulating 7628 or 2116 semi-cured sheets to form a composite sandwich structure thermal insulation board with a symmetrical gradient distribution.
2. The high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 1, characterized in that, The silane coupling agent includes one or more of KH-550, KH-560, KH-570, and KH-591.
3. The high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 1, characterized in that, The fiberglass cloth is a plain, twill, or satin woven E-glass or S-glass cloth with a surface density of 100–300 g / m².
4. The high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 1, characterized in that, The porous sheet is an open-cell or semi-open-cell flexible material, including at least one of vacuum porous silicon, polyimide, phenolic resin, polyetherimide, and polyurethane. The porous sheet has a density of 0.03 to 0.30 g / cm³ and a thickness of 0.1 to 1 mm. The hollow glass microspheres have a true density of 0.15 to 0.60 g / cm³, a particle size distribution of 10 to 60 μm, and a compressive strength greater than 20 MPa.
5. The high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 1, characterized in that, The epoxy resin system is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, or modified resin thereof; the curing agent is at least one of amine curing agent or acid anhydride curing agent; the antioxidant is one or more of hindered phenolic antioxidant and phosphite antioxidant; the flame retardant is one or more of phosphorus-based flame retardant, nitrogen-based flame retardant, or surface-modified products thereof; and the defoamer is polydimethylsiloxane defoamer or polyether-modified silicone defoamer.
6. The high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 5, characterized in that, Phosphorus-based flame retardants include ammonium polyphosphate and aluminum hypophosphite; nitrogen-based flame retardants include melamine cyanurate.
7. The high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 1, characterized in that, The thickness of the surface and bottom layers of the insulation board is 1.5–2 mm, the thickness of the middle layer is 0.1–1 mm, the total thickness of the composite insulation board is 3.5–4.5 mm, and the density is 0.80–1.70 g / cm³.
8. A method for preparing a high-strength, lightweight polymer-based composite material for power battery thermal insulation, comprising the following steps: (The method utilizes the high-strength, lightweight polymer-based composite material for power battery thermal insulation as described in any one of claims 1-7) S1: Surface modification treatment of hollow glass microspheres, glass fiber cloth and porous sheets is carried out using silane coupling agent to enhance the interfacial compatibility between hollow glass microspheres, glass fiber cloth and porous sheets and epoxy resin, and to improve the dispersibility of glass microspheres in epoxy resin system. S2: Preparation of epoxy resin-based composite adhesive system: Add curing agent and accelerator to an appropriate amount of N,N-dimethylformamide organic solvent, stir thoroughly for a certain time, then add epoxy resin, stir at 120-130℃ until completely dissolved, and then cool to obtain a primary mixture; then add a certain proportion of antioxidant, flame retardant and defoamer to the primary mixture in sequence, heat to 80±2℃ and stir for a predetermined time, and gel at 160±2℃ for 100-120 seconds to obtain epoxy resin composite adhesive system; S3: Under room temperature stirring conditions, the modified hollow glass microspheres are added to the epoxy resin composite adhesive system obtained in step S2, and the mixture is stirred continuously for 0.5 to 2 hours at a stirring speed of 400 to 450 r / min. Then, ultrasonic dispersion is performed to obtain the hollow glass microsphere / epoxy resin composite adhesive system. S4: At room temperature, the hollow glass microspheres / epoxy resin composite adhesive system obtained in step S3 is uniformly coated on the upper and lower surfaces of the modified glass fiber cloth and the modified porous sheet, and dried to form a resin layer; then pre-cured at 120-150℃ to obtain a semi-cured heat insulation sheet. S5: The semi-cured heat insulation sheet, porous sheet, and insulating semi-cured sheet obtained in step S4 are stacked and laid out according to the preset number of layers and direction. The top and bottom layers are semi-cured heat insulation sheets composed of multiple modified hollow glass microspheres / epoxy resin composites, the middle layer is a porous sheet composed of modified hollow glass microspheres / epoxy resin composites, and 7628 or 2116 insulating semi-cured sheets are sandwiched between the heat insulation sheet and the porous sheet. After stacking, the sheets are molded and placed in a hot press for hot pressing and curing. The hot pressing temperature is increased in steps from 125±5℃ to 160±5℃, the hot pressing pressure is 1~20MPa, and the hot pressing time is 2~8 hours. Then, the pressure is maintained for 2~6 hours, and then the sheets are naturally cooled to room temperature. After opening the mold, a multi-layer composite high-strength and lightweight heat insulation board for power batteries is obtained.
9. A method for preparing a high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 8, characterized in that, Modified glass fiber cloth and modified porous sheet are prepared by the following steps: immersing glass fiber cloth and porous sheet in silane coupling agent ethanol solution for 10-20 minutes, removing them, and drying them to obtain modified glass fiber cloth and modified porous sheet.
10. A method for preparing a high-strength, lightweight polymer-based composite material for heat insulation of power batteries according to claim 8, characterized in that, Modified hollow glass microspheres were prepared through the following steps: Step 1: Place the hollow glass microspheres in an environment of 80±5℃ for 2-3 hours to obtain dried hollow glass microspheres; Step 2: Prepare an ethanol-water solution by mixing anhydrous ethanol and distilled water at a mass ratio of 9:
1. Then add silane coupling agent to the ethanol-water solution, mix thoroughly, adjust the pH value to 4-5, hydrolyze for 1 hour, and then add the dried hollow glass microspheres obtained in Step 1. Mix thoroughly to obtain the first mixture. Step 3: Treat the first mixture obtained in Step 2 in an 80°C hot water bath for 4 hours, while simultaneously treating it with ultrasound for 2-3 hours, then cool it to room temperature and filter it. Step 4: Dry in an 80℃ oven for 2~4 hours, then sieve to obtain modified hollow glass microspheres.