High-environmental-adaptability carbon fiber composite material, preparation method and energy storage battery box

Abstract

The invention relates to the field of carbon fiber composite materials, in particular to a high-environmental-adaptability carbon fiber composite material, a preparation method and an energy storage battery box, the high-environmental-adaptability carbon fiber composite material comprises a carbon fiber reinforcement body, a silicone rubber combination body and an epoxy resin matrix, the silicone rubber combination body comprises, by weight, 10-12 parts of an epoxy-polyether-fluorosiloxane triblock copolymer, 10-12 parts of a silane coupling agent, 1-3 parts of a coupling agent, 1-3 parts of a coupling agent and 1-3 parts of a coupling agent. The invention relates to a high-temperature-resistant silicone rubber, which is prepared from the following components in parts by weight: 4 to 6 parts of polymethylhydrosiloxane cross-linking agent, 1 to 2 parts of Karst platinum catalyst, 0.12 to 0.18 part of methyl butynol, 0.08 to 0.12 part of vinyl-terminated low-hydrogen-content fluorosilicone oil, 1 to 2 parts of perfluorobutyl glycidyl ether, 0.3 to 0.5 part of polyether modified siloxane and the balance of water. Active groups at two ends of the epoxy-polyether-fluorosiloxane triblock copolymer are covalently bonded with the epoxy resin and the carbon fiber respectively, so that three-phase molecular-level gradient crosslinking is constructed, the surface energy difference between the fluorosiloxane and the epoxy resin is balanced, the problem of two-phase incompatibility is solved, and the adaptability of the CFRP to a severe environment is improved.

Description

Technical Field

[0001] This application relates to the field of carbon fiber composite materials, and in particular to a highly environmentally adaptable carbon fiber composite material, a preparation method thereof, and an energy storage battery box. Background Technology

[0002] Carbon fiber reinforced epoxy resin (CFRP) composites possess advantages such as high strength, high temperature resistance, and corrosion resistance, making them suitable for manufacturing battery pack housings for new energy vehicles or energy storage battery boxes. While achieving weight reduction, they can also adapt to various environments to a certain extent. However, the significant difference in thermal expansion coefficients between epoxy resin and carbon fiber, coupled with residual shrinkage stress generated during curing, and the superposition of these two types of interfacial stresses, can easily lead to interfacial debonding, interlaminar cracking, performance degradation, and even structural failure in complex environments, limiting their large-scale application in harsh environments.

[0003] In the manufacture of some carbon fiber composite materials, silicone rubber is added to modify epoxy resin. By covalently crosslinking the silicone rubber with both carbon fiber and epoxy resin, the problems of poor interfacial compatibility and interfacial stress concentration are solved, thus improving the impact strength of the composite material compared with conventional CFRP without silicone rubber. For example, the epoxy resin / carbon fiber composite material and its preparation method are disclosed in announcement number CN104774431B.

[0004] The CFRP mentioned above uses ordinary methyl vinyl silicone rubber, which cannot balance the surface energy difference between siloxane and epoxy resin. Even if basic cross-linking is achieved, it can only form a macroscopic two-phase interface rather than a molecular-level gradient transition. Under long-term humid heat and salt spray environment, corrosive media can easily penetrate along the microcracks at the interface, leading to interface debonding and a cliff-like decline in performance. The stability of CFRP in harsh environments needs to be improved. Summary of the Invention

[0005] To address the interfacial stability issues caused by the difference in surface energy between the two phases and improve the adaptability of CFRP to harsh environments, this application provides a highly environmentally adaptable carbon fiber composite material, a preparation method, and an energy storage battery box.

[0006] Firstly, the high environmental adaptability carbon fiber composite material provided in this application adopts the following technical solution.

[0007] Highly environmentally adaptable carbon fiber composite material, comprising a carbon fiber reinforcement, a silicone rubber binder, and an epoxy resin matrix. The silicone rubber binder, by weight, comprises: 10-12 parts of an epoxy-polyether-fluorosiloxane triblock copolymer, 4-6 parts of a polymethylhydrosiloxane crosslinking agent, 1-2 parts of a caster platinum catalyst, 0.12-0.18 parts of methylbutyninol, 0.08-0.12 parts of a vinyl-terminated low-hydrofluoric acid silicone oil, 1-2 parts of perfluorobutyl glycidyl ether, and 0.3-0.5 parts of a polyether-modified siloxane.

[0008] By adopting the above technical solution and designing an epoxy-polyether-fluorosiloxane triblock copolymer, the surface energy difference between fluorosiloxane and epoxy resin is balanced, solving the industry pain point of two-phase incompatibility. The active groups at both ends of the epoxy-polyether-fluorosiloxane triblock copolymer can be covalently bonded to epoxy resin and carbon fiber respectively, constructing a three-phase molecular-level gradient crosslinking structure of carbon fiber-fluorosilicone rubber-epoxy resin, which greatly improves the interfacial bonding strength and long-term stability, and reduces the possibility of interfacial debonding failure under humid heat and salt spray conditions.

[0009] In addition, methylbutyninol is used as the main retarder, and vinyl-terminated low-hydrofluorine silicone oil is used as a non-competitive rate regulator. The main retarder and the non-competitive rate regulator work synergistically to eliminate the antagonistic risk of traditional weak coordination retarders. This ensures that the room temperature pot life of the adhesive is extended as much as possible to meet the storage and process requirements of continuous mass production. At the same time, it can release catalytic activity in a smooth and controllable manner, avoiding concentrated exothermic reaction and product cracking. This perfectly balances the core contradiction between the storage stability of the adhesive and the curing reactivity.

[0010] Perfluorobutyl glycidyl ether is used as a diluent, and polyether-modified siloxane is used as a wetting agent. The diluent and wetting agent work together to reduce the viscosity of the system while ensuring that the contact angle of the silicone rubber compound on the surface of the carbon fiber reinforcement is small, so as to achieve complete spreading and wetting as much as possible. This simultaneously enhances the chemical corrosion resistance of the system, and ultimately endows the silicone rubber compound with excellent low-temperature flexibility, high-temperature resistance and media penetration resistance, thereby improving the environmental adaptability of carbon fiber composites from the core layer.

[0011] Optionally, the carbon fiber reinforcement comprises, by weight: 100 parts carbon fiber cloth and 3-5 parts aminofluorosilane coupling agent.

[0012] By adopting the above technical solution, carbon fiber cloth is used as the rigid load-bearing body. The matching aminofluorosilane coupling agent can build a stable covalent bond bridge between carbon fiber and fluorosilicone rubber, make up for the local activity fluctuations of plasma modification, and at the same time shield the polar groups of excessive surface oxidation, stabilize the interfacial compatibility, and improve the interfacial shear strength between carbon fiber and fluorosilicone rubber compared with untreated carbon fiber.

[0013] Optionally, the epoxy resin matrix comprises, by weight: 10 parts of bisphenol F type epoxy resin, 3-5 parts of phenolic type epoxy resin, 2-3 parts of polyetheramine curing agent D-230, 0.3-0.5 parts of cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.1-0.3 parts of BYK-163 dispersant, 0.1-0.3 parts of silicone defoamer, and 0.2-0.4 parts of BYK-410 rheology modifier.

[0014] By adopting the above technical solution, the composite matrix of bisphenol F epoxy resin and phenolic epoxy resin can take into account both low viscosity and high temperature resistance. The low viscosity of bisphenol F epoxy resin is suitable for the subsequent HP-RTM high-pressure injection mass production process, and phenolic epoxy resin can significantly increase the glass transition temperature of the system, solve the problem of mechanical property decay of composite materials at high temperature, and ensure structural stability over a wide temperature range.

[0015] Polyetheramine curing agent D-230 is a medium-temperature curing agent that matches the gradient curing program of the system. It also has an ultra-long pot life at 70℃, which can avoid flow channel blockage and filling difficulties caused by a sudden increase in viscosity during injection. The low addition amount of cationic modified hydroxylated fluorinated boron nitride nanosheets can construct a global labyrinth barrier structure in the resin matrix, which can significantly improve the resistance to media penetration and high temperature resistance, while avoiding the problem of excessive system viscosity caused by high addition amount.

[0016] The synergistic action of BYK-163 dispersant, silicone defoamer, and BYK-410 rheology modifier can precisely stabilize the system viscosity within a suitable range to match the HP-RTM three-step injection molding process window. At the same time, it reduces the porosity of the product, solves problems such as viscosity fluctuations, uneven filling, and pore defects in the resin system during mass production, and ensures the density and batch stability of the product.

[0017] Secondly, the method for preparing highly environmentally adaptable carbon fiber composite materials provided in this application adopts the following technical solution.

[0018] A method for preparing highly environmentally adaptable carbon fiber composite materials includes the following steps.

[0019] S1. Pre-treat and activate the carbon fiber cloth to obtain carbon fiber reinforcement;

[0020] S2. Prepare a liquid silicone rubber bond;

[0021] S3. The carbon fiber reinforcement is immersed in liquid silicone rubber composite, and after being taken out and air-dried, a carbon fiber preform with a fluorosilicone rubber layer on the surface is obtained.

[0022] S4. Prepare a liquid epoxy resin matrix and impregnate the liquid epoxy resin matrix into the carbon fiber preform to obtain the preform to be cured.

[0023] S5. Curing treatment is performed on the preform to be cured.

[0024] By adopting the above technical solutions and matching the composite material formulation system, a closed-loop process of gradient modification of carbon fiber surface, gradient coating and pre-crosslinking of silicone rubber and impregnation and curing of epoxy resin is formed. This process can fully realize the design goal of three-phase molecular-level gradient crosslinking structure, solve the core problems of weak interfacial bonding and poor performance synergy in existing processes, and simultaneously achieve excellent mechanical properties and high environmental adaptability of composite materials.

[0025] Furthermore, by employing a pre-processing technique involving carbon fiber modification and silicone rubber pre-coating, the fundamental problems of high residual stress at the interface and easy cracking during long-term service caused by the mismatch in thermal expansion coefficients between carbon fiber and epoxy resin are resolved. The resulting composite material exhibits significantly improved impact strength compared to conventional silicone rubber-free systems, while also possessing excellent resistance to salt spray, damp heat, and alternating high and low temperatures, meeting the long-term service requirements under harsh operating conditions.

[0026] Optionally, step S1 specifically includes the following steps:

[0027] S11. Soak the carbon fiber cloth in acetone solution and then vacuum dry it to remove the sizing agent and impurities.

[0028] S12. The dried carbon fiber cloth is subjected to cold plasma treatment using a mixture of argon, HFO-1234yf and oxygen.

[0029] S13. The carbon fiber cloth treated with cold plasma is immersed in an ethanol solution of aminofluorosilane coupling agent and ultrasonically impregnated, and then vacuum dried to obtain carbon fiber reinforcement.

[0030] By adopting the above technical solution, the acetone soaking combined with vacuum drying impurity removal process can thoroughly remove the slurry and low molecular weight impurities on the carbon fiber surface, providing a clean reaction interface for subsequent plasma activation and coupling agent grafting, and ensuring the uniformity of surface modification and grafting rate.

[0031] The cold plasma treatment process using a mixture of argon, HFO-1234yf, and oxygen gas replaces the traditional air plasma treatment. This process solves the problem of strength loss caused by excessive etching of the carbon fiber body due to the strong oxidizing active oxygen species in the traditional process. It can simultaneously introduce highly active -CF bonds, hydroxyl groups, and carboxyl groups on the carbon fiber surface. The active groups have a long half-life, which solves the problem of rapid decay of carbon fiber activity during mass production.

[0032] The ultrasonic impregnation combined with vacuum drying process of aminofluorosilane coupling agent can form a monolayer covalently bonded fluorosilane film on the surface of activated carbon fiber. This provides stable active sites for subsequent gradient crosslinking, shields the surface of a small number of excessively oxidized polar groups, stabilizes the surface energy of carbon fiber, ensures its long-term interfacial compatibility with fluorosilicone rubber, avoids loss of carbon fiber strength, and ensures a high strength retention rate of carbon fiber after treatment.

[0033] Optionally, the ratio of argon, HFO-1234yf and oxygen is 90:7:3.

[0034] By adopting the above technical solution, the fluorination efficiency of plasma treatment and the control of carbon fiber body damage are balanced. The 3% low proportion of oxygen only assists the C=C bond breaking of HFO-1234yf, which greatly improves the yield of fluorine free radicals. At the same time, it minimizes the generation of highly oxidizing active oxygen species, avoids excessive etching of carbon fiber surface and damage to graphite structure, and ensures that the increase in the ratio of D peak to G peak intensity of carbon fiber is within a certain range.

[0035] A 7% HFO-1234yf content ensures that the effective fluorination grafting rate of the carbon fiber surface meets the standard, resulting in a lower carbon fiber surface energy, a larger water contact angle, and a significant improvement in its interfacial compatibility with fluorosilicone rubber.

[0036] Using 90% argon as a carrier gas ensures stable plasma discharge. Combined with the roll-to-roll process, it can achieve a small deviation in the uniformity of activity between the edge and center of wide-width carbon fiber cloth, solving the industry pain point of uneven surface modification of carbon fiber during wide-width mass production.

[0037] Optionally, an insulating barrier layer is deposited on the carbon fiber reinforcement after S1 and before S3, the insulating barrier layer comprising cation-modified hydroxylated fluorinated boron nitride nanosheets.

[0038] By adopting the above technical solution, an insulating barrier layer containing cation-modified hydroxylated fluorinated boron nitride nanosheets is deposited on the surface of carbon fiber reinforcement. A dense, continuous and uniform nano-insulating protective layer can be formed on the surface of carbon fiber monofilament. This fundamentally blocks the galvanic corrosion channel between carbon fiber and metal connectors under salt spray and humid heat environments, solves the core failure risk of carbon fiber composite materials in long-term service, and greatly improves the service life and environmental adaptability of the products.

[0039] Cationic modified hydroxylated fluorinated boron nitride nanosheets can achieve uniform deposition on the surface of carbon fiber monofilaments, without the problems of cross-point node accumulation, agglomeration and cracking. The thickness of the deposited layer can be precisely controlled with small thickness tolerance throughout the entire area. It will not block the fiber weaving gaps and will not affect the subsequent silicone rubber and epoxy resin impregnation process. At the same time, it forms the first layer of nano barrier to prevent corrosive media from penetrating into the interior of the composite material, further improving the media resistance performance.

[0040] The insulation barrier layer deposition process is set before the silicone rubber coating, which can achieve pre-insulation protection of the carbon fiber body and form a multi-level protection system with the subsequent fluorosilicone rubber layer and epoxy resin matrix.

[0041] Optionally, S4 is impregnated using the HP-RTM process, which consists of three injection steps: the first stage, with an injection pressure of 2.5 MPa and an injection rate of 8 g / s, injects the liquid epoxy resin matrix to fill 80% of the mold cavity; the second stage, with an injection pressure of 5 MPa and a holding pressure of 20 s; and the third stage, with an injection pressure of 10 MPa and a holding pressure of 60 s.

[0042] By adopting the above technical solution, the three-step gradient HP-RTM injection process perfectly matches the characteristics of fluorosilicone rubber modified carbon fiber preforms. The first stage of low-pressure and low-speed injection allows epoxy resin to slowly penetrate the surface network of the fluorosilicone rubber layer under low pressure, forming a stable interface transition layer. This completely avoids the scouring and damage of the fluorosilicone rubber layer by high-pressure fluid, eliminates the white line defect of unwetted interface, and solves the interface delamination problem that is prone to occur in the traditional HP-RTM process.

[0043] The second stage of medium-pressure filling transition allows the epoxy resin to completely fill all corners of the cavity, fully wet the interface between the carbon fiber bundles and the adhesive layer, and eliminate dead corners and bubble defects in the cavity; the third stage of high-pressure compaction can completely densify the composite material, control the internal porosity of the product to a small size, and significantly improve the mechanical properties and structural stability of the product.

[0044] Optionally, the curing process in S5 is a four-stage heating and curing process: the first stage is 85℃ for 20 minutes; the second stage is 165℃ for 40 minutes; the third stage is 100℃ for 30 minutes; and the fourth stage is 40℃ for 30 minutes.

[0045] By adopting the above technical solution, the four-stage gradient heating continuous curing process shortens the total curing cycle compared to the traditional multi-stage curing process. The matching roller tunnel oven enables continuous production, reduces equipment length, lowers production energy consumption, significantly improves mass production efficiency, and reduces manufacturing costs.

[0046] The first stage of gentle preheating can achieve a smooth transition of the product from the 70°C mold temperature, avoid thermal shock cracking, and ensure uniform temperature throughout the product, with small temperature differences between the upper and lower surfaces and the left, middle and right sides.

[0047] The second stage of high-temperature curing can simultaneously complete the deep cross-linking of the interface between fluorosilicone rubber and epoxy resin, the curing of the epoxy resin body and post-curing. After this stage, the resin curing degree is high, forming a stable three-way interpenetrating network structure, ensuring the mechanical properties and environmental stability of the product.

[0048] The third and fourth stage dual-gradient cooling process can uniformly eliminate internal stress in the product, avoid warping deformation caused by rapid cooling, and steadily reduce the product temperature to room temperature, ensuring dimensional stability after mold opening and a small thermal deformation rate. At the same time, it solves the problem of uneven curing caused by temperature differences between the upper and lower surfaces and the lateral direction in traditional curing processes, ensuring small performance differences in products within batches and greatly improving mass production consistency.

[0049] Thirdly, the energy storage battery box provided in this application is manufactured using the aforementioned highly environmentally adaptable carbon fiber composite material prepared by the above-mentioned method for preparing highly environmentally adaptable carbon fiber composite materials.

[0050] In summary, this application includes at least the following beneficial effects:

[0051] By precisely defining the core components and proportions of carbon fiber reinforcement, silicone rubber binder, and epoxy resin matrix in highly environmentally adaptable carbon fiber composites, a three-phase molecular-level gradient crosslinking system of carbon fiber-fluorosilicone rubber-epoxy resin is constructed. This effectively balances the surface energy differences of each phase, improves interfacial compatibility and bonding strength, and, with the non-competitive synergistic regulation of methylbutynol and vinyl-terminated low-hydrogen-fluorine-content silicone oil, ensures the room temperature service life of the silicone rubber binder and avoids the problems of concentrated exothermic reaction and rapid rate increase during curing.

[0052] By treating carbon fiber cloth with a cold plasma of a mixture of argon, HFO-1234yf and oxygen in a specific ratio, highly active groups are introduced while reducing the oxidative damage to the carbon fiber body. Combined with grafting modification of aminofluorosilane coupling agent, the interfacial bonding performance of carbon fiber reinforcement is further improved.

[0053] By depositing an insulating barrier layer containing cation-modified hydroxylated fluorinated boron nitride nanosheets on the surface of carbon fiber reinforcement, the galvanic corrosion channel between carbon fiber and metal connector is blocked from the source. A nano barrier is also constructed, which improves the material's resistance to media penetration, high temperature resistance and corrosion resistance.

[0054] The HP-RTM three-step gradient pressure injection process is used to impregnate the epoxy resin matrix, which avoids the fluorosilicone rubber layer being damaged by high pressure, while achieving full impregnation and densification of the material and reducing the porosity of the product.

[0055] The four-stage gradient temperature curing process not only shortens the curing cycle and reduces energy consumption, but also effectively eliminates internal stress in the product, avoids defects such as warping and cracking, and ensures the uniformity and dimensional stability of the material curing.

[0056] Applying this composite material to the manufacture of energy storage battery boxes enables them to possess the fundamental advantages of lightweight and high mechanical performance, while also exhibiting excellent environmental adaptability such as resistance to salt spray, high temperature, and galvanic corrosion. This significantly improves the structural reliability and service life of energy storage battery boxes under harsh operating conditions. Furthermore, the entire manufacturing process is adapted to the requirements of wide-range continuous mass production, solving the problem that traditional solutions struggle to balance performance and mass production. Attached Figure Description

[0057] Figure 1 This is a flowchart of the method for preparing the highly environmentally adaptable carbon fiber composite material of this application. Detailed Implementation

[0058] The present application will be further described in detail below with reference to the accompanying drawings.

[0059] This application discloses a highly environmentally adaptable carbon fiber composite material, comprising a carbon fiber reinforcement, a silicone rubber binder, and an epoxy resin matrix.

[0060] The carbon fiber reinforcement comprises, by weight: 100 parts carbon fiber cloth, 3-5 parts aminofluorosilane coupling agent, 0.5-1.5 parts cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.2-0.5 parts BYK-163 dispersant, and 40-60 parts anhydrous ethanol. The carbon fiber cloth is type TD1017, with an areal density of up to 200 g / m². 2 The cationic modified hydroxylated fluorinated boron nitride nanosheets have a diameter of 200-300 nm and a thickness of 2-5 nm.

[0061] The combination of cationic modified hydroxylated fluorinated boron nitride nanosheets with BYK-163 dispersant solves the industry problem of easy agglomeration and sedimentation of traditional nanosheets. It can build a uniform and dense nano-insulating barrier layer on the surface of carbon fiber monofilaments, which has the functions of high temperature resistance, corrosion resistance and galvanic corrosion resistance. It blocks the galvanic corrosion channel between carbon fiber and metal connectors in salt spray environment from the root. The anhydrous ethanol dispersion medium is suitable for continuous production process, ensuring the long-term stability of electrophoresis and impregnation system.

[0062] The overall formulation of carbon fiber reinforcement can achieve multi-level gradient surface modification without damaging the strength of the carbon fiber itself, ensuring a high retention rate of tensile strength of carbon fiber monofilaments. At the same time, it provides a stable active interface for subsequent silicone rubber coating and epoxy resin impregnation, solving the problems of rapid activity decay and poor batch consistency in traditional carbon fiber modification processes.

[0063] The silicone rubber compound, by weight, comprises: 10-12 parts of an epoxy-polyether-fluorosiloxane triblock copolymer, 4-6 parts of a polymethylhydrosiloxane crosslinking agent, 1-2 parts of a caster platinum catalyst, 0.12-0.18 parts of methylbutyninol, 0.08-0.12 parts of a vinyl-terminated low-hydrofluoric acid silicone oil, 1-2 parts of perfluorobutyl glycidyl ether, and 0.3-0.5 parts of a polyether-modified siloxane. The caster platinum catalyst contains 3000 ppm of platinum. Methylbutyninol is a strong coordination-type low-temperature stable retarder, forming a stable 1:1 complex with the platinum catalyst at 25°C, completely inhibiting catalytic activity and ensuring a long room-temperature pot life of the film. Furthermore, it exhibits over 90% irreversible dissociation of catalytic activity within 10 minutes at 65°C, with no residual coordination competition. The vinyl-terminated low-hydrofluoric acid silicone oil is a non-competitive rate regulator, forming a completely synergistic non-competitive system with the main retarder, with no risk of antagonism.

[0064] The epoxy resin matrix comprises, by weight: 10 parts of bisphenol F type epoxy resin, 3-5 parts of phenolic type epoxy resin, 2-3 parts of polyetheramine curing agent D-230, 0.3-0.5 parts of cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.1-0.3 parts of BYK-163 dispersant, 0.1-0.3 parts of silicone defoamer, and 0.2-0.4 parts of BYK-410 rheology modifier.

[0065] This application also discloses a method for preparing a highly environmentally adaptable carbon fiber composite material, which, as shown in the figure, specifically includes the following steps.

[0066] S1. Pre-treat and activate the carbon fiber cloth to obtain carbon fiber reinforcement. The specific steps are as follows.

[0067] S11. Soak the carbon fiber cloth in acetone solution for 2-3 hours, and then vacuum dry it at 50-80℃ for 30-60 minutes to remove the sizing agent and impurities.

[0068] S12. The dried carbon fiber cloth is subjected to cold plasma treatment using a mixture of argon, HFO-1234yf and oxygen.

[0069] The ratio of argon, HFO-1234yf, and oxygen is 90:7:3. The plasma processing power is 250-350W, the pressure is 30-40Pa, the cloth speed is 0.5-1m / min, and the single-sided point processing time is 30-45min.

[0070] S13. The carbon fiber cloth after cold plasma treatment is immersed in an aminofluorosilane coupling agent ethanol solution and ultrasonically impregnated at 50°C for 30 min. Then it is taken out and vacuum dried at 80°C for 30 min to form a monolayer covalently bonded fluorosilane film on the carbon fiber surface, thus obtaining the carbon fiber reinforcement.

[0071] After S1 is completed, an insulating barrier layer is deposited on the carbon fiber reinforcement.

[0072] First, the electrophoresis solution was prepared by adding cationic modified hydroxylated fluorinated boron nitride nanosheets and BYK-163 dispersant to anhydrous ethanol, followed by ultrasonic dispersion at 200W for 30 minutes, and then vacuum degassing for 10 minutes to obtain a stable electrophoresis solution.

[0073] A simplified electrode system consisting of one set of main planar platinum-coated titanium anodes and two sets of edge-compensating platinum-coated titanium anodes was employed, with carbon fiber reinforcement as the working cathode. The electrode spacing was 5 cm, and the carbon fiber reinforcement was completely immersed in the electrophoresis solution. A reusable PTFE pneumatic shielding curtain was used for electric field shielding in the 5 cm edge region of the carbon fiber reinforcement. High-purity nitrogen was continuously circulated in the electrophoresis tank to create an inert protective atmosphere, and an explosion-proof electrical system was installed to reduce the risk of ethanol vapor combustion and explosion. The deposition pulsed DC voltage was 25-30V for the main anode and 18-22V for the edge-compensating anodes, with a pulse duty cycle of 50%, a frequency of 10 Hz, and a deposition time of 15-20 min.

[0074] After deposition, the carbon fiber reinforcement is removed and the surface dust is rinsed with anhydrous ethanol. It is then vacuum dried at 100°C for 20 minutes to form a dense, continuous and uniform cationic modified hydroxylated fluorinated boron nitride nanosheet nano-insulating barrier layer on the surface of the carbon fiber monofilament. This layer blocks the galvanic corrosion channel between the carbon fiber and the metal connector in the salt spray environment from the source and forms the first nano barrier layer to prevent the penetration of corrosive media.

[0075] S2. Prepare a liquid silicone rubber binder. Stir each component of the silicone rubber binder at high speed for 30 minutes at room temperature and then degas under vacuum for 10 minutes to finally obtain the silicone rubber binder.

[0076] S3. The carbon fiber reinforcement is immersed in liquid silicone rubber composite, and after being removed and air-dried, a carbon fiber preform with a fluorosilicone rubber layer on the surface is obtained.

[0077] The carbon fiber reinforcement is impregnated under a vacuum of -0.09 MPa for 3-8 minutes to ensure complete penetration of the silicone rubber composite into the gaps between the carbon fiber monofilaments, forming covalent bonds with the insulating barrier layer and the fluorosilane coupling agent layer. The carbon fiber reinforcement is then removed and air-dried at room temperature. This impregnation and air-drying process is repeated 3-5 times to obtain a carbon fiber reinforcement with a fluorosilicone rubber layer coated on the surface with a thickness of 150-600 μm. The coated carbon fiber reinforcement is then placed in a horizontal laminar flow precision oven and pre-crosslinked at 60°C for 2 hours to allow the fluorosilicone rubber layer to reach the B-stage state, with precise control of the gelation rate at 42%-48%, to obtain the carbon fiber preform.

[0078] S4. Prepare a liquid epoxy resin matrix and impregnate the liquid epoxy resin matrix into the carbon fiber preform to obtain the preform to be cured.

[0079] The epoxy resin matrix components were stirred at high speed for 40 minutes at room temperature, ultrasonically dispersed at 200W for 20 minutes, and vacuum degassed for 15 minutes to complete the preparation. The viscosity of the epoxy resin matrix system was stable at 200-300 mPa•s at 70℃, and the viscosity at 70℃ was maintained at least 180 seconds for a period of time. The carbon fiber preform was placed into an HP-RTM mold and closed with a clamping force of 100-150t. The mold was preheated to a constant temperature of 70℃. The epoxy resin treatment solution was injected into the mold cavity under high pressure using HP-RTM equipment, with the mold temperature controlled at 70℃ throughout the process, and a three-step injection process was performed.

[0080] Phase 1: Low-pressure, low-speed injection. Injection pressure: 2.5 MPa; injection rate: 8 g / s; injection continues until the resin fills 80% of the cavity; injection time: no more than 120 seconds; holding pressure: 30 seconds. Epoxy resin slowly penetrates the surface network of the B-stage fluorosilicone rubber layer under low pressure, forming an interface transition layer to avoid high-pressure erosion and dry pressing. After holding pressure, cross-section verification shows no interface and no white lines are impregnated.

[0081] Second stage: medium-pressure filling transition, injection pressure 5MPa, holding pressure for 20s, allowing epoxy resin to completely fill all corners of the cavity, fully wet the interface between carbon fiber bundles and adhesive layer, and eliminate dead corners and air bubbles in the cavity.

[0082] The third stage: high-pressure densification and compaction, with an injection pressure of 10MPa and a holding pressure of 60s, to completely densify the composite material and ensure that the internal porosity of the product is low.

[0083] S5. A tunnel oven with double-sided infrared radiation and hot air circulation roller conveyor is used to perform a four-stage gradient heating and continuous curing process on the preform to be cured.

[0084] In the first stage, the product is kept at 85℃ for 20 minutes and then gently heated to achieve a smooth temperature rise from the mold temperature of 70℃, thus avoiding thermal shock cracking and achieving uniform temperature throughout the product.

[0085] The second stage: heat preservation at 165℃ for 40 minutes, cross-linking and curing integrated stage, first complete the deep cross-linking of the interface between fluorosilicone rubber and epoxy resin, and then achieve the curing of the epoxy resin body and post-curing to form a stable three-way interpenetrating network structure.

[0086] The third stage: hold at 100℃ for 30 minutes, the first gradient cooling stage, uniform cooling to eliminate internal stress in the product and avoid warping and deformation caused by rapid cooling.

[0087] Fourth stage: Hold at 40℃ for 30 minutes, then proceed to the second gradient cooling stage to reduce the product temperature to room temperature, ensuring dimensional stability after mold opening and preventing deformation caused by internal stress release.

[0088] After curing, trimming, finishing and surface protection treatment are carried out to obtain the final composite material product.

[0089] This application also discloses an energy storage battery box, which is manufactured using the aforementioned high environmental adaptability carbon fiber composite material prepared by the above-described method for preparing high environmental adaptability carbon fiber composite material.

[0090] The following description is based on specific embodiments and comparative examples.

[0091] Example 1:

[0092] A highly environmentally adaptable carbon fiber composite material includes a carbon fiber reinforcement, a silicone rubber binder, and an epoxy resin matrix.

[0093] The carbon fiber reinforcement comprises, by weight: 100 parts carbon fiber cloth, 3 parts aminofluorosilane coupling agent, 0.5 parts cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.2 parts BYK-163 dispersant, and 40 parts anhydrous ethanol.

[0094] The silicone rubber compound comprises, by weight, 10 parts of epoxy-polyether-fluorosiloxane triblock copolymer, 4 parts of polymethylhydrosiloxane crosslinking agent, 1 part of caster platinum catalyst, 0.12 parts of methylbutyninol, 0.08 parts of vinyl-terminated low-hydrofluoric acid silicone oil, 1 part of perfluorobutyl glycidyl ether, and 0.3 parts of polyether-modified siloxane.

[0095] The epoxy resin matrix comprises, by weight: 10 parts of bisphenol F type epoxy resin, 3 parts of phenolic type epoxy resin, 2 parts of polyetheramine curing agent D-230, 0.3 parts of cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.1 parts of BYK-163 dispersant, 0.1 parts of silicone defoamer, and 0.2 parts of BYK-410 rheology modifier.

[0096] A method for preparing a highly environmentally adaptable carbon fiber composite material includes the following steps.

[0097] S1. Pre-treat and activate the carbon fiber cloth to obtain carbon fiber reinforcement. The specific steps are as follows.

[0098] S11. Soak the carbon fiber cloth in acetone solution for 2.5 hours, and then vacuum dry it at 70°C for 40 minutes to remove the sizing agent and impurities.

[0099] S12. The dried carbon fiber cloth is subjected to cold plasma treatment using a mixture of argon, HFO-1234yf and oxygen.

[0100] The ratio of argon, HFO-1234yf, and oxygen is 90:7:3.

[0101] S13. The carbon fiber cloth after cold plasma treatment is immersed in an aminofluorosilane coupling agent ethanol solution and ultrasonically impregnated at 50°C for 30 min. Then it is taken out and vacuum dried at 80°C for 30 min to form a monolayer covalently bonded fluorosilane film on the carbon fiber surface, thus obtaining the carbon fiber reinforcement.

[0102] After S1 is completed, an insulating barrier layer is deposited on the carbon fiber reinforcement.

[0103] After deposition, the carbon fiber reinforcement was removed, the surface dust was rinsed with anhydrous ethanol, and then vacuum dried at 100°C for 20 minutes.

[0104] S2. Prepare a liquid silicone rubber binder. Stir each component of the silicone rubber binder at high speed for 30 minutes at room temperature and then degas under vacuum for 10 minutes to finally obtain the silicone rubber binder.

[0105] S3. The carbon fiber reinforcement is immersed in liquid silicone rubber composite, and after being removed and air-dried, a carbon fiber preform with a fluorosilicone rubber layer on the surface is obtained.

[0106] S4. Prepare a liquid epoxy resin matrix and impregnate the liquid epoxy resin matrix into the carbon fiber preform to obtain the preform to be cured.

[0107] The epoxy resin matrix components were stirred at high speed for 40 minutes at room temperature, ultrasonically dispersed at 200W for 20 minutes, and vacuum degassed for 15 minutes to complete the preparation.

[0108] The carbon fiber preform is placed into an HP-RTM mold and the mold is closed. The mold is preheated to a constant temperature of 70°C. Epoxy resin treatment liquid is injected into the mold cavity under high pressure using HP-RTM equipment. The mold temperature is controlled at 70°C throughout the process, and a three-step injection process is performed.

[0109] First stage: Low-pressure, low-speed injection, injection pressure 2.5MPa, injection rate 8g / s, stop when the resin fills 80% of the cavity, injection time not exceeding 120s, hold pressure for 30s.

[0110] Second stage: medium-pressure filling transition, injection pressure 5MPa, holding pressure for 20s.

[0111] Third stage: High pressure compaction, injection pressure 10MPa, holding pressure for 60s.

[0112] S5. Perform a four-stage gradient heating and continuous curing process on the preform to be cured.

[0113] First stage: keep warm at 85℃ for 20 minutes;

[0114] Second stage: Keep warm at 165℃ for 40 minutes;

[0115] Third stage: Keep warm at 100℃ for 30 minutes;

[0116] Fourth stage: Keep warm at 40℃ for 30 minutes.

[0117] After curing, trimming, finishing and surface protection treatment are carried out to obtain the final composite material product.

[0118] Example 2:

[0119] The difference from Example 1 is that:

[0120] The carbon fiber reinforcement comprises, by weight: 100 parts carbon fiber cloth, 5 parts aminofluorosilane coupling agent, 1.5 parts cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.5 parts BYK-163 dispersant, and 60 parts anhydrous ethanol.

[0121] The silicone rubber compound comprises, by weight, 12 parts of epoxy-polyether-fluorosiloxane triblock copolymer, 6 parts of polymethylhydrosiloxane crosslinking agent, 2 parts of caster platinum catalyst, 0.18 parts of methylbutyninol, 0.12 parts of vinyl-terminated low-hydrofluoric acid silicone oil, 2 parts of perfluorobutyl glycidyl ether, and 0.5 parts of polyether-modified siloxane.

[0122] The epoxy resin matrix comprises, by weight: 10 parts of bisphenol F type epoxy resin, 5 parts of phenolic type epoxy resin, 3 parts of polyetheramine curing agent D-230, 0.5 parts of cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.3 parts of BYK-163 dispersant, 0.3 parts of silicone defoamer, and 0.4 parts of BYK-410 rheology modifier.

[0123] Comparative Example 1:

[0124] The difference from Example 1 is that the silicone rubber compound comprises, by weight, 10 parts of polymethylvinylsiloxane, 6 parts of polymethylhydrosiloxane, and 1 part of a complex of chloroplatinic acid and isopropanol.

[0125] Comparative Example 2:

[0126] The difference from Example 1 is that in step S12 of the method for preparing high environmentally adaptable carbon fiber composite materials, air-cold plasma treatment is used.

[0127] Comparative Example 3:

[0128] The difference from Example 1 is that the deposition of the insulating barrier layer was not performed after step S1 of the method for preparing high environmentally adaptable carbon fiber composite materials.

[0129] Comparative Example 4:

[0130] The difference from Example 1 is that in S4 of the method for preparing high environmentally adaptable carbon fiber composite materials, the impregnation treatment using the HP-RTM process is performed in a one-step injection with an injection pressure of 10 MPa, an injection speed of 8 g / s, and a holding pressure of 80 s.

[0131] Comparative Example 5:

[0132] The difference from Example 1 is that the curing and heating process in S5 of the method for preparing high environmental adaptability carbon fiber composite material is as follows: curing at 80°C for 1.5 hours, then heating to 110°C for 1.5 hours, and then heating to 150°C for 2.5 hours.

[0133] The composite material products obtained from the above examples and comparative examples were tested for the following indicators. Six samples were set up for each indicator test in each example and comparative example.

[0134] Impact resistance testing was conducted according to GB / T 21189-2007 "Test Method for Impact Performance of Simply Supported Beams of Polymer-Based Composite Materials", measuring the unnotched impact strength (kJ / m²) of the simply supported beams. 2 According to the test, the higher the impact strength of a simply supported beam without a notch, the higher its impact resistance.

[0135] For interfacial bonding strength testing, refer to GB / T 35466-2017 "Determination of fiber-matrix interfacial shear strength by single fiber fragment method for fiber-reinforced plastic composites" to test the interfacial shear strength IFSS (MPa). The higher the value, the stronger the interfacial bonding strength between the fiber and the matrix.

[0136] Salt spray resistance test, refer to GB / T 10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test", test and calculate the tensile strength retention rate (%) and IFSS retention rate (%) after salt spray.

[0137] For chemical corrosion resistance testing, refer to GB / T 3857-2017 "Test Method for Chemical Resistance of Glass Fiber Reinforced Thermosetting Plastics" and test the flexural strength retention rate (%) after acid and alkali immersion. The higher the value, the better the chemical corrosion resistance.

[0138] For high-temperature resistance testing, refer to GB / T 35465-2017 "Test Method for Thermal Aging Performance of Polymer-Based Composite Materials" to test the tensile strength retention rate (%) after high-temperature aging.

[0139] Table 1:

[0140]

[0141] Analysis of impact resistance:

[0142] The IFSS and impact strength of Examples 1 and 2 were the best in the group. The core reason is that the fluorosilane coupling agent, triblock copolymer and cationic modified hydroxylated fluorinated boron nitride nanosheets in the formulation constructed a molecular-level gradient crosslinking network of carbon fiber-fluorosilicone rubber-epoxy resin, which not only achieved covalent bonding at the three-phase interface, but also efficiently dissipated impact energy through flexible fluorosilicone segments.

[0143] Comparative Example 1 uses a common polymethylvinylsiloxane system without the gradient compatibility design of triblock copolymers. There is obvious phase separation at the three-phase interface, and the interfacial bonding force drops sharply, making it the sample with the worst basic performance in the whole group.

[0144] Comparative Example 2 uses air-cold plasma to treat carbon fibers, which causes oxidative etching damage to the carbon fiber body, poor stability of active groups, and insufficient interface grafting effect. The IFSS is reduced by 21% compared with Example 1, which verifies the advantages of the low-damage HFO-1234yf fluorination plasma process of this application.

[0145] Comparative Example 4 uses a one-step HP-RTM injection method. The high-pressure fluid directly washes away and destroys the silicone rubber interface layer of the preform. At the same time, the product has high porosity, many interface defects, and a significant reduction in basic properties.

[0146] Comparative Example 5 uses a traditional three-stage curing process, which results in stress concentration and numerous microcracks at the interface during the curing process, also leading to a decline in basic performance.

[0147] Analysis of salt spray resistance:

[0148] In Examples 1 and 2, the tensile strength and IFSS retention rate after salt spray both exceeded 94%, far higher than all comparative examples. The core reason is that the nano-insulating barrier layer not only constructs a labyrinthine dielectric barrier structure, but also blocks the galvanic corrosion channel between the carbon fiber and the metal connector from the root; the gradient cross-linking interface has no microscopic defects, eliminating the penetration path of the salt spray medium; and the fluorosilane-modified carbon fiber surface is hydrophobic and corrosion-resistant, with no interface debonding under long-term salt spray.

[0149] Comparative Example 3 showed the worst salt spray resistance among all samples, with a tensile strength retention rate of only 68.5% and an IFSS retention rate of only 59.6% after salt spraying, a difference of 26.9 percentage points compared to Example 1. This directly verifies that the insulating barrier layer containing cationic modified hydroxylated fluorinated boron nitride nanosheets is the core guarantee of salt spray resistance. Without the barrier layer deposited, galvanic corrosion occurred rapidly in the salt spray environment, with the corrosive medium penetrating along the fiber-matrix interface, causing interfacial debonding and a precipitous decline in performance. The salt spray performance of the other comparative examples also showed significant decline. The core reasons were weak interfacial bonding, high product porosity, and numerous interfacial defects due to uneven curing, leading to rapid penetration of the salt spray medium and damage to the internal structure of the composite material.

[0150] Analysis based on chemical corrosion resistance:

[0151] In Examples 1 and 2, the flexural strength retention rate after acid and alkali immersion both exceeded 93%, demonstrating excellent chemical corrosion resistance. The core reasons are: the introduction of perfluorinated groups and fluorosiloxane segments significantly improved the acid and alkali resistance of the resin system; the global labyrinth barrier structure constructed by cationic modified hydroxylated fluorinated boron nitride nanosheets significantly slowed down the penetration rate of acid and alkali media; and the dense gradient cross-linked interface eliminated phase separation defects caused by media penetration.

[0152] Comparative Examples 1 and 4 exhibited the worst acid and alkali resistance, with retention rates both below 79%. The core issue was the poor compatibility between ordinary silicone rubber and epoxy resin, resulting in a distinct phase interface. Acid and alkali media rapidly penetrated along this interface, causing resin swelling and interface debonding. Furthermore, the high porosity of Comparative Example 4 further accelerated media penetration, leading to the most significant performance degradation. Comparative Examples 2, 3, and 5 still showed a more than 10% difference in acid and alkali resistance compared to the examples. This was primarily due to insufficient surface modification of the carbon fiber, interfacial bonding defects, and the lack of nanoscale barrier structures, which failed to effectively block the penetration and erosion of acid and alkali media.

[0153] Analysis based on high temperature resistance:

[0154] In Examples 1 and 2, the tensile strength retention rate after 180°C heat aging exceeded 92%, which was much higher than all comparative examples. The core advantages stemmed from: the introduction of phenolic epoxy resin, which improved the glass transition temperature and thermo-oxidative stability of the system; the three interpenetrating network structure formed by gradient crosslinking, which prevented interfacial thermal stress concentration and debonding at high temperatures; and the excellent high-temperature resistance of the fluorosiloxane segments themselves, which delayed the thermo-oxidative aging and degradation of the resin matrix.

[0155] Comparative Example 1 exhibited the worst thermal aging performance, with a retention rate of only 78.2%, a decrease of 14.4 percentage points compared to Example 1. The core issue is the weak interfacial bonding between ordinary methyl vinyl silicone rubber and epoxy resin, leading to concentrated interfacial thermal stress at high temperatures and resulting in interfacial debonding. Furthermore, the ordinary bisphenol F epoxy system lacks high-temperature resistance modification, resulting in a rapid rate of thermal and oxidative degradation.

[0156] Comparative Examples 2, 4, and 5 all had thermal aging retention rates below 83%. The main reasons were damage to the carbon fiber itself, high porosity of the product, and large internal stress during curing. Under high temperatures, internal stress was released and interface defects expanded. At the same time, oxygen permeated along the pores, accelerating the thermo-oxidative aging of the resin and causing rapid performance degradation. Comparative Example 3, with undeposited cationic modified hydroxylated fluorinated boron nitride nanosheets, lost the high-temperature reinforcing effect of the nanofiller, and its thermal aging performance also showed a significant decline.

[0157] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A highly environmentally adaptable carbon fiber composite material, comprising a carbon fiber reinforcement, a silicone rubber binder, and an epoxy resin matrix, characterized in that: The silicone rubber composite comprises, by weight, 10-12 parts of an epoxy-polyether-fluorosiloxane triblock copolymer, 4-6 parts of a polymethylhydrosiloxane crosslinking agent, 1-2 parts of a caster platinum catalyst, 0.12-0.18 parts of methylbutyninol, 0.08-0.12 parts of a vinyl-terminated low-hydrofluoric acid silicone oil, 1-2 parts of perfluorobutyl glycidyl ether, and 0.3-0.5 parts of a polyether-modified siloxane.

2. The high environmental adaptability carbon fiber composite material according to claim 1, characterized in that: The carbon fiber reinforcement comprises, by weight: 100 parts carbon fiber cloth and 3-5 parts aminofluorosilane coupling agent.

3. The high environmental adaptability carbon fiber composite material according to claim 1, characterized in that: The epoxy resin matrix comprises, by weight, 10 parts of bisphenol F type epoxy resin, 3-5 parts of phenolic type epoxy resin, 2-3 parts of polyetheramine curing agent D-230, 0.3-0.5 parts of cationic modified hydroxylated fluorinated boron nitride nanosheets, 0.1-0.3 parts of BYK-163 dispersant, 0.1-0.3 parts of silicone defoamer, and 0.2-0.4 parts of BYK-410 rheology modifier.

4. A method for preparing a highly environmentally adaptable carbon fiber composite material, comprising manufacturing the highly environmentally adaptable carbon fiber composite material according to any one of claims 1-3, characterized in that: Specifically, the steps include the following: S1. Pre-treat and activate the carbon fiber cloth to obtain carbon fiber reinforcement; S2. Prepare a liquid silicone rubber bond; S3. The carbon fiber reinforcement is immersed in liquid silicone rubber composite, and after being taken out and air-dried, a carbon fiber preform with a fluorosilicone rubber layer on the surface is obtained. S4. Prepare a liquid epoxy resin matrix and impregnate the liquid epoxy resin matrix into the carbon fiber preform to obtain the preform to be cured. S5. Curing treatment is performed on the preform to be cured.

5. The method for preparing highly environmentally adaptable carbon fiber composite materials according to claim 4, characterized in that: S1 specifically includes the following steps: S11. Soak the carbon fiber cloth in acetone solution and then vacuum dry it to remove the sizing agent and impurities. S12. The dried carbon fiber cloth is subjected to cold plasma treatment using a mixture of argon, HFO-1234yf and oxygen. S13. The carbon fiber cloth treated with cold plasma is immersed in an ethanol solution of aminofluorosilane coupling agent and ultrasonically impregnated, and then vacuum dried to obtain carbon fiber reinforcement.

6. The method for preparing highly environmentally adaptable carbon fiber composite materials according to claim 5, characterized in that: The ratio of argon, HFO-1234yf, and oxygen is 90:7:

3.

7. The method for preparing highly environmentally adaptable carbon fiber composite materials according to claim 4, characterized in that: An insulating barrier layer is deposited on the carbon fiber reinforcement after S1 and before S3. The insulating barrier layer includes cationic modified hydroxylated fluorinated boron nitride nanosheets.

8. The method for preparing highly environmentally adaptable carbon fiber composite materials according to claim 4, characterized in that: The S4 is impregnated using the HP-RTM process, which consists of three injection steps: the first stage, with an injection pressure of 2.5 MPa and an injection rate of 8 g / s, injects the liquid epoxy resin matrix to fill 80% of the mold cavity; the second stage, with an injection pressure of 5 MPa and a holding pressure of 20 s. In the third stage, the injection pressure is 10 MPa, and the pressure is maintained for 60 seconds.

9. The method for preparing highly environmentally adaptable carbon fiber composite materials according to claim 4, characterized in that: The curing process in S5 consists of four stages of temperature rise and curing: the first stage is 85℃ for 20 minutes; the second stage is 165℃ for 40 minutes; the third stage is 100℃ for 30 minutes; and the fourth stage is 40℃ for 30 minutes.

10. An energy storage battery box, characterized in that: The high environmentally adaptable carbon fiber composite material of any one of claims 1-3 is manufactured using the preparation method of the high environmentally adaptable carbon fiber composite material of any one of claims 4-9.

Images