A silicone rubber shell for a high-voltage wiring harness connector for new energy vehicles and its manufacturing method

Abstract

This invention discloses a silicone rubber shell for a high-voltage wiring harness connector in new energy vehicles and its preparation method. The method improves the dispersibility of aluminum nitride filler through surface modification treatment, simultaneously constructing a core-shell composite structure of conductive carbon black and silicon carbide whiskers. The silicone rubber base material is then divided into outer, middle, and inner layers, each incorporating hydrophobic silica, modified aluminum nitride, and core-shell composite particles. These three layers are sequentially injected using a three-barrel injection molding machine, forming a gradient shell structure through directional arrangement and interface treatment. The molded shell is then subjected to staged vulcanization, followed by plasma etching and fluorine-containing coating spraying. Defect detection and compensation are simultaneously performed using X-ray imaging, resulting in a finished shell with multi-layered synergistic functions. This process, through gradient material design and layered molding technology, enables the outer shell to possess excellent hydrophobic and weather-resistant properties, the middle layer to achieve efficient thermal conductivity, and the inner layer to form an electromagnetic shielding network, thereby improving stability and reliability.

Description

Technical Field

[0001] This invention relates to the field of wire harness connectors, and more particularly to a silicone rubber shell for a high-voltage wire harness connector for new energy vehicles and its preparation method. Background Technology

[0002] With the rapid development of new energy vehicles towards high-voltage platforms and fast charging technology, high-voltage wiring harness connectors, as the energy transmission hub between battery packs, motors, and charging systems, face multiple stringent challenges in their working environment, including localized temperature rises exceeding 200°C, 50Hz high-frequency mechanical vibration, and electrolyte corrosion. Silicone rubber shells, due to their high-temperature resistance and good flexibility, have become the mainstream encapsulation material for high-voltage connectors. However, traditional single-structure silicone rubber shells have significant performance bottlenecks when simultaneously meeting the combined requirements of high thermal conductivity, strong electromagnetic shielding, and long-term weather resistance, severely restricting the safety of high-voltage systems and the reliability of the entire vehicle.

[0003] Currently, most high-voltage connector housings are made of silicone rubber materials doped with a single filler (such as alumina to improve thermal conductivity or carbon black to enhance electrical conductivity), manufactured through compression molding. While this approach can specifically improve a particular performance aspect, it suffers from insufficient synergy between the material system and the manufacturing process. For example, adding large amounts of alumina filler to improve thermal conductivity can lead to a surge in material hardness, which can easily cause interface delamination under vibration conditions. On the other hand, when using a carbon black / metal particle composite conductive layer, filler agglomeration causes fluctuations in electromagnetic shielding effectiveness, and microcracks can occur due to CTE mismatch during thermal cycling. Especially in high current density (300A continuous load) scenarios, the heat inside the housing cannot be quickly dissipated through a single functional layer, and localized temperature rise accelerates insulation aging, ultimately leading to a drop in breakdown voltage, which becomes a core pain point restricting the lifespan of high-voltage systems.

[0004] Therefore, it is necessary to improve the housing of the high-voltage connector in the existing technology to solve the technical problems caused by high current temperature rise, electromagnetic interference and complex environment. Summary of the Invention

[0005] The purpose of this invention is to provide a silicone rubber shell for a high-voltage wiring harness connector for new energy vehicles and a method for its preparation, thereby solving the above-mentioned technical problems.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A method for preparing a silicone rubber shell for a high-voltage wiring harness connector for new energy vehicles includes the following steps:

[0008] S1, aluminum nitride filler and silane coupling agent are surface modified, and conductive carbon black and silicon carbide whiskers are combined to form core-shell structured composite particles.

[0009] S2 provides a silicone rubber base material, which is divided into an outer layer, a middle layer and an inner layer. Hydrophobic silica and an anti-aging agent are mixed into the outer layer, surface-modified aluminum nitride filler is dispersed in the middle layer, and the core-shell structure composite particles are uniformly incorporated into the inner layer.

[0010] S3 uses a three-barrel injection molding machine to sequentially inject inner layer rubber, middle layer rubber and outer layer rubber, and forms a molded shell with a gradient structure through directional arrangement control, and performs interface treatment between layers;

[0011] S4, the molded shell is subjected to catalytic vulcanization, high-temperature activation and hot air circulation aging simulation in sequence, and the vulcanization temperature is controlled in the range of 160°C to 200°C for staged vulcanization treatment.

[0012] S5 involves surface etching of the vulcanized shell and spraying a fluorinated siloxane protective coating, while simultaneously implementing defect detection and compensation based on X-ray imaging.

[0013] Optionally, the modification process of the aluminum nitride filler is as follows:

[0014] S11, pretreated aluminum nitride filler, aluminum nitride powder of the first particle size is ultrasonically dispersed in an ethanol-water solution, wherein the volume ratio of ethanol to water is 3:1;

[0015] S12, stepwise coupling agent treatment: silane coupling agent is added dropwise to the ultrasonicated suspension while mechanical stirring is performed simultaneously. After the addition is complete, the temperature is raised to 60℃ and reacted at a constant temperature for 1.5 hours to obtain surface-modified aluminum nitride filler.

[0016] Optionally, the specific process of forming core-shell structured composite particles by combining the conductive carbon black with the silicon carbide whiskers is as follows:

[0017] S13, Conductive carbon black pre-dispersion: Conductive carbon black of the second particle size is added to an isopropanol solution containing polyvinylpyrrolidone and processed at high speed for 20 minutes using a high-speed shear emulsifier to form a stable dispersion.

[0018] S14, place silicon carbide whiskers in a plasma processing device, introduce a mixture of argon and oxygen in a volume ratio of 4:1, and process for 10 minutes at a preset power to activate the surface of the silicon carbide whiskers.

[0019] S15, gradient ball milling composite: the activated silicon carbide whiskers and the stable dispersion are added to the ball milling jar at a mass ratio of 1:3. Zirconia grinding balls are used to perform two-stage ball milling at a preset speed: the first stage is ball milling for 30 minutes to form a physical coating structure, and the second stage is heating to 50°C and adding 0.5wt% polydopamine binder, and continuing ball milling for 60 minutes.

[0020] S16, vacuum drying treatment: the ball-milled mixture is transferred to a vacuum drying oven and dried at 80℃ and -0.1MPa for 4 hours. After airflow pulverization, core-shell structured composite particles are obtained, in which a continuous conductive carbon black coating layer is formed on the surface of silicon carbide whiskers.

[0021] Optionally, step S2 specifically includes the following steps:

[0022] S21, Base material premixing treatment: Methyl vinyl silicone rubber raw rubber and silica are added to a high-speed mixer at a mass ratio of 10:1 and premixed for 15 minutes at 50℃ and 800rpm to form silicone rubber base material;

[0023] S22, functional layer division, distributes silicone rubber base material into three independent mixing systems—outer layer, middle layer, and inner layer—in a mass ratio of 3:4:3.

[0024] Optionally, after step S22, the method further includes:

[0025] S23, 2wt% hydrophobic nano silica and 0.8wt% carbon nanotube composite anti-aging agent are added to the outer layer rubber compound system, and the mixture is mixed in an internal mixer at 40℃ and 60rpm for 8min to obtain the outer layer rubber compound.

[0026] S24, 25wt% of surface-modified aluminum nitride filler is added to the intermediate layer rubber compound system, and a two-stage intensive mixing process is adopted: the first stage is low-speed dispersion at 50℃ and 40rpm for 5min, and the second stage is high-speed mixing at 70℃ and 90rpm for 10min to obtain the intermediate layer rubber compound.

[0027] S25 involves adding 15wt% core-shell composite particles and 0.5wt% chopped carbon fiber filaments to the inner layer rubber compound system, and performing dynamic vulcanization treatment in a twin-screw extruder, controlling the barrel temperature at 80-100℃ and the screw speed at 120rpm to obtain the inner layer rubber compound.

[0028] Optionally, step S3 specifically includes the following steps:

[0029] S31, Mold gradient preheating, the molding mold of the three-barrel injection molding machine is divided into zones for temperature control: the inner molding zone is heated to 120℃, the middle molding zone is kept at 110℃, and the outer molding zone is set to 100℃, with a preheating time of 30±2min.

[0030] S32, layered sequential injection, the inner layer rubber, the middle layer rubber and the outer layer rubber are injected sequentially through an independent barrel, and the injection pressure is controlled to be 80MPa, 100MPa and 60MPa respectively. When the inner layer rubber is injected, the screw speed is the first speed, the middle layer is increased to the second speed, and the outer layer is reduced to the third speed.

[0031] S33, during the layered sequential injection process, after each layer is injected, a 3:1 volume ratio argon / nitrogen mixed plasma is sprayed onto the molding surface through a plasma nozzle with a power of 600W and a processing time of 20s to implement interlayer interface treatment.

[0032] S34, gradient cooling and shaping, after injection, the pressure is held in stages: the first stage is held at 50MPa and the temperature is maintained at 100℃ for 2 minutes, the second stage is reduced to 30MPa and gradient cooled to 60℃, and after demolding, a molded shell with a three-dimensional oriented gradient structure is obtained.

[0033] Optionally, step S4 specifically includes the following steps:

[0034] S41, pre-vulcanization catalytic treatment: the molded shell is placed in a closed vulcanization chamber containing 0.5wt% platinum catalyst, nitrogen gas is introduced to protect the environment, the temperature is raised to 160℃ at a rate of 10℃ / min and held at the temperature for 20min to trigger the initial cross-linking of silicone rubber.

[0035] S42, the sealed vulcanization chamber is heated by gradient temperature increase, and the temperature is increased in multiple stages, while step pressure is applied simultaneously during the vulcanization process;

[0036] S43, the vulcanized shell is placed in a forced convection oven, and the temperature is circulated and raised at a rate of 200℃ / h with high temperature air at 200℃. Each temperature zone is maintained for 30 minutes, and n complete cycles are completed to simulate hot air circulation aging.

[0037] S44 was slowly cooled to room temperature under a constant temperature of 80℃ and a negative pressure environment of 0.1MPa, and the cooling rate was controlled to obtain a dimensionally stable vulcanized shell.

[0038] Optionally, step S42 specifically includes:

[0039] The temperature was increased in three stages. In the first stage, the temperature was increased to 180℃ at 5℃ / min and treated for 30min to complete the main crosslinking. In the second stage, the temperature was increased to 190℃ at 3℃ / min and treated for 20min to optimize the density. In the third stage, the temperature was increased to 200℃ at 2℃ / min and treated for 10min to eliminate internal stress.

[0040] The step pressure application process is as follows: maintain 0.5MPa at 160℃, increase to 1.2MPa at 180℃, and decrease to 0.8MPa at 200℃.

[0041] Optionally, step S5 specifically includes the following steps:

[0042] S51, the sulfurized shell is placed in a vacuum chamber and argon / carbon tetrafluoride mixed gas is introduced. It is then subjected to 30s pulsed plasma treatment at 800W radio frequency power to form a rough surface.

[0043] S52, a protective coating is formed by sequentially spraying a base layer of first thickness and a top layer of second thickness using a two-component electrostatic spray gun, controlling the spraying distance at 200mm, the voltage at 50kV, and the curing interval between layers at 5min; the base layer is a fluorosiloxane binder, and the top layer is a nano-ceramic protective slurry;

[0044] S53 uses a micro-focus X-ray imaging system to perform three-dimensional scanning of the protective coating and identifies defective areas with porosity or thickness deviation in real time based on an intelligent recognition algorithm.

[0045] S54, a compensation slurry is sprayed onto the identified defective area using laser-assisted positioning technology, and after local reinforcement, it is cured a second time to form a continuous protective layer; the compensation slurry includes fluorinated siloxane and silicon carbide nanosheets.

[0046] This invention also provides a silicone rubber shell for a high-voltage wiring harness connector for new energy vehicles, which is prepared using the method described above. The silicone rubber shell specifically comprises:

[0047] The layers, arranged sequentially from the outside in, are a hydrophobic and weather-resistant layer, a directional thermally conductive layer, and a conductive shielding layer, wherein:

[0048] The hydrophobic weather-resistant layer comprises hydrophobic nano-silica and a gradient cross-linked structure;

[0049] The directional heat-conducting layer has aluminum nitride filler arranged in a directional manner along the heat flow direction;

[0050] The conductive shielding layer forms a conductive network of silicon carbide whiskers and conductive carbon black core-shell particles.

[0051] The surface of the silicone rubber shell is provided with a composite protective layer containing fluorinated siloxane and nano-ceramics.

[0052] Compared with existing technologies, this invention has the following advantages: First, surface modification treatment improves the dispersibility of aluminum nitride filler, simultaneously constructing a core-shell composite structure of conductive carbon black and silicon carbide whiskers; then, the silicone rubber base material is divided into outer, middle, and inner layers, with hydrophobic silica, modified aluminum nitride, and core-shell composite particles added respectively to achieve directional distribution of functional components; next, a three-barrel injection molding machine is used to sequentially inject the three layers of material, forming a gradient structure shell through directional arrangement and interface treatment; then, the molded shell undergoes staged vulcanization treatment, sequentially completing crosslinking catalysis, high-temperature activation, and aging resistance strengthening; finally, surface functional strengthening is achieved through plasma etching and fluorine-containing coating spraying, and defect detection and compensation are simultaneously completed based on X-ray imaging, resulting in a finished shell product with multi-layer synergistic functions; this process, through gradient material design and layered molding technology, enables the outer shell to have excellent hydrophobic weather resistance, the middle layer to achieve efficient thermal conductivity, and the inner layer to form an electromagnetic shielding network. The staged vulcanization process combined with temperature step control improves structural stability, and with real-time X-ray detection technology, product reliability is significantly improved. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0055] Figure 1 This is one of the flowcharts illustrating the preparation method of the silicone rubber shell for the high-voltage wiring harness connector of a new energy vehicle according to Embodiment 1.

[0056] Figure 2 This is the second schematic diagram of the process for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles in this embodiment one;

[0057] Figure 3 This is a half-sectional schematic diagram of the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles in this embodiment 2. Detailed Implementation

[0058] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0060] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0061] Example 1:

[0062] Combination Figures 1 to 2 As shown in the figure, this invention provides a method for preparing a silicone rubber shell for a high-voltage wiring harness connector in a new energy vehicle, comprising the following steps:

[0063] S1, aluminum nitride filler and silane coupling agent are surface modified, and conductive carbon black and silicon carbide whiskers are combined to form core-shell structured composite particles.

[0064] Surface modification of aluminum nitride filler using silane coupling agents allows for the formation of chemically bonded graft layers on the filler surface through hydrolysis, thereby enhancing the interfacial bonding between the filler and the silicone rubber matrix while reducing agglomeration. The composite of conductive carbon black and silicon carbide whiskers employs a physical-chemical combination strategy, forming core-shell structured composite particles through whisker surface activation and carbon black coating, aiming to construct a highly conductive network while maintaining mechanical reinforcement.

[0065] S2 provides a silicone rubber base material, which is divided into an outer layer, a middle layer, and an inner layer. Hydrophobic silica and an anti-aging agent are mixed into the outer layer, surface-modified aluminum nitride filler is dispersed in the middle layer, and core-shell structured composite particles are uniformly incorporated into the inner layer. The layered mixing process ensures that the fillers in each layer are evenly distributed and functionally independent.

[0066] Functional zoning design based on silicone rubber base material: the outer layer of rubber material introduces hydrophobic silica to improve weather resistance by utilizing its low surface energy properties; the addition of anti-aging agents delays material oxidation; the middle layer of rubber material forms a thermally conductive path by dispersing modified aluminum nitride filler to optimize heat conduction efficiency; the inner layer of rubber material incorporates core-shell composite particles, utilizing the mechanical support of silicon carbide whiskers and the conductivity of conductive carbon black to achieve electromagnetic shielding function.

[0067] S3 uses a three-barrel injection molding machine to sequentially inject inner layer rubber, middle layer rubber and outer layer rubber, and forms a molded shell with a gradient structure through directional arrangement control, and performs interface treatment between layers;

[0068] A three-barrel injection molding machine is used to inject the inner layer → middle layer → outer layer in sequence. By differentially controlling the screw speed and injection pressure (high speed and high pressure for the inner layer, and low speed and low pressure for the outer layer), the filler is directionally arranged in a specific direction, forming a conductive-thermal-protective gradient structure from the inside out. Interlayer interface treatment (such as plasma treatment) enhances the interlayer bonding strength through surface chemical activation, preventing interface delamination.

[0069] S4, the molded shell is subjected to catalytic vulcanization, high-temperature activation and hot air circulation aging simulation in sequence, and the vulcanization temperature is controlled in stages between 160℃ and 200℃.

[0070] Temperature control is implemented in stages during the vulcanization process:

[0071] The catalytic vulcanization stage (160℃) triggers the cross-linking of the silicone rubber backbone, forming a basic network structure;

[0072] The high-temperature activation stage (200℃) promotes the reaction of residual double bonds and increases the cross-linking density;

[0073] Hot air cycling aging simulation accelerates the release of internal stress and verifies the material's thermal fatigue resistance through temperature shock. The segmented vulcanization strategy balances crosslinking efficiency and material stability.

[0074] S5 involves surface etching of the vulcanized shell and spraying a fluorinated siloxane protective coating, while simultaneously implementing defect detection and compensation based on X-ray imaging.

[0075] Surface etching creates a micron-level rough surface through plasma bombardment, increasing coating adhesion; fluorinated siloxane protective coatings provide hydrophobicity and chemical corrosion resistance; X-ray imaging detection identifies internal pores or uneven thickness defects through three-dimensional scanning, and locates and sprays compensating slurry based on the detection results to ensure the continuity and reliability of the protective layer.

[0076] The working principle of this invention is as follows: First, the dispersibility of aluminum nitride filler is improved through surface modification treatment, and a core-shell composite structure of conductive carbon black and silicon carbide whiskers is constructed simultaneously. Then, the silicone rubber base material is divided into outer, middle and inner layers, and hydrophobic silica, modified aluminum nitride and core-shell composite particles are added respectively to achieve directional distribution of functional components. Next, the three layers of rubber are injected sequentially using a three-barrel injection molding machine, and a gradient structure shell is formed through directional arrangement and interface treatment. Then, the molded shell is subjected to staged vulcanization treatment, and cross-linking catalysis, high-temperature activation and aging resistance strengthening are completed sequentially. Then, surface functional strengthening is achieved through plasma etching and fluorine-containing coating spraying, and defect detection and compensation are completed simultaneously based on X-ray imaging to obtain a shell product with multi-layer synergistic functions. This process, through gradient material design and layered molding technology, enables the outer layer of the shell to have excellent hydrophobic weather resistance, the middle layer to achieve efficient thermal conductivity, and the inner layer to form an electromagnetic shielding network. The staged vulcanization process combined with temperature step control improves structural stability, and with the help of X-ray real-time detection technology, the reliability of the product is significantly improved.

[0077] In this embodiment, the modification process of the aluminum nitride filler is specifically described as follows:

[0078] S11, Pretreated aluminum nitride filler: Aluminum nitride powder with a first particle size D50=3-5μm is placed in an ethanol aqueous solution and ultrasonically dispersed, wherein the volume ratio of ethanol to water is 3:1, the ultrasonic power is 500W, and the treatment time is 30±2min.

[0079] Aluminum nitride powder was ultrasonically dispersed using an ethanol-water solution (3:1 volume ratio). The organic solvent properties of ethanol reduced the surface energy of the filler, while the addition of water promoted the subsequent hydrolysis of the silane coupling agent. The 3:1 volume ratio solution combined dispersion efficiency with reaction compatibility: the high ethanol content facilitated the wetting of the hydrophobic filler, while the appropriate amount of water provided the necessary environment for the hydrolysis of the coupling agent. Ultrasonic treatment disrupted filler agglomeration through cavitation, ensuring uniform dispersion for subsequent surface modification.

[0080] S12, stepwise coupling agent treatment: silane coupling agent is added dropwise to the sonicated suspension, with the dropping rate controlled at 2 mL / min, and mechanical stirring is performed simultaneously at 200 rpm. After the addition is completed, the temperature is raised to 60℃ and reacted at a constant temperature for 1.5 h to obtain surface-modified aluminum nitride filler.

[0081] Adding the silane coupling agent dropwise while mechanically stirring avoids flocculation caused by excessively high local concentrations, ensuring that the coupling agent molecules are uniformly anchored on the aluminum nitride surface. Heating the reaction to 60°C accelerates the hydrolysis and condensation process of the coupling agent, allowing the silanol groups to form stable chemical bonds with the filler surface. This parameter design balances the reaction rate and controls side reactions, ultimately yielding a modified filler with uniform surface grafting, significantly improving its interfacial bonding strength with the silicone rubber matrix.

[0082] S13, Conductive carbon black pre-dispersion: Conductive carbon black of the second particle size is added to an isopropanol solution containing polyvinylpyrrolidone and processed at high speed for 20 minutes using a high-speed shear emulsifier to form a stable dispersion.

[0083] Polyvinylpyrrolidone (PVP) is adsorbed onto the surface of conductive carbon black as a dispersant, inhibiting agglomeration through steric hindrance. The low surface tension of the isopropanol solution further enhances the dispersion effect. High-speed shear emulsification (high rotation speed) provides sufficient mechanical energy input to break up secondary agglomerates of carbon black, forming a stable nanoscale dispersion. This process design ensures that the conductive carbon black maintains high dispersion during subsequent compounding, laying the foundation for building a continuous conductive network.

[0084] S14. Silicon carbide whiskers with a diameter of 0.5-1μm and an aspect ratio of 20:1 are placed in a plasma processing device, and a mixture of argon and oxygen with a volume ratio of 4:1 is introduced. The mixture is processed for 10 minutes at a preset power to activate the surface of the silicon carbide whiskers.

[0085] Plasma treatment with a 4:1 volume ratio of argon and oxygen cleans the whisker surface and increases the specific surface area by bombarding it with argon ions, while oxygen introduces oxygen-containing polar groups to enhance its bonding ability with conductive carbon black. The 4:1 volume ratio design balances the dual requirements of physical etching and chemical modification: argon-dominated physical activation improves surface roughness, while an appropriate amount of oxygen promotes chemical bonding, providing an active interface for subsequent core-shell structure composites.

[0086] S15, gradient ball milling composite: activated silicon carbide whiskers and stable dispersion are added to a ball mill jar at a mass ratio of 1:3. Zirconia grinding balls are used to perform two-stage ball milling at a preset speed: the first stage is ball milling for 30 minutes to form a physical coating structure, and the second stage is heating to 50°C and adding 0.5wt% polydopamine binder, and continuing ball milling for 60 minutes.

[0087] A two-stage ball milling strategy: The first stage uses mechanical force to physically coat the silicon carbide whisker surface with carbon black; the second stage adds a polydopamine binder and ball mills at 50°C, utilizing its biomimetic adhesion properties to strengthen interfacial bonding. The high hardness of the zirconia grinding balls avoids grinding contamination, and the preset rotation speed ensures controllable ball milling energy input, synergistically constructing a stable core-shell structure and significantly improving the mechanical stability and electrical continuity of the conductive network.

[0088] S16, vacuum drying treatment: the ball-milled mixture is transferred to a vacuum drying oven and dried at 80℃ and -0.1MPa for 4 hours. After airflow pulverization, core-shell structured composite particles are obtained, in which a continuous conductive carbon black coating layer is formed on the surface of silicon carbide whiskers.

[0089] Vacuum drying at 80℃ (-0.1MPa) slowly removes the solvent under low temperature and low pressure, avoiding carbon black oxidation or whisker structure damage caused by high temperature. Airflow milling achieves particle size homogenization of the composite particles through high-speed airflow collision while preserving the integrity of the core-shell structure. This combination of parameters maximizes the preservation of material functional properties while ensuring drying efficiency, resulting in uniformly dispersed, interface-stable core-shell composite particles.

[0090] In this embodiment, step S2 specifically includes the following steps:

[0091] S21, Base material premixing treatment: Methyl vinyl silicone rubber raw rubber and silica are added to a high-speed mixer at a mass ratio of 10:1 and premixed for 15 minutes at 50℃ and 800rpm to form silicone rubber base material;

[0092] The aim was to construct a homogeneous silicone rubber base system by mixing methyl vinyl silicone rubber raw rubber and silica at a mass ratio of 10:1 and premixing at 50°C and 800 rpm for 15 min. Silica, as a reinforcing filler, improves the mechanical properties of the matrix, and the 10:1 mass ratio balances flowability requirements with reinforcing effects. The mixing temperature of 50°C prevents premature crosslinking of the raw rubber while promoting silica dispersion; the rotation speed of 800 rpm provides sufficient shear force to break filler agglomeration, ensuring the homogeneity of the premixed compound and providing a stable foundation for subsequent layered modification.

[0093] S22, functional layer division, distributes silicone rubber base material into three independent mixing systems—outer layer, middle layer, and inner layer—in a mass ratio of 3:4:3.

[0094] The base material is distributed in a 3:4:3 mass ratio to the outer, middle, and inner layers of the rubber compound. This ratio is designed based on the performance requirements of each functional layer: the middle layer needs to support a high proportion of thermally conductive fillers, so more base material is allocated to maintain processing fluidity; the amounts of the outer and inner layers are matched to the amount of their functional fillers. The layered independent mixing system avoids mutual interference between different functional fillers and ensures the specificity of the material properties of each layer.

[0095] S23, 2wt% hydrophobic nano silica and 0.8wt% carbon nanotube composite anti-aging agent are added to the outer layer rubber compound system, and the mixture is mixed in an internal mixer at 40℃ and 60rpm for 8min to obtain the outer layer rubber compound.

[0096] A composite anti-aging agent consisting of 2 wt% hydrophobic nano-silica and 0.8 wt% carbon nanotubes was added to the outer layer of the rubber compound, and the mixture was internally mixed for 8 minutes at 40°C and 60 rpm. The low-temperature mixing at 40°C reduces the risk of thermal decomposition of the anti-aging agent, while the 60 rpm speed matches the low shear sensitivity of the hydrophobic filler, avoiding damage to its surface modification layer. The synergistic effect of carbon nanotubes and hydrophobic fillers enhances the outer layer's resistance to UV aging, while the closed environment of the internal mixing process inhibits moisture intrusion, ensuring material stability.

[0097] S24, 25wt% of surface-modified aluminum nitride filler is added to the intermediate layer rubber compound system, and a two-stage intensive mixing process is adopted: the first stage is low-speed dispersion at 50℃ and 40rpm for 5min, and the second stage is high-speed mixing at 70℃ and 90rpm for 10min to obtain the intermediate layer rubber compound.

[0098] A two-stage internal mixing process (50℃ / 40rpm → 70℃ / 90rpm) is designed to address the dispersion characteristics of modified aluminum nitride fillers: the first stage, with its low temperature and low speed, promotes initial wetting and dispersion of the filler, preventing the surface modification layer from peeling off due to high-speed shearing; the second stage raises the temperature to 70℃ and increases the rotation speed, utilizing the reduced viscosity of the silicone rubber matrix to accelerate the directional arrangement of the filler, forming a continuous thermally conductive path. This segmented process optimizes the processing window for highly filled systems, balancing dispersion efficiency and structural integrity.

[0099] S25 involves adding 15wt% core-shell composite particles and 0.5wt% chopped carbon fiber filaments to the inner layer rubber compound system, and performing dynamic vulcanization treatment in a twin-screw extruder, controlling the barrel temperature at 80-100℃ and the screw speed at 120rpm to obtain the inner layer rubber compound.

[0100] 15wt% core-shell composite particles and 0.5wt% chopped carbon fiber filaments were added to the inner layer compound, and dynamic vulcanization was carried out using a twin-screw extruder (80-100℃, 120rpm). Dynamic vulcanization, through the synergistic effect of mechanical shear and heat, promotes pre-crosslinking of part of the silicone rubber matrix, forming an "island structure," thereby improving the fixation effect of the conductive filler. The addition of chopped carbon fiber filaments enhances the tear resistance of the inner layer, while the barrel temperature range of 80-100℃ avoids thermal degradation of the material and ensures sufficient dynamic vulcanization reaction. The 120rpm screw speed matches the dispersion requirements of the conductive filler, preventing excessive fiber breakage.

[0101] In this embodiment, step S3 specifically includes the following steps:

[0102] S31, Mold gradient preheating, the molding mold of the three-barrel injection molding machine is divided into zones for temperature control: the inner molding zone is heated to 120℃, the middle molding zone is kept at 110℃, and the outer molding zone is set to 100℃, with a preheating time of 30±2min.

[0103] By controlling the temperature of the injection mold in zones (inner layer 120℃, middle layer 110℃, outer layer 100℃), the rheological properties of each layer of the rubber compound are matched: the high temperature of the inner layer (120℃) reduces the viscosity of the conductive rubber compound to promote the filling of complex structures; the medium temperature of the middle layer (110℃) maintains the directional distribution ability of the thermally conductive filler; and the low temperature of the outer layer (100℃) avoids the thermal decomposition of the hydrophobic agent. A preheating time of 30±2 minutes ensures that the temperature of each area of ​​the mold is uniform and stable, eliminating problems such as uneven shrinkage or interface stress concentration caused by temperature differences.

[0104] S32, layered sequential injection, the inner layer rubber, the middle layer rubber and the outer layer rubber are injected sequentially through an independent barrel, the injection pressure is controlled to be 80MPa, 100MPa and 60MPa respectively, the injection interval is 15s, the screw speed is the first speed of 40rpm when the inner layer rubber is injected, the middle layer is increased to the second speed of 55rpm, and the outer layer is reduced to the third speed of 30rpm.

[0105] Differential injection parameter design (inner layer 80MPa / 40rpm, middle layer 100MPa / 55rpm, outer layer 60MPa / 30rpm) based on functional layer characteristics:

[0106] The inner high voltage and high speed (80MPa / 40rpm) ensure the uniform distribution of conductive composite particles at a high filling rate (15wt%).

[0107] The intermediate layer's ultra-high pressure (100MPa) combined with accelerated speed (55rpm) forces the aluminum nitride packing to be oriented along the heat flow direction;

[0108] The outer layer operates at low pressure and low speed (60MPa / 30rpm) to reduce shear damage to hydrophobic nanoparticles.

[0109] The 15-second injection interval allows the preceding rubber compound to cool and set properly, preventing interlayer melt penetration that could lead to functional mixing.

[0110] S33, during the layered sequential injection process, after each layer is injected, a 3:1 volume ratio argon / nitrogen mixed plasma is sprayed onto the molding surface through a plasma nozzle with a power of 600W and a processing time of 20s to implement interlayer interface treatment.

[0111] Argon / nitrogen mixed plasma (3:1 volume ratio) treatment cleans the interface and increases the specific surface area through physical bombardment of argon ions, while nitrogen free radical chemical grafting forms nitrogen-containing polar groups at the interface, enhancing interlayer chemical bonding. The 600W power and 20s treatment time balance the surface activation depth and the risk of material thermal damage, achieving optimization of interfacial bonding strength and production efficiency.

[0112] S34, gradient cooling and shaping, after injection, the pressure is held in stages: the first stage is held at 50MPa and the temperature is maintained at 100℃ for 2 minutes, the second stage is reduced to 30MPa and gradient cooled to 60℃, and after demolding, a molded shell with a three-dimensional oriented gradient structure is obtained.

[0113] Phased pressure holding and cooling strategy:

[0114] The first stage of high-temperature pressure holding (100℃×2min / 50MPa) utilizes the thermoelastic effect of silicone rubber to promote molecular chain relaxation and eliminate residual injection stress.

[0115] The second stage of gradient cooling (100℃→60℃) involves slowly releasing pressure (50→30MPa) to reduce temperature synchronously, thus suppressing warping deformation caused by sudden cooling.

[0116] This combination of parameters enables a stable three-dimensional oriented arrangement structure inside the shell, while ensuring dimensional accuracy.

[0117] In this embodiment, step S4 specifically includes the following steps:

[0118] S41, pre-vulcanization catalytic treatment: the molded shell is placed in a closed vulcanization chamber containing 0.5wt% platinum catalyst, nitrogen gas is introduced to protect the environment, the temperature is raised to 160℃ at a rate of 10℃ / min and held at the temperature for 20min to trigger the initial cross-linking of silicone rubber.

[0119] This step employs a nitrogen-protected environment containing 0.5 wt% platinum catalyst, with the temperature increased to 160°C at a rate of 10°C / min and held at that temperature for 20 min to trigger the initial crosslinking of the silicone rubber. The platinum catalyst efficiently catalyzes the hydrosilylation reaction in the inert nitrogen atmosphere, forming the initial crosslinked network. The 10°C / min heating rate avoids uneven crosslinking caused by localized overheating, and the 20-min holding at 160°C ensures a pre-cured state with a crosslinking degree of 15-20%, providing structural support for subsequent main crosslinking. Nitrogen protection effectively suppresses high-temperature oxidation side reactions, maintaining the material's electrical insulation properties.

[0120] S42 involves gradient temperature vulcanization in a closed vulcanization chamber, with multi-stage heating and simultaneous application of stepped pressure during the vulcanization process; specifically including:

[0121] The temperature was increased in three stages. In the first stage, the temperature was increased to 180℃ at 5℃ / min and treated for 30min to complete the main crosslinking. In the second stage, the temperature was increased to 190℃ at 3℃ / min and treated for 20min to optimize the density. In the third stage, the temperature was increased to 200℃ at 2℃ / min and treated for 10min to eliminate internal stress.

[0122] The main crosslinking stage at 180℃ (heating at 5℃ / min) achieves full crosslinking of the silicone rubber backbone, constructing a three-dimensional network framework;

[0123] The densification stage at 190℃ (heating at 3℃ / min) eliminates micropores and increases the density of the material through molecular chain rearrangement;

[0124] The 200℃ stress release stage (heating at 2℃ / min) promotes the relaxation of residual stress and avoids later deformation.

[0125] The process of applying stepped pressure is as follows: 0.5 MPa is maintained at 160℃, increased to 1.2 MPa at 180℃, and decreased to 0.8 MPa at 200℃. Synchronous stepped pressure control (0.5 MPa → 1.2 MPa → 0.8 MPa) works in conjunction with the temperature gradient: the high-pressure stage (1.2 MPa) compresses air bubbles and promotes packing orientation, while the low-pressure stage (0.8 MPa) alleviates shrinkage stress, creating a synergistic effect of "high-pressure compaction - low-pressure shaping".

[0126] S43, the vulcanized shell is placed in a forced convection oven, and the temperature is circulated and raised at a rate of 200℃ / h with high temperature air at 200℃. Each temperature zone is maintained for 30 minutes, and n complete cycles are completed to simulate hot air circulation aging.

[0127] High-temperature air at 200℃ is circulated at a rate of 20℃ / h, with each temperature zone maintained for 30 minutes, simulating equivalent thermal fatigue through circulation. A forced convection oven ensures temperature uniformity, and the 20℃ / h heating and cooling rate matches the material's thermal relaxation characteristics, preventing microcracks caused by thermal shock.

[0128] S44 was slowly cooled to room temperature under a constant temperature of 80℃ and a negative pressure environment of 0.1MPa, and the cooling rate was controlled to obtain a dimensionally stable vulcanized shell.

[0129] The material is slowly cooled at a rate of ≤2℃ / min under a constant temperature of 80℃ and a negative pressure of 0.1MPa. The negative pressure environment suppresses the formation of residual bubbles of volatile substances during the cooling process. The slow cooling rate matches the glass transition temperature range of silicone rubber (-50℃~80℃) to avoid molecular chain freezing stress caused by sudden temperature drop.

[0130] In this embodiment, step S5 specifically includes the following steps:

[0131] S51, the sulfurized shell is placed in a vacuum chamber and argon / carbon tetrafluoride mixed gas is introduced. It is then subjected to 30s pulsed plasma treatment at 800W radio frequency power to form a rough surface.

[0132] The surface of the sulfurized shell is subjected to dual modification in a vacuum chamber by pulsed plasma treatment with a mixture of argon and carbon tetrafluoride (800W / 30s): physical treatment with argon ions forms a micron-level rough surface (Ra=2-5μm), and chemical grafting of fluorine radicals generated by the decomposition of carbon tetrafluoride forms CF bonds, giving the surface hydrophobicity and chemical corrosion resistance.

[0133] S52 uses a two-component electrostatic spray gun to sequentially spray a base layer of the first thickness and a top layer of the second thickness to form a protective coating. The spraying distance is controlled at 200mm, the voltage at 50kV, and the curing interval between layers is 5min. The base layer is a fluorosiloxane binder, and the top layer is a nano-ceramic protective slurry.

[0134] A two-component electrostatic spray gun is used to sequentially apply a base coat (fluorosiloxane binder, 10-15 μm thick) and a top coat (nano-ceramic slurry, 35-40 μm thick). Uniform coating deposition is achieved through a 200 mm spraying distance and 50 kV high-voltage electrostatic adsorption. The polymer chains of the fluorosiloxane base coat penetrate into the micropores of the rough surface to form a mechanical interlock, while the nano-ceramic top coat provides wear resistance and temperature resistance protection.

[0135] S53 uses a micro-focus X-ray imaging system to perform three-dimensional scanning of the protective coating and identifies defective areas with porosity or thickness deviation in real time based on intelligent recognition algorithm convolutional neural network.

[0136] A microfocus X-ray imaging system (10 μm resolution) performs 3D scanning of the coating, and analyzes porosity (threshold > 0.5%) and thickness deviation (> 8%) in real time based on a convolutional neural network (CNN) algorithm. The CNN model achieves high-precision classification through transfer learning pre-training, and combines morphological operations to locate defect coordinates. This parameter combination improves the detection rate of microcracks / bubbles to an engineering-applicable level, while reducing the inspection time per part to within 3 minutes, meeting the requirements of mass production cycle time.

[0137] S54. Laser-assisted positioning technology is used to spray compensation slurry on the identified defective areas. After local reinforcement, secondary curing is performed to form a continuous protective layer. The compensation slurry includes fluorinated siloxane and silicon carbide nanosheets.

[0138] For the identified defective areas, a compensating slurry (containing fluorosiloxane + 20wt% silicon carbide nanosheets) was sprayed using laser-guided positioning. The layer-by-layer stacking effect of silicon carbide blocked the defect propagation path. Secondary curing promoted the formation of chemical bonds between the compensating slurry and the substrate coating, and the hardness and wear resistance of the local area were improved to more than 90% of the surface layer index.

[0139] Example 2:

[0140] Combination Figure 3As shown in the figure, which is a half-sectional view of the silicone rubber shell, the present invention also provides a silicone rubber shell for a high-voltage wiring harness connector for new energy vehicles, which is prepared by the method for preparing a silicone rubber shell for a high-voltage wiring harness connector for new energy vehicles as described in Example 1. The silicone rubber shell specifically includes:

[0141] The layers, arranged sequentially from the outside in, are a hydrophobic and weather-resistant layer 10, a directional thermally conductive layer 20, and a conductive shielding layer 30, wherein:

[0142] The hydrophobic weather-resistant layer 10 comprises hydrophobic nano-silica and a gradient cross-linked structure;

[0143] The directional heat-conducting layer 20 has aluminum nitride filler arranged in a direction along the heat flow direction;

[0144] The conductive shielding layer 30 is formed with a conductive network of silicon carbide whiskers and conductive carbon black core-shell particles.

[0145] The surface of the silicone rubber shell is provided with a composite protective layer 40 containing fluorinated siloxane and nano-ceramics.

[0146] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a silicone rubber shell for a high-voltage wiring harness connector in a new energy vehicle, characterized in that, Includes the following steps: S1, aluminum nitride filler and silane coupling agent are surface modified, and conductive carbon black and silicon carbide whiskers are combined to form core-shell structured composite particles. S2 provides a silicone rubber base material, which is divided into an outer layer, a middle layer and an inner layer. Hydrophobic silica and an anti-aging agent are mixed into the outer layer, surface-modified aluminum nitride filler is dispersed in the middle layer, and the core-shell structure composite particles are uniformly incorporated into the inner layer. S3 uses a three-barrel injection molding machine to sequentially inject inner layer rubber, middle layer rubber and outer layer rubber, and forms a molded shell with a gradient structure through directional arrangement control, and performs interface treatment between layers; S4, the molded shell is subjected to catalytic vulcanization, high-temperature activation and hot air circulation aging simulation in sequence, and the vulcanization temperature is controlled in the range of 160°C to 200°C for staged vulcanization treatment. S5, after the sulfurized shell is surface etched and a fluorinated siloxane protective coating is sprayed, and defect detection and compensation processing based on X-ray imaging are carried out simultaneously. Specifically, step S3 includes the following steps: S31, Mold gradient preheating, the molding mold of the three-barrel injection molding machine is divided into zones for temperature control: the inner molding zone is heated to 120℃, the middle molding zone is kept at 110℃, and the outer molding zone is set to 100℃, with a preheating time of 30±2min. S32, layered sequential injection, the inner layer rubber, the middle layer rubber and the outer layer rubber are injected sequentially through an independent barrel, and the injection pressure is controlled to be 80MPa, 100MPa and 60MPa respectively. When the inner layer rubber is injected, the screw speed is the first speed, the middle layer is increased to the second speed, and the outer layer is reduced to the third speed. S33, during the layered sequential injection process, after each layer is injected, a 3:1 volume ratio argon / nitrogen mixed plasma is sprayed onto the molding surface through a plasma nozzle with a power of 600W and a processing time of 20s to implement interlayer interface treatment. S34, gradient cooling and shaping, after injection, the pressure is held in stages: the first stage is held at 50MPa and the temperature is maintained at 100℃ for 2 minutes, the second stage is reduced to 30MPa and gradient cooled to 60℃, and after demolding, a molded shell with a three-dimensional oriented gradient structure is obtained.

2. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 1, characterized in that, The modification process of the aluminum nitride filler is as follows: S11, pretreated aluminum nitride filler, is made by ultrasonically dispersing aluminum nitride powder of the first particle size in an ethanol-water solution, wherein the volume ratio of ethanol to water is 3:

1. S12, stepwise coupling agent treatment: silane coupling agent is added dropwise to the ultrasonicated suspension while mechanical stirring is performed simultaneously. After the addition is complete, the temperature is raised to 60℃ and reacted at a constant temperature for 1.5 hours to obtain surface-modified aluminum nitride filler.

3. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 2, characterized in that, The specific process by which the conductive carbon black and the silicon carbide whiskers are combined to form core-shell structured composite particles is as follows: S13, Conductive carbon black pre-dispersion: Conductive carbon black of the second particle size is added to an isopropanol solution containing polyvinylpyrrolidone and processed at high speed for 20 minutes using a high-speed shear emulsifier to form a stable dispersion. S14, place silicon carbide whiskers in a plasma treatment device, introduce a mixture of argon and oxygen in a volume ratio of 4:1, and treat for 10 minutes at a preset power to activate the surface of the silicon carbide whiskers. S15, gradient ball milling composite: the activated silicon carbide whiskers and the stable dispersion are added to the ball milling jar at a mass ratio of 1:

3. Zirconia grinding balls are used to perform two-stage ball milling at a preset speed: the first stage is ball milling for 30 minutes to form a physical coating structure, and the second stage is heating to 50°C and adding 0.5wt% polydopamine binder, and continuing ball milling for 60 minutes. S16, vacuum drying treatment: the ball-milled mixture is transferred to a vacuum drying oven and dried at 80℃ and -0.1MPa for 4 hours. After airflow pulverization, core-shell structured composite particles are obtained, in which a continuous conductive carbon black coating layer is formed on the surface of silicon carbide whiskers.

4. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 1, characterized in that, Step S2 specifically includes the following steps: S21, Base material premixing treatment: Methyl vinyl silicone rubber raw rubber and silica are added to a high-speed mixer at a mass ratio of 10:1 and premixed for 15 minutes at 50℃ and 800rpm to form silicone rubber base material. S22, functional layer division, distributes silicone rubber base material into three independent mixing systems—outer layer, middle layer, and inner layer—in a mass ratio of 3:4:

3.

5. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 1, characterized in that, Following step S22, the following is also included: S23, 2wt% hydrophobic nano silica and 0.8wt% carbon nanotube composite anti-aging agent are added to the outer layer rubber compound system, and the mixture is mixed in an internal mixer at 40℃ and 60rpm for 8min to obtain the outer layer rubber compound. S24, 25wt% of surface-modified aluminum nitride filler is added to the intermediate layer rubber compound system, and a two-stage intensive mixing process is adopted: the first stage is low-speed dispersion at 50℃ and 40rpm for 5min, and the second stage is high-speed mixing at 70℃ and 90rpm for 10min to obtain the intermediate layer rubber compound. S25 involves adding 15wt% core-shell composite particles and 0.5wt% chopped carbon fiber filaments to the inner layer rubber compound system, and performing dynamic vulcanization treatment in a twin-screw extruder, controlling the barrel temperature at 80-100℃ and the screw speed at 120rpm to obtain the inner layer rubber compound.

6. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 1, characterized in that, Step S4 specifically includes the following steps: S41, pre-vulcanization catalytic treatment: the molded shell is placed in a closed vulcanization chamber containing 0.5wt% platinum catalyst, nitrogen gas is introduced to protect the environment, the temperature is raised to 160℃ at a rate of 10℃ / min and held at the temperature for 20min to trigger the initial cross-linking of silicone rubber. S42, the sealed vulcanization chamber is heated by gradient temperature increase, and the temperature is increased in multiple stages, while step pressure is applied simultaneously during the vulcanization process; S43, the vulcanized shell is placed in a forced convection oven, and the temperature is circulated and raised at a rate of 200℃ / h with high temperature air at 200℃. Each temperature zone is maintained for 30 minutes, and n complete cycles are completed to simulate hot air circulation aging. S44 was slowly cooled to room temperature under a constant temperature of 80℃ and a negative pressure environment of 0.1MPa, and the cooling rate was controlled to obtain a dimensionally stable vulcanized shell.

7. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 6, characterized in that, Step S42 specifically includes: The temperature was increased in three stages. In the first stage, the temperature was increased to 180℃ at 5℃ / min and treated for 30min to complete the main crosslinking. In the second stage, the temperature was increased to 190℃ at 3℃ / min and treated for 20min to optimize the density. In the third stage, the temperature was increased to 200℃ at 2℃ / min and treated for 10min to eliminate internal stress. The step pressure application process is as follows: maintain 0.5MPa at 160℃, increase to 1.2MPa at 180℃, and decrease to 0.8MPa at 200℃.

8. The method for preparing the silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles according to claim 1, characterized in that, Step S5 specifically includes the following steps: S51, the sulfurized shell is placed in a vacuum chamber and argon / carbon tetrafluoride mixed gas is introduced. It is then subjected to 30s pulsed plasma treatment at 800W radio frequency power to form a rough surface. S52, a protective coating is formed by sequentially spraying a base layer of first thickness and a top layer of second thickness using a two-component electrostatic spray gun, controlling the spraying distance at 200mm, the voltage at 50kV, and the curing interval between layers at 5min; the base layer is a fluorosiloxane binder, and the top layer is a nano-ceramic protective slurry; S53 uses a micro-focus X-ray imaging system to perform three-dimensional scanning of the protective coating and identifies defective areas with porosity or thickness deviation in real time based on an intelligent recognition algorithm. S54, a compensation slurry is sprayed onto the identified defective area using laser-assisted positioning technology, and after local reinforcement, it is cured a second time to form a continuous protective layer; the compensation slurry includes fluorinated siloxane and silicon carbide nanosheets.

9. A silicone rubber housing for a high-voltage wiring harness connector for new energy vehicles, characterized in that, The silicone rubber shell of the high-voltage wiring harness connector for new energy vehicles is prepared by the method described in any one of claims 1 to 8, wherein the silicone rubber shell specifically comprises: The layers, arranged sequentially from the outside in, are a hydrophobic and weather-resistant layer, a directional thermally conductive layer, and a conductive shielding layer, wherein: The hydrophobic weather-resistant layer comprises hydrophobic nano-silica and a gradient cross-linked structure; The directional heat-conducting layer has aluminum nitride filler arranged in a directional manner along the heat flow direction; The conductive shielding layer forms a conductive network of silicon carbide whiskers and conductive carbon black core-shell particles. The surface of the silicone rubber shell is provided with a composite protective layer containing fluorinated siloxane and nano-ceramics.

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