A new energy vehicle cable and a preparation method thereof

Abstract

The application provides a new energy vehicle cable and a preparation method thereof. The preparation method comprises the following steps: placing insulating materials, flame retardants, toughening agents and antioxidants into a double-screw extruder, uniformly mixing and extruding, and cooling to form a coated inner layer; covering a first direction mask plate on the coated inner layer, coating a first functional coating, covering a second direction mask plate after solidification, coating a second functional coating, and forming an intermediate grid layer on the coated inner layer; winding the coated inner layer with the intermediate grid layer on an inner core of a new energy vehicle cable, and then immersing the new energy vehicle cable in a resin mixed solution. The resin mixed solution enters a filling space, is solidified, and forms a protective outer layer, so that the new energy vehicle cable is obtained. The heat dissipation capacity, the electromagnetic shielding effect and the mechanical strength of the new energy vehicle cable are improved.

Description

Technical Field

[0001] This invention belongs to the field of cable material technology, and in particular relates to a cable for new energy vehicles and its preparation method. Background Technology

[0002] Cables used in new energy vehicles typically consist of an inner core, an insulation layer, a shielding layer, and an outer sheath. The operating voltage of new energy vehicle battery packs is usually as high as 400V~800V, and some high-performance models even exceed 1000V. The drive motor and fast charging system need to carry large currents, typically 200A~400A. Therefore, the conductor resistance of cables used in new energy vehicles should comply with national or international standards, such as GB / T5013 or ISO6722.

[0003] First, current technologies primarily rely on metallic conductors for thermal conductivity, but the interface thermal resistance between the inner core and insulation layer is high. The insulation and outer sheath layers are typically made of low-thermal-conductivity polymer materials, hindering heat dissipation. During high-power transmission or prolonged operation, heat accumulates internally, leading to overheating and potentially causing material aging or even fire. Second, single shielding layers (such as metal foil) have limited effectiveness in suppressing broadband electromagnetic interference, especially high-frequency interference (GHz level). Finally, while flexible polymers are often chosen for insulation and outer sheath materials, these materials have limited wear resistance, impact resistance, and vibration resistance, resulting in poor mechanical properties. Under prolonged vibration, high temperatures, or external forces, the cables are prone to aging, deformation, and even breakage. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a cable for new energy vehicles and a method for preparing the same, which aims to solve the problems of poor heat dissipation capacity, electromagnetic shielding effect and mechanical strength of cables for new energy vehicles.

[0005] To address the above problems, this invention proposes a method for preparing cables for new energy vehicles, comprising the following steps:

[0006] S1. The insulating material, flame retardant, toughening agent and antioxidant are placed in a twin-screw extruder, mixed and extruded evenly, and cooled to form a coating inner layer. The mixing temperature is 180~230°C and the mixing time is 5~10min.

[0007] S2. First, a first-direction mask is covered on the inner layer, a first functional coating is applied, and after curing, a second-direction mask is covered and a second functional coating is applied to form an intermediate mesh layer on the inner layer. The first functional coating and the second functional coating in the intermediate mesh layer are intersected and enclosed to form a filling space. The first functional coating or the second functional coating includes at least one of graphene dispersion, carbon nanotube dispersion, silver-plated copper powder coating, boron nitride dispersion, silicon carbide dispersion, carbon fiber reinforced resin, and nano-zirconia coating.

[0008] S3. The inner layer with the intermediate mesh layer is wound around the inner core of the new energy vehicle cable, and then immersed in a resin mixture solution. After the resin mixture solution enters the filling space and cures, a protective outer layer is formed, thus obtaining the new energy vehicle cable. The resin mixture solution includes a thermoplastic resin matrix, anti-UV additives, and wear-resistant reinforcing agents. The curing temperature of the resin mixture solution is 180~250℃.

[0009] In some embodiments of the present invention, in step S2, the extension direction of the first functional coating and the extension direction of the second functional coating have an acute angle A, wherein the acute angle A is 30~90°, and the aperture of the first directional mask and the second directional mask is 1~3mm.

[0010] In some embodiments of the present invention, step S2 includes:

[0011] S2.1. The first functional coating is prepared and ultrasonically dispersed, coated on the inner layer by covering it with a first-direction mask plate, and cured to obtain the first functional coating.

[0012] S2.2 Add magnetic response particles to the second functional coating and mix them evenly. Place the inner layer with the first functional coating in a directional magnetic field. Cover the first functional coating with a second directional mask and then coat it with the second functional coating. After curing, an intermediate mesh layer is formed, and the inner layer with the intermediate mesh layer is obtained. The internal particles of the second functional coating are directionally arranged.

[0013] In some embodiments of the present invention, the curing temperature of the first functional coating and the second functional coating is 150~180℃, and the thickness of the first functional coating and the second functional coating is 0.05~0.1mm.

[0014] In step S2.1, the ultrasonic power of the ultrasonic dispersion is 200~400W, and the ultrasonic time is 10~30min;

[0015] In step S2.2, the magnetic field direction of the directional magnetic field is parallel or perpendicular to the extension direction of the second functional coating. The magnetic response particles include at least one of iron oxide particles, iron-silicon-aluminum particles, iron-based alloy particles, and cobalt ferrite particles. The particle size of the magnetic response particles is 100~500nm.

[0016] In some embodiments of the present invention, in step S1, the insulating material accounts for 50-70 wt% by weight, the flame retardant accounts for 10-20 wt%, the toughening agent accounts for 3-9 wt%, and the antioxidant accounts for 0.1-1 wt%. The insulating material includes at least one of cross-linked polyethylene, polyimide, high-density polyethylene, and ethylene-vinyl acetate copolymer. The flame retardant includes at least one of aluminum hydroxide, magnesium hydroxide, flame-retardant siloxane composite material, red phosphorus, and phosphonate. The toughening agent includes at least one of ethylene-vinyl acetate copolymer, styrene-ethylene-butene-benzene block copolymer, polyacrylate copolymer, and maleic anhydride-grafted polyolefin. The antioxidant includes at least one of butylated hydroxytoluene, dipropyl dilaurate, and triphenyl phosphate.

[0017] In some embodiments of the present invention, by weight percentage, in the resin mixture solution of step S3, the thermoplastic resin matrix accounts for 70-90 wt%, the UV-resistant additive accounts for 3-5 wt%, and the wear-resistant reinforcing agent accounts for 3-7 wt%. The thermoplastic resin matrix includes at least one of polyurethane, polyethylene, polypropylene, and polybutylene terephthalate. The UV-resistant additive includes at least one of hindered amine light stabilizer and benzotriazole UV absorber. The wear-resistant reinforcing agent includes at least one of nano-alumina, nano-silica, and polytetrafluoroethylene micropowder.

[0018] In some embodiments of the present invention, step S1 includes:

[0019] S1.1 Surface modification of the flame retardant with a silane coupling agent, wherein the amount of silane coupling agent added is 1-3 wt% of the flame retardant weight.

[0020] S1.2 Place the insulating material in a vacuum dryer and dry it at a temperature of 60~80°C for 4~6 hours to reduce the moisture content of the insulating material to ≤0.1wt%;

[0021] S1.3 Use a high-speed mixer to stir the toughening agent and antioxidant evenly at a speed of 1000~1500 rpm for 30~60 minutes;

[0022] S1.4 First, add the insulating material to the main hopper of the twin-screw extruder. Add the flame retardant in batches through the side hopper. After the insulating material has been stably melted, add the mixture of toughening agent and antioxidant through the special additive injection port, mix and cool to obtain the inner coating layer.

[0023] In some embodiments of the present invention, step S3 includes:

[0024] S3.1. Dry the thermoplastic resin matrix at a temperature of 80~100°C for 4~6 hours to reduce the moisture content to ≤0.05wt%.

[0025] S3.2 Add the UV-resistant additive, wear-resistant reinforcing agent and diluent to the thermoplastic resin matrix in sequence, and premix for 20 to 30 minutes at a speed of 1000 to 1500 rpm using a high-speed stirrer to obtain a resin mixture solution with a viscosity of 500 to 1500 mPa·s.

[0026] S3.3. The resin mixture solution is heated at a constant temperature. A rotating clamp is used to fix the inner core with the inner layer covered by the intermediate mesh layer on the clamp and slowly immerse it into the resin mixture solution. The constant temperature of the resin mixture solution is 60~80℃, the rotation angle of the rotating clamp is 45~90°, the immersion speed is 1~3mm / s, and the immersion time is 5~10min.

[0027] S3.4 After immersion, slowly remove the inner coating and use a low-speed rotating device to remove the solution so that the thickness of the resin solution on the surface of the inner coating is 0.2~2mm, wherein the rotation speed of the low-speed rotating device is 30~50rpm.

[0028] S3.5. After the inner layer of the coating is removed, it is placed in a vacuum chamber for degassing. After degassing, it is placed in a hot air circulating curing oven for low-temperature circulating pre-curing. After cooling, the cable for new energy vehicles is obtained. The degassing pressure is -0.08 to -0.1 MPa, the degassing time is 3 to 5 minutes, and the curing temperature includes a first stage of 180 to 200°C, a second stage of 200 to 220°C, and a third stage of 220 to 250°C. The curing time of the first stage is 20 to 25 minutes, and the curing time of the second and third stages is 10 to 20 minutes each.

[0029] This invention proposes a new energy vehicle cable, which is prepared by the method described above. The new energy vehicle cable includes an inner conductor, an inner covering layer, an intermediate mesh layer, and a protective outer layer stacked sequentially. The inner conductor is used to realize signal or energy transmission. The inner covering layer is used to protect the inner conductor of the new energy vehicle cable. The intermediate mesh layer is used to improve the thermal conductivity, electrical conductivity, and structural reinforcement of the new energy vehicle cable. The protective outer layer is used to improve the durability of the new energy vehicle cable and ensure the long-term performance of the cable in complex environments.

[0030] Compared with existing technologies, the advantages of the new energy vehicle cable and its manufacturing method disclosed in this invention are as follows:

[0031] The primary and secondary functional coatings may contain thermally conductive materials, which are arranged in a cross-hatching pattern to form a heat conduction path, improving the material's thermal conductivity and facilitating heat dissipation under high current loads in new energy vehicle cables. The cross-hatching grid design of the heat conduction path effectively reduces interfacial thermal resistance and ensures uniform heat diffusion. If the coating contains graphene dispersion, carbon nanotube dispersion, or silver-plated copper powder coating, the cross-hatching structure forms a highly efficient conductive network, enhancing the material's electromagnetic shielding effect and reducing electromagnetic interference. The cross-hatching of the intermediate grid layer provides additional mechanical support, dispersing external forces and improving the cable's compressive and bending resistance. Carbon fiber reinforced resin or nano-zirconia coatings in the coating further improve impact resistance and abrasion resistance. The multi-layered structure formed after cavity filling effectively mitigates differences in thermal expansion coefficients, reduces interfacial stress concentration, and extends the cable's service life. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of a method for preparing cables for new energy vehicles according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of the intermediate mesh layer in a cable for new energy vehicles according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the structure of the intermediate mesh layer in a cable for new energy vehicles according to another embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of the intermediate mesh layer in a cable for new energy vehicles according to another embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of the intermediate mesh layer in a cable for new energy vehicles according to another embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the structure of the first direction mask and the second direction mask in the method for preparing cables for new energy vehicles according to an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the structure of the first direction mask and the second direction mask in the method for preparing cables for new energy vehicles in another embodiment of the present invention.

[0039] In the accompanying drawings, the reference numerals indicate:

[0040] 100. Cable for new energy vehicles; 10. Inner core; 20. Inner covering layer; 30. Intermediate mesh layer; 31. First functional coating; 32. Second functional coating; 33. Filling space; 40. Protective outer layer; 201. First direction mask; 202. Second direction mask. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0042] Please refer to Figure 1 This invention proposes a method for preparing a cable 100 for new energy vehicles, the steps of which include:

[0043] S1. The insulating material, flame retardant, toughening agent, and antioxidant are placed in a twin-screw extruder, uniformly extruded after mixing, and cooled to form the inner coating layer 20. The mixing temperature is 180~230°C, for example, 180°C, 200°C, or 230°C, and the mixing time is 5~10 minutes, for example, 5 minutes, 8 minutes, or 10 minutes. The specific structure of the twin-screw extruder used in this embodiment is known to those skilled in the art and will not be described further here.

[0044] Providing a suitable temperature ensures complete melting of the insulating material, creating a favorable matrix environment for the uniform dispersion of flame retardants, toughening agents, and antioxidants. Ensuring a sufficiently long mixing time allows for uniform distribution of components, preventing material delamination or localized agglomeration. Appropriate temperature and time ensure good bonding between the flame retardant and the insulating material. Appropriate mixing temperature and time ensure uniform dispersion of the toughening agent within the insulating matrix, thereby improving the composite material's impact resistance, tensile strength, and ductility. Uniform dispersion of antioxidants during mixing enhances the composite material's antioxidant properties, thus delaying aging under high temperatures or sunlight.

[0045] In step S1, by weight percentage, the insulating material accounts for 50-70 wt%, for example, 50 wt%, 60 wt%, or 70 wt%; the flame retardant accounts for 10-20 wt%, for example, 10 wt%, 15 wt%, or 20 wt%; the toughening agent accounts for 3-9 wt%, for example, 3 wt%, 6 wt%, or 9 wt%; and the antioxidant accounts for 0.1-1 wt%, for example, 0.1 wt%, 0.5 wt%, or 1 wt%. The insulating material includes at least one of cross-linked polyethylene, polyimide, high-density polyethylene, and ethylene-vinyl acetate copolymer; the flame retardant includes at least one of aluminum hydroxide, magnesium hydroxide, flame-retardant siloxane composite material, red phosphorus, and phosphonates; the toughening agent includes at least one of ethylene-vinyl acetate copolymer, styrene-ethylene-butene-benzene block copolymer, polyacrylate copolymer, and maleic anhydride-grafted polyolefin; and the antioxidant includes at least one of butylated hydroxytoluene, dipropyl dilaurate, and triphenyl phosphate.

[0046] In one embodiment of the present invention, step S1 includes:

[0047] S1.1 Surface modification of the flame retardant with a silane coupling agent, wherein the liquid volume of the added silane coupling agent is 1-3 wt% of the weight of the flame retardant, for example, 1 wt%, 2 wt%, or 3 wt%. The silane coupling agent may be at least one of aminosilane, hydroxysilane, thiol silane, epoxy silane, or alkoxysilane.

[0048] Silane coupling agents significantly improve the dispersibility of flame retardants in the insulating matrix by forming an active coating on the flame retardant surface, preventing particle agglomeration. The organic groups of silane coupling agents are highly compatible with the insulating material, while the inorganic groups chemically bond with the flame retardant surface, thereby enhancing the interfacial bonding between the flame retardant and the matrix. Surface modification can reduce moisture release from the flame retardant during processing, minimizing thermal degradation or bubble formation, ensuring the flame retardant performance of the final product. The modified flame retardant is more uniformly distributed, reducing stress concentration in the matrix material and improving the overall strength and toughness of the material.

[0049] S1.2. Place the insulating material in a vacuum dryer and dry it at a temperature of 60~80°C for 4~6 hours to reduce the moisture content of the insulating material to ≤0.1wt%. The drying temperature can be 60°C, 70°C, or 80°C, and the drying time can be 4 hours, 5 hours, or 6 hours. In this embodiment, the specific structure of the vacuum desiccant used is known to those skilled in the art and will not be described in detail here.

[0050] Vacuum drying effectively removes residual moisture from insulating materials, reducing the moisture content to ≤0.1wt%, thus preventing air bubbles or micropores from forming during subsequent processing. Lower moisture content reduces dielectric loss and conductivity risks, ensuring stable insulation performance of the cable material. The dried insulating material has better flowability, allowing for thorough mixing with flame retardants and toughening agents during compounding, improving processing efficiency and product quality. Low moisture content reduces the risk of hydrolysis during use, extending the product's lifespan in humid or high-temperature environments.

[0051] S1.3. Use a high-speed mixer to uniformly stir the toughening agent and antioxidant at a speed of 1000~1500 rpm for 30~60 minutes. The speed can be 1000 rpm, 1200 rpm, or 1500 rpm, and the stirring time can be 30 minutes, 40 minutes, or 60 minutes. In this embodiment, the specific structure of the high-speed mixer used is known to those skilled in the art and will not be described in detail here.

[0052] High-speed stirring at 1000-1500 rpm ensures thorough dispersion of toughening agents and antioxidants, forming a homogeneous masterbatch that guarantees effective subsequent mixing. The uniformly distributed toughening agent effectively reduces material brittleness, improving the cable's impact resistance and ductility. Uniform stirring prevents antioxidant agglomeration, ensuring even distribution of antioxidant components within the material, thereby enhancing its anti-aging properties. The stirring process optimizes the synergistic effect of the components, laying the foundation for subsequent mixing and molding, and guaranteeing the material's mechanical properties and chemical stability.

[0053] S1.4 First, add the insulating material to the main hopper of the twin-screw extruder. Add the flame retardant in batches through the side hopper. After the insulating material has been stably melted, add the mixture of toughening agent and antioxidant through the special additive injection port. Mix and cool to obtain the inner coating layer 20.

[0054] The twin-screw extruder, through strong shearing and high-temperature melting, ensures uniform mixing of insulating materials, flame retardants, toughening agents, and antioxidants, forming a stable composite material. High-temperature mixing allows the flame retardant to fully contact the matrix material, forming a uniformly distributed flame-retardant barrier layer, effectively improving the material's flame-retardant properties. The toughening agent melts and disperses under high-temperature conditions, forming a tight bond with the matrix material, significantly improving the tensile strength and toughness of the inner coating layer 20. The batch addition of the flame retardant ensures mixing efficiency, avoiding problems such as blockage or uneven mixing caused by excessive instantaneous addition. The uniformly distributed antioxidant protects the material's stability during high-temperature processing and subsequent use, delaying material aging and maintaining excellent long-term insulation performance. The inner coating layer 20, obtained after extrusion cooling, serves as the basic protective layer for the cable, resisting mechanical impact and environmental factors, providing a stable base for the intermediate mesh layer 30.

[0055] S2. First, cover the inner layer 20 with a first-direction mask 201, apply a first functional coating 31, and after curing, cover it with a second-direction mask 202 and apply a second functional coating 32 to form an intermediate mesh layer 30 on the inner layer 20. The first functional coating 31 and the second functional coating 32 in the intermediate mesh layer 30 are intersected and enclosed to form a filling space 33. The first functional coating 31 or the second functional coating 32 includes at least one of graphene dispersion, carbon nanotube dispersion, silver-plated copper powder coating, boron nitride dispersion, silicon carbide dispersion, carbon fiber reinforced resin, and nano-zirconia coating.

[0056] The first functional coating 31 and the second functional coating 32 may contain thermally conductive materials, which are arranged in a cross pattern to form a thermally conductive path, improving the thermal conductivity of the material and facilitating heat dissipation of the new energy vehicle cable under high current loads. The cross-grid design of the thermally conductive path effectively reduces interfacial thermal resistance and ensures uniform heat diffusion. If the coating contains graphene dispersion, carbon nanotube dispersion, or silver-plated copper powder coating, the cross structure forms a highly efficient conductive network, enhancing the electromagnetic shielding effect of the material, reducing electromagnetic interference, improving the antistatic performance of the material, and avoiding the impact of static electricity accumulation on cable operation.

[0057] The intersecting arrangement of the intermediate mesh layer 30 provides additional mechanical support, dispersing external forces and improving the cable's resistance to compression and bending. The carbon fiber reinforced resin or nano-zirconia coating in the paint further enhances impact resistance and abrasion resistance. The multi-layered structure formed after cavity filling effectively mitigates differences in thermal expansion coefficients, reduces interface stress concentration, and extends the cable's service life.

[0058] The filling space 33 formed by the first functional coating 31 and the second functional coating 32 provides a fixed space for filling the resin mixture, ensuring uniform filling. The regular shape and cross-network design of the cavity help control resin flow during subsequent filling processes, prevent air bubble residue, and improve product quality.

[0059] Boron nitride and silicon carbide exhibit excellent high-temperature resistance, and the resulting intermediate mesh layer 30 provides thermal stability at high temperatures. Nano-zirconia coating enhances the corrosion resistance of the intermediate layer, making the cable material suitable for harsher chemical or humid environments.

[0060] The first-direction mask 201 and the second-direction mask 202 can be made of polymeric materials such as polyimide film and polytetrafluoroethylene film. They are reusable, and after being treated with an anti-stick coating, they are suitable for multiple coating processes and are suitable for scenarios requiring high temperature and high mechanical strength.

[0061] In other embodiments, please refer to Figures 2 to 7The first functional coating 31 can be set continuously or intermittently. The openings of the first directional mask 201 and the second directional mask 202 can also be set in an intermittent or continuous manner, so as to be suitable for different actual use cases. The shapes shown in the figure above are only partial examples. In this invention, the specific opening shapes of the first directional mask 201 and the second directional mask 202 are not limited, nor are the specific shapes of the first functional coating 31 and the second functional coating 32.

[0062] In one embodiment, step S2 includes:

[0063] S2.1. The first functional coating 31 is prepared and ultrasonically dispersed. After covering the inner layer 20 with the first direction mask plate 201, the coating is applied and cured to obtain the first functional coating. The ultrasonic power of the ultrasonic dispersion is 200~400W, for example, 200W, 300W, or 400W, and the ultrasonic time is 10~30min, for example, 10min, 20min, or 30min.

[0064] Ultrasonic waves break up the agglomeration of particles in coatings through cavitation, allowing graphene dispersions, carbon nanotube dispersions, and silver-plated copper powder coatings to be uniformly distributed within the coating matrix. This improves coating uniformity and prevents localized excessive concentrations or functional deficiencies. The strong shearing force of ultrasound breaks down large particles into nanoscale particles (e.g., reducing particle diameter to the 10-50 nm range), enhancing the surface activity of the coating. This improves the coating's functional properties, such as thermal conductivity (by reducing interfacial thermal resistance) or electrical conductivity (by forming continuous conductive paths).

[0065] Ultrasonic treatment promotes the interaction between functional particles and dispersants, forming a stable dispersion system and preventing particle sedimentation or aggregation. This improves the coating's application properties in subsequent coating processes and ensures uniform coating thickness.

[0066] Using a first-direction mask 201 ensures the regularity of the coating's shape and distribution, avoiding disordered or redundant coating. This provides clear functional areas, laying the foundation for subsequent cross-coating of the second functional coating 32. The post-coating curing process, through high-temperature treatment (typically 150~200℃), forms a strong interfacial bond between the coating matrix and the inner layer 20, enhancing the coating's mechanical stability and durability, and preventing peeling or lifting. The regularized coating of the first functional layer provides precise positioning for the cross-grid design of the second-direction functional coating, giving the intermediate grid layer 30 higher structural and functional integrity.

[0067] Effects of ultrasonic power (200~400W): Low power (200W): Suitable for dispersing lightweight materials (such as graphene or carbon nanotubes), avoiding damage to the nanosheet structure caused by excessive ultrasonic power. High power (400W): Suitable for dispersing larger or denser particles (such as silver-plated copper powder, nano-zirconia), ensuring their full dispersion.

[0068] The effects of ultrasonic time (10~30min): Short time (10min): Maintains the integrity of particle structure, suitable for functional coatings that are sensitive to particles (such as carbon nanotube dispersions). Long time (30min): Completely disperses high-viscosity coatings or large particles, avoiding particle agglomeration.

[0069] S2.2 Magnetic responsive particles are added to the second functional coating 32 and mixed evenly. The inner layer 20 with the first functional coating is placed in a directional magnetic field. After covering the first functional coating with a second directional mask 202, the second functional coating 32 is applied. After curing, an intermediate mesh layer 30 is formed, resulting in an inner layer 20 with the intermediate mesh layer 30. The internal microparticles of the second functional coating are directionally arranged. The magnetic field direction of the directional magnetic field is parallel or perpendicular to the extension direction of the second functional coating 32. The magnetic responsive particles include at least one of iron(II,III) oxide microparticles, iron-silicon-aluminum microparticles, iron-based alloy microparticles, and cobalt ferrite microparticles. The particle size of the magnetic responsive particles is 100~500 nm, for example, 100 nm, 300 nm, or 500 nm.

[0070] Magnetic responsive particles, under the influence of a directional magnetic field, align in a specific direction, forming a continuous heat-conducting path. Parallel magnetic field: The heat-conducting path is aligned along the extension direction, suitable for improving the longitudinal thermal conductivity of the coating and optimizing the efficiency of heat transfer from the inside of the cable to the outside. Perpendicular magnetic field: The heat-conducting path is aligned perpendicular to the extension direction, helping to improve the heat diffusion capacity across the cross-section. Through directional alignment, the magnetic responsive particles reduce interfacial thermal resistance caused by disordered particle arrangement during heat transfer. This improves the overall thermal conductivity of the coating and enhances the cable's heat dissipation capacity under high current load conditions.

[0071] Magnetic responsive particles possess excellent conductivity, and the directional magnetic field enables them to form a continuous conductive network. A parallel magnetic field creates a low-impedance longitudinal conductive path, improving the coating's conductivity. A perpendicular magnetic field optimizes the coating's lateral conductivity, enhancing electromagnetic shielding. The magnetic responsive particles, arranged in a multi-layered conductive shielding network, effectively reflect and absorb external electromagnetic waves. This improves the coating's resistance to electromagnetic interference and reduces the impact of the external environment on cable signal transmission.

[0072] The magnetically responsive particles are arranged in an orderly manner along the magnetic field direction, improving the uniformity of the coating's internal structure. This enhances the coating's tensile, compressive, and flexural strength, preventing coating damage caused by stress concentration. The magnetically responsive particles with a diameter of 100-500 nm filling the coating significantly enhance its hardness and toughness. This extends the service life of cable materials, making it particularly suitable for mechanical protection needs in complex working environments.

[0073] In step S2, there is an acute angle A between the extension direction of the first functional coating 31 and the extension direction of the second functional coating 32. The acute angle A is 30~90°, for example, it can be 60°, 80°, or 120°. The aperture of the first direction mask 201 and the second direction mask 202 is 1~3mm, for example, it can be 1mm, 2mm, or 3mm.

[0074] A smaller acute angle A provides a higher density grid cross structure, suitable for applications requiring high thermal conductivity, ensuring uniform heat transfer in multiple directions. A 90° acute angle A forms the most classic grid layout, providing balanced thermal conductivity and mechanical support. A larger acute angle A forms a relatively sparse cross grid, suitable for scenarios that balance thermal conductivity and lightweight design. The thermally conductive coating forms multi-directional heat conduction paths within the cross grid, significantly improving the overall thermal diffusion capability of the intermediate grid layer 30. The conductive coating forms three-dimensional conductive channels in the grid cross regions, enhancing the coating's electrical conductivity.

[0075] S3. The inner layer 20 with the intermediate mesh layer 30 is wound around the inner core 10 of the new energy vehicle cable 100, and then immersed in the resin mixture solution. The resin mixture solution enters the filling space 33 and forms a protective outer layer 40 after curing, thus obtaining the new energy vehicle cable 100. The resin mixture solution includes a thermoplastic resin matrix, anti-UV additives and wear-resistant reinforcing agents. The curing temperature of the resin mixture solution is 180~250℃.

[0076] The outer protective layer 40, through the curing of the resin matrix, forms a uniform protective layer that significantly enhances the cable's impact and abrasion resistance. Abrasion-resistant reinforcing agents are uniformly distributed within the resin, increasing surface hardness and extending the cable's service life in complex environments.

[0077] The outer protective layer 40 effectively isolates the inner layers of the cable from moisture, dust, and corrosive chemicals. The dense structure formed by the thermoplastic resin matrix enhances waterproofing and chemical resistance, making it particularly suitable for humid or high-salt-spray environments.

[0078] UV-resistant additives slow down the photodegradation process of the resin matrix by absorbing or reflecting ultraviolet rays. The protective outer layer 40 maintains long-term flexibility and mechanical properties, extending the cable's lifespan in outdoor environments. It prevents the outer layer from aging, cracking, or becoming brittle under prolonged exposure to sunlight.

[0079] The resin matrix forms a cross-linked or crystalline structure during curing at 180~250°C, significantly improving thermal stability and preventing softening or deformation under high-temperature conditions. The protective outer layer 40 can withstand internally generated heat when high-power current passes through it. The synergistic effect of UV-resistant additives and abrasion-resistant reinforcing agents uniformly distributed in the resin mixture enhances the anti-aging properties of the protective outer layer 40. It resists the long-term effects of ultraviolet radiation, oxidation, and mechanical wear, delaying the aging process.

[0080] The resin mixture solution is immersed into the filling space 33 of the intermediate mesh layer 30 through an impregnation process, forming a uniform filling free of air bubbles or voids. The coating thickness and cavity filling amount are controlled to ensure the overall mechanical properties and stability of the structure. During the curing process, the resin matrix forms a strong interfacial bond with the intermediate mesh layer 30, preventing delamination. The enhanced adhesion between the coating and the intermediate mesh layer 30 provides higher peel resistance.

[0081] The immersion process is simple and efficient, suitable for mass production, and reduces production costs. The curing process can be completed quickly using a hot air circulating oven or radiant heating, improving production efficiency.

[0082] By weight percentage, in the resin mixture solution of step S3, the thermoplastic resin matrix accounts for 70-90 wt%, for example, 70 wt%, 80 wt%, or 90 wt%; the UV-resistant additive accounts for 3-5 wt%, for example, 3 wt%, 4 wt%, or 5 wt%; and the wear-resistant reinforcing agent accounts for 3-7 wt%, for example, 3 wt%, 5 wt%, or 7 wt%. The thermoplastic resin matrix includes at least one of polyurethane, polyethylene, polypropylene, and polybutylene terephthalate; the UV-resistant additive includes at least one of hindered amine light stabilizer and benzotriazole UV absorber; and the wear-resistant reinforcing agent includes at least one of nano-alumina, nano-silica, and polytetrafluoroethylene micropowder.

[0083] In one embodiment of the present invention, in order to wrap the inner layer 20 with the intermediate mesh layer 30 around the inner core 10 of the new energy vehicle cable 100, it can be achieved in the following way.

[0084] 1. A winding device using a tension control system, which may include a servo motor, a rotating shaft, etc., automatically adjusts the tension and winding speed of the inner layer 20 to uniformly wind the inner layer 20 onto the surface of the core 10. The tension range can be adjusted according to the material properties, avoiding material slack or excessive stretching during the winding process, and achieving high-precision control of the end-to-end connection.

[0085] 2. Adhesion-assisted techniques, such as hot melt adhesive bonding, involve pre-applying hot melt adhesive (such as modified polyester or polyurethane hot melt adhesive) to the inner surface of the inner layer 20. During the winding process, localized heating melts the adhesive layer, bonding it to the surface of the inner core 10. Alternatively, during the winding process, a liquid adhesive (such as epoxy resin or silicone sealant) can be sprayed or applied to bond the inner layer 20 to the surface of the inner core 10. The inner layer 20 can also be cut at both ends into bevels (e.g., 30°~45°). During the winding process, precise alignment and light pressure ensure a tight joint between the ends, providing a larger contact area and higher bonding strength. A hot press is then used to apply heat and pressure at the joint of the inner layer 20, causing the material to partially melt and seamlessly bond, resulting in a smooth joint without any thickness protrusions.

[0086] The specific structures of all the mechanical equipment used above are known to those skilled in the art and will not be described in detail here.

[0087] In one embodiment of the present invention, step S3 includes:

[0088] S3.1. Dry the thermoplastic resin matrix at a temperature of 80~100°C, such as 80°C, 90°C, or 100°C, for a time of 4~6 hours, such as 4 hours, 5 hours, or 6 hours, to reduce the moisture content to ≤0.05wt%.

[0089] Reducing the moisture content of the thermoplastic resin matrix to ≤0.05wt% effectively prevents air bubbles from forming due to moisture evaporation during subsequent heating or curing, ensuring the material's density. Lowering the moisture content also strengthens the bond between the resin and the intermediate mesh layer 30, improving coating adhesion. Removing moisture reduces hydrolysis and material degradation, ensuring the long-term stability of the cable in high-temperature environments.

[0090] S3.2 The UV-resistant additive, abrasion-resistant reinforcing agent, and diluent are added sequentially to the thermoplastic resin matrix. The mixture is premixed for 20-30 minutes at 1000-1500 rpm using a high-speed stirrer to obtain a resin mixture with a viscosity of 500-1500 mPa·s. The specific structure of the high-speed stirrer is known to those skilled in the art and will not be described in detail here. The stirring speed can be 1000 rpm, 1200 rpm, 1500 rpm, etc., the stirring time can be 20 minutes, 25 minutes, or 30 minutes, and the viscosity of the resin mixture can be 500 mPa·s, 1000 mPa·s, or 1500 mPa·s.

[0091] The UV-resistant additives and abrasion-resistant enhancers are fully dispersed during high-speed stirring to form a stable resin mixture, preventing component separation or particle aggregation during subsequent use. The viscosity is controlled between 500 and 1500 mPa·s to ensure that the resin mixture can uniformly penetrate the filling spaces 33 of the intermediate mesh layer 30 during coating, while avoiding sagging. The uniform distribution of the UV-resistant additives ensures the UV resistance of the protective outer layer 40, while the uniform distribution of the abrasion-resistant enhancers improves surface hardness and scratch resistance, extending the cable's service life.

[0092] S3.3. A constant-temperature heated resin mixture solution is provided, equipped with a rotating clamp, to fix the inner core 10 with the inner layer 20 wrapped with the intermediate mesh layer 30 on the clamp and slowly immerse it in the resin mixture solution. The constant temperature of the resin mixture solution is 60~80℃, for example, 60℃, 70℃, or 80℃. The rotation angle of the rotating clamp is 45~90°, for example, 45°, 50°, or 90°. The immersion speed is 1~3mm / s, for example, 1mm / s, 2mm / s, or 3mm / s. The immersion time is 5~10min, for example, 5min, 8min, or 10min.

[0093] Constant temperature heating maintains the fluidity of the resin mixture solution, while slow immersion of the rotating fixture ensures uniform penetration of the solution into the filling spaces 33 of the intermediate mesh layer 30. Precise control of immersion speed and time prevents incomplete filling of cavities due to excessive speed or over-coating due to excessive slowness. Coordination of temperature and angle during immersion reduces air retention and ensures a bubble-free or defect-free coating. Controlling the rotation of the fixture and the immersion depth ensures that the resin mixture solution uniformly covers the entire surface of the inner coating layer 20.

[0094] S3.4 After immersion, slowly remove the inner layer 20 and use a low-speed rotating device to remove the solution so that the thickness of the resin solution on the surface of the inner layer 20 is 0.2~2mm, for example, 0.2mm, 1mm, or 2mm. The rotation speed of the low-speed rotating device is 30~50rpm, for example, 30rpm, 40rpm, or 50rpm.

[0095] Excess resin solution is removed by a low-speed rotating device, ensuring the thickness of the protective outer layer 40 remains within 0.22mm, meeting mechanical protection requirements while avoiding material waste. The low-speed rotation ensures uniform flow of residual resin on the surface, preventing uneven thickness or defects caused by localized accumulation. This detachment process simplifies manual adjustments and is suitable for mass automated production.

[0096] S3.5. After the inner layer 20 is removed, it is placed in a vacuum chamber for degassing. After degassing, it is placed in a hot air circulating curing oven for low-temperature circulating pre-curing. After cooling, the new energy vehicle cable 100 is obtained. The degassing time is 3-5 min, 3 min, 4 min, and 5 min. The curing temperature includes a first stage of 180-200℃, a second stage of 200-220℃, and a third stage of 220-250℃. The curing time of the first stage is 20-25 min, and the curing time of the second and third stages is 10-20 min.

[0097] The specific mechanical structures of all the devices used in step S3 are known to those skilled in the art and will not be described in detail here.

[0098] The present invention also proposes a new energy vehicle cable 100, comprising an inner covering layer 20, a middle mesh layer 30, and a protective outer layer 40. The inner covering layer 20 is used to protect the internal conductors of the new energy vehicle cable 100 and prevent current leakage. The middle mesh layer 30 is used to improve the thermal conductivity, electrical conductivity, and structural reinforcement of the new energy vehicle cable 100. The protective outer layer 40 is used to improve the durability of the new energy vehicle cable 100 and ensure the long-term performance of the cable in complex environments.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing cables for new energy vehicles, characterized in that the steps include... include: S1. The insulating material, flame retardant, toughening agent and antioxidant are placed in a twin-screw extruder, mixed and extruded evenly, and cooled to form a coating inner layer. The mixing temperature is 180~230°C and the mixing time is 5~10min. S2. First, a first-direction mask is covered on the inner layer, a first functional coating is applied, and after curing, a second-direction mask is covered and a second functional coating is applied, forming an intermediate grid layer on the inner layer. The first and second functional coatings in the intermediate grid layer are intersected and enclosed to form a filling space. The first or second functional coating includes at least one of graphene dispersion, carbon nanotube dispersion, silver-plated copper powder coating, boron nitride dispersion, silicon carbide dispersion, carbon fiber reinforced resin, and nano-zirconia coating. The first functional coating can be continuously or intermittently arranged. The openings of the first and second-direction masks can be arranged in an intermittent or continuous manner. Step S2 includes: S2.

1. The first functional coating is prepared and ultrasonically dispersed. After covering the inner layer with a first-direction mask, the coating is applied and cured to obtain the first functional coating. The ultrasonic power of the ultrasonic dispersion is 200~400W and the ultrasonic time is 10~30min. S2.2 Magnetic responsive particles are added to the second functional coating and mixed evenly. The inner layer with the first functional coating is placed in a directional magnetic field. After covering the first functional coating with a second directional mask, the second functional coating is coated. After curing, an intermediate mesh layer is formed, and the inner layer with the intermediate mesh layer is obtained. The internal microparticles of the second functional coating are directionally arranged. The magnetic field direction of the directional magnetic field is parallel or perpendicular to the extension direction of the second functional coating. The magnetic responsive particles include at least one of iron oxide microparticles, iron-silicon-aluminum microparticles, iron-based alloy microparticles, and cobalt ferrite microparticles. The particle size of the magnetic responsive particles is 100~500nm. The extension direction of the first functional coating (31) and the extension direction of the second functional coating (32) have an acute angle (A), wherein the acute angle (A) is 30~90°; S3. The inner layer with the intermediate mesh layer is wound around the inner core of the new energy vehicle cable, and then immersed in a resin mixture solution. After the resin mixture solution enters the filling space and cures, a protective outer layer is formed, thus obtaining the new energy vehicle cable. The resin mixture solution includes a thermoplastic resin matrix, UV-resistant additives and wear-resistant reinforcing agents, and the curing temperature of the resin mixture solution is 180~250℃. Step S3 includes: S3.

1. Dry the thermoplastic resin matrix at a temperature of 80~100°C for 4~6 hours to reduce the moisture content to ≤0.05wt%. S3.2 Add the UV-resistant additive, wear-resistant reinforcing agent and diluent to the thermoplastic resin matrix in sequence, and premix for 20 to 30 minutes at a speed of 1000 to 1500 rpm using a high-speed stirrer to obtain a resin mixture solution with a viscosity of 500 to 1500 mPa·s. S3.

3. The resin mixture solution is heated at a constant temperature. A rotating clamp is used to fix the inner core with the inner layer covered by the intermediate mesh layer on the clamp and slowly immerse it into the resin mixture solution. The constant temperature of the resin mixture solution is 60~80℃, the rotation angle of the rotating clamp is 45~90°, the immersion speed is 1~3mm / s, and the immersion time is 5~10min. S3.4 After immersion, slowly remove the inner coating and use a low-speed rotating device to remove the solution so that the thickness of the resin solution on the surface of the inner coating is 0.2~2mm, wherein the rotation speed of the low-speed rotating device is 30~50rpm. S3.

5. After the inner layer of the coating is removed, it is placed in a vacuum chamber for degassing. After degassing, it is placed in a hot air circulating curing oven for low-temperature circulating pre-curing. After cooling, the cable for new energy vehicles is obtained. The degassing time is 3-5 minutes. The curing temperature includes a first stage of 180-200℃, a second stage of 200-220℃, and a third stage of 220-250℃. The curing time of the first stage is 20-25 minutes, and the curing time of the second and third stages is 10-20 minutes each.

2. The method for preparing cables for new energy vehicles according to claim 1, characterized in that, In step S1, by weight percentage, the insulating material accounts for 50-70 wt%, the flame retardant accounts for 10-20 wt%, the toughening agent accounts for 3-9 wt%, and the antioxidant accounts for 0.1-1 wt%. The insulating material includes at least one of cross-linked polyethylene, polyimide, high-density polyethylene, and ethylene-vinyl acetate copolymer. The flame retardant includes at least one of aluminum hydroxide, magnesium hydroxide, flame-retardant siloxane composite material, red phosphorus, and phosphonate. The toughening agent includes at least one of ethylene-vinyl acetate copolymer, styrene-ethylene-butene-benzene block copolymer, polyacrylate copolymer, and maleic anhydride-grafted polyolefin. The antioxidant includes at least one of butylated hydroxytoluene, dipropyl dilaurate, and triphenyl phosphate.

3. The method for preparing cables for new energy vehicles according to claim 1, characterized in that, In the resin mixture solution of step S3, calculated by weight percentage, the thermoplastic resin matrix accounts for 70-90 wt%, the UV-resistant additive accounts for 3-5 wt%, and the wear-resistant reinforcing agent accounts for 3-7 wt%. The thermoplastic resin matrix includes at least one of polyurethane, polyethylene, polypropylene, and polybutylene terephthalate. The UV-resistant additive includes at least one of hindered amine light stabilizer and benzotriazole UV absorber. The wear-resistant reinforcing agent includes at least one of nano-alumina, nano-silica, and polytetrafluoroethylene micropowder.

4. The method for preparing cables for new energy vehicles according to claim 1, characterized in that, Step S1 includes: S1.1 Surface modification of the flame retardant with a silane coupling agent, wherein the amount of silane coupling agent added is 1-3 wt% of the flame retardant weight. S1.2 Place the insulating material in a vacuum dryer and dry it at a temperature of 60~80°C for 4~6 hours to reduce the moisture content of the insulating material to ≤0.1wt%; S1.3 Use a high-speed mixer to stir the toughening agent and antioxidant evenly at a speed of 1000~1500 rpm for 30~60 minutes; S1.4 First, add the insulating material to the main hopper of the twin-screw extruder. Add the flame retardant in batches through the side hopper. After the insulating material has been stably melted, add the mixture of toughening agent and antioxidant through the special additive injection port, mix and cool to obtain the inner coating layer.

5. A cable for new energy vehicles, characterized in that, The new energy vehicle cable is prepared by the method described in any one of claims 1-4. The new energy vehicle cable includes an inner conductor, an inner covering layer, an intermediate mesh layer, and a protective outer layer stacked sequentially. The inner conductor is used to realize signal or energy transmission. The inner covering layer is used to protect the inner conductor of the new energy vehicle cable. The intermediate mesh layer is used to improve the thermal conductivity, electrical conductivity, and structural reinforcement of the new energy vehicle cable. The protective outer layer is used to improve the durability of the new energy vehicle cable and ensure the long-term performance of the cable in complex environments.

Images