Preparation method of vehicle high-voltage cable and vehicle high-voltage cable

Abstract

The invention discloses a vehicle high-voltage cable preparation method and a vehicle high-voltage cable, and belongs to the technical field of vehicle cables. The preparation method of the high-voltage cable for the vehicle comprises the following steps that S1, a conductor is formed in a three-layer twisting mode, and the twisting directions of the three-layer structure of the conductor from inside to outside are all the left twisting directions; s2, forming an insulating layer on the outer wall surface of the conductor in an extrusion mode; s3, forming an inner braided layer on the outer wall surface of the insulating layer by using a braiding machine; s4, spirally winding an aluminum foil formed by compounding an AL layer, a PET layer and a GLUE layer on the outer wall surface of the inner braid layer, wherein the GLUE layer of the aluminum foil is a hot-melt polyurethane adhesive; s5, a sheath layer is formed on the outer wall surface of the aluminum foil in an extrusion mode, and the aluminum foil is bonded with the sheath layer; and S6, forming an outer braided layer on the outer wall surface of the sheath layer by using a braiding machine. The tensile strength of the high-voltage cable for the vehicle can be improved, and the stress generated when the wire is bent is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle cables, and in particular to a method for preparing a vehicle high-voltage cable and the vehicle high-voltage cable. Background Art

[0002] New energy vehicles (NEVs) use unconventional fuels as their power source (or use conventional fuels with new onboard power units) and incorporate advanced technologies in vehicle power control and drive to create vehicles with advanced technical principles, new technologies, and new structures. New energy vehicles use high-voltage cables to connect the electrical equipment in the front of the vehicle to the electrical equipment in the chassis.

[0003] In related technologies, due to the poor flexibility of high-voltage cables, on the one hand, the high-voltage cables of new energy vehicles will be subject to bumps and vibrations during driving, which can easily cause the high-voltage cables to be torn off; on the other hand, in the space with a relatively complex installation environment inside the vehicle, the high-voltage cables are laid on the working surface of the curved path, and the internal conductors of the high-voltage cables are prone to stress due to bending.

[0004] New energy vehicles, a key development direction for the automotive industry, represent a revolutionary trend in future automotive technology. These vehicles utilize unconventional fuels (such as electricity and hydrogen) as their power source. These vehicles not only help reduce reliance on traditional fossil fuels and lower carbon emissions, but also offer significant advantages in improving energy efficiency and environmental quality.

[0005] In the electrical systems of new energy vehicles, high-voltage cables are typically used to connect the electrical equipment in the front of the vehicle to those in the chassis. High-voltage cables play a critical role in transmitting electrical energy in new energy vehicles, and their performance directly impacts the stability and reliability of the entire electrical system.

[0006] However, the lack of flexibility in high-voltage cables is a particularly prominent issue in practical applications. On the one hand, new energy vehicles inevitably experience various bumps and vibrations during driving. These bumps and vibrations continuously act on the high-voltage cables. Due to their lack of flexibility, high-voltage cables are unable to effectively buffer and dissipate these external forces, which can easily cause the cables to break over time. Once a high-voltage cable breaks, not only does it interrupt power transmission, affecting normal driving, but it can also cause electrical failures and even safety accidents, posing a threat to the safety of drivers and passengers. Furthermore, the installation environment inside new energy vehicles is complex and compact, requiring high-voltage cables to be laid along curved working surfaces. In these situations, the bending of the high-voltage cables can easily cause stress in the internal conductors. This stress accumulates over vehicle use, potentially leading to fatigue damage and fracture of the conductors.

[0007] This section provides background information related to the present application which is not necessarily prior art. Summary of the Invention

[0008] The object of the present invention is to provide a method for preparing a high-voltage cable for a vehicle and a high-voltage cable for a vehicle, thereby increasing the tensile strength of the high-voltage cable for a vehicle and reducing the stress generated when the conductor is bent.

[0009] To achieve the above objectives, the following technical solutions are provided:

[0010] A method for preparing a high-voltage cable for a vehicle comprises the following steps:

[0011] S1. The conductor is formed by a three-layer twisting method, and the three-layer structure of the conductor is twisted in a left-hand direction from the inside to the outside;

[0012] S2. forming an insulating layer on the outer wall surface of the conductor by extrusion;

[0013] S3, forming an inner braided layer on the outer wall surface of the insulating layer using a braiding machine;

[0014] S4, an aluminum foil formed by a composite of an AL layer, a PET layer and a GLUE layer is spirally wrapped around the outer wall surface of the inner woven layer, wherein the GLUE layer of the aluminum foil is a hot-melt polyurethane adhesive;

[0015] S5, forming a sheath layer on the outer wall surface of the aluminum foil by extrusion, and bonding the GLUE layer of the aluminum foil to the sheath layer;

[0016] S6. Using the braiding machine to form an outer braided layer on the outer wall surface of the sheath layer.

[0017] As an optional solution to the method for preparing a high-voltage automotive cable, in step S1, the three-layer structure of the conductor includes a first layer structure, a second layer structure and a third layer structure, the first layer structure includes one strand, the second layer structure includes six strands, and the twisting direction of the six strands is left-twisted, the third layer structure includes twelve strands, and the twisting direction of the twelve strands is left-twisted, each strand includes several wires, and the twisting direction of the several wires is left-twisted.

[0018] As an optional solution for the method of preparing a high-voltage cable for a vehicle, the material of the insulating layer is cross-linked polyolefin.

[0019] As an optional solution for the method of preparing a high-voltage cable for a vehicle, LLDPE7042 is filled in the cross-linked polyolefin.

[0020] As an optional solution of the method for preparing a high-voltage cable for a vehicle, the material of the sheath layer is the same as that of the insulation layer.

[0021] As an optional solution to the method for preparing a high-voltage cable for a vehicle, outer surfaces of the insulating layer and the sheath layer are both frosted.

[0022] As an optional solution of the method for preparing a high-voltage cable for a vehicle, in step S3, tinned copper-clad steel wire is used to braid the inner braided layer.

[0023] As an optional solution for the method of preparing a high-voltage cable for a vehicle, the outer braided layer is woven with flame-retardant polyester yarn.

[0024] As an optional solution to the method for preparing a high-voltage cable for a vehicle, an organic silicone resin is coated on the outer surface of the outer braided layer.

[0025] A high-voltage cable for a vehicle is manufactured using the method for preparing a high-voltage cable for a vehicle as described in any of the above items. The high-voltage cable for a vehicle comprises, from the inside to the outside, a conductor, an insulating layer, an inner braided layer, an aluminum foil, a sheath layer, and an outer braided layer. The thickness of the Al layer in the aluminum foil is 15 μm.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The present invention provides a method for preparing a high-voltage automotive cable, comprising the following steps: S1. forming a conductor using a three-layer twisting method, wherein the three layers of the conductor are all twisted in a left-hand direction from the inside out; S2. forming an insulating layer on the outer surface of the conductor by extrusion; S3. forming an inner braided layer on the outer surface of the insulating layer using a braiding machine; S4. spirally wrapping an aluminum foil composed of an AL layer, a PET layer, and a GLUE layer around the outer surface of the inner braided layer, wherein the GLUE layer of the aluminum foil is a hot-melt polyurethane adhesive; S5. forming a sheath layer on the outer surface of the aluminum foil by extrusion, and bonding the GLUE layer to the sheath layer; S6. forming an outer braided layer on the outer surface of the sheath layer using a braiding machine. The conductor is a multi-strand twisted structure, with three layers twisted in the same direction, with the twist directions from the inside out being SSS, replacing traditional layers with different twist directions, such as ZSZ. This design reduces the bending stress generated by the inner and outer layers bending during conductor bending, making the cable more flexible and easier to bend. An insulation layer, inner braided layer, aluminum foil, jacket layer, and outer braided layer are sequentially added to the conductor's outer surface, increasing the tensile strength of the automotive high-voltage cable while also protecting the conductor from abrasion. The aluminum foil is a hot-melt, self-adhesive composite composed of an AL layer, a PET layer, and a GLUE layer. The GLUE layer is a hot-melt polyurethane adhesive. During the formation of the jacket layer in step S5, the high temperature of the jacket layer raises the temperature of the aluminum foil, allowing the heated GLUE layer to adhere tightly to the jacket layer. This allows the wiring harness to be processed in a single step during the cutting process of the automotive high-voltage cable.

[0028] The automotive high-voltage cable provided by the present invention is manufactured using the above-mentioned automotive high-voltage cable preparation method. The automotive high-voltage cable includes, from the inside to the outside, a conductor, an insulating layer, an inner braided layer, an aluminum foil, a sheath layer, and an outer braided layer. The thickness of the Al layer in the aluminum foil is 15 μm, and the aluminum layer is thickened to improve the ability to resist high-frequency signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in describing the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without any creative work.

[0030] Figure 1 Flowchart of a method for preparing a high-voltage cable for a vehicle according to an embodiment of the present invention;

[0031] Figure 2 is a cross-sectional view of a high-voltage cable for a vehicle according to an embodiment of the present invention;

[0032] Figure 3 4 is a cross-sectional view of the aluminum foil in an embodiment of the present invention.

[0033] Reference numerals:

[0034] 1. Conductor; 2. Insulation layer; 3. Inner braid; 4. Aluminum foil; 5. Sheath; 6. Outer braid;

[0035] 41. AL layer; 42. PET layer; 43. GLUE layer. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0037] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0038] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0039] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0040] New energy vehicles inevitably experience various bumps and vibrations during driving. These bumps and vibrations continuously act on high-voltage cables. Due to their lack of flexibility, high-voltage cables are unable to effectively buffer and dissipate these external forces, which can easily cause the cables to break over time. Once a high-voltage cable is torn, it not only interrupts the vehicle's power transmission, affecting normal driving, but can also cause electrical failures and even safety accidents, posing a threat to the safety of drivers and passengers. The installation environment inside new energy vehicles is complex and compact, and high-voltage cables often need to be laid along curved working surfaces. In these situations, the bending of the high-voltage cables easily causes stress in the internal conductors. This stress accumulates over vehicle use, potentially leading to fatigue damage and fracture of the conductors.

[0041] In order to increase the tensile strength of the high-voltage cable for vehicles and reduce the stress generated when the wire is bent, this embodiment provides a method for preparing a high-voltage cable for vehicles. Figures 1 to 3The specific contents of this embodiment are described in detail. It should be noted that the cable twisting direction mentioned in this embodiment is S, which means that when the single wires (such as wires or fibers) in the cable are twisted, their spiral winding direction is left-handed, that is, counterclockwise. Definition: The origin of the naming of the S twisting direction: In the fields of electrical engineering and cable manufacturing, S and Z are used to vividly represent the twisting direction of the cable. The shape of S is similar to the spiral shape when the cable is twisted in a left-handed (counterclockwise) direction; while Z is similar to the shape when it is twisted in a right-handed (clockwise) direction. The difference from the Z twisting direction: The Z twisting direction is opposite to the S twisting direction, which means that the single wires in the cable are twisted in a right-handed (clockwise) direction. The judgment method includes observation method and comparison method. Observation method: Place the cable vertically so that the axis of the cable is perpendicular to the line of sight. If, when viewed from one end of a cable, the spiral direction of the individual wires is counterclockwise, resembling the shape of the letter S, then the cable's twist direction is S. Conversely, if the spiral direction is clockwise, resembling the shape of the letter Z, then the twist direction is Z. Comparison method: Prepare a standard cable sample with a known twist direction (S or Z) as a reference. Compare the cable to be tested against the standard sample to see if the twist directions of the individual wires are consistent, thereby determining the twist direction of the cable to be tested.

[0042] At a time when the new energy vehicle industry is booming, automotive high-voltage cables are key components in the vehicle electrical system, and their performance is directly related to the safety, reliability, and stability of the vehicle. This embodiment provides a method for preparing automotive high-voltage cables, comprising the following steps: S1, forming a conductor 1 by a three-layer twisting method, wherein the three-layer structure of the conductor 1 is twisted in a left-hand direction from the inside to the outside; S2, forming an insulating layer 2 on the outer wall of the conductor 1 by extrusion; S3, forming an inner braided layer 3 on the outer wall of the insulating layer 2 by a braiding machine; S4, spirally winding an aluminum foil 4 formed by a composite of an AL layer 41, a PET layer 42, and a GLUE layer 43 on the outer wall of the inner braided layer 3, wherein the GLUE layer 43 of the aluminum foil 4 is a hot-melt polyurethane adhesive; S5, forming a sheath layer 5 on the outer wall of the aluminum foil 4 by extrusion, and the GLUE layer 43 of the aluminum foil 4 is bonded to the sheath layer 5; S6, forming an outer braided layer 6 on the outer wall of the sheath layer 5 by a braiding machine.

[0043] It can be understood that step S1 is a conductor 1 twisting process: a three-layer twisting method is used to form the conductor 1. The three-layer structure of the conductor 1 is uniformly set to a left twist direction from the inside to the outside. Specifically, the twist direction from the inside to the outside is the SSS direction. This design is different from the traditional anisotropic twisting structure between layers, such as the common ZSZ structure. In the traditional anisotropic twisting structure, the wires between different layers will generate large mutual bending stresses due to the different twisting directions when bending. This stress is easily accumulated during the repeated bending of the cable, resulting in a degradation of the cable performance or even damage. The three-layer unidirectional twisting structure adopted in this preparation method can effectively reduce the bending stress generated by the mutual bending between the inner and outer layers during the bending of the wires. When the cable is bent by external force, the wires of each layer can deform more coordinated, making the cable as a whole more flexible and easier to bend, thereby adapting to the complex and changeable installation environment inside new energy vehicles.

[0044] As can be understood, step S2 is the extrusion process for the insulation layer 2: The insulation layer 2 is formed on the outer surface of the conductor 1 through an extrusion process. Extrusion is an efficient and continuous production method that ensures that the insulation layer 2 is evenly wrapped around the surface of the conductor 1, forming an excellent electrical insulation barrier. This insulation layer 2 effectively prevents current leakage and ensures the safe operation of the electrical system. Furthermore, the extrusion process allows for precise control of the thickness and material of the insulation layer 2 according to specific needs, thereby meeting the insulation requirements of automotive high-voltage cables in different operating environments.

[0045] As can be understood, step S3 is the process of forming the inner braided layer 3: using a braiding machine, the inner braided layer 3 is formed on the outer surface of the insulating layer 2. The braiding process allows the fibers to be interwoven at a specific angle and density, forming a mesh structure with a certain strength and flexibility. The inner braided layer 3 not only enhances the tensile strength of the cable, preventing the cable from breaking when pulled by external forces, but also provides a certain degree of protection for the insulating layer 2, preventing it from being scratched and damaged by external objects.

[0046] As can be understood, step S4 involves the spiral wrapping of the aluminum foil 4. A hot-melt, self-adhesive aluminum foil 4, formed by a composite of an AL layer 41 (aluminum), a PET layer 42 (polyester film), and a GLUE layer 43 (which can be a hot-melt polyurethane adhesive), is spirally wrapped around the outer surface of the inner braided layer 3. The aluminum foil 4 exhibits excellent electromagnetic shielding properties, effectively blocking external electromagnetic interference from affecting signal transmission within the cable. It also prevents electromagnetic radiation leakage from within the cable, ensuring the proper operation of in-vehicle electronic devices. The PET film provides excellent mechanical strength and flexibility, enhancing the overall performance of the aluminum foil 4.

[0047] It can be understood that step S5 is the extrusion and bonding process of the sheath layer 5: the sheath layer 5 is formed on the outer wall surface of the aluminum foil 4 by extrusion, and in the process of forming the sheath layer 5, the high-temperature sheath layer 5 can increase the temperature of the aluminum foil 4. After reaching its melting point (about 85°C), the GLUE layer 43 (also called the hot melt layer) of the aluminum foil 4 will be tightly bonded to the sheath layer 5. This bonding method not only enhances the overall structural strength of the cable, but also enables the wiring harness processing to be completed in one step when cutting automotive high-voltage cables, thereby improving production efficiency, reducing production costs, and also reducing the quality risks that may be caused by multiple processes.

[0048] As can be understood, step S6 is the process of forming the outer braided layer 6: Finally, a braiding machine is used to form the outer braided layer 6 on the outer wall surface of the sheath layer 5. The outer braided layer 6 further enhances the tensile strength and abrasion resistance of the cable, enabling it to withstand various external forces encountered during vehicle operation and protecting the cable's internal structure from damage. Furthermore, the outer braided layer 6 also provides a certain degree of shielding, reducing the impact of external electromagnetic interference on cable signal transmission.

[0049] In this embodiment, an insulating layer 2, an inner braided layer 3, an aluminum foil 4, a jacket layer 5, and an outer braided layer 6 are sequentially added to the outer surface of the conductor 1. These structural layers work together to significantly improve the tensile strength and wear resistance of the automotive high-voltage cable. The insulating layer 2 and jacket layer 5 provide excellent protection for the conductor 1, preventing it from being corroded by the external environment and mechanically damaged. The inner braided layer 3 and outer braided layer 6, through their interwoven fiber structure, enhance the overall strength of the cable, enabling it to withstand greater tension and friction, thereby extending the cable's service life. This enhances the tensile strength and wear resistance of the automotive high-voltage cable.

[0050] Furthermore, in step S1, the three-layer structure of conductor 1 includes a first layer structure, a second layer structure, and a third layer structure. The first layer structure includes one strand, the second layer structure includes six strands, and the twist direction of the six strands is left-handed. The third layer structure includes twelve strands, and the twist direction of the twelve strands is left-handed. Each strand includes a plurality of wires, and the twist direction of the plurality of wires is left-handed. The first layer structure is the innermost layer of conductor 1. It is composed of only one strand and is the basic support for the entire conductor 1 structure. It provides a starting point and core framework for the twisting of subsequent layers. The second layer structure surrounds the first layer structure and tightly twists six strands, and the twist direction of these six strands is clearly left-handed. These six strands are evenly arranged and twisted together at specific angles and spacings with the first layer strand as the center, forming a relatively stable intermediate layer structure. This twisting method not only enhances the overall strength of conductor 1, but also provides a good foundation for the twisting of the third layer strands. The third outermost layer consists of twelve strands of wire, each twisted in a left-hand lay. The third layer tightly wraps around the second layer, further increasing the diameter and cross-sectional area of ​​conductor 1 and thus its current-carrying capacity. Furthermore, the three layers of wires work together to form a compact and orderly overall structure.

[0051] Furthermore, the insulating layer 2 is made of cross-linked polyolefin. Cross-linked polyolefin is a polymer material that undergoes a special process. It is based on polyolefin, and its molecular structure is altered through a cross-linking reaction. Ordinary polyolefin materials have linear molecular chains. Under conditions such as high temperature, high pressure, or long-term stress, the molecular chains are prone to relative slippage, resulting in a decrease in the material's physical and electrical properties. However, after the cross-linking process, the molecular chains of cross-linked polyolefin are chemically bonded, forming a three-dimensional network structure. This structure significantly improves the material's performance.

[0052] Cross-linked polyolefins offer high insulation resistance, low dielectric loss, and excellent corona resistance. The three-dimensional network structure of cross-linked polyolefins restricts the movement of molecular chains, reducing the migration of free electrons and ions. Under the influence of an electric field, the migration of free electrons and ions is one of the main causes of electrical leakage. Because cross-linked polyolefins effectively inhibit this migration, they possess extremely high insulation resistance. This means that in automotive high-voltage cables, current can be strictly confined to flow within the conductor 1, significantly reducing the risk of electrical leakage and ensuring the safe operation of the electrical system. Dielectric loss refers to the electrical energy consumed by a material in an alternating electric field due to factors such as dielectric polarization and conductivity. Cross-linked polyolefins have a low dielectric constant and dielectric loss factor. Under the influence of an alternating electric field, their internal polarization process can quickly respond to changes in the electric field, reducing energy loss due to polarization hysteresis. This not only improves the cable's energy transmission efficiency but also reduces the heat generated by dielectric loss during operation, helping to maintain the cable's normal operating temperature and extending its service life. In high-voltage electric fields, corona discharge may occur on the surface of the cable's insulation layer 2. Corona discharge can cause localized overheating, chemical corrosion, and physical damage to the surface of the insulation layer 2, thereby degrading insulation performance. Cross-linked polyolefins have excellent corona resistance. Their stable molecular structure allows them to withstand high electric field strengths without causing corona discharge. Even under long-term exposure to high-voltage electric fields, they maintain excellent insulation performance, ensuring reliable operation of the cable in high-voltage environments.

[0053] Cross-linked polyolefins offer high heat resistance, excellent thermal stability, and a low coefficient of thermal expansion. High-voltage automotive cables generate a certain amount of heat during operation, especially when transmitting high currents, which can significantly increase the cable's temperature. Cross-linked polyolefins have a high heat resistance, maintaining stable physical and electrical properties at elevated temperatures. They have a high melting point and a relatively high thermal decomposition temperature, preventing softening, deformation, or decomposition within the normal operating temperature range. This enables high-voltage automotive cables to operate normally in high-temperature environments, meeting the demands of high-temperature areas such as the engine compartment of new energy vehicles. In addition to their high heat resistance, cross-linked polyolefins also possess excellent thermal stability. Their molecular structure remains stable under long-term high-temperature conditions, resulting in minimal performance degradation. This means that the performance of the insulation layer 2 remains relatively stable during long-term cable use, preventing degradation due to temperature fluctuations, thereby ensuring the long-term reliability and safety of the cable. The coefficient of thermal expansion refers to the degree to which a material changes in volume or length with temperature changes. Cross-linked polyolefins have a low coefficient of thermal expansion, resulting in minimal dimensional changes with temperature fluctuations. This is crucial for automotive high-voltage cables, as they are subject to temperature fluctuations during installation and use. A high thermal expansion coefficient of insulation layer 2 can cause changes in the gaps between the cable and conductor 1, and between the cable and other components, affecting the cable's electrical and mechanical properties. A low thermal expansion coefficient ensures good dimensional stability during temperature fluctuations, reduces stress caused by thermal expansion and contraction, and improves cable reliability and service life.

[0054] Furthermore, LLDPE7042 is filled in the cross-linked polyolefin. LLDPE7042 is a linear low-density polyethylene, which is copolymerized by ethylene and a small amount of α-olefin and has a linear molecular chain structure. LLDPE7042 itself has certain insulation properties, and its molecular chain is relatively regular, which can effectively prevent the migration of charges. When it is filled into the cross-linked polyolefin, it is evenly distributed in the molecular network of the cross-linked polyolefin, further filling the gaps between the molecular chains and reducing the migration channels of free electrons and ions. This is like adding another layer of protection to the original insulation barrier, which significantly improves the insulation resistance of the insulating layer 2. In automotive high-voltage cables, higher insulation resistance means lower leakage risk, which can ensure the stable transmission of current in the conductor 1 and ensure the safe operation of the electrical system.

[0055] Furthermore, the material of the jacket layer 5 in this embodiment is the same as that of the insulation layer 2. The slightly frosted, ultra-flexible cross-linked polyolefin firstly has a slightly frosted appearance, which can prevent slipping during cable processing and wiring harness automation equipment processing. Secondly, the material hardness is 78-80A (the Shore A hardness range of this material), and its ultra-flexible properties can alleviate the problem of increased hardness caused by the self-adhesive aluminum foil 4 being hot-fused to the jacket layer 5. When used with the co-directionally stranded conductor 1, it adapts to the operating environment of the connection, and the conductor has high bending resistance and high flexibility.

[0056] Furthermore, the outer surfaces of the insulating layer 2 and the sheath layer 5 are both frosted to increase surface friction and reduce slippage during processing. For example, during the installation of automotive high-voltage cables, installers need to manually bend, thread, and secure the cables. If the cable surface is smooth, slippage is likely to occur during operation, increasing the difficulty and labor intensity of installation. The frosted cable surface has better anti-slip properties, allowing installers to hold the cable more firmly and perform various operations with ease, improving installation efficiency and quality. Frosting is usually performed using methods such as mechanical grinding, chemical etching, or laser etching. Mechanical grinding involves rubbing abrasive tools such as sandpaper and a grinding wheel against the cable surface to remove some material and form a uniformly rough surface; chemical etching uses specific chemical reagents to react with the cable surface material to selectively dissolve some substances, thereby changing the surface morphology; and laser etching uses a high-energy laser beam to precisely ablate the surface to create the desired rough structure. In actual operation, it is necessary to select appropriate frosting methods and process parameters based on the material, size and subsequent processing requirements of the cable, and no excessive restrictions are imposed here.

[0057] Furthermore, the inner braided layer 3 is woven from tinned copper-clad steel wire. This provides a shielding effect while offering high tensile strength and adaptability to bending conditions. For example, tinned copper-clad steel wire is a composite metal material that combines the mechanical properties of steel wire with the electrical conductivity and protective properties of copper and tin. Its structure consists of: a steel wire core, providing basic mechanical support for the tinned copper-clad steel wire. The steel wire is typically made of high-strength carbon steel, boasting high tensile strength and toughness, capable of withstanding significant tensile and bending stresses; an intermediate layer, a copper layer coated on the surface of the steel wire. Copper has excellent electrical and thermal conductivity, meeting requirements for electrical connections and other aspects. The copper layer also provides a degree of corrosion protection, protecting the steel wire from environmental erosion; and an outer layer, a layer of tin is plated on the surface of the copper layer. Tin is chemically stable and offers excellent corrosion resistance, particularly against air, water, and some weakly acidic and alkaline environments. Furthermore, the tin layer improves the material's weldability, making the tinned copper-clad steel wire easier to handle during welding and resulting in higher-quality solder joints.

[0058] Furthermore, flame-retardant polyester yarn is used to weave the outer braided layer 6. Flame-retardant polyester yarn is a polyester fiber that has been specially modified. It is based on ordinary polyester yarn and has excellent flame-retardant properties by adding flame retardants. Ordinary polyester yarn is easy to burn when exposed to open flame or high temperature, and will continue to burn and release a large amount of heat and smoke, which is extremely dangerous in a vehicle environment. Flame-retardant polyester yarn can inhibit the combustion process to a certain extent, slow down the spread of flames, and reduce the amount of heat and smoke generated by combustion. Weaving flame-retardant polyester yarn into the outer braided layer 6 utilizes the unique advantages of the weaving process. The weaving process can make the fiber yarns intertwine with each other according to a certain pattern, forming a mesh structure with certain strength and flexibility. This structure can not only be tightly wrapped around the cable conductor 1 or the insulating layer 2, but can also be flexibly adjusted according to the shape and size of the cable to ensure a good fit with other parts of the cable.

[0059] Furthermore, a silicone resin is coated on the outer surface of the outer braided layer 6. Silicone resin is a high molecular polymer with a silicon-oxygen bond as the main chain, and its molecular structure contains a large number of organic groups. Silicone resin has extremely high insulation resistance and breakdown voltage. After being coated on the outer surface of the outer braided layer 6, it can further increase the thickness of the insulation layer 2 of the cable and improve the overall insulation performance. The outer braided layer 6 itself may have certain gaps or pores. The silicone resin can fill these tiny defects, reduce leakage channels, thereby reducing the leakage current of the cable and improving the reliability of insulation. In automotive high-voltage cables, good insulation performance is the key to ensuring the safe and stable operation of the electrical system, and can effectively prevent the occurrence of faults such as short circuits and leakage. In terms of coating process, methods such as dipping, spraying or brushing are usually used to evenly cover the outer surface of the outer braided layer 6 with silicone resin to form a continuous and dense protective film. Silicone resin has excellent hydrophobicity, and the organic groups in its molecular structure can repel moisture. After the outer surface of the outer braided layer 6 is coated with silicone resin, a hydrophobic film can be formed to prevent moisture from penetrating into the interior of the cable. Moisture is one of the important factors that lead to the degradation of cable insulation performance and electrical failure, especially in a humid environment. The hydrophobicity of silicone resin can effectively reduce the impact of moisture on the cable, improve the moisture resistance of the cable, and extend the service life of the cable in a humid environment. During use, vehicles will be exposed to the outdoor environment for a long time and will be affected by natural factors such as sunlight, ultraviolet rays, ozone, wind and rain. Silicone resin has good weather resistance, can resist ultraviolet radiation and ozone erosion, and is not prone to aging, discoloration and performance degradation. It can protect the outer braided layer 6 and the internal structure of the cable from damage by the natural environment, ensure that the cable maintains stable performance during long-term use, and reduce the maintenance and replacement costs caused by environmental factors.

[0060] This embodiment also provides a vehicle high-voltage cable, which is manufactured using the above-mentioned vehicle high-voltage cable manufacturing method. Figure 2 Combine Figure 3 As shown, the automotive high-voltage cable includes, from the inside out, a conductor 1, an insulating layer 2, an inner braided layer 3, an aluminum foil 4, a sheath layer 5, and an outer braided layer 6. The AL layer 41 in the aluminum foil 4 is 15 μm thick. The aluminum foil 4 uses a single-sided hot-melt self-adhesive aluminum foil 4. From the inside out, the aluminum foil 4 includes an AL layer 41, a PET layer 42, and a GLUE layer 43. The GLUE layer 43 is hot-melted and bonded to the sheath layer 5. The thickness of the aluminum layer is increased from 9 μm to 15 μm, and the hot-melt adhesive is adsorbed on the outside of the PET layer 42. During the extrusion process of the sheath layer 5, the plasticizing temperature of the material and the extrusion pressure of the die are used to achieve a tight fit between the cable's sheath layer 5 and the aluminum foil 4. At the same time, due to the increased thickness of the metal aluminum layer in the aluminum foil 4, the cable's ability to shield high-frequency signals can be improved, and its anti-interference ability is stronger.

[0061] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for preparing a high-voltage cable for a vehicle, characterized in that: The following steps are involved: S1. A conductor (1) is formed by a three-layer twisting method, wherein the twisting direction of the three-layer structure of the conductor (1) from the inside to the outside is all left-hand; S2. forming an insulating layer (2) on the outer wall surface of the conductor (1) by extrusion; S3, forming an inner braided layer (3) on the outer wall surface of the insulating layer (2) using a braiding machine; S4, an aluminum foil (4) formed by a composite of an AL layer (41), a PET layer (42) and a GLUE layer (43) is spirally wound on the outer wall surface of the inner braided layer (3), wherein the GLUE layer (43) of the aluminum foil (4) is a hot-melt polyurethane adhesive; S5, forming a sheath layer (5) on the outer wall surface of the aluminum foil (4) by extrusion, and bonding the GLUE layer (43) of the aluminum foil (4) to the sheath layer (5); S6. Using the braiding machine, form an outer braided layer (6) on the outer wall surface of the sheath layer (5).

2. The method for preparing a high-voltage cable for a vehicle according to claim 1, wherein: In step S1, the three-layer structure of the conductor (1) includes a first layer structure, a second layer structure and a third layer structure, the first layer structure includes one strand, the second layer structure includes six strands, and the twisting direction of the six strands is left-twisted, the third layer structure includes twelve strands, and the twisting direction of the twelve strands is left-twisted, each strand includes a plurality of wires, and the twisting direction of the plurality of wires is left-twisted.

3. The method for preparing a high-voltage cable for a vehicle according to claim 1, wherein: The material of the insulating layer (2) is cross-linked polyolefin.

4. The method for preparing a high-voltage cable for a vehicle according to claim 3, characterized in that: The cross-linked polyolefin is filled with LLDPE7042.

5. The method for preparing a high-voltage cable for a vehicle according to claim 4, characterized in that: The material of the sheath layer (5) is the same as that of the insulation layer (2).

6. The method for preparing a high-voltage cable for a vehicle according to claim 5, characterized in that: The outer surfaces of the insulating layer (2) and the sheath layer (5) are both frosted.

7. The method for preparing a high-voltage cable for a vehicle according to claim 1, characterized in that: In the step S3, tinned copper-clad steel wire is used to weave the inner braided layer (3).

8. The method for preparing a high-voltage cable for a vehicle according to claim 1, wherein: The outer braided layer (6) is woven with flame-retardant polyester yarn.

9. The method for preparing a high-voltage cable for a vehicle according to claim 8, characterized in that: An organic silicon resin is coated on the outer surface of the outer braided layer (6).

10. High voltage cable for vehicle, characterized in that: The vehicle high-voltage cable is manufactured using the method for preparing a vehicle high-voltage cable according to any one of claims 1 to 9, wherein the vehicle high-voltage cable comprises, from the inside to the outside, a conductor (1), an insulating layer (2), an inner braided layer (3), an aluminum foil (4), a sheath layer (5) and an outer braided layer (6), wherein the thickness of the Al layer (41) in the aluminum foil (4) is 15 μm.

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