A new energy vehicle aluminum high-voltage shielded cable with a sheath and a processing method thereof

Abstract

The application relates to the technical field of high-voltage cables for new energy vehicles, and relates to an aluminum-bar high-voltage shielding cable with a sheath for new energy vehicles and a processing method, which comprises, from inside to outside, a flat aluminum alloy conductor, a high-temperature-resistant insulation layer, an aluminum metal shielding layer and a sheath layer; the flat aluminum alloy conductor is integrally fused and extruded by 6-series aluminum alloy; the insulation layer is a low-smoke halogen-free silane cross-linking material; the shielding layer is a seamless closed-loop structure of pure aluminum which is integrally and fully coated by fusion continuous extrusion; and the sheath layer is a polydodecanolactam material. The application realizes 100% shielding coverage, the shielding effectiveness is greater than or equal to 90 dB, the bending life is improved by more than 3 times, the problems of bending, bulging and layering of the shielding layer and oxidation of the shielding layer are completely solved, and the application is suitable for high-voltage power distribution scenes of new energy vehicles.

Description

Technical Field

[0001] This invention relates to the field of high-voltage cable technology for new energy vehicles, and in particular to a sheathed aluminum busbar high-voltage shielded cable for new energy vehicles and its processing method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the high-voltage power distribution system for vehicles places higher demands on the electromagnetic compatibility, mechanical reliability, and lightweight design of cables. Aluminum busbar cables, with their excellent conductivity and lightweight advantages, are widely used in the high-voltage power distribution field of new energy vehicles. However, the shielding layers of existing aluminum busbar cables mostly use aluminum foil winding or aluminum wire braiding structures, resulting in seams and overlaps, leading to insufficient shielding coverage and severe electromagnetic leakage under high-frequency conditions, affecting the normal operation of on-board electronic equipment. Furthermore, aluminum foil winding shielding layers are prone to bulging and delamination under repeated bending conditions, while aluminum wire braiding shielding layers are susceptible to oxidation and corrosion, resulting in significant attenuation of shielding effectiveness after long-term use. In terms of manufacturing processes, traditional segmented winding and overlapping welding methods for shielding layers are difficult to implement for continuous production, resulting in low production efficiency and poor consistency. Therefore, how to provide an aluminum busbar shielded cable with high shielding coverage and excellent bending performance, achieving continuous and stable production, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0003] The technical problem to be solved by this invention is that: the shielding layer of existing aluminum busbar cables mostly adopts aluminum foil winding or aluminum wire braiding structure, which has seams and overlap gaps, insufficient shielding coverage, and serious electromagnetic leakage under high frequency conditions; the shielding layer is prone to bulging, delamination or oxidation corrosion under repeated bending conditions, and the shielding effectiveness decays with long-term use; traditional processing methods are difficult to achieve continuous production, resulting in low efficiency and poor consistency.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: a sheathed aluminum busbar high-voltage shielded cable for new energy vehicles, comprising a flat aluminum alloy conductor, a high-temperature resistant insulation layer, an aluminum metal shielding layer, and a sheathing layer, which are coaxially wrapped from the inside to the outside; the flat aluminum alloy conductor is an integral structure formed by integral melting and extrusion of 6-series aluminum alloy, and its two sides along the length direction are smoothly transitioned arc-shaped curved surfaces; the high-temperature resistant insulation layer is a low-smoke halogen-free silane cross-linked material integrally extruded and wrapped on the outer surface of the flat aluminum alloy conductor; the aluminum metal shielding layer is pure aluminum integrally melted and continuously extruded at high temperature and fully wrapped on the outer surface of the high-temperature resistant insulation layer, forming a closed-loop structure without joints or overlaps, and tightly bonded to the high-temperature resistant insulation layer without gaps; the sheathing layer is polydodecyl lactam material integrally extruded and wrapped on the outer surface of the aluminum metal shielding layer.

[0005] Furthermore, the width of the flat aluminum alloy conductor is 20mm-35mm, the thickness is 1.4mm-6.3mm, and the width-to-thickness ratio is 5:1~12:1.

[0006] Furthermore, the radius of curvature of the arc-shaped surface structure on both sides of the flat aluminum alloy conductor is equal to 1 / 2 of the thickness of the flat aluminum alloy conductor, and the four corners of the flat aluminum alloy conductor are provided with rounded transitions, with the radius of the rounded corners being equal to 1.5 times the thickness of the high-temperature resistant insulation layer.

[0007] Furthermore, the flat aluminum alloy conductor is made by melt extrusion of 6063-T5 aluminum alloy rod, and its surface is plasma treated, with a surface roughness Ra of 0.8μm-1.2μm.

[0008] Furthermore, the thickness of the high-temperature resistant insulation layer is 0.5mm-1.0mm, the Shore hardness is 82HA-88HA, and the degree of crosslinking is ≥85%.

[0009] Furthermore, the thickness of the aluminum metal shielding layer is 0.5mm-1.0mm, the difference in Shore hardness between it and the high-temperature resistant insulation layer is ≤12HA, and the interlayer gap between it and the high-temperature resistant insulation layer is ≤0.01mm.

[0010] Furthermore, the thickness of the sheath layer is 0.3mm-0.8mm, and the Shore hardness is 75HA-82HA, with a Shore hardness difference of ≤10HA between it and the aluminum metal shielding layer; the difference in the coefficients of thermal expansion between the flat aluminum alloy conductor, the aluminum metal shielding layer, and the sheath layer is ≤4×10⁻⁶. -6 / ℃.

[0011] Furthermore, the processing method includes the following steps: Step S1, Conductor forming: Using a continuous extrusion device, the 6-series aluminum alloy rod is melted and extruded at 460℃-490℃ to form a flat aluminum alloy conductor with arc-shaped curved surface structure on both sides. The surface of the formed flat aluminum alloy conductor is subjected to plasma treatment to adjust its surface roughness Ra to 0.8μm-1.2μm. Step S2, insulation layer extrusion: Low smoke halogen-free silane crosslinking material is melt-extruded at 170℃-180℃ using a plastic extruder and integrally coated on the outer surface of the flat aluminum alloy conductor. It is then crosslinked and cured with warm water to form a high-temperature resistant insulation layer. Step S3, Integrated shielding layer coating: After the high-temperature resistant insulation layer is cross-linked and the temperature is maintained at 60℃-80℃ under residual heat, the pure aluminum rod is immediately melted and extruded through the aluminum coating equipment, and continuously extruded to fully coat the outer surface of the high-temperature resistant insulation layer, forming a seamless aluminum metal shielding layer that is closely bonded to the high-temperature resistant insulation layer without gaps. Step S4, sheath extrusion: Polydodecyl lactam material is melted and extruded through a plastic extruder and integrally coated on the outer surface of the aluminum metal shielding layer. After cooling and shaping, the sheath layer is formed, and the finished cable is obtained.

[0012] Furthermore, in step S2, the temperature for warm water crosslinking is 90℃, the crosslinking time is 3h-5h, and after the crosslinking is completed, the degree of crosslinking of the high-temperature resistant insulation layer is detected online to be ≥85%.

[0013] Furthermore, in step S3, the heating temperature of the main mold cavity of the aluminum cladding equipment is 500℃, and the mold preheating temperature is 480℃-520℃; the synchronization ratio between the extrusion speed and the insulation layer extrusion speed in step S2 is 1:1.02, the drawing force is controlled at 500N-800N, and segmented air cooling is adopted after extrusion, with a cooling rate of 10℃ / s-15℃ / s.

[0014] Furthermore, in step S4, the extrusion temperature of the polydodecanoic acid material is 220℃-240℃, and after extrusion, gradient cooling is used for shaping. The peel force between the sheath layer and the aluminum metal shielding layer after cooling is ≥15N / 10mm.

[0015] The beneficial effects of this invention are: (1) The present invention uses pure aluminum to form an aluminum metal shielding layer by continuous extrusion at high temperature to form a whole-body shielding layer. It is a closed-loop structure without seams or overlaps, achieving 100% shielding coverage and shielding effectiveness ≥90dB. It completely eliminates the electromagnetic leakage caused by the seam gaps of traditional winding and braiding shielding layers, while avoiding the problems of bending, bulging, delamination and shielding layer oxidation.

[0016] (2) The present invention adopts a flat aluminum alloy conductor formed by integral melt extrusion of 6 series aluminum alloy, with arc-shaped curved surface structure on both sides. Combined with the design of insulation layer, shielding layer and sheath layer with Shore hardness gradient matching, and precise matching of thermal expansion coefficient of each layer, the bending life is increased by more than 3 times, which significantly improves the long-term reliability of the cable in the high voltage power distribution system of new energy vehicles.

[0017] (3) The present invention provides a continuous processing method. Through a four-step continuous process of conductor forming → insulation layer extrusion → shielding layer integral coating → sheath layer extrusion, the shielding layer coating under residual heat and the precise synchronous control of the speed of each process are utilized to achieve efficient and consistent fully automated continuous production. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of a sheathed aluminum busbar high-voltage shielded cable for new energy vehicles in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the processing technology of a sheathed aluminum busbar high-voltage shielded cable for new energy vehicles in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures: 100. Flat aluminum alloy conductor; 200. High-temperature resistant insulation layer; 300. Aluminum metal shielding layer; 400. Sheath layer. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Figure 1 The diagram illustrates a sheathed high-voltage shielded aluminum busbar cable for new energy vehicles, comprising, from the inside out, a flat aluminum alloy conductor 100, a high-temperature resistant insulation layer 200, an aluminum metal shielding layer 300, and a sheath layer 400, coaxially wrapped from the inside out. The flat aluminum alloy conductor 100 is a one-piece structure formed by integral melting and extrusion of 6-series aluminum alloy, serving as the current-carrying core of the cable. Its two edges along its length are smoothly transitioned arc-shaped surfaces to avoid stress concentration at right-angled edges during insulation extrusion and bending. The high-temperature resistant insulation layer 200 is a low-smoke, halogen-free silane cross-linked material integrally extruded and coated onto the outer surface of the flat aluminum alloy conductor 100, providing insulation and high-temperature protection. The aluminum metal shielding layer 300 is pure aluminum integrally melted and continuously extruded at high temperatures, fully covering the outer surface of the high-temperature resistant insulation layer 200. It is a seamless, non-overlapping closed-loop structure, tightly bonded to the high-temperature resistant insulation layer 200 without gaps, providing fully enclosed electromagnetic shielding. The sheath layer 400 is made of polydodecyl lactam material and is integrally extruded and coated on the outer surface of the aluminum metal shielding layer 300 to provide outer mechanical protection and weather protection.

[0025] The flat aluminum alloy conductor 100 has a width of 20mm-35mm and a thickness of 1.4mm-6.3mm, with a width-to-thickness ratio of 5:1 to 12:1. Its flat design accommodates the narrow installation space of new energy vehicles while increasing the heat dissipation area. The radius of curvature of the curved surface structure on both sides of the flat aluminum alloy conductor 100 is equal to half the thickness of the conductor. All four corners are rounded, with a radius equal to 1.5 times the thickness of the high-temperature resistant insulation layer 200, ensuring uniform insulation coverage without weak points. The flat aluminum alloy conductor 100 is preferably made from 6063-T5 aluminum alloy rod through melt extrusion. Its surface is plasma-treated, with a surface roughness Ra controlled at 0.8μm-1.2μm to enhance adhesion to the insulation layer.

[0026] The high-temperature resistant insulation layer 200 has a thickness of 0.5mm-1.0mm, a Shore hardness of 82HA-88HA, and a crosslinking degree of ≥85%. After being crosslinked and cured in warm water, the low-smoke, halogen-free silane crosslinking material exhibits excellent high-temperature resistance, electrical insulation, and flexibility, meeting the insulation requirements of high-voltage cables for new energy vehicles.

[0027] The aluminum metal shielding layer 300 has a thickness of 0.5mm-1.0mm, and its Shore hardness difference with that of the high-temperature resistant insulation layer 200 is ≤12HA. The interlayer gap between the aluminum metal shielding layer 300 and the high-temperature resistant insulation layer 200 is ≤0.01mm. The closed-loop shielding structure, formed by continuous high-temperature melting and extrusion of pure aluminum into a single, fully encapsulated layer, eliminates the seams and overlaps of traditional winding and braiding shielding layers, achieving 100% shielding coverage and a shielding effectiveness ≥90dB. The shielding layer is immediately encapsulated after the high-temperature resistant insulation layer 200 has completed cross-linking and while maintaining a residual heat of 60℃-80℃. This residual heat promotes interfacial fusion between the shielding layer and the insulation layer, forming a gapless, tightly bonded structure, effectively preventing delamination and bulging during bending.

[0028] The thickness of the sheath layer 400 is 0.3mm-0.8mm, and its Shore hardness is 75HA-82HA, with a Shore hardness difference of ≤10HA between it and the aluminum metal shielding layer 300. The difference in the coefficients of thermal expansion between the flat aluminum alloy conductor 100, the aluminum metal shielding layer 300, and the sheath layer 400 is ≤4×10⁻⁶. -6 / ℃. The sheath layer is made of polydodecanoic acid (PA12) material, which has excellent chemical corrosion resistance, abrasion resistance and low-temperature toughness. The precise matching of Shore hardness and coefficient of thermal expansion between each layer reduces the interfacial stress between layers under temperature changes and mechanical loads, significantly improving the bending life of the cable.

[0029] Figure 2The process flow of the present invention is shown. The processing method includes the following steps: Step S1, conductor forming: using a continuous extrusion device, a 6-series aluminum alloy rod is melted and extruded at 460℃-490℃ to form a flat aluminum alloy conductor 100 with arc-shaped curved surface structure on both sides; the surface of the formed flat aluminum alloy conductor 100 is subjected to plasma treatment to adjust its surface roughness Ra to 0.8μm-1.2μm; Step S2, insulation layer extrusion: using a plastic extruder, a low-smoke halogen-free silane crosslinking material is melted and extruded at 170℃-180℃, integrally coated on the outer surface of the flat aluminum alloy conductor 100, and cured by warm water crosslinking to form a high-temperature resistant insulation layer 200; the temperature of warm water crosslinking is 90℃, the crosslinking time is 3h-5h, and the crosslinking degree is ≥85% after the crosslinking is completed; Step S3, shielding layer integral coating: after the high-temperature resistant insulation layer 200 is crosslinked and the temperature is maintained at 60℃-80℃ under residual heat, the shielding layer is integrally coated with a high-temperature resistant insulation layer 200. The process involves: 1) Molten aluminum rods are extruded using an aluminum cladding machine and continuously extruded to fully cover the outer surface of the high-temperature insulation layer 200, forming a seamless aluminum metal shielding layer 300 that adheres perfectly to the high-temperature insulation layer 200. 2) The main mold cavity heating temperature of the aluminum cladding machine is 500℃, and the mold preheating temperature is 480℃-520℃. 3) The extrusion speed is synchronized with the insulation extrusion speed in step S2 by a ratio of 1:1.02, and the pull-out force is controlled at 500N-800N. 4) After extrusion, segmented air cooling is used, with a cooling rate of 10℃ / s-15℃ / s. 5) In step S4, the sheath layer is extruded: Polydodecylamide material is melted and extruded at 220℃-240℃ using a plastic extruder and integrally covered onto the outer surface of the aluminum metal shielding layer 300. After gradient cooling and shaping, the sheath layer 400 is formed. After cooling, the peel force between the sheath layer 400 and the aluminum metal shielding layer 300 is ≥15N / 10mm, resulting in the finished cable.

[0030] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A sheathed aluminum busbar high-voltage shielded cable for new energy vehicles, characterized in that: The device comprises, from the inside out, a flat aluminum alloy conductor (100), a high-temperature resistant insulation layer (200), an aluminum metal shielding layer (300), and a sheath layer (400), which are coaxially wrapped together. The flat aluminum alloy conductor (100) is an integral structure formed by integral melting and extrusion of 6-series aluminum alloy, and its two sides along the length direction are arc-shaped curved surfaces with smooth transitions. The high-temperature resistant insulation layer (200) is a low-smoke halogen-free silane cross-linked material integrally extruded and wrapped around the outer surface of the flat aluminum alloy conductor (100). The aluminum metal shielding layer (300) is pure aluminum integrally melted and continuously extruded and fully wrapped around the outer surface of the high-temperature resistant insulation layer (200), forming a closed-loop structure without seams or overlaps, and is tightly fitted to the high-temperature resistant insulation layer (200) without gaps. The sheath layer (400) is polydodecanoic acid material integrally extruded and wrapped around the outer surface of the aluminum metal shielding layer (300).

2. The sheathed aluminum busbar high-voltage shielded cable for new energy vehicles according to claim 1, characterized in that: The flat aluminum alloy conductor (100) has a width of 20mm-35mm and a thickness of 1.4mm-6.3mm, with a width-to-thickness ratio of 5:1 to 12:

1. The flat aluminum alloy conductor (100) is made by melting and extruding 6063-T5 aluminum alloy rod. The radius of curvature of the arc-shaped curved surface structure on both sides of its length direction is equal to 1 / 2 of the thickness of the flat aluminum alloy conductor (100). The four corners are provided with rounded transitions, and the radius of the rounded corners is equal to 1.5 times the thickness of the high-temperature resistant insulation layer (200). The surface of the flat aluminum alloy conductor (100) is plasma treated, and the surface roughness Ra is 0.8μm-1.2μm.

3. The sheathed aluminum busbar high-voltage shielded cable for new energy vehicles according to claim 1, characterized in that: The high-temperature resistant insulation layer (200) has a thickness of 0.5mm-1.0mm, a Shore hardness of 82HA-88HA, and a crosslinking degree of ≥85%.

4. The sheathed aluminum busbar high-voltage shielded cable for new energy vehicles according to claim 1, characterized in that: The aluminum metal shielding layer (300) has a thickness of 0.5mm-1.0mm, and the difference between its Shore hardness and that of the high-temperature resistant insulation layer (200) is ≤12HA. The interlayer gap between the aluminum metal shielding layer (300) and the high-temperature resistant insulation layer (200) is ≤0.01mm.

5. A sheathed aluminum busbar high-voltage shielded cable for new energy vehicles, characterized in that: The thickness of the sheath layer (400) is 0.3mm-0.8mm, and the Shore hardness is 75HA-82HA, with a Shore hardness difference of ≤10HA between it and the aluminum metal shielding layer (300); the difference in the coefficients of thermal expansion between the flat aluminum alloy conductor (100), the aluminum metal shielding layer (300), and the sheath layer (400) is ≤4×10⁻ 6 / ℃.

6. A method for processing a sheathed aluminum busbar high-voltage shielded cable for new energy vehicles, characterized in that: The method for preparing the sheathed aluminum busbar high-voltage shielded cable for new energy vehicles according to any one of claims 1 to 5 includes the following steps: Step S1, conductor forming: Using a continuous extrusion device, the 6-series aluminum alloy rod is melted and extruded at 460℃-490℃ to form a flat aluminum alloy conductor (100) with arc-shaped curved surface structure on both sides; the surface of the formed flat aluminum alloy conductor (100) is subjected to plasma treatment to adjust its surface roughness Ra to 0.8μm-1.2μm; Step S2, insulation layer extrusion: The low-smoke halogen-free silane crosslinking material is melt-extruded at 170℃-180℃ using a plastic extruder and integrally coated on the outer surface of the flat aluminum alloy conductor (100). It is then crosslinked and cured with warm water to form a high-temperature resistant insulation layer (200). Step S3, shielding layer integral coating: After the high temperature resistant insulation layer (200) is cross-linked and the temperature is maintained at 60℃-80℃ under residual heat, the pure aluminum rod is immediately melted and extruded through the aluminum coating equipment, and integrally and continuously extruded to fully coat the outer surface of the high temperature resistant insulation layer (200), forming a seamless aluminum metal shielding layer (300) that is bonded to the high temperature resistant insulation layer (200) without gaps. Step S4, extrusion of the sheath layer: Polydodecyl lactam material is melted and extruded through a plastic extruder and integrally coated on the outer surface of the aluminum metal shielding layer (300). After cooling and shaping, the sheath layer (400) is formed, and the finished cable is obtained.

7. A method for processing a sheathed aluminum busbar high-voltage shielded cable for new energy vehicles according to claim 6, characterized in that: In step S2, the temperature for warm water crosslinking is 90℃, the crosslinking time is 3h-5h, and after crosslinking is completed, the degree of crosslinking of the high-temperature resistant insulation layer (200) is tested online to be ≥85%; In step S3, the heating temperature of the main mold cavity of the aluminum cladding equipment is 500℃, the mold preheating temperature is 480℃-520℃, the synchronization ratio of the extrusion speed and the extrusion speed of the insulation layer in step S2 is 1:1.02, the pull force is controlled at 500N-800N, and segmented air cooling is adopted after extrusion, with a cooling rate of 10℃ / s-15℃ / s; In step S4, the extrusion temperature of the polydodecylamide material is 220℃-240℃, and gradient cooling is adopted after extrusion. The peel force between the cooled sheath layer (400) and the aluminum metal shielding layer (300) is ≥15N / 10mm.

Images