High current high temperature resistant in-vehicle high voltage aluminum wire

Abstract

The application relates to the technical field of electric wires, and provides high-load high-temperature-resistant high-voltage aluminum wire in a vehicle, which comprises a conductor, a flexible aluminum alloy conductor formed by twisting a plurality of aluminum alloy filaments, a wrapping constraint layer arranged at the outer periphery of the conductor, and a silicone rubber insulation layer wrapped outside the wrapping constraint layer, wherein the wrapping constraint layer is wrapped at the outer periphery of the conductor and forms a continuous ring constraint structure, the ring constraint structure exerts a radial compression constraint action on the conductor, when a filament inside the conductor breaks, the ring constraint structure is used for limiting the migration of the broken filament to the outer periphery of the conductor, the broken filament is kept in the internal area of the conductor bundle, and thus the risk of the broken filament piercing into the silicone rubber insulation layer is reduced.

Description

Technical Field

[0001] This invention relates to the field of wire technology, and more specifically to high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for automotive applications. Background Technology

[0002] In high-voltage wiring harnesses of new energy vehicles, Category 5 or Category 6 flexible aluminum alloy conductors are widely used as conductive cores to reduce the weight of the vehicle and improve flexibility.

[0003] Because the five types of flexible aluminum conductors are formed by twisting together a large number of fine-diameter aluminum monofilaments, some of the aluminum monofilaments are prone to breakage during conductor twisting, winding, transportation, installation bending, and long-term vibration.

[0004] The broken ends of aluminum monofilaments usually form sharp fractures.

[0005] Silicone rubber is commonly used as the insulation material in high-voltage cables for new energy vehicles. Although silicone rubber has excellent high-temperature resistance and flexibility, its puncture resistance is relatively low.

[0006] When there is a broken wire inside the conductor, the end of the broken wire may protrude outward during vibration, bending or thermal cycling, and gradually compress or even penetrate into the silicone rubber insulation layer, thus forming a local insulation defect, which may lead to insulation breakdown in severe cases.

[0007] In the prior art, in order to improve the quality of silicone rubber insulation layer, a high-temperature continuous vulcanization process is usually used for insulation extrusion production.

[0008] During the vulcanization process, the cable needs to pass through a high-temperature vulcanization zone of several hundred degrees Celsius.

[0009] Conventional polyester tape, non-woven tape, PVC tape and other wrapping materials are prone to melting, shrinkage or deterioration of mechanical properties under high temperature vulcanization conditions, making it difficult to maintain the constraint on the conductor throughout the entire vulcanization process.

[0010] Therefore, how to effectively constrain flexible aluminum conductors without affecting the high-temperature vulcanization process of silicone rubber, and suppress the outward protrusion of broken wires and damage to the insulation layer, has become a technical problem that urgently needs to be solved in this field. To this end, we propose a high-current-carrying, high-temperature resistant, high-voltage aluminum wire for in-vehicle use. Summary of the Invention

[0011] In view of the shortcomings of the prior art, the present invention provides a high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for in-vehicle use, which overcomes the shortcomings of the prior art, has a reasonable design, a compact structure, and solves the problems mentioned in the background art.

[0012] To achieve the above objectives, the present invention provides the following technical solution: High-current-carrying, high-temperature-resistant, high-voltage aluminum wires for automotive applications, including: The conductor is a flexible aluminum alloy conductor formed by twisting together multiple aluminum alloy monofilaments. A wrapping constraint layer is disposed on the outer periphery of the conductor; A silicone rubber insulating layer is wrapped around the outside of the wrapping constraint layer; in, A wrapping constraint layer is wrapped around the outer periphery of the conductor to form a continuous circumferential constraint structure, which applies radial compressive constraint to the conductor. When a single filament inside the conductor breaks, the circumferential constraint structure is used to restrict the broken filament from migrating to the outer periphery of the conductor bundle, keeping the broken filament inside the conductor bundle and thus reducing the risk of the broken filament piercing the silicone rubber insulation layer.

[0013] Preferably, the conductor is a Class 5 flexible aluminum alloy conductor or a Class 6 flexible aluminum alloy conductor.

[0014] Preferably, the wrapping constraint layer is formed by wrapping with polytetrafluoroethylene tape.

[0015] Preferably, the thickness of the polytetrafluoroethylene tape is 0.03 to 0.12 mm.

[0016] Preferably, the polytetrafluoroethylene tape is wrapped around the outer periphery of the conductor in a spiral manner, with an overlap rate of 30% to 70%.

[0017] Preferably, the polytetrafluoroethylene tape adopts a double-layer reverse wrapping structure to form a wrapping constraint layer.

[0018] Preferably, the silicone rubber insulating layer is formed by cold-feed extrusion and then cross-linked and cured by continuous high-temperature vulcanization.

[0019] Preferably, the continuous vulcanization temperature is 300℃~850℃, and the wrapping constraint layer maintains a radial constraint effect on the conductor during the vulcanization process.

[0020] A method for preparing high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for automotive applications, characterized by comprising the following steps: S1. Provide flexible aluminum alloy conductors; S2. A wrapping constraint layer is formed around the outer periphery of the conductor, and the wrapping constraint layer forms a continuous circumferential constraint structure. S3. Extrude a silicone rubber insulating layer on the outside of the wrapping constraint layer; S4. The extruded cable is fed into a high-temperature vulcanizing device for continuous vulcanization. in, The wrapping constraint layer maintains a continuous radial compressive constraint on the conductor during the vulcanization process to limit the outward migration of broken monofilaments inside the conductor.

[0021] Preferably, in step S2, polytetrafluoroethylene (PTFE) tape is used for wrapping, and the PTFE tape is pre-tightened on the outer periphery of the conductor by wrapping tension to construct a continuously existing radial compression constraint structure. This invention provides a high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for automotive applications. It offers the following advantages: This invention provides a polytetrafluoroethylene (PTFE) wrapping constraint layer around the flexible aluminum alloy conductor and utilizes the wrapping tension to form a continuous radial compression constraint structure. This radial compression constraint structure can continuously wrap and constrain the conductor bundle. When a broken wire occurs inside the conductor, it can limit the migration of the broken wire to the outer periphery, thereby reducing the probability of the broken wire turning outward and solving the problem that broken wires in existing flexible aluminum conductors tend to protrude outward.

[0022] This invention provides a wrapping constraint layer located between the conductor and the silicone rubber insulation layer. This allows the broken wire to be confined within the conductor bundle by a radial constraint structure, thereby reducing the possibility of direct contact between the broken wire and the silicone rubber insulation layer, reducing the risk of the broken wire penetrating the insulation layer and forming local defects, and improving the long-term reliability of the insulation structure.

[0023] This invention uses polytetrafluoroethylene (PTFE) to construct the wrapping constraint layer. PTFE can maintain structural integrity and mechanical stability during the high-temperature continuous vulcanization process of silicone rubber, and is not prone to melting, shrinkage, or failure. This ensures that the wrapping constraint layer maintains radial constraint throughout the entire vulcanization stage, solving the problem that conventional polyester tape, non-woven tape, and PVC tape cannot adapt to high-temperature vulcanization processes.

[0024] This invention not only utilizes polytetrafluoroethylene (PTFE) as the isolation medium between the conductor and the insulation layer, but also constructs a continuous radial compression constraint structure through PTFE wrapping to control the trajectory of the broken wire, transforming the broken wire from a free outward expansion state to a restricted state. This forms a failure suppression mechanism in which the broken wire remains inside the conductor bundle, thereby improving the insulation safety and operational reliability of high-voltage wiring harnesses in new energy vehicles.

[0025] The radial compression constraint structure constructed in this invention runs through the entire process of conductor manufacturing, insulation extrusion, high-temperature vulcanization and vehicle use. It can continue to exert a constraint effect under long-term vibration, thermal cycling and repeated bending conditions, which helps to reduce the risk of insulation breakdown and improve the service life and service stability of high-voltage cables. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the preparation process of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, what is described is only a part of this invention, not all of it. All other works obtained by those skilled in the art based on this invention without inventive effort are within the scope of protection of this invention.

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0030] Example 1 High-current-carrying, high-temperature-resistant, high-voltage aluminum wire for automotive applications, comprising a conductor, a wrapping constraint layer, and an insulation layer.

[0031] The conductor adopts a Class 5 flexible aluminum alloy conductor structure. The conductor is formed by regularly twisting multiple aluminum alloy monofilaments. The diameter of the aluminum monofilament is 0.08 to 0.30 mm. The conductor cross-sectional area can be selected according to the application requirements, such as 25 mm², 35 mm², 50 mm², 70 mm², 95 mm² or 120 mm².

[0032] In this embodiment, a wrapping constraint layer is provided around the outer periphery of the conductor. The wrapping constraint layer is formed by wrapping polytetrafluoroethylene (PTFE) tape, the thickness of which is preferably 0.03–0.10 mm. The wrapping method can be helical wrapping, with an overlap rate of 30%–70%. Through continuous wrapping, the PTFE tape covers the outer periphery of the conductor and forms a complete encapsulation structure. A constant tension is maintained during the wrapping process. After being subjected to tension, the PTFE tape covers the outer surface of the conductor, thereby forming a continuous circumferential constraint structure. This circumferential constraint structure applies radial compression to the outer periphery of the conductor. The process involves using a cold-feed extrusion device to extrude a silicone rubber insulation layer onto the outside of the wrapping constraint layer. The insulation layer thickness is preferably 0.8–2.5 mm. The insulation material can be silicone rubber with a heat resistance rating of 180℃, 200℃, or 220℃. After the silicone rubber is extruded, it enters a continuous vulcanization production line, preferably using an infrared continuous vulcanization process. The vulcanization temperature is preferably 300℃–850℃. In actual production, the cable needs to pass through multiple high-temperature vulcanization zones in sequence, and the conductor, wrapping layer, and silicone rubber insulation layer are all in a high-temperature environment at the same time.

[0033] Polytetrafluoroethylene (PTFE) materials have excellent thermal stability and can maintain their integrity during the vulcanization process, while maintaining the circumferential constraint formed by the wrapping, thereby continuously applying radial constraint to the outer periphery of the conductor throughout the vulcanization stage.

[0034] Furthermore, during the vulcanization stage, the conductor temperature rises rapidly. Due to the large thermal expansion coefficient of the aluminum alloy conductor, the original stranding stress inside the conductor is gradually released. Some defective single filaments may break during this process. At the same time, the silicone rubber insulation layer has not yet been fully cross-linked and cured.

[0035] During long-term production, the applicant discovered that after a broken wire occurs inside the flexible aluminum conductor, the broken wire does not remain at the fracture location indefinitely. Instead, under residual stress release, thermal cycling, and vibration, it tends to migrate towards the outer periphery of the conductor. The applicant further discovered that the key factor leading to insulation failure is not the number of broken wires themselves, but rather the radial migration behavior of the broken wires after they form. If a broken filament protrudes outward, it may directly penetrate into the interior of an incompletely cured insulation layer. Such defects are difficult to detect through visual inspection once they are formed.

[0036] In this embodiment, the polytetrafluoroethylene wrapping constraint layer maintains its complete structure during high-temperature vulcanization. When the broken monofilament attempts to turn outward, it is first blocked by the wrapping constraint layer. The broken monofilament is confined to the internal region of the conductor bundle, and its movement trajectory changes from the original free outward expansion state to a restricted state, thereby reducing the possibility of the broken monofilament contacting the silicone rubber insulation layer.

[0037] Furthermore, during the long-term operation of the vehicle, the cable needs to withstand continuous vibration, periodic bending, and temperature cycling. After being excited by vibration, the broken single filament still has the tendency to migrate outward. However, the wrapping constraint layer continues to exist between the conductor and the insulation layer. Therefore, even if the broken single filament is displaced, it is difficult to break through the wrapping constraint layer, thereby achieving continuous restriction on the movement trajectory of the broken filament.

[0038] In this embodiment, the polytetrafluoroethylene wrapping layer not only serves as an isolation layer between the conductor and the insulating layer, but more importantly, it forms a persistent radial constraint structure.

[0039] This radial constraint structure is used throughout the entire process of conductor manufacturing, insulation extrusion, high-temperature vulcanization and vehicle use. By restricting the radial migration path of broken monofilaments, it keeps the broken monofilaments in the internal region of the conductor bundle, thereby reducing the risk of insulation failure caused by broken monofilaments piercing the insulation layer.

[0040] Example 2 This embodiment is basically the same as Embodiment 1.

[0041] The difference is: The polytetrafluoroethylene tape adopts a double-layer reverse wrapping structure.

[0042] The first layer is wrapped in a clockwise direction, and the second layer is wrapped in a counterclockwise direction. The two layers of wrapping overlap each other, thus forming a more stable circumferential constraint structure. The double-layer structure can further improve the overall stability and anti-loosening ability of the wrapping layer. When a broken wire occurs inside the conductor, it can further enhance the restriction effect on the broken single wire.

[0043] Example 3

[0044] In this embodiment, the conductor is a type 6 ultra-flexible aluminum alloy conductor. Since type 6 conductors contain more fine-diameter monofilaments, their flexibility is further improved. At the same time, the risk of breakage increases with the increase in the number of monofilaments. Therefore, a polytetrafluoroethylene tape with a thickness of 0.05 to 0.12 mm is used to form a wrapping constraint layer. By improving the strength of the wrapping layer, the constraint ability on broken monofilaments is further improved, thus making it suitable for high-voltage main circuit harnesses of new energy vehicles and power battery connection harnesses.

[0045] In this embodiment, the polytetrafluoroethylene wrapping layer is not used only as an insulating layer, but rather to construct a persistent radial compression constraint structure around the conductor.

[0046] Specifically, the PTFE tape is spirally wrapped around the conductor assembly. The wrapping tension is controlled to create a pre-tight state around the conductor. After wrapping, the PTFE tape applies a continuous inward radial compressive force to the conductor assembly, keeping the conductor bundle in a stable and concentrated state. Then, it enters the silicone rubber extrusion and high-temperature vulcanization process. Because PTFE has excellent high-temperature resistance, it will not undergo significant melting, carbonization, thermal shrinkage, or mechanical strength failure during high-temperature vulcanization. Therefore, it can continuously maintain the radial constraint on the conductor bundle. When the conductor is bent, coiled, transported, or vibrated, some aluminum filaments may break locally. In the traditional structure, the broken aluminum wire tip tends to flip outward under the residual stress release and gradually move towards the insulation layer. Because silicone rubber has soft properties, when the sharp broken wire continues to act on the insulation layer, it is easy to form a local puncture, which leads to insulation failure.

[0047] In this embodiment, the radial compression constraint structure formed by the polytetrafluoroethylene wrapping layer can continuously cover the conductor bundle. When a single filament breaks, the tip of the broken filament is radially restricted by the polytetrafluoroethylene wrapping layer, and its movement trajectory is constrained within the inner region of the conductor bundle. The broken wire tip is restricted by the radial constraint structure formed by the polytetrafluoroethylene wrapping layer, and its radial displacement is suppressed, thereby reducing the possibility of the broken wire extending towards the insulation layer. Therefore, the broken wire tip is difficult to break through the constraint boundary formed by the wrapping layer, and the broken wire is ultimately kept inside the conductor bundle. This achieves the following: the broken wire is kept inside the conductor bundle; direct contact between the broken wire and the silicone rubber insulation layer is blocked; the broken wire is prevented from piercing the insulation layer; the risk of insulation breakdown is reduced; and the long-term reliability of high-voltage cables is improved.

[0048] By setting a radial compression constraint structure formed by the polytetrafluoroethylene wrapping layer, the probability of broken wires turning outward can be reduced, and the risk of broken wires piercing the insulation layer can be reduced.

[0049] During the research and development process, the applicant discovered that the key factor causing insulation failure is not the number of broken wires themselves, but rather the radial migration behavior of the broken wires after they form. To address this issue, this application incorporates a polytetrafluoroethylene (PTFE) wrapping layer around the conductor and utilizes the wrapping tension to create a persistent radial compression constraint structure. When a broken wire occurs inside the conductor, this radial compression constraint structure restricts the outward migration of the broken wire, keeping it within the conductor bundle and thus reducing the risk of the broken wire piercing the silicone rubber insulation layer.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0051] The above description is only used to illustrate the technical solutions of the present invention, and is not intended to limit them. Although the present invention has been described in detail with reference to the foregoing, those skilled in the art should understand that modifications can still be made to the foregoing technical solutions, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for automotive applications, characterized in that: include: The conductor is a flexible aluminum alloy conductor formed by twisting together multiple aluminum alloy monofilaments. A wrapping constraint layer is disposed on the outer periphery of the conductor; A silicone rubber insulating layer is wrapped around the outside of the wrapping constraint layer; in, A wrapping constraint layer is wrapped around the outer periphery of the conductor to form a continuous circumferential constraint structure, which applies radial compressive constraint to the conductor. When a single filament inside the conductor breaks, the circumferential constraint structure is used to restrict the broken filament from migrating to the outer periphery of the conductor bundle, keeping the broken filament inside the conductor bundle and thus reducing the risk of the broken filament piercing the silicone rubber insulation layer. The wrapping constraint layer is formed by wrapping with polytetrafluoroethylene tape; The polytetrafluoroethylene tape is wrapped around the conductor in a spiral manner, with an overlap rate of 30% to 70%. The continuous vulcanization temperature is 300℃~850℃, and the wrapping constraint layer maintains a radial constraint effect on the conductor during the vulcanization process.

2. The high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for in-vehicle use according to claim 1, characterized in that: The conductor is a Class 5 flexible aluminum alloy conductor or a Class 6 flexible aluminum alloy conductor.

3. The high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for in-vehicle use according to claim 1, characterized in that: The thickness of the polytetrafluoroethylene tape is 0.03 to 0.12 mm.

4. The high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for in-vehicle use according to claim 1, characterized in that: The polytetrafluoroethylene tape uses a double-layer reverse wrapping structure to form a wrapping constraint layer.

5. The high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for in-vehicle use according to claim 1, characterized in that: The silicone rubber insulation layer is formed by cold-feed extrusion and then cross-linked and cured by continuous high-temperature vulcanization.

6. A method for preparing a high-current-carrying, high-temperature-resistant, high-voltage aluminum wire for automotive applications according to claim 1, characterized in that, Includes the following steps: S1. Provide flexible aluminum alloy conductors; S2. A wrapping constraint layer is formed around the outer periphery of the conductor, and the wrapping constraint layer forms a continuous circumferential constraint structure. S3. Extrude a silicone rubber insulating layer on the outside of the wrapping constraint layer; S4. The extruded cable is fed into a high-temperature vulcanizing device for continuous vulcanization. in, The wrapping constraint layer maintains a continuous radial compressive constraint on the conductor during the vulcanization process to limit the outward migration of broken monofilaments inside the conductor.

7. The preparation method according to claim 6, characterized in that: In step S2, polytetrafluoroethylene (PTFE) tape is used for wrapping, and the wrapping tension is used to make the PTFE tape form a pre-tight state on the outer periphery of the conductor in order to construct a continuous radial compression constraint structure.

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