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The structural design scheme of the high-voltage line for electric vehicles

Date:2019/3/25 16:35:47

Countries around the world are vigorously developing new energy vehicles to reduce oil consumption and reduce carbon dioxide emissions. my country focuses on breakthroughs in batteries, electrodes and electronic control technologies to promote the development of pure electric vehicles and plug-in hybrid vehicles. With the development of the electric vehicle industry, the proportion of electric vehicle ownership in the total car ownership is getting higher and higher. Its supporting components will occupy a large market space, and there are higher requirements for the quality of components.

The following is the structural design of high-voltage cable for electric vehicles:

1. Conductor Design

The flexibility of high-voltage cables is mostly determined by the design of the conductor. This is why high-voltage cables use special conductors with a large number of very small diameter monofilaments. A certain number of monofilaments are bundled and then concentrically twisted to form the soft conductor required for high-voltage cables.

Another advantage of having more roots is better resistance to bending. The shortened pitch of the stranded wire can also improve the bending life of the high-voltage cable.

2. Insulation material

The choice of insulation material is mainly considering the heat resistance requirements and mechanical strength. Compared with standard battery cables, relatively soft materials can be reasonably selected to keep the specially designed stranded conductors flexible.

3. Cable formation

When the cable has multiple cores, it is usually necessary to twist the cores. In order to compensate for the distortion caused by the twisted high-voltage cable core, special equipment called back-twisting is required. In this process, the pay-off reel equipped with the dedicated twisting machine rotates in the opposite direction relative to the twisting direction. This is necessary to prevent the deformation tension of the cable.

According to the structure of the cable, padding is usually used to ensure a higher concentricity of the shielded cable, and a satisfactory high-voltage cable is finally obtained. The use of wrapping tape in the stranded cable core can maintain the flexibility of the cable.

4. Shield

Due to EMC (Electromagnetic Compatibility) requirements, multiple copper wires are used to form a braided shield. Tinned copper wire can make it more resistant to environmental influences such as oxidation. Using thin copper wire can maintain the design flexibility

The shielding needs to have a coverage of more than 90% to overcome the problem of high-frequency radiation generated by the switching power supply in the system and induced to the surrounding components through the cable.

For different needs of shielding effect, braided shielding can be combined with various other shielding, such as aluminum-plastic conforming film. A non-woven fabric can be wrapped around the shield to ensure that the sheath is easily peeled off during assembly.

5. Sheath

Like the insulation of the wire core, the sheath material is selected according to thermal and mechanical requirements. Due to direct contact, environmental properties such as resistance to liquids and abrasion are particularly important for the jacket. These characteristics mainly depend on the type of jacket material selected, and to some extent are also affected by the design of the jacket structure.

If special requirements, such as overcoming wear in the environment of the installation vehicle, require increased wear resistance, this needs to be considered when selecting materials. Test equipment is often used to simulate real-world conditions to verify these characteristics.

Choosing softer materials will benefit from flexibility, which may result in lower wear resistance of high-voltage cables.

According to the stipulations in the relevant specifications, the extruded jacket should be a bright orange, and special warning high-pressure marks can also be added according to the regulations.

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