There are many kinds of high-voltage wires for new energy vehicles, such as 3 mm? 2, 4 mm? 2, 16 mm? 2, 25 mm? 2, 35 mm? 2, 50 mm? Or even 70 mm? 2. Taking a pure electric vehicle as an example, under the high voltage of nearly 400V, the high-voltage wire used by 85KW motor is obviously different from that used by 6.6kw charger - "thickness" refers to the difference in cross-sectional area of copper wire, which is also obvious. Therefore, two kinds of high-voltage wire harness are necessary for new energy vehicle high-voltage wires, which are assembled on different parts according to power demand.
Is there any special design for high voltage line of new energy vehicle?
Careful friends can also find that the cable structure of high-voltage wire harness and household cable is somewhat different.
(1) The household cable is a solid copper core, while the high voltage cable is composed of several thin copper wires.
Increase conductivity. When there is alternating current or alternating magnetic field in the conductor, the "skin effect" will be produced. The current will be concentrated in the "skin part" of the conductor, and the current density on the surface of the conductor is greater than that of the center. In short, it can be understood that the surface is mainly conductive. The higher the frequency of alternating current, the more obvious the skin effect. The household electricity is 220 V, 50 Hz. The high-voltage platform of new energy vehicles is 300-400v, and the frequency can reach kHz level, which is dozens of times that of household appliances. Therefore, the area of "core" part of high-voltage wiring harness must be reduced. To take an extreme example, if the wire is infinitely thin, it can be seen that the entire conductor is conducting, and the conductivity of the high-voltage harness composed of these countless thin wires can be significantly enhanced.
(2) High voltage wire harness of new energy vehicle has shielding layer
Maxwell said electricity makes magnetism. When an electric current passes through the wire, a magnetic field will be generated around it. The shielding layer can shield the electromagnetic field in the wire bundle without affecting other components and reducing electromagnetic radiation. It can also shield the external influence and prevent the interference of external magnetic field.
Therefore, the basic principle of household electricity and vehicle wiring harness is the same. The appropriate wire is selected according to the current and voltage requirements, and the thicker the wire is, the better. Moreover, due to the more stringent use conditions, the vehicle high-voltage wiring harness has higher standard requirements, and more details will be considered in the design, which is safer and more durable.
