Approach to development planning of high voltage cables for electric vehicles
China [CN] For most automobile enterprises or manufacturers, it is a realistic path to maintain the existing electric vehicles in the short term. The larger the cable current, the larger the cable cross-sectional area required to transmit power without overheating at the same voltage level. This challenge will affect: the high voltage of the charging socket in the vehicle, the cable from the charging socket to the battery pack, the fast charging contactor, the main positive, main and negative contactors, the main fuse, the module wiring block, the internal wiring block of the battery cell and other equipment operating conditions.
After professional production, the R & D team found that the important point is the continuous static current from 10s to 20min in the R & D. In the early production, it was found that because the current is fluctuating, although the peak point of the required power of the whole drive is relatively high, the duration will only last for 10s and then decrease. The total current can be achieved by using a root mean square (RMS) design. In the design of DC fast charging, the process of power dissipation is the heating of wires, cables and contact resistance, and it changes with the increase of temperature during operation.
Among them, in some life cycles, some areas with high impedance or limited heat dissipation may become the bottleneck of thermal management. If the heat cannot be sufficiently dissipated, the heating process will not be affected by the outside world. According to the current mainstream design, the current test mainly focuses on the design below 300A.
Considering the practical situation, the whole temperature connection point needs to be controlled below 100 degrees. The main reason is that more than one temperature will make the anti-corrosion coating of the conductor unstable. Similar to the temperature rise caused by the contact resistance and crimping resistance of the charging cable and connector below, the battery mentioned above will also appear inside. If it appears at the battery connection, it will have a great impact on the battery.
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