This is for safety reasons, because there is high voltage on the new energy vehicle. In order to accidentally encounter high voltage, the power supply must be cut off before maintenance. Generally, high-voltage maintenance is carried out during power failure, such as the detection of power battery, the maintenance of motor and the maintenance of vehicle charger.

Considering the safety of power control and driving of new energy vehicles, it is necessary to cut off power at high voltage before operation. When working on electrical equipment with complete or partial power failure of new energy vehicles, the following measures must be completed: (1) power failure; (2) padlock; (3) check the power; (4) discharging; (5) hanging signs; (6) installing barriers; (7) Having a guardian. (seven steps), I hope it will help you.