When the car is parked at rest, the high-voltage safety management system needs to conduct an insulation measurement on the high-voltage grid system every certain time (20 s or 30 s), that is, to determine whether there is an insulation fault in the high-voltage grid system. The entire high-voltage loop system includes the inside of the power battery, Power line, electric drive system (motor controller and motor three-phase line) and wires connected to accessories of high-voltage equipment. When an insulation fault is detected and the fault persists, the instrument will display an insulation fault indication to remind the driver.
Generally, electric vehicles use a large-capacity power battery of about 400 V as the power source to drive the car, so the power battery that is not cut off will cause threats and injuries to cars and people that cannot be ignored. If the car collides, rolls over, or is hit by other cars in the charging state and other accidents, it will cause friction or contact between the power battery pack, high-voltage electrical equipment and high-voltage wiring harness, etc., and the body, causing potential damage. Hazards such as insulation failure and short circuit.