Compared with traditional fuel vehicles, the fault categories of electric vehicles have been added due to the existence of power battery packs, which can be summarized as insulation resistance faults, overvoltage and undervoltage faults, current faults, contact point status faults, high voltage interlock faults and Charge interlock failure, etc.
In order to facilitate the control and management of the operation of the whole vehicle, the battery faults are managed by levels.
The faults of electric vehicle power batteries are usually divided into two levels, level I fault (alarm fault) and level II fault (serious fault).
When the battery management system BMS detects a level I alarm fault, the vehicle controller will adjust the control parameters to reduce the battery output current and power.
When the battery management system BMS detects a level II serious fault, it will send a request to cut off the high-voltage power to the vehicle controller through the communication line. In the control strategy, the battery management system can forcibly cut off a group of relays to ensure the safety of the vehicle and the occupants.