At present, the mainstream cooling methods mainly include air cooling and water cooling. The thermal management function of the BMS plays an important role in ensuring the safety of the power battery and prolonging its life. Online fault diagnosis and safety management, because high voltage electricity can cause great harm to the human body, so a very important function of BMS is online fault diagnosis and safety management. Common faults of battery systems include but are not limited to sensor faults, actuator faults, network faults, and various controller faults in various subsystems such as battery packs, high-voltage electrical circuits, and thermal management. The failure of the battery pack itself refers to overvoltage (overcharge), undervoltage (overdischarge), overcurrent, ultra-high temperature, internal short circuit failure, electrolyte leakage, insulation reduction, etc.