The battery management system (BMS), also commonly known as the battery nanny or battery housekeeper, is a control system to protect the safety of the power battery. It monitors the battery's use status at all times to prevent the battery from overcharging and overdischarging, as well as short-circuit protection and prolonging the battery life. Service life, monitor the battery status, etc., through the equalization function, make the battery cells consistent, and provide guarantee for the safety of the battery pack.

The hardware architecture of the battery management system includes four aspects.

1. The main board, as the brain of the BMS, collects sampling information from each slave board (usually called LCU), communicates with the vehicle through a low-voltage electrical interface, controls the action of the relay in the BDU (high-voltage breaker box), and implements battery monitoring Various states to ensure the safe use of the battery during charging and discharging;

2. The slave board (LCU), as the sentinel of the BMS, monitors the cell voltage, cell temperature and other information of the module, and transmits the information to the main board. It has the function of battery balancing. The communication method between the slave board and the main board is usually CAN , CANBUS, RS485, SMBUS, UART, I2C.

3. BDU is the gate for battery pack power to enter and exit. It is connected to the vehicle's high-voltage load and fast-charging harness through the high-voltage electrical interface, including pre-charging circuit, total positive relay, total negative relay, fast charging relay, etc., controlled by the main board;

4. The high-voltage control board, the door guard for the battery pack's power in and out, can be integrated on the main board or independently, and it can monitor the voltage and current of the battery pack in real time. It also contains pre-charge detection and insulation detection functions.