Battery, motor, and electronic control technologies are the three core technologies of electric vehicles, among which the most critical function within the electronic control system is the BMS (Battery Management System). As a key pillar behind intelligent driving, the BMS ensures the safe operation of the power battery in electric vehicles.
The BMS is a system that monitors and manages the battery. By collecting and calculating parameters such as voltage, current, temperature, and SOC (State of Charge), it controls the battery's charging and discharging processes. This enables battery protection, enhances overall performance, and serves as a vital link between the onboard power battery and the electric vehicle.
The hardware architecture of a BMS includes the following four parts:
1.Main Board:
Collects sampling data from slave boards, communicates with the vehicle via low-voltage electrical interfaces, and controls the relays within the BDU. It monitors various battery conditions to ensure safe operation during charging and discharging.
2.Slave Board:
Monitors individual cell voltage, temperature, and other parameters within the module, and transmits this information to the main board. It also supports battery balancing. Communication between the slave board and main board is typically via CAN bus or daisy-chain communication (a topology that connects nodes from a central point outward like a chain).
3.BDU (Battery Disconnect Unit):
Connects to the vehicle's high-voltage load and fast-charging harness through high-voltage interfaces. It includes components such as the pre-charge circuit, main positive relay, main negative relay, and fast-charge relay, all controlled by the main board.
4.High-Voltage Control Board:
This can be integrated into the main board or exist as a separate unit. It monitors the battery pack's voltage and current in real time and includes functions such as pre-charge detection and insulation monitoring.
The main chips used in a Battery Management System (BMS) include Analog Front-End (AFE), Microcontroller Unit (MCU), Analog ADC (Analog Converter), and Digital Isolator. The AFE (Analog Front-End) chip (specifically referring to the battery sampling chip in a BMS) is used to collect information such as cell voltage and temperature, and also supports battery balancing; typically, this chip integrates passive balancing functionality. The MCU chip in the BMS processes the information collected by the AFE chip and calculates the State of Charge (SOC). SOC is a crucial parameter in the battery management system; all other parameters are calculated based on SOC. Therefore, the battery management system places high performance requirements on the MCU chip.
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