Battery Management System (BMS) is a system that manages batteries, usually with the function of measuring battery voltage to prevent or avoid abnormal conditions such as battery discharge, overcharging, and overheating. With the development of technology, many functions have gradually been added.

The battery management system is closely integrated with the power battery of electric vehicles, which detects the voltage, current, and temperature of the battery in real-time through sensors. At the same time, it also performs leakage detection, thermal management, battery balance management, alarm reminder, calculates the remaining capacity (SOC) and discharge power, reports the degree of battery degradation (SOH) and remaining capacity (SOC) status, According to the voltage, current, and temperature of the battery, algorithms are used to control the maximum output power to obtain the maximum driving range, and algorithms are used to control the charger for optimal current charging. Real time communication is carried out with the vehicle main controller, motor controller, energy control system, vehicle display system, etc. through CAN bus interface.

1. Battery protection, similar to PCM, includes over charging, over discharging, over temperature, over current, and short circuit protection. Like ordinary lithium manganese batteries and ternary lithium batteries, once any battery voltage exceeds 4.2V or any battery voltage is below 3.0V, the system will automatically cut off the charging or discharging circuit. If the battery temperature exceeds the working temperature of the battery or the current exceeds the discharge current of the battery, the system will automatically cut off the current path to ensure the safety of the battery and system.

2. Energy balance: The entire battery pack, due to the series connection of many batteries, after a certain period of operation, will exhibit significant differences due to the inconsistency of its battery cells and operating temperature, which has a significant impact on the battery life and system usage. Energy balance is to compensate for the differences between individual battery cells and perform some active or passive charging or discharging management, Ensure battery consistency and extend battery life.

From the generation to the end of its lifespan, there are safety issues with power lithium batteries. Even if they fully comply with international safety standards when leaving the factory, they will evolve from a safe state to an unsafe state during use. The performance of high-quality individual batteries will gradually decline and reach the limit of their lifespan. Poor quality individual batteries will gradually experience various abnormal deterioration and decline in their performance during use, entering the unsafe state of concern. This is a gradual and cumulative process of change.

The lithium battery BMS management system is not as dispensable as some battery production companies say, but rather a must have, and it also runs throughout the application of battery packs. There have been many studies on lithium battery management systems both domestically and internationally, and they have started to be applied in many fields, which can meet the needs of some markets. The application of lithium power batteries has put forward higher requirements for battery management systems, ensuring the safety of power battery packs is the primary task of lithium power battery management systems.