BMS battery management system (English full name: battery management system), the main function of BMS is to maintain and manage battery cells, provide protections for batteries such as overcharge, overdischarge, and overcurrent, extend battery life, and enhance battery stability after grouping It can monitor battery status, collect and store information in real time, and process information during battery operation, exchange information with external devices, and solve the key issues of safety, ease of use and service life of the lithium battery system. In layman's terms, BMS It is a battery pack control management system.
Three core functions of BMS:
Lithium batteries will have temperature, voltage, current and other changes during operation. BMS can more accurately reflect the current working status of the battery pack by collecting data from the single battery, and form a good cooperation with the BMS control module. It is essential to ensure the stable operation of the batteries after they are assembled.
SOC technology is a difficult point in the BMS battery management system. The accuracy of SOC detection is an important indicator reflecting the reliability of the BMS. Why do you say that? Because everything in the battery pack is based on the SOC, the accuracy and error correction capability of the BMS on the SOC is extremely important.
The inaccuracy of the SOC may cause the battery pack to fail to work normally and remain in a protected state for a long time, and the high-precision SOC can maximize the efficiency of the battery.
In the battery management system of Tesla electric vehicles, SOC collection and error correction is the most technical part of the entire system. The current methods used include ampere-hour integration and open circuit voltage calibration. Through the establishment of a battery model and a large amount of data collection, the comparison with actual data calculation is a relatively reliable technical theory at present.
Balance is divided into active balance and passive balance. In a group of batteries, there will still be more or less data differences between single cells. This is also an important reason why the battery life shrinks after grouping. The balancing technology can reduce the battery life. The problem of the change of the parameters of the single battery in the overcharge of the battery pack, with the improvement of the consistency of the single battery and the improvement of the battery pack balancing technology, can greatly improve the service life of the battery after the battery pack.