DKLW48100-WALL 48V100AH lithium battery Lifepo4

BMS is mainly used to improve the utilization rate of the battery, prevent the battery from overcharging and over discharging, extend the service life of the battery, and monitor the status of the battery. Generally speaking, it is a system for managing, controlling and using battery packs.

The three core functions of BMS are cell monitoring, state of charge (SOC) estimation and cell equalization.

1. Cell monitoring. The main function of cell monitoring technology is to collect the voltage of single battery; Single battery temperature collection; Battery pack current detection. The accurate measurement of temperature is also very important for the working state of the battery pack, including the temperature measurement of a single battery and the temperature monitoring of the cooling liquid of the battery pack. This requires a reasonable setting of the position and number of temperature sensors to form a good cooperation with the BMS control module. The monitoring of the temperature of the cooling liquid of the battery pack focuses on the temperature of the fluid at the inlet and outlet, and the selection of the monitoring accuracy is similar to that of the single battery.

2. SOC technology Single cell SOC calculation is the key and difficult point in BMS. SOC is the most important parameter in BMS. Because everything else is based on SOC, its accuracy and robustness (also called error correction capability) are extremely important. Without an accurate SOC, no amount of protection functions can make the BMS work normally, because the battery will often be in a protected state, and the battery life cannot be extended. The higher the accuracy of SOC estimation, the higher the range of electric vehicles for batteries with the same capacity. High precision SOC estimation can maximize the efficiency of the battery pack. At present, the most commonly used calculation methods are ampere hour integration method and open circuit voltage calibration method. By establishing a battery model and collecting a large amount of data, the actual data is compared with the calculated data. This is also a technical secret of each company, which requires a long time and a large amount of data accumulation. It is also the part with the highest technical content of lithium batteries.

3. Passive equalization technology generally uses resistance heat release to release the excess power of high-capacity batteries, so as to achieve the purpose of equalization. The circuit is simple and reliable, with low cost, but the battery efficiency is also low. Transferring excess power to high-capacity cells during active equalizing charging and to low capacity cells during discharging can improve the use efficiency, but the cost is higher, the circuit is complex and the reliability is low. In the future, with the improvement of the consistency of the cell, the demand for passive equalization may decrease.