Three core functions and five misunderstandings of lithium battery BMS

The three core functions of lithium battery BMS and five major mistakes The three core functions of BMS are cell monitoring, SOC budget and cell balance. The core function of BMS 1) Battery monitoring skills 1. Single battery voltage collection; 2. Single battery temperature collection; 3. Battery current detection; Accurate temperature measurement is also very important for the working status of the battery pack, including the temperature measurement of a single battery and Temperature monitoring of battery pack coolant. This requires reasonable setting of the location and use times of the temperature sensor, and good coordination with the BMS control module. The key to monitoring the temperature of the liquid in the battery pack is the temperature of the fluid inlet and outlet. 2) SOC (State of Charge) skills: In short, how much electricity is left in the battery SOC is the most important parameter in BMS. Since all other parameters are based on SOC, the accuracy and robustness of SOC (also Called error correction) is extremely important. If there is no accurate SOC, no amount of maintenance can make the BMS work normally, because the battery is often in a maintenance state and cannot extend the battery life. The higher the accuracy of the SOC budget, the greater the range of batteries with the same capacity. The high-precision SOC budget allows the battery pack to achieve maximum efficiency. 3) Balance skills Forced balance generally uses resistance heating to release more power from large-capacity batteries, so as to achieve the purpose of balance. The circuit is simple and reliable, and the cost is low, but the efficiency of the battery is also low. Active balance charging transfers excess power to large-capacity batteries, and discharging transfers excess power to small-capacity batteries, which can improve the efficiency of use, but the cost is high, the circuit is messy, and the reliability is low. In the future, as cell consistency improves, the need for forced balance may decrease. The more misunderstandings about Bristol-Myers Squibb, the better. The functions can meet the requirements, not the more the better, the simpler and firmer the system, the higher the possibility. 2) Deliberately seek the acquisition accuracy of parameters such as voltage and temperature. Due to the above reasons, the accuracy can meet the requirements. Too high accuracy does not necessarily bring about the improvement of BMS performance, on the contrary, it will increase the cost. 3) BMS can correct batteries with poor performance. BMS does not repair inferior batteries; in the best case, it can slow its deterioration and limit its impact. 4) Equalization can handle the inconsistency of battery capacity. A single charge-discharge balance has no obvious effect on the capacity difference, and only a large current discharge balance can improve the capacity inconsistency. 5) Blindly pursue the consistency of the charge and discharge cut-off voltage. Regarding a BMS with only charge balance or discharge balance, it does not make sense to blindly search for cut-off voltage consistency at the end. Only when there is a large charge-discharge balance, is it necessary to discuss the consistency of the closing-off voltage. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Material and structure of battery