A Hierarchical Structure Approach of Battery Balancing Based on SOC

Due to the difference of lithium-ion cell will lead to over-charge or over-discharge, efficient battery balancing must be used in battery packs to keep it stable. Firstly, the State of Charge (SOC) that can better represent the battery capacity replaces the terminal voltage as a parameter for battery balancing. Then an enhanced battery model is proposal considering the hysteresis voltage of SOC. Next, the parameters of the model are obtained based on the data of the experimental test battery, and a more accurate SOC is estimated using extended Kalman filter (EKF). In view of the common battery balancing method, a practical active-passive hierarchical architecture with satisfying large current, moderate volume, and strong scalability is proposed. And in the end of the paper, use MATLAB/Simulink to verify the above method.