In this paper, a novel active battery equalization system is proposed for the operation of battery packs in electric vehicles. The system employs a bidirectional DC-DC flyback converter and an equalization algorithm based on Extended Kalman Filter (EKF) prediction SOC to achieve active equalization between cells by optimizing the control strategy, aiming to improve the lifetime and safety of the battery pack in the application, and thus the energy utilization and stability of the system. Simulations and experimental results are presented.