In new energy vehicle battery packs, inconsistencies in manufacturing processes, material characteristics, and operating conditions lead to differences in capacity, internal resistance, and state of charge (SOC) among cells. As charging and discharging cycles continue, these inconsistencies further accumulate and amplify, resulting in a decline in available capacity, reduced energy utilization, and a shortened cycle life of the battery pack. Therefore, researching efficient and reliable battery balancing technologies is of great significance for improving the performance and operational safety of new energy vehicles power battery systems. To address the cell energy imbalance problem under complex operating conditions and during long-term operation, an active balancing method based on a bidirectional flyback converter is proposed. This method utilizes SOC as the balancing criterion to construct a target-oriented charging balancing control framework. Furthermore, an optimal energy transfer strategy considering both balancing efficiency and switching losses is designed to reduce the ineffective charging and discharging processes of high SOC cells, thereby achieving collaborative optimization between balancing speed and system energy consumption. In addition, switching actions are incorporated into the optimization process to improve energy transfer efficiency and reduce device losses. Simulation and experimental results demonstrate that the proposed method effectively accelerates the balancing process, suppresses ineffective discharge of high-SOC cells, and improves charging efficiency and consistency under different charging currents, initial SOC distributions, and target SOC conditions.