A battery cell equalizer with continuous charging current for energy storage system

For battery-based energy storage systems, cell equalizer is essential to improve battery life cycle and maximize capacity utilization. However conventional cell equalizers require long durations to accomplish cell balancing due to power rating and output current limitation. For high power application such as in green building, renewable energy and electrical vehicles, fast equalizing is vital. In this paper, a current-fed full-bridge topology is proposed and is targeted for fast cell equalizing. Compared to conventional technology, the proposed topology can be applied in high power application to reduce equalizing time. Furthermore, the proposed topology requires fewer components. Cell equalizing algorithm based on automatically switched maximum current/voltage control is introduced to ensure all the battery cells work safely in equalizing process and minimize equalizing time. The proposed cell equalizer has been verified by simulation and experiment.