Research on a modular equalization topology for battery storage system

Several batteries are connected in series in the storage system. Because of the differences among the batteries, the voltages of some batteries can be too high/low in the charging/discharging processes, which may shorten the lifetime of the system and reduce the reliability. We proposed a modular equalization topology for the batteries in series, and analyzed the switching states and the equivalent circuits. Furthermore, we calculated the law of the energy delivered in every cycle, proposed a model, and proposed a control strategy. The simulation and experimental results can verify the proposed topology and strategy. The system works normally and can be expanded in a simple way. Also the control is easy. Thus the topology is practical.