Circulation Suppression Strategy for Reconfigurable Battery Packs Based on Crisscross Optimization

The significant differences of characteristics among the retired batteries reduce the effective capacity and safety of energy storage system, which severely prevent the reusing of retired batteries. The reconfigurable battery pack, which can flexibly switch the connections among batteries, is an effective solution to cope with the differences of their characteristics. However, the circulating currents in the battery pack, which are caused by the voltage differences among the batteries, will reduce the energy efficiency and the batteries' life-cycle, even cause safety problems such as local overheating. In this paper, an optimization strategy for the path combination of the reconfigurable battery pack is proposed to maximize the paralleled branches and suppress the circulating currents. An optimization model is established, based on which a round binary crisscross optimization algorithm is designed. Hence, overcoming the non-deterministic polynomia hard problem in the path combination optimization of the reconfigurable battery pack. Finally, the simulation and experiment results verify that the proposed path combination optimization strategy is able to effectively suppress circulating currents.