基于动态可重构电池储能系统的新型SOC一致性评估方法

Abstract The second-life use of retired electric vehicle (EV) batteries in energy storage systems (ESSs) plays a crucial role in resource recycling and environmental protection. However, the significant inconsistency among retired battery modules poses safety risks to the battery energy storage systems (BESSs). State of charge (SOC) consistency evaluation of traditional BESSs is challenging due to the complex working conditions and the relatively flat OCV-SOC (open circuit voltage-SOC) curve of LiFePO 4 modules. Therefore, we propose a novel SOC consistency evaluation method based on dynamic reconfigurable battery system (DRBS). First, fast online OCV estimation can be achieved by the DRBS due to its ability to disconnect modules from the system. Then, coefficient of variation (CV) of OCV is designated as the SOC consistency indicator (CI). A CV calculation method is proposed to overcome voltage plateau and polarization effect , which facilitates the computation of consistency scores. Finally, the proposed method is verified by a real case study on a dynamic reconfigurable battery energy storage station utilizing retired EV modules. The results indicate that the proposed method can quantitatively evaluate the consistency levels across different DRBSs and effectively identify those with significant inconsistency.