Operating Performance Evaluation and Improvement Method of Reconfigurable Battery Energy Storage System

Battery energy storage system (BESS) has the advantages of highly flexible production and installation, good cycle life, and fast power response. It is widely used in power system. In BESS, a large number of single cells are connected in series or parallel. The traditional topology of BESS is the fixed series-parallel connection which means that the failure of any single cell may cause system-level failures. Besides the increase of battery difference will seriously affect the service life and efficiency of the BESS. Therefore, in this paper, the operating reliability evaluation and improvement theory is applied to the battery energy storage system. We analyze the working state and failure mechanism of the system components concerning with the real-time operating mode and the external working environment changes. The operating strategy is proposed based on the reconfigurable battery network, in order to avoid the weak link battery from participating in charging and discharging. The model and strategy are demonstrated in case studies based on the reconfigurable BESS. The operating life of battery system is extended to 3612 days, and the reliability is 96.18%. Test results of the BESS show the superiority and effects of this method.