Capacity loss reduction using smart-battery management system for Li-ion battery energy storage systems

Compared to conventional empirical or equivalent circuit-based Battery Management Systems (BMS), Advanced Battery Management Systems (ABMS) incorporate sophisticated electrochemical battery models that estimate health-related states with improved accuracy to achieve the desired outcomes. Equivalent Circuit Models based on electrochemical principles are used to reduce the complexity of the sophisticated electrochemical battery models while ensuring the required accuracy. Side reaction induced battery capacity loss is one of the crucial aspects to be addressed in ABMS. This paper proposes a control strategy to minimize the side reaction induced capacity loss by changing the cell series-parallel configuration dynamically inside the battery pack. Reduced-order equivalent circuit model based on electrochemical theory is adopted to model the internal kinetics of Li-ion battery. The cells which have a better State of Health (SOH) condition given the higher priority to contribute to the output voltage and connect in series than the cells with lower SOH. Simulation results show a considerable amount of capacity loss reduction after introducing the proposed method.