Sensor Fusion-based Cell-to-Cell Inhomogeneity Reflection for Accurate SOC Estimation of The Serial/Parallel Battery Pack

Abstract

This paper proposes the novel battery pack modeling considering the voltage imbalance for estimating the state of charge (SOC). The characteristics of the cell in the battery pack are different in resistance and capacity due to the manufacturing process and temperature unbalance. Because of these effects, the deviation of the cell-to-cell’s voltage and capacity is intensified as the charging/discharging is repeated. In the proposed method, the sensor fusion method is used to update the characteristics of cell in battery pack and overcome the inaccurate measurement values of sensor. Since the battery management system (BMS) usually measures the voltage of the cell in battery pack, the proposed algorithm is constructed by using measurement fusion which fuses the sensing value (voltage).