Implementation of State of Charge Estimation for Lithium-ion Battery Pack
combination algorithm; state of charge (SOC); open circuit voltage (OCV); extended Kalman filtering (EKF); ampere hour (Ah); battery management system (BMS)
State of charge (SOC) estimation is an increasingly important issue in battery management system (BMS). In addition to offering the real time display of battery parameters to user, the accurate SOC information would exert some controls over the charging and discharging process that in turn reduces the risk of cell over voltage. This paper proposes a method to conduct real-time monitoring of the battery state accurately, such as the battery charge and discharge current, voltage, temperature and the state of charge. SOC estimation error is made less than 5%.It can also timely alarm and carry out protection action in the abnormal state of the battery. A new method named combination algorithm is proposed in this paper in accordance with the characteristics of lithium-ion power battery.