Abstract:The state of charge (SOC) of battery is one of the important parameters in battery management system (BMS). Accurate estimation of SOC is of great significance for production and operation. Firstly, the definition of SOC is explained. Secondly, the shortcomings of traditional single SOC estimation method are analyzed, and then, the research progress of SOC fusion estimation methods for battery in recent years, including neural network, Kalman filter and synthesis method, is discussed, and the advantages and disadvantages of each method are analyzed. Finally, the summary and prospect are given. It is proposed to make full use of data mining and deep learning technology and use the historical data recorded by BMS to estimate the SOC of battery, which is helpful to improve the calculation accuracy and application range.