State of Charge Estimation of Lithium-Ion Battery Using Energy Consumption Analysis

摘要

The traditional electric current integral algorithm cannot accurately estimate a lithium-ion battery's state of charge (SOC) under complex discharge conditions. Therefore, in this study, a new estimation method based on a power integral algorithm is proposed. First, the first-order Thevenin equivalent circuit model is selected, and the energy storage and loss of the lithium-ion battery during charging and discharging operations are analyzed. Second, the inherent disadvantages of the electric current integral algorithm are analyzed, and an SOC estimation based on the power integral algorithm is presented. The error correction for the SOC estimation is derived using the extended Kalman filter (EKF). Using the established test bench, the effects of environmental temperature, state of health, and current density on the SOC estimation are analyzed. The experimental results show that the proposed method combining the power integral and EKF can accurately estimate the SOC of a lithium-ion battery.