State of Charge Estimation Based on a Composite Method for Power Lithium Battery

摘要

The state of change (SOC) is used to describe the remaining capacity of battery and its accuracy is very important for power battery. In this paper, according to the composite method, the dynamic system model is established, combining with the ampere hour integral method revised by the compensating factor and the equivalent circuit model. After that, the system state equation and observation equation is introduced. At the same time, the Kalman filtering achieves the minimum error of SOC estimation value. The SIMULINK tool is used to establish the mathematical model of dynamic system. The simulation results show that the composite method can monitor the battery SOC in real-time. Its accuracy can keep the error within 4 %, which is good practical value in the estimate of power battery SOC under the complex operating condition.