A novel state of charge estimation method for ternary lithium batteries based on system function and extended kalman filter

Abstract

The Equivalent Thevenin model is establish to describe the external performance of ternary lithium ion battery base on Hybrid Pulse Power Characteristic experiment by identifying and verifying model parameters. The state of charge estimation model is built in SIMULINK using Extended Kalman Filter algorithm and system function of MATLAB. The Simulation results under the working conditions of the experimental data shows that, the maximum error of the Thevenin model is 0.08V and its average error is 0.04V. Based on the Thevenin model, the state of charge estimation result shows a better performance in accuracy and robustness compare with traditional coulomb counting method. The maximum error is less than 0.01 and the average error is 0.008 which shows the systematic process and the correctness of the estimation method in this paper.