Analysis of Extended Kalman Filter for SOC Estimation in Lithium-ion Batteries

Battery management system is essential for most electric vehicles (EVs) to ensure the safe operation of the vehicle. State of charge (SOC) estimation plays a vital role in checking and controlling the status of the battery so as to ensure that battery is operating within safe limits. In this paper, different methods of the state of charge estimation have been implemented and based on conclusions drawn extended Kalman filter (EKF) is considered to be the most promising technique to estimate the SOC of a battery under different conditions. EKF is a non-linear observer which is used to remove process and sensor noise, any prior knowledge of initial SOC is redundant. In addition, the robustness of EKF is shown using the chi-squared method. The proposed model is simulated in MATLAB/Simulink software with precise estimated parameters.