Comparative Study of EKF and SPKF for SOC Estimation of Lithium-ion Batteries

With the increasing prevalence of lithium-ion batteries, advancements are being made in battery management system (BMS) algorithms. One of the most critical parameters for battery safety and performance is the state of charge (SOC). Since directly measuring the remaining charge is not practical, various estimation methods are used. In this study, an equivalent circuit model was developed for the MOLICEL P45B cell used in the battery of an electric vehicle. Based on the developed model and experimental data, a comparison between the EKF and SPKF methods was conducted. According to the results, the SPKF method has better accuracy in SOC estimation than the EKF method.