SOC Estimation of Lithium-Ion Batteries Based on Parameter-Dependent State-Space Model

Abstract

This paper is concerned with the State-Of-Charge (SOC) estimation for lithium-ion batteries by using an equivalent circuit model and the extended Kalman filtering (EKF) technique. The physical parameters in the equivalent circuit are dependent on both the temperature and the SOC of the battery. We propose a new method for improving the estimation accuracy based on a parameter-dependent state-state space model. To be more specific, we derive a parameter-dependent state-space model by viewing these parameters as time-varying parameters，and then apply the extended Kalman filter to estimate the SOC. Experimental results demonstrate the effectiveness of the proposed method.