SoC estimation of LFP Battery Based on EKF Observer and a Full Polynomial Parameters-Model

Abstract

Thanks to their interesting characteristics in terms of energetic performances and safety, Li-ion batteries Lithium Ferro-Phosphate (LFP) type are increasingly embedded in Electric Vehicles (EV). Hence a great interest to guarantee a high autonomy of the vehicle respecting the specific behavior of LFP batteries with accurate state of charge (SoC) monitoring. In this paper, we propose a full polynomial parameters-model of the battery first order model. The proposed model combined with the Extended Kalman Filter (EKF) is then used to estimate accurately the SoC of LFP battery. This monitoring method has been validated for Dynamic Discharge Pulse (DDP) profile, thus a high accuracy of SoC estimation is recorded, in fact an average error about 0.05% of SoC is obtained.