Developing an Advanced Equivalent Circuit Model for a Li-ion Battery for Battery Monitoring in Electric Vehicles

In the improved second-order equivalent circuit model (ECM) presented in this paper, the battery responses to operational (voltage and current) and non-operational (ambient temperature) parameters were taken into account to reach high accuracy to improve the estimation of state of charge (SOC) and state of health (SOH) of lithium–ion batteries (LIBs) of electric vehicles (EVs). Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. The performance of the model is verified by comparing the experimental and simulated voltage under hybrid pulse power characterization (HPPC) test profile.