Accurate Equivalent Circuit Parameter Estimation Using Electrochemical Battery Modelling for Pulsed Load Applications

There has been a growing need to electrify almost every transportation sector to curtail global warming. Energy dense Lithium-ion based energy storage systems power most of the Electric Vehicles (EVs) in this decade. Present Equivalent circuit models of such batteries use lumped model parameters for calculation purposes. Though this approximation is sufficient to model constant current charge characteristics, transient dynamics are not captured by employing such approximate models. In this paper equivalent battery circuit parameters are derived from the Doyle-Fuller-Newman Model (DFN), an electrochemistry-based battery model. This detailed model is particularly useful to accurately capture transient load behaviour. The proposed approach is used to derive circuit parameters for two RC pair battery equivalent circuit. A LGM50 battery was discharged at regular intervals at 1 C rate to validate the proposed technique.