Estimation of Equivalent Circuit Model Parameters for a Generic Battery Using Least-Square Method

A generic battery represents a generalized battery model. This battery does not use the parameters of the battery, and only works with the maximum charging point, breakpoint, and nominal point. In this paper, two widely used electrical equivalent circuit models (ECMs), i.e., 1-RC and 2-RC are constructed to represent the generic battery model to analyze battery characteristics easily. So, ECM can be used as a generalized battery model, and it is the widely used modeling technique for State-of-Charge (SOC), State-of-Health (SOH) estimation, etc. of the battery. ECM and generic battery models are charged/discharged using the same current profile. The parameters of the ECM are estimated using the simulated current and voltage profile of the generic battery by the least-square method. This paper shows a detailed calculation for the ECM parameters estimation, and ECM can replace the generic battery. The comparison of estimated SOC with generic battery SOC for the same testing condition has been done to validate the modeling of the battery. Furthermore, A lithium-iron-phosphate (LFP) battery voltage profile is compared with ECM and generic battery voltage profile to validate the estimated parameters of the ECM.