Estimating the Equivalent Circuit of Lithium-Ion Batteries During Operation

Abstract

This paper deals with the issue of estimating the equivalent circuit of lithium-ion cells during normal operation. The study explores fundamental battery models, such as the simplified Randles circuit and the full Randles circuit. Conventional methods for model estimation, including Electrochemical Impedance Spectroscopy (EIS) and Galvanostatic Intermittent Titration Technique (GITT) are examined. The research extends into the real-world data analysis, gained from a home photovoltaic system. Using these data, an algorithm to estimate the equivalent circuit model during battery operation is evaluated. The study investigates the correlation between the proposed algorithm's outcomes and results obtained through EIS and GITT methods.