Comparison of Equivalent Circuit Model Parameterization Using GITT and EIS

Accurate parameterization of Equivalent Circuit Models (ECMs) is essential for reliable state estimation and dynamic simulation of lithium-ion (Li-ion) batteries. These models provide a representation of the electrochemical processes governing cell behavior and are widely applied across various fields, including electric mobility, stationary energy storage, avionics and industrial applications. This work investigates two commonly employed approaches for ECM parameter identification: Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS). Both methods were applied to Li-ion cells under controlled laboratory conditions and the parameters of a 3RC model were extracted and analyzed. The study compares time-domain and frequency-domain parameterization, addressing their methodological differences, measurement requirements and resulting model characteristics. To demonstrate practical applicability, the identified models were validated using real racing data from the TU Brno Racing Formula Student electric vehicle.