Parametrization of equivalent circuit models for lithium-ion batteries using galvanostatic intermittent titration technique

This study presents an experimental methodology for parameterizing an Equivalent Circuit Model (ECM) of lithium-ion (Li-ion) batteries using the Galvanostatic Intermittent Titration Technique (GITT). ECMs are widely used for battery modeling due to their ability to approximate battery behavior with relatively low computational complexity. However, their accuracy strongly depends on precise identification of internal resistances and time constants, which define transient responses related to charge transfer and diffusion processes. In this work, a 3RC ECM configuration is employed to capture both fast and slow relaxation effects, enabling a more detailed characterization of the battery’s dynamic behavior. The experimental procedure consists of applying controlled current pulses followed by relaxation periods, during which voltage recovery is analyzed to extract key parameters. To refine the extracted values and ensure an optimal match between the model and measured voltage response, an iterative optimization process is applied, minimizing the discrepancy between simulated and experimental data. The proposed approach significantly enhances the accuracy of ECM parameterization, leading to a more reliable representation of lithium-ion battery dynamics across different States-of-Charge (SOC). The findings of this study contribute to improved state estimation, enhanced predictive maintenance, and more effective battery management strategies, ultimately supporting the optimization of energy storage systems and advancing battery performance modeling.