Parameter optimization of an electrochemical and thermal model for a lithium-ion commercial battery

Abstract

• Electrochemical P2D and 2D axi symmetric model of a LiFePO 4 /C battery. • Parametrization using a fast optimization algorithm. • Validation of the model with experimental data. In this work, a LiFePO 4 /C commercial cylindrical battery cell is modeled with a P2D model coupled with a 2D axisymmetric heat transfer model to adequately represent the electrochemical and thermal responses of a battery. Charge and discharge tests at different C-rates with a controlled environment temperature are used to validate the parameters selected for the model. Some relevant parameters were obtained from literature and by opening the battery and testing the electrodes with charge and discharge protocols and SEM images. The parameters for which no direct measurement can be done and have no consensus in literature, were obtained through an optimization process using the BOBYQA optimization algorithm, which allows a substantial reduction in calculation time compared to other methods. Model simulations and experimental battery measures show good agreement with maximum RMSE of 62 mV and 0.68 ∘ C, and mean relative errors of 1.76% and 2.36% for the voltage and temperature profiles in different discharge cycles.