Physically based modeling and simulation of a LiFePO4-based lithium-ion battery

Abstract

We present a detailed electrochemical model of a LiFePO4 battery based on a multi-scale continuum description of chemistry and transport [2]. Thermodynamic properties of active materials in form of enthalpy and entropy contribution are also included as electron transfer processes using Butler-Volmer type equations. Chemistry is coupled to mass, charge and heat transport taking place on multiple scales (atoms and electrons inside the solid active materials, ions in the liquid electrolyte, electrons in the current collectors, heat within the full cell). The model is parameterized and validated using experimental impedance data and discharge curves obtained by using commercial high-power cells (A123). The simulation agrees very well with the experiments obtained and allows a detailed insight into the electrochemical behavior of the cell as a function of operating conditions and state-of-charge. Discharge curves at different C-rates as well as simulated impedance measurements for different state-of-charges show the same behavior like experimental data. References [1] Padhi, A. K., Nanjundaswamy, K. S. and Goodenough, J. B. Phospho-olivines as positive-electrode materials for rechargeable lithium batteries, Journal of the Electrochemical Society vol.144 (1997), pp. 1188-1194 [2] Bessler, W. G., Gewies, S. and Vogler, M. A new framework for physically based modeling of solid oxide fuel cells, Electrochimica Acta vol. 53 (2007), p. 1782-1800.