Modeling of a Commercial Graphite/LiFePO4 Cell

An isothermal model for the electrochemical behavior of a commercial graphite/LiFePO 4 cell at 25 and 45°C is developed. Although it does not embed any special feature of the porous electrodes and of the two-phase process of the LiFePO 4 electrode, proper account of the experimental charge/discharge (from C/10 to 1C) and path-dependence effects of the commercial cell is achieved. The LiFePO 4 electrode is treated based on a resistive-reactant concept with multiple particles whereas a single-particle approach is used to model the graphite electrode. In order to refine the model parameters for each electrode, half cells are made either from the recovered LiFePO 4 or graphite electrodes vs. a Li counterelectrode. A detailed experiment/simulation analysis of half-cell and complete-cell data unfolds the impact of uniaxial pressure on the galvanostatic charge/discharge limitation and path dependence of the LiFePO 4 electrode in the coin cell and the commercial cell.