Modeling of a Commercial Graphite/LiFePO4 Cell

An isothermal model for the electrochemical behavior of a commercial graphite/LiFePO4 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 LiFePO4 electrode, proper account of the experimental charge/discharge (from C/10 to 1C) and path-dependence effects of the commercial cell is achieved. The LiFePO4 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 LiFePO4 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 LiFePO4 electrode in the coin cell and the commercial cell.