Two different approaches were used to model the insertion of lithium ions into a carbon particle. In the first approach, a concentration gradient was considered as the driving force (DFM) for diffusion while in the second approach chemical potential driving force was used (CPM). Lithium ion-lithium ion interactions are included in the CPM model but not in the DFM model. These approaches were used to model a lithium foil/1 M LiClO4-propylene carbonate/carbon fiber cell. The model predictions indicate that the lithium ion-lithium ion interactions inside the particle play a significant role in predicting the electrochemical and thermal performance of the cell.