Performance of lithium ion batteries whose electrodes are composed of particles of different sizes is studied. Simplified model developed in (Henquin and Aguirre, AIChE J. 2015; 61:90-102) is extended and the simulations are compared with experiments from the literature so as to validate this new model. The differences in current density observed in particles of different sizes, which are in contact, depend on particle size and state of charge. Internal particle to particle discharge currents are observed during relaxation times. A parametric study of the applied current and particle sizes of electrodes is performed to evaluate cell performance, with emphasis on cell voltage and final capacity measurement. The evolution of reaction rates on the surface of electrode particles and their corresponding states of charge are depicted. An analysis of relaxation times in terms of cell voltage, current density, equilibrium potentials, and overpotentials is included. (C) 2017 American Institute of Chemical Engineers