Feasibility Study of Modified Single-Particle Model for Composite Cathode at High-Rate Discharge

Abstract

In order to simulate high-rate discharge behavior of lithium-ion batteries with composite cathode materials, we applied a single-particle model to each cathode material. In the model, we also included the lithium-ion concentration distribution within the electrolyte to calculate the potential profiles in the liquid phase as well as the temperature dependence of both the diffusion behavior of lithium-ions and the charge-transfer rate constant at the solid-electrolyte interface. The potential responses under high-rate discharge were successfully simulated. In this model, the molar flux of each cathode material was determined under the condition that the closed circuit potential of each single-particle should be equal, and the potential distribution in the electrolyte was calculated using a parabolic lithium-ion concentration. The use of approximate analytical solutions for the diffusion equations enabled the reduction of computational time. The validity of the model was confirmed by the experiments using a half-cell of the composite cathode.