Investigation of Solid State Diffusion Coefficient Dependency in Lithium Ion Battery

Abstract

The market for electrified vehicles, particularly for low voltage applications, is expected to witness robust growth during the next decade. The emergence of these vehicles will result in the increasing demand of high-power lithium ion batteries. Understanding battery performance over varying temperatures and current pulses plays an important role in battery design, manufacture, and application. In the lithium ion battery performance simulation, the solid state diffusion coefficient is one of the most significant parameters that affect the battery performance. Solid state diffusion has been previously demonstrated to vary with temperature and state of charge (SOC) [1-2]. Our simulation shows that it also changes with the current density. While the cell ages, the diffusion coefficient decreases as well. With HPPC (hybrid pulse power characterization) data of power cell at different temperatures and different pulse rates, we estimated the diffusion coefficient dependency on current, as seen in Figure1. Using HPPC data from fresh and aged cell, the diffusion coefficient change with time is also summarized.