An Electrochemical Model of Lithium Plating and Stripping in Lithium Ion Batteries
Simon Hein, Timo Danner, Arnulf Latz
Abstract
The deposition of a metallic lithium phase on the surface of graphite anodes in lithium ion batteries is a major degradation process and causes inherent safety risks. Despite its importance for battery applications the detection of this so-called lithium plating process during battery charge is very challenging. Therefore, a mechanistic understanding of the Li plating mechanism and the identification of characteristic features in the charge curve of the battery are extremely important. We present an electrochemical model, which enables the description of the deposition and dissolution of a metallic lithium phase in three-dimensional microstructure resolved simulations of lithium ion batteries. The features of this model are demonstrated by simulating the overcharge of a graphite electrode in a half-cell configuration. Simulation results show the typical features of the “stripping-plateau”, which is often observed during discharge after Li plating occurrs. Moreover, a similar feature is observed at the onset of Li plating, which can serve as an indicator for lithium plating in lithium ion batteries during charging, for example, of electric vehicles. Finally, we investigate the impact of an inhomogeneous solid-electrolyte-interphase on the distribution of plated lithium, which highlights the effect of local structural heterogeneities on degradation phenomena.