Effect of calendar ageing on SEI growth and its impact on electrical circuit model parameters in Lithium ion batteries

Abstract

This paper discusses the effect of calendar aging on the growth rate of SEI. It discusses the reasons for the growth of SEI and the implementation of SEI growth in the 3D First Principle Based Degradation Model (3DM) of the battery. The growth of SEI is simulated over a period of 3 years and the impact it has over the terminal voltage and current generated by the battery are plotted and discussed. The results are then applied to the Equivalent Circuit Model (ECM) of the battery to study and identify the impacts that calendar aging and SEI growth has on the parameters of the circuit. The increase in the internal resistance and the decrease in the capacity are also discussed.