Electrochemical Impedance Spectroscopy-Based Electric Circuit Modeling of Lithium–Sulfur Batteries During a Discharging State

Lithium-ion batteries are characterized by having a very good performance in terms of efficiency, lifetime, and self-discharge, which allowed them to become the major player in the electric vehicle (EV) applications. However, they were not able to totally overcome the EV range anxiety. Thus, a research is carried out nowadays to develop batteries with even higher gravimetric energy density, which should allow a substantial range increase. One of the technologies, which should be able to meet the range requirements is the lithium-sulfur (Li-S) battery. Thanks to the extensive research and development efforts, these cells are close to enter the market, being evaluate in various projects. In this paper, we have proposed an electrical circuit model for a Li-S pouch cell, which was parameterized based on extensive electrochemical impedance spectroscopy measurements. The developed model was verified using static and pulse discharge profiles, showing a good accuracy in predicting the voltage of the tested Li-S battery cell.