A Transmission Line Model of Electrochemical Cell's Impedance: Case Study on a Li-S System

Abstract

A transmission line model for approximate description of measured impedance response of selected battery cell types and other electrochemical systems is introduced based on known general solutions from the literature. It contains two branches that can capture general transport features due to migration and diffusion of charge between the electrodes. Importantly, the 4 terminal elements describing the interaction of charge with electrodes are optional. This makes the model applicable for electrochemical systems with asymmetrical electrodes, as commonly met in practical battery cells. In the first part, we briefly revisit several common simplifications frequently found in the literature. Finally, we demonstrate the applicability of the model on three different types of practical cells used in investigation of lithium sulfur (Li-S) batteries.