Thermal Behavior and Heat Generation Modeling of Lithium-Sulfur Batteries

Abstract

In the past years a lot of research has been carried out in order to develop batteries with very high energy density levels and improved safety, which could fulfill the requirements of next generation electrical vehicle and military applications. This is the case of Lithium-Sulfur (LiS) batteries, which are characterized at present by very high theoretical specific capacity (i.e., 1675 mAh/g) and energy density (2600 Wh/kg) as well as improved safety levels (1). However, their market penetration at a large scale is prevented by their inherent polysulfide shuttle mechanism, which causes fast capacity fade and poor coulombic efficiency (2). Several aspects regarding the behavior of LiS batteries have been studied and are presented in literature. For example, in (3), the authors have analyzed the self-discharge behavior of the Li-S batteries, while in (4), Stroe et al, have performed an in-depth electrochemical impedance spectroscopy characterization of a LiS pouch battery cell. In this work, we fully characterize the thermal behavior of a pre-commercial 3.4 Ah LiS battery cell by performing extended capacity (Figure 1), internal resistance (Figure 2), entropic heat coefficient, heat capacity and emissivity measurements. Based on the obtained results, a model which is able to accurately estimate the reversible and irreversible heat generation is proposed. P. G. Bruce, L. J. Hardwick, and K. M. Abraham, MRS Bulletin, 36(7), 506-512 (2011).Z. Deng et al., J. Electrochem. Soc., 160(4), A553 (2013).V. Knap et al., J. Electrochem. Soc., 163(6), A911 (2016).D.-I. Stroe et al., ECS Trans., 72(12), 13-22 (2013) Figure 1