Electrical Circuit Models for Performance Modeling of Lithium-Sulfur Batteries

Energy storage technologies such as Lithium-ion (Li-ion) batteries are widely used in the present effort to move towards more ecological solutions in sectors like transportation or renewable-energy integration. However, today's Li-ion batteries arc reaching their limits and not all demands of the industry arc met yet. Therefore, researchers focus on alternative battery chemistries as Lithium-Sulfur (Li-S), which have a huge potential due to their high theoretical specific capacity (approx. 1675 Ah/kg) and theoretical energy density of almost 2600 Wh/kg. To analyze the suitability of this new emerging technology for various applications, there is a need for Li-S battery performance model; however, developing such models represents a challenging task due to batteries' complex ongoing chemical reactions. Therefore, the literature review was performed to summarize electrical circuit models (ECMs) used for modeling the performance behavior of Li-S batteries. The studied Li-S pouch cell was tested in the laboratory in order to parametrize four basic ECM topologies. These topologies were compared by analyzing their voltage estimation accuracy values, which were obtained for different battery current profiles. Based on these results, the 3 R-C ECM was chosen and the Li-S battery cell discharging performance model with current dependent parameters was derived and validated.