Sarah Caprio

Transient Studies of a Sodium Sulfur Cell

There is limited data in the open literature for dynamics of an entire cell. With this motivation, a first-principles dynamic model of a sodium-sulfur cell (with beta”-alumina electrolyte) has been developed. The state of discharge (SOD) of a sodium-sulfur cell significantly affects the heat generation rate, rates of electrochemical reactions, and internal resistance. To capture these phenomena correctly, a fully coupled thermal-electrochemical model has been developed. The thermal model considers heat generation due to Ohmic loss, Peltier heat, and heat due to the entropy change. Species conservation equations are written in the sulfur electrode by considering the phase transition and change in the composition depending on the SOD. The electrochemical reactions are modeled by using Arrhenius-type rate equations with temperature-dependent terms and varying species concentration depending on the SOD. Species conservation equations are written in the beta”-alumina electrolyte for the ionic species by considering the change in composition due to diffusion and migration. In addition, the potential distribution, and the cell resistance for this spatially distributed system has been modeled. The physicochemical properties are considered to be temperature-dependent. The model is used to study both charging and discharging characteristics of the cell at varying current densities.

• Shaefer (Caprio) S, Vudata S P, Bhattacharyya D, Turton R, “Transient Modeling and Simulation of a Nonisothermal Sodium-Sulfur Cell”, Journal of Power Sources, 453, 227849, 2020

• Caprio S, Bhattacharyya D, “Transient Studies of a Sodium Sulfur Cell”, Paper 364f, AIChE Annual Meeting, Atlanta, GA, November 16-21, 2014

• Caprio S, Bhattacharyya D, “Transient Studies of a Sodium-Sulfur Cell”, Paper 5c, AIChE Annual Meeting, San Francisco, CA, November 3-8, 2013