A computational model for sodium sulfur battery analysis

Energy storage from renewable energy sources is one of the challenging issues of clean energy technologies. Recently, sodium sulfur (Na-S) batteries have gained considerable attention as a viable candidate for large scale energy storage. However, Na-S battery technology comes with the disadvantages of relatively high operating temperature, brittle insulator and safety concerns with regards to temperature management. In this study, a two-dimensional heat transfer model is integrated with a zero-dimensional, transient electrochemical model for Na-S batteries to predict the temperature distribution inside the Na-S battery during a typical operation cycle. Properties required for solving the heat transfer governing equation and electrochemical model, such as electronic and ionic conductivity, species concentrations and thermal conductivity are calculated and updated as a function of time. Additionally, the instant outputs of these combined computational tools for a single sodium sulfur battery, temperature, open circuit voltage, polarization and ohmic losses are used as input parameters for a designed Simulink model to analyze a stack of Na-S batteries. These computational tools aim to support thermal management and to complete the design procedure of storage systems made of Na-S batteries. The present model is tested against experimental results found in literature. Good agreement is achieved between current model and the available experiments.