High-accuracy dynamic model of high-temperature sodium-sulfur stationary battery

The increasing demand for stationary energy storage has put alternative battery chemistries in the spotlight. Sodium-based technologies appear to be a cost-effective and sustainable option, potentially competing with lithium-ion batteries. However, the long-term reliability, essential for stationary storage services, requires an understanding of performance degradation under realistic operating conditions. In this work, we present a physics-based dynamic equivalent circuit model for Sodium-Sulfur batteries, developed to capture the complexity of system behavior and examine the processes contributing to battery aging. In this way, existing battery models completely overlook the dynamic behavior of sodium‑sulfur batteries. The presented model is validated against real measurements taken at the HUN-REN Centre for Energy Research, where a Sodium-Sulfur battery was recently commissioned. By comparing the performance of the model across various power profiles, its ability to capture the complexity of the entire system is evaluated. Overall simulation results are within ± 1% for most scenarios. The presented work was developed under the 2021–2.1.1-EK funding scheme.