Physics-based fractional-order model and parameters identification of liquid metal battery

Liquid metal batteries (LMB) with a three-liquid-layer structure at the operating temperature of 300–700 °C, has a broad application prospect of large-scale energy storage. Current physics models of liquid metal batteries have low computational efficiency, leading them difficult to be applied to energy storage systems. Therefore, a physics-based fractional-order model (PB-FOM) is proposed by reducing the order of the kinetic reaction process in this paper. The diffusion in the positive electrode is simplified through Pade approximation, and a dual-electrode cell is designed to acquire the fractional-order formula of mass transfer in the molten salt. Furthermore, this paper provides methods to identify the parameters of physics models based on various experiments. Finally, the established model is validated under varieties of working loads. The results show that the physics-based fractional-order model improves computational efficiency with high accuracy, which can meet the practical application requirements.