Thermal effects in liquid metal batteries
During charge and discharge of a liquid metal battery, heat will be release by Ohmic heating. The heat will be transfered by convection, conduction and radiation. A thermal management ensures that the global cell temperature stays in the desired range (fig. 1).
The electrolyte layer (consisting of a molten salt) has the highest resistance of the three phases; fig. 2 shows a typical temperature profile. The bottom metal will be heated from above - it will be stably stratified. The upper metall will be heated from below - convection will set in.
Typically, thermal convection cells will appear in the upper metal layer and the electrolyte. At HZDR we study Rayleigh-Bénard convection with the objective of enhancing mass transfer and increasing the efficiency of liquid metal batteries. For that purpose we developed recently a multiphase solver using the Oberbeck-Boussinesq approximation for describing thermal convection in all three liquid layers.
- Ashour, R.; Kelley, D.; Salas, A.; Starace, M.; Weber, N.; Weier, T.
Competing forces in liquid metal electrodes and batteries
Journal of Power Sources 378(2018) 301-310
- Personnettaz, P.
Assessment of thermal phenomena in Li||Bi liquid metal batteries through analytical and numerical models
Master thesis, Politecnico di Torino (2017)