Transitions between electromagnetic flow states in liquid metal batteries

High temperature batteries for stationary energy storage typically involve large electrical currents running through liquid electrodes and/or electrolytes. Those currents, in combination with Earth's magnetic field or the magnetic fields produced by the currents themselves, impose forces on the liquid layers that can drive flow and change battery performance. We report on experiments and simulations studying flow driven by electromagnetic forces in the molten electrodes of liquid metal batteries, with and without thermal convection. Our measurements and simulations reveal transitions between azimuthal and poloidal circulation. The implications of both types of flow for battery performance will be discussed.