Velocity measurements for liquid metal batteries

Liquid metal batteries could potentially serve as a means of large-scale energy storage. The anodes of such batteries consist of liquid metals, while their cathodes consist of a liquid metal alloy. The electrodes are separated by a liquid electrolyte layer, which needs to be thin to yield a low electrical resistance and a high power output. Motion in a liquid metal battery could cause the electrodes to locally displace the electrolyte and come in contact with each other, thus shorting the battery. An electric current through a battery can subject its liquid constituents to magnetohydrodynamical instabilities. The Tayler Instability (TI) was demonstrated at the Helmholtz-Zentrum Dresden – Rossendorf. In this experiment, the magnetic field outside of a liquid GaInSn column was successfully used as an indicator of the flow [1]. The setup is now being modified to measure the vertical velocity component of the flow with ultrasonic (US) transducers in order to validate numerical simulations. As the US measurement system’s sensitivity to electrical and radio frequency noise from the current source poses an additional challenge, noise suppression mechanisms are being implemented. Furthermore, the relation between the aspect ratio of the column and the critical current, at which the TI first occurs, as well as the interfacial behavior in a two-phase system will be investigated.

Reference
[1] M. Seilmayer, F. Stefani, T. Gundrum, T. Weier, G. Gerbeth, M. Gellert, G. Rüdiger, Physical Review Letters 108, 244501 (2012).