Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Introduction
Fluid flow can be both a boon and a curse for liquid metal batteries. One one hand, it may promote mixing of the anode metal into the cathode, preventing it from lingering on the electrolyte-cathode interface. On the other hand, it could momentarily displace part of the electrolyte layer and thus cause a short circuit. The experiment presented here consists of a cylindrical container filled with GaInSn bounded by copper current collectors on the top and bottom, which are attached a power supply unit. The current collector is electrically insulated except for a circular surface whose area is 100 times smaller than that of the bottom current collector. This geometry emulates that of a battery whose cathode consists of a liquid metal drop attached to the top current collector dipped into the electrolyte layer while the anode extends throughout the bottom part of the container. An ultrasound Doppler array was used to perform velocimetry measurements of the electro-vortex flow perpendicularly to the cylindrical axis. In addition, the fluid flow of this setup was also simulated numerically.

Results
While currents ranging from 10 A to 100 A are supplied to the system, the flow pattern appears to consists of multiple stationary swirls, which is in general agreement with numerical results. Additional UDV measurements that are parallel to the cylindrical axis will be performed to obtain a better understanding of the flow structure.

Fig. 1: Velocity profile of the electro-vortex experiment while 100 A are flowing through it. The ultrasound transducers in the array are arranged along the height of the cylinder on the left hand side and measure the radial component of the velocity within one plane.