Anode-metal drop formation and detachment mechanisms in liquid metal batteries

TL;DR

This study numerically investigates the formation and detachment of lithium metal droplets in liquid metal batteries, identifying critical currents for droplet transfer and short circuits in different configurations.

Contribution

It introduces a numerical analysis of localised short circuits and droplet detachment mechanisms in Li||Bi liquid metal batteries, considering different interface conditions.

Findings

Critical current for droplet detachment identified

Droplet transfer occurs before complete short circuit

Different behaviors observed in layered and foam-contained lithium

Abstract

We study numerically localised short circuits in Li||Bi liquid metal batteries. In the prototype of a classical, three liquid-layer system, we assume a perceptible local deformation of the Li-salt interface. We find that there always exists a critical current at which a Li-droplet is cut off from this hump, and transferred to the Bi-phase. In a second case, we assume that the molten Li is contained in a metal foam, and that a small Li-droplet emerges below this foam due to insufficient wetting. This droplet is deformed by Lorentz forces, until eventually being pinched off. Here, the critical current is slightly lower than in the three-layer system, and both, a droplet transfer and complete short circuits are observed. Finally, we discuss the relevance of our simulations for experimentally observed short circuits and non-faradaic Li-transfer.