Metal pad instabilities in liquid metal batteries

TL;DR

This paper analyzes the stability of liquid metal batteries, revealing two types of instabilities during operation, including a known metal pad instability and a newly identified instability caused by electromagnetic interactions.

Contribution

It introduces a mechanical analogy to analyze interface interactions and identifies a new electromagnetic instability in large liquid metal batteries.

Findings

Large batteries are prone to two types of instabilities during operation.

A new instability mechanism related to Lorentz forces was identified.

The study provides insights into stability conditions for liquid metal batteries.

Abstract

A mechanical analogy is used to analyze the interaction between the magnetic field, electric current and deformation of interfaces in liquid metal batteries. It is found that, during charging or discharging, a sufficiently large battery is prone to instabilities of two types. One is similar to the metal pad instability known for aluminum reduction cells. Another type is new. It is related to the destabilizing effect of the Lorentz force formed by the azimuthal magnetic field induced by the base current and the current perturbations caused by the local variations of the thickness of the electrolyte layer.