Electrical safety evaluation of electrolyte leakage of vanadium flow batteries

Leakage of electrolyte of vanadium flow batteries can cause safety risks due to stray voltage forming on the ground or the surfaces of artificial structures. In this paper, an electrical safety assessment approach is developed using a full electrical equivalent circuit model of multi-stack vanadium flow batteries including the cell voltages and ionic resistance of the electrolyte in the flow channels, manifolds and the pipes between stacks and tanks. This approach applies Gauss’s flux law to study the electric field distribution on dielectric surfaces during continuous electrolyte leakage and assesses the risk levels according to the IEC electrical safety standard TS60479. Electrical safety case studies are carried out on scenarios with different battery footing concrete slab dimensions, moisture levels, feet positions, and electrical insulation levels, with safety zones determined. • A method to analyse electrical safety for flow batteries during leakage. • A full equivalent circuit model for a VFB system developed. • Electric field distribution on dielectric surface determined using FEM. • Through-body current calculated to assess the risks.