Experimental studies of permeability measurement and hydrodynamics study of all-Vanadium redox flow battery

Abstract

In this paper, we present hydrodynamic studies of conventional, parallel and serpentine flow field and electrochemical studies of conventional flow field pertaining to all-vanadium redox flow batteries. Computational fluid dynamics (CFD) simulations of electrolyte flow distribution in the flow fields have been carried out; these show that a non-uniform flow distribution is established in parallel flow field and that a very large pressure drop occurs in conventional flow; serpentine flow fields offer optimal solution in terms of nearly-uniform flow distribution with reasonably low pressure drop. The key to both pressure drop in conventional flow fields and under-the-rib convection in serpentine flow fields is the permeability of the electrode under compression. These have been determined experimentally for two commercially available carbon felts. In-situ measurements of pressure drop have also been conducted with both felts in serpentine flow fields. The result show that SGL carbon felt gives 55% higher-pressure drop as compared to the carbon felt from Alfa Aesar. Electrochemical studies with the conventional flow field show this is compensated by higher energy efficiency with the SGL carbon felt.