Effect of Flow Field Geometry on Operating Current Density, Capacity and Performance of Vanadium Redox Flow Battery

Abstract

Amongst the accessible electrochemical energy storage technologies, vanadium redox flow batteries (VRFBs) are the important candidate for large-scale energy storage due to their elongated life cycle, quick response, ability to go for deep discharge, low cost, and independent energy-power outputs. To date, most of the current research has been focused on new membranes, electrodes, electrolytes and redox chemistries for better VRFB performance in terms of energy efficiencies, however, flow fields and their effects are sparsely explored. Flow fields are a crucial component in VRFB that plays vital role to distribute the electrolytes and hence significantly impacts the mass transport performance. Few flow field geometries have been studied experimentally and computationally for mass transport and pressure drop in VRFB.1–3 Nevertheless, optimal flow fields yet to be defined independently of operating conditions.4 In this research, therefore, we have studied three different flow fields: serpentine, interdigitated and flow through under the identical operating conditions. Effects of flow field geometry on operating current densities and charge/discharge capacities were evaluated. In addition, flow field effect on polarization curves have been investigated. Results show that the performance of VRFBs strongly depends on flow fields and peak power density above 500 mW/cm2 could be achieved even with thick graphite felt electrodes. The outcome of this study should be useful for researcher to further optimize VRFB system for high-performance. Acknowledgement This work is supported by Laboratory Directed Research & Development, Los Alamos National Laboratory.