Anomalous Behavior of Anion Exchange Membrane during Operation of a Vanadium Redox Flow Battery

Vanadium redox flow batteries (VRFBs) are becoming an integral component of renewable energy solutions, microgrids, and backup storage systems. The reduction in cell resistance due to advancements in the electrode and overall component design allows flow cells to operate at higher current/power densities. During discharging of an experimental flow cell at higher current densities, under certain conditions, an unexpected voltage drop and subsequent recovery were observed. Similar effects of voltage drop and recovery have been observed in NiCd and primary lithium–thionyl chloride (LTC) batteries but have not yet been reported for the VRFB in peer-reviewed publications. This study aims to understand the causes behind the voltage drop effect in a VRFB under high power density operation.