Enhancing the vanadium redox flow battery efficiency by adjusting the electrode configuration

Abstract

The vanadium redox flow battery (VRFB) is being investigated as one of the promising candidates for large-scale energy storage systems. In the present work, the role of electrode shape on a single VRFB cell performance has been studied through a 3D numerical model. The model accounts for the coupling between electrochemistry and fluid mechanic physics. Seven cases of electrode configurations at the same volume size (10 cm3) have been simulated to investigate the overall battery performance. Results from the simulation show that the configuration (case 7) has the best battery efficiency, while the worse one is (case 4) under the same operating conditions, e.g., 71.72% and 63.82%, respectively. Also, the ratio of output to input power for (case 7) is 0.72, while 0.63 for (case 4). In addition, there is an optimal flow rate for each case to get maximum battery efficiency, which means a balance between electrochemical reactions and pumping losses is required. Overall, adopting a thicker electrode (cases 2, 3 and 4) results in lower battery performance due to the poor voltage responses. One feature of the introduced model is its capability to predict the performance of most flow batteries cell configurations.