Numerical study on serpentine design flow channel configurations for vanadium redox flow batteries

A flow channel is a significant factor determining the performance of vanadium redox flow batteries (VRFBs). In this study, we use a three-dimensional numerical model to investigate the complexities of the fluid dynamics and electrochemical reactions of VRFBs considering a number of serpentine design flow channels. The results show that cell voltage increases with the reduction in the number of flow channels and increase in the electrolyte flow rate during the discharging process. The higher electrolyte flow rate significantly improves the uniformity of vanadium concentration at both electrodes. We observe that the pressure drop in the VRFB cell decreases with increasing number of flow channels. Moreover, the electrolyte disturbance and flow resistance reduces when the number of flow channels increases, which lead to a smaller pressure drop. As a result, the pumping power derived from the pressure drop decreases with the increase in the number of flow channels. The maximum power-based efficiency calculated for the quadruple serpentine design flow channel at an electrolyte flow rate of 60 ml/min is 97.18%. This serpentine design shows the lowest pumping power and achieves the optimum power-based efficiency. The proposed numerical approach provides comprehensive insights into serpentine design flow channel configurations for VRFBs.