Numerical analysis of modified channel widths of serpentine and interdigitated channels for the discharge performance of vanadium redox flow batteries

A flow channel is a key component of vanadium redox flow batteries (VRFBs), which distribute the electrolytes in the porous electrodes and improve the battery performance. A three-dimensional VRFB model with four different flow channel designs is proposed in this study, which are serpentine and interdigitated flow channel designs with 2 mm and 5 mm channel widths. The effects of the proposed flow channel designs on convective mass transport, flow distribution, and discharge voltages are investigated in detail. The porous electrode constituting the active area of VRFB provides stable electrochemical performance through uniform supply of electrolyte. The reactivity by mass transfer in electrodes is characterized through the concentration distribution of active ions. The increase in system pressure and flow rate is strongly related to the electrochemical performance. The resulting velocity vector of active-ions permeating into the porous electrode directly affects the electrochemical performance. The results reveal that the serpentine 2 mm flow channel exhibits higher discharge voltages as compared to other flow channel designs. The serpentine 2 mm flow channel shows superior performance and higher pressure drops as compared to other flow channel designs for all the operating conditions tested. This numerical study provides a comprehensive understanding of the flow channel design configurations for VRFBs.