Three-dimensional detached serpentine flow field design for redox flow batteries

In the present study, we propose a novel three-dimensional detached serpentine flow field. The flow field applies two staggered serpentine channels to the bipolar plate and electrode (near the membrane side), respectively. The detached inflow and outflow channels aim to enhance convective mass transfer of active species in both in-plane and through-plane directions of the electrode, thereby, leading to enhanced mass transfer, complete electrolyte penetration into the electrode, and reduced pressure loss. The combined effects via the detached flow field lead to the increases of approximately 4.2% and 3.2% in the voltage and energy (pump consumption included) efficiencies of a vanadium redox flow battery cell, respectively, when compared with those of the interdigitated flow field (under the current density corresponding to 100 rnA cm(-2) and flow rate corresponding to 20 mL min(-1)). The experimental results also reveal that the performance of the proposed design is more sensitive to the felt compression and electrolyte flow rate compared to the conventional interdigitated and serpentine flow fields. This is potentially due to the presence of the significant pressure gradient in the through-plane direction of the electrode by using the proposed detached serpentine flow field.