The crucial role of parallel and interdigitated flow channels in a trapezoid flow battery

Rational flow field design is of great importance in reducing polarization and improving performance of a flow battery. Trapezoid flow field possess great superiority over rectangular flow battery but suffers from local electrolyte stagnation and congestion. Considering that parallel and interdigitated flow channels are widely employed in conventional rectangular flow battery to improve the electrolyte distribution uniformity, radial oriented quasi-parallel and quasi-interdigitated channels are designed to optimize the performance of trapezoid flow battery. Combining the results from hydrodynamic simulation, visualization and charge-discharge experiments, it appears that the flow channels contribute to uniform electrolyte distribution and flow acceleration by controlling the flow pattern in a trapezoid flow field. As a result, the polarization and capacity loss of trapezoid flow battery are reduced. Besides, the effect of parameters like channel depth, electrode porosity on the flow pattern is discussed, which indicates the urgency and importance of further geometrical optimization.