Novel Interdigitated Flow Field with a Separated Inlet and Outlet for the Vanadium Redox Flow Battery

Thevanadium redox flow battery (VRFB) is considered as a promisingenergy storage technology to solve the environmental problems of globalwarming. The optimizations should be carried out before the large-scalecommercialization of the VRFB, and the flow field greatly affectsthe battery performance. In the paper, a two-sides interdigitatedflow field (IFF) is designed for improving the mass transfer behaviors,and a three-dimensional numerical model is established to predictthe charge-discharge process of the VRFB. The charge-dischargevoltage, overpotential, concentration distribution, and uniformityfactors are analyzed to evaluate the battery performance of differentflow field designs (case 1, the conventional IFF; case 2, the two-sidedIFF; and case 3, the two-sided IFF with a high contacting area). Incomparison to cases 1 and 2, the VRFB with the case 3 design possessesthe highest discharge voltage and the lowest charge voltage. For thedistribution uniformity factor of V2+, case 2 is 5.5% higherthan case 1 and case 3 is 17% higher than case 1. The two-sided IFFoutputs the highest net power. Furthermore, case 3 can acquire 85.6%system efficiency, while the efficiency of case 1 is 84.5%, whichshows that the two-sided IFF is more suitable for the large-scaleVRFB.