Modeling the trade-off between performance and pressure drop of bimodal pore size electrodes in vanadium redox flow batteries: Parallel vs. Series arrangement
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引用次数: 0
Abstract
Vanadium redox flow batteries (VRFB) are promising large-scale energy storage system to accommodate the intermittency of renewable energy sources. However, cost reduction is necessary to make the technology more affordable and extend their commercialization worldwide. This goal can be achieved through the design of porous electrodes with enhanced performance and reduced pressure drop. Recently, bimodal pore-size electrodes, featuring interconnected macro and microporous regions, have emerged as a tailored solution for the design of next-generation VRFBs. In this work, the trade-off between performance and pressure drop of bimodal electrodes is examined numerically for two structural configurations: () parallel arrangement (cylindrical macroporous regions aligned in the flow direction), and () series arrangement (cylindrical macroporous regions perpendicular to the flow direction). The model predictions for a flow-through flow field are validated in terms of discharge polarization curves as a function of the feed flow rate and state of charge. Then, a parametric analysis is presented for the two porous structures as a function of the feed velocity, macroporous volume fraction, and microporous pore radius. The results show that microporous regions ( in radius) provide high performance thanks to their large specific surface area, while macroporous regions ( in radius) with a volume fraction around 0.5-0.6 decrease pressure drop. High performance with reduced pressure drop can be achieved with bimodal electrodes arranged in parallel at high stoichiometries and in series at stoichiometries close to one. The latter option is preferred to maximize the energy efficiency at low electrolyte velocity, significantly reducing pumping power requirements.
期刊介绍:
International Journal of Heat and Mass Transfer is the vehicle for the exchange of basic ideas in heat and mass transfer between research workers and engineers throughout the world. It focuses on both analytical and experimental research, with an emphasis on contributions which increase the basic understanding of transfer processes and their application to engineering problems.
Topics include:
-New methods of measuring and/or correlating transport-property data
-Energy engineering
-Environmental applications of heat and/or mass transfer