Flow-Field Geometry Effect on H2–Iron Redox Flow Battery

Abstract

The redox flow battery is getting intense attention these days as one of the most promising systems to store energy generated from weather-dependent renewable energy sources such as solar and wind energies. In this research, the geometry-related performance of the hydrogen–iron redox flow battery is analyzed with five different flow-field geometries (parallel, serpentine, crisscross, interdigitated, and porous) to determine the best geometry leading to the maximum cell power and fuel efficiency. Diffusion-dominant flow-by mode, convection-dominant flow-through mode, and the hybrid combining both modes are investigated in detail to understand the characteristic transport modes of reactive species and underlying flow physics. In particular, the effects of the flow geometries are analyzed with respect to system-based as well as cell-based performance. It is found that the best net power gain is achieved from the porous flow field, which has excellent fuel utilization and cell power with a low electrolyte supply rate.