Performance Model of a Regenerative Hydrogen Bromine Fuel Cell for Grid-Scale Energy Storage

We develop a performance model for a polymer electrolyte membrane based regenerative hydrogen-bromine fuel cell (rHBFC). The model includes four voltage loss mechanisms: ohmic loss through the membrane, hydrogen electrode activation, bromine electrode activation, and bromine electrode mass transport. We explore a large parameter space by looking at the dependences of each of these losses as a function of two “operating parameters”, acid concentration and temperature; and five “engineering parameters”, bromine electrode exchange current density, hydrogen electrode exchange current density, membrane thickness, diffusion layer thickness, and hydrogen gas pressure. The relative importance of each of the losses is explored as both the engineering parameters and operating parameters are varied. The model is also compared to published experimental results on the performance of a hydrogen-bromine cell. By varying engineering parameters and operating parameters within plausible ranges, we project that, with further research, a cell of this design could be developed that operates at greater than 90% voltage efficiency at current densities 700 mA cm--2 in both electrolytic and galvanic modes and that has a peak galvanic power density of 2760 mW cm-2.