Abstract
Proton exchange membrane (PEM) based unitized reversible fuel cells (URFCs) have attractive features as a key component of hydrogen utilization systems. To determine if drawbacks that do not appear in a small-scale single cell of a URFC are significant when a URFC has larger cells in a stack configuration required for commercial applications, a pilot-scale URFC system was successfully operated in both the electrolysis and fuel cell operation modes and both its overall stack performance and the performance variation between cells were measured. No significant drawbacks due to larger cells or stacking were detected in either mode. Local hydrogen pressure at the generation point during electrolysis mode and local flooding during fuel cell mode is examined based on experimental data.
