Effect of GDL compression on pressure drop and pressure distribution in PEMFC flow field

Improving reactant distribution is an important technological challenge in the design of a PEMFC. Flow field and the Gas Diffusion Layer (GDL) distribute the reactant over the catalyst area in a cell. Hence it is necessary to consider flow field and GDL together to improve their combined effectiveness. This paper describes a simple and unique off-cell experimental setup developed to determine pressure as a function of position in the active area, due to reactant flow in a fuel cell flow field. By virtue of the experimental setup being off-cell, reactant consumption, heat production, and water generation, are not accounted as experienced in a real fuel cell. A parallel channel flow field and a single serpentine flow field have been tested as flow distributors in the experimental setup developed. In addition, the interaction of gas diffusion layer with the flow distributor has also been studied. The gas diffusion layer was compressed to two different thicknesses and the impact of GDL compression on overall pressure drop and pressure distribution over the active area was obtained using the developed experimental setup. The results indicate that interaction of GDL with the flow field and the effect of GDL compression on overall pressure drop and pressure distribution is more significant for a serpentine flow field relative to a parallel channel flow field.

► A simple and unique off-cell experimental setup was developed.
► Experimental setup measures pressure drop and pressure distribution in flow field.
► GDL impacts the pressure drop in serpentine pattern and not in parallel flow pattern.
► Clamping pressure on GDL during cell assembly impacts flow uniformity.