Impact of land width and channel span on fuel cell performance

The impact of land width and channel span on fuel cell performance was tested on 50 cm2 flow fields. Combinations of land widths and channel spans of 0.25, 0.5 and 1.0 mm were evaluated. Polarization curves and high-frequency resistance were measured for several humidity levels for each of the flow fields. For performance at high current density, the land width was found to be the dominant factor. Reductions to the smallest size tested (0.25 mm) continued to showed improvement over wider lands. Adequate land fraction (preferably about 50%) needs to be provided to minimize contact resistance.

► A range on land widths and channel spans from 0.25 to 1.0 mm were tested.
► Land width is the dominant factor.
► About 50% land fraction is needed to minimize contact resistance.