This study examines the effect of increased channel length on the distribution of flow gases and cell performance in an interdigitated flow-field PEMFC. A numerical model was used to simulate the pressure distribution and gas flow in 5 cm and 25 cm channel length interdigitated flow fields that have eight channels with fixed channel and land widths of 1 mm. The results show the distribution of flow under land areas (cross flow) is subject to maldistribution in the longer cell while the shorter cell produces relatively homogenous cross flow along its length. An experimental test cell was designed to run with the same channel lengths, under similar conditions to those modeled. Inlet pressure data was recorded to account for parasitic pump losses, used to calculate net system power curves. Results show that a shorter channel interdigitated flow field may produce both higher maximum power and limiting current densities compared with longer cells.

Keywords: PEM fuel cell, Interdigitated flow field, Parallel flow field, Cross flow