Abstract: When designing a cell stack and developing an operational strategy for proton exchange membrane fuel cell, it is critical to characterize the local current, water and heat. To measure distributions of current density, relative humidity and temperature for both anode and cathode simultaneously along the straight parallel flow channels, this paper uses a segmented tool based on the multilayered printed circuit board flow field plates with embedded sensors. In this study, two kinds of experimental operations of fuel cell reactants are carried out for comparison: the co-flow operation with identical gas flow direction of hydrogen and air and the counter-flow operation with opposite gas flow directions. The detected relative humidity (RH) distributions of both anode and cathode indicate that the asymmetry of RH distribution at two sides of the membrane in counter-flow operation is better at holding water inside the fuel cell compared with the co-flow operation. The in situ measured performance distributions show that segments around the middle of the fuel cell contribute the highest current in counter-flow operation, while for co-flow operation, the current peak locates near the outlet of reactants.

Key words: Proton exchange membrane fuel cell · Segmented cell · Local relative humidity · Local temperature · Current , distribution