Performance Enhancements of PEM Fuel Cells with Narrower Outlet Channels in Interdigitated Flow Field

Proton exchange membrane (PEM) fuel cell is a promising renewable energy conversion technology due to its many unique advantages. Among its multiple components, flow field plays an important role in distributing reactants from flow channels to electrochemical reaction sites in catalyst layers (CL).Furthermore, since the reactions only occur at the triple-phase boundary regions where electrons, protons and reactants meet, the transport of oxygen affects the electrochemical active area (ECA) available for reaction. Interdigitated flow fields have been shown to be very effective in transporting reactants to the reaction sites in the CL. In this work, interdigitated flow fields with different outlet channel widths are employed to examine their effects on the cell performance and ECA. Experimental results show that with narrower outlet channels both the ECA and the cell performance increase significantly, at the expense of slight increase in the ohmic resistance.