Effects of Perforation Location in Gas Diffusion Layers on Electrochemical Characteristics of Proton Exchange Membrane Fuel Cells

Water management is a critical issue for improving both the performance and durability of proton exchange membrane fuel cells (PEMFCs). A gas diffusion layer (GDL), as a porous medium, plays a key role in liquid water removal, reactant supply, and ensuring uniform distribution within the cell. Local perforations in the GDL are known to enhance water management capability. To further improve mass transfer, the effects of the perforation location in the GDL on PEMFC performance were investigated under different flow rates. The performance was compared and analyzed for three cases with GDL on the cathode side: a conventional GDL, a GDL perforated only under the channel, and a GDL with the perforations offset toward the rib by half the channel width. As a result, the offset of the perforations led to improved performance and enhanced uniformity, and the effect of the offset became more significant at higher flow rates. The under-channel and offset cases showed slight performance increases of 3.02% and 3.11% under the cathode stoichiometric ratio (SRc) of 1.2, but more significant improvements of 4.72% and 5.29% were observed under the SRc of 3.0. These results suggest the necessity of considering the flow field when designing a perforated GDL.