The Effect of Clamping Pressure on Gas Diffusion Layer Performance in Polymer Electrolyte Fuel Cells

Clamping pressure applied in polymer electrolyte fuel cell (PEFC) assembly is known to have a significant effect on performance. Compression applied on the membrane electrode assembly (MEA) deforms the gas diffusion layer (GDL) and causes a decrease in the GDL thickness, porosity and electrical resistance. These changes in the GDL properties have a significant influence on the MEA performance. In this study, three sets of GDL samples were tested in situ under varied clamping pressure levels to demonstrate the difference in the GDL behaviour with compression, and to optimize the MEA clamping pressure. The paper focuses on the change in the performance of MEAs with various types of GDLs, and relates the properties of the GDL to the behaviour of the MEA under compression. The study discusses the change in GDL compression behaviour with the change in the GDL thickness, density and structure.