Effect of Gas Diffusion Layer Modulus and Land-Groove Geometry on Membrane Stresses in Proton Exchange Membrane Fuel Cells

The electrical functionality of PEM fuel cells is facilitated by minimizing the contact resistances between different materials in the fuel cell, which is achieved via compressive clamping. The effect of the gas diffusion layer (GDL) modulus on the in-plane stress in the membrane after clamping is studied via numerical simulations, including both isotropic and anisotropic GDL properties. Furthermore, the effect of cell width and land-groove width ratio on the in-plane stress in the membrane subjected to a single hygro-thermal cycle is investigated for aligned and alternating gas channel geometries. The results from varying the GDL properties suggest that the in-plane stress in the membrane after clamping is due to a non-linear and coupled interaction of GDL and membrane deformation. The results of the geometric studies indicate that when the gas channels are aligned, the cell width and land-groove width ratio affect the in-plane stress distribution, but do not significantly affect the stress magnitudes. However, when the gas channels are alternating, the cell width and land-groove width ratio have significant effect on the membrane in-plane stresses. The effect of land-groove geometry is qualitatively verified by a series of experimental compression tests.