Composite Endplates with Pre-curvature for PEMFC (Polymer Electrolyte Membrane Fuel Cell)

A conventional PEMFC (polymer electrolyte membrane fuel cell) stack is composed of multiple stack composed of GDL (gas diffusion layer), MEA (membrane electrode assemblies), and bipolar plates sandwiched in between two thick metallic endplates tightened by bands or tie-bolts as to maintain proper contact pressure on its active area and gasket interface. The proper contact pressure distribution in a stack offers low contact resistance for high energy efficiency and fluid leakage prevention as well. For which, the endplates should have proper structural stiffness.

This work presents a new design of asymmetric composite sandwich endplates which are made of carbon fiber reinforced composite and glass fiber reinforced composite with a pre-curvature generated by the residual thermal deformation, which will yield the required pressure distribution in the stack when the endplates are fastened by the clamping device. Clamping tests were performed with respect to amount of pre-curvature of composite sandwich endplates and the pressure distribution on the stack surface was measured using pressure sensitive films.