The Behaviour of Nickel Foam as Flow Field Plate in PEM Fuel Cell Under Mechanical Loads—Numerical Studies

The proton exchange membrane fuel cells (PEMFCs) are clean and affordable alternative energy sources for next-generation mobility. Each cell comprises bipolar plates, gas diffusion layers, endplates, gaskets and a membrane. A fuel cell stack fixed to the mainframe experiences extreme vehicular vibrations due to road unevenness, acceleration, and braking. The vehicular vibrations will result in small relative displacements within the stack. The more recent designs employ metal foams as a flow distributor in the fuel cell, and the low amplitude displacements in the assembly may lead to fretting damage. This study is directed towards understanding the possible relative displacements between components due to vehicular vibrations through numerical simulation. A 3-D finite element model of PEMFC unit cell having the metal foam as flow distributors assembled using eight through-bolts was created and analyzed using the commercial software. The vehicular vibrations mimicked by giving a displacement boundary condition perpendicular to bolt pretension load at one end of the fuel cell while the nut surfaces fixed on the other end. The obtained equivalent stress and total deformations of each component are compared with conventional graphite bipolar plates fuel cell design. The maximum equivalent stress of 110 MPa is noticed in the conventional fuel cell, whereas 94 MPa is observed in the cell with metal foam as flow fields. The relative slippage of 10.4 µm is noticed at the gas diffusion layer (GDL)/metal foam’s interface close to the fixed end. A relative slippage of 3.48 µm is noticed at the aluminium plate/metal foam interface close to the displacement end.