Effect of compressive pressure on the contact behavior between bipolar plate and gas diffusion layer in a proton exchange membrane fuel cell

The clamping force during the assembly of proton exchange membrane (PEM) fuel cells has a great influence in the contact resistance between bipolar plate (BPP) and gas diffusion layer (GDL). In this paper, three different types of carbon papers are used as GDL materials. The contact resistance between BPP and GDL is measured under different applied clamping torques. Based on experimental data, a relationship of compressive pressure resulting from the applied clamping torque and contact resistivity is established by the least square method. Based on the commercial code abaqus, a program is developed to predict the contact resistivity. In addition, the changes of contact pressure, contact area, and porosity of GDL are studied. The experimental result shows that the contact resistivity nonlinearly decreases with increasing of the applied clamping torque. The thicker GDL without fillers has a higher contact resistivity. Finite element analysis (FEA) results show that both contact area and contact pressure increase with increasing of the compressive pressure in the same fillet radius of the rib, except that the fillet radius is zero. The porosity decreases with increase of the clamping force. The contact resistivity is consistent with the experimental results. So it can be predicted very well.