UC Irvine

GDL is an important component of Proton Exchange Membrane Fuel Cell, which provides multi-functions: reactant transport, heat/water removal, mechanical support to the membrane electrode assembly (MEA), and protection of the catalyst layer from corrosion or erosion. GDLs are located between MPLs and bipolar plates, and gases reactants are distributed in the flow field channels and diffuses to the catalyst layer via GDLs. This study is to investigate the deformation or intrusion of GDL upon compression, which alters the channel cross-section and hence the flow conductance for PEM fuel cells. A 3-dimensional finite element model by ANSYS was developed to simulate the GDL deformation under various compression. Deformation or intrusion of GDL will reduce the space of gas flow channel and thus affect the performance of PEM fuel cell. As the compression pressure increases, the GDL intrusion area into the channel increases. The intrusion also increases with the increasing of width of the channel under the same pressure if the GDL-MPL interface is fixed. In addition, if the height of GDL increases, the intrusion of GDL into the channel also increases. When the GDL is 0.2 mm, channel width is 2mm, the pressure is 1 MPa, the intrusion of GDL is 0.05749 mm. When the GDL is 0.3 mm, channel width is 2mm, the pressure is 1 MPa, the intrusion of GDL is 0.08314 mm. To investigate the GDL-MPL interfacial force, the MPL is added to be in touch with the GDL. The simulation shows that the force will change with the increasing pressure. That means they may separate when the pressure increases to a point. In this study, the effect of porous media to the deformation of GDL and the delamination between GDL and MPL are studied. It was investigated in comparison with the traditional hollow channel configuration. Porous media flow field was first proposed by Wang in 2008, which uses porous materials such as metal foams and carbon felts in the channel space and utilizes the multi-functions of porous materials for heat, electron, and flow conductance. It is found that this new porous media flow field reduces the intrusion of GDLs under land compression with reduction dependent on the channel depth and Young’s modulus of the porous material. For a channel depth of 0.3 mm and Young’s modulus of 6.3 MPa, the intrusion was reduced by 21.1%. In addition, the tensile force between GDL and MPL is also depressed by introducing the porous media flow field. For the cases of channel full of porous media, only compressive stress was predicted, which avoids any separation or delamination between the GDL and MPL. The impact on the interfacial force is found to be a function of the channel width, Young’s modulus of the porous material, and land compression. The findings are important to design porous media flow field for PEM fuel cell applications.