The Surface Morphology Effects of a Metallic Bipolar Plate on the Interfacial Contact Resistance of a Proton Exchange Membrane Fuel Cell

This article presents a fundamental study of the surface morphology effects of a metallic bipolar plate on interfacial contact resistance using both finite element method (FEM) analysis and experimental tests. The surface texture of a metallic bipolar plate is treated both chemically and mechanically. Both these treatments are used to increase the surface roughness of the metallic bipolar plate. The results show that the interfacial contact resistance is strongly related to the interfacial variations in the contact area. The FEM analysis indicates that when the surface roughness is above 8 m, the interfacial contact area is 2.5 times larger than in the cell with an untreated bipolar plate. In addition, the experimental tests show that the contact resistance reduces significantly by approximately 65% when the surface roughness is above 10 m. The single cell performance tests show that the current density of the treated cell increases by 17% over that of the untreated cell. Furthermore, the ohmic losses of the treated cell are lower than those of the untreated cell. This shows that the mass transport losses of a cell can be reduced by the rough surface of the bipolar plate, especially in the rib area.