Studies On Flow Field Plate Of PEM Fuel Cells And Its Molding Techniques

Proton exchange membrance fuel cell (PEMFC) is recognized as a new alternatveto the present power sources because of its high efficiency, low emission, high energyand power density. Flow field plate is an important part in PEMFC, which distributesfuel and oxidant for PEMFC and provides electronic connection between single cells.Its cost accounts for about 40% of the whole cost of PEMFC, while the high cost ofPEMFC is a key obstacle to its wide application. In addition, the performance of apractical PEMFC power source not only depends on the materials and fabrication ofPEMFC, but is also greatly affected by the distribution of fuel and oxidant. With theabove background, new materials and manufacturing methods for flow field plates areexplored and optimization of structure and channel dimensions in the flow field plateis analyzed in this thesis.1. Using computational fluid dynamics techniques, numerical simulation of flowfield of fuel gas(H2) at the anode of PEMFC was carried out to optimize the channeldimension of the flow field plate of PEMFC to reach maximum fuel gas(H2)consumption. The optimum dimension for channel width, land width and channeldepth were close to 1.5, 0.5 and 1.5 mm respectively, and the maximum fuel gas(H2)consumption at anode is 84.8%. In addition, the fuel gas(H2) consumption of thediscontinuous channels flow field plate is higher than that of the serpentine channeland the parallel channels flow field plate under the same hole rate.2. An efficient and low cost sheet metal forming process for the flow field platewas developed. Based on the elastic-plastic finite element method, numericalsimulation of a production process for metallic flow field plate, which is suitable forlow cost mass production, was carried out. Strain and thickness distribution of theformed thin metallic flow field plate were obtained with the model by FE simulation.The simulated result shows the feasibility of sheet metal forming used to manufacturemetallic flow field plate. Based on this, the design of structure for metallic flow fieldplate has also been done.