| dc.description.abstract | In this research, the metal foam physical properties of different compressed thicknesses such as permeability, pore size and porosity were measured. Then, these metal foams were applied and matched with different types of flow channel on the high temperature proton exchange membrane fuel cell. Then, these fuel cells did the polarization tests and electrochemical impedance spectrum tests to realize the effect of metal foams and flow channel. Moreover, the operating parameters such as back pressure, air stoichiometry, humidification and temperature were tested to analysis the effects of fuel cell. Finally, the purpose of this study is finding the ways to improve the fuel cell.
The results show that the relation between the permeability and compressed ratio are not linear in low mass flow rate at the measurement of metal foam physical properties. In addition, this relation is similar to the relation between porous area and compressed ratio. Then, it also shows the relation between permeability and porous area. The results of fuel cells show that the higher amount of metal foam protrusion has significantly declining the performance of fuel cell during higher loading operation. The reason is that reaction gas doesn’t easily flow into the catalyst layer to exhaust vapor by some parts of catalyst pores filling up metal foam ribs. Then, the thickness of metal foam does not improve the fuel cell performance but matching with appropriated flow channel make the fuel cell performance increase. The metal foams matched with bigger inlet and outlet channel width has the best performance which is 18.4 % higher than the origin flow channel. Finally, the parameters test show that increasing back pressure, air stoichiometry, humidification and temperature can improve fuel cell performance. However, the higher humidification may make the fuel cell performance decrease. | en_US |