AC Impedance Technique Applied to the Diagnosis of Metallic Bipolar Plate Degradation Behavior for Proton Exchange Membrane Fuel Cells (PEMFCs)

• Main Authors: Lin,Chien-Hung, 林建宏
• Other Authors: Hou,Kung-Hsu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/93642606495038661002

博士 === 國防大學理工學院 === 國防科學研究所 === 100 === These bipolar plates that are made from 5052 aluminum, coated with various coating layers to enhance the corrosion resistance and conductivity. The single cell test is executed by the performance and long-term experiment. The effect of the metallic bipolar plate degradation behavior for the PEMFC (Proton Exchange Membrane Fuel Cell) is analyzed in this experiment. These bipolar plates with gold coating layer possessed the corrosion-resistance and good conductivity. The decay rate of bipolar plate under the constant current test is less than 10％ for 300 hours operation. Even the local corrosion and oxide film led to the decay of the PEMFC which can be inferred from above result and the AC impedance analysis. The equivalent circuit parameters show the minor change form the experiment result. Furthermore, the aluminum blank can not shield the substrate effectively. The decay rate for the constant current test is higher than 10％ for 60 hours operation. The resistance in high frequency varied from 19 mΩto 36 mΩ. It is obvious that the surface modification is important to the metallic bipolar plate. The coating layer with (Polytetrafluoroethylene, PTFE) particle enhances the hydrophobic ability with minor change in the roughness. This microstructure decreases the corrosive rate on the bipolar plate. Finally, these above results not only establish the product water analysis for PEMFC, but also contribute to evaluate the key factors for improving cell performance and provide data for the cell preliminary design.