- 學位論文
金屬發泡材應用於質子交換膜燃料電池內流道之研究
Metal foam as flow field for proton exchange membrane fuel cell
摘要
本研究使用商用高溫型質子交換膜電極組Advent TPS®，搭配傳統蛇行流道石墨板與新型多孔金屬流道板，組成燃料電池，以探討操作溫度、氣體計量比、氣體預熱溫度及氣體加濕溫度對電池性能的影響，且利用交流阻抗分析，觀察電池內部現象的變化，並驗證其相對應之電化學機制。 研究結果顯示，多孔金屬流道具有氣體滲透性高的特性，可以提升氣體的對流及擴散性，增加與白金觸媒反應的機會，且面密度高的金屬發泡材可以有效降低電池內部元件界面接觸阻抗，使電池性能在使用純氧氣於操作電壓0.6 V時，明顯較傳統蛇行流道高出40 %以上。而適度的增加操作溫度、氣體計量比及氣體加濕溫度，有助於提升燃料電池的性能表現。交流阻抗分析所使用的等效電路模型，可以確實的描述燃料電池之電化學機制，輔助我們對於性能的分析及判讀。 在長時間測試部分可以發現，在操作200小時之後開始出現性能下降的趨勢，主要是與觸媒的利用率有關。
並列摘要
This study used a commercial high temperature proton exchange membrane (PEM) electrode assembly Advent TPS®, with a conventional graphite serpentine flow channel and recently developed metal foam flow channel, to assemble a PEM fuel cell. Effects of operating temperature, stoichiometry, gas preheating temperature, humidification on cell performance are investigated. AC impedance analysis is also used to study the changes in various resistances inside the cell, and verify corresponding electrochemical mechanism. Results show that metal foam flow channel having high gas permeability improves gas convection and diffusion, and increase the chance of reaction with the platinum catalyst. The porous structure of metal foam can effectively reduce the contact resistance between the flow plate and carbon paper. The current density at 0.6 V is approximately 40 % higher than conventional graphite serpentine flow channel, when using oxygen as the oxidant. Increasing the operating temperature, stoichiometry, or humidification, improved the cell performance. The equivalent circuit model of AC impedance used in the analysis can describe the electrochemical mechanism of fuel cell. In long time operation test, we observe the performance began to decline after 200 hours, and is mainly related to the decay of catalyst.