摘要 本研究採用Nafion 112為主體的膜電極組(MEA)進行單一燃料電池之實驗及分析，藉著不同的流道設計與操作條件，探討對於質子交換膜燃料電池的性能輸出影響。實驗條件包含不同的流道設計，改變電池溫度，改變增濕瓶加濕溫度，氧化劑之種類，與背壓壓力值的變化等。實驗之結果可以供未來組裝電池堆之參考依據。 由實驗結果可以發現，質子交換膜燃料電池在低溫環境下可以快速啟動並可迅速的達到穩定的輸出電壓。此外，在燃料電池的表面溫度為60℃與增濕瓶的加濕溫度為75℃時可以獲得最佳的輸出功率。一般而言，提昇電池溫度有助於電化學反應速度和離子在電解質膜內的傳遞速度，但是，過高的燃料電池溫度會造成膜電極組內發生乾膜(Dry out)的情況，使得燃料電池的性能下降。提昇增濕瓶加濕溫度則是可以增加膜電極組中的水含量。水含量越高，結合膜的內阻抗越低。但膜電極組內部的水含量過高時，將會發生氾濫(Flooding)的現象，阻礙氫氣、氧氣進入擴散層，降低燃料電池性能。 本研究中，在流道設計上使用四種不同的設計，分別為蛇行式(SFF)，交差式(IFF)，雙交差蛇行式(DISF)，雙蛇行交差式(DSIF)。實驗中發現使用蛇行式流道可以獲得最好的燃料電池性能，其原因在於此流道設計可以讓氣體燃料在流道轉角處也會有部分的燃料強迫進入氣體擴散層，並且使用蛇行式流道設計，其流道內部的氣體使用面積為最大。 Abstract Effects of various flow field designs and operating conditions on the performance of proton exchange membrane fuel cells (PEMFC) are investigated. Nafion 112 membranes are used in the work. Operating conditions studied include humidification temperature, cell temperature, types of oxidizers, and back pressures. In the investigation, four different flow field designs are studied. These include traditional serpentine flow field (SFF), interdigitated flow field (IFF), and inhouse designed double interdigitated serpentine flow (DISF) and double serpentine interdigitated flow field (DSIF). The experimental results show that the SFF has the best performance in the group. This is because the SFF has a large active surface area for the gas flow and also provides better water removing in cell. Especially in the high current density zone, unnecessary water will block the gas passage and thus reduce the cell performance. Results also show that increasing the cell temperature increases the cell performance due to improved electrochemical reaction rate and ion conductivity in the electrolyte. However, if the cell temperature goes too high, the membrane may dry out, and the cell performance will decrease. Another important factor is humidification temperature. A suitable humidification temperature can reduce the resistance of the MEA.
