傳統的石墨雙極板，兼具進氣、排水、集電、散熱等四大項功能，但 石墨流道板價格昂貴、加工時容易脆裂、導電性差及體積大等材料特性局 限，且流道設計其擴散面積與集電面積是會互相牽制的，因此，本研究著 重在分析石墨流道板所必須提供的四大項功能，而改用其他便宜容易大量 生產的元件。進氣與排水使用塗佈疏水高分子的發泡鎳。集電使用鍍銀的 金屬擴張網。集電板則擔任散熱的功能及提供單電池所須的機械強度。疏 水墊片能阻隔水氣腐蝕銅板與金屬擴張網的接觸面，並吸收各金屬元件溫 度變化下產生的熱膨脹變化。 本研究是藉由不同材質和不同孔大小的金屬網及不同操作條件下，來 探討金屬網型相較於石墨流道板對於質子交換膜燃料電池的性能輸出影 響。在單電池高電流輸出時,金屬網加金屬發泡材較石墨板有更大更密集的 接觸面積，因此有較佳的電子傳導能力；含疏水高分子的發泡鎳相較石墨 板有更佳的氣體擴散能力和排水力；集電板搭配金屬網又提供良好的散熱 能力。因此，在單電池相同操作條件下， 此便宜複合式模組的設計其高功 率輸出性能已高出傳統石墨流道板。本研究對如何平衡好的氣體擴散與高 的電子傳導並且在高電流密度時，減少陰極水氾濫的課題上，作不同材料 及設計變化之研究。 Traditional bipolar plate is made of graphite and has four major functions: fuel supply, water removal, electron conduction, and waste heat removal. However, graphite is easy to break due to its brittleness. The machining cost is high. It also accounts for more than 60 percent of the volume and weight of a fuel cell stack. In this work, we use a new design to separate the four functions of the bipolar plate. The flow channels are replaced by a hydrophobic metal foam that take care of fuel supply and water removal. A silver-plated metal mesh is used to conduct the electrons. A metal plate is used to conduct heat and provide the mechanical strength. A hydrophobic plastic sheet is used to protect the metal plate from corrosion and also acts as a buffer material for thermal expansion of metal components when heat is produced. In this study, the performance of the newly designed single cell is compared to that of traditional cell with graphite polar plate. Effects of different material and treatment on the metal mesh are also studied. Because the metal mesh has smaller resistance and the metal foam provides better reactant supply, so the new design has better performance than traditional one, especially at higher electric loads.
