本研究是運用不同微觀特性之金屬多孔材(metal foam)為質子交換膜燃料電池之流場，搭配金屬雙極板組成單電池，探討在不同電池操作條件(溫度、加溼度等)下，金屬多孔材之孔徑大小與面密度高低對燃料電池性能之影響。 論文中使用金屬雙極板是由於導電性佳、機械強度高、加工方便、容易大量生產，已被視為替代性雙極板材質。一般常見雙極板上因刻劃有流道，隨複雜程度而加工耗時，因此，本研究利用凹槽設計並搭配使用金屬多孔材取代傳統內流道，利用金屬多孔材的導電性佳與氣體滲透性高的特性，進而達成提升電池性能的目標。 研究觀察到孔徑大小與面密度高低是影響金屬多孔材質子交換膜燃料電池性能表現的因子。孔徑大的金屬多孔材，氣體滲透性佳，可以讓氣體擴散性加快，增加與電極上的白金觸媒反應的機會。而面密度高的金屬多孔材則可以降低電池內阻抗的歐姆極化，提升電池性能。由實驗結果可知，金屬多孔材浸泡適當比例的疏水劑後，經過一段時間的烘烤燒結，並配合適當壓力、電池溫度與加濕溫度的操作下，可以讓本研究中的單電池金屬多孔材燃料電池在操作電壓為0.6 V時，產生的電流密度高於2 A/cm2的性能。藉此研究的結果，提供未來金屬多孔材質子交換膜燃料電池的電池堆性能提昇之研發方向。 ;The purpose of this study is to use different micro characters of metal foam as the flow field of PEMFC in metal bipolar plates. The experiments are to explorer the performance of PEMFC in various pore size and area density of metal foam at different (temperature, moisture etc.) test conditions. Metal bipolar plates own good conductivity, high mechanical strength, easy machinery, easy mass production and it has been regarded as the alternative material in bipolar plates. It takes much time to manufacture flow channels in bipolar plates. Therefore, the fillister design with porous metal is used. Besides, take advantage of porous metal that has good performace in conductivity and permeability to supersede traditional flow channels design to achieve the enhancement of fuel cell. In this study, observed the pore size and area density are significant and firmly believed in metal foam PEM fuel cell.The larger pore size of metal foam could affect the gas permeability. In addition, it also provide reactant gases to have better diffusionsive ability and increase the opportunities to get in touch with the Pt catalyst on electrode. As for the area density, we found it can reduce the internal resistance of fuel cell which may increase the performance. From the experiments,the metal foam needs to be immersed in adequated hydrophobic liquid and baked within a period of time.Then use optimum operational conditions (pressure, moisture temperature, cell temp). The results tell us when voltage at 0.6V, the current density is greater than 2 A/cm2 for per single cell.We wish this experimental results and information could be used for development of porous flow channel PEMFC stacks in future.
