- 學位論文
陰極水分布對直接甲醇燃料電池性能之影響
The Study of Water Distribution on the Cathode Influence on Single DMFC’s Performance
摘要
本論文以直接甲醇燃料電池標準單電池為基礎，屏除傳統DMFC 需要流 道之設計，以多種不同開孔率之不鏽鋼片組裝一DMFC，觀察其陰極積水情 形與溫度分布。 電池模型以solidworks 3D 繪圖軟體設計燃料電池的尺寸及形狀，陰 極以完全裸空之設計，用以觀察積水及設定排除積水之方法。實驗中首先 以三蛇流道之單電池進行活化多片商用MEA，挑選性能最好之一做為組裝 DMFC進行實驗，以甲醇水濃度測試儀器測試其固定參數做為最佳使用效率， 再以DMFC 水平及垂直分別測試多種不同開孔率之不鏽鋼集電片分別觀察其 積水情況及性能綜合比較，此外，亦對積水情形設計多種水排除方法，分 別於陰極以自然對流、強制對流、覆蓋不同孔隙之吸水材料、探討對電池 性能之影響。 實驗結果，DMFC 在水平時以開孔率為49.8%，3O 之不鏽鋼集電片組裝 效能較垂直時佳，積水情況阻礙與空氣接觸影響最小。垂直時不同集電片 效能較無明顯差異，積水情況集中在下半部分導致性能不如水平，雖然覆 蓋吸水材料可使積水有效分散，但改善情況較水平時不彰。強制對流在垂 直及水平兩種情況時一開始雖然均有明顯改善積水情形，但之後陰極過於 乾燥，內電阻上升，導致效能下降。
並列摘要
In this study, a micro DMFC was designed without the flow channel, and assembled with different opening rate of stainless steel collector to observe the water situation and the cathode temperature distribution. DMFC was designed with Solidworks for size decision, cathode completely bare empty, to observe the stagnant water and set exclude water methods. First of all, activate the MEAs with three-snake-flow-channel of single cells, select as one of the best to assemble with micro DMFC , and experiment with methanol concentration testing equipment to test its efficiency in the use of fixed parameters as the best, and then place the DMFC with horizontal and vertical different opening rate of stainless steel collector to observe the performance of its comprehensive comparison. In addition, a variety of water conditions water for exclusion method in the cathode by air-breathing, forced convection, covering different porous absorbent material were designed to explore the impact on the battery performance. The experimental results showed DMFC got better performance when assembled with opening ratio49.8% collector, situation of stagnant water impede with air less. When DMFC vertical placed, there is no significant difference in performance, stagnant water focus on bottom of DMFC, even covered with porous absorbent material is ineffective. In addition of forced convection, although the outset was significantly improved, the cathode is too dry, internal resistance rises, causing performance degradation.