本論文主要在研發可長時間運作，性能穩定不易衰退的被動式可攜式直接甲醇燃料電池（DMFC）。由於傳統被動式DMFC的燃料是儲存於陽極反應室內，操作時，陽極甲醇溶液的濃度會一直下降，當濃度降到某一值(約1.5M)以下，性能便會開始下降。若是將甲醇濃度提高，雖可增加降到此值的使用時間，但初期容易發生Crossover，毒化陰極觸媒，且較長時間工作時，甲醇濃度仍會下降，無法維持電池性能穩定不衰退。
為了能達到長時間性能穩定操作，因此維持反應室內甲醇溶液濃度的穩定為必要條件，本論文除改良本實驗室初期的純甲醇補充設計，另外增加水的補充槽。利用控制閘門控制擴散膜面積調整燃料擴散流率，並使用棉線管，將補充的高濃度甲醇溶液輸送至陽極反應室，以補充反應所消耗的甲醇與水。
實驗結果顯示，初始甲醇溶液2M，添加量1.3 c.c.，在185mA (82.2mA/cm2)定電流操作下，沒有補充甲醇時，約15分鐘後性能便開始下降。若補充適當甲醇溶液，則可使性能維持較長時間穩定的操作。但補充過多的甲醇溶液，在長時間後，則會使反應室甲醇溶液濃度持續升高，導致Crossover造成性能衰退。補充過少的甲醇溶液，反應室內甲醇溶液濃度逐漸下降，導致性能下降。所以適當的補充甲醇溶液是長時間穩定操作的重要關鍵。本研究依據操作電流及甲醇溶液的蒸散速率，以適當流量濃度的甲醇溶液補充反應式的燃料，使反應室能維持適當甲醇濃度範圍，以維持電池性能穩定。

In this thesis, a long-term operation direct methanol fuel cell (DMFC) stack with no performance decay is developed and improved. In a traditional passive portable DMFC, the Methanol solution is storage at anode Reaction chamber. The performance will drop after a short period due to the concentration of Methanol solution becoming lower (about 1.5M). Although High concentration of Methanol solution could increase the operation time, but it will couse crossover to poison the cathode Pt particle, and it is unable to keep long-term operation stably either.
In order to achieve long-term operation stably, to maintain the concentration of methanol solution in the anode chamber will be very important. In our fuel supply stack, there are two chambers in the stack to storage methanol and water, and we could control the supplying rate by adjusting the diffusion area to control the diffusion rate of methanol and water. And the methanol solution deliver to anode reaction chamber by cotton tube.
If the anode reaction chamber is filled with 1.3㏄, 2M methanol solution and without any fuel supply, operating on the 185mA constant current (82.2mA/cm2 ). The results shows that the performance begin decay about after 15minutes. If the appropriate amount of methanol and water is supplied, the performance can be steady in a long-term operation.
But if supply too much methanol solution, the concentration in the anode reaction chamber will rise up, and the high concentration will cause crossover poised the cathode catalyst, and the performance will decay. If supply rate not enough, the concentration in the anode reaction chamber will become lower, and the performance will decay after long-term operation. In this study, based on operate current and the rate of evaporation of methanol solution, to supply appropriate supplying rate and concentration of methanol solution to anode reaction chamber, could keep the performance in a steady output.

目錄………………i
圖目錄………………iv
摘要………………vii
Abstract……………… ix
第一章 緒論………………1
1.1前言………………1
1.2燃料電池………………2
1.3文獻回顧………………4
1.4研究目的………………14
第二章 直接甲醇燃料電池理論分析………………16
2.1 DMFC工作原理………………16
2.2.1甲醇於DMFC中之理論消耗量………………19
2.1.2燃料電池質傳現象………………19
2.1.3燃料電池極化現象………………20
2.2直接甲醇燃料電池基本結構………………22
2.2.1膜電極組( Membrane Electrode Assembly, MEA )………………22
2.2.1.1質子交換膜………………22
2.2.1.2電極………………24
2.2.1.3觸媒層………………25
2.2.1.4擴散層………………27
2.2.1.5電流收集板………………27
第三章 DMFC元件製作………………31
3.1甲醇與水儲存槽設計概念………………31
3.2甲醇儲存槽的材質………………32
3.3非均質碳纖維單極板………………33
3.3.1非均質碳纖維單極板製作流程………………33
3.4 MEA製作………………35
3.4.1質子交換膜處理………………35
3.4.2電極預備………………36
3.4.3 MEA熱壓………………36
第四章 實驗方法………………38
4.1實驗材料與設備………………38
4.2實驗步驟………………39
第五章 實驗結果與討論………………41
5.1 實驗條件………………41
5.2儲存室擴散材料之選擇………………42
5.2.1甲醇擴散材料之選擇………………43
5.2.2水擴散材料之選擇………………43
5.2.3不同擴散面積的水擴散量測………………43
5.3補充管路設計………………44
5.3.1棉線擴散速率………………44
5.3.2棉線管製作………………45
5.3.3擴散速率與均勻度………………45
5.4不同負載的甲醇消耗量………………46
5.5 有無補充燃料對性能穩定性的影響………………46
5.5.1初始濃度2M，無補充甲醇………………46
5.5.2定電流不同補充速率對性能影響………………47
5.5.3初始濃度2M，無補充甲醇………………49
5.5.4不同電流最佳燃料供應速率………………49
第六章 結論與建議………………51
參考文獻………………53

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