臺灣博碩士論文加值系統

本論文以實驗方法探討膜極組(MEA)製程各項操控參數對於直接甲醇燃料電池輸出功率的影響。文中依序探討壓製MEA時的壓製壓力、溫度與時間等因素對電池性能的影響。此外，並探討MEA壓製完成後的各種處理對電池輸出電壓與功率的影響。
本研究中陰極觸媒含量為4.0 mg/cm Pt Black，而陽極的觸媒含量則為，4.0 mg/cm ，80% Pt-Ru/C。membrane 為Nafion 117，雙極版為本實驗室發展出的非均質碳纖維單/雙極板。自行壓製單電池的MEA質子交換膜面積為3×3 cm ，電極面積1.5×1.5 cm 。研究發現，適當的壓製條件對MEA性能表現影響非常明顯，以120°C、100kg/cm 、90秒的壓製成的MEA，在甲醇濃度3M、自然進氣及室溫操作下，DMFC可以達到功率密度18 mW/cm 。
在實驗的過程中，發現MEA的性能會隨著使用時間增加而逐漸退化。針對此一現象，本研究亦設計一系列實驗檢視性能退化的各種可能原因並加以解決。
圓柱形DMFC是本實驗室發展重點之ㄧ，但由於第一代所使用的MEA以平板式電池為對象無法完全配合6-cell圓柱型電池組，故容易造成電極的剝離並增加接觸電阻；在經過重新自製MEA(電極面積15 cm )以及改造碳纖維束後，總功率目前已提升至135 mW，若6個cell性能均一則可提升至195mW，此電壓與功率可以提供某些可攜式電子產品之需求。

In this research the effects of the fabrication processes of MEA on the output power of a DMFC stack are studied by changing hot-pressing conditions including pressure, temperature and time. Additionally, the effects of the various treatments of the MEAs on the output voltage and power are also studied after the hot-pressing process of MEA is finished.
In the first experimental study the catalyst of cathode is 4.0mg/cm unsupported HP Pt black, Anode is 4.0mg/cm 80% HP Pt-Ru Alloy (1: 1), membrane is Nafion 117, and bipolar plates is heterogeneous carbon fiber bipolar plate developed by our fuel cell laboratory. The MEA for single cell includes the area of membrane 3*3 cm2 the active area of electrode 1.5*1.5 cm2. Under the hot-pressing conditions 120 oC, 100 bar and 90s, the maximum power density can reach a value of 18 mW/cm2 at the conditions of methanol concentration 3 M, air-breathing, and room temperature
After several experiments, we observed that performances of MEAs decayed with time. So we designed a series of experiments to inspect the various possible reasons and try to solve this problem.
The cylindrical DMFC is one of the most important developments in our lab. However, the MEAs made for plate-type DMFC do not fit the cylindrical DMFC stack properly. The electrodes easily pealed off from the membrane and the contact resistance increases after certain periods. So the hot-pressing device had been redesigned to fit the cylindrical DMFC stack. After that the total power of the 6-cell stack with total active area 15 cm2 can reach a value 135 mW. If the performance of each cell of the 6-cell stack is uniform, we expect that the total power of this stack can reach a higher value 195 mW, which can be applied to some portable electronic products.

目錄……………………………………………………………………I
圖目錄…………………………………………………………………IV
論文摘要（中文）……………………………………………………VI
論文摘要（英文）……………………………………………………VIII

第一章. 緒論…………………………………………………………….1
1. 1前言……………………………………………………………..1
1.2 燃料電池的種類 ……………………………………………..2
1.3 文獻回顧……………………………………………………... 5
1.4 研究目的…………………………………………..…………11
第二章　直接甲醇燃料電池基本架構……………………………… .12
　　2.1 前言…..…………………..…………………………………..12
　　2.2 直接甲醇燃料電池之結構…………………………….…….13
　　　　2.2.1 質子交換膜…………………………………………..13
　　　　2.2.2 DMFC陽極………………………………………….…15
　　　　2.2.3 DMFC陰極…………………………………………….16
　　　　2.2.4觸媒載體的影響……………………………………...17
　　　　2.2.5 電極製作方式…………………………….………….17
　　　　2.2.6 膜電極組(Membrane Electrode Assembly，MEA)..18
　　　　2.2.7 雙極板(Bipolar Plate)……………………………18
第三章 直接甲醇燃料電池(DMFC)反應原理與機制…………………21
3.1 DMFC反應原理…………………………………………………21
3.2 DMFC 中的極化現象…………………………………….….….23
3.3 燃料電池的極化曲線(polarization curve)…………….…25
第四章. 實驗材料、設備與方法………………………………………26
4.1實驗材料……………………………………………………..…27
4.1.1 膜極組……………………………………….………….27
4.1.2 單電池………………………………………..…………27
4.1.3 燃料與氧化劑………………………….……………….28
4.2 實驗設備與系統………………………………………………28
4.2.1 MEA壓製設備……………………………………………28
4.2.2 量測設備………………………………….…………….29
4.3 實驗方法………………………………….……………………30
4.3.1 質子交換膜的處理…………………………….……….30
4.3.2 MEA熱壓步驟………………………….………………..31
4.3.3 性能測試……………………………….……………….32
第五章 實驗結果與分析……………………………………………..33
5.1 MEA熱壓實驗…………………………………………………33
5.1.1 熱壓壓力的影響………………………………………..33
5.1.2 熱壓溫度的影響………………………………………..34
5.1.3熱壓時間的影響…….…………………………………..35
5.2 MEA熱壓完成後交換膜含水量對性能的影響…..………..…...35
5.3 不同甲醇濃度對於電池性能的影響……………………..…..36
5.4 穩定性測試……………………………………………………36
5.5 MEA性能退化原因的探討及解決……………………………..37
5.5.1 陰極毒化引起的性能衰退………………………………38
5.5.2 陽極殘存甲醇溶液對性能的影響………………………38
5.5.3 長期放置引起的性能衰退………………………………39
5.5.4 Pt-Ru對CO毒化的抵抗與對性能的影響………………39
5.5.5 稀硫酸對去除陰極CO毒化的效果……………………40
5.6 圓柱形DMFC性能的改善……………………………………41
第六章 結論與建議……………………………………………………44
6.1 結論…………………………………………………….… 44
6.2 未來可進行之研究…………………………………….… 44
參考文獻………………………………………………………………..46




圖目錄
圖2.1 　　DMFC工作原理示意圖………………………….……..48
圖2.2 碳纖維雙極板示意圖…………………………….……..49
圖3.1 質子交換膜燃料電池極化曲線示意圖…………….…..50
圖4.1 單電池零件照片圖………………………………….…..50
圖4.2 單電池基板示意圖………………………………….…..51
圖4.3 Banded Type MEA熱壓模具照片………………….…..51
圖4.4 熱壓完成後之MEA…………………………….….…....52
圖5.1 不同熱壓壓力對DMFC輸出功率的影響……………..52
圖5.2 MEA不同熱壓溫度對DMFC輸出電壓與功率的影響53
圖5.3 MEA不同熱壓時間對DMFC性能影響………….……53
圖5.4 MEA熱壓完成後交換膜含水量對性能的影響.…………54
圖5.5 不同甲醇濃度對於電池性能的影響……………………54
圖5.6 不同負載下，輸出電壓隨時間之變化.……………..…55
圖5.7 不同MEA處理方式之性能比較…….……………...……55
圖5.8 陰極殘存甲醇對性能的影響………………………..…..56
圖5.9 陽極殘存甲醇對性能的影響………………………..…..56
圖5.10 MEA放置引起的性能衰退與處理過後的比較………….57
圖5.11 MEA陰極具有Pt-Ru對抗CO毒化之效應………………57

圖5.12 MEA陰極經CO毒化與處理過後的比較……………….58
圖5.13 圓柱形直接甲醇燃料電池組…………………………..58
圖5.14 暫態測試………………………………………………..59
圖5.15 加工過後之碳纖維……………………………………..59
圖5.16 圓柱型DMFC各單電池電壓、電流密度與平均性能的比較…………………………………………………….…..60
圖 5.17 圓柱型DMFC 6-cell串聯、6個別電池總合以及理想6-cell串聯電壓與功率之比較…………………………………60

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