臺灣博碩士論文加值系統

摘 要
本研究的目的在於探討操作變因對DMFC的I-V曲線與開路電位的影響，操作變因包括改變電池的溫度、甲醇濃度、陰極進料的種類（氧氣或空氣）與其流量。
實驗結果顯示，電池效能隨著溫度升高而增加；最佳的甲醇操作濃度為2M，越高濃度的甲醇於高溫操作下，甲醇滲透的情形會越嚴重，增加陰極的流量有助於電池效能的提升，但是當流量增加到一定值，流量再增加對電池性能幫助是有限的。
開路電位方面，在陰極無論使用空氣或氧氣，陰極流量的增加有助於開路電位值的提升，於電池溫度與甲醇濃度對開路電位的影響中，使用低濃度的甲醇時，電池溫度對開路電位的影響較甲醇濃度為大，當甲醇濃度增加時，則甲醇濃度對開路電位的影響較電池溫度為大，使用空氣時其影響的轉折甲醇濃度為0.75M，而使用氧氣時，甲醇操作濃度則提升到2M。

關鍵字：直接甲醇燃料電池、開路電位

Abstract
The objective of this study is to investigate the effects of various operating parameters on the performance of the I-V curves and open cell voltages of the DMFC. The operating parameters included cell temperature, methanol concentration and cathode fuel species (oxygen or air) and its flow rates.
The experimental results showed that cell performance was enhanced by increasing the operating the temperature and the operating optimal methanol concentration was 2M. At high temperature, when higher concentration of methanol was used, more methanol crossover was observed. The cell performance was increased with cathode flow rate up to a certain value, after which the cathode flow rate had no significant effect.
The effects of cell temperature, methanol concentration and cathode flow rate on the open circuit potential (OCV) were also studied. By using air or oxygen at the cathode side, increasing cathode flow rate was indeed useful for the OCV. On the effects of cell temperature and methanol concentration on the OCV, when using low methanol concentration, the cell temperature had more effect on the OCV than the methanol concentration. On the other hand, when using higher methanol concentration, the methanol concentration had more effect on the OCV than the cell temperature. The transition point of the operating methanol concentration by using air was 0.75M, while 2M for oxygen at the cathode side.

Keywords: Direct methanol fuel cell; Open circuit voltage

中文摘要 -------------------------------------------------------------------------I
英文摘要 -------------------------------------------------------------------------II
目錄 ------------------------------------------------------------------------------III
圖目錄 --------------------------------------------------------------------------VII
表目錄 -------------------------------------------------------------------------XIII

第一章 概論 --------------------------------------------------------------------1
1.1概論 ------------------------------------------------------------------------1
第二章 文獻回顧 --------------------------------------------------------------2
2.1 直接甲醇燃料電池簡介 -----------------------------------------------2
2.1.1 甲醇的使用方式與進料型態 ------------------------------------3
2.1.2 直接甲醇燃料電池的工作原理 ---------------------------------4
2.1.3 DMFC的應用 ------------------------------------------------------ 6
2.2 直接甲醇燃料電池的單電池結構 -----------------------------------7
2.2.1 膜電極組（MEA）的結構 -----------------------------------------8
2.2.1.1 擴散層 ----------------------------------------------------------8
2.2.1.2 電極觸媒材料 -------------------------------------------------9
2.2.1.3 觸媒層 --------------------------------------------------------12
2.2.1.4 質子交換膜 --------------------------------------------------13
2.2.2 雙極板與流道 -----------------------------------------------------15
2.3 膜電極組（MEA）的製作 ---------------------------------------------17
2.4 極化現象（Polarization） ----------------------------------------------18
2.5 甲醇滲透（Methanol Crossover） ------------------------------------19
2.6 開路電位 （Open Circuit Voltage, OCV） --------------------------23
2.7 DMFC之性能分析 -----------------------------------------------------25
2.8 研究動機與目的 -------------------------------------------------------30

第三章 實驗方法 ----------------------------------------------------------31
3.1 藥品及耗材 -------------------------------------------------------------31
3.2 儀器設備 ----------------------------------------------------------------32
3.3 MEA的製備 -------------------------------------------------------------33
3.3.1 Nafion membrane 的前處理 ------------------------------------33
3.3.2 陰、陽極電極片的製作 ------------------------------------------34
3.4 DMFC單電池性能測試 -----------------------------------------------36
3.4.1 單電池組裝 --------------------------------------------------------36
3.4.2 單電池放電性能測試 --------------------------------------------38
3.4.2.1 極化曲線(I-V curve) -----------------------------------------38
3.4.2.2 開路電位(Open Circuit Potential) -------------------------40

第四章 結果與討論 ---------------------------------------------------------41
4.1 電池溫度對DMFC的影響 -------------------------------------------41
4.1.1 陰極使用氧氣 -----------------------------------------------------41
4.1.2 陰極使用空氣 -----------------------------------------------------48
4.2 甲醇濃度對DMFC的影響 -------------------------------------------52
4.2.1 陰極使用氧氣 -----------------------------------------------------52
4.2.1 陰極使用氧氣 -----------------------------------------------------55
4.3 陰極流速對DMFC的影響 -------------------------------------------58
4.2.1 陰極使用氧氣 -----------------------------------------------------58
4.2.1 陰極使用空氣 -----------------------------------------------------64
4.4開路電位 -----------------------------------------------------------------68
4.4.1 陰極流量對開路電位的影響 -----------------------------------68
4.4.1.1 陰極進料為空氣 --------------------------------------------68
4.4.1.2 陰極進料為氧氣 --------------------------------------------73
4.4.2 甲醇濃度對開路電位的影響 ----------------------------------77
4.4.2.1 陰極進料為空氣 --------------------------------------------77
4.4.2.1 陰極進料為氧氣 --------------------------------------------81
第五章 結論 ------------------------------------------------------------------85
5.1 結論 ----------------------------------------------------------------------85
5.1.1 電池溫度對DMFC的影響 -------------------------------------85
5.1.2 甲醇濃度對DMFC的影響 -------------------------------------86
5.1.3 陰極流速對DMFC的影響 -------------------------------------87
5.1.4 開路電位 -----------------------------------------------------------88
5.1.4.1 陰極流速對開路電位的影響-------------------------------88
5.1.4.2 甲醇濃度對開路電位的影響-------------------------------88

參考文獻 ------------------------------------------------------------------------89

附錄 ------------------------------------------------------------------------------91

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