臺灣博碩士論文加值系統

本文研究以加入四乙氧基矽烷(tetraethoxysilane, TEOS)為新材料之自製薄膜PTFE/Nafion/TEOS(PNS膜)為PEMFC的新膜材，並探討其於低溫(60℃~70℃)不同入口相對溼度(25%RH~100%RH)操作之性能與長時間放電電壓穩定性並與一般MEA(Nafion112)比較，而在中溫(80℃~120℃)加入一固定背壓20psi或常壓下，於不同入口相對溼度(25%RH~100%RH)下操作，探討其性能與長時間放電電壓穩定性。
自製膜電極組(MEA)於低溫(60℃~70℃)下不論入口相對溼度如何性能皆優於一般MEA(Nafion112)，且長時間放電操作下電壓穩定性亦較一般MEA(Nafion112)好，在電池阻抗方面自製MEA表現亦穩定且阻抗值較低，這是因為新加入基材TEOS所持有的吸附水分子的性質的緣故。在中溫(80℃~120℃)操作部分，發現必須加入一背壓使電池壓力超過飽和蒸氣壓與氣體溶解度增加才能穩定操作。一般MEA在電池超過80℃的狀況已無法順利操作，而自製MEA的性能雖然隨著入口相對濕度的下降而下降，但其長時間放電電壓穩定性可忍受入口相對溼度降低至46.76%RH的操作尚能穩定。於低溫、中溫操作後再次於低溫操作，發現自製膜經過中低溫不同溼度變化長時間約100小時的操作後性能沒有明顯的差異。

The performance and constant-current discharge stability of PTFE/Nafion/Silicate composite membranes(PNS membrane) prepared by impregnating PTFE/Nafion composite membrane via sol-gel processing with TEOS(tetraethoxysilane) is studied for operation at low temperature (60℃~70℃) and medium temperature(80℃~120℃) with different humidity(25%RH~100%RH), back pressure(0, 20psi) in PEMFC and compared with Nafion112 at the same conditions.When operated at low cell temperature (60℃~70℃) with different cell humidiy, PNS membrane performs better than Nafion112 and discharges at constant current more stable than Nafion112, which is due to that TEOS could hold water in PNS membrane. While operated at middle temperature (80℃~120℃),the results shows that PNS membranes couldn’t operate without back pressure, which let the cell pressure exceed saturation pressure and the solubility of hydrogen and oxygen in the liquid water film increase. The performance and stability of PNS membrane decrease with lower inlet relative humidity while a back pressure 20psi is applied, however the stability remains unless the inlet relative humidity lower than 46.76%RH. On the other hand, Nafion112 can not operate stably at cell temperature higher than 80℃, whether a back pressure is applied or not. After operated at low and middle temperature, repeat the experiment at low temperature with inlet gas 100%RH humidified and the results shows that the performances are similar, which means PNS membrane could operate at low and middle temperature with different inlet relative humidity at least 100 hours.

書名頁 i
論文口試委員審定書 ii
授權書 iii
中文摘要 iv
英文摘要 v
誌謝 vi
目錄 vii
表目錄 ix
圖目錄 x
符號說明 xiii
一、緒論 1
1.1前言 1
1.2燃料電池緣起 2
1.3燃料電池簡介 4
1.4研究動機 12
1.5文獻回顧 13
1.6研究目的 17
二、燃料電池結構 19
2.1質子交換膜燃料電池之設計 19
2.2燃料電池內部結構 19
2.2.1膜電極組 19
2.2.1.1質子交換膜 19
2.2.1.2膜材資料 19
2.2.1.3氣體擴散電極 20
2.2.2流場板 21
2.2.3墊片 22
2.2.4集電板 22
三、實驗儀器與方法 23
3.1膜電極組壓合 23
3.2雙極板與集電板CNC加工 23
3.3燃料電池性能測試機台 24
3.4燃料電池性能與放電定性量測方法 25
3.5膜電極組活化步驟 26
3.6實驗目的與步驟 26
3.6.1於Globe機台操作之實驗 26
3.6.1.1低溫操作時電池入口端相對溼度影響之測試 26
3.6.1.2中溫操作時電池入口端相對溼度與壓力影響之測試 28
3.6.1.3於Globe機台操作之實驗條件表 30
3.6.2於CHINO機台操作之實驗 30
3.6.2.1低溫操作時電池入口端相對溼度影響之測試 30
3.6.2.2中溫操作時電池入口端相對溼度與壓力影響之測試 32
3.6.2.3於CHINO機台操作之實驗條件表 33
3.7相對溼度之換算 34
3.8燃料流率之換算 34
四、結果與討論 36
4.1於Globe機台操作之實驗 36
4.1.1低溫操作並改變加溼器溫度之影響 36
4.1.2中溫操作並改變電池溫度與壓力之影響 40
4.1.2.1自製MEA與一般MEA於中溫80℃操作時入口相對溼度100%RH之結果討論 41
4.1.2.2自製MEA於中溫改變電池溫度操作時加入一固定背壓之影響 42
4.1.2.3自製MEA於中溫操作時加入背壓且改變電池溫度之影響 44
4.2於CHINO機台操作之實驗 45
4.2.1自製MEA於低溫操作時改變入口相對溼度之影響 46
4.2.2自製MEA於中溫操作時改變入口相對溼度之影響 48
4.2.3自製MEA於中溫操作時加入背壓且改變入口相對溼度之影響 50
五、結論與建議 52
參考文獻 54

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