| DC 欄位 |
值 |
語言 |
| DC.contributor | 能源工程研究所 | zh_TW |
| DC.creator | 謝仲韋 | zh_TW |
| DC.creator | Chung-wei Hsieh | en_US |
| dc.date.accessioned | 2010-8-27T07:39:07Z | |
| dc.date.available | 2010-8-27T07:39:07Z | |
| dc.date.issued | 2010 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=973208020 | |
| dc.contributor.department | 能源工程研究所 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 本研究將改變電池操作溫度、陰極進氣加濕溫度及陰極進氣計量比等環境參數，再利用直流電化學法所獲得之I-V曲線與電化學交流阻抗法所獲得之等效電路阻抗數值，探討改變電池操作條件對鍍金發泡鎳燃料電池性能之影響。
實驗結果所得之等效電路，將電池阻抗區分為歐姆阻抗、電荷轉移阻抗與質傳阻抗，可分別對膜電極組的濕潤度及導質子的能力、電池內部氧還原反應與質傳效應進行探討；由改變電池操作溫度的實驗結果發現，電荷轉移阻抗與質傳阻抗會隨電池操作溫度的上升皆呈現下降的趨勢，原因在於操作溫度上升，會使得電池內部觸媒活性變高，加快電池內部化學反應。另外，在改變陰極進氣加濕溫度的實驗結果發現，隨電池進氣加濕溫度提高，進入電池內部的反應氣體帶入更多的水分，造成水溢滿(flooding)的現象，降低反應氣體在電池內部的擴散速度，造成質傳阻抗呈現上升的趨勢，且質傳阻抗的上升也導致電荷轉移阻抗也隨之上升，原因為電池內部過多的水分會阻礙氧還原反應的進行。而改變陰極計量比的實驗結果發現，因反應氣體量增加，有助於內部氧還原反應的進行；電荷轉移阻抗會隨著陰極計量比的提高而呈現下降的趨勢。
經直流電化學法與交流電化學阻抗法分析結果，得知本系統之較佳環境操作參數為，電池操作溫度為60℃、陰極進氣加濕溫度為50℃與陰極進氣計量比5時。
最後，當電池石墨流道板改用鍍金發泡鎳取代時，在相同的操作條件下，因為發泡材具有孔洞結構，當反應氣體進入發泡材後，使氣體在發泡材中均勻擴散分部在氣體擴散層，增加反應氣體與電極的接觸面積，使得供氣較普通碳板流道均勻且充足，進而使電荷轉移阻抗下降
| zh_TW |
| dc.description.abstract | The effect of operating parameters of fuel cells such as performance temperature, cathode humidification temperature and cathode stoichiometric feeding on the efficiency of energetic conversion were concerned in this study. The exploration was conducted by evaluation the I-V resulted from DC electrochemical measurement and Electrochemical Impedance Spectroscopy (EIS) measurement by means of numeric estimation of the equivalent circuit. This investigation was focused on a proton exchange membrane fuel cell by using gold-coated nickel foam instead of the traditional graphite flow field plate. .
Simulation of the EIS data by the commercial software Z-view, we obtained the equivalent circuit consisting of ohmic resistance (Rohm) , charge transfer resistance (Rct), constant phase element of the double electric layer (CPE1), mass transfer resistance (Rmt) and the constant phase element of the mass transport (CPE2). The magnitude of the elements was determined individually as follows: Rohm determined by the nature the membrane, Rct and CPE1 determined by the charge transfer on oxygen reduction reaction (ORR) process, Rmt and CPE2 determined by the mass transfer effect.
The resistance for both charge transfer (Rct) and mass transfer (Rohm) decreases with increasing the operating temperature of the fuel cells. This means that the reactivity increases with increasing the operation temperature. It is also found that the resistance for both charge transfer (Rct) and mass transfer (Rmt) increases with increasing the cathode humidification temperature. This implies that higher content of water was carried into membrane and even led to flooding of the membrane electrode assembly (MEA) at higher cathodic humidification temperatures thus causing blocking of oxygen transport. With increasing the cathode stoichiometry, the resistance of charge transfer decreases but that of mass transfer (Rohm) is almost unchanged. This result is ascribed to acceleration of oxygen reduction resulted from sufficient supply of oxygen on the cathode.
According to the results, the optimal operation condition of this system could be summarized as follows: Performing of the fuel cells at 60℃, with cathode humidification temperature at 50℃ and the cathode stoichiometry at 5.
Compared the EIS data between those coming from the fuel cell with gold-coated nickel foam and from that with traditional graphite flow field plate in the performance of proton exchange membrane fuel cell under the same condition, we found that the Rct is much less (0.008Ω)for the gold-coated nickel foam than for the graphite (0.024Ω). It may be ascribed to much more sufficient supply of oxygen through nickel foam than the graphite..
| en_US |
| DC.subject | 質子交換膜燃料電池 | zh_TW |
| DC.subject | 氧還原反應 | zh_TW |
| DC.subject | 金屬發泡材 | zh_TW |
| DC.subject | 電化學交流阻抗法 | zh_TW |
| DC.subject | Electrochemical impedance spectroscopy | en_US |
| DC.subject | Metal fo | en_US |
| DC.title | 鍍金發泡鎳質子交換膜燃料電池之電池操作溫度、陰極加濕溫度、陰極計量比對其性能影響之研究 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Effect of Operating Temperature, Cathode Humidification Temperature, and Cathode Stoichiometry on the Performance of PEMFC assembled with Au-coated Ni-foam | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |