直接甲醇燃料電池陰極微孔層對性能的影響

Effect of Cathode Microporous Layer on the Cell Performance of DMFC

江和興(Ho-Hsing Jiang)

指導教授 ： 王訓忠

國立清華大學/工學院/動力機械工程學系/碩士(2007年)

https://doi.org/10.6843/NTHU.2007.00394

摘要

近年來，為了提升電池性能已有不少方法是針對於改善陰極水滿溢的問題。這些方法主要可區分為二: (1) 改善流道設計以及 (2) 在觸媒層與氣體擴散層之間增加一層具斥水性的微孔層結構。微孔層主要功能在於能夠讓液態水經由質子交換膜回流到陽極，進而達到減輕陰極水滿溢的現象。
本研究主要目的在於觀察不同孔隙結構的微孔層對直接甲醇燃料電池性能的影響。文章中，我們利用不同粒徑的碳粉以建構出不同孔隙結構的微孔層並觀察到由較細微粒徑的碳顆粒所組成的微孔層能有效降低接觸阻抗。然而，由較大粒徑的碳顆粒所組成的微孔層僅只是在碳布上構成另一層會增加接觸阻抗的結構。性能比較方面，具微孔層的膜電極組其優勢隨著操作溫度的提昇變得更明顯。在低溫操作條件下，具微孔層的膜電極組與未作處理的膜電極組無明顯差異;而在高溫操作條件下，具有微孔層的膜電極組性能明顯優於未經處理的膜電極組。

關鍵字

陰極水滿溢 ； 微孔層

並列摘要

In recent years, many approaches have been presented to improve the cathode flooding in order to obtain better cell performance. These approaches can be categorized as (1) by improving the flow field plate design and (2) by incorporating a hydrophobic micro porous layer (MPL) between the GDL and catalyst layer. The main function of MPL is to promote back-flow of liquid water towards the anode across the proton exchange membrane and alleviates cathode flooding.
The objective of this study is to investigate the effects of different porous structures in MPL on the performance of a DMFC. In this paper, we employ different size of carbon particles to build the MPL with different porous structures and observe that the contact resistance is reduced efficiently by the MPL comprised of finer carbon particles. However, the larger carbon particles just form another layer upon the carbon cloth, which increase the contact resistances. At performance comparison, the advantages of MEA with MPL are more evident as temperature is increased. At low operation temperature, the difference between MEA with MPL and without MPL is not very evident. But the MEA with MPL becomes better than untreated MEA at high operation temperature.

並列關鍵字

cathode flooding ； micro porous layer (MPL)

參考文獻

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