不同流道設計之透明質子交換膜燃料電池陰極水生成現象探討

Location of droplet formation and water distribution for the various types of flow field designs of PEMFC

陳柏春(Chung-po Chen)

指導教授 ： 曾重仁

國立中央大學/工學院/能源工程研究所/碩士(2008年)

摘要

本實驗藉由實驗方法，利用燃料電池測試系統及以Gore 5621為主體之膜電極組來進行單電池實驗測試分析，研究中我們主要針對在固定開孔率條件下探測不同流場設計對電池特性之影響；在實驗設定上分別探討電池內部自發性生成液態水、改變陰極流速對電池性能影響、陰極加濕與否及電池瞬間負載變化之暫態行為。
由實驗結果可以發現，單蛇、指叉及雙指叉型流道因不同流道設計下，其內部生成水區域分布亦有所差異，其中以雙指叉流道設計擁有均勻性分布而電池性能亦較佳。於電池溫度60oC陰陽極加濕溫度90oC設定條件下，改變陰極流速對於此三種流道設計之電池放電過程皆有性能提升現象。於低溫系統下探討陰極加濕對於單蛇型與雙指叉型流道放電效應具有增進效果，但於指叉型流道卻因本流場設計上在氣流導通方面無前兩者有效分布導致電池性能上無明顯差異。最後於電池暫態切換反應下，可以發現雙指叉型流道擁有較佳的電流增益值，相對地於電位轉換所需切換時間亦較遲緩。由此上結論可知，於此三種流道設計上雙指叉型流道擁有較佳的電池性能特性，原因歸為此流場設計可獲得較均勻之反應氣體分布及具有良好的對流質傳模式。

關鍵字

質子交換膜 ； 燃料電池 ； 流道設計 ； 暫態行為 ； 流道可視化

並列摘要

The purpose of this study is to investigate the effect of flow field design on the performance of PEMFC with fixed open ratio flow fields. Gore 5621 is used in this work. Experiments include the visualization of the droplets formation from cell reaction, effects of cathode flow rate on the water formation and transport, and the transient response of the cell to sudden load change.
The results show that the location of droplet formation and water distribution are different for the various types of flow field designs. The double inter-digitated flow field (DIFF) has the most uniform water distribution and best cell performance among the three flow field designs. For cell temperature of 60oC and humidification temperature of 90oC, cell performances of all three flow fields are enhanced by increasing the cathode flow rate. For low cell temperature cases, cathodic humidification increases cell performance for serpentine flow field (SFF) and DIFF, but not for the interdigitated flow field (IFF). For the transient analysis, results show that DIFF has better current gain but longer response time.
In summary, the cell performance of DIFF is the best of the three flow field designs due to more uniform reactant gas distribution and the convective mass transfer effect.

並列關鍵字

PEM ； Fuel cell ； Flow field ； Visualization ； Transient

參考文獻

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