陰極開孔率與氣體擴散層性質對自然進氣PEM燃料電池性能影響計算分析

Analysis of the effects of cathode opening size and properties of gas diffusion layer on the performance of an air-breathing PEMFC

楊富傑(Fu- Chieh Yang)

指導教授 ： 張敏興

大同大學/工程學院/機械工程學系所/碩士(2010年)

摘要

近年來，以燃料電池作為可攜式電力的研發工作日益受到重視，這些設備都有一個共通點，也就是輕薄短小，因此，燃料電池就必須密集化設計(compact design)，以縮小體積並增加功率密度，當陰極缺乏主動式供氣設備時，整個陰極的設計便極為重要，因此就發展出自然進氣的陰極設計來替代傳統的陰極主動式供氣設備的設計，來達到輕薄、可攜式的目的。
在本論文中，我們將深入探討陰極開孔率與氣體擴散層性質對自然進氣PEMFC性能影響，我們將改變擴散層與觸媒層的接觸角、擴散層與觸媒層的滲透率、GDL的厚度及不同的陰極開孔面積，這四大方向去探討，在研究中發現，當接觸角越大時，排水效果越好，所產生的液態水越容易排除，降低在氣體擴散層內的分佈，若是接觸角小時，氣體擴散層內的排水性差，液態水不易排除，容易造成水氾濫，影響電池性能。開孔率越大時，則疏水性越好，所以液態水飽和度的分佈低，所以電池性能越好。滲透率太小，質傳阻力過大，觸媒層所產生的液態水很難向外傳輸，所以液態水的飽和度會那麼大，當滲透率越大，質傳阻力越小，對液態水的傳輸越好，可以把液態水順利排除，所以電池性能越好，藉由本論文研究後，結果發現接觸角的改變對於電池性能影響最大，GDL厚度的改變對於電池性能影響最小。

關鍵字

質子交換膜燃料電池

並列摘要

In the R&D field, using the fuel cell as the portable power has more and more attention. The lightweight, short and small has common design in recent years. Therefore, the fuel cell shall be use compact design to reduce the size and increase the power density. The cathode design is very important when lack of the active gas supply equipment, thus we develop the natural cathode gas design instead to the traditional cathode active gas design to achieve lightweight and portable.

In this paper, we discuss the impact about the cathode hole rate and the nature gas diffusion layer for the naturally aspirated of PEMFC performance. We also explore from the diffusion and catalyst layer of the contact angle change, the diffusion and catalyst layer of permeability, GDL cathode thickness, and cathode open area directions. In our study, we have those findings: i) if increase the contact angle, the drainage effect is better, the liquid water is easily excluded and reduced the distribution of gas diffusion layer; ii) if decrease the contact angle, the gas diffusion layer is poor, the liquid water is difficult to removed, and the flooding water will affect the performance of the battery; iii) Increasing the open porosity, the hydrophobic is good, the distribution of saturation of liquid water is low, and the battery performance is well; iv) when the permeability is lower, mass transfer resistance and the saturation of liquid water is great, so the liquid water from catalyst layer is difficult to transfer; v) when the permeability is higher, mass transfer resistance is less, and the liquid water can successfully rule out and transfer better, so the battery performance is very well; vi).After exploring, our study result show the contact angle change has the greatest impact and the GDL thickness change has the least impact in the battery performance.

並列關鍵字

PEMFC

參考文獻

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