本論文以數值方法模擬新型非均質碳纖維雙極板與傳統硬質表面雙極板應用在燃料電池反應流體的流動特性。模擬項目包含氧化劑不同進口質量流率及壓力下，平行流道與蛇行流道內氧化劑的速度與壓力分佈，以及反應物供應到肋條下方反應區的難易，以比較新型及傳統雙極板兩者的優劣。
數值模擬結果顯示，由於反應物/生成物可經新板碳纖維間的間隙穿越流入或流出碳纖維束肋條下方的擴散層及觸媒層，故當需要大量氧化劑時，使用新板可有效提昇燃料電池的效能。此外，研究顯示新型雙極板形成的流道，其壓力場分佈較為均勻，反應氣體壓力降亦較小。若用於大尺寸燃料電池，除電流分佈可較均勻外亦可減少供氣所須輸入功。由於燃料氣體可經由新型雙極板肋條內部纖維及多孔碳布進入，並透過對流與擴散的方式傳至觸媒層，故不論平行或蛇行流道，所需供應的氧化劑流量新板皆遠低傳統雙極板。雖然兩種雙極板其流場分佈相似，但新板所需供氣量及流體壓力降皆較傳統雙極板小，壓力與電流分佈也較均勻，因此新型雙極板擁有比傳統雙極板更多的優點。
關鍵字：燃料電池、非均質碳纖維雙極板、硬質表面雙極板

In this thesis the numerical method is adopted to study the flow characteristics of reactants, when the newly developed heterogeneous composite carbon bipolar plate and the traditional hard surface bipolar plate are applied to fuel cells. The simulation in this study includes the distributions of the velocity and pressure of oxidizers flowing in a parallel or serpentine flow channel under several inlet gas flow rates and pressures. The difficulty to supply reactant to the active area under the ribs is also studied in this thesis. From these studies we can understand the strong and weak points of the newly developed bipolar plates and the traditional bipolar plates better.
The simulation results display that the gaseous reactants or products can permeate through the gaps between carbon fibers into or out of active area under the rib, which is formed with carbon fiber bunches. Therefore more reactant gases can be supplied with the heterogeneous carbon fiber bipolar plates than the graphite bipolar plates. In addition, the higher efficiency of fuel cells can be obtained with the new plate, especially in high power density. The pressure distribution in making use the heterogeneous carbon fiber bipolar plates are more uniform, and the pressure drop is also less than the traditional bipolar plates. For large fuel cells the current distribution will be more uniform and the pumping power will be less. The reactant gases can flow through the gaps of carbon fibers and the porous carbon cloth into the catalyst layers by convection and diffusion. So no matter what type of the flow channels used the needed oxidizer is much less with the new bipolar plate than with traditional one. The flow fields of the two types of bipolar plates are quite similar, but the gas needed to supply is also much less with the new plate. Because of the advantages mentioned above, we believe that the heterogeneous carbon fiber bipolar plate is better than the traditional graphite bipolar plate.

Keywords: fuel cell, heterogeneous carbon fiber bipolar plate,hard surface bipolar plate

目錄 ………………………………………………………………………I
圖目錄……………………………………………………………………IV
符號說明………………………………………………………………VIII
論文摘要(中)……………………………………………………………XI
論文摘要(英文) ………………………………………………………XII
第一章 緒論………………………………………………………………1
1.1前言…………………………………………………………………1
1.2燃料電池之種類……………………………………………………2
1.3文獻回顧……………………………………………………………5
1.4研究目的……………………………………………………………9
第二章 質子交換膜燃料電池工作原理………………………………11
2.1 燃料電池的工作原理……………………………………………11
2.1.1 反應效率……………………………………………………12
2.1.2 電池理論燃料消耗量………………………………………13
第三章 傳統硬質雙極板與非均質碳纖維雙極板流場特性比較分
析 ………………………………………………………………15
3.1 傳統硬質表面雙極板……………………………………………15
3.1.1 石墨材質雙極板……………………………………………15
3.1.2 金屬材質雙極板……………………………………………16
3.1.3 碳複合型雙極板……………………………………………17
3.2 非均質碳纖維雙極板……………………………………………17
3.3 非均質碳纖維雙極板優點………………………………………18
3.3 非均質碳纖維雙極板之滲透率…………………………………19
第四章 流場數值模擬…………………………………………………21
4.1 理論分析…………………………………………………………21
4.1.1 基本假設……………………………………………………21
4.1.2 統御方程式…………………………………………………22
4.2 數值模型…………………………………………………………25
4.3 邊界條件…………………………………………………………26
4.4 冷流場簡化方程式………………………………………………27
第五章 模擬結果與討論………………………………………………29
5.1 速度場分佈比較…………………………………………………29
5.2 壓力場分佈比較…………………………………………………34
5.3 不同進口質量流率與流道形式對反應物分佈之影響…………36
5.4 不同進口質量流率對於流場壓力降的影響……………………38
5.5 不同操作壓力對於各流場影響…………………………………38
第六章 結論與建議……………………………………………………40
6.1 結論………………………………………………………………40
6.2 未來可進行的工作………………………………………………42
參考文獻…………………………………………………………………44

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