平板式固態氧化物燃料電池雙極板流道設計對發電性能的影響分析

Abstract

燃料電池是一種高效率且乾淨無污染的發電方式。而固態氧化物燃料電池(SOFC) 屬於高溫型燃料電池(500-1000□C)，配合熱電共生系統(CHP)，其發電效率的理論值更可以達到90%以上，是相當有競爭力的能源技術之一。 本研究在探討平板式固態氧化物燃料電池雙極板的流道設計對單電池整體效率以及燃料使用率的影響。並藉由數值分析的方式模擬來改善設計，以補足實驗所無法觀察到的現象。我們利用商用計算流體力學(CFD)程式”Ansys-Fluent”中的SOFC模組進行單電池模擬。測試電池在各種不同的氣體流道設計時，對電池運作的整體與細部的變化和影響。其中包含流場分析，溫度分析，電化學分析。並設計出最適合的電池堆方案，使電池運作時的效率能夠增加，提高燃料使用率，降低系統成本。 結果顯示，當參考2011年William J. Sembler等人[1]研究的材料參數來分析時，使用以雙極板對角線為流場方向的新型設計(Type C)將可比傳統的逆向流流場設計(Type A)增加12%的電池效率與14.6%的燃料使用率。其設計更能減少材料成本與電池堆的系統複雜度。

Fuel cells have demonstrated very high efficiency and are also much less harmful impact to the environment in general. Among these, solid oxide fuel cell (SOFC) has been considered as one of the promising energy technologies due to its high efficiency (up to 90%) that can be achieved by hybridizing with combined heat and power (CHP) system because of its operation at high temperature (500-1000 □C) In this thesis, we are interested in exploring the effect on efficiency and fuel utilization by changing flow channel design of the planar solid oxide fuel cell stack. Through numerical investigation for improving the design, we can obtain several important operating parameters which can not be obtained through experiments. Therefore, we employ a commercial Computational Fluid Dynamics (CFD) code, named Ansys Fluent, by using its SOFC module in the current study. These studies include flow analysis, thermal analysis, and electrochemical analysis. The results show that a new design, named Type C, in which the gas flow is directly across the interconnects diagonally, 12% and 14.6% of power density and fuel consumption, respectively, are found as compared to the counter flow design presented in Sembler et al. [1].