DSpace community: 能源研究中心

最佳化固態氧化物燃料電池堆設計測試及模擬分析;Simulation and Analysis of Planar SOFC for Optimization

title: 最佳化固態氧化物燃料電池堆設計測試及模擬分析;Simulation and Analysis of Planar SOFC for Optimization abstract: 本計畫目標為採用實驗與數值模擬方法，分析平板式固態氧化物燃料電池(Solid Oxide Fuel Cell, SOFC)之傳輸現象及其效應對電池效能之影響。針對：(1)流場均勻度對電池性能與溫度分佈之影響；(2)電極材料孔隙特性對擴散極限和輸出功率之影響；和(3)單電池較佳操作條件之測試與模擬等三大研究重點，進行深入探討。有關流場均勻度方面：我們擬利用雷射光學流場量測技術，分析影響流場均勻度的因素，如進氣端之流場特性或流道進口處之迴流特性，亦將嚐試藉由新式電池堆設計來克服密封問題。此外，我們將建立單電池性能測試平台，系統化測試不同設計單電池之輸出功率以及溫度分佈，所獲之結果對於抑制電池元件熱應力將有所助益。有關多孔電極傳輸現象分析方面：我們將建立數位質點影像測速儀與折射率契合技術，定量量測不同孔隙度之多孔介質，含以圓球陣列實驗模擬之多孔介質、常用之SOFC陶瓷材料、以及鎳網內部的傳輸機制，同時搭配以實驗數據為基礎所建立之反應流數值模式，以分析SOFC陽極與陰極之傳輸極限，進而評估減緩電池濃度極化的方法。有關操作條件較佳化測試方面：提升SOFC的燃料使用率可有助於降低發電系統的成本，故我們將藉由單電池測試或數值模擬，尋找可平衡兼顧功率密度與燃氣使用率之燃氣雷諾數的操作範圍。最後，本計畫所進行之電池性能測試，其操作條件、單電池材料與幾何形狀皆以核能研究所發展中之SOFC為參考依據，故所獲得的研究成果對於協助核研所延伸SOFC的壽命以及降低系統成本，應會有具體幫助。 ; This proposal aims to analyze transport phenomena in planar solid oxide fuel cell (SOFC) using both experimental and numerical approaches. Three key issues will be studied: (1) Effects of flow uniformity on cell performance and temperature distributions; (2) the sensitivity of porous parameters to the diffusion limitation and the power density; and (3) test and simulation of optimal operating conditions for single SOFC. For the issue of flow uniformity, non-intrusive laser optical measuring technique will be applied to analyze various flow patterns, such as the flow field in the feed header and the flow recirculation at the entrance of the flow channel. We will also attempt to propose a new stack structure for further improving the sealing problem of planar SOFC. Furthermore, a simple SOFC test platform will be established to systematically measure the current-voltage curves and temperature distributions of single cells with different degrees of flow uniformity and then study its effects on cell performance. These results should be useful for reducing the unwanted thermal stress on cell components. For the analysis of various transport phenomena in planar SOFC, velocity distributions in various porous media, including the packed bed of spheres, the commonly-used ceramics of SOFC, and Nickel mesh will be measured using digital particle image velocimetry (DPIV) and refractive index matching (RIM) technique. A 3-D reacting flow model, which will be verified by DPIV flow data and single cell testing data, will be developed to simulate complex transport phenomena in SOFC and evaluate the diffusion limitations in anode and cathode. This numerical model can be implemented in predicting the cell performance and thus further improvement of the concentration polarization for planar SOFC can be achieved. For test and simulation of the optimal operating condition, we will consider how to increase the fuel utilization rate, because the higher the fuel utilization rate is, the lower the cost of the SOFC system. Therefore, we will evaluate the optimal range of fuel Reynolds number using single cell test or numerical simulations to achieve the reasonably higher power density with economic fuel utilization. This proposal should be useful for increasing the longevity and reducing the cost of planar SOFC. ; 研究期間 9701 ~ 9712

創新加壓型固態氧化物燃料電池設計測試及模擬分析; Experimental and Numerical Simulations of Innovative Pressurized-Assembling Designs for Planar Solid Oxide Fuel Cell

title: 創新加壓型固態氧化物燃料電池設計測試及模擬分析; Experimental and Numerical Simulations of Innovative Pressurized-Assembling Designs for Planar Solid Oxide Fuel Cell abstract: 本計畫針對兩大主題進行實驗測量和數值分析研究：(1)研發創新加壓型固態氧化物燃料電池(SOFC)的組裝技術和(2)測試流道尺寸效應對單電池堆性能之影響。前者工作項目有三：(1)針對壓力效應對電池性能之影響、加壓型SOFC組裝設計以及不同密封材料與技術於加壓型SOFC之適用性等三個議題作分析與彙整，並提出一完整的文獻回顧報告；(2)嚐試建立氣體洩漏率之測試平台，測試不同的密封材料或組裝技術於高溫高壓條件下之洩漏率，初期以溫度範圍(400 oC ~ 900 oC)和壓力範圍(1 atm~ 3 atm)為目標，逐步提升壓力範圍至約5 atm；(3)建立三維反應流場數值模式，並預測壓力效應對多孔電極內部的傳輸機制以及電池性能的影響。後者為流道尺寸效應與電池性能之研究，我們將以陶瓷材料(B85)或不鏽鋼材料(crofer-22-APU)，製作具有不同流道尺寸之棋盤狀流場板，並將其與電池基板組裝成單電池堆，以進行一系列的電池性能測試與阻抗頻譜量測。本計畫考慮單電池堆的性能測試需耗費許多經費，故我們將以數值模擬，進行流道尺寸對電池性能影響的靈敏度測試，希能找到適當的流道與棋盤狀凸出物面積比之電池性能優化設計，以減少實驗所需測試之次數，預期本計畫所獲得之成果，將有助於核研所未來開發加壓型金屬支撐SOFC之組裝設計。 This proposal focuses on two topics using both experimental measurements and numerical simulations: (1) Studying innovative pressurized-assembling technology for planar solid oxide full cells (SOFC) and (2) measuring the scaling effects of flow channels to cell performance of a single-cell stack. The former has three working items: (1) A survey of available literatures concerning the pressure effect to cell performance of planar SOFC, the assembling designs of pressurized SOFCs, and the suitability assessment of different sealing materials applying to pressurized SOFC; (2) attempting to establish a platform for the gas leakage testing, so that different assembling designs using various sealing materials can be tested at high-temperature and high-pressure conditions (400 oC ~ 900 oC; 1 atm ~ 3 atm and gradually increasing up to 5 atm); (3) establishing 3-D reacting flow models for predicting the pressure effects on cell performance. The latter, the scaling effects of flow channels to cell performance, is to use the ceramic material (B85) or the stainless steel (crofer-22-APU) for making different sizes of pin-type flow interconnects. Then these interconnects are assembled with the PEN to from a single-cell stack for a series of testing and measurements using the AC impedance instrument. Since the cost of the rig test using the single-cell stack is high, numerical simulations are applied for sensitivity analyses in attempt to find the optimal design of pin-type flow channel and to reduce the number of real tests. These results should be useful in due course for pressurized metal-support SOFC assembling technologies currently developing in INER. 研究期間：9901 ~ 9912

最佳化固態氧化物燃料電池堆設計測試及模擬分析; Simulation and analysis of planar SOFC for optimization

title: 最佳化固態氧化物燃料電池堆設計測試及模擬分析; Simulation and analysis of planar SOFC for optimization abstract: 本計畫延續上一年度之研究工作，分別利用實驗與數值模擬方法，深入探討三大主題：(1)電池堆優化設計、(2) SOFC多孔介質流道流場模擬分析和(3)不同流道設計單電池之電池性能實作測試和分析，分別敘述如下。(1)電池堆優化設計：將改良已有之實驗水力平台，並擴展其操作條件，進而測試不同的多層電池堆設計，並使流道雷諾數可操作於Re = 1 ~ 500的範圍。此外，將建立三維電池電化學數值模式，研究電池堆流場均勻度對電池性能之影響。(2) SOFC多孔介質流道流場模擬與分析：擬建立不同類型的多孔介質流場模擬設備，並使用折射率契合技術與質點影像測速儀，來進行多孔介質內之速度場量測。我們除了研究孔隙率與雷諾數因素對多孔介質內部動量傳輸之影響，並將利用由質點影像測速技術所獲得的實驗數據，來提供SOFC三維電化學數值模式中計算多孔介質表面和內部傳輸現象所需之邊界條件。(3)單電池性能測試：將首次以實際電化學實驗方法，研究流場均勻度對電池性能的影響。我們將針對不同流場設計之單電池，進行一系列的性能測試，量測電流-電壓曲線、電化學阻抗頻譜以及燃料使用率等重要的電池性能參數，並將使用掃描式電子顯微鏡以及X光粉末繞射儀，來分析SOFC電極微結構之變化，進而建立診測電池劣化機制之分析知識。本計畫將全力配合核研所正開發中之SOFC研究，著重於建立基礎學理電池性能劣化分析與電池元件優化設計等知識，期能對我國正推動之新能源技術，即SOFC發電系統計畫，所需之學理機制，有所貢獻。 This is a second-year proposal focusing on three topics: (1) Optimal design of cell-stack for uniform flow distribution, (2) modeling and analysis of flow distributions in porous electrodes of SOFC, and (3) single cell performance test and analysis using different flow designs. For the first topic, an already established hydraulic platform will be continuously modified to extend its operating conditions, so that, velocity distributions in different modules of multi-cell stacks over a wide range of flow-channel Reynolds number (Re) from 1 to 500 can be achieved. Furthermore, a three-dimensional, cell electrochemical model will be developed to investigate effects of flow uniformity in the cell-stack to the cell performance. Concerning the second topic, different types of porous flows will be established and the velocity distributions in these porous flows are measured using the particle image velocimetry together with the refractive index matching technique. Not only the effects of porosity and Re on the momentum transport in porous electrodes of SOFC will be evaluated, but also the correct boundary conditions at the porous interface to be used in 3D numerical model for SOFC will be obtained from experimental velocity data. For the third topic, the effect of flow uniformity on cell performance will be investigated experimentally using a single cell in a real testing platform for the first time. A series of single-cell testing experiments with different flow distributors will be carried out to obtain the important information of cell performance, such as the current-voltage curves, the electrochemical impedance spectroscopy, and the fuel utilization rate. Moreover, both the scanning electron microscope (SEM) and the X-ray diffraction (XRD) will be used to detect the failure of the electrodes. The obtained data are essential for diagnosing the degradation mechanisms for SOFC. This proposal aims to provide fundamental knowledge of the optimal cell design and mechanism of the cell degradation that are of help to the SOFC program currently developed by the Institute of Nuclear Energy Research (INER) 研究期間 : 9801 ~ 9812