超輕型質子交換膜燃料電池之研究

Abstract

近年來在石油的波動當中，燃料電池興起是全球開發的重點。尤其以質子交換膜燃料電池系統將是未來主要電力來源，此系統運用包括了飛行器、家庭用電、農漁業、汽機車、船舶、潛艇、自行車及可攜式之電力系統。 為了改善傳統質子交換膜燃料電池系統之重量、成本及整合性的問題，本研究重點係以其主要元件(1)雙極板輕質化備製為主，其次是(2)儲氫氣瓶的輕量化設計，然後是(3)膜電極的穩定製程，最後研究(4)儲電元件之材料技術改進。 傳統雙極板的重量是佔電池組約90%，本研究將塑料(Polymethylmethacrylate, PMMA)以射出成型方法製成流場板，再利用塑料表面金屬化鍍層之研究，探討附著力、抗腐蝕、導電性及解決金屬層龜裂現象。在輕量化氫氣瓶的研發製作上則選用鋁合金材料 (7075-T6)以找出最佳銲接製程參數。膜電極(MEA)穩定製程的研究則以研發觸媒在電極上穩定之塗佈技術。儲電元件將以鋰鐵磷氧化物之煅燒技術製作。 本研究流程以田口實驗分析、CAE模流分析及多重偶合物理量分析為理論探討，並導入實驗設計之依據，由實體成品加工後，所得之實驗數據再與理論分析比較。實驗方法包括金相組織分析、電子顯微鏡觀察、原子力顯微儀觀察、物理性質及化學性質的量測。 由實驗結果得知，(1)射出模具之建立，以CAE模擬有助於模具開發，減少重修模具成本；在表面改質方面，機械粗化製程有較佳的附著力(均大於50 N)，在80℃以上的溫度有更好附著力，此溫度並適合在質子交換膜燃料電池系統上之工作溫度；(2)質輕的鋁合金儲氫氣瓶以電極間隙1.5mm、電流130A、速度200mm/min及保護氣體15L/min為最佳銲接數據，經由SGS水壓測試可達20Kg/cm2；(3)新設計的刮塗方式可有效的改善電極之電流穩定度；(4)以熱力學及流體力學之理論基礎，突破了傳統煅燒過程，製作出低成本的鋰鐵磷氧正極材料。因此本研究突破性的發展，對於研發者、工程師及工業界均有重要的貢獻。

Due to the oil shortage in recent years, the proton exchange membrane fuel cell (PEMFC) system becomes the main source of power in the future. This power system can be used in aircraft, household electricity, agriculture, fishing, motor vehicles, ships, submarines, bicycles and other portable power systems. To solve several existed problems for this PEMFC system such as weight, cost, and integration problems, this study emphasized on the manufacturing of lightweight bipolar plates, design of hydrogen-storage bottle made of aluminum alloy, the stability of manufacturing process of catalyst coating of membrane electrode assembly (MEA), and finally the improvement of manufacturing of materials used for the electricity-stored components. Since the weight of the traditional bipolar plates account for about 90% of the battery pack, an injection molding flow field plate made of polymethylmethacrylate (PMMA), with a metal-based surface coating, was developed. The adhesion, corrosion resistance, electrical conductivity, and cracking phenomenon of this metal-coated layer were examined. In the development of light-weight bottle for hydrogen storage, Taguchi method was used to determine the optimum process parameters of aluminum alloy (7075-T6) welding. The function and stability of MEA were studied mainly on the new-designed manufacturing process of electrode-catalyst coating technique. A new sintering technology was developed to produce lithium-iron-phosphorus oxide used as component of rechargeable batteries. CAE mold flow analysis and FEMLAB analysis were used for the simulation of the experimental design based on finished products. Experimental analysis included metallographic examination, SEM and AFM observation, and several physical and chemical properties analysis. The results indicate that the establishment of the injection mold of CAE simulation can help mold development and reduce the cost. Mechanical coarsening on the surface of PMMA can obtain a better adhesion (all greater than 50 N), in the temperature above 80 ℃, which is suitable for PEMFC system. Hydrogen storage bottle of aluminum alloy can be manufactured by proper welding parameters. New scrape-applied method was developed to improve the electric current stability of the electrode. Finally, new sintering technology based on thermodynamics and fluid mechanics was developed and tested successfully.