石墨及PDMS呼吸式質子交換膜燃料電池之水管理與熱分佈分析

Abstract

本文主要為研究以PDMS與石墨質子交換膜燃料電池之實驗測試，探討反應面積為5公分×5公分的單電池。第一部分是PDMS(聚二甲基矽氧烷)單電池之研究，實驗參數包括流量及其對應之氫氣利用率以及組裝時鎖合扭力的影響；第二部分是石墨單電池的研究，實驗參數包括流量、鎖合扭力以及電池溫度的影響，此兩部分實驗皆用熱顯像儀拍攝陰極溫度分佈；另外，PDMS與石墨燃料電池都經由長時間24小時放電測試以觀察其耐久度。最後，本論文將PDMS與石墨燃料電池做性能的比較與分析。 由實驗結果可知，PDMS與石墨燃料電池的性能都隨著流量的增大而增大，但PDMS燃料電池到達60sccm和石墨燃料電池到達40sccm以上，性能就不會再增大；PDMS燃料電池的氫氣利用量是60sccm，因此熱顯像儀拍攝出的溫度分布在此流量時較均勻；電池組裝之鎖合扭力必須在不使流道結構變型的情況下增加才能有效提升其性能；石墨燃料電池的性能會隨著電池溫度的增加而增加，到達60℃以上，性能會隨著溫度的增加而減少；PDMS燃料電池堆經過二十四小時長時間測試後，都有良好的耐久度，但是石墨的卻不穩定，但若將石墨電池溫度加熱至60℃，即有穩定的輸出；經比較後，在同樣的條件下和同樣的阻抗下，PDMS燃料電池皆比石墨燃料電池性能表現佳；由於PDMS燃料電池有比較少的積水現象，因此比石墨燃料電池更適合用在呼吸式燃料電池上。

This study fabricated PDMS (Polydimethyl Siloxane) and graphite PEMFC (Proton Exchange Membrane Fuel Cell). The active area of the membrane is 5cm×5cm. Firstly, a series of performance experiments on a single PDMS air-breathing PEMFC were carried out and demonstrated. The experimental parameters included flow rate with the corresponding hydrogen utilization and clamping force. Secondly, the similar performance experiments on single graphite air-breathing PEMFC were also carried out and illustrated. The experimental parameters consisted of flow rate, clamping force and cell temperature. For both experimental studies, the corresponding thermal imagines of resultant temperature distributions on the cathode surface were given as well. In addition, in order to justify the durability of continuous usage and water produced situation, both fuel cells mentioned above were tested for 24 hours at a fixed operating voltage. Finally, we made a comparison between PDMS and graphite PEMFCs to see the performance difference and the advantage. The experimental results show that both the performances of the single PDMS and graphite air-breathing PEMFC increase with an increase of flow rate, but have no further obvious improvements when the flow rates are greater than 60sccm and 40sccm, receptivity. The hydrogen utilization of the single PDMS PEMFC is 60sccm, and the corresponding thermal image show its temperature distribution being more uniform; An appropriate clamping torque should be considered carefully to enhance the performance without narrowing the fuel flow channels; The performance has significantly improved as increasing graphite fuel cell temperature, however, it starts to decrease as the cell temperature above 60℃; The single PDMS fuel cell can maintain a stable power output for a long time use up to 24 hours. One the contrary, the single graphite air-breathing PEMFC cannot, but it can maintain a stable power output when the cell temperature is raised to 60℃ manually; The PDMS PEMFC has a better performance than that of the graphite one under the same conditions and the same resistance; PDMS is a better material than graphite for air-breathing fuel cell because it has less water flooding effects and possesses a better performance.