以微機電製程製作微型PDMS質子交換膜燃料電池之實驗研究

Abstract

本文主要為研究以微機電製程製作微型PDMS質子交換膜燃料電池之實驗測試。探討反應面積為2公分×2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，實驗參數包括集電片開孔形狀、對流方式、以及組裝時鎖合扭力的影響；第二部分是PDMS平板電池堆的研究，實驗參數包括鎖合扭力以及燃料供應方式的影響；另外，單電池及電池堆都經由長時間放電測試以觀察其耐久度。最後，本論文也將PDMS微型燃料電池與矽微型燃料電池做性能的比較與分析。 由實驗結果可知在相同開孔率之集電片下，不論陰極採用呼吸式或是強制對流式 (有流場板)之單電池，其性能皆隨集電片之開孔數增加而提升；強制對流方式的單電池比較適合高電流密度輸出使用，而呼吸式燃料電池較適合低電流長時間輸出使用；電池組裝之鎖合壓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；對於本實驗之電池堆設計，由於陰極端的空氣提供速率有限，因此增加燃料流量並無法有效改善濃度極化現象；另外，電池堆中之每顆單電池因為燃料供應順序不同而會有不同性能表現；單電池與電池堆經過十四小時長時間測試後，都有良好的耐久度；經比較後，不論陰極採用呼吸式或是強制對流式，PDMS基材之單電池皆比矽基材之單電池性能表現佳；由於PDMS基材有比較少的積水現象，因此比矽基材更適合用在呼吸式微型燃料電池上。

This study fabricated micro PDMS (Polydimethyl Siloxane) PEMFC (Proton Exchange Membrane Fuel Cell) by using the MEMS (Micro Electro Mechanical Systems) technology. The active area of the membrane is 2cm×2cm. Firstly, a series of performance experiments on a single micro PDMS PEMFC was carried out. The experimental parameters included current collector shape, convection type and clamping force, respectively. Secondly, a planar PEMFC stack was designed and assembled to test the performance. The experimental parameters consisted of clamping force and fuel supply condition. In addition, both the single cell and the stack were tested for durability. Finally, a comparison between PDMS-based PEMFC and silicon-based one was made. The experimental results show that both the performances of the air-breathing and forced convection cells increase with an increase of the circle numbers from one to twenty-five on the current collector under the same current collector open ratio; The forced convection cell is a better choice for long-time high current-density output whereas the air-breathing cell is more suitable for lower current density output; An appropriate clamping torque should be considered carefully to enhance the performance but without narrowing down the fuel flow channels; The increase of flow rate is not a best way to improve the concentration loss in this air-breathing stack experiment because of the limiting air supply, and each cell in the same stack has different performance under series arrangement; Both the single micro PDMS fuel cell and the cell stack can maintain a stable power output for a long time use up to 14 hours; The PDMS-based PEMFC has a better performance than that of the silicon-based one under both forced oxygen supply and the air-breathing ways; PDMS is a better material than silicon for micro air-breathing fuel cell because it is with less water flooding effects.