漸縮/漸擴元件應用於壓電式質子交換膜燃料電池之研究

Abstract

由過去之研究得知，將漸縮/漸擴元件應用於質子交換膜燃料電池之陰極端，能解決積水問題，提升燃料電池之性能表現。本文將探討漸縮/漸擴元件在不同展弦比(AR)與開口角度(θ)下對壓電式質子交換膜燃料電池性能之影響。並且以單電池為基礎設計出有類雙極板結構之壓電式質子交換膜燃料電池雙電池組，此設計中電池反應面積為2mm*2mm，兩個電池以陰極對陰極，陽極則分別位於最外兩側之並聯方式連接，兩個電池的陰極端共用一壓電元件以吸入並排出陰極腔體中之流體。實驗結果發現當漸縮/漸擴元件開口角度10°與展弦比5.63時有較好之性能表現，角度太大時，在一個週期內分離流產生時間較長；而展弦比太大時，在漸擴元件中會發生阻塞現象，使得進入陰極腔體的空氣流量減少。研究也顯示此新式漸縮/漸擴壓電式質子交換膜燃料電池雙電池組在開口角度10°與展弦比5.63時能輸出之最大功率密度為0.27W/cm2，且此雙電池組在壓電頻率60Hz時，能有0.84W的淨輸出功。

Previous studies of piezoelectric proton exchange membrane fuel cell with nozzle and diffuser (PZT-PEMFC-ND) have shown that a PZT device could solve flooding problems and improve cell performance. In this study, we discuss the performance of PZT-PEMFC-ND with different nozzle and diffuser geometry design. And a PZT-PEMFC-ND bi-cell with pseudo bipolar electrodes was developed to achieve a higher power output. This new design, with a reaction area of 4cm2, contains two cells with two outside anodes and two inside cathodes that share a common PZT vibrating device for pumping air flow. The experiment results show that a proper open angle of 10° and a proper aspect ratio(AR) of 5.63 could have a better cell performance. A larger open angle value will cause longer time of separation in one period. A larger AR of 11.25 and 16.88 induced a blocking phenomenon inside the diffuser element, and thus less air was sucked into the cathode chamber. This study also concludes that the innovative design of the PZT-PEMFC-ND bi-cell could reach the best performance of 0.27W/cm2 at the condition of AR5.63 and θ=10°. And the bi-cell can have a net power output of 0.84W at 60Hz.