質子交換膜燃料電池內溫度分佈對其性能影響之分析

Abstract

本文之目的在探討質子交換膜燃料電池內溫度變化對其性能之影響。首先本研究建立了一維理論模式，溫度場方程式除了考慮質子交換膜內的電滲透現象，還考慮孔隙材質內氣體傳輸以及水蒸發或凝結所造成的熱影響。本文先探討當考慮溫度變化時對其性能影響，再進一步討論系統的操作溫度以及不同的陰陽極入口條件對燃料電池的各種影響。 燃料電池在操作時會因為本身的電化學反應所生成的熱以及通入的反應氣體溫度而使得電池內部的溫度呈現非均勻的現象，但過去的研究大都以等溫模式來分析電池的各種特性。但事實上，溫度的影響是的確存在的，所以本文先探討把溫度變化的參數加入模式裡來討論電池表現有何不同，結果顯示，若入口氣體的溫度一樣時，則電池內部的溫度變化不明顯，故對電池的影響不大。 在電池操作溫度變化對其性能的影響部份，結果顯示當電池的操作溫度上升時，電池的性能會下降，反之，當電池的操作溫度下降時，電池的性能會上升。若改變陰陽極入口溫度，則研究發現，當陽極入口溫度上升時，電池的性能會上揚，而陰極的入口溫度下降時，電池的性能會變好。

An analysis of the one-dimension non-isothermal mathematical model for a proton exchange membrane (PEM) fuel cell is adopted to investigate the effect of the temperature gradient on the performance of the proton exchange membrane fuel cell. The diffusion equation for the reactant gases through the porous media, and consider phase change of water with the saturated reactant streams in the gas diffuser layers, electro-osmotic drag of liquid water in the membrane by the proton migration, and the energy equation for the temperature profile across the PEM fuel cell is employed. The influence of the temperature gradient on the performance are been investigated. Besides, we studied the effects of the operating cell temperature and different anode and cathode inlet temperature on the performance. The results show that the temperature gradient in the cell is not large, even at high current density. The results indicate that when the cell temperature decreases, the cell performance will be better. If one of the inlet reactant gases (anode or cathode) temperature is constant and varies the other side inlet reactant gases temperature, the performance of the cell will be enhanced as the other side inlet reactant gases temperature decreasing. In particular, the performance will be much better when cathode inlet reactant gases temperature decreases.