鋅燃料電池電化學極化特性之研究

Study of Electrochemical Polarization Characteristics of Zinc Fuel Cell

羅文德(Wun-Der Luo)

指導教授 ： 黃國修

國立臺北科技大學/機電學院/車輛工程系所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00150

摘要

本研究主要探討鋅燃料電池電化學極化特性之參數管理。燃料電池雖然可藉由極化曲線提供電池性能之定量特性，以作為判斷燃料電池性能好壞的依據，但卻無法有效分辨出燃料電池內部各個損失大小，然而再搭配電化學交流阻抗分析法，透過阻抗的時間或頻率的變數，便可觀察鋅燃料電池的電化學反應機制，並分析電池在不同操作條件下各個內部電阻的影響程度，試著分析出電化學反應過程中的主導因子。
由實驗結果顯示，電池在小電流放電下，電阻行為主要是由極化電阻(Rp)為主導；當電池操作在中電流放電時，電阻則受電流的影響不大，此時電池主要歐姆阻抗(Rs)為主導；在高電流放電時，電池逐漸由質傳電阻(Rm)作為主導。而集電材質以純鎳效果最佳，鍍鎳則會縮短空氣電極使用效率。此外，給予電池適當的空氣流速可提供充足的空氣提升電池性能，但風速過大則會因壓差現象造成性能下降；其阻抗值再小電流狀態下，空氣流速影響不大，但隨著電流越大，質傳阻抗(Rm)影響逐漸增大，此時空氣流速的提昇使質傳電阻(Rm)有明顯改善。在量測溫度過程中，因高溫使電解液水分散失過快，導致電解液濃度( OH- )改變，再加上電解液( OH- )吸收二氧化碳使電池碳酸化增加，逐漸破壞電池造成電池極化加劇，使得溫度提高無法有效提升電池性能。最後將各項實驗參數調整後，單電池最大功率達到16.5W，對應之電壓為0.8V，功率最高點之電流密度約為430mA/cm2，相較先前電池，其電池性能提升約33%。

關鍵字

鋅燃料電池 ； 交流阻抗 ； 極化特性 ； 電化學

並列摘要

This study intends to discuss the parameter management of zinc fuel cell electrochemical polarization. Although the fuel cell polarization curve can be provided by the quantitative characteristics of cell performance, in order to determine as a basis for good or bad, but is unable to effectively distinguish the fuel cell interior various loss. However by EIS analysis, Impedance by time or frequency variable can be observe the zinc fuel cell electrochemical reaction mechanism, and analyzes the cell under the different operating condition each internal resistance influence, tries to analyze leading factor of the electrochemistry reaction process.
Demonstrated by the experimental result that the fuel cell under low current discharge, the resistant behavior mainly by the polarization resistance (Rp) oriented; When the cell is operating in the mid-current discharge, the cell driven mainly by the ohmic resistance (Rs); In the high current discharge, the cell gradually from the mass transfer resistance (Rm) as the lead. The collector material to best effect by the pure nickel, Because the nickel plating will reduce the air electrode use efficiency. In addition, proper air flow to the cell can provide sufficient air to improve cell performance, but the wind speed oversized the differential pressure phenomenon will cause the performance to drop; The air velocity has little effect in the impedance value at the small current state. However, when the current increases that mass transfer resistance become greater, at this time the air velocity increase can improve the mass transfer resistance. In the process of measuring temperature, electrolyte water loss due to high temperature, resulting in electrolyte concentration (OH-) change, and the electrolyte absorption carbon dioxide increase cause carbonated of the cell, causes the cell damage to the polarized aggravating, making the temperature increase can not effectively improve cell performance. After finally each experiment parameter adjustment, the single cell maximum power approximately 16.5W at the 0.8V, and the maximum power point of the current density of about 430mA/cm2. Compared with the previous cell, the cell performance increased by about 33%.

並列關鍵字

Zinc Fuel Cell ； EIS ； Polarization ； AC impedance

參考文獻

[6]G.M. Wu, S.J. Lin and C.C. Yang, "Alkaline Zn-air and Al-air cells based on novel solid PVA/PAA polymer electrolyte membranes," Journal of Membrane Science, vol.280, 2006, pp.802-808.

[8]S. I. Smedley, "A regenerative zinc–air fuel cell," Journal of power sources, vol.165, 2007, pp.897-904.

[10]D. Linden, Handbook of batteries and fuel cell: New York: McGraw-Hill, 1984.

[11]E. Brillas, F. Alcaide and P. L. Cabot, "A Small-Scale Flow Alkaline Fuel Cell For On-Site Production of Hydrogen Peroxide," Electrochimica Acta, vol.48, 2002, pp.331-340.

[12]Y. Wang and H. Zhou, "A lithium-air battery with a potential to continuously reduce O2 from air for delivering energy," Journal of Power Sources, vol.195, 2010, pp.358-361.