以步階電壓負載測試法分析直接甲醇燃料電池之研究

A Study of Analyzing Direct Methanol Fuel Cells by Step Voltage Load Test

黃士益(Shih-I Huang)

指導教授 ： 蘇春熺

國立臺北科技大學/機電學院/機電整合研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00518

摘要

近年來由於石油價格上漲，伴隨著電費也跟著上漲，各個電子產品逐漸設計偏向有待機省電的模式，當電子產品由待機模式開啟進入一般模式時，此時電壓與電流的需求會瞬間上升。由於直接甲醇燃料電池可達到輕薄短小之要求，成為電子產品電源最佳的選擇。本研究為了測試直接甲醇燃料電池在負載瞬間提升和下降時是否能夠及時提供足夠的電壓與電流，利用燃料電池平台將電壓負載瞬間提升與瞬間下降，並紀錄電池之電壓變化情形；另外，本研究利用步階電壓負載測試法來對直接甲醇燃料電池進行等效電路阻抗分析，配合MATLAB計算出等效電路中之阻抗值。由實驗之結果得知，燃料電池在一定範圍內的電壓瞬間上升是可以立即反應的，然而超過此一範圍則需要一段時間後才會達到所要求之電壓負載，所以直接甲醇燃料電池(DMFC)是可以應用在這些類型的電子產品上面。在電壓負載上升超過某一範圍後，由燃料電池之電壓反應可觀察到有電容充電的現象，利用這些電壓反應進行等效電路阻抗分析，可計算出等效電路中各阻抗之阻抗值。以25 ℃、3 %甲醇測試所得到的阻抗值，Rohm=0.9947 Ω，Rct=0.9530 Ω，Rmt=1.1513 Ω；以25 ℃、7 %甲醇測試所得到的阻抗值，Rohm=1.0917 Ω，Rct=0.5822 Ω，Rmt=1.3738 Ω，比較不同濃度之阻抗值，甲醇濃度越高Rohm之阻抗值越高，Rct之阻抗隨甲醇濃度增加而降低，Rmt之阻抗則隨甲醇濃度增加而增加。故步階電壓負載測試法可替代交流阻抗來檢測阻抗值，可以得到不錯的結果，但是要測試不同電流下之阻抗值，還是要以交流阻抗測試來分析。

關鍵字

直接甲醇燃料電池 ； 等效電路 ； 燃料電池測試平台

並列摘要

According to the prices of oil and the power bill keep going up, some electronic products change their mode to keep energy when they are not working. When they start working and change to general mode, the need of voltage and current will increase in a short time. Direct methanol fuel cell has some advantage, so it can be some electronic product's power. This study test direct methanol fuel cell by increasing the voltage load in a short time to test whether direct methanol fuel cell can provide enough voltage or not. In this study, by using step voltage load test to analyze the impedance of DMFC, and calculated the resistance in equivalent circuit by MATLAB. This study use fuel cell test station to test fuel cell, and to take down the voltage response. According to the result, DMFC can reach the voltage load in a small range quickly, but out of this range DMFC have to take much time to reach the voltage load. As this result, direct methanol fuel cell can setup on those products. When the voltage load out of the range, the voltage response can be observed that there are capacity charge reaction, and using those reaction to analyze the impedance of DMFC. The result of resistance at 25 ℃ and 3 % methanol is Rohm=0.9947 Ω, Rct=0.9530 Ω, and Rmt=1.1513 Ω. The result of resistance at 25 ℃ and 3 % methanol is Rohm=1.0917 Ω, Rct=0.5822 Ω, and Rmt=1.3738 Ω. It can calculate the value of resistance in equivalent circuit, so step voltage load test can displace AC-impedance to calculate the value of resistances and get good results. But, getting the resistance in different current, it has to use AC-impedance.

並列關鍵字

Direct Methanol Fuel Cell (DMFC) ； Equivalent Circuit ； Fuel Cell Test Station

參考文獻

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