| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 97 === 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.
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