| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 97 === Metal foam is used in this study to replace the traditional graphite flow field plate. Along with commercial catalyst coated membranes, single and multi-cell fuel cell stacks are assembled to investigate the effects of the reactant flow rate, operation temperature, and humidification temperature on the cell performance.
Metals have good electrical conductance and mechanical strength, which are suitable for bipolar plates in fuel cell stacks. Previous studies have shown that fuel cells using metal foam to replace traditional flow channels can have very good performance. The purpose of this study is to study the operation performance and characteristic of the fuel cell stack. In addition, the long-term performance and AC impedance are also investigated in this study.
The results show that the performance of the fuel cell stack is improved by increasing the air flow rate. If oxygen is used as the oxidant, the required flow rate is lower. In order to get better cell performance, suitable humidification in the reactant is required. For long-term operation, periodic purging in the cathode can reduce the polarization loss due to mass transfer.
Equivalent circuit model of the fuel cell stack system can be built from the AC impedance analysis. The results show that the main resistance in this system is mass transfer resistance.
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