Effects of operating parameters and loading mode on cell performance of PEM fuel cell stack

Autor: Hong-Ming Wang, 汪鴻銘
Rok vydání: 2009
Druh dokumentu: 學位論文 ; thesis
Popis: 98
Many single cells have to be connected in series in order to increase power. Such a collection of single cells in series is known as a stack. In this thesis, the main focus is to fabricate a stack of PEM fuel cell. The effects of operating conditions (including the stoichiometric ratio, cell temperature, inlet humidifying temperature) on stack performance of PEM fuel cell under various loading modes and dynamic loadings are also examined. A 4-cells stack is used to measure the current density and power density. The stoichiometric modes with values of 1.2/4, 1.2/3.5, 1.2/3, 1.2/2.5 and 1.2/2 are investgated. The results indicate the stoichiometric mode with values of 1.2/4 have a better stack performance. This is due to fully utilize the fuel of reactant. The cell temperutres are set as 65℃, 50℃, 40℃ and 30℃, repectively. The results show the best stack performance is noted for the case with 65℃ cell temperture. The inlet humidifying temperatures are 75℃, 70℃, 65℃, 50℃ and 40℃, repectively. It is found that the inlet humidifying temperature of 75℃ can obtain best stack performance. Addationally, the focus is to examine the variations of the dynamic characteristics of a stack under different loading modes. The effects of the stoichiometric ratio on the dynamic loadings are presented. The results show a lower stoichiometric ratio has a better stability. The each single cell stability increases with an increase stoichiometric ratio. As for the effects of the cell temperutre, the results reveal a lower stack temperure has a better stability. The each single cell for cell temperture of 65℃ has optimal stability. Finally, the experiment results show that both of the stack and single cell for the inlet humidifying temperature of 75℃ can obtain a better stability.
Databáze: Networked Digital Library of Theses & Dissertations
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