摘要 |
A fuel cell unit of a proton exchange membrane fuel cell system includes a pair of flow field plates and a membrane electrode assembly. The membrane electrode assembly is interposed between the pair of flow field plates to define respective reactant flow channels with the pair of flow field plates. The membrane electrode assembly includes an anode catalyst layer, a cathode catalyst layer, a proton exchange membrane and a pair of gas diffusion layers. The gas diffusion layers are respectively disposed adjacent to the anode catalyst layer and the cathode catalyst layer and face to the flow field plates. At least one of the gas diffusion layers has a fluid permeability distribution profile increasing first and then decreasing from an inlet to an outlet of the reactant flow channel. The gas diffusion layer has the maximum fluid permeability at the site with the highest rate of reaction.
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