Effect of porosity distribution on performance of proton exchange membrane fuel cells
The three-dimensional models of proton exchange membrane fuel cell(PEMFC)with parallel,serpentine and leaf vein flow fields were established,and the oxygen distribution characteristics of catalytic layer(CL)in different models were analyzed.The corresponding porosity gradient distribution schemes in gas diffusion layer(GDL)were proposed for different flow models.The oxygen molar fraction distribution,membrane current density distribution,polarization curve and power density curve in different flow field models were analyzed.Results show that the proposed porosity gradient distribution scheme can effectively enhance the oxygen transfer from GDL to CL,improve the local oxygen supply deficiency of CL,and enhance the output performance of PEMFC.Compared with the parallel,serpentine and leaf vein flow field models of the conventional porosity distribution,the peak power density of the flow field model using the porosity gradient distribution increased by 8.59％,18.26％and 15.46％,respectively.
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