Abstract:

The gradient distribution of platinum loading in the catalyst layer along the flow channel direction affects the utilization of reactants and the transfer of heat and species. On this basis, the influence of operating conditions on the cell performance, heat and mass transfer of proton exchange membrane fuel cells with platinum loading gradient distribution along the flow channel direction is still unclear. Therefore, based on a two-dimensional, non-isothermal, two-phase proton exchange membrane fuel cell model, the effects of reactants flow direction and stoichiometric ratio on proton exchange membrane fuel cells with the two-gradient distribution or the three-gradient distribution of platinum loading in the multi-gradient distributions were investigated. The results show that the reactant flow direction has a weak impact on the electrical performance and species content of platinum loading gradient distribution fuel cells and the increase of stoichiometric ratio can improve the performance of the fuel cell with platinum loading gradient distribution. Furthermore, with the increase of stoichiometric ratio, the performance improvement degree of the cell with gradient distribution of platinum loading increases compared with the uniform distribution.

Key words: proton exchange membrane fuel cell, catalyst, non-uniform distribution, operating condition, cell performance, heat transfer, mass transfer

摘要：

催化层中铂载量沿流道方向的梯度分布会影响反应物利用以及热量和物质的传递，而操作条件对铂载量梯度分布质子交换膜燃料电池电性能和传热传质的影响尚不明确。因此，基于二维、非等温、两相质子交换膜燃料电池模型探究了操作条件反应物流向和化学计量比对铂载量二梯度分布和多梯度分布中的三梯度分布质子交换膜燃料电池的影响。研究表明，反应物流向对铂载量梯度分布燃料电池的电性能和物质含量的影响较弱；化学计量比的增加可以提高铂载量梯度分布燃料电池的电性能，并且随着化学计量比的增加，铂载量梯度分布的燃料电池性能相对于均匀分布的燃料电池性能的提升效果增强。

关键词: 质子交换膜燃料电池, 催化剂, 非均匀分布, 操作条件, 电池性能, 传热, 传质