Influence of rib spacing in proton-exchange membrane electrode assemblies
Influence of rib spacing in proton-exchange membrane electrode assemblies
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DOI：
10.1007/bf00253453
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发表时间：
1996-06
影响因子：
2.9
通讯作者：
A. West;T. Fuller
中科院分区：
文献类型：
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作者：
A. West;T. Fuller
对质子交换膜燃料电池的膜电极组件进行了二维设计分析。具体地说，双极板的肋条限制燃料和氧化性气体进入催化层。通过对氧电极和膜分离器的数值模拟，研究了基板层部分堵塞对电池性能的预期影响。给出了肋骨尺寸和气体扩散电极厚度对电池内电流和水分布的影响。对于所考虑的所有情况，对于给定的外加电流，二维效应对半电池电位的影响很小，但对水管理有很大的影响。在膜电解液中使用具有可变传输性质的集中溶液理论来求解电位和局部含水量。气体扩散电极采用Stefan-Maxwell方程确定氮气、氧气和水蒸气的局部摩尔分数，采用控制体积法求解耦合的非线性微分方程组。与有限差分法相比，控制体积法的一个优点是在处理燃料电池和电池模型中的内部边界点时相对容易。简要讨论了这一优点和其他优点。
A two-dimensional design analysis of a membrane-electrode assembly for a proton-exchange membrane fuel cell is presented. Specifically, the ribs of the bipolar plates restrict the access of fuel and oxidant gases to the catalyst layer. The expected change in cell performance that results from the partial blocking of the substrate layer is studied by numerical simulation of the oxygen electrode and the membrane separator. The effects of rib sizing and the thickness of the gas-diffusion electrode on the current and water distributions within the cell are presented. For all of the cases considered, the two-dimensional effect only slightly alters the half-cell potential for a given applied current but has a significant influence on water management.Concentrated solution theory with variable transport properties is used in the membrane electrolyte to solve for the electrical potential and local water content. The Stefan-Maxwell equations are used in the gas-diffusion electrode to determine the local mole fractions of nitrogen, oxygen and water vapour.A control-volume formulation is used for the resolution of the coupled nonlinear differential equations. One advantage of the control-volume approach over finite-difference methods is the relative ease in which internal boundary points in fuel-cell and battery models are handled. This and other advantages are briefly discussed.