直接液体甲醇燃料电池流场组织行为研究(Ⅰ) 传统对称流道电池的模型建立

STUDY ON THE CHARACTERISTICS OF FLOWING ORGANIZATION IN DMFC PartⅠ:Model Development of Cell with Conventional Symmetrical Plates

建立了直接甲醇燃料电池垂直流道方向电池单元的二维稳态数学模型,考虑了电化学动力学、多组分传递和甲醇渗透影响。计算了流道布置密度、扩散层、催化层和质子交换膜等组件尺度对电池内物料传质特性、化学反应组织和电池输出性能的影响。研究发现,增加流道布置密度、增加催化层厚度能有效提高电极反应均匀性和电池性能。其中催化层和质子膜的厚度影响最为显著,在该文研究范围内分别可提高电池的平均电流密度131.0%和17. 8%。而扩散层和质子交换膜厚度都存在一个最佳值,需要与以上流场板设计尺寸和膜电极尺寸匹配。

A two-dimensional, steady-state model of a direct methanol fuel cell （DMFC） with liquid methanol feed was developed. The electrode kinetics, multi-component transport and methanol crossover phenomenon were all considered. The effect of channels disposal density, the influence of backing layer, catalyst layer and polymer electrolyte membrane thickness on mass transfer and cell performance was investigated. The results showed that： with the increase of channels disposal density and the increase of catalyst layer thickness, the equality of reaction rate and cell performance will elevated. The sizes of catalyst layer and membrane effect farthest, the correspondingly optimized work can increase the average current density about 131.0% and 17.8%. There are moderate optimal thickness sizes of backing layer and membrane, and the sizes should be chosen after thinking about the sizes of flow field plate and MEA.