Electrical and thermal contact resistance of porous fuel cell electrodes

梅赛德斯-奔驰加拿大-燃料电池事业部(MBC)致力于为零排放道路车辆生产聚合物电解质膜燃料电池(PEMFC)电堆。PEMFC电堆的运行关键依赖于膜电极组件(MEA)，膜电极组件是电池核心的多层组件，促进了几个传输过程和产生电能的电化学能量转换。多孔MEA层之间的界面对运输过程的有效性有重大影响，进而影响汽车燃料电池堆的性能、可靠性和耐用性。这项研究建立在先前的Engage项目的基础上，以确定电气和热接触电阻。这项研究集中在MEA的两个特定组分之间的界面：催化层和微孔层。该方法包括(I)利用激光扫描显微镜表征多孔燃料电池材料的表面粗糙度和形貌；(Ii)计算重建接触的多孔介质；(Iii)接触界面的接触力学模型；以及(Iii)使用孔尺度模拟来预测有效的界面传输特性。这项研究将有助于量化制造和装配公差对多边环境协定生产中界面传输的影响这一长期目标。这项研究将能够确定作为压缩压力函数的电性和热性接触电阻；并检查缺陷(如孔洞和裂缝)的影响。

Mercedes-Benz Canada-Fuel Cell Division (MBC) is engaged in the production of polymer electrolyte membrane fuel cell (PEMFC) stacks for zero emission road vehicles. The operation of PEMFC stacks depends critically on the membrane-electrode assembly (MEA), a multilayered component at the core of a cell that facilitates several transport processes and the electrochemical energy conversion that generates electrical power. The interfaces between the porous MEA layers have a significant impact on the effectiveness of the transport processes and, in turn, on the performance, reliability and durability of an automotive fuel cell stack. This research builds on a previous Engage project to determine electrical and thermal contact resistance. The study focuses on the interface between two specific components of the MEA: the catalyst layer and the micro-porous layer. The methodology involves (i) characterization of the surface roughness and morphology of the porous fuel cell materials using laser scanning microscopy; (ii) computational reconstruction of the contacting porous media; (iii) contact mechanics modelling of the interface; and (iii) prediction of effective interfacial transport properties using pore-scale simulations. This research will contribute toward the long term goals of quantifying the impact of manufacturing and assembly tolerances on interfacial transport in production MEAs. The study will allow determination of electrical and thermal contact resistance as a function of compressive pressure; and examination of the impact of defects such as holes and cracks.