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）致力于生产用于零排放道路车辆的聚合物电解质膜燃料电池（PEMFC）电池组。PEMFC堆叠的运行主要取决于膜电极组件（MEA），这是电池核心的多层组件，可促进多种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产生重大影响，进而影响汽车燃料电池堆的性能、可靠性和耐用性。这项研究建立在之前的Engage项目的基础上，以确定电和热接触电阻。研究重点是MEA的两个特定组成部分：催化剂层和微孔层之间的界面。该方法包括(i)使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）接触多孔介质的计算重构；（iii）界面接触力学建模；(3)利用孔隙尺度模拟预测有效界面输运性质。这项研究将有助于量化制造和装配公差对生产环境环境中界面传输的影响的长期目标。该研究将允许确定电和热接触电阻作为压缩压力的函数；并检查孔洞、裂纹等缺陷的影响。

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.