The achievement of durability targets is an important challenge for the commercialization of fuel cell electric vehicles (FCEV). In order to meet the requirements, knowledge about the most severe degradation mechanisms of fuel cell stacks under automotive conditions is crucial. In the present work, degradation analysis of an automotive full size stack is performed. Herein, we focus on defects at the cathode catalyst layer and their interrelation including inhomogeneous adhesion of the microporous layer on the catalyst layer, crack formation, cathode catalyst layer thinning and wrinkling of the catalyst coated membrane. In addition, we report linear and circular Pt depositions on top of the cathode catalyst layer, which have to the best of our knowledge not been described in literature yet. For the latter, a degradation mechanism based on liquid water formation, local fuel starvation and current density distribution at the interface between microporous layer and cathode catalyst layer is postulated. Finally, a fast indication for stack degradation is suggested by correlating different degradation phenomena. This improved stack analysis approach allowed us to detect local differences in degradation on both cell and stack level.

中文翻译：

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汽车PEMFC全尺寸烟囱的局部燃料不足降解

耐久性目标的实现是燃料电池电动汽车（FCEV）商业化的重要挑战。为了满足要求，关于在汽车条件下燃料电池堆最严重的降解机理的知识至关重要。在本工作中，对汽车全尺寸烟囱进行了降解分析。在此，我们集中于阴极催化剂层处的缺陷及其相互关系，包括微孔层在催化剂层上的不均匀粘附，裂纹的形成，阴极催化剂层的变薄和催化剂涂覆膜的起皱。此外，我们报告了在阴极催化剂层顶部的线性和圆形Pt沉积，据我们所知，文献中尚未对此进行描述。对于后者，提出了基于液态水形成，局部燃料不足和微孔层与阴极催化剂层之间界面处电流密度分布的降解机理。最后，通过关联不同的退化现象，提出了堆栈退化的快速指示。这种改进的堆栈分析方法使我们能够在电池和堆栈级别上检测出局部退化。