Understanding mechanical performance evolution and failure mechanism of solid oxide fuel cell stack (SOFCs) during long-term operation period are essential to prolong operation life and advance commercialization. In this study, based on the structural mechanical model, the evolution characteristics of thermal stress, failure probability, strains, and deformation of SOFCs fueled by partially pre-reformed CH during 3000 h' operation are revealed. It's found the maximum thermal stresses of anodes, sealants, and frames/ICs decease respectively by 82.9%, 74.1%, and 88.4%, while those of electrolytes and cathodes firstly fluctuate then increase. The failure probabilities of sealant and anode decrease by 6∼10 orders of magnitude, while increase by 1 order of magnitude and 1.5 times for electrolyte and cathode. 300 h later, sealant may fracture by creep strain, while the component most likely to fail due to thermal stress changes from sealant to cathode. The maximum deformation of positive electrode-electrolyte-negative electrode (PEN) locates in anode of cell 15. It is suggested creep resistance of sealant be improved to avoid creep fracture, mechanical strength of cathode/sealant be increased to decrease failure probability, and the temperature unevenness be decreased to avoid larger deformation.

中文翻译：

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15 节固体氧化物燃料电池堆的长期热机械性能演变

了解固体氧化物燃料电池堆（SOFC）在长期运行期间的机械性能演变和失效机制对于延长运行寿命和推进商业化至关重要。在这项研究中，基于结构力学模型，揭示了部分预重整CH为燃料的SOFC在3000小时运行期间的热应力、失效概率、应变和变形的演化特征。发现阳极、密封胶和框架/IC的最大热应力分别下降了82.9%、74.1%和88.4%，而电解质和阴极的最大热应力先波动后增加。密封胶和阳极的失效概率降低了6~10个数量级，而电解质和阴极则增加了1个数量级和1.5倍。 300小时后，密封剂可能会因蠕变应变而断裂，而组件最有可能因密封剂到阴极的热应力变化而失效。正极-电解液-负极(PEN)的最大变形位于电池15的阳极。建议提高密封胶的抗蠕变性以避免蠕变断裂，增加正极/密封胶的机械强度以降低失效概率，并提高密封胶的机械强度以降低失效概率。减少温度不均匀性，避免产生较大的变形。