Strength and energy conversion efficiency of thermoelectric (TE) thin films upon cyclic mechanical loading are major concerns for flexible thermoelectric generator (TEG) applications. A comprehensively analysis model for the performance evaluation and fatigue failure of a TEG is constructed in this paper. The analytical solutions of temperature field, stress field, fatigue life, power output and energy conversion efficiency of the flexible TEG under cyclic loading are presented. A bending experiment is carried out to validate the analytical model and to fitting the model parameters. The results show that a continuing increase of electrical resistance and decrease of power output under the cyclic bending. The electrical resistance and power output of the TEG varies with the bending radius. The thickness ratio of the substrate to the TE film has a great influence on power output and energy conversion efficiency. A critical bending radius can be obtained from the model to provide a guideline for future flexible TEG design.

热电 (TE) 薄膜在循环机械载荷下的强度和能量转换效率是柔性热电发电机 (TEG) 应用的主要关注点。本文构建了一种用于TEG性能评估和疲劳失效的综合分析模型。给出了柔性TEG在循环载荷下的温度场、应力场、疲劳寿命、功率输出和能量转换效率的解析解。进行弯曲实验以验证分析模型并拟合模型参数。结果表明，在循环弯曲下电阻持续增加，功率输出下降。TEG 的电阻和功率输出随弯曲半径而变化。基板与TE薄膜的厚度比对功率输出和能量转换效率有很大影响。可以从模型中获得临界弯曲半径，为未来灵活的 TEG 设计提供指导。