Power modules subjected to cyclic power operation experience thermomechanical fatigue. Herein, the epoxy molding compounds and creep behaviors of solder joints promoted the strain hardening of the Cu clip wiring and caused failure to the power module during the power operations. In the Cu clips, the grain size was refined by 90% from the failure stage compared to the initial state, and an increase in hardness was observed. The results indicate that constraints of EMC and the creep behaviors of solder joints are other critical factors for the role of bare Cu clip strain hardening of EV power modules.

中文翻译：

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热机械疲劳导致压铸型 EV 功率模块上铜夹布线的意外应变硬化

经受循环电源操作的电源模块会经历热机械疲劳。在此，环氧模塑料和焊点的蠕变行为促进了 Cu 夹布线的应变硬化，并在电源操作期间导致电源模块出现故障。在 Cu 夹中，与初始状态相比，失效阶段的晶粒尺寸细化了 90%，并且观察到硬度增加。结果表明，EMC 的约束和焊点的蠕变行为是影响 EV 功率模块裸铜夹应变硬化作用的其他关键因素。