For practical industrial applications, enhancing the longevity and the reliability of thermoelectric modules (TEMs) is equally as crucial as improving their conversion efficiency. This study proposes a strategy for extending the lifespan and introduces the quality evaluation criteria for the most extensively used commercial bismuth telluride TEM. By varying the soldering pressure during module assembly, its impact on the quality of the module’s internal interfacial connections was investigated, via analyzing its contact resistivity, shear modulus, and antifatigue ability through thermal cycling tests. The findings reveal that increasing the soldering pressure leads to a slight reduction in interfacial contact resistivity and has no significant effect on the shear modulus but notably enhances the module’s antifatigue ability during thermal cycling tests. According to the SEM results, it can be evidently deduced that the aforementioned phenomena are directly correlated with the size and quantity of voids distributed in the solder layer, which is regarded as the origin of antifatigue ability. Thus, it can be inferred that augmenting the soldering pressure represents an effective approach to prolonging the lifespan of TEMs assembled by using the soldering method. Furthermore, the existence of voids within the solder layer can serve as a criterion for an initial assessment of module longevity. This study provides a reference for both the industrial assembly and lifespan evaluation of commercial bismuth telluride TEMs.

中文翻译：

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焊接压力对热循环下热电模块寿命的影响


对于实际工业应用，提高热电模块 (TEM) 的使用寿命和可靠性与提高其转换效率同样重要。本研究提出了延长寿命的策略，并介绍了最广泛使用的商用碲化铋 TEM 的质量评估标准。通过改变模块组装过程中的焊接压力，通过热循环测试分析其接触电阻率、剪切模量和抗疲劳能力，研究其对模块内部界面连接质量的影响。研究结果表明，增加焊接压力会导致界面接触电阻率略有降低，对剪切模量没有显着影响，但显着增强了模块在热循环测试中的抗疲劳能力。根据SEM结果可以明显看出，上述现象与焊料层中分布的空隙的大小和数量直接相关，这被认为是抗疲劳能力的根源。因此，可以推断，增加焊接压力是延长使用焊接方法组装的TEM寿命的有效方法。此外，焊料层内是否存在空隙可以作为模块寿命初步评估的标准。该研究为商用碲化铋TEM的工业组装和寿命评估提供了参考。