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.