Microstructural Characterization and Unified Reliability Assessment of Aged Solder Joints in a PV Module

In this article, the finite-element method (FEM) along with experimental analysis was used to establish a mission profile-based reliability assessment of solder joints of the photovoltaic module under thermal cycling conditions. While considering the uncertainties of the solder joint lifetime model that leads to more realistic results, this method is able to estimate the time if the probability of solder joint failure reaches 10%. Several conditions, including standard and nonstandard cases, were simulated and performed to obtain the fatigue lifetime models. The experimental results, that is, scanning electron microscopy (SEM) along with X-ray tomography, showed that more intermetallic compounds and microvoids are formed in the nonstandard conditions (STCs). As a result, the non-STC leads to the accelerated failure in the solder interconnection, which is consistent with the FEM outcomes. In the end, a real case study was considered to investigate the efficiency of thermomechanical fatigue reliability model.