Analysis of solder joint degradation and output power drop in silicon photovoltaic modules for reliability improvement

With the growing worldwide demand for clean, reliable, and economical energy supply, Photovoltaic (PV) modules have raised the bar for the field over the last years. However, PV modules have shown some shortcomings as environment temperature influences not only the maximum power generation but also the life expectancy of the module. PV reliability has become a topic of extreme importance driven by the extension of the warranty period over the years. This study investigates the degradation of solder joints. A 2-D Finite Element Model (FEM) has been computed to evaluate the lifetime of the solder joints and the cell power drop using accelerated thermal cycling tests in the range of -40 to 85 degrees C according to IEC 61215 standard. 2 models were used to predict the lifetime. In addition, 5 PV modules were conducted to thermal cycling tests to validate the model. The results reveal that during the thermal cycling test, the rear solder is damaged in a much earlier stage than the top solder. The deterioration of the rear solder area becomes steep after 1000 cycles and the power loss of the module reaches 2% between 600 and 750 thermal cycles depending upon the mathematical model. When compared to experimental results, the Coffin-Mason model is more accurate, with a maximum data disparity of 4.3%. A solder without any residual stress will eventually pass the 600TC test according to CSA/ANSI C450-18 and IEC TS 63209 ED1 standards. These findings inform on the solder joint durability which is an important parameter for the reliability analysis of a PV module.

Automated summary

The study highlights the impact of environmental temperature on PV module reliability, with a focus on solder joint degradation. Two mathematical models were used to predict the solder joint lifetime, which were validated through thermal cycling tests.