Investigations of Different Soldering Failure Modes and their Impact on Module Reliability

Future Photovoltaic is being increasingly forced to reduce costs and increase module power by constant or better module reliability [1]. So over the last years a radical decrease of module prices is observed on the contrary the module power changes to higher classes. This indicates that the common used materials (e.g. frames, solder ribbon, wafer, metallization etc.) join their physical limits. This contains different challenges due to reliability. For future applications such requirements will be e.g.:
• Smaller frames vs. high loads
• Thinner glass substrates vs high impacts
• Smaller interconnection area vs. higher current density and higher thermal dissipation
• Smaller ribbons vs higher cell breakage rate & higher soldering challengesThis represents only a small number of the challenges facing the Photovoltaic industry in the future. The aim and role of PV industry is to realize efficient and reliable modules. This paper will present detailed data on soldering failure modes during string assembly and reliability testing, and the long-term mechanical and electrical stability of the solder joints and their impact on the long-term efficiency of the modules. The data will show that different failure modes have different effects on the quality of interconnections as well as on the reliability of the modules.