OS0508 Thermal Stress Analysis of Tabbed Solar Cells Using Solder Alloy and Conductive Film
Details
Aiming at understanding the thermal deformation characteristics of two solar cell configurations, finite element thermal stress analysis is carried out in this investigation. This study covers the manufacturing process and operating conditions including three thermal cycles of different environments in order to determine the long term effects of residual stresses. While the first solar cell model is tabbed by lead-free solder, the second model by conductive film (CF). A high temperature soldering process causes stress of the solar cell due to the different thermal expansion coefficients of materials; stress could weaken the bond and reduce reliability of the cell. Also when a photovoltaic (PV) module is placed under the sun, solar irradiation will generate a temperature distribution across its surface. The conductive film requires lower temperature for its bonding with beautifully finished bonded areas. In this study, first, finite element analysis (FEA) was carried out for manufacturing process using both solder and CF bonding. Then, three temperature cycles considering different environmental operating conditions were applied to the analysis to understand how thermal cycles affect the residual stress developed during manufacturing process of solar cell. Using times of six months for solder and one month for CF bonded cell were considered for the analysis. This investigation provides a comparison of thermal stress between solder and CF as bonding materials of solar cells in order to determine which offers best reliability in the long term.
