Roozbeh Nabavi, José Reinoso, Eelco Jansen, Raimund Rolfes
|Titel:||Thermo-mechanical aspects of the co-firing process in multi-crystalline silicon solar cells|
One of the principal issues during the production of solar cells concerns the so-called co-firing process. In this procedure, the laminated structure composed of Silicon (mono-crystalline or multi-crystalline). Aluminum-paste and Silver-paste is heated up to 850°C, and afterwards is cooled down up to room temperature. As a consequence of the significant mismatch between the thermal expansion coefficients of the adjacent constituents within the laminate, a residual curvature is noticeable which gives an indication of the internal residual stress field. In order to capture this bowing behavior of the structure first a detailed review on the mechanical properties of different constituents of the silicon solar cells, with a special focus on silicon due to its anisotropic mechanical behavior, has been performed. The complex structure of multi-crystalline silicon has been produced based on the Voronoi-Tessellation algorithm. Consequently the effect of crystallographic texture on the final configuration of the solar cell after the co-firing process through Monte Carlo simulations using FEM approach has been investigated.