Thermomechanical stressing of solar cells

Abstract

This paper describes recent developments made to the finite element modeling of solar cells, extending its capability to handle viscoplastic behavior. It also presents the validation of this approach and results obtained for an interconnection of solar cells. Lifetime predictions are made using the creep strain energy based models of Darveaux. This study discusses the analysis methodologies as implemented in the ANSYS finite element simulation software tool. The aim of this paper is to improve reliability interconnection of solar cells and to increase durability of these structures. Three-dimensional finite element analysis has been applied to determine the independence on different types of substrates and solder pastes. The interpretations of results are divided into two parts. The first part of evaluation discusses the stress distribution in solder joints depend on material properties. Determining a place in the solder with the maximal stress values and determining the stress is distributed for interconnection of solar cells are the result of this investigation. The possible danger solder joint crack is in the place with the maximal stress value. The second part of evaluation discusses the plastic work (DeltaWave ) (Zahn, 2005), where "DeltaWave" is the element volumetric average of the stabilized change in plastic work within the controlled solder element thickness, the number of cycles to crack initiation, the crack propagation rate and giving the total number of cycles to 63.2% sample failure