FEM simulations of back contact solar modules during temperature cycling

Abstract

This paper is focused on the reliability performance of novel back contact solar modules. Tn this study the mechanical integrity of the interconnect structures of back contact modules is analyzed by FEM-simulations. The solar module lifetime is limited by mechanical stresses which arise from temperature cycles. These temperature cycles are caused by day to night shifts. The reliability of photovoltaic modules under these load conditions is tested by the IEC standard 61215. The according temperature profile is created for the FEM simulations and tested with the novel back contact solar modules. A classic module assembly applying H-patterned cells is taken as reference case. The result evaluation shows high localized stresses in the interconnection structures of both module assemblies. However, these localized stresses do not cause ultimate cracks of the interconnection structures and thus may help to reduce the stress in adjacent sections of the assembly. The goal of the study is to compare the mechanical behavior of these two types of photovoltaic modules. The results of this investigation figure out, where are critical structural elements in the photovoltaic modules.