Thermal cycling induced load on copper-ribbons in crystalline photovoltaic modules

Solar module lifetime is limited by the fatigue behavior of its cell interconnectors: the copper-ribbons. Every change in temperature induces thermo-mechanical stresses in the module components due to their thermo-mechanical mismatch. The purpose of this work is to quantify this load on the copper-ribbons between the individual cells of a cell string during a thermal cycling test by measuring cell displacement using digital image correlation and to compare the results to finite element analysis (FEM). Furthermore with help of FEM the influences of different materials were investigated, allowing material and layout optimizations with respect to copper-ribbon loading.