Stress Mapping by Confocal Raman Spectroscopy on Solar Cells and Modules

In this work, we show the latest progress in the confocal micro-Raman spectroscopy for determination of stress within embedded solar cells. We present measurements proving that the module front glass has no influence on the stress measurement. We also present the first large area stress mapping on a quarter solar cell within a single-cell laminate. A stress map of the busbar end shows the superposition of the soldering induced tensile stress at the end of a busbar and the overall compressive stress from lamination. The stress mappings show the same trend as finite element simulations. We obtain a maximum relative compressive stress in the center of the laminated solar cell of about 50 MPa from the Raman spectroscopy and the FEM simulation.