Post-Processing Thickness Variation of PV Module Materials and its Impact on Temperature, Mechanical Stress and Power

We measure the thickness of the encapsulation layers in photovoltaic modules using scanning acoustic microscopy and optical microscopic imaging. Based on the measurement data, we analyze the impact of thickness variation on the operating temperature of the module, its peak power and mechanical stresses in the solar cells during lamination and under load testing conditions. Especially in cell-free areas we find an inhomogeneous thickness attributed to a bending of the backsheet, which has a small impact on the backsheet coupling gain. Even though we find significant deviation in the thicknesses of the encapsulation layer of up to 150 mm, the impact of encapsulant thickness under the investigated conditions is small and mainly attributed to changes in operating temperature.