Investigation of Temperature Homogeneity during Infrared Soldering of Silicon Solar Cells using the Finite Element Method

In the production of silicon photovoltaic modules, copper ribbons are connected to the electrodes of solar cells using infrared soldering through automated stringer machines. Despite its efficiency and high throughput, infrared soldering results in inhomogeneous heating of the solar cells. Accurately measuring the solar cell temperature during the soldering process within the stringer poses a significant challenge, hindering process optimization to reduce this inhomogeneity. This study presents a novel finite element model to simulate the infrared soldering process, which calculates the solar cell temperature based on factors such as the applied electrical power, the radiation duration from the infrared emitters, and the hotplate temperature. The model is validated using thermocouple measurements at various points on the solar cells during the soldering process, showing a maximum difference of (8 ± 4) K in the peak temperature region between the simulation and experimental data. This FEM model can easily be adapted to new solar cell technologies and various solar cell sizes. Thus, a robust finite element model is developed to accurately determine the solar cell temperature during the infrared soldering process.