Stress-Minimized Laser Soldering of h-pattern Multicrystalline Silicon Solar Cells

Stress-minimized soldering processes are required to bond interconnectors to solar cells. Different process strategies for the simultaneous and quasisimultaneous energy deposition are evaluated with regard to the joining quality and the process time. A numerical benchmarking index is developed to assess the optimal laser parameters. A quasisimultaneous scanning strategy is designed to lower the total expansion of the interconnector during the process. The energy deposition with a fixed optic enables a simultaneous soldering of the interconnector over the complete length and lowers the process time to 1 s per interconnector. The laser soldering process lowers the diffusion of alloy components in the solder and enhances the mechanical resistance of the interconnector of more than 50% compared to conventional infrared-soldered samples.