A lot of raw material can be saved when welding high-performance electronics. This is the result of a study at the German Electron Synchrotron Desy of the Helmholtz Association in Hamburg.
High-performance electronics in electric cars are a key technology that ensures optimum battery and motor performance. Together with the technology company Trumpf and the Fraunhofer Institute for Laser Technology ILT, the Hamburg researchers have now investigated laser welding processes in the production of electric cars. It was found that a laser with a green wavelength produces far fewer rejects than other laser welding processes, which saves a lot of raw material, as electric vehicle manufacturers have to weld several billion joints to the highest quality.
Copper is the most important material for the production of core components for e-mobility. The ILT and Trumpf team investigated the laser welding processes using two different laser systems, a NIR laser (near infrared range) and a laser with a green wavelength. Copper absorbs only around 5% of the laser radiation in the near infrared range and dissipates most of the heat. Both lead to considerable problems during welding. Copper can be welded better using lasers with a green wavelength because it absorbs the green wavelength significantly better than the infrared wavelength. Because the material reaches its melting temperature more quickly as a result, less laser power is required.
To investigate the welding processes in detail, the ILT staff, in collaboration with the Chair of Laser Technology at RWTH Aachen University, used Desy's Petra III X-ray light source in the Helmholtz Center's experimental setup. This radiation can be used to look inside the molten zones and also make the molten dynamics visible. The use of X-ray radiation from the particle accelerator provides several thousand to 10,000 images per second.
