Stories|Greener than Green: Laser Innovation for Stronger, Greener Electric Vehicles
Greener than Green: Laser Innovation for Stronger, Greener Electric Vehicles
New materials and analysis
Green lasers for better welding results
In order to build reliable electric cars and achieve the energy transition on our roads, manufacturers need fast and reliable laser techniques to manufacture their goods on a large scale and at low cost. One of the key applications is the high-precision, high-speed welding of copper joints. Until now, the welding joints formed have often been porous and leaky, leading to less-than-ideal material properties. Using high-brilliance X-rays, engineers have now been able to take a look inside the processes and study the causes in high-resolution videos. They have found that green laser light works better than conventional infrared light.
Electromobility poses major challenges for laser technology. This is because important components of electric motors are made of copper – not least because it dissipates heat well. Every electric car requires thousands of top-quality welded copper joints. The problem is that because copper dissipates heat so well, it only absorbs around five percent of the infrared radiation delivered by a conventional laser during the welding process, making it difficult to weld. A lot of material is wasted, and efficiencies are low. Porosity and spattering are often the result. This drives up costs and is bad for the environment.
Laser technology specialist TRUMPF wants to optimise laser welding. Working with the Fraunhofer Institute for Laser Technology (ILT), its engineers therefore compared the welding processes of various laser techniques as well as their outcomes, working with metal-ceramic substrates at the PETRA III High Energy Materials Science beamline, operated by HEREON. The brilliant X-rays produced by DESY not only allowed them to look inside the melt; they were even able to display the dynamics of the molten liquid in a movie, achieving a hitherto inconceivable quality. Their investigations revealed that lasers using visible green light – with a wavelength of around 500 nanometres as opposed to over 1000 nanometres, as in IR lasers – are much better for welding copper. The metal absorbs more light of this wavelength, reaches the melting point more quickly and requires less laser power. The process is much more efficient.
This means that industry can get closer to achieving the optimum weld seam using green laser light, speeding up the process and keeping the copper plates as thin as possible, while maximising durability and minimising material waste.
Partners involved
- TRUMPF
- Fraunhofer Institute for Laser Technology (ILT)
- DESY (PETRA III)
- HEREON (Beamline 07 P07 – High Energy Materials Science Beamline (HEMS)
