THE LASER USER
ISSUE 115 MARCH 2025 LASER WELDING
inertia increases with the size of the aperture, as larger apertures require correspondingly larger mirrors. The optics used in the system are equipped with high-performance scanner drives that precisely follow the designated paths, even at high frequencies.
Up to six welds per second
Figure 3: The process for the demanding material mix of AL1xxx to Hilumin was developed at Scansonic's Laser Application Center. One of the challenges is maintaining a consistent weld depth. This was achieved with a sheet thickness of t = 0.6 mm, using a single-mode laser with a power output of 975W and a welding speed of 700 mm/s. Copyright: Scansonic MI GmbH.
To detect the precise location of the battery cells and the cell connectors, a camera system moves into position before the clamping device is positioned. Communication between the camera system, the drive units of the clamping devices, and the laser scanners is critical for the entire process. Real-time communication in microseconds is required. The laser optic is also optimised to meet this requirement. Dynamic mirror movements ensure that the predefined welding paths are travelled with spatial precision and high speed. This is also supported by the large scan field of the optics. For the described project, a scan field of 160 x 160 mm was programmed, while technically, fields of up to 400 x 310 mm are possible.
In its current configuration, the system can perform four laser welds per second. Production of the entire battery pack with 960 cells therefore takes four minutes because in serial production, two welding systems operate in parallel on one battery pack. To further increase the processing speed in mass production, the system could be equipped with additional laser scanners. Multiple compact scanners can be arranged on an application rack in this way. This allows the laser process to be easily and cost- effectively expanded through parallelisation. Fast communication between the various components of the system is ensured.
Convincing results in the pilot series system
Figure 4: Battery contact welding requires innovative welding strategies. High mechanical stability must be achieved with low electrical resistance, while simultaneously minimising the risk of welding through the processed battery cell. Copyright: Scansonic MI GmbH.
based on the scanner’s deflection. While the highly dynamic collimation and synchronisation with the movement of the scanner axes are more complex compared to using F-theta lenses, the result is high processing precision and significantly reduced thermal lensing. Unlike pre-focusing optics, F-theta optics alter the laser beam’s impact point on the F-theta lens with every scanner movement. Each movement generates a "new" thermal lensing effect and focus shift due to localised heating.
Trust in a reliable process
During the welding operation, the optic moves on a predefined welding path relative to the material, whereas other laser welding optics have a more static operation. Not least, the simultaneous welding of Hilumin and aluminum demands a great deal of know-how about process
Axel Luft is Managing Director at Scansonic MI and at B.I.G. Technology Services. He is responsible for international sales, marketing activities & technical services.
SEE OBSERVATIONS P30 19 parameters and welding strategies (Figure 3).
The optimisation of process parameters plays a critical role. The scanners move the laser focus along predefined paths at specified speeds over the working plane area in which the materials are to be welded. It is essential that the scanner can accurately translate the chosen parameters into the desired motion. The higher the accelerations—caused by factors such as high frequencies or amplitudes—the more the inertia of the scanner mirrors comes into play. This
In 2023, Bergmann & Steffen presented the automotive manufacturer with a laboratory model that incorporated the system and the on-the-fly laser welding unit. Extensive tests produced such convincing results that the company subsequently ordered a pilot series system, which has been in operation since 2024. This system is intended to validate the mass production of various battery packs. Weld quality and process stability are being checked. The system will soon be integrated into serial production.
Contact: Axel Luft
info@scansonic.de www.scansonic.de/en/
Co-author Pravin Sievi is a product owner at Scansonic MI
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