The British use laser and German optical technology to weld high-tech aluminum

Recently, WMG of University of Warwick developed a new process of laser welding aluminum battery box on behalf of major automobile manufacturers, which is ready for mass production. The WMG team selected ALO4-O processing optical devices from Scansonic Berlin, a well-known manufacturer of laser processing systems. As you can see, ALO4-O is designed specifically for welding battery shells. As explained by experts, the laser processing head combines the tactile seam tracking of the ALO product series with the oscillating laser beam of remote optical devices.

WMG explained that many of the characteristics of ALO4-O are convincing in the process of finding the best optical devices for research projects. Because it combines near-field scanning optical devices with tactile seam tracking and rapid modulation of laser power through oscillating laser beams. In this way, you can control the supply of heat and customize the structure of the joints. Ultimately, welding cracks will also be eliminated, and processing speed will also be improved.

As is well known, battery packs form the interface between the vehicle's bottom structure and the road. The construction of these boxes is not simple. For example, they must have a sufficiently high level of collision resistance and dimensional stability, as well as water and air tightness. Meanwhile, production costs should be as low as possible. Experts emphasize that in order to reduce weight, more and more vehicle manufacturers are starting to use high-strength 6xxx aluminum alloy. However, the problem is that these types of aluminum are very prone to thermal cracking, which makes welding difficult.

Almost twice the welding strength of the battery casing
As part of the testing series, the project team was able to achieve significant improvements in three important parameters of the aluminum welding process compared to non oscillatory contact welding. Firstly, it should be pointed out that at medium to high speed machining speeds (4.8 meters/minute), jet oscillation can increase the joint strength by up to 70%. Secondly, in order to achieve the target connection strength, the heating capacity can be reduced by 50%. Due to the combination of wire feeding and beam oscillation, so-called larger light spots than welding wires can be avoided. This can also reduce the laser power during the welding process, which is why it can reduce the threat of thermal deformation and, of course, save energy. Thirdly, the laser beam oscillation test shows that the gap bridging is ensured to be up to 45% of the thickness of the upper material of the aluminum component to be welded. This can even be comparable to the pure remote laser welding system.

This project not only proves the feasibility of welding the battery casing, but also develops a prototype. WMG and Scansonic's laser application laboratories have also made sufficient preparations to further optimize the production process of battery shells.

Source: Laser Network