Laser welding is one of the earliest applications in industrial laser material processing. In most early applications, the welds produced by lasers were of higher quality, thereby increasing productivity. With the development of laser types, laser sources now have higher power, different wavelengths and a wider range of pulse capabilities. In addition, beam transmission, machine control hardware and software, and process sensors all promote better new developments in the laser welding process.
Laser welding has unique advantages, including low heat input, narrow fusion zone and heat-affected zone, and excellent mechanical properties of materials that were previously difficult to weld using a process that would generate greater heat input to the part. These properties make the weld formed by laser welding stronger and more attractive in appearance. In addition, the setup time required for laser welding is also much less. With the addition of laser tracking sensors, automation can be achieved, thereby reducing product costs. All these new technologies have further expanded the application range of laser welding. In many industries, fiber laser welding using different metals, component shapes, sizes and volumes has been successfully applied.
The increasing application of lithium batteries in electric vehicles and many electronic devices means that engineers use fiber laser welding in product design. The current-carrying components produced by copper or aluminum alloy are connected to terminals by fiber laser welding to connect a series of batteries in the battery. Laser welding aluminum alloy (usually 3000 series) and pure copper to form electrical contact with the positive and negative electrodes of the battery. All materials and material combinations used in the battery are candidates for the new fiber laser welding process. Overlapping, butting and fillet welding joints make various connections inside the battery. Laser welding of the lug material to the negative and positive terminals creates electrical contact with the package. The final battery assembly welding step, which is the joint sealing of the aluminum can, creates a barrier for the internal electrolyte. Since the battery is expected to work reliably for 10 years or more, laser welding can always be of high quality. Using the correct fiber laser welding equipment and technology, laser welding can consistently produce high-quality welds of 3000 series aluminum alloys.