Lithium battery laser welding process difficulties

Laser welding uses a high-energy-density laser beam as a heat source to melt the workpiece and form a specific molten pool by controlling parameters such as the width, energy, peak power, and repetition frequency of the laser pulse. With the increasing labor costs in today's market and the advancement of technology, laser welding has become a hot welding equipment in the laser industry. What are the technical difficulties in welding lithium battery packs?

1. The battery casing of aluminum alloy material occupies 90% of the power. Its difficulty is due to the high reflectivity of aluminum alloy and the sensitivity of air holes, as well as the inevitable problems in the welding process, mainly air holes and thermal cracks and burst.

3. Hot cracks: Because aluminum alloy is a typical eutectic alloy, hot cracks are prone to occur during the welding process, such as welding crystal cracking, HAZ liquefaction cracking, etc., due to the analysis of the composition of the weld zone, the grain boundaries are melted , under the action of stress, liquefaction cracks will be generated at the grain boundaries, which will lead to a decrease in the performance of the welded joint.

4. Explosion (also known as splash), there are many reasons for the explosion, such as the cleanliness of the material, the purity of the material, the nature of the material itself, etc., and the stability is the key to the explosion. The surface of the shell is raised, air holes, and air bubbles. The main reason for this phenomenon is that the diameter of the optical fiber is too small, or the power setting of the laser is too high. The beam quality and welding performance claimed by some manufacturers do not mean that, With good beam quality, it can adapt to the surfacing welding with large melting depth.