At present, the square aluminum shell battery occupies a large proportion in the whole power battery. In the welding process, due to the particularity of the aluminum alloy shell, problems such as bulge and pores appear in the welding process, especially in the corner part.

1. Battery raw materials

The shell of the power battery is made of aluminum alloy, which has the characteristics of easy forming, high temperature resistance, corrosion resistance and conductivity. The main problem of laser welding of aluminum alloy is that aluminum alloy has high emissivity and high thermal conductivity, which makes it difficult to perform laser welding.

2. Welding method

The thickness of the square battery shell is usually less than 1 mm, the mainstream is 0.6 mm and 0.8 mm, and the laser welding of the square power battery shell is mainly side welding and top welding, side welding on the internal impact of the battery core is very small, the splash material will not penetrate the shell, but in the welding process will appear a bump, affect the subsequent processing; Top welding is carried out on a flat surface, which requires a high degree of automation for the shell entry and positioning of the front process.

3. Difficulties in welding

In the laser welding of aluminum materials, because the diameter of the fiber is too small, or because the laser power is set too high, so there will be problems such as bulge, pores and bubbles, there are many factors affecting the splash, including the characteristics of the material itself, the cleanliness of the material, and the stability of the laser is the main factor affecting the laser.

In the production and assembly, the welding technology of square aluminum shell lithium battery mainly includes: core soft joint and cover plate welding, sealing nail welding, etc. Therefore, the selection of laser welding equipment should be customized according to the welding process requirements. Xinde Laser Company can provide users with free proofing, laser welding program design, can really meet the needs of users for welding.