At present, the square aluminum battery accounts for a large proportion of the power battery. In the welding process of the battery, the welding of the aluminum battery is more difficult. This is because the special nature of the aluminum makes the welding prone to problems such as bulging, blowholes, etc. At the corner, where is the difficulty in welding the square aluminum shell power battery?
The outer shell of the power battery is generally made of aluminum alloy, which has the advantages of easy forming, high temperature resistance, corrosion resistance, and good electrical conductivity. The main problem of laser welding aluminum alloy materials is that the aluminum alloy has a high emissivity to the laser and its thermal conductivity is high, which causes laser welding to be difficult.
2. Welding method
The thickness of the shell of the square battery is generally 1mm or less, and the mainstream is based on the difference in capacity between 0.6mm and 0.8mm. Laser welding square power battery shell can be divided into side welding and top welding: side welding has less influence on the interior of the battery, spatter will not enter the inside of the shell, but it will easily produce bumps after welding, which will affect the subsequent process; Because the top welding is welded on a flat surface, the requirements for shelling and positioning of the front process are very high, so the automation is demanding.
3. Welding defects
When laser welding of aluminum, it is easy to cause problems such as bulges, blowholes, and internal air bubbles. The reason is that the diameter of the fiber core is too small or the laser energy is set too high. There are also many factors of splashing, such as the characteristics of the material itself, the cleanliness of the material, etc. The main decisive factor is the stability of the laser.
Therefore, when laser welding square aluminum shell power battery, the welding craftsman will choose the appropriate laser and welding process parameters according to the factors such as the thickness of the battery, pulling force, etc. to ensure that the welding effect reaches the requirements of the power battery manufacturer. When welding, the corners are prone to problems, which can be solved by adjusting the welding speed according to the actual situation.