Several major technical difficulties of Power battery welding
In general, the power battery shell welding mainly have two ways welding : side welding and top welding ,they have their own advantages and disadvantages, and power battery aluminum shell very easy prone to bulge, stomatal, fraud or other issues and the square battery welding is prone to problems at the corners because of the special nature of its materials .Here some difficulties of power battery welding as below :
1.The process difficulties of power battery welding
For generally ,the thickness of power battery aluminum shell require below 1mm,currently mainstream manufacturers have 0.6mm and 0.8mm these two shell material thickness according the different capacity of battery .Welding is mainly divided into side welding and top welding,side welding have less impact for internal cell ,and splash will not easily into the shell cover inside.
As the welding may lead to bulging, which will have some minor impact on the assembly process of the follow-up process,Therefore, the side of the welding process have high requirement for the stability of the laser, the cleanliness of the material and the cover with the power battery aluminum shell with the gap.The top welding process due to welding on one side, can be more efficient galvanometer scanning welding,but have high requirements for former process into the shell and positioning and equipment automation.
2.Solving Difficulties of Aluminum shell power battery
At present the power battery aluminum shell accounts for the entire power battery 90% above. Aluminum laser welding is more difficult, will face welding convex surface problems, stomatal problems, fires, internal bubble problems. Surface protrusions, stomata, internal air bubbles are fatal to laser welding, and many applications have to stop or think of ways to circumvent them for these reasons.
Many battery manufacturers in the initial R & D will be a big headache for this reason, mainly due to the use of optical fiber core diameter is too small or laser energy set too high. There are many factors, such as cleanliness of material, purity of material itself, characteristics of material itself, and so on. The decisive effect is the stability of the laser.
In the power battery welding, the welding process technical personnel will be based on the customer's battery material, shape, thickness, tensile requirements and other appropriate laser and welding process parameters, including welding speed, waveform, peak, welding head tilt angle to set a reasonable Welding process parameters to ensure that the final welding results to meet the requirements of power battery manufacturers.
3.Welding Difficulties of Square Power Batteries
Square battery with the accuracy of the incoming and other factors, the welding corner of the most prone to problems, need to continue to explore in accordance with the actual situation, adjust the welding speed can solve such problems. Circular batteries do not have this problem, but the subsequent integration of the battery module is more difficult.