What are the welding applications and difficulties of the fiber laser welding machine in the battery field?

What are the welding applications and difficulties of the fiber laser welding machine in the battery field?

High-efficiency and precise laser welding can greatly improve the safety and service life of automotive power batteries, and will bring revolutionary advancements in automotive power technology in the future; there are many laser welding parts for power batteries, which require pressure resistance and night leakage testing, and most of the materials are Aluminum, because of the difficulty of welding, has higher requirements on welding process.

The welding of power battery shell is mainly side welding and top welding. Both sides have advantages and disadvantages. Aluminum shell batteries are prone to problems such as bumps and pores due to the particularity of their materials. Square batteries are welded at corners. Prone to problems.

Difficulties in welding square power battery

Due to factors such as the matching accuracy of the incoming materials, the square battery is most likely to have problems during welding. It is necessary to find out the countermeasures according to the actual situation. Adjusting the welding speed can solve this type of problem. The round battery does not have this aspect. Problems, but the subsequent integration of battery modules is more difficult.

Welding difficulties of aluminum shell power battery

At present, aluminum shell batteries account for more than 90% of the entire power battery. The laser welding of aluminum is difficult, and it will face the problems of welding surface protrusions, pores, and internal bubbles. Surface protrusions, pores, and internal bubbles are fatal to laser welding. Many applications have to stop or find ways to circumvent them due to these reasons. Many battery manufacturers will be troubled by this in the initial stage of research and development. The main reason is that the fiber core diameter is too small or the laser energy is set too high. In power battery welding, the welding process technicians will depend on the customer’s battery Material, shape, thickness, tension requirements, etc. Choose appropriate laser and welding process parameters, including welding speed, waveform, peak value, welding head inclination angle, etc. to set reasonable welding process parameters to ensure that the final welding effect meets the power battery manufacturer Requirements.

Technical difficulties in power battery welding

Generally, the thickness of the shell is required to be less than 1.0mm, and mainstream manufacturers currently have two methods for the thickness of the shell material according to the battery capacity: 0.6mm and 0.8mm. Welding methods are mainly divided into side welding and top welding. The main advantage of side welding is that it has a small impact on the inside of the cell, and spatter will not easily enter the inside of the cover. Since the welding may cause bumps, which will have a slight impact on the subsequent process assembly, the side welding process has higher requirements on the stability of the laser, the cleanliness of the material, and the matching gap between the top cover and the shell. Because the top welding process is welded on one surface, a more efficient galvanometer scanning welding method can be used, but it has high requirements for the housing and positioning of the previous process and the automation of the equipment.