Side welding and top welding are the two main welding methods for power battery casings. Each has its own processing advantages and disadvantages. At the same time, most power batteries are made of aluminum shell materials due to their material characteristics. The processing process is prone to bulges, fire, and pores. And other issues

In particular, Prismatic Cell is most prone to problems when welding at corners.

The following will introduce to you some difficulties in power battery packaging welding:

1. Technical difficulties in power battery welding

Generally, the thickness of the aluminum shell of power batteries is required to be less than 1.0MM. Mainstream manufacturers currently use two shell material thicknesses of 0.6mm and 0.8mm depending on the battery capacity. Welding methods are mainly divided into side welding and top welding. The main benefit of side welding is that it has less impact on the inside of the battery core and spatter will not easily enter the inside of the shell cover.

Since bulges may occur after welding, which will have a slight impact on subsequent assembly processes, the side welding process has higher requirements on the stability of the laser, the cleanliness of the material, and the matching clearance between the top cover and the aluminum shell of the power battery. . Since the top welding process is welded on one surface, a more efficient galvanometer scanning welding method can be used, but it requires high requirements for shell insertion and positioning in the previous process, as well as high automation requirements for the equipment.

2. Difficulties in welding aluminum shells of power batteries

At present, the aluminum shell of power batteries accounts for more than 90% of the entire power battery. Laser welding of aluminum materials is difficult, and it will face problems such as bulges on the surface of the weld mark, pore problems, explosion problems, internal bubble problems, etc. Surface bulges, pores, and internal bubbles are fatal injuries to laser welding. Many applications have to stop or find ways to avoid them due to these reasons.

Many battery manufacturers struggle with this in the early stages of research and development. The main reason is that the fiber core diameter used is too small or the laser energy setting is too high. There are many factors that cause explosions (also called splashes), such as the cleanliness of the material, the purity of the material itself, the characteristics of the material itself, etc. The decisive factor is the stability of the laser.

In power battery welding, welding process technicians will select the appropriate laser and welding process parameters according to the customer's battery material, shape, thickness, tension requirements, etc., including welding speed, waveform, peak value, welding head tilt angle, etc. to set a reasonable Welding process parameters to ensure that the final welding effect meets the requirements of power battery manufacturers.

3. Difficulties in welding Prismatic cell

Due to factors such as the matching accuracy of incoming materials, Prismatic cell are most likely to have problems at the corners during welding. This needs to be continuously explored based on the actual situation. Adjusting the welding speed can solve such problems. Circular batteries do not have this problem, but subsequent integration into battery modules is more difficult.

The difficulties of power battery welding are shared with you here. As long as we understand these difficulties in power battery welding and avoid them one by one, I believe we will be able to break through the welding difficulties.

From the above content we can summarize the following inspirations:

1. The reasons why aluminum-shell batteries cause false fires: the cleanliness of the material, the purity of the material itself, the characteristics of the material itself, etc. The most decisive key component is the stable performance of the laser.

2. Corner welding of Prismatic Cell requires slowing down the welding speed.

3. Side welding has the least impact on the battery core, and spatter will not fall into the casing.

4. Top welding requires a galvanometer system, which requires high automation.

5. Surface bulges, pores, and internal bubbles are fatal injuries to laser welding. Therefore, technicians need to select the appropriate laser and welding process parameters based on the battery material, thickness, shape and tension requirements, etc.