Generally speaking, the welding of power lithium battery shell is mainly divided into two methods: side welding and top welding. They have their own advantages and disadvantages, while the aluminum shell of power lithium battery is prone to bulges, pores, fraud or Problems such as square batteries are prone to problems when soldered at the corners. The following will introduce some difficulties in the packaging and welding of power lithium batteries:

1. Technical difficulties of power lithium battery welding

Generally, the thickness of the aluminum shell of power lithium batteries is required to be less than 1.0 mm. At present, mainstream manufacturers mainly use 0.6mm and 0.8mm in thickness of shell materials according to different battery capacities. The welding methods are mainly divided into side welding and top welding. The important advantage of side welding is that it has less influence on the inside of the cell, and spatter will not easily enter the inside of the shell cover.

Since it may cause bulges after welding, it will have a slight impact on the assembly of the subsequent process. Therefore, the side welding process has a high impact on the stability of the laser, the cleanliness of the material, and the matching gap between the top cover and the aluminum case of the power lithium battery. Require. In the top welding process, since it is welded on one surface, a more efficient galvanometer scanning welding method can be used, but it has high requirements on the shelling and positioning of the previous process, and high requirements on the automation of the equipment.

2. Difficulties in welding the aluminum shell of the power lithium battery

At present, the aluminum shell of the power lithium battery accounts for more than 90% of the entire power lithium battery. Laser welding of aluminum materials is difficult, and it will face the problem of surface bumps, pores, explosions, and internal bubbles. Surface bulges, pores, and internal air bubbles are the fatal injuries of laser welding, and many applications have to be stopped or avoided due to these reasons.

Many battery manufacturers will be troubled by this in the early stage of research and development. The main reason is that the core diameter of the optical fiber used is too small or the laser energy setting is too high. There are also many factors that cause explosions/splashes, such as the cleanliness of the material, the purity of the material itself, the properties of the material itself, etc. The decisive use is the stability of the laser.

In the welding of power lithium batteries, the 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 inclination angle, etc. to set reasonable settings The welding process parameters to ensure that the final welding effect meets the requirements of power lithium battery manufacturers.

3. Difficulties in welding square power lithium batteries

Due to the influence of factors such as the matching accuracy of incoming materials, the square battery is most likely to have problems at the corners during welding. It is necessary to continuously explore according to the actual situation and adjust the welding speed to solve such problems. Round batteries do not have this problem, but subsequent integration into battery modules is more difficult.

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