Laser welding utilizes the excellent directionality and high power density of the laser beam to work. The laser beam is focused into a very small area through an optical system, forming a heat source area with highly concentrated energy at the weld in a very short time, thereby melting the welded material and forming a strong weld point and weld.

As a new type of welding method, laser welding is in a stage of rapid development. Compared with other welding methods, it has small welding spots and high welding dimensional accuracy; the non-contact welding method makes the product less deformed, the welding quality is high, the efficiency is high, and it is easy to realize automated production.

From the manufacture of lithium battery cells to the battery PACK grouping, welding is a very important manufacturing process, which will affect the battery quality in terms of conductivity, strength, air tightness, metal fatigue and corrosion resistance. The selection of welding methods and welding processes will also affect the cost, quality, safety and consistency of the battery.

Among many welding methods, laser welding finally stands out with the following advantages:

1 High energy density, small welding deformation, small heat-affected zone, which can effectively improve the precision of parts, smooth weld without impurities, uniform and dense, and no additional grinding work is required

2 It can be precisely controlled, with a small focused spot, high-precision positioning, and easy to automate with a robot arm, improving welding efficiency, reducing working hours, and reducing costs

3 When welding thin plates or thin-diameter wires, it will not be as susceptible to remelting as arc welding

The structure of the battery, such as electrodes, wires, and shells, often contains a variety of metal materials such as steel, aluminum, copper, and nickel. Whether it is welding between one material or between multiple materials, it places high demands on the welding process. The process advantage of laser welding is that it can weld a wide variety of materials and can achieve welding between different materials.

The automated laser production line for lithium batteries generally includes processes such as cell loading, OCV sorting, secondary code scanning and grouping, AI detection of pole addressing, pole cleaning, laser welding, automatic weld scar detection, module stacking, stacking detection, module welding, welding detection, and module unloading. We believe that the key to the technology in the entire production line lies in the material transmission system, adaptive system, visual positioning system, MES manufacturing execution management, etc., which are also important technical supports for adapting to small-batch and multi-variety production forms.