Car manufacturers are facing fierce competition, and they must find ways to cut costs, especially in battery manufacturing. This means that the production line must become faster and more efficient. Assuming that manufacturers have exhausted all the potential of production line automation, there is only one way to achieve these two goals - by deploying more powerful lasers, having stronger beam shaping capabilities, more complex sensors, and ultra precise dynamic welding processing heads. Of course, this also requires a lot of process knowledge.

In electric vehicles, the cost of battery systems accounts for nearly 50% of the total vehicle cost. The processing quality during the manufacturing process determines the battery's storage capacity and service life. Shangtuo's laser processing technology can improve welding quality and production efficiency, reduce welding spatter, improve the reliability, consistency, and yield of battery manufacturing, and enhance the endurance of electric vehicles. Laser welding technology is becoming a key technology in the production and processing of new energy vehicles and their parts. It is known as "the brightest light, the fastest knife, and the most accurate ruler". It has outstanding advantages in reliability, accuracy, and efficiency.

Taking the current mainstream flat wire drive motor as an example, the laser technology involved includes welding of motor silicon steel sheets, repainting and welding of hairpin flat wires, and welding of motor busbars. The high repeatability and reliability of lasers can ensure that motors always achieve excellent conductivity in mass production. For example, in the paint removal process of flat copper wire, pulse laser ablation is a very economical and reliable process solution. Compared with mechanical processes such as planing and milling, the paint removal efficiency of laser processing can be improved by more than 80%.

In the field of car body, laser welding has long been famous. Now, many advantages, such as flexibility, automation and low production costs, have expanded the application of laser. From assembly, body in white, to the production workshops of car parts such as seat upholstery, laser applications can be seen almost everywhere. Regardless of whether it is a new energy vehicle or a traditional fuel vehicle, taking the hot formed parts of the vehicle body that can meet both strength and weight reduction/thinning requirements as an example, the mainstream choice for both main engine manufacturers and component manufacturers is 3D laser cutting.

Application range of laser welding equipment in lithium battery welding:

1. Welding of battery explosion-proof valve

The explosion-proof valve of the battery is a thin-walled valve body on the battery sealing plate. When the internal pressure of the battery exceeds the specified value, the explosion-proof valve body ruptures to prevent the battery from bursting. The structure of the safety valve is ingenious, and this process requires extremely strict laser welding process. Before continuous laser welding was adopted, the battery explosion-proof valve was welded by Pulsed laser, and continuous sealing welding was realized by overlapping and covering the welding spot with the welding spot, but the welding efficiency was low and the sealing was relatively poor. Continuous laser welding can achieve high-speed and high-quality welding, and welding stability, welding efficiency and yield can be guaranteed.

2. Welding of battery ear

The electrode ear is usually divided into three types of materials, with the positive electrode of the battery using aluminum (Al) material and the negative electrode using nickel (Ni) material or copper plated nickel (Ni Cu) material. In the manufacturing process of power batteries, one of the steps is to weld the battery ear and pole together. In the production of the secondary battery, it needs to be welded together with another aluminum safety valve. Welding not only requires reliable connection between the pole ear and pole, but also requires smooth and beautiful welding seams.

3. Spot welding of battery electrode strip

The materials used for battery electrode strips include pure aluminum strip, nickel strip, aluminum nickel composite strip, and a small amount of copper strip. The welding of battery electrode strips generally uses pulse welding machines. With the emergence of the QCW quasi continuous laser from IPG company, it has also been widely used in battery electrode strip welding. At the same time, due to its good beam quality and the ability to achieve very small welding spots, it has unique advantages in dealing with the welding of high reflectivity aluminum strips, copper strips, and narrow band battery electrode strips (with a width of less than 1.5mm).

4. Welding of the sealing between the power battery shell and the cover plate

The shell materials of power batteries include aluminum alloy and stainless steel, with aluminum alloy being the most commonly used, usually 3003 aluminum alloy, and a few using pure aluminum. Stainless steel is the material with the best laser weldability. Whether it is pulsed or continuous laser, welds with good appearance and performance can be obtained. By using a continuous laser to weld thin shell lithium batteries, the efficiency can be increased by 5-10 times, and the appearance and sealing performance are better. Therefore, there is a trend to gradually replace Pulsed laser in this application field.

5. Power battery module and pack welding

The series and parallel connection between the power batteries is generally completed by welding the connecting piece and the single battery. The positive and negative electrode materials are different, and generally there are two kinds of materials: copper and aluminum. Because the brittle compound formed after laser welding between copper and aluminum can not meet the use requirements, Ultrasonic welding is usually used, and copper and copper, aluminum and aluminum are generally laser welded. Meanwhile, due to the fast heat transfer of copper and aluminum, as well as their high laser reflectivity and relatively large thickness of the connecting piece, it is necessary to use a high-power laser to achieve welding.

About HGTECH

HGTECH is the pioneer and leader of laser industrial application in China, and the authoritative provider of global laser processing solutions. We comprehensively layout the construction of laser intelligent equipment, measurement and automation production lines, and smart factories to provide an overall solution for intelligent manufacturing.

We deeply grasp the development trend of manufacturing industry, constantly enrich products and solutions, adhere to exploring the integration of automation, informatization, intelligence and manufacturing industry, and provide various industries with laser cutting systems, laser welding systems, laser marking series, laser texturing complete equipment, laser heat treatment systems, laser drilling machines, lasers and various supporting devices The overall plan for the construction of special laser processing equipment and plasma cutting equipment, as well as automatic production lines and smart factories.