Lithium-ion batteries have the advantages of high specific energy, long cycle life, small self-discharge, no memory effect, no pollution, etc., widely used in a variety of electronic equipment (such as cell phones, notebook computers, pda, digital cameras and digital cameras, etc.) and vehicles (patrol cars, electric bicycles, electric cars, etc.),battery pilot line and has become a key focus of China's energy sector to support high-tech industries.

Power battery refers to the battery used in electric vehicles. Compared with small-capacity batteries (such as cell phones, laptop batteries), they have greater capacity and output power, and can be used as secondary batteries for electric vehicle drive power, large mobile power and other applications. There are many manufacturing processes for lithium-ion batteries or battery packs, of which laser welding is the best process for many of them, such as explosion-proof valve sealing welding, pole lug welding, flexible connection welding, helmet spot welding, battery shell sealing welding, module and group welding.laser welding machine for lithium ion batteries The welding materials for power battery are mainly pure copper, aluminum, aluminum alloy and stainless steel.

1.Battery explosion-proof valve welding

Battery explosion-proof valve is a thin-walled valve body on the battery sealing plate, when the internal pressure of the battery has exceeded the prescribed value, the explosion-proof valve body rupture, to avoid battery burst. The safety valve structure is cleverly designed, this process of laser welding production process development requirements we are extremely strict.ESS lithium battery machine No system adopts a continuous laser welding before, the battery explosion-proof valve welding process are required to use different pulse laser welding, through the welding point and welding point overlap and cover to realize the continuous sealing welding, but the level of welding management efficiency is low, and the sealing is relatively poor. The use of continuous laser welding process can effectively realize the economic high-speed high-quality welding, welding stability, welding efficiency issues and yield rate can be social security.

2. Battery ear welding

Ear usually consists of three materials: positive pole aluminum, negative pole for nickel or copper nickel plating. One step in the manufacturing process of a power battery is to weld the lugs and electrodes together. The secondary battery needs to be welded to another aluminum safety valve. Welding not only to ensure a reliable connection between the electrode lugs and electrodes, but also requires a smooth and beautiful weld seam.

3. Battery pole belt spot welding

Battery pole with the use of materials such as pure aluminum, nickel, aluminum and nickel composite tape and a small amount of copper tape. Pulse welder is generally used for battery pole piece welding. With the emergence of quasi-continuous lasers, it has been widely used in the welding of battery pole pieces. At the same time, when dealing with the welding of aluminum strip, copper strip and narrow strip battery pole strip with high reflectivity, it has a unique advantage due to its good beam quality and small welding spot.

4. Power battery shell and cover seal welding

Power battery shell materials include aluminum alloy and stainless steel, of which the most commonly used is aluminum alloy, generally 3003 aluminum alloy, a few are pure aluminum. Stainless steel is the best material for laser weldability, especially 304 stainless steel. Both pulsed and continuous lasers can obtain welds with good appearance and performance. Depending on the welding method, the welding properties of aluminum and aluminum alloy are slightly different.

5. Power battery module and pack welding

The series-parallel connection between power batteries is usually accomplished by welding the connectors and individual batteries. The materials of positive and negative electrodes are different, generally there are two kinds of materials: copper and aluminum. Because the brittle compounds formed by copper and aluminum after laser welding can not meet the requirements of use, ultrasonic welding is usually used, and copper and copper, aluminum and aluminum are generally laser welded. At the same time, because both copper and aluminum heat transfer rate is very fast, the laser reflectivity is very high, the thickness of the connector is relatively large, so it is necessary to use a larger power of the laser to achieve the welding.