Laser welding technology for negative pole ear and battery case of cylindrical lithium-ion battery

Abstract

The invention provides a laser welding technology for a negative pole ear and a battery case of a cylindrical lithium-ion battery. The laser welding technology is implemented by a unit comprising thebattery case, wherein a press bar is mounted on one side of the top of the battery case, a battery holder is mounted on the surface of one side of the outer wall of the battery case, a roll core is mounted in an inner cavity of the battery case, the negative pole ear is mounted on one side of the bottom of the roll core, a laser welding device is mounted on one side of the bottom of the battery case, and laser beams are emitted from the output end of the laser welding device. By means of laser welding of the negative pole ear and the battery case, the bottleneck problem of the welding processis solved, the welding is more firm and more reliable, welding intensity and welding consistency are improved, the welding process is carried out more automatically, the process and the defective rateof products are reduced, production and manufacturing cost and labor cost are reduced, and production efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a laser welding process for a cylindrical lithium-ion battery negative tab and a battery case. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long life, high charge-discharge rate, and good low-temperature performance. They are widely used in digital products, household appliances, medical equipment, passenger cars, commercial vehicles, and special power supplies. Lithium-ion batteries can be divided into cylindrical lithium-ion batteries, square lithium-ion batteries and button lithium-ion batteries according to their shape. And because the cylindrical lithium-ion battery has a very high level of automation, mature technology and high safety, its market share is also increasing. During the manufacturing process of lithium-ion batteries, the assembly process is crucial to the quality and safety of the product. Among...

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Problems solved by technology

However, its disadvantages are also very obvious: (1) As the efficiency of the cylindrical lithium-ion battery assembly line is getting higher and higher, the time left for welding a negative ear of the battery is less than 0.3 seconds, so such a short welding time is less than 0.3 seconds. It is difficult to guarantee the quality of the welding machine. If the number of welding machines is increased, the difference in welding will be increased, and the equipment maintenance cost will also increase accordingly; (2) The current negative tabs are getting thinner and thinner, and there are two negative tabs The cylindrical lithium-ion battery, and the material has also changed from nickel-copper composite or copper, which is easy to weld, so welding has become difficult; It is very easy to happen. Weak welding will cause the vibration of the battery in the normal use of the new energy vehicle, resulting in the desoldering of the negative tab and the battery case, and the battery will fail. Over-soldering may cause the battery case to leak or welding spatter will cause the internal short circuit of the battery, causing battery explosion

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