Lithium-ion battery laser welding sealing technology

Abstract

The invention relates to a laser beam welding and sealing technology for Li-ion battery, which realizes consecutive sealing weld to the battery shell and the battery cover of a Li-ion battery using a laser welder with 600 Hz to 20 KHz of output frequency. The laser beam welding and sealing technology for Li-ion battery of the invention carries out a consecutive sealing weld on the Li-ion battery by means of continuous output of laser energy or high frequency of the laser welder. The welding way can maintain the melting state of a welding seem all the time and push forward. The welding has the advantages of good welding effect as well as smooth and beautiful appearance; furthermore, the nugget zone in the welding centre is completely melted during welding; therefore, after cooling, the residual inter-stress of the welding joint is weak and bad phenomena such as cracking is avoided.

Description

【Technical field】 [0001] The invention relates to a lithium ion battery sealing process, in particular to a lithium ion battery continuous laser welding sealing process. 【Background technique】 [0002] The traditional lithium-ion battery laser welding seal adopts the solid pulse laser welding method. The solid pulse laser welding method is essentially spot welding, and each welding spot has 60% to 90% overlap. In this way, the multi-point overlapping method finally realizes line welding. . In traditional welding equipment, the highest pulse frequency is generally 50 Hz, and the welding speed is 6-8 mm / s. The shape of the molten pool formed by the spot welding is a parabolic shape with a large top and a small bottom. In the case of multiple spot welding overlapping, the penetration depth of the weld seam will be uneven. [0003] Moreover, pulse welding belongs to heat conduction welding. The laser is irradiated on the aluminum shell of the battery shell to heat up the surfa...

AI Technical Summary

Problems solved by technology

Using this welding method, most of the laser energy is reflected by the surface of the battery aluminum shell, the welding depth is not deep, and the utilization rate of laser energy is low.

At the same time, in the traditional solid-state pulse laser welding of lithium-ion batteries, the appearance of the weld is a straight line formed by a series of overlapping concentric rings. This weld has an unsightly appearance and a breakdown phenomenon caused by unstable pulse energy.

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