Laser precision welding method for edge sealing of soft-package aluminum shell battery cell

Abstract

The invention provides a laser precision welding method for edge sealing of a soft-package aluminum shell battery cell. The method comprises the steps as follows: two to-be-sealed and welded battery cell soft-package aluminum-plastic composite membranes are placed in a manner that PP inner layers are oppositely laminated according to an edge sealing and welding position; a transparent glass layer is added to an upper nylon layer; the gap between the upper nylon layer and the transparent glass layer is filled with a thin-layer cooling liquid to isolate the transparent glass layer from the upper nylon layer; pressure is exerted, so that various layers are in tight contact; a laser beam is utilized to enter from the upper part of the transparent glass layer and is focused on the surface of an upper aluminum layer, so that an upper PP layer and a lower PP layer are melted; irradiation is stopped or the laser beam is moved away; and the melted upper PP layer and lower PP layer are quickly cooled and condensed to achieve firm and tight edge sealing. By laser absorption, fast heating and heat conduction of aluminum foil middle layers, the process effect that the PP layers are melted while nylon outer layers are not melted is achieved; and laser precision welding of the PP inner layers of the upper and lower aluminum-plastic composite membranes is achieved under the added pressure-assisted action. The laser precision welding method has the advantages of small edge sealing width, good sealing quality, high production efficiency and the like.

Description

technical field [0001] The invention belongs to the field of laser precision machining, and in particular relates to a laser precision welding method for edge sealing of soft-clad aluminum shell electric cores. Background technique [0002] At present, lithium-ion batteries are more and more widely used, and can be roughly divided into three categories based on the packaging shell, 18650 cylindrical batteries with cylindrical stainless steel, square batteries with aluminum shells and stainless steel shells, and soft packs with aluminum-plastic films. Battery. Lithium batteries in aluminum-plastic flexible packaging are different from the metal casing of traditional liquid batteries. Once a safety hazard occurs, traditional liquid batteries are prone to explosion, while polymer batteries will only inflate at most and will not cause any harm to personal and property safety. question. The reason is that the aluminum-plastic film of the soft bag has a certain degree of ductili...

AI Technical Summary

Problems solved by technology

However, during the sealing process of the soft package, the existing sealing machine is easy to cause air bubbles to appear at the sealing of the soft package, resulting in a decrease in the sealing performance of the soft package and affecting the service life of the soft package lithium battery; secondly, the existing sealing machine seals the soft package during the sealing process of the soft package Burrs are prone to appear at the soft package lithium battery, which will affect the bonding of the soft package seal and affect its sealing while affecting the appearance of the soft package lithium battery; moreover, the thermocompression welding method relies on slow temperature rise and pressure heat sealing, the production process is long, and Due to long-term high-temperature baking, the aluminum layer is embrittled, resulting in deterioration of sealing performance

Finally, the existing sealing machine is limited by the size of the knife-shaped indenter and the above-mentioned edge-sealing welding problem. Generally, the width of the edge-sealing is designed to be relatively large, which occupies a part of the soft-packed aluminum shell battery in the case of the same area of ​​the soft-packed battery. the internal capacity of the core, resulting in a loss of capacity

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