A laser precision welding method for edge sealing of soft-clad aluminum shell cells

Abstract

The invention provides a laser precision welding method for edge sealing of soft-clad aluminum-shell electric cores, which includes: two electric cores to be edge-sealed and welded with soft-wrapped aluminum-plastic composite films according to the edge-sealing welding position, so that the PP inner layer is relatively attached to each other. Put it together; add a transparent glass layer on the upper nylon layer, and fill a thin layer of cooling liquid to isolate the two; apply pressure to make the layers contact closely; use the laser beam to incident from above the transparent glass layer, and the laser beam is focused on the upper The surface of the aluminum layer melts the upper PP layer and the lower PP layer; stop the irradiation or remove the laser beam, and the melted upper PP layer and lower PP layer cool down rapidly and solidify to achieve a firm and tight sealing edge. The invention utilizes the laser absorption, rapid temperature rise and heat conduction of the middle layer of aluminum foil to realize the technological effect of melting the PP layer but not melting the nylon outer layer, and realizes the laser precision of the upper and lower aluminum-plastic composite film PP inner layers under the action of external pressure. welding. The laser precision welding has the advantages of narrow edge width, good sealing quality and high production efficiency.

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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