Preparing method for aluminum plastic film for lithium battery packaging

Abstract

The invention discloses a preparing method for an aluminum plastic film for lithium battery packaging. The method comprises the following steps that firstly, an outer layer material and a first bonding material are added in a screw A and a screw B of a two-layer co-extrusion sheet unit and are melted and co-extruded in a screw extruder to be in tape casting to one side of aluminum foil to become a film; secondly, an inner layer material and a second bonding material are added in the screw A and the screw B of the two-layer co-extrusion sheet unit and are melted and co-extruded in the screw extruder to be in tape casting to the other side of the aluminum foil to become a film; and then the aluminum plastic film for lithium battery packaging can be obtained. The outer layer material or the inner layer material is melted and co-extruded to be in tape casting to the surface of the aluminum foil to become the film in the screw extruder melting, co-extrusion and tape casting manner; the outer layer material (or the inner layer material) in the molten state and the bonding material can seep into each other among the layers, and when the outer layer material (or the inner layer material) and the bonding material are in tape casting to the surface of the aluminum foil to be laminated, interlayer bonding is firmer, and the interlayer bonding strength is further improved.

Description

technical field [0001] The invention relates to a preparation method of an aluminum-plastic film for lithium battery packaging, and relates to the technical field of aluminum-plastic film for lithium battery packaging. Background technique [0002] In recent years, with the development of polymer lithium-ion battery technology, the application of aluminum-plastic packaging film (also known as aluminum-plastic film) has become more and more extensive. Using aluminum-plastic packaging film to replace the original steel structure packaging material can effectively prevent The explosion accident caused by the high temperature and high pressure generated by the violent chemical reaction inside the battery improves the safety of lithium-ion batteries. [0003] At present, the aluminum-plastic film for lithium battery packaging in the international and domestic markets has been monopolized by Japanese companies in terms of production and technology. In recent years, many domestic c...

AI Technical Summary

Problems solved by technology

However, the above two methods have the following problems: the adhesive used in the dry composite method contains a large amount of organic solvents, which are extremely volatile and cause environmental pollution, and once the electrolyte penetrates through the inner layer material during the use of lithium batteries, strong corrosion The electrolyte will decompose the adhesive, and then corrode the aluminum foil and the outer material, causing the lithium battery to leak

However, thermal compounding requires multiple membrane material guiding devices and a complicated membrane preheating process. The process is complicated, which increases production costs and prolongs the production cycle.

In addition, whether it is dry lamination or thermal lamination, ready-made inner and outer film layers need to be purchased separately, so the production cost is relatively high

[0005] In view of the above technical problems, the Chinese invention patent CN104241556 discloses a kind of aluminum-plastic film for flexible packaging of lithium batteries produced by a new multi-layer co-extrusion casting technology. Homopolypropylene as the base material, styrene-maleic anhydride copolymer as the active monomer, and dicumyl peroxide as the additive) are extruded by a multi-screw extruder, while the outer polyester layer (PET) and The inner co-polypropylene layer (CPP) is still a pre-prepared film material, not a real multi-layer co-extrusion casting production process, see its claims 1 and 8, which includes the middle aluminum base layer, and the inner side is sequentially from the inside to the The outer distribution is a new functional adhesive resin layer (AD), polyester layer (PET), and co-polypropylene layer (CPP), and the outer side is distributed from the inside to the outside as a new functional adhesive resin layer (AD), polyester layer (PET ), homopolypropylene (PP); finally, a five-layer cast co-extrusion equipment is used for multi-layer co-aid casting process. The five layers here refer to the aluminum base layer, polyester layer (PET), and polypropylene layer. (CPP), polyester layer (PET), homopolypropylene (PP), it can be seen that these 5 layers are made of ready-made aluminum layer, inner film layer and outer film layer

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