A lithium battery aluminum-plastic packaging film using aluminum foil single-sided nano-processing technology

Abstract

An aluminum-plastic packaging film for lithium batteries using a single-sided nano-treatment process for aluminum foil. An outer film is compounded on the outer surface of the aluminum foil through an adhesive layer. The outer film is a biaxial semi-stretched PET polyester film or PET particles, Co-extruded cast film of three kinds of particles, adhesive particles and nylon particles; put the aluminum foil compounded with the outer film into the electrolyte to perform single-surface nano-treatment on the inner surface of the aluminum foil, and form a nano-anti-corrosion layer on the inner surface of the aluminum foil; Then through extrusion compounding, the inner layer of polypropylene PP is compounded outside the nano anticorrosion layer of aluminum foil; it makes single-sided chemical treatment possible, that is, reduces the amount of treatment chemicals, and at the same time does not change the traditional dry compounding process of aluminum foil, avoiding the Research and development of dry composite adhesive and curing process of nylon or PET and aluminum foil with surface chemical treatment. During the single-sided chemical treatment process, the aluminum foil is not easy to wrinkle when unwinding and unwinding, and will not produce ripples, which will not affect the compounding of the subsequent process.

Description

technical field [0001] The invention relates to a packaging film, in particular to an aluminum-plastic packaging film for a lithium battery using a single-sided nano-treatment process of aluminum foil. Background technique [0002] The inner surface of the aluminum foil in the middle layer of the aluminum-plastic composite film for flexible packaging lithium batteries needs to prevent the high fluidity, strong permeability, strong solubility and strong corrosive electrolyte in the lithium battery from destroying the high-strength adhesion between the aluminum foil and PPa, so that it Layering, thereby greatly reducing the internal and external high barrier properties of the lithium battery packaging film, and the surface of the aluminum foil bonded to the PPa must be treated with nano-anticorrosion. [0003] The products of this project have been monopolized by DNP and Showa Denko in Japan for 15 years, and 100% of them are imported from China. One of the technical difficult...

AI Technical Summary

Problems solved by technology

There is no ready-made equipment for this process, and even if the order is entrusted to Japan, the price is very expensive, and it is difficult to have this kind of manufacturing capacity in China. This is one of the reasons that has restricted the localization of this project in the past 15 years.

2. Judging from the structure of the lithium battery flexible packaging film, nylon has been used as the outermost surface for many years, and nylon is very easy to absorb water. In addition to surface adhesion, the water is also very easy to form bound water. The nano-treatment liquid on the surface of aluminum foil is water often Solvent, the oven during the treatment process cannot dry the moisture, especially the bound water, and the moisture will be partially transferred to the PP surface where the inner layer of the aluminum-plastic film of the lithium battery that has been in contact with it for a long time will be in direct contact with the electrolyte. Hydrofluoric acid makes the battery swell, and will also penetrate into the inner surface of the aluminum-plastic film aluminum foil with the organic solvent, corrode the aluminum foil, thereby destroying the adhesive layer, delaminating the PP layer and the aluminum foil, which will accelerate the leakage of the electrolyte inside the lithium battery and external air penetrate into the battery, making the lithium battery function rapidly invalid