A kind of flexible packaging lithium ion battery

Abstract

The invention discloses a flexible package lithium ion battery which comprises an anode, a cathode, a diaphragm, electrolyte and an electrode terminal, wherein the anode, the cathode, the diaphragm and the electrolyte are sealed in a package film; the electrode terminal is welded with the electrode and is adhered and sealed with the package film to be led out; and the package film is a composite film formed by inner layer and outer layer macromolecule films and an inorganic oxide macromolecule plating film. A macromolecule resin layer is arranged between the contacted part of the upper lateral surface of the electrode terminal and an inner layer macromolecule film of the packaging film as well as the contacted part of the lower lateral surface of the electrode terminal and the inner layer macromolecule film of the packaging film; and the packaging film, the macromolecule resin layer and the electrode terminal are adhered and sealed by using a hot press method. Compared with the traditional aluminum-plastic film flexible package lithium ion battery, the flexible package lithium ion battery disclosed by the invention has the advantages that the electrode terminal cannot be short-circuited through the package film; the battery cannot be swollen or leak liquid due to electrochemical corrosion of the package film; and the package film has the advantages of bending resistance, torsion resistance, transparency and better microwave transmitting performance.

Description

technical field [0001] The patent of the present invention belongs to the field of lithium-ion batteries, and more specifically, the invention relates to a packaging film and a lithium-ion battery using the packaging film. Background technique [0002] Traditional flexible packaging lithium-ion batteries usually use aluminum-plastic composite film as the shell. Usually, the aluminum-plastic composite film is mainly composed of three functional layers. The middle layer is an aluminum layer, which is mainly used to block water vapor and air; the inner layer is PP. The outer layer is mainly used for heat sealing; the outer layer is nylon, which mainly plays the protective role of insulation, wear resistance, heat resistance and enhanced flexibility. For example, the invention patent application with the publication number CN101350370A discloses an aluminum-plastic composite film using PP / ethylene-methacrylic acid copolymer / aluminum foil / ethylene-methacrylic acid copolymer / PP; t...

AI Technical Summary

Problems solved by technology

The treated insulating layer not only increases the battery production process, but also the insulating coating will occupy the size space of the lithium-ion battery, which is not conducive to the improvement of the volumetric energy density of the lithium-ion battery

In addition, such cases of battery failure due to the short circuit between the electrode terminal and the aluminum foil layer also occur from time to time

[0004] (2) After the aluminum-plastic composite film is stretched, heat-sealed, and bent, it often causes damage to the corresponding parts of the heat-sealing layer, resulting in a decrease in the ionic insulation capacity of the corresponding parts

When the thin layer of aluminum foil is etched through, its function of blocking water vapor and air will be completely lost, resulting in failure of lithium-ion batteries such as swelling or leakage

Although necessary measures have been taken in the process to prevent damage to the heat-sealing layer and prevent short circuit between the negative terminal and the aluminum foil layer, they have not fundamentally solved the problem of battery failure caused by the electrochemical corrosion of the aluminum-plastic composite film.

[0005] (3) The aluminum layer in the aluminum-plastic composite film is easily broken due to metal fatigue at the corners of stretching and heat-sealed edges, thus losing its function of blocking water vapor and air, resulting in bulging of lithium-ion batteries or leakage failure

[0006] In addition, the packaging films of traditional flexible packaging lithium-ion batteries are all opaque materials, and the materials sealed in the casing and the environment inside the casing cannot be observed or tested in situ by visual or optical methods.

For example, it is impossible to detect changes in the acid-base environment inside traditional lithium-ion battery cells through pH test paper, and it is also impossible to conduct in-situ analysis of materials in the shell through optical or electron microscopes.

Images