阅读说明：本技术 一种锂离子电池封装用铝塑复合膜 (Aluminum-plastic composite film for packaging lithium ion battery ) 是由 程跃 陈滨 王小明 于 2019-09-24 设计创作，主要内容包括：本发明涉及一种锂离子电池封装用铝塑复合膜,该铝塑复合膜从外到内依次由保护层、第一胶黏剂层、第一防腐处理层、铝箔层、第二防腐处理层、第二胶黏剂层和三层流延聚丙烯层(CPP)组成。成品铝箔经过超声波中酸液脱脂、碱液腐蚀、电晕化处理后,水在铝箔暗面60s的接触角为10°～35°之间,水在铝箔亮面60s的接触角为15°～45°,铝箔两面再分别经过钝化防腐处理后,水在铝箔暗面60s的接触角变化范围在10°以内,水在铝箔亮面60s的接触角变化在15°以内。铝箔通过超声波中酸液脱脂、碱液腐蚀和电晕化处理后,增加了铝箔上涂布钝化液的流平性,间接提高了铝塑复合膜中铝箔与CPP层间的粘结强度,也提高复合膜的耐电解液性能。(The invention relates to an aluminum-plastic composite film for packaging a lithium ion battery, which sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and three cast polypropylene layers (CPP) from outside to inside. After the finished aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, the contact angle of water on the dark surface 60s of the aluminum foil is between 10 and 35 degrees, the contact angle of water on the bright surface 60s of the aluminum foil is between 15 and 45 degrees, after the two surfaces of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the contact angle of water on the dark surface 60s of the aluminum foil is within 10 degrees, and the change of the contact angle of water on the bright surface 60s of the aluminum foil is within 15 degrees. After the aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, the leveling property of the passivation solution coated on the aluminum foil is improved, the bonding strength between the aluminum foil and a CPP layer in the aluminum-plastic composite film is indirectly improved, and the electrolyte resistance of the composite film is also improved.)

1. The aluminum-plastic composite film for packaging the lithium ion battery is characterized by at least comprising an aluminum foil layer;

the contact angle of water on the dark surface of the aluminum foil in the aluminum foil layer for 60s is between 10 and 35 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is between 15 and 45 degrees;

after the two sides of the aluminum foil layer are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees.

2. The aluminum-plastic composite film for lithium ion battery packaging according to claim 1, wherein the aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 0.5-2%, and the thickness of the aluminum foil is 25-60 μm.

3. The aluminum-plastic composite film for packaging a lithium ion battery according to claim 1, wherein the aluminum foil in the aluminum-plastic composite film is subjected to degreasing by an acid solution in ultrasonic waves, corrosion by an alkali solution, corona treatment, and passivation by a passivation solution.

4. The aluminum-plastic composite film for packaging the lithium ion battery as claimed in claim 1, wherein the aluminum-plastic composite film comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer CPP in sequence from outside to inside.

5. The aluminum-plastic composite film for packaging the lithium ion battery according to claim 4, wherein the protective layer is formed by compounding or co-extruding one or more of polyamide, polyester, polyurethane, polyimide and acrylic resin materials, and the total thickness of the protective layer is 15-35 microns.

6. The aluminum-plastic composite film for packaging the lithium ion battery according to claim 4, wherein the protective layer and the aluminum foil are bonded through a first adhesive layer, the first adhesive is polyurethane and derivatives thereof, and the thickness of the first adhesive film layer is 1-5 microns.

7. The aluminum-plastic composite film for packaging the lithium ion battery according to claim 4, wherein the CPP layer and the aluminum foil layer are bonded by a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of the second adhesive film layer is 2-20 micrometers.

8. The aluminum-plastic composite film for packaging the lithium ion battery as claimed in claim 4, wherein the CPP layer is one or more of random, copolymerization, block polypropylene, homo-polypropylene and polyolefin elastomer materials, and is formed by adopting a casting co-extrusion process, and the total thickness of the CPP film layer is 35-80 microns.

Technical Field

The invention relates to the technical field of aluminum-plastic films, in particular to an aluminum-plastic composite film for packaging a lithium ion battery.

Background

The lithium ion battery flexible package is a packaging mode which is more and more widely applied, and the main structure of the lithium ion battery flexible package is formed by compounding three layers of film materials, namely a protective layer, an aluminum foil layer and a heat sealing layer from outside to inside. Lithium ion battery's electrolyte contains multiple organic solvent and lithium salt, and the lithium salt meets water can produce the hydrofluoric acid of strong corrosivity rapidly, and the hydrofluoric acid of production can slowly corrode infiltration CPP layer, further can destroy aluminium foil and CPP complex gluing agent layer in the plastic-aluminum composite membrane, finally destroys the aluminium foil surface, if the passivation corrosion resistant layer on aluminium foil surface is even compact inadequately, can cause the problem such as lithium cell layering, weeping inefficacy finally.

At present, flaws such as oil stains on the surface of a product of an aluminum foil leaving a factory are not well controlled, if the aluminum foil is used for passivation treatment, a uniform and compact corrosion-resistant protective layer is difficult to obtain on the surface of the aluminum foil, a passivated aluminum foil composite protective layer and a CPP layer are also in great risk of composite falling of the aluminum foil and an inner layer and an outer layer, and particularly, electrolyte resistance of an aluminum-plastic composite film is generally influenced by an aluminum-plastic composite film finished product subjected to deep drawing forming.

Disclosure of Invention

The invention aims to overcome the defect of poor surface treatment of an aluminum foil used in the existing aluminum-plastic composite film, and aims to provide the aluminum foil with no greasy dirt on the surface and good surface wettability.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the utility model provides a lithium ion battery encapsulates uses plastic-aluminum complex film which characterized in that: the aluminum-plastic composite film at least comprises an aluminum foil layer;

the contact angle of water on the dark surface of the aluminum foil in the aluminum foil layer for 60s is between 10 and 35 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is between 15 and 45 degrees;

after the two sides of the aluminum foil layer are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees.

As a preferred technical scheme: an outer packaging material for a lithium ion battery, characterized in that:

the aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

preferably, the aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 0.5-2%, and the thickness of the aluminum foil is 25-60 microns;

preferably, the aluminum foil is subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, and then passivation treatment is performed by using a passivation solution;

preferably, acid liquor degreasing in aluminum foil ultrasonic wave means that the aluminum foil is immersed in a tank filled with solvents such as sulfuric acid, phosphoric acid and surfactants for 10-20 s under the action of the ultrasonic wave, the temperature is 40-60 ℃, surface oil stains are removed, the frequency of the ultrasonic wave is more than 16KHz, and the degreasing effect and speed are promoted;

preferably, the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acid degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 30-60 s at the temperature of 45-65 ℃, an oxidation film on the surface of the aluminum foil is removed, and the surface of the aluminum foil is activated;

preferably, the corona treatment of the aluminum foil means that the aluminum foil corroded by the alkali liquor needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer, so that the surface roughness is increased, the surface of the aluminum foil is activated and polarized, and the adhesion with a polar solvent is increased;

preferably, a passivation solution is coated on the two sides of the aluminum foil subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, passivation and corrosion prevention treatment is carried out, the main components of the passivation solution are trivalent chromate, phosphate, acrylic resin and the like, and the passivation solution is treated at the baking temperature of 180-220 ℃ for 1-5 s;

preferably, the passivated dark surface and the passivated bright surface of the aluminum foil are respectively coated with a first adhesive and a second adhesive, and then a protective layer and a CPP layer are compounded;

preferably, the protective layer is formed by compounding or co-extruding one or more of polyamide, polyester, polyurethane, polyimide, acrylic resin and the like, and the total thickness of the protective layer is 15-35 microns;

preferably, the first adhesive is polyurethane and derivatives thereof, and the thickness of the first adhesive film layer is 1-5 micrometers;

preferably, the CPP layer and the aluminum foil layer are bonded through a second adhesive by a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of the second adhesive film layer is 2-20 micrometers;

preferably, the CPP layer is formed by one or more of random, copolymerization, block polypropylene, homo-polypropylene, polyolefin elastomer and other materials by adopting a casting co-extrusion process, and the total thickness of the CPP film layer is 35-80 microns. By adopting the technical scheme, the invention has obvious advantages compared with the prior art. Specifically, the surface of the aluminum foil before passivation is free of oil stains and excellent in wettability, so that the passivation anti-corrosion treatment layer is uniform and compact, the composite bonding strength of the passivated aluminum foil and the CPP layer is favorably enhanced, and the electrolyte resistance of the aluminum-plastic composite film is favorably improved.

In order to more clearly illustrate the structural features, technical means and functions achieved by the present invention, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments:

drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention.

The attached drawings indicate the following:

1 a nylon layer, wherein the nylon layer is a nylon layer,

2 a first adhesive layer, a second adhesive layer,

3, a passivation anticorrosive layer is arranged on the dark side,

4 a layer of aluminium foil having a high tensile strength,

5 a bright surface passivation anti-corrosion layer,

6 a second adhesive layer, wherein the second adhesive layer,

7CPP layer.

Detailed Description

Example 1

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

the aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, and then passivation treatment is carried out by using a passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 20s under the action of the ultrasonic wave, wherein the temperature is 50 ℃, and the ultrasonic frequency is more than 16 KHz;

the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acidic degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 55s at the temperature of 55 ℃;

the corona treatment of the aluminum foil means that the aluminum foil after being corroded by alkali liquor needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves is 10 degrees, and the contact angle of water on the bright surface of the aluminum foil is 15 degrees for 60 s;

coating passivation solution on the two sides of the aluminum foil subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, and performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate and is treated at the baking temperature of 200 ℃ for 3 s;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyamide material, and the thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Example 2

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

the aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, and then passivation treatment is carried out by using a passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 20s under the action of the ultrasonic wave, wherein the temperature is 50 ℃, and the ultrasonic frequency is more than 16 KHz;

the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acidic degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 40s at the temperature of 55 ℃;

the corona treatment of the aluminum foil means that the aluminum foil after being corroded by alkali liquor needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves for 60s is 18 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is 22 degrees;

coating passivation solution on the two sides of the aluminum foil subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, and performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate and is treated at the baking temperature of 200 ℃ for 3 s;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyester material, and the thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Example 3

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

the aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, and then passivation treatment is carried out by using a passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 15s under the action of the ultrasonic wave, wherein the temperature is 55 ℃, and the ultrasonic frequency is more than 16 KHz;

the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acidic degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 50s at the temperature of 55 ℃;

the corona treatment of the aluminum foil means that the aluminum foil after being corroded by alkali liquor needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves is 22 degrees, and the contact angle of water on the bright surface of the aluminum foil is 25 degrees for 60 s;

coating passivation solution on the two sides of the aluminum foil subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, and performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate and is treated at the baking temperature of 200 ℃ for 3 s;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is a composite material of polyamide and polyester, and the total thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Example 4

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

the aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, and then passivation treatment is carried out by using a passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 20s under the action of the ultrasonic wave, wherein the temperature is 55 ℃, and the ultrasonic frequency is more than 16 KHz;

the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acidic degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 35s at the temperature of 55 ℃;

the corona treatment of the aluminum foil means that the aluminum foil after being corroded by alkali liquor needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves is 28 degrees, and the contact angle of water on the bright surface of the aluminum foil is 30 degrees for 60 s;

coating passivation solution on the two sides of the aluminum foil subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, and performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate and is treated at the baking temperature of 200 ℃ for 3 s; after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees; respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyimide material, and the total thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Example 5

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

the aluminum foil is subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves, and then passivation treatment is carried out by using a passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 10s under the action of the ultrasonic wave, wherein the temperature is 40 ℃, and the ultrasonic frequency is more than 16 KHz;

the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acidic degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 30s at the temperature of 45 ℃;

the corona treatment of the aluminum foil means that the aluminum foil after being corroded by alkali liquor needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil subjected to acid liquid degreasing, alkali liquid corrosion and corona treatment in ultrasonic waves for 60s is 35 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is 45 degrees;

coating passivation solution on the two sides of the aluminum foil subjected to acid liquid degreasing in ultrasonic waves, alkali liquid corrosion and corona treatment, and performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate and is treated at the baking temperature of 200 ℃ for 3 s;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 10 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 15 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyamide material, and the total thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Comparative example 1

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil for 60s is 75 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is 76 degrees;

coating passivation solution on two sides of the aluminum foil, performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate, and treating for 3s at the baking temperature of 200 ℃;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 5 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 10 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyamide material, and the thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Comparative example 2

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

the aluminum foil is subjected to acid liquid degreasing and alkali liquid corrosion in ultrasonic wave, and then passivation treatment is carried out by using a passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 20s under the action of the ultrasonic wave, wherein the temperature is 50 ℃, and the ultrasonic frequency is more than 16 KHz;

the alkaline corrosion of the aluminum foil means that the aluminum foil subjected to the acidic degreasing treatment is immersed in a tank containing alkaline liquor such as sodium hydroxide and sodium citrate for 55s at the temperature of 55 ℃;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil for 60s is 42 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is 50 degrees;

coating passivation solution on two sides of the aluminum foil, performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate, and treating for 3s at the baking temperature of 200 ℃;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 5 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 10 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyamide material, and the thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Comparative example 3

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

degreasing the aluminum foil by using acid liquor in ultrasonic waves, and then passivating the aluminum foil by using passivation solution;

degreasing the aluminum foil with acid liquor in ultrasonic wave refers to immersing the aluminum foil in a tank filled with mixed solvents of sulfuric acid, phosphoric acid, surfactant and the like (the mass ratio of the sulfuric acid to the phosphoric acid to the surfactant is 10:30:1) for 20s under the action of the ultrasonic wave, wherein the temperature is 50 ℃, and the ultrasonic frequency is more than 16 KHz;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil for 60s is 49 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is 53 degrees;

coating passivation solution on two sides of the aluminum foil, performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate, and treating for 3s at the baking temperature of 200 ℃;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 5 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 10 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyamide material, and the total thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

Comparative example 4

The aluminum-plastic composite film sequentially comprises a protective layer, a first adhesive layer, a first anticorrosion treatment layer, an aluminum foil layer, a second anticorrosion treatment layer, a second adhesive layer and a three-layer cast polypropylene layer (CPP) from outside to inside;

the selected aluminum foil is soft aluminum in a single 0 state, the iron content in the aluminum foil is 1.4%, and the thickness of the aluminum foil is 40 microns;

firstly, carrying out corona treatment on the aluminum foil, and then carrying out passivation treatment by using a passivation solution;

the corona treatment of the aluminum foil means that the aluminum foil needs to be subjected to corona treatment before being compounded with the protective layer or the CPP layer;

measuring a contact angle of the surface of the aluminum foil by using a contact angle tester, wherein a solvent is deionized water, the extrusion amount of the solvent is 2 mu L, and a recording time point is 60 s;

the contact angle of water on the dark surface of the aluminum foil for 60s is 59 degrees, and the contact angle of water on the bright surface of the aluminum foil for 60s is 62 degrees;

coating passivation solution on two sides of the aluminum foil, performing passivation and corrosion prevention treatment, wherein the main component of the passivation solution is strong-acid trivalent chromate, and treating for 3s at the baking temperature of 200 ℃;

after the two sides of the aluminum foil are respectively subjected to passivation and corrosion prevention treatment, the change range of the 60s contact angle of water on the dark side of the aluminum foil is within 5 degrees, and the change range of the 60s contact angle of water on the bright side of the aluminum foil is within 10 degrees;

respectively coating a first adhesive and a second adhesive on the passivated dark surface and the passivated bright surface of the aluminum foil, and then compounding a protective layer and a CPP layer;

the protective layer is made of polyamide material, and the total thickness of the protective layer is 25 micrometers;

the first adhesive is a polyurethane material, and the thickness of a first adhesive film layer is 3 micrometers;

the CPP layer and the aluminum foil layer are formed by bonding a second adhesive through a coating or hot extrusion process, the second adhesive layer is made of an anhydride modified polyolefin material, and the thickness of a second adhesive film layer is 4 micrometers;

the two surface layers in the CPP are made of random polypropylene as a substrate, the middle layer is made of homopolymerized polypropylene as a substrate, a tape casting co-extrusion process is adopted, and the thickness ratio of each layer is 1: 3: 1, the total thickness of the CPP film layer is 40 mu m.

The aluminum-plastic composite film samples of examples 1 to 5 and comparative examples 1 to 4 were subjected to initial peeling between aluminum foil and CPP and electrolyte resistance test at 85 ℃ using an Shimadzu electronic universal tester. The initial peeling test refers to T-peeling of a sample of the aluminum-plastic composite film 15mm wide and 100mm long. The 85 ℃ electrolyte resistance test refers to that a 15mm wide and 100mm long aluminum-plastic composite film sample is put into a container filled with electrolyte (LiPF) in a natural straightening state₆(1mol/L)/EC + PC + DMC (volume ratio is 1:1:1)) for 7 days, taking out a sample, washing with water, wiping dry, and carrying out T-type stripping, wherein the mass ratio of deionized water in the electrolyte is 1000 PPM. The test results are shown in the table:

in conclusion, as can be seen from the contact angle of the bright surface of the aluminum foil, the initial peeling between the aluminum foil and the CPP of the aluminum-plastic composite film and the electrolyte resistance test result at 85 ℃, the unpassivated aluminum foil subjected to the ultrasonic degreasing, the alkali corrosion and the corona treatment has no oil stain on the surface and excellent wettability, so that the passivated anti-corrosion treatment layer is uniform and compact, the composite bonding strength of the passivated aluminum foil and the CPP layer is enhanced, and the electrolyte resistance of the aluminum-plastic composite film is improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the concept of the present invention, and these modifications and decorations should also be regarded as being within the protection scope of the present invention.