阅读说明：本技术 一种锂电池软包装膜用铝箔的处理方法 (Treatment method of aluminum foil for lithium battery flexible packaging film ) 是由 吕松 于 2019-10-21 设计创作，主要内容包括：本发明涉及电池包装膜技术领域,尤其是一种锂电池软包装膜用铝箔的处理方法,包括以下步骤：(1)预处理：将厚度为20-60μm的铝合金作为基底置于碱液中进行预处理,30-60℃浸泡1-10min,然后用去离子水冲洗干净；(2)凿孔：将步骤(1)中预处理后得到的基底置于凿孔液中进行凿孔处理,30-60℃浸泡1-5min,然后用去离子水冲洗干净；(3)钝化处理；(4)表面修饰处理；本发明中采用三乙醇胺作为铝箔的钝化处理液,三乙醇胺具有弱碱性,高纯铝箔浸入处理液后,表面发生碱式溶解,在铝箔表面形成一水合软铝石沉积膜,沉积膜可以阻止内部的高纯铝进一步碱式溶解,然后高温处理,提高氧化膜中γ-氧化铝的含量,避免使用铬液作为钝化剂,造成环境污染的不足。(the invention relates to the technical field of battery packaging films, in particular to a method for processing an aluminum foil for a lithium battery flexible packaging film, which comprises the following steps: (1) pretreatment: taking an aluminum alloy with the thickness of 20-60 mu m as a substrate, putting the aluminum alloy in an alkali liquor for pretreatment, soaking for 1-10min at the temperature of 30-60 ℃, and then washing the aluminum alloy clean by deionized water; (2) drilling holes: placing the substrate obtained after pretreatment in the step (1) in a punching liquid for punching, soaking for 1-5min at 30-60 ℃, and then washing with deionized water; (3) passivating; (4) surface modification treatment; according to the invention, triethanolamine is used as a passivation treatment solution of the aluminum foil, the triethanolamine has alkalescence, after the high-purity aluminum foil is immersed in the treatment solution, the surface of the aluminum foil is subjected to alkaline dissolution, a boehmite deposition film is formed on the surface of the aluminum foil, the deposition film can prevent the high-purity aluminum in the aluminum foil from further alkaline dissolution, and then the aluminum foil is treated at high temperature, so that the content of gamma-alumina in an oxide film is increased, and the defect of environmental pollution caused by using a chromium solution as a passivating agent is avoided.)

1. A processing method of aluminum foil for lithium battery flexible packaging film is characterized by comprising the following steps: the processing method comprises the following steps:

(1) pretreatment: taking an aluminum alloy with the thickness of 20-60 mu m as a substrate, putting the aluminum alloy in an alkali liquor for pretreatment, soaking for 1-10min at the temperature of 30-60 ℃, and then washing the aluminum alloy clean by deionized water;

(2) drilling holes: placing the substrate obtained after pretreatment in the step (1) in a punching liquid for punching, soaking for 1-5min at 30-60 ℃, then washing with deionized water, and drying;

(3) passivating: coating passivation treatment liquid on one side surface of the substrate, wherein the passivation treatment liquid is triethanolamine solution, the coating temperature is 76-80 ℃, standing for 8min after coating, and then drying;

(4) surface modification treatment: and (4) placing the substrate treated in the step (3) in surface modification liquid for modification treatment, soaking for 1-5min, and washing and drying with deionized water to obtain the aluminum foil for the flexible packaging film with the compact oxide film layer on the surface.

2. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: the alkali liquor in the step (1) is a mixed solution of sodium carbonate and sodium hydroxide, wherein the concentration of the sodium carbonate is 0.5-1.8 mol/l, and the concentration of the sodium hydroxide in the mixed solution is 0.2-2.5 mol/l.

3. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: the punching liquid in the step (2) is a mixed solution of amino acid, sodium oxalate and sodium hydroxide, and the pH value of the punching liquid is 8.5-9.2.

4. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 3, wherein the method comprises the following steps: in the mixed solution, the addition amount of amino acid is 50 parts by mass, the addition amount of sodium oxalate is 10-100 parts by mass, and the addition amount of sodium hydroxide is 30-500 parts by mass.

5. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: the concentration of the passivation treating solution in the step (3) is 1.8ml/l of triethanolamine solution.

6. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: the drying temperature in the step (3) is 550-580 ℃, and the drying time is 2-3 min.

7. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: the coating weight is 0.02-0.35g/m 2.

8. The method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: the surface modification solution in the step (4) is a tannic acid solution, and the concentration of the tannic acid solution is 2-6 mol/l.

9. the method for treating the aluminum foil for the lithium battery flexible packaging film according to claim 1, wherein the method comprises the following steps: in the step (4), the soaking temperature is 40-80 ℃, the soaking time is 30-120s, and the drying temperature is 80-120 ℃.

Technical Field

The invention relates to the technical field of battery packaging films, in particular to a method for processing an aluminum foil for a lithium battery flexible packaging film.

background

The packaging of lithium ion batteries is divided into two categories, one is a soft package battery cell and the other is a metal shell battery cell. The metal shell battery core comprises a steel shell, an aluminum shell, a cylinder, a square and the like.

The packaging material and the structure of the soft package battery enable the soft package battery to have a series of advantages, for example, the safety performance is good, the soft package battery is packaged by an aluminum plastic film structurally, and when safety problems occur, the soft package battery generally can be blown and cracked, and explosion is not caused like a steel shell or an aluminum shell battery cell; the weight of the soft package battery is 40% lighter than that of a steel shell lithium battery with the same capacity, and is 20% lighter than that of an aluminum shell lithium battery; the internal resistance is small, the internal resistance of the soft package battery is smaller than that of a lithium battery, and the self power consumption of the battery can be greatly reduced; the cycle performance is good, the cycle life of the soft package battery is longer, and the cycle attenuation of 100 times is 4-7% less than that of an aluminum shell; the design is flexible, the appearance can be changed into any shape, the thickness can be thinner, and the novel battery cell model can be developed according to the customization of the requirements of customers.

The aluminum plastic film generally has three layers, namely a nylon layer, a metal aluminum foil layer and a polypropylene layer, and generally performs surface passivation treatment on the surface of a metal aluminum foil to form a compact oxide film.

disclosure of Invention

The purpose of the invention is: overcomes the defects in the prior art, and provides a method for treating the aluminum foil for the lithium battery flexible packaging film, which has simple process and environment-friendly and pollution-free passivator.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

A treatment method of an aluminum foil for a lithium battery flexible packaging film comprises the following steps:

(1) Pretreatment: taking an aluminum alloy with the thickness of 20-60 mu m as a substrate, putting the aluminum alloy in an alkali liquor for pretreatment, soaking for 1-10min at the temperature of 30-60 ℃, and then washing the aluminum alloy clean by deionized water;

(2) drilling holes: placing the substrate obtained after pretreatment in the step (1) in a punching liquid for punching, soaking for 1-5min at 30-60 ℃, then washing with deionized water, and drying;

(3) Passivating: coating passivation treatment liquid on one side surface of the substrate, wherein the passivation treatment liquid is triethanolamine solution, the coating temperature is 76-80 ℃, standing for 8min after coating, and then drying;

(4) surface modification treatment: and (4) placing the substrate treated in the step (3) in surface modification liquid for modification treatment, soaking for 1-5min, and washing and drying with deionized water to obtain the aluminum foil for the flexible packaging film with the compact oxide film layer on the surface.

Further, the alkali liquor in the step (1) is a mixed solution of sodium carbonate and sodium hydroxide, wherein the concentration of the sodium carbonate is 0.5-1.8 mol/l, and the concentration of the sodium hydroxide in the mixed solution is 0.2-2.5 mol/l.

further, the punching liquid in the step (2) is a mixed solution of amino acid, sodium oxalate and sodium hydroxide, and the pH value of the punching liquid is 8.5-9.2.

Furthermore, in the mixed solution, the addition amount of amino acid is 50 parts by mass, the addition amount of sodium oxalate is 10-100 parts by mass, and the addition amount of sodium hydroxide is 30-500 parts by mass.

further, the concentration of the passivation treating solution in the step (3) is 1.8ml/l, wherein the concentration of the solution is triethanolamine solution.

Further, the drying temperature in the step (3) is 550-.

Further, the coating amount is 0.02 to 0.35g/m 2.

further, the surface modification solution in the step (4) is a tannic acid solution, and the concentration of the tannic acid solution is 2-6 mol/l.

Further, in the step (4), the soaking temperature is 40-80 ℃, the soaking time is 30-120s, and the drying temperature is 80-120 ℃.

The technical scheme adopted by the invention has the beneficial effects that:

According to the invention, triethanolamine is used as a passivation treatment solution of the aluminum foil, the triethanolamine has alkalescence, after the high-purity aluminum foil is immersed in the treatment solution, the surface of the aluminum foil is subjected to alkaline dissolution, a boehmite deposition film is formed on the surface of the aluminum foil, the deposition film can prevent the high-purity aluminum in the aluminum foil from further alkaline dissolution, and then the aluminum foil is subjected to high-temperature treatment, so that the content of gamma-alumina in an oxide film is increased, and the defect of environmental pollution caused by using a chromium solution as a passivating agent is avoided.

According to the invention, a mixed solution of amino acid, sodium oxalate and sodium hydroxide is used as a punching liquid, and punching treatment is carried out on the aluminum foil before passivation treatment, so that a passivation layer can be formed on the surface of the aluminum foil at a later stage.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments in order to make the above objects, features and advantages more apparent and understandable.

A treatment method of an aluminum foil for a lithium battery flexible packaging film comprises the following steps:

(1) pretreatment: taking an aluminum alloy with the thickness of 20-60 mu m as a substrate, putting the aluminum alloy in an alkali liquor for pretreatment, soaking for 1-10min at the temperature of 30-60 ℃, and then washing the aluminum alloy clean by deionized water;

(2) drilling holes: placing the substrate obtained after pretreatment in the step (1) in a punching liquid for punching, soaking for 1-5min at 30-60 ℃, then washing with deionized water, and drying;

(3) passivating: coating passivation treatment liquid on one side surface of the substrate, wherein the passivation treatment liquid is triethanolamine solution, the coating temperature is 76-80 ℃, standing for 8min after coating, and then drying; according to the invention, triethanolamine is used as a passivation treatment solution of the aluminum foil, the triethanolamine has alkalescence, after the high-purity aluminum foil is immersed in the treatment solution, the surface of the aluminum foil is subjected to alkaline dissolution, a boehmite deposition film is formed on the surface of the aluminum foil, the deposition film can prevent the high-purity aluminum in the aluminum foil from further alkaline dissolution, and then the aluminum foil is subjected to high-temperature treatment, so that the content of gamma-alumina in an oxide film is increased, and the defect of environmental pollution caused by using a chromium solution as a passivating agent is avoided.

(4) Surface modification treatment: and (3) placing the substrate treated in the step (3) in a surface modification solution for modification treatment, soaking for 1-5min, washing and drying with deionized water to obtain the aluminum foil for the flexible packaging film with the compact oxide thin film layer on the surface, and after surface modification, enabling the surface of the passivation layer on the surface of the aluminum foil to be smooth and tidy, so that the aluminum foil can be conveniently connected with the heat sealing layer and the surface of the battery through the bonding layer.

as a preferable embodiment, the alkali solution in step (1) in this embodiment is a mixed solution of sodium carbonate and sodium hydroxide, wherein the concentration of sodium carbonate is 0.5-1.8 mol/l, and the concentration of sodium hydroxide in the mixed solution is 0.2-2.5 mol/l.

in a preferred embodiment, the solution for drilling in step (2) in this embodiment is a mixed solution of amino acid, sodium oxalate and sodium hydroxide, and the pH of the solution for drilling is 8.5-9.2.

As a preferable embodiment, in the mixed solution of the present example, the amount of the amino acid added is 50 parts by mass, the amount of the sodium oxalate added is 10 to 100 parts by mass, and the amount of the sodium hydroxide added is 30 to 500 parts by mass.

As a preferable embodiment, the concentration of the solution of the passivation treatment in step (3) in this example is 1.8 ml/l.

As a preferred embodiment, the drying temperature in step (3) in this embodiment is 550-580 deg.C, and the drying time is 2-3 min.

as a preferred embodiment, the amount of coating in this example is 0.02 to 0.35g/m 2.

As a preferred embodiment, in this embodiment, the surface modification solution in step (4) is a tannic acid solution, the concentration of which is 2-6mol/l, the acidity of tannic acid is weak, and the modification effect is better.

As a preferred embodiment, in the present embodiment, the soaking temperature in step (4) is 40-80 ℃, the soaking time is 30-120s, and the drying temperature is 80-120 ℃.