Composite aluminum foil and preparation method thereof

Abstract

The invention discloses a composite aluminum foil and a preparation method thereof.The method comprises the following steps that S1, dotted line cutting treatment is conducted on a macromolecule base material, a plurality of dotted line cutting strips arranged at intervals in the width direction are obtained on the macromolecule base material, and each dotted line cutting strip extends in the length direction of the macromolecule base material; s2, aluminum plating treatment is conducted on the first surface of the polymer base material, and a first aluminum plating layer is obtained on the first surface of the polymer base material; s3, removing a plurality of dotted line cutting strips on the polymer base material; s4, aluminum plating treatment is conducted on the second surface of the polymer base material, a second aluminum plating layer is obtained on the second surface of the polymer base material, and meanwhile a pure aluminum layer is formed at the position where the dotted line cutting strips are removed; and S5, the polymer base material is subjected to slitting treatment, center slitting is carried out at the position of the pure aluminum layer in the length direction of the polymer base material, and the multi-roll composite aluminum foil with the tabs is obtained. According to the composite aluminum foil and the preparation method thereof, the process can be simplified, and the production efficiency can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of current collectors, and in particular to a composite aluminum foil and a preparation method thereof. Background Art

[0002] As the positive electrode current collector of lithium batteries, composite aluminum foil has the advantages of reducing battery weight, increasing battery energy density, improving battery safety, and reducing battery costs. Compared with pure aluminum foil composite current collectors, composite current collectors require welding pole ears, which are used to prevent short circuit failures between metal strips and aluminum-plastic films during battery packaging. They can be hot-melt sealed and bonded to the aluminum-plastic film by heating (about 140°C) to prevent leakage. The pole ears are also the conductors of the positive and negative electrodes of the battery, and are used as contact points during charging and discharging. Lithium-ion batteries use a multi-pole ear structure stacking form, which has good conductivity, rate performance and safety.

[0003] Since a welding process is required to prepare the tabs, the process time and process cost will increase accordingly. Summary of the invention

[0004] The present invention aims to provide a composite aluminum foil and a preparation method thereof, which can simplify the process and improve production efficiency.

[0005] Based on the above problems, the technical solution provided by the present invention is:

[0006] A method for preparing a composite aluminum foil comprises the following steps:

[0007] S1, performing a dotted line cutting process on the polymer substrate to obtain a plurality of dotted line cutting strips arranged at intervals along the width direction on the polymer substrate, each dotted line cutting strip extending along the length direction of the polymer substrate;

[0008] S2, performing aluminum plating on the first surface of the polymer substrate obtained in step S1 to obtain a first aluminum plating layer on the first surface of the polymer substrate;

[0009] S3, removing a plurality of dotted cutting strips on the polymer substrate obtained in step S2;

[0010] S4, performing aluminum plating on the second surface of the polymer substrate obtained in step S3, obtaining a second aluminum plating layer on the second surface of the polymer substrate, and forming a pure aluminum layer at the position where the dotted line cutting strip is removed;

[0011] S5, cutting the polymer substrate obtained in step S4, and cutting the polymer substrate in the middle along the length direction at the position of the pure aluminum layer to obtain multiple rolls of composite aluminum foil with tabs.

[0012] In some embodiments, the polymer substrate in step S1 is one of a PET substrate, a PP substrate, a PI substrate, and a PPS substrate.

[0013] In some embodiments, the thickness of the polymer substrate in step S1 is 5.85-6.15 μm.

[0014] In some embodiments, a slitting machine is used to perform dotted line cutting in step S1, and the specifications of the passive circular knife used are: dotted line length is 2.5 mm, dotted line spacing is 1.3 mm, and cutting depth is 0.5 mm.

[0015] In some embodiments, the width of the dashed line cutting strip in step S1 is 20-30 mm.

[0016] In some embodiments, in step S2, aluminum is plated using an evaporation aluminum plating process, and the thickness of the first aluminum plating layer is 900-1100 nm.

[0017] In some of the embodiments, in step S3, the polymer substrate with the aluminum-plated first surface is rewound, and a plurality of dotted line cutting strips are torn off during the rewinding process.

[0018] In some embodiments, in step S4, aluminum is plated using an evaporation aluminum plating process, and the thickness of the second aluminum plating layer is 900-1100 nm.

[0019] In some embodiments, in step S5, a slitting machine is used to slit the polymer substrate.

[0020] Based on the above problems, the present invention also provides another technical solution:

[0021] A composite aluminum foil is prepared according to any one of the above-mentioned methods for preparing the composite aluminum foil.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] A dotted line cutting strip is cut on the polymer substrate, aluminum is first plated on the first surface of the polymer substrate, and aluminum is plated on the second surface of the polymer substrate after removing the dotted line cutting strip. Finally, a center cut is performed at the position of the pure aluminum layer to obtain multiple rolls of composite aluminum foil with built-in tabs. This method omits the tab welding process, simplifies the process, improves production efficiency, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. The accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0025] Figures 1 to 4A schematic diagram of a process for preparing a composite aluminum foil of the present invention;

[0026] Figure 5 This is a schematic diagram of the cutting step in Example 1 of the present invention;

[0027] in:

[0028] 1. Polymer substrate; 1-1. Dotted line cutting strip;

[0029] 2. The first aluminum coating;

[0030] 3. Second aluminum coating;

[0031] 4. Pure aluminum layer;

[0032] 5. Centered cutting line;

[0033] 100. Aluminum foil;

[0034] 200, ear;

[0035] 300, invalid area;

[0036] 400. Cutting line. DETAILED DESCRIPTION

[0037] The above scheme is further described below in conjunction with specific examples. It should be understood that these examples are used to illustrate the present invention and are not limited to the scope of the present invention. The implementation conditions adopted in the examples can be further adjusted according to the conditions of the specific manufacturer, and the unspecified implementation conditions are usually the conditions in conventional experiments.

[0038] The present invention provides a method for preparing a composite aluminum foil, comprising the following steps:

[0039] S1, perform dotted line cutting on the polymer substrate 1, such as Figure 1 It is a longitudinal cross-sectional view of a polymer substrate 1, on which a plurality of dotted line cutting strips 1-1 arranged at intervals along the width direction are obtained, and each dotted line cutting strip 1-1 extends along the length direction of the polymer substrate 1;

[0040] S2, performing aluminum plating on the first surface of the polymer substrate 1 obtained in step S1, and obtaining a first aluminum plating layer 2 (such as Figure 2 shown);

[0041] S3, removing a plurality of dotted cutting strips 1-1 on the polymer substrate 1 obtained in step S2;

[0042] S4, the second surface of the polymer substrate 1 obtained in step S3 is subjected to aluminum plating treatment to obtain a second aluminum plating layer 3 on the second surface of the polymer substrate 1, and a pure aluminum layer 4 (such as Figure 3 shown);

[0043] S5, cutting the polymer substrate 1 obtained in step S4, and cutting the polymer substrate 1 in the middle along the length direction at the position of the pure aluminum layer 4 to obtain multiple rolls of composite aluminum foil with tabs.

[0044] In step S1, the polymer substrate 1 is one of a PET substrate, a PP substrate, a PI substrate, and a PPS substrate, and the thickness of the polymer substrate 1 is 5.85 to 6.15 μm. In step S1, a slitting machine is used for dotted line cutting, and the number of dotted line cutting strips is set according to needs. The specifications of the passive circular knife used are: the dotted line length is 2.5 mm, the dotted line spacing is 1.3 mm, and the cutting depth is 0.5 mm. For example, if two dotted line cutting strips need to be cut, four passive circular knives need to be installed, and the polymer substrate roll is placed on the slitting machine, and the dotted line cutting is performed under the conditions of 80 m / min and unwinding tension of 100 N ± 20 N.

[0045] The width of the dotted line cutting strip 1-1 is 20-30 mm, and the width of the dotted line cutting strip 1-1 can be set according to the width of the tab. For example, if the width of the tab is X mm, the width of the dotted line cutting strip 1-1 is 2X mm.

[0046] In step S2, an evaporation aluminum plating process is used for aluminum plating. The polymer substrate 1 cut by the dotted line is loaded and wound onto an evaporation coating machine. Aluminum is evaporated and plated under the conditions of a speed of 20 m / min, a wire feeding speed of 300 mm / min, and a unwinding tension of 300 N. A first aluminum plating layer 2 having a thickness of 900 to 1100 nm is obtained on the first surface of the polymer substrate 1.

[0047] In step S3, the polymer substrate 1 that has completed the first surface aluminum plating is rewound. The polymer substrate 1 can be loaded onto a rewinder or a slitting machine. During the rewinding process, several dotted line cutting strips 1-1 are torn off, and the torn dotted line cutting strips 1-1 are wound onto a waste discharge roller. The equipment runs at a speed of 40m / min, the unwinding tension is 100N±20N, and the winding tension device can be adaptively adjusted.

[0048] In step S4, aluminum is plated by evaporation aluminum plating process. The polymer substrate 1 with the dotted line cut strip removed is loaded onto a winding evaporation coating machine. The evaporation aluminum plating is performed under the conditions of a speed of 20 m / min, a wire feeding speed of 300 mm / min, and an unwinding tension of 300 N. The thickness of the second aluminum plating layer 3 obtained on the second surface of the polymer substrate 1 is 900 to 1100 nm.

[0049] In step S5, a slitting machine is used to slit the polymer substrate 1, and a slitting is performed in the middle along the length direction of the polymer substrate 1 at the position of the pure aluminum layer 4. Figure 4As shown, the cutter cuts along the center slitting line 5, the cutter slitting speed is 100m / min, the equipment running speed is 100m / min, the unwinding tension is 120N±20N, and the winding tension device is adaptively adjusted to obtain multiple rolls of composite aluminum foil with built-in tabs.

[0050] The following is a specific embodiment 1 for actual production needs, with specific requirements: the width of the tab 200 is 15 mm, the width of the aluminum foil 100 is 270 mm, and the polymer substrate is a PET substrate with a width of 1350 mm. The specific implementation steps are as follows:

[0051] S1. Place a PET substrate roll with a width of 1350mm on a slitting machine. According to the production requirements, the number of dotted line cutting strips is two, the dotted line cutting interval is 540mm in the middle, and the invalid area of ​​300 with a width of 105mm on both sides of the width direction of the PET substrate is 105mm. The specifications of the passive circular knife used for dotted line cutting are: dotted line length is 2.5mm, dotted line spacing is 1.3mm, and cutting depth is 0.5mm. Install four passive blades on the slitting machine, adjust the position of the circular knife, and perform dotted line cutting under the conditions of 80m / min and unwinding tension of 100N±20N;

[0052] S2. Load the polymer substrate cut by the dotted line into a roll-to-roll evaporation coating machine, evaporate aluminum at a speed of 20 m / min, a wire feeding speed of 300 mm / min, and an unwinding tension of 300 N, and obtain a first aluminum coating with a thickness of 1000 nm on the first surface of the polymer substrate.

[0053] S3. Load the polymer substrate with the first surface aluminum plating to the rewinding machine. During the rewinding process, tear off the dotted line cutting strip and wind it onto the waste discharge roller. The equipment runs at a speed of 40m / min, the unwinding tension is 100N±20N, and the rewinding tension device can be adjusted adaptively.

[0054] S4. Load the polymer substrate with the two dotted line cut strips to a roll-to-roll evaporation coating machine, and perform aluminum evaporation coating under the conditions of a speed of 20 m / min, a wire feeding speed of 300 mm / min, and an unwinding tension of 300 N, to obtain a second aluminum coating with a thickness of 1000 nm on the second surface of the polymer substrate.

[0055] S5. Use a slitting machine to slit the polymer substrate, such as Figure 5 As shown, slitting is performed along the slitting line 400, and slitting is performed in the center along the length direction of the polymer substrate at the position of the pure aluminum layer. There are five slitting circular blades, each of which is 285 mm apart. The slitting speed of the slitting blade is 100 m / min, the equipment running speed is 100 m / min, the unwinding tension is 120 N ± 20 N, and the winding tension equipment is adaptively adjusted to obtain four rolls of composite aluminum foil with built-in tabs. Each roll of composite aluminum foil includes an aluminum foil 100 and a tab 200 located on one side of the aluminum foil 100.

[0056] In summary, the preparation method omits the tab welding process, simplifies the process steps, improves production efficiency, and reduces production costs.

[0057] The above examples are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite aluminum foil, characterized in that: The following steps are involved: S1, performing a dotted line cutting process on the polymer substrate to obtain a plurality of dotted line cutting strips arranged at intervals along the width direction on the polymer substrate, each dotted line cutting strip extending along the length direction of the polymer substrate; S2, performing aluminum plating on the first surface of the polymer substrate obtained in step S1 to obtain a first aluminum plating layer on the first surface of the polymer substrate; S3, removing a plurality of dotted cutting strips on the polymer substrate obtained in step S2; S4, performing aluminum plating on the second surface of the polymer substrate obtained in step S3, obtaining a second aluminum plating layer on the second surface of the polymer substrate, and forming a pure aluminum layer at the position where the dotted line cutting strip is removed; S5, cutting the polymer substrate obtained in step S4, and cutting the polymer substrate in the middle along the length direction at the position of the pure aluminum layer to obtain multiple rolls of composite aluminum foil with tabs.

2. The method for preparing a composite aluminum foil according to claim 1, characterized in that: In step S1, the polymer substrate is one of a PET substrate, a PP substrate, a PI substrate, and a PPS substrate.

3. The method for preparing the composite aluminum foil according to claim 2, characterized in that: In step S1, the thickness of the polymer substrate is 5.85-6.15 μm.

4. The method for preparing a composite aluminum foil according to claim 1, characterized in that: In step S1, a slitting machine is used to perform dotted line cutting, and the specifications of the passive circular knife used are: dotted line length is 2.5 mm, dotted line spacing is 1.3 mm, and cutting depth is 0.5 mm.

5. The method for preparing a composite aluminum foil according to claim 1, characterized in that: The width of the dotted line cutting strip in step S1 is 20 to 30 mm.

6. The method for preparing a composite aluminum foil according to claim 1, characterized in that: In step S2, aluminum is plated by evaporation aluminum plating process, and the thickness of the first aluminum plating layer is 900-1100 nm.

7. The method for preparing a composite aluminum foil according to claim 1, characterized in that: In step S3, the polymer substrate with the aluminum-plated first surface is rewound, and a plurality of dotted line cutting strips are torn off during the rewinding process.

8. The method for preparing a composite aluminum foil according to claim 1, characterized in that: In step S4, aluminum is plated by evaporation aluminum plating process, and the thickness of the second aluminum plating layer is 900-1100 nm.

9. The method for preparing a composite aluminum foil according to claim 1, characterized in that: In step S5, a slitting machine is used to slit the polymer substrate.

10. A composite aluminum foil, characterized in that: The composite aluminum foil is prepared according to the preparation method of any one of claims 1 to 9.

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