Composite copper foil and preparation method thereof

Abstract

The invention discloses a composite copper foil and a preparation method thereof, and the preparation method comprises the following steps: S1, carrying out dotted line cutting treatment on a polymer substrate to obtain a plurality of dotted line cutting strips which are arranged at intervals along the width direction, and each dotted line cutting strip extends along the length direction of the polymer substrate; s2, magnetron sputtering copper plating is conducted on the first surface of the macromolecule base material, and a first copper film layer is obtained; s3, carrying out water electroplating copper on the first copper film layer to obtain a thickened first copper layer; s4, removing a plurality of dotted line cutting strips on the polymer base material; s5, magnetron sputtering copper plating is conducted on the second surface of the polymer base material, and a second copper film layer is obtained; s6, water electroplating copper is conducted on the second copper film layer, a thickened second copper layer is obtained, and meanwhile a pure copper layer is obtained at the position where the dotted line cutting strips are removed; and S7, carrying out central slitting at the position of the pure copper layer along the length direction of the polymer base material to obtain the multi-roll composite copper foil with the tab. According to the composite copper foil and the preparation method thereof, the process can be simplified, and the production efficiency can be improved.

Description

Technical Field

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

[0002] As the negative electrode current collector of lithium battery, composite copper foil has the advantages of reducing battery weight, increasing battery energy density, improving battery safety, and reducing battery cost. Compared with the composite current collector of pure copper foil, the composite current collector needs to weld the pole ear, which is used to prevent short circuit failure between metal strip and aluminum-plastic film during battery packaging. It can be sealed and bonded with aluminum-plastic film by heating (about 140℃) to prevent leakage. The pole ear is also the conductor of the positive and negative electrodes of the battery, and is used as the contact point 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 copper foil and a preparation method thereof, which can simplify the process and improve the production efficiency.

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

[0006] A method for preparing a composite copper 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, magnetron sputtering copper plating on the first surface of the polymer substrate obtained in step S1 to obtain a first copper film layer on the first surface of the polymer substrate;

[0009] S3, electroplating copper on the first copper film layer on the first surface of the polymer substrate obtained in step S2 to obtain a thickened first copper layer

[0010] S4, removing a plurality of dotted cutting strips on the polymer substrate obtained in step S3;

[0011] S5, copper-plating the second surface of the polymer substrate obtained in step S4 by magnetron sputtering to obtain a second copper film layer on the second surface of the polymer substrate;

[0012] S6, electroplating copper on the second copper film layer on the second surface of the polymer substrate obtained in step S5 to obtain a thickened second copper layer, and at the same time obtaining a pure copper layer at the position where the dotted line cutting strip is removed;

[0013] S7, cutting the polymer substrate obtained in step S6, and cutting the polymer substrate in the middle along the length direction at the position of the pure copper layer to obtain multiple rolls of composite copper foil with tabs.

[0014] 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.

[0015] In some embodiments, the thickness of the polymer substrate in step S1 is 4.35-4.65 μm.

[0016] 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.

[0017] In some embodiments, the width of the dashed line cutting strip in step S1 is 20-30 mm.

[0018] In some embodiments, the thickness of the first copper film layer in step S2 is 70-90 nm, and the thickness of the second copper film layer in step S5 is 70-90 nm.

[0019] In some embodiments, the thickness of the first copper layer in step S3 is 900-1100 nm, and the thickness of the second copper layer in step S6 is 900-1100 nm.

[0020] In some of the embodiments, in step S4, the polymer substrate after the first surface copper plating is rewound, and a plurality of dotted line cutting strips are torn off during the rewinding process.

[0021] In some embodiments, in step S7, a slitting machine is used to slit the polymer substrate.

[0022] Based on the above problems, the present invention also provides another technical solution:

[0023] A composite copper foil is prepared according to any one of the above-mentioned methods for preparing the composite copper foil.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] A dotted line cutting strip is cut on a polymer substrate, copper is first plated on the first surface of the polymer substrate, copper is plated on the second surface of the polymer substrate after removing the dotted line cutting strip, and finally a center cut is performed at the position of the pure copper layer to obtain a multi-roll composite copper foil with a built-in tab. This method omits the tab welding process, simplifies the process, improves production efficiency, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figures 1 to 6 A schematic diagram of a process for preparing a composite copper foil of the present invention;

[0028] Figure 7 This is a schematic diagram of the cutting step in Example 1 of the present invention;

[0029] in:

[0030] 1. Polymer substrate; 1-1. Dotted line cutting strip;

[0031] 2. The first copper film layer;

[0032] 3. The first copper layer;

[0033] 4. The second copper film layer;

[0034] 5. Second copper layer;

[0035] 6. Pure copper layer;

[0036] 7. Centered cutting line;

[0037] 100. Copper foil;

[0038] 200, ear;

[0039] 300, invalid area;

[0040] 400. Cutting line. DETAILED DESCRIPTION

[0041] 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.

[0042] A method for preparing a composite copper foil, characterized in that it comprises the following steps:

[0043] S1, perform dotted line cutting on the polymer substrate 1, such as Figure 1 The figure shows a longitudinal cross section of a polymer substrate 1, on which a plurality of dotted line cutting strips 1-1 are arranged at intervals along the width direction, and each dotted line cutting strip 1-1 extends along the length direction of the polymer substrate 1;

[0044] S2, magnetron sputtering copper plating on the first surface of the polymer substrate 1 obtained in step S1, such as Figure 2 As shown, a first copper film layer 2 is obtained on the first surface of the polymer substrate 1;

[0045] S3, electroplating copper on the first copper film layer 2 on the first surface of the polymer substrate 1 obtained in step S2 to obtain a thickened first copper layer 3 (such as Figure 3 shown);

[0046] S4, removing several dotted cutting strips on the polymer substrate 1 obtained in step S3; S5, magnetron sputtering copper-plating the second surface of the polymer substrate 1 obtained in step S4, and obtaining a second copper film layer 4 (such as Figure 4 shown);

[0047] S6, electroplating copper on the second copper film layer on the second surface of the polymer substrate 1 obtained in step S5 to obtain a thickened second copper layer 5, and at the same time obtaining a pure copper layer 6 (such as Figure 5 shown);

[0048] S7, the polymer substrate obtained in step S6 is cut in the middle along the length direction of the polymer substrate 1 at the position of the pure copper layer 6 to obtain a plurality of rolls of composite copper foil with self-attached tabs (such as Figure 1 shown).

[0049] 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 4.35-4.65 μm.

[0050] In step S1, a slitting machine is used to cut the dotted lines. The number of dotted line cuts is set as needed. 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 1-1 need to be cut, four passive circular knives need to be installed, and the polymer substrate is rolled 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.

[0051] 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.

[0052] In step S2, the polymer substrate 1 cut by the dotted line is loaded onto a winding magnetron coating machine for magnetron sputtering copper plating at a speed of 15 m / min, the total power of six copper targets on a single side is controlled at 100±5 kW, the ion source cleaning voltage is 700 V, and a first copper film layer 2 with a thickness of 70 to 90 nm is obtained on the first surface of the polymer substrate 1.

[0053] In step S3, the polymer substrate 1 that has been subjected to magnetron sputtering copper plating is fed to a water plating line for copper thickening on the first surface at a speed of 10 m / min and a total rectifier current of 5000±500 A, so that the thickness of the thickened first copper layer 3 is 900-1100 nm.

[0054] In step S4, the polymer substrate 1 that has completed the first surface copper 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.

[0055] In step S5, the polymer substrate 1 with the dotted line cut strip torn off is loaded onto a winding magnetron coating machine for magnetron sputtering copper coating at a speed of 15 m / min, the total power of six copper targets on a single side is controlled at 100±5 kW, the ion source cleaning voltage is 700 V, and a second copper film layer 4 with a thickness of 70 to 90 nm is obtained on the second surface of the polymer substrate.

[0056] In step S6, the polymer substrate 1 that has been subjected to magnetron copper plating is fed to a water plating line for copper thickening on the second surface at a speed of 10 m / min and a total rectifier current of 5000±500 A, so that the thickness of the thickened second copper layer 5 is 900-1100 nm.

[0057] In step S7, 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 copper layer 6, such as Figure 6 As shown, the cutter cuts along the center slitting line 7, the cutter slitting speed is 50m / min, the equipment running speed is 80m / min, the unwinding tension is 100N±20N, and the winding tension equipment is adaptively adjusted to obtain multiple rolls of composite copper foil with built-in tabs.

[0058] 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 copper 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:

[0059] S 1. Place a PET substrate roll with a width of 1350mm on the 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;

[0060] S2. Load the polymer substrate cut by the dotted line onto a winding magnetron coating machine for magnetron sputtering copper plating at a speed of 15 m / min. The total power of six copper targets on a single side is controlled at 100±5 kW. The ion source cleaning voltage is 700 V. A first copper film layer with a thickness of 80 nm is obtained on the first surface of the polymer substrate.

[0061] S3. Load the polymer substrate that has completed magnetron sputtering copper plating to the water plating line for thickening copper plating on the first surface at a speed of 10m / min and a total rectifier current of 5000±500A, so that the thickness of the thickened first copper layer is 1000nm.

[0062] S4. The polymer substrate that has been copper plated on the first surface is rewound. The polymer substrate can be loaded onto a rewinder. During the rewinding process, a number of dotted line cutting strips 1-1 are torn off, and the torn off dotted line cutting strips are wound onto a waste discharge roller. The equipment runs at a speed of 40 m / min, the unwinding tension is 100 N ± 20 N, and the winding tension device can be adjusted adaptively.

[0063] S5. Load the polymer substrate with the dotted line cut strip removed onto a winding magnetron coating machine for magnetron sputtering copper coating at a speed of 15 m / min. The total power of six copper targets on a single side is controlled at 100±5 kW. The ion source cleaning voltage is 700 V. A second copper film layer with a thickness of 80 nm is obtained on the second surface of the polymer substrate.

[0064] S6. Load the polymer substrate that has completed the magnetron copper plating to the water plating line for thickening the copper plating on the second surface at a speed of 10 m / min and a total rectifier current of 5000±500 A, so that the thickness of the thickened second copper layer is 1000 nm.

[0065] S7. Use a slitting machine to slit the polymer substrate, and perform centered slitting along the length direction of the polymer substrate at the position of the pure copper layer, such as Figure 7As shown, the cutter cuts along the slitting line 400, there are five slitting circular blades, each of which is 285 mm apart, the slitting speed is 50 m / min, the equipment running speed is 80 m / min, the unwinding tension is 100 N ± 20 N, and the winding tension equipment is adaptively adjusted to obtain four rolls of composite copper foil with built-in tabs, each roll of composite copper foil includes a copper foil 100 and a tab 200 located on one side of the copper foil 100.

[0066] In summary, the preparation method omits the tab welding process, simplifies the process steps, improves production efficiency, and reduces production costs.

[0067] 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 copper 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, magnetron sputtering copper-plating the first surface of the polymer substrate obtained in step S1 to obtain a first copper film layer on the first surface of the polymer substrate; S3, electroplating copper on the first copper film layer on the first surface of the polymer substrate obtained in step S2 to obtain a thickened first copper layer; S4, removing a plurality of dotted cutting strips on the polymer substrate obtained in step S3; S5, copper-plating the second surface of the polymer substrate obtained in step S4 by magnetron sputtering to obtain a second copper film layer on the second surface of the polymer substrate; S6, electroplating copper on the second copper film layer on the second surface of the polymer substrate obtained in step S5 to obtain a thickened second copper layer, and at the same time obtaining a pure copper layer at the position where the dotted line cutting strip is removed; S7, cutting the polymer substrate obtained in step S6, and cutting the polymer substrate in the middle along the length direction at the position of the pure copper layer to obtain multiple rolls of composite copper foil with tabs.

2. The method for preparing the composite copper 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 copper foil according to claim 2, characterized in that: In step S1, the thickness of the polymer substrate is 4.35-4.65 μm.

4. The method for preparing the composite copper 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 the composite copper 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 the composite copper foil according to claim 1, characterized in that: The thickness of the first copper film layer in step S2 is 70-90 nm, and the thickness of the second copper film layer in step S5 is 70-90 nm.

7. The method for preparing the composite copper foil according to claim 1, characterized in that: The thickness of the first copper layer in step S3 is 900-1100 nm, and the thickness of the second copper layer in step S6 is 900-1100 nm.

8. The method for preparing the composite copper foil according to claim 1, characterized in that: In step S4, the polymer substrate with the first surface copper-plated is rewound, and a plurality of dotted line cutting strips are torn off during the rewinding process.

9. The method for preparing the composite copper foil according to claim 1, characterized in that: In step S7, a slitting machine is used to slit the polymer substrate.

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

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