A composite current collector for lithium-ion batteries, its preparation method and application

Abstract

This disclosure provides a lithium-ion battery composite current collector, its preparation method, and its application, relating to the field of lithium-ion battery technology. The method includes: a serrated array base film; a polymeric composite coating layer coated on the recesses of the serrated array base film, which is a mixture of an adhesive and a high-temperature curing resin; and a metal layer electroplated on the surface of the serrated base film containing the coating layer. In the serrated array base film, the serrations are not interconnected, and each serration tip has an opposing serration tip. When the lithium-ion battery composite current collector is welded to an electrode tab, the high temperature of the welding process hardens the hardening material within the coating. Under the pressure of the welding, the high-temperature curing coating pierces the serrated array base film, allowing the metal layers on both sides to contact. This disclosure exhibits excellent welding performance, while the high-performance composite current collector high-temperature curing coating in the unwelded areas remains unmodified.

Description

Technical Field

[0001] This disclosure relates to the field of lithium-ion battery technology, specifically to a lithium-ion battery composite current collector, its preparation method, and its application. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure and do not necessarily constitute prior art.

[0003] The conventional composite current collector structure in the lithium-ion battery industry is generally a three-layer structure: a metal conductive layer, a PET / PP polymer support layer, and a metal conductive layer. PET / PP or similar polymer insulating resins serve as the intermediate layer, with aluminum or copper deposited on both the top and bottom surfaces. This novel composite current collector can improve the safety of lithium-ion batteries while also increasing their energy density.

[0004] However, conventional lithium-ion battery composite current collectors use a polymer base film in the middle layer. This makes welding difficult because the foil and tabs, being metal, are prone to poor bonding. Current solutions to the welding problem of composite current collectors mainly involve improving the welding process, such as adding roll welding or adding an external extension to the composite current collector for welding. However, these methods often increase manufacturing costs, and because the welded and unwelded parts of the composite current collector are not a complete unit, the overall performance is generally poor. Summary of the Invention

[0005] To address the aforementioned problems, this disclosure proposes a lithium-ion battery composite current collector, its preparation method, and its application. A sawtooth array composite current collector base film is prepared. The high temperature during welding with the electrode tabs causes the hardening material within the coating to harden. Under the pressure of welding, the high-temperature hardened coating pierces the polymer base film, allowing the metal plating on both sides to contact. This allows the composite current collector to possess both the excellent performance of ordinary composite current collectors and the welding effect of ordinary metal current collectors.

[0006] According to some embodiments, the present disclosure adopts the following technical solutions:

[0007] A lithium-ion battery composite current collector, comprising:

[0008] Serrated array base film;

[0009] And a polymer composite material coating layer applied to the recesses of the serrated array base film;

[0010] And a metal layer electroplated on the surface of a serrated base film containing a coating layer;

[0011] In the serrated array base film, the two serrations are not connected, and each serration tip has a corresponding serration tip.

[0012] Furthermore, the substrate thickness of the sawtooth array base film is 2–4 μm.

[0013] Furthermore, the polymer composite coating layer is a mixture of adhesive and high-temperature curing resin.

[0014] Furthermore, the adhesive is PVDF, PAA, or styrene-butadiene rubber, and the high-temperature curing resin is melamine-formaldehyde resin, phenolic resin, or epoxy resin.

[0015] Furthermore, the adhesive and the high-temperature curing resin are mixed evenly in a ratio of 1 to 3:6 to 9.

[0016] Furthermore, copper or aluminum is electroplated onto a serrated array base film containing a coating layer using magnetron sputtering, electroplating, or magnetron sputtering and evaporation.

[0017] Furthermore, the magnetron sputtering + electroplating method can be a fully wet method, a fully dry method, or a combination of wet and dry methods.

[0018] Furthermore, the thickness of the metal layer is 2–10 μm.

[0019] According to some embodiments, the present disclosure adopts the following technical solutions:

[0020] A method for preparing a lithium-ion battery composite current collector, wherein when the lithium-ion battery composite current collector is welded to the tab, the high temperature of the welding causes the hardening material in the coating to harden, and under the pressure of the welding, the high-temperature hardened coating will pierce the serrated array base film so that the metal layers on both sides can come into contact.

[0021] According to some embodiments, the present disclosure adopts the following technical solutions:

[0022] Application of a lithium-ion battery composite current collector in lithium-ion batteries.

[0023] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0024] The present invention discloses a lithium-ion battery composite current collector, wherein the base film is made into a sawtooth array, and the two sawtooths are not connected, but retain a substrate thickness of 2 to 4 μm. At the same time, the surface tips of the two sawtooths are 1 to 3 μm apart to ensure the tensile properties of the base film.

[0025] This disclosure discloses a composite current collector for lithium-ion batteries. During welding to the electrode tab, the high temperature of the welding process hardens the hardening material within the coating. Under the pressure of welding, the high-temperature hardened coating pierces the polymer base film, allowing the metal plating on both sides to contact. This enables the composite current collector to be welded like a conventional metal current collector. The welding effect of this disclosure is excellent, and the high-temperature hardened coating of the high-performance composite current collector in the unwelded areas remains unchanged. Therefore, this high-performance composite current collector possesses both the excellent performance of ordinary composite current collectors and the welding effect of ordinary metal current collectors. Furthermore, welding the electrode tab with this high-performance composite current collector does not require additional processing steps, making it convenient to use and significantly reducing operating costs. Attached Figure Description

[0026] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0027] Figure 1 The high-performance composite current collector substrate membrane described in the embodiments of this disclosure;

[0028] Figure 2 The serrated composite current collector substrate film described in the embodiments of this disclosure;

[0029] Figure 3 This is a schematic diagram of a high-temperature curing coating according to an embodiment of the present disclosure;

[0030] Figure 4 This is a schematic diagram of an embodiment of the present disclosure of an electroplated metal layer in the coating layer. Detailed Implementation

[0031] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Example

[0035] One embodiment of this disclosure provides a lithium-ion battery composite current collector, the structure of which includes a serrated array base film; a polymer hybrid material coating layer coated on the recesses of the serrated array base film; and a metal layer electroplated on the surface of the serrated base film containing the coating layer.

[0036] In the serrated array base film, the two serrations are not connected, and each serration tip has a corresponding serration tip.

[0037] As one embodiment, the method for obtaining the sawtooth array base film disclosed herein is as follows:

[0038] Step 1: Fabricate the base film 1 used for conventional high-performance composite current collectors. The base film material can be one of PP, PET, or PI, and the thickness of base film 1 is 2–10 μm. Figure 1 As shown.

[0039] Step 2: Serrated array base film 2. Using laser die-cutting or metal die-cutting, ... Figure 1 The base film shown is fabricated as follows Figure 2 The image shows a serrated pattern. The two serrations are not continuous; instead, a 2–4 ​​μm substrate thickness is maintained between them. This is because a continuous pattern would create a hole in the base film, compromising its tensile properties. Furthermore, the tips of the two serrations are 1–3 μm apart.

[0040] As one embodiment, a polymer composite material coating layer 3 is prepared. This coating layer is a mixture of an adhesive and a high-temperature curing resin. The adhesive can be PVDF, PAA, or styrene-butadiene rubber, and the high-temperature curing resin can be melamine-formaldehyde resin, phenolic resin, or epoxy resin. The preparation process involves uniformly mixing the adhesive and the high-temperature curing resin in a ratio of 1–3:6–9. Figure 3 As shown, the uniformly mixed mixture is applied to the depressions of the serrated array base film.

[0041] As one embodiment, metal layer 4 is prepared by electroplating copper or aluminum onto a serrated array base film containing a coating layer using magnetron sputtering + electroplating or vapor deposition.

[0042] Among these methods, magnetron sputtering combined with electroplating can be performed using a fully wet method, a fully dry method, or a combination of wet and dry methods. The thickness of the metal coating is 2–10 μm, resulting in... Figure 4 The high-performance composite current collector shown.

[0043] As one example, such as Figure 4The high-performance composite current collector shown can be welded to the electrode tab at high temperatures, causing the hardening material within the coating to harden. Under the pressure of welding, the high-temperature hardened coating pierces the polymer base film, allowing the metal plating on both sides to contact. This enables the composite current collector to be welded like a regular metal current collector. The welding effect is excellent, and the high-temperature hardened coating of the high-performance composite current collector in the unwelded areas remains unmodified.

[0044] Example 1

[0045] In one embodiment of this disclosure, a PET base film with a thickness of 8 μm is selected. Serrated recesses are cut into the base film using laser die-cutting, with the tips of two recesses 1.5 μm apart and the recess depth 3 μm. PVDF adhesive and melamine-formaldehyde resin (a high-temperature curing resin) are mixed uniformly at a weight ratio of 3:7. This mixture is then coated onto the serrated base film. Copper is deposited onto the surface of the composite current collector using a magnetron sputtering + electroplating wet process, resulting in a copper layer thickness of 2 μm.

[0046] Example 1 uses the high-performance composite current collector prepared as described above as the negative electrode;

[0047] Comparative Example 1-1 uses a common PET base film as the negative electrode, with a base film thickness of 8μm and a copper layer thickness of 2μm as the composite current collector.

[0048] Comparative Examples 1-2 used 12μm copper foil as the negative electrode.

[0049] Ultrasonic welding was used for the tab welding in Examples 1-1 and 1-2. In Examples 1-1 and 1-2, no auxiliary processes were used; the welding was direct spot welding. A 6Ah ternary lithium-ion cell (model 6575115) was prepared. The tab welding results are shown in Table 1 below.

[0050] Table 1. Electrode welding effect between the examples and the comparative examples.

[0051]

[0052] As can be seen from the comparison between Example 1 and Comparative Examples 1-1 and 1-2, the electrode tab welding effect of the high-performance composite current collector used in this disclosure is consistent with the performance of conventional current collectors, and its performance is far superior to that of conventional composite current collectors.

[0053] Example 2

[0054] In one embodiment of this disclosure, a PP base film with a thickness of 8 μm is selected. Serrated recesses are cut into the base film using laser die-cutting, with the tips of two recesses 1.5 μm apart and the recess depth 2.5 μm. SBR adhesive and high-temperature curing epoxy resin are mixed uniformly at a weight ratio of 4:6. This mixture is then coated onto the serrated base film. Copper is deposited onto the surface of the composite current collector using a dry method of magnetron sputtering and electroplating, resulting in a copper layer thickness of 2 μm.

[0055] Example 2 uses the high-performance composite current collector prepared above as the negative electrode;

[0056] Comparative Example 2-1 uses a common PP base film as the negative electrode, with a base film thickness of 8μm and a copper layer thickness of 2μm as the composite current collector.

[0057] Comparative Example 2-2 uses 12μm copper foil as the negative electrode.

[0058] In Example 2, Comparative Example 2-1, and Comparative Example 2-2, the tabs were welded using ultrasonic welding. In these examples, no auxiliary processes were used; the welding was direct spot welding. A 6Ah ternary lithium-ion cell (model 6575115) was prepared. The tab welding results are shown in Table 2 below.

[0059] Table 2. Electrode Welding Results

[0060]

[0061]

[0062] As can be seen from the comparison between Example 2 and Comparative Examples 2-1 and 2-2, the electrode tab welding effect of the high-performance composite current collector used in this disclosure is consistent with the performance of conventional current collectors, and its performance is far superior to that of conventional composite current collectors.

[0063] Example 3

[0064] In one embodiment of this disclosure, a PET base film with a thickness of 10 μm is selected. Serrated recesses are cut into the base film using laser die-cutting, with the tips of two recesses 1.5 μm apart and the recess depth 3.5 μm. PVDF adhesive and melamine-formaldehyde resin (a high-temperature curing resin) are mixed uniformly at a weight ratio of 3:7. This mixture is then coated onto the serrated base film. Aluminum is deposited onto the surface of the composite current collector using vapor deposition, with an aluminum layer thickness of 2 μm.

[0065] Example 3 uses the high-performance composite current collector prepared as described above as the positive electrode;

[0066] Comparative Example 3-1 uses a common PET base film with a thickness of 10 μm and an aluminum layer thickness of 2 μm as the positive electrode, forming a composite current collector.

[0067] Comparative Example 3-2 uses 14μm aluminum foil as the positive electrode.

[0068] In Example 3, Comparative Example 3-1, and Comparative Example 3-2, the tabs were welded using ultrasonic welding. In these examples, no auxiliary processes were used; the welding was direct spot welding. A 5Ah ternary lithium-ion cell (model 4075115) was prepared. The tab welding results are shown in Table 3 below.

[0069] Table 3. Electrode Welding Results

[0070]

[0071]

[0072] As can be seen from the comparison between Example 3 and Comparative Examples 3-1 and 3-2, the electrode tab welding effect of the high-performance composite current collector used in this patent is consistent with the performance of conventional current collectors, and its performance is far superior to that of conventional composite current collectors.

[0073] Example 4

[0074] One embodiment of this disclosure provides a method for preparing a lithium-ion battery composite current collector. When the lithium-ion battery composite current collector is welded to the tab, the high temperature of the welding causes the hardening material in the coating to harden. Under the pressure of the welding, the high-temperature hardened coating will pierce the serrated array base film, allowing the metal layers on both sides to come into contact.

[0075] Example 5

[0076] One embodiment of this disclosure provides a lithium-ion battery composite current collector, which is used in a lithium-ion battery.

[0077] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0078] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0079] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A composite current collector for lithium-ion batteries, characterized in that, include: Serrated array base film; And a polymer composite material coating layer applied to the recesses of the serrated array base film; The polymer composite material coating layer is a mixture of adhesive and high-temperature curing resin; And a metal layer electroplated on the surface of a serrated base film containing a coating layer; In the serrated array base film, the two serrations are not connected, and each serration tip has a corresponding serration tip.

2. The lithium-ion battery composite current collector as described in claim 1, characterized in that, The substrate thickness of the sawtooth array base film is 2~4μm.

3. The lithium-ion battery composite current collector as described in claim 1, characterized in that, The adhesive is PVDF, PAA, or styrene-butadiene rubber, and the high-temperature curing resin is melamine-formaldehyde resin, phenolic resin, or epoxy resin.

4. A lithium-ion battery composite current collector as described in claim 1, characterized in that, The adhesive and high-temperature curing resin are mixed evenly in a weight ratio of 1~3:6~9.

5. A lithium-ion battery composite current collector as described in claim 1, characterized in that, Copper or aluminum is electroplated onto a serrated array base film containing a coating layer using either magnetron sputtering + electroplating or magnetron sputtering + evaporation.

6. A lithium-ion battery composite current collector as described in claim 5, characterized in that, The magnetron sputtering + electroplating method can be a fully wet method, a fully dry method, or a combination of wet and dry methods.

7. A lithium-ion battery composite current collector as described in claim 1, characterized in that, The thickness of the metal layer is 2~10μm.

8. A method for preparing a composite current collector for lithium-ion batteries, characterized in that, When the lithium-ion battery composite current collector as described in any one of claims 1-7 is welded to the tab, the high temperature of the welding causes the hardening material in the coating to harden, and under the pressure of the welding, the high-temperature hardened coating will pierce the serrated array base film so that the metal layers on both sides can come into contact.

9. The application of a lithium-ion battery composite current collector according to any one of claims 1-7 in a lithium-ion battery.

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