Composite current collector, electrode plate and lithium battery

Abstract

The utility model provides a composite current collector, an electrode plate and a lithium battery. The composite current collector comprises a middle layer and a metal layer, the middle layer is configured to be an insulating film body, and an upper surface and a lower surface for the metal layer are formed on the insulating film body; the metal layer comprises a first metal layer and a second metal layer, the first metal layer is formed on the upper surface and the lower surface through sputtering, and the second metal layer is formed on the first metal layer through electroplating; the composite current collector further comprises a through hole penetrating through the metal layer and the middle layer; a plurality of through holes are regularly arranged on the surface of the composite current collector, and the through holes are filled with conductors formed by slurry formed by mixing a binder and a conductive agent; the conductor is filled in the through hole to enable the metal layers on the two sides of the insulating film body to form a conductive path, and the conductor is composed of the slurry formed by mixing the binder and the conductive agent, so that the overall conductivity can be improved, the functional diversity can be improved, and the energy density and the safety performance of the battery can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage, and in particular to a composite current collector, an electrode sheet and a lithium battery. Background Art

[0002] When it comes to current collectors in lithium-ion batteries, a novel technology is available: composite current collectors, which bring higher safety and energy density to the battery. This technology utilizes a sandwich structure, combining a middle insulating layer and metal layers on both sides, thereby improving performance while reducing the weight of the battery.

[0003] However, one challenge in the manufacture of the composite current collector is that an additional welding process is required during the packaging process to connect the metal layers on both sides, which greatly increases the production cost. However, the latest research and technological innovations are looking for solutions to simplify the manufacturing process and reduce costs. Existing methods involve joining technology or material selection, such as special pressing, bonding or conductive adhesives to replace traditional welding methods. Continuous engineering research will also introduce new design schemes to improve the structural design and material selection of the composite current collector to reduce or eliminate the parts that require additional welding, thereby improving production efficiency and reducing costs.

[0004] Therefore, although composite current collector technology provides significant battery performance improvements, technological innovation and improvement efforts targeting production costs are expected to solve the challenges in its manufacturing and bring better cost-effectiveness and sustainable development to the battery industry. Utility Model Content

[0005] In view of this, the purpose of the present invention is to provide a composite current collector, an electrode sheet and a lithium battery to solve the above problems.

[0006] The utility model adopts the following scheme:

[0007] The present application provides a composite current collector, comprising an intermediate layer and a metal layer; the intermediate layer is configured as an insulating film body, and the insulating film body is formed with an upper surface and a lower surface for the metal layer; the metal layer comprises a first metal layer and a second metal layer, the first metal layer is sputtered on the upper surface and the lower surface, and the second metal layer is electroplated on the first metal layer; the composite current collector also includes through holes penetrating the metal layer and the intermediate layer; a plurality of the through holes are regularly arranged on the surface of the composite current collector, and the through holes are filled with a conductor composed of a slurry mixed with a binder and a conductive agent.

[0008] As a further improvement, the insulating film body is one of PET, PP, and PI, and its thickness ranges from 2 μm to 12 μm.

[0009] As a further improvement, the first metal layer is at least one of copper, aluminum, nickel, iron, chromium, titanium, molybdenum and cobalt, and its thickness ranges from 10 nm to 1000 nm.

[0010] As a further improvement, the second metal layer is at least one of copper, aluminum, nickel, iron, chromium, titanium, molybdenum and cobalt, and its thickness ranges from 500nm to 5000nm.

[0011] As a further improvement, the material of the second metal layer is different from the material of the first metal layer.

[0012] As a further improvement, the diameter of the through holes ranges from 1 μm to 100 μm, and the distribution density ranges from 1 to 10,000 per m 2 .

[0013] As a further improvement, the binder is CMC-Li, which is used to supplement lithium into the conductor.

[0014] As a further improvement, the conductive agent material is a carbon material and a metal powder material, the carbon material includes carbon nanotubes, graphene, conductive carbon black, or graphite material, and the metal powder includes gold, silver, platinum, copper, iron, nickel, or cobalt powdered metal material.

[0015] The present application further provides an electrode sheet, comprising the above-mentioned composite current collector.

[0016] The present application also provides a lithium battery, comprising the above-mentioned electrode sheet.

[0017] The present application also provides a preparation method for producing the above-mentioned composite current collector, comprising the following steps:

[0018] S1: providing an insulating film body with a preset thickness, and forming a first metal layer with a first thickness on the upper surface and the lower surface of the film body respectively by magnetron sputtering;

[0019] S2: forming a second metal layer having a second thickness on the first metal layer by an electroplating process;

[0020] S3: drilling holes along the upper and lower surfaces by laser technology, and forming multiple through holes evenly distributed at equal intervals;

[0021] S4: mixing lithium carboxymethyl cellulose and carbon nanotubes with water according to a preset ratio to form a slurry, and mixing the slurry evenly by ball milling;

[0022] S5: Spreading the evenly mixed slurry on the surface of the second metal layer by a scraper, so that the slurry penetrates into the through hole and fills the hole, so as to form a composite current collector with a conductor provided in the through hole.

[0023] By adopting the above technical solution, the utility model can achieve the following technical effects:

[0024] The composite current collector of the present application isolates a metal layer relatively arranged on the upper surface and a metal layer on the lower surface in the middle layer of the insulating film body, and the metal layer has an inner first metal layer and an outer second metal layer. The first metal layer is sputtered on the surface of the insulating film body, and the second metal layer is electroplated on the surface of the first metal layer. Through holes penetrating the metal layer and the middle layer, conductors are filled in the through holes to form conductive paths between the metal layers on both sides of the insulating film body, and the conductors are composed of a slurry mixed with a binder and a conductive agent. It can not only improve the overall conductivity and improve functional diversity, but also greatly improve the energy density and safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the composite current collector of an embodiment of the utility model;

[0026] Figure 2 It is a partially enlarged schematic diagram of a composite current collector according to an embodiment of the utility model;

[0027] Figure 3 It is a flowchart of the method for preparing the composite current collector according to an embodiment of the utility model.

[0028] Icon: 1-insulating film body; 2-first metal layer; 3-second metal layer; 4-conductor. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is sought, but merely represents the selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0030] Example

[0031] Combination Figure 1As shown in the figure, the present embodiment provides a composite current collector, including an intermediate layer and a metal layer; the intermediate layer is configured as an insulating film body 1, and the insulating film body 1 is formed with an upper surface and a lower surface for the metal layer. The metal layer includes a first metal layer 2 and a second metal layer 3, the first metal layer 2 is sputtered on the upper surface and the lower surface, and the second metal layer 3 is electroplated on the first metal layer 2.

[0032] The composite current collector further comprises through holes penetrating the metal layer and the intermediate layer. A plurality of the through holes are regularly arranged on the surface of the composite current collector, and the through holes are filled with a conductor 4 composed of a slurry mixed with a binder and a conductive agent.

[0033] The composite current collector mentioned above isolates the metal layer relatively arranged on the upper surface and the metal layer on the lower surface in the middle layer of the insulating film body 1, and the metal layer has an inner first metal layer 2 and an outer second metal layer 3. The first metal layer 2 is sputtered on the surface of the insulating film body 1, and the second metal layer 3 is electroplated on the surface of the first metal layer 2. Through the through holes penetrating the metal layer and the middle layer, the conductor 4 is filled in the through holes to form a conductive path for the metal layers on both sides of the insulating film body 1, and the conductor 4 is composed of a slurry mixed with a binder and a conductive agent, which can not only improve the overall conductivity and improve the functional diversity, but also greatly improve the energy density and safety performance of the battery.

[0034] In this embodiment, the insulating film body 1 is one of PET, PP, and PI, and its thickness ranges from 2μm to 12μm. Preferably, the preset thickness of the middle layer formed by the insulating film body 1 is 7μm, which is moderate and conducive to the stable formation of the sandwich structure. The selected insulating film body 1 can be one of PET (polyester film), PP (polypropylene film), or PI (polyimide film), all of which have good insulation properties, and the thickness ranges from 2 microns to 12 microns. This range can provide sufficient insulation protection while maintaining the flexibility and stability of the film. Moreover, the preset thickness of the insulating film body 1 is 7 microns, which can ensure sufficient insulation performance without making the overall structure too thick, which is conducive to maintaining the stability of the sandwich structure, and the moderate thickness helps to ensure the stability and durability of the battery assembly, and is also conducive to operability and control during the manufacturing process.

[0035] In this embodiment, the first metal layer 2 is at least one of copper, aluminum, nickel, iron, chromium, titanium, molybdenum, and cobalt, and its thickness ranges from 10nm to 1000nm. Preferably, the first metal layer 2 is a 100nm copper metal layer. Thus, the selection of a suitable thickness can be adjusted according to the conductivity and application requirements of different metals to balance performance and cost. A further selection is a 100 nanometer thick copper metal layer, which has good conductivity and mechanical properties and provides good support for the conductivity of the battery. At the same time, a moderate thickness helps to avoid adding too much weight or cost while maintaining high conductivity. Therefore, the design of selecting copper as the first metal layer 2 is intended to provide good conductivity and maintain good performance and stability under conditions of moderate thickness, which helps to improve the overall performance of the battery and find a balance between cost and performance.

[0036] In this embodiment, the second metal layer 3 is at least one of copper, aluminum, nickel, iron, chromium, titanium, molybdenum, and cobalt, and its thickness ranges from 500nm to 5000nm. Preferably, the second metal layer 3 is an aluminum metal layer of 1μm. The selection of its thickness range depends on the characteristics of the selected metal, and it is necessary to balance the electrical conductivity, mechanical strength and other functions. A metal layer of moderate thickness can provide sufficient electrical conductivity and ensure the stability of the structure while keeping the battery lightweight. Therefore, the selection of the aluminum metal layer of the second metal layer 3 provides a certain flexibility to meet the needs of specific battery designs.

[0037] The material of the second metal layer 3 is different from that of the first metal layer 2. The second metal layer 3 is an aluminum metal layer, which can be oxidized to form a surface protective film, thereby reducing unnecessary process flows.

[0038] In this embodiment, the diameter of the through holes ranges from 1 μm to 100 μm, and the distribution density ranges from 1 to 10,000 per m. 2 The via diameter within this range can provide enough space to allow the conductive agent and adhesive paste to fill and connect the two opposite metal layers. In addition, the distribution density of the vias is between 1 and 10,000 per square meter. A lower density may make the vias more sparse, while a higher density may make the vias more dense.

[0039] Preferably, the diameter of the through holes is 30 μm and the density is 5 holes / cm 2 The through-holes are designed to form an effective conductive network, which helps to connect the metal layers on the upper and lower surfaces through the conductor 4 and improve the charge transfer efficiency inside the battery. Therefore, the selection of the through-hole diameter and distribution density will directly affect the conductivity and overall performance of the battery.

[0040] In this embodiment, the binder is CMC-Li, which is used to replenish lithium into the conductor 4. Therefore, the lithium replenishing binder added in the through hole can provide lithium replenishing function for the lithium ion battery and improve the cycle performance of the lithium ion battery.

[0041] In this embodiment, the conductive agent material is a carbon material and a metal powder material, wherein the carbon material includes carbon nanotubes, graphene, conductive carbon black, or graphite material, and the metal powder includes gold, silver, platinum, copper, iron, nickel, or cobalt powdered metal material. Thus, the selection of carbon material and metal powder as conductive agents provides a wide range of choices to meet different battery designs and performance requirements.

[0042] The present embodiment further provides an electrode sheet, including the composite current collector. And the present embodiment further provides a lithium battery, including the electrode sheet.

[0043] In conjunction with the figure, this embodiment also provides a preparation method for manufacturing the above-mentioned composite current collector, comprising the following steps:

[0044] S1: providing an insulating film body 1 with a preset thickness, and forming a first metal layer 2 with a first thickness on the upper surface and the lower surface of the film body respectively by magnetron sputtering;

[0045] S2: forming a second metal layer 3 having a second thickness on the first metal layer 2 by an electroplating process;

[0046] S3: drilling holes along the upper and lower surfaces by laser technology, and forming multiple through holes evenly distributed at equal intervals;

[0047] S4: mixing lithium carboxymethyl cellulose and carbon nanotubes with water according to a preset ratio to form a slurry, and mixing the slurry evenly by ball milling;

[0048] S5: Spreading the evenly mixed slurry on the surface of the second metal layer 3 by a scraper, so that the slurry penetrates into the through holes and fills the holes, so as to form a composite current collector with a conductor 4 provided in the through holes.

[0049] In the above, first, an insulating film body 1 with a preset thickness of 7μm is provided. Then, magnetron sputtering technology is used to form a first metal layer 2 on the upper and lower surfaces of the film body, respectively. These metal layers have a copper metal layer with a preset first thickness of 100nm. Subsequently, a second metal layer 3 of aluminum metal with a second thickness of 1μm is formed on the first metal layer 2 by an electroplating process. This process helps to increase the thickness of the metal layer and may improve the conductivity of the battery. Then, a laser process is used to punch holes along the upper and lower surfaces to form a plurality of through holes evenly distributed at equal intervals. The diameter of the through hole is 30μm, and its density is 5 / cm 2, these through holes provide space and provide channels for subsequent conductive agent filling. Next, the lithium carboxymethyl cellulose and carbon nanotubes are mixed with water in a preset ratio to form a slurry. The slurry is mixed evenly by ball milling to ensure that the materials therein are evenly mixed. Finally, the evenly mixed slurry is spread on the surface of the second metal layer 3 by a scraper. This process helps the slurry to penetrate into the through holes and fill the holes to form a composite current collector with a conductor 4 provided in the through holes. In this way, the combination of the above-mentioned multiple process steps, from the preparation of the insulating film body 1 to the formation of the through holes, and then to the final filling of the conductive agent, may play a key role in improving the performance and safety of the battery.

[0050] The above are only preferred implementations of the present utility model. The protection scope of the present utility model is not limited to the above embodiments. All technical solutions under the concept of the present utility model belong to the protection scope of the present utility model.

Claims

1. A composite current collector, characterized in that: It includes an intermediate layer and a metal layer; the intermediate layer is configured as an insulating film body, and the insulating film body is formed with an upper surface and a lower surface for the metal layer; the metal layer includes a first metal layer and a second metal layer, the first metal layer is formed on the upper surface and the lower surface, and the second metal layer is formed on the first metal layer; the composite current collector also includes a through hole penetrating the metal layer and the intermediate layer; and the through hole is filled with a conductor composed of a slurry mixed with a binder and a conductive agent.

2. The composite current collector according to claim 1, characterized in that: The insulating film is made of one of PET, PP and PI, and has a thickness ranging from 2 μm to 12 μm.

3. The composite current collector according to claim 1, characterized in that: The first metal layer is at least one of copper, aluminum, nickel, iron, chromium, titanium, molybdenum and cobalt, and has a thickness ranging from 10 nm to 1000 nm.

4. The composite current collector according to claim 3, characterized in that: The second metal layer is at least one of copper, aluminum, nickel, iron, chromium, titanium, molybdenum and cobalt, and has a thickness ranging from 500nm to 5000nm.

5. The composite current collector according to claim 4, characterized in that: The material of the second metal layer is different from that of the first metal layer.

6. The composite current collector according to claim 1, characterized in that: The diameter of the through holes ranges from 1 μm to 100 μm, and the distribution density ranges from 1 to 10,000 per m 2 .

7. The composite current collector according to claim 1, characterized in that: The binder is CMC-Li, which is used to supplement lithium into the conductor.

8. The composite current collector according to claim 1, characterized in that: The conductive agent material is a carbon material and a metal powder material. The carbon material includes carbon nanotubes, graphene, conductive carbon black, or graphite material. The metal powder includes gold, silver, platinum, copper, iron, nickel, or cobalt powdered metal material.

9. An electrode sheet, characterized in that: Comprising the composite current collector as described in any one of claims 1-8.

10. A lithium battery, characterized in that: Comprising the electrode sheet as claimed in claim 9.

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