Bipolar current collector, bipolar electrode and battery
By setting a blank base film region in the bipolar current collector and adopting a Z-shaped stacking method, the problem of metal burrs in the preparation process of bipolar current collectors is solved, achieving efficient and safe battery production and reducing costs and risks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2026-04-14
AI Technical Summary
Existing bipolar current collectors require slicing and punching processes during fabrication, which can easily lead to metal burrs that cause battery self-discharge and short circuits, and are also costly.
A bipolar current collector is designed using a polymer thin film substrate strip, with alternating positive and negative active regions and a blank substrate region in between. The cell is fabricated by Z-shaped stacking, eliminating the slicing and stamping processes, and using aluminum and copper layers as the positive and negative metal layers.
It improves production efficiency, reduces equipment costs and the occurrence of metal burrs, avoids battery self-discharge and short circuits, and increases battery safety.
Smart Images
Figure CN224123347U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, specifically to a bipolar current collector, a bipolar electrode, and a battery. Background Technology
[0002] Lithium-ion batteries have rapidly gained a foothold in the global new energy market due to their high energy density, good cycle stability, and environmental friendliness, and are now used in a wide range of fields, from small 3C products to electric vehicles and ships. To further expand their advantages and reduce battery usage costs, it is necessary to optimize the design of battery materials, structure, and other aspects.
[0003] As a crucial component of lithium-ion batteries, current collectors, particularly metal foil current collectors, currently account for approximately 15% of battery weight, consuming significant costs and hindering further improvements in battery energy density. Functional metal foil current collectors are three-layer structures using an insulating polymer film as the supporting material: a metal conductive layer, a polymer support layer, and another metal conductive layer. Based on functional metal foil current collectors, bipolar current collectors have been developed. Current bipolar current collectors are composite bipolar current collectors obtained by coating both positive and negative electrode materials on either side of the supporting material (the intermediate layer) using methods such as magnetron sputtering and multiple vapor deposition. After the bipolar current collector is fabricated into electrode sheets, it is wound into a battery cell using a staggered overlapping method. This process requires slicing and punching, which can easily result in metal burrs. These burrs can lead to high self-discharge and short circuits in the battery. Utility Model Content
[0004] The purpose of this invention is to address the above-mentioned problems by providing a bipolar current collector that does not require slicing or stamping processes, as well as the electrodes and batteries made from it.
[0005] To achieve the above objectives, the technical solution provided by this utility model is as follows:
[0006] The first aspect of this application provides a bipolar current collector, comprising a polymer thin film base material strip, wherein the polymer thin film base material strip is provided with a row of positive electrode active regions and negative electrode active regions.
[0007] The positive and negative active regions are alternately arranged; there is a blank base film region between adjacent positive and negative active regions; the end of the positive active region is the positive tab region and the end of the negative active region is the negative tab region.
[0008] To optimize the above technical solution, the specific measures also include:
[0009] The positive electrode active region and the positive electrode tab region are formed by covering a positive electrode metal layer on a polymer film; the negative electrode active region and the negative electrode tab region are formed by covering a negative electrode metal layer on a polymer film.
[0010] The positive electrode metal layer is an aluminum layer; the negative electrode metal layer is a copper layer.
[0011] Furthermore, the positive electrode active region and the negative electrode active region have the same shape and size.
[0012] Furthermore, the width of the blank base film area is 3-100mm; all blank base film areas have the same width.
[0013] The positive electrode ear region and the positive electrode active region are an integral structure, and the negative electrode ear region and the negative electrode active region are an integral structure; the positive electrode ear region and the negative electrode ear region are cut to form the positive electrode ear end and the negative electrode ear end.
[0014] As a preferred embodiment, all positive electrode tips are located at the same position on the positive electrode active region; all negative electrode tips are located at the same position on the negative electrode active region.
[0015] A second aspect of this application provides a bipolar electrode comprising the aforementioned bipolar current collector.
[0016] A third aspect of this application provides a battery comprising the aforementioned bipolar electrode and two separators, wherein the separators have an elongated shape matching the bipolar current collector, the two separators are respectively located on the front and rear sides of the bipolar electrode, and the bipolar electrode and the separators on the front and rear sides are stacked together in a Z-shape along the blank base film area of the bipolar current collector to form a cell pack.
[0017] The outermost electrode region of the battery pack corresponds to the negative electrode active region of the bipolar current collector, and a separator is covered on the outermost electrode region.
[0018] Compared with the prior art, the beneficial effects of this utility model are:
[0019] This invention's bipolar current collector, by setting a blank base film area between the positive and negative active regions, can be rapidly fabricated into a battery cell using a Z-shaped stacking method. This eliminates the traditional positive and negative electrode slicing and stamping processes, reducing equipment costs, saving production time, and improving production efficiency. It also significantly reduces the occurrence of metal burrs, avoiding self-discharge and short circuits caused by metal burrs in the battery. Furthermore, since the blank base film area is not coated with active material, it does not pose a lithium plating risk compared to battery cells made by winding, thus offering a greater safety advantage. Attached Figure Description
[0020] Figure 1 : Schematic diagram of the structure of the bipolar current collector of this utility model.
[0021] Figure 2 : A schematic diagram of the structure of the bipolar current collector of this utility model (after cutting the tabs).
[0022] Figure 3 : Schematic diagram of two bipolar current collectors.
[0023] Figure 4 : Schematic diagram of Z-shaped stacked pieces.
[0024] In the figure: 1-positive active region, 2-negative active region, 3-blank base film region, 4-positive tab region, 5-negative tab region, 6-positive tab end, 7-negative tab end, 8-pair of tangents, 9-bipolar current collector, 10-septum. Detailed Implementation
[0025] The present invention will be further described in detail below through embodiments, but it should not be construed as the scope of the present invention being limited to the following embodiments. All technologies implemented based on the present invention fall within the scope of the present invention.
[0026] In the description of this utility model, it should also be noted that:
[0027] The orientations or positional relationships described herein are based on the relationships shown in the accompanying drawings and are only for the purpose of facilitating the description of this utility model and simplifying the description. They are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0028] This invention provides a bipolar current collector, such as... Figure 1 As shown, it includes a polymer thin film base material strip, on which a row of positive electrode active regions 1 and negative electrode active regions 2 are provided;
[0029] The positive electrode active region 1 and the negative electrode active region 2 are alternately arranged; there is a blank base film region 3 between adjacent positive electrode active regions 1 and negative electrode active regions 2; the end of the positive electrode active region 1 is the positive electrode tab region 4, and the end of the negative electrode active region 2 is the negative electrode tab region 5.
[0030] Positive electrode active region 1 and positive electrode tab region 4 are positive electrode metal layers covered on a polymer film; negative electrode active region 2 and negative electrode tab region 5 are negative electrode metal layers covered on a polymer film.
[0031] The positive electrode metal layer is an aluminum layer; the negative electrode metal layer is a copper layer.
[0032] In some implementations, the positive electrode active region 1 and the negative electrode active region 2 have the same shape and size.
[0033] In some implementations, all blank base film regions 3 have the same width.
[0034] The positive electrode ear region 4 and the positive electrode active region 1 are integral structures, and the negative electrode ear region 5 and the negative electrode active region 2 are integral structures; the positive electrode ear region 4 and the negative electrode ear region 5 are cut to form the positive electrode ear tip 6 and the negative electrode ear tip 7, as shown below. Figure 2 As shown.
[0035] All positive electrode tips 6 are located at the same position on the positive electrode active region 1; all negative electrode tips 7 are located at the same position on the negative electrode active region 2.
[0036] In the preparation of the bipolar current collector of this invention, a positive electrode metal layer and a negative electrode metal layer are respectively covered on a thin film base material strip at intervals. The positive electrode active region 1 and the positive electrode tab region 4 can be prepared simultaneously, and the negative electrode active region 2 and the negative electrode tab region 5 can be prepared simultaneously. Then, the tabs are laser-cut, and the waste areas of the edge portions of the positive electrode metal layer and the negative electrode metal layer along the width direction are removed to form the bipolar current collector 9.
[0037] The positive electrode metal layer is typically an aluminum metal layer, and the negative electrode metal layer is typically a copper metal layer. The positive and negative electrode metal layers can be fabricated using various methods such as magnetron sputtering and multiple evaporation deposition. The blank base film region 3 remains untreated and is still a polymer thin film substrate.
[0038] Specifically, the width of the blank base film region 3 of this utility model can be 3-100mm; the thickness of the positive electrode metal layer and the negative electrode metal layer can be 0.2-0.8μm; the length and width of the positive electrode active region 1 and the negative electrode active region 2 are determined by the required cell size, and the width can generally be 50-1000mm, and the length can be set as needed.
[0039] To improve efficiency in the preparation of bipolar current collectors, spaced positive and negative metal layers can be formed on a single polymer film substrate material strip corresponding to the widths of the two bipolar current collectors of this invention. The middle portion corresponds to the positive electrode tab region 4 and the negative electrode tab region 5 of the two bipolar current collectors. Then, the strip is cut in half from the middle of the positive electrode tab region 4 and the negative electrode tab region 5. Figure 3 As shown, the electrode tabs are then formed by laser die-cutting, thus forming two bipolar current collectors at once.
[0040] When using this bipolar current collector to prepare a battery, a corresponding active material is coated on the surface of the bipolar current collector 9, and after drying, a bipolar electrode is obtained. Two separators 10 with shapes matching those of the bipolar current collector 9 are placed on the front and back sides of the bipolar electrode formed by the bipolar current collector 9, respectively. The bipolar electrode and the separators 10 on both sides are then stacked in a Z-shape along the blank base film region 3 of the bipolar current collector 9 to form a battery cell pack. Figure 4As shown; finally, the positive and negative electrode adapter pieces are welded to the positive and negative electrode tabs 7 by resistance welding, which is the same as the adapter welding steps of ordinary batteries.
[0041] In some embodiments, the outermost electrode region of the battery pack corresponds to the negative electrode active region 2 of the bipolar current collector, and a separator 10 is covered on the outermost electrode region.
[0042] This invention's bipolar current collector eliminates the need for cutting the positive electrode active region 1 and the negative electrode active region 2. It only requires Z-shaped stacking to form a cell pack containing both positive and negative electrodes, thus eliminating the slicing and stamping processes in cell manufacturing, saving equipment costs, production time, and improving production efficiency. Because the positive electrode active region 1 and the negative electrode active region 2 are not sliced or stamped, metal burrs are avoided, reducing the battery's short-circuit rate. Furthermore, since the blank base film region 3 between the positive electrode active region 1 and the negative electrode active region 2 is not coated with active material, compared to cells manufactured by winding, this area does not pose a risk of lithium plating.
[0043] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the present utility model's technical solution and based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model's technical solution.
Claims
1. A bipolar current collector, characterized in that: It includes a polymer thin film base material strip, on which a row of positive electrode active regions and negative electrode active regions are provided; The positive and negative active regions are alternately arranged; there is a blank base film region between adjacent positive and negative active regions; the end of the positive active region is the positive tab region and the end of the negative active region is the negative tab region.
2. The bipolar current collector according to claim 1, characterized in that: The positive electrode active region and the positive electrode tab region are formed by covering a positive electrode metal layer on a polymer film; the negative electrode active region and the negative electrode tab region are formed by covering a negative electrode metal layer on a polymer film.
3. The bipolar current collector according to claim 2, characterized in that: The positive electrode metal layer is an aluminum layer; the negative electrode metal layer is a copper layer.
4. The bipolar current collector according to claim 1, characterized in that: The positive electrode active region and the negative electrode active region have the same shape and size.
5. The bipolar current collector according to claim 1, characterized in that: The width of the blank base film area is 3-100mm; all blank base film areas have the same width.
6. The bipolar current collector according to claim 1, characterized in that: The positive electrode ear region and the positive electrode active region are an integral structure, and the negative electrode ear region and the negative electrode active region are an integral structure; the positive electrode ear region and the negative electrode ear region are cut to form the positive electrode ear end and the negative electrode ear end.
7. The bipolar current collector according to claim 6, characterized in that: All positive electrode tips are located at the same position on the positive electrode active region; all negative electrode tips are located at the same position on the negative electrode active region.
8. A bipolar electrode, characterized in that: It includes the bipolar current collector as described in any one of claims 1-7.
9. A battery, characterized in that: The battery pack includes the bipolar electrode as described in claim 8 and two separators, wherein the separators have an elongated shape that matches the bipolar current collector, the two separators are located on the front and rear sides of the bipolar electrode respectively, and the bipolar electrode and the separators on the front and rear sides are stacked together in a Z-shape along the blank base film area of the bipolar current collector to form a battery pack.
10. The battery according to claim 9, characterized in that: The outermost electrode region of the battery pack corresponds to the negative electrode active region of the bipolar current collector, and a separator is covered on the outermost electrode region.