Novel composite current collector and tab structure
By optimizing the composite current collector structure, direct welding of the electrode tab and the composite current collector was achieved, solving the processing bottleneck, reducing manufacturing costs, and improving the energy density of the battery cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-24
- Publication Date
- 2026-04-07
AI Technical Summary
The existing composite current collector and electrode tab connection method has processing bottlenecks, which leads to increased cell manufacturing costs and reduced energy density, and cannot effectively co-melt weld.
A novel composite current collector structure is designed, comprising a first metal layer, a first adhesive layer, a polymer layer, a second adhesive layer, and a second metal layer arranged sequentially from top to bottom. It is provided with welding slots, which allow the first metal layer and the second metal layer to be directly welded in the welding slots. The electrode tabs are connected to the composite current collector through the metal layer recessed in the welding slots.
It simplifies the production process, reduces manufacturing costs, avoids cell space loss, and improves cell energy density and processing convenience.
Smart Images
Figure CN224096693U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of lithium battery technology, and in particular relates to a novel composite current collector and electrode structure. Background Technology
[0002] With the continuous updating and development of lithium-ion battery technology, the application fields of lithium-ion batteries are also expanding. Consequently, the safety of battery cells is receiving increasing public attention. Lithium-ion battery safety accidents characterized by thermal failure following mechanical damage to the cell occur frequently, hindering the development of lithium-ion batteries. Solving the cell safety problem is a challenge the lithium battery industry must currently face. Often, improvements in the performance of the four main materials result in a loss of electrical performance and energy density in the cell. Furthermore, conventional cell safety protection methods can only delay thermal failure, but cannot completely solve the safety problems caused by mechanical damage to the cell, thus limiting their application. The composite current collector (Metal polymer film, MPF) adopts a three-layer sandwich structure of metal-polymer-metal, which can significantly reduce the thickness of the metal layer, resulting in a certain weight reduction and improving the weight energy density of the battery cell. At the same time, the thinner metal layer reduces the metal burrs generated when the battery cell is subjected to external mechanical damage, thereby reducing the risk of short circuit failure between the aluminum metal and the anode inside the battery cell. The main mechanical support layer of the composite current collector is polymer. Since polymer has better deformation and elongation than metal, it has a wider operating window in processing. Therefore, the composite current collector combines multiple advantages such as weight reduction, increased energy density, battery cell mechanical safety, and processing.
[0003] Currently, the bottleneck in the processing of composite current collectors in battery cells lies in the connection method with the tabs. Due to the presence of the polymer layer in the middle of the composite current collector, the tabs and current collectors cannot be effectively eutectic welded. The commonly used welding method is to connect the composite current collector and the tabs by using a metal foil transfer material. This solution increases the number of battery cell production steps, leading to increased battery cell manufacturing costs. In addition, the metal foil transfer material will leave welding marks, which cannot be squeezed or bent during battery cell processing, resulting in the loss of some battery cell housing space, that is, the loss of internal space of the battery cell and the reduction of battery cell energy density. Utility Model Content
[0004] This invention provides a novel composite current collector and tab structure, which can effectively solve the above-mentioned problems.
[0005] This utility model is implemented as follows:
[0006] A novel composite current collector includes a composite layer formed by a first metal layer, a first adhesive layer, a polymer layer, a second adhesive layer, and a second metal layer arranged sequentially from top to bottom. A welding groove is provided along one side of the composite layer, and the welding groove penetrates the first adhesive layer, the polymer layer, and the second adhesive layer. The first metal layer and the second metal layer form a welding area corresponding to the welding groove.
[0007] As a further improvement, at least one welding slot is provided.
[0008] As a further improvement, at least one of the first metal layer and the second metal layer is recessed into the weld groove.
[0009] As a further improvement, the first metal layer and the second metal layer form a weld or weld layer within the welding slot.
[0010] As a further improvement, both the first metal layer and the second metal layer are recessed into the welding slot, and the first metal layer and the second metal layer form a weld connection in the welding slot.
[0011] As a further improvement, the thickness of the first metal layer and the second metal layer is 0.5um to 5um; the thickness of the first adhesive layer and the second adhesive layer is 0.1um to 2um; and the thickness of the polymer layer is 1.5um to 10um.
[0012] As a further improvement, the total thickness of the first and second metal layers in the welding area is 1~8 μm.
[0013] As a further improvement, the first metal layer and the second metal layer are aluminum or copper layers; the first adhesive layer and the second adhesive layer are thermosetting adhesive layers.
[0014] As a further improvement, the dimensions of the welding slot are 18~28mm in length and 8~16mm in width.
[0015] A novel electrode structure includes the aforementioned composite current collector and electrode. The electrode is connected to the outside of a first metal layer or a second metal layer that is recessed inward in the welding area of the composite current collector, or is disposed between the first metal layer and the second metal layer in the welding slot, thereby realizing the electrical connection between the first metal layer, the second metal layer and the electrode.
[0016] The beneficial effects of this utility model are as follows: By optimizing the composite current collector structure, this application obtains welding sites for pure metal tabs by locally eliminating the polymer layer in the composite current collector. The pure metal sites can be directly welded to the tabs without the need for external aluminum foil transfer, simplifying the product structure and production process, and reducing manufacturing costs. In addition, it avoids the problem of welding marks left by the transfer metal foil, which would prevent the cell from being squeezed and bent during the cell processing, resulting in the loss of some cell housing space and thus the loss of internal space of the cell. The improvement increases the energy density of the cell. Overall, it has achieved a significant improvement and performance enhancement compared to existing composite current collectors, making it easier to produce and process, and facilitating the promotion and application of the product. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of a novel composite current collector according to an embodiment of the present invention;
[0019] Figure 2 This is a schematic diagram of another embodiment of a novel composite current collector according to this utility model;
[0020] Figure 3 This is a schematic diagram of another embodiment of a novel composite current collector according to this utility model;
[0021] Figure 4 This is a schematic diagram of another embodiment of a novel composite current collector according to this utility model;
[0022] Figure 5 This is a schematic diagram of another embodiment of a novel composite current collector according to this utility model;
[0023] Figure 6 This is a schematic diagram of another embodiment of a novel composite current collector according to this utility model;
[0024] Figure 7 This is a cross-sectional view provided by an embodiment of a novel composite current collector according to this utility model;
[0025] Figure 8 This is a schematic diagram of a novel electrode structure embodiment provided by this utility model;
[0026] Figure 9This is a schematic diagram of another embodiment of a novel electrode structure according to this utility model;
[0027] Figure 10 This is a schematic diagram of another embodiment of a novel electrode structure according to this utility model;
[0028] Figure 11 This is a schematic diagram of another embodiment of a novel electrode structure according to this utility model;
[0029] Figure 12 This is a schematic diagram of another embodiment of a novel electrode structure according to this utility model;
[0030] Figure 13 This is a schematic diagram of another embodiment of a novel electrode structure according to this utility model;
[0031] Figure 14 This is a cross-sectional view provided by an embodiment of a novel electrode structure of this utility model;
[0032] Figure 15 This is a cross-sectional view of another embodiment of a novel electrode structure of this utility model;
[0033] Figure 16 This is a cross-sectional view of another embodiment of a novel electrode structure of this utility model.
[0034] Figure label:
[0035] First metal layer 1; First adhesive layer 2; Polymer layer 3; Second adhesive layer 4; Second metal layer 5; Welding slot 6; Welding area 7; Weld 71; Weld layer 72; Tab 8. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.
[0037] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0038] In the description of this utility model, the terms "upper", "middle", "side", "side", "upper side", "end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0039] Reference Figure 1-7 As shown, a novel composite current collector includes a composite layer formed by a first metal layer 1, a first adhesive layer 2, a polymer layer 3, a second adhesive layer 4, and a second metal layer 5 arranged sequentially from top to bottom. A welding groove 6 is provided along one side of the composite layer. The welding groove 6 penetrates the first adhesive layer 2, the polymer layer 3, and the second adhesive layer 4. The first metal layer 1 and the second metal layer 5 form a welding area 7 corresponding to the welding groove 6.
[0040] This application provides a welding slot 6 along one side of the composite layer. The welding slot 6 penetrates the first adhesive layer 2, the polymer layer 3, and the second adhesive layer 4, which allows a welding area 7 to be formed at the location of the welding slot 6. The first metal layer 1 and the second metal layer 5 on the upper and lower sides can be directly recessed inward to achieve electrical connection. The recessed area on one side is then welded to the tab 8, or the tab 8 is inserted between the first metal layer 1 and the second metal layer 5, and then the tab 8 is electrically connected to the first metal layer 1 and the second metal layer 5 on both sides through welding.
[0041] Furthermore, at least one welding slot 6 is provided.
[0042] Since the single-layer metal current collector of the composite current collector is only about 1µm thick and the double-layer is about 2µm thick, compared with the conventional metal foil of 10µm thickness, the ability to transport electrons will be weakened. Therefore, it is necessary to increase the number of tabs to improve the charge and discharge rate of the cell, which is suitable for fast charge and discharge requirements.
[0043] Welding slots 6 are typically located at at least one of the following locations on one side edge of the composite layer: 1 / 3, 1 / 2, or 2 / 3; or in more cases, they are evenly distributed along the side edge.
[0044] Furthermore, at least one of the first metal layer 1 and the second metal layer 5 is recessed into the welding slot 6.
[0045] At least one side is recessed inward so that the first metal layer 1 and the second metal layer 5 on both sides are connected or connected to the tab 8 in the middle; one side of the metal layer may be parallel to the surface and the other side is recessed inward; both sides may be recessed inward, and the degree of recess on both sides may be the same or different. If the recess is the same, it is easier to process; or neither side of the first metal layer 1 and the second metal layer 5 may be recessed, in which case the tab 8 is set between the first metal layer 1 and the second metal layer 5, and the thickness of the tab 8 is exactly the distance between the first metal layer 1 and the second metal layer 5.
[0046] Furthermore, the first metal layer 1 and the second metal layer 5 form a weld 71 or a weld layer 72 within the welding slot 6.
[0047] Weld 71 is used to insert tab 8, and to set tab 8 between the first metal layer 1 and the second metal layer 5 to form an electrical connection; weld layer 72 makes the first metal layer 1 and the second metal layer 5 form an electrical connection. Tab 8 is set on the outside of the first metal layer 1 or the second metal layer 5 and is set on the recessed side to reduce space occupation and improve the energy density of the battery cell.
[0048] Furthermore, both the first metal layer 1 and the second metal layer 5 are recessed into the welding slot 6, and the first metal layer 1 and the second metal layer 5 form a weld layer 72 connected within the welding slot 6.
[0049] This method is convenient for processing.
[0050] Furthermore, the thickness of the first metal layer 1 and the second metal layer 5 is 0.5um to 5um; the thickness of the first adhesive layer 2 and the second adhesive layer 4 is 0.1um to 2um; and the thickness of the polymer layer 3 is 1.5um to 10um.
[0051] Furthermore, the total thickness of the first metal layer 1 and the second metal layer 5 in the welding area 7 is 1~8 μm.
[0052] Furthermore, the first metal layer 1 and the second metal layer 5 are aluminum or copper layers; the first adhesive layer 2 and the second adhesive layer 4 are thermosetting adhesive layers.
[0053] Furthermore, the dimensions of the welding slot 6 are 18~28mm in length and 8~16mm in width.
[0054] Reference Figure 8-16 As shown, a novel electrode structure includes the aforementioned composite current collector and electrode 8. The electrode 8 is connected to the outside of the first metal layer 1 or the second metal layer 5 recessed inward in the welding area 7 of the composite current collector, or is disposed between the first metal layer 1 and the second metal layer 5 in the welding slot 6, thereby realizing the electrical connection between the first metal layer 1, the second metal layer 5 and the electrode 8.
[0055] The connection between the tab 8 and the composite current collector can be either a direct connection between the first metal layer 1 and the second metal layer 5, with the tab 8 connected to one side of the composite layer, or a placement of the tab 8 between the first metal layer 1 and the second metal layer 5, forming an electrical connection between the three.
[0056] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A novel composite current collector, characterized in that, The composite layer comprises a first metal layer, a first adhesive layer, a polymer layer, a second adhesive layer, and a second metal layer arranged sequentially from top to bottom. A welding groove is provided along one side of the composite layer, and the welding groove penetrates the first adhesive layer, the polymer layer, and the second adhesive layer. The first metal layer and the second metal layer form a welding area corresponding to the welding groove.
2. The novel composite current collector according to claim 1, characterized in that, There is at least one welding slot.
3. The novel composite current collector according to claim 1, characterized in that, At least one of the first metal layer and the second metal layer is recessed into the weld groove.
4. A novel composite current collector according to claim 3, characterized in that, The first metal layer and the second metal layer form a weld or weld layer in the welding slot.
5. A novel composite current collector according to claim 1, 3, or 4, characterized in that, Both the first metal layer and the second metal layer are recessed into the welding slot, and the first metal layer and the second metal layer form a weld connection in the welding slot.
6. A novel composite current collector according to claim 1, characterized in that, The thickness of the first metal layer and the second metal layer is 0.5 μm to 5 μm; the thickness of the first adhesive layer and the second adhesive layer is 0.1 μm to 2 μm; and the thickness of the polymer layer is 1.5 μm to 10 μm.
7. A novel composite current collector according to claim 1, 3, 4 or 6, characterized in that, The total thickness of the first and second metal layers in the welding area is 1~8 μm.
8. A novel composite current collector according to claim 1 or 6, characterized in that, The first metal layer and the second metal layer are aluminum or copper layers; the first adhesive layer and the second adhesive layer are thermosetting adhesive layers.
9. A novel composite current collector according to claim 1, 2, 3 or 4, characterized in that, The dimensions of the welding slot are 18~28mm in length and 8~16mm in width.
10. A novel electrode structure, characterized in that, The device includes the composite current collector and the tab as described in any one of claims 1-9, wherein the tab is connected to the outside of the first metal layer or the second metal layer recessed inward in the welding area of the composite current collector, or is disposed between the first metal layer and the second metal layer in the welding slot, thereby realizing the electrical connection between the first metal layer, the second metal layer and the tab.