Pole piece and wound battery
The electrode sheet with conductive adhesive layers on both sides addresses the internal resistance and connection issues in cylindrical batteries, improving conductivity and safety by ensuring better adhesion and contact between the electrode tabs and the current collector.
Patent Information
- Application Number
- CN202421796310.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-26
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-07-26
AI Technical Summary
The electric conduction path of the inner ring of the cylindrical battery has a long electric conduction path and large internal resistance of the battery. The electrode ear is prone to deformation and produces debris and causes a risk of short circuit, and the electrode ear and the current collecting plate are poorly welded.
The first and second surfaces of the electrode region of the electrode sheet are provided with conductive adhesive layers, and the current collector of the electrode ear region is bonded to the electrode ear region, reducing the current transmission path, and enhancing the bonding between the electrode ear and the current collecting disk and current conduction.
It reduces the probability of the occurrence of extreme ear debris, reduces the internal resistance and short circuit risk of battery, and improves the safety performance and production pass rate of the battery.
Smart Images
Figure CN223108895U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of batteries, in particular to a pole piece and a wound battery. Background Art
[0002] Due to the requirements of liquid injection and explosion prevention of cylindrical batteries, a part of the earless area will be set in the inner circle of the cylindrical battery to facilitate the flattening of the outer ear inward, and the ear area will not cover the central area of the cylindrical battery; however, this design will result in a long conduction path in the inner circle of the cylindrical battery and a large internal resistance of the battery. On the other hand, when preparing the winding core of the cylindrical battery, a flattening process will be carried out on the full ear. The roller pressure required for flattening the ear is relatively large, which may cause deformation of the ear and the generation of ear debris. The generation of ear debris may further lead to the risk of short circuit of the later-stage battery core. In addition, since there are many small ears during ear flattening, there may be irregular overlap of small ears and inconsistent radial slopes, which easily leads to poor contact during the welding of the current collector plate. Summary of the Utility Model
[0003] In order to overcome the disadvantages and deficiencies in the prior art, the purpose of the utility model is to provide a pole piece and a wound battery, which solve the problems of large internal resistance of the wound battery in the inner circle, ear debris caused by the flattening process, and poor welding between the ear and the current collector plate, and improve the qualification rate and safety performance of the wound battery.
[0004] The purpose of the utility model is realized by the following technical solutions:
[0005] A pole piece includes a current collector, and a conductive adhesive layer and an active material layer disposed on the current collector. Along the width direction of the current collector, the current collector includes an adjacent empty foil area and an active material area. The active material layer is disposed in the active material area. The empty foil area includes an ear area. The pole piece includes opposite first and second surfaces. At least part of the current collector is provided with the conductive adhesive layer on the first and second surfaces of the ear area.
[0006] In one embodiment, the conductive adhesive layer on the first surface of the ear area is a first conductive adhesive layer, and the conductive adhesive layer on the second surface of the ear area is a second conductive adhesive layer. The thicknesses of the first conductive adhesive layer and the second conductive adhesive layer are the same or different.
[0007] In one embodiment, the thickness of the first conductive adhesive layer is D1, the thickness of the active material layer is D2, and D1 / D2 = 1 / 7 - 1 / 30; and / or, the thickness of the second conductive adhesive layer is D3, the thickness of the active material layer is D2, and D3 / D2 = 1 / 5 - 1 / 30.
[0008] In one embodiment, the thickness of the first conductive adhesive layer is D1, and the thickness of the second conductive adhesive layer is D3. The ranges of D1 and D3 are 0.5 - 20 μm.
[0009] In one embodiment, when the electrode sheet is wound to form a wound battery, the second side of the electrode sheet is wound in the direction of covering the first side of the electrode sheet, and the second conductive adhesive layer can be bonded to the current collector plate; the thickness of the first conductive adhesive layer is D1, and the thickness of the second conductive adhesive layer is D3, and D3 > D1.
[0010] In one embodiment, along the width direction of the current collector, the empty foil area further includes a spacer area, and the empty foil area is composed of the tab area and the spacer area; the spacer area is arranged between the tab area and the active material area, and conductive adhesive layers are provided on both the first side and the second side of the current collector in the spacer area.
[0011] In one embodiment, the current collector has a length direction, and the electrode sheet includes a plurality of tabs. Along the length direction of the current collector, the plurality of tabs are spaced apart and distributed in the tab area.
[0012] The present utility model further provides a wound battery, which includes a wound battery cell, and the wound battery cell is wound after being compounded with a separator and the electrode sheet as described above.
[0013] In one embodiment, the wound battery further includes a current collector plate, and the conductive adhesive layer on one side thereof can be bonded to the current collector plate.
[0014] The beneficial effects of the present utility model are as follows: By providing conductive adhesive layers on both the first side and the second side of the tab area of the current collector, on the one hand, the tabs can be bonded to the current collector in the tabless area at the center of the wound battery, reducing the current transmission path in the tabless area and lowering the internal resistance of the battery; on the other hand, since the tabs coated with the conductive adhesive layer are more flexible and connective, the probability of some tabs being crushed during kneading is reduced, and the risks of battery short - circuit and self - discharge are decreased; meanwhile, the conductive adhesive layer enables the tabs to be bonded and conduct electricity with each other during kneading, and can be bonded and conduct electricity with the current collector plate, making the contact between the current collector plate and the tabs more sufficient during welding and enhancing the overall conductive ability of the battery. Overall, the safety performance and production qualification rate of the product are improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present utility model, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.
[0016] Figure 1 is a schematic structural view of a pole piece before cutting according to an embodiment of the present utility model;
[0017] Figure 2 is Figure 1 a schematic structural view after cutting;
[0018] Figure 3 is a schematic structural view of a pole piece after cutting according to another embodiment of the present utility model;
[0019] Figure 4 is a side view of the pole piece;
[0020] Figure 5 is a schematic structural view of a wound pole piece with a conductive adhesive layer according to an embodiment of the present utility model.
[0021] In the figure: 100, pole piece; 1A, first side; 1B, second side; 1C, starting end; 1, current collector; 11, empty foil area; 11A, tab area; 11B, spacer area; 111, tab; 12, active material area; 2, conductive adhesive layer; 21, first conductive adhesive layer; 22, second conductive adhesive layer; 3, active material layer. Specific embodiments
[0022] Next, specific embodiments of the present utility model will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. Based on the description of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present utility model.
[0023] In the description of the present utility model, unless otherwise clearly defined and limited, terms such as "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.
[0024] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present utility model is usually placed during use. It is only for the convenience of description and simplification of the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model.
[0025] The terms "first", "second", "third", etc. are only used to distinguish components with similar attributes, rather than indicating or implying relative importance or a specific order.
[0026] The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion. In addition to the elements listed, it may also include other elements not specifically listed.
[0027] The present utility model provides a pole piece 100, as Figures 1 to 5 shown, which includes a current collector 1, a conductive adhesive layer 2 and an active material layer 3 provided on the current collector 1. Along the width direction W of the current collector 1, the current collector 1 includes an adjacent empty foil area 11 and an active material area 12. An active material layer 3 is provided in the active material area 12. The empty foil area 11 includes a tab area 11A. The pole piece 100 includes opposite first surface 1A and second surface 1B. At least part of the current collector 1 is provided with a conductive adhesive layer 2 on the first surface 1A and the second surface 1B of the tab area 11A. In this embodiment, by providing the conductive adhesive layer 2 on both the first surface 1A and the second surface 1B of the tab area 11A of the current collector 1, that is, on both sides of the current collector 1 along the thickness direction D, on the one hand, it can bond the tab 111 to the current collector 1 in the tabless area (not shown) at the center of the wound battery, reduce the current transmission path in the tabless area, and reduce the internal resistance of the battery; on the other hand, it makes the contact between the tabs 111 more firm, overcomes the risk of internal short circuit caused by debris of the tabs 111, and at the same time enhances the bond between the tabs 111 and the current collector plate (not shown), increases the current conduction between the tabs 111 and the current collector plate, and improves the qualification rate and safety performance of the wound battery. Among them, the current collector 1 is a foil material, and the foil material is generally aluminum foil (positive pole piece) and copper foil (negative pole piece). The conductive adhesive layer 2 is provided on the surface of the foil material to obtain the required pole piece 100; the current collector 1 is provided with an active material layer 3 on the first surface 1A and / or the second surface 1B of the active material area 12.
[0028] As an implementation manner, as Figure 4 shown, the conductive adhesive layer 2 located on the first surface 1A of the tab area 11A is the first conductive adhesive layer 21, and the conductive adhesive layer 2 located on the second surface 1B of the tab area 11A is the second conductive adhesive layer 22. The thicknesses of the first conductive adhesive layer 21 and the second conductive adhesive layer 22 are the same or different.
[0029] As an implementation manner, as Figure 4As shown, the thickness of the first conductive adhesive layer 21 is D1, the thickness of the active material layer 3 is D2, and D1 / D2 = 1 / 7 - 1 / 30, or D1 / D2 = 1 / 10 - 1 / 25, or D1 / D2 = 1 / 15 - 1 / 20; and / or, the thickness of the second conductive adhesive layer 22 is D3, the thickness of the active material layer 3 is D2, and D3 / D2 = 1 / 5 - 1 / 30, or D3 / D2 = 1 / 8 - 1 / 25, or D3 / D2 = 1 / 10 - 1 / 20, or D3 / D2 = 1 / 13 - 1 / 17. Wherein, when the active material layers 3 are arranged on both sides of the active material region 12 of the current collector 1, the thicknesses of the active material layers 3 on both sides may be the same or different; when the thicknesses of the active material layers 3 on both sides are different, the thickness of the thinner active material layer 3 is used as the standard for comparison with the thickness of the conductive adhesive layer 2. (Or directly default that the thicknesses of the active material layers 3 on both sides are the same)
[0030] As an implementation manner, as Figure 4 shown, the thickness of the first conductive adhesive layer 21 is D1, the thickness of the second conductive adhesive layer 22 is D3, and the ranges of D1 and D3 are 0.5 - 20 μm, or 1 - 15 μm, or 3 - 10 μm, or 5 - 8 μm.
[0031] As an implementation manner, when the electrode sheet 100 is wound to form a wound battery, the second side 1B of the electrode sheet 100 is wound toward the direction of covering the first side 1A of the electrode sheet 100, so that both the first conductive adhesive layer 21 and the second conductive adhesive layer 22 can be used for internal bonding between the tab ears 111, and the second conductive adhesive layer 22 can be directly bonded to the current collecting plate to increase the current conduction between the tab ears 111 and the current collecting plate, and improve the qualification rate and safety performance of the wound battery.
[0032] As an implementation manner, as Figure 4 shown, the thickness of the first conductive adhesive layer 21 is D1, the thickness of the second conductive adhesive layer 22 is D3, D3 > D1, the second conductive adhesive layer 22 is connected to the current collecting plate, the hardness of the current collecting plate is greater than that of the current collector 1, and stronger adhesiveness is required. The second conductive adhesive layer 22 is set thicker to meet the bonding requirement with the current collecting plate.
[0033] As an implementation manner, as Figure 1 and Figure 2 shown, along the width direction W of the current collector 1, the empty foil region 11 further includes a spacer region 11B, and the empty foil region 11 is composed of a tab ear region 11A and a spacer region 11B; the spacer region 11B is arranged between the tab ear region 11A and the active material region 12 and is adjacent to the tab ear region 11A and the active material region 12. The current collector 1 is provided with conductive adhesive layers 2 on both the first side 1A and the second side 1B of the spacer region 11B for fixing the separator, preventing the separator from loosening after repeated charging and discharging of the battery cell, reducing or lowering the risk of short circuit of the battery cell, and improving the safety performance of the battery cell. Of course, asFigure 3 As shown, the spacer 11B may not be provided with the conductive adhesive layer 2. By providing the spacer 11B, during the process of die-cutting the tab area 11A to form the tabs 111, it is convenient for die-cutting alignment, and the usage amount of the conductive adhesive is reduced during mass production.
[0034] As an implementation manner, as Figure 2 and Figure 3 shown, the electrode sheet 100 has a length direction L. The electrode sheet 100 includes a plurality of tabs 111. Along the length direction L of the electrode sheet 100, the plurality of tabs 111 are spaced apart and distributed in the tab area 11A. The plurality of tabs 111 are formed by cutting the electrode sheet 100 in the tab area 11A. Among them, along the length direction L of the electrode sheet 100, the electrode sheet 100 has a winding starting end 1C. On the side of the electrode sheet 100 close to the starting end 1C, no tabs 111 are provided. After winding, a wound battery cell with a tabless inner circle area is formed (as Figure 5 ), to avoid the tabs 111 at the inner circle position blocking the liquid injection port (not shown) when the tabs 111 are flattened; and conductive adhesive layers 2 are provided on both side surfaces of the tabs 111, so that during the flattening process of the tabs 111, they can be bonded to the current collector 1 in the tabless area, and the internal resistance can be reduced.
[0035] As an implementation manner, the conductive adhesive layer 2 is obtained by coating or spraying in the tab area 11A and the spacer 11B of the electrode sheet 100.
[0036] As an implementation manner, the conductive adhesive layer 2 is prepared from a conductive polymer material, has a certain adhesiveness, and at the same time has electrical conductivity.
[0037] The present utility model also provides a wound battery. The wound battery includes a wound battery cell (as Figure 5 shown), and the wound battery cell is wound after being laminated with a separator (not shown) and the electrode sheet 100 as described above, and the tabs 111 after winding are flattened; the tabs 111 coated with the conductive adhesive layer 2 are more flexible and connective, reducing the probability of some tabs 111 being crushed during flattening, reducing the generation of tab debris, reducing the risk of battery short circuit and self-discharge, thereby eliminating the impact on product quality, and also better improving the product qualification rate and safety performance.
[0038] As an implementation manner, the wound battery further includes a current collector plate, which is connected to the wound battery cell. Specifically, the current collector plate is connected to the tab 111 of the wound battery cell. When the electrode sheet 100 is wound to form a wound battery cell and the second side 1B of the electrode sheet 100 is wound toward the first side 1A that wraps the electrode sheet 100, the second conductive adhesive layer 22 of the tab 111 can be directly bonded to the current collector plate; when the electrode sheet 100 is wound to form a wound battery cell and the first side 1A of the electrode sheet 100 is wound toward the second side 1B that wraps the electrode sheet 100, the first conductive adhesive layer 21 of the tab 111 can be directly bonded to the current collector plate. The two-sided conductive adhesive layer 2 of the electrode sheet 100 can, on the one hand, bond the tab 111 to the current collector in the tabless area, reduce the current transmission path in the tabless area, lower the internal resistance of the battery, and can also enhance the bond between the tab 111 and the current collector plate, increasing the current conduction between the tab 111 and the current collector plate. After the conductive adhesive layer 2 in the tab area 11 is bonded to the current collector plate, the tab 111 is further welded to the current collector plate; this makes the contact between the current collector plate and the tab 111 more sufficient during welding, enhancing the current conduction effect.
[0039] When the electrode sheet 100 of the present utility model is made into a wound battery cell, it is conducive to the full-tab conductive contact. The electrode sheet 100 includes a positive electrode sheet and a negative electrode sheet. The positive electrode, the negative electrode sheet, and the separator are wound together in a certain order to form a cylindrical structure of the battery cell, that is, a wound battery cell.
[0040] The wound battery can be obtained by the following steps:
[0041] 1. When applying the active material to the electrode sheet, at the same time, apply the conductive adhesive to the blank foil area 11 of the electrode sheet; the conductive adhesive may not be completely applied to the blank foil area 11, that is, there is a spacer area 11B between the tab area 11A and the active material area 12, and the spacer area 11B may or may not be coated with the conductive adhesive; perform tab die-cutting on the coated electrode sheet 100 to obtain the tab 111, so that the tab 111 is coated with the conductive adhesive.
[0042] 2. The positive electrode sheet, negative electrode sheet, and separator that have completed tab die-cutting are wound in a normal order, and then processes such as flattening and welding are performed.
[0043] Among them, the conductive adhesive layer 2 is prepared from a conductive polymer material, which has a certain adhesiveness and at the same time has electrical conductivity. When the battery is flattened, the tabs 111 are bonded and fixed to each other and conduct electricity, further enabling the current collector plate to contact the tabs 111 more fully during welding, enhancing the overall electrical conductivity of the battery. At the same time, since the tabs 111 coated with the conductive adhesive layer 2 are more flexible and connectable, the probability of some tabs 111 being crushed during flattening is reduced, reducing the risk of battery short circuit and self-discharge, thus eliminating the impact on product quality and better improving the product qualification rate and safety performance; in this experiment, only the coating of the conductive adhesive layer 2 was added during coating, without increasing the complexity of the structure of the electrode sheet 100, which is simple and easy to implement.
[0044] Advantages of the present utility model:
[0045] By providing conductive adhesive layers on both the first side and the second side of the tab area of the current collector, on the one hand, the tabs can be bonded to the current collector in the tabless area at the center of the wound battery, reducing the current transmission path in the tabless area and lowering the internal resistance of the battery; on the other hand, since the tabs 111 coated with the conductive adhesive layer 2 are more flexible and connectable, the probability of some tabs 111 being crushed during flattening is reduced, reducing the risk of battery short circuit and self-discharge; at the same time, the conductive adhesive layer 2 enables the tabs 111 to be bonded and fixed to each other and conduct electricity during flattening, and can also be bonded and conduct electricity with the current collector plate, making the current collector plate contact the tabs 111 more fully during welding, enhancing the overall electrical conductivity of the battery. Overall, the safety performance and qualification rate of the product are improved.
[0046] The above is only a preferred embodiment of the present utility model and does not limit the present utility model in any form. Although the present utility model has been disclosed above with the preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications within the scope of the technical solution of the present utility model by using the disclosed technical content, which are equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present utility model, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present utility model still fall within the protection scope of the technical solution of the present utility model.
Claims
1. A pole piece, characterized in that, It includes a current collector (1), a conductive adhesive layer (2) and an active material layer (3) provided on the current collector (1); along the width direction (W) of the current collector (1), the current collector (1) includes an empty foil area (11) and an active material area (12) arranged adjacent to each other. The active material layer (3) is provided in the active material area (12). The empty foil area (11) includes a tab area (11A). The electrode sheet (100) includes opposite first surface (1A) and second surface (1B). At least part of the current collector (1) is provided with the conductive adhesive layer (2) on the first surface (1A) and the second surface (1B) of the tab area (11A).
2. The electrode sheet according to claim 1, wherein, The conductive adhesive layer (2) on the first surface (1A) of the tab area (11A) is the first conductive adhesive layer (21), and the conductive adhesive layer (2) on the second surface (1B) of the tab area (11A) is the second conductive adhesive layer (22). The thicknesses of the first conductive adhesive layer (21) and the second conductive adhesive layer (22) are the same or different.
3. The electrode sheet according to claim 2, wherein, The thickness of the first conductive adhesive layer (21) is D1, and the thickness of the active material layer (3) is D2, D1 / D2 = 1 / 7 - 1 / 30; and / or, the thickness of the second conductive adhesive layer (22) is D3, and the thickness of the active material layer (3) is D2, D3 / D2 = 1 / 5 - 1 / 30.
4. The pole piece according to claim 2, characterized in that, The thickness of the first conductive adhesive layer (21) is D1, and the thickness of the second conductive adhesive layer (22) is D3. The ranges of D1 and D3 are 0.5 - 20 μm.
5. The pole piece according to any one of claims 2-4, characterized in that, When the electrode sheet (100) is wound to form a wound battery, the second surface (1B) of the electrode sheet (100) is wound in the direction of covering the first surface (1A) of the electrode sheet (100), and the second conductive adhesive layer (22) can be bonded to the current collecting plate; the thickness of the first conductive adhesive layer (21) is D1, and the thickness of the second conductive adhesive layer (22) is D3, D3 > D1.
6. The pole piece according to claim 1, characterized in that, Along the width direction (W) of the current collector (1), the empty foil area (11) further includes a spacer area (11B). The empty foil area (11) is composed of the tab area (11A) and the spacer area (11B); the spacer area (11B) is arranged between the tab area (11A) and the active material area (12). The current collector (1) is provided with the conductive adhesive layer (2) on both the first surface (1A) and the second surface (1B) of the spacer area (11B).
7. The electrode tab according to claim 1, wherein The current collector (1) has a length direction (L). The electrode sheet (100) includes a plurality of tabs (111). Along the length direction (L) of the current collector (1), the plurality of tabs (111) are spaced apart and distributed in the tab area (11A).
8. A winding battery, characterized in that, The wound battery includes a wound battery cell, and the wound battery cell is wound after being compounded with a separator and the electrode sheet (100) according to any one of claims 1 - 7.
9. The winding battery according to claim 8, characterized in that, The wound battery further includes a current collecting plate, and the conductive adhesive layer (2) on one side can be bonded to the current collecting plate.