Tab, pole piece, electrode assembly and single battery

Abstract

The utility model provides a tab, a pole piece, an electrode assembly and a single battery. The tab comprises a body, the body is provided with a first end and a second end which are oppositely arranged, the first end is configured to be connected with a current collector of the pole piece, the body has a width size in the length direction of the pole piece in a flat state, and the width size of the second end is larger than that of the first end. The width size of the second end is set to be greater than that of the first end, so that the area of the tab can be increased on the basis of controlling the length of the connecting part between the tab and the pole piece to ensure that the tab is bent smoothly. Therefore, the current-carrying capability of the tab can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a pole ear, a pole piece, an electrode assembly and a single battery. Background Art

[0002] A single cell includes a housing, an electrode assembly disposed within the housing, and a pole disposed on the housing. Single cells are primarily categorized into cylindrical and prismatic cells based on their external shape. The electrode assembly of a cylindrical cell includes a positive electrode sheet, a separator, and a negative electrode sheet stacked and wound in sequence. The pole sheet includes a current collector and an active material layer coated on the current collector. The edge of the current collector has an empty foil area not coated with the active material layer. The empty foil area serves as a tab, electrically connecting the pole sheet to the corresponding component. The corresponding components include, but are not limited to, poles, housings, and caps.

[0003] Tabs act as current-carrying components, enabling electrical connections between the pole piece and the corresponding components. However, the current-carrying capacity of tabs still has room for improvement. Utility Model Content

[0004] The embodiments of the present application provide a tab, a pole piece, an electrode assembly, and a single battery, which can improve the current carrying capacity of the tab.

[0005] In the first aspect, an embodiment of the present application provides a pole ear, which is applied to a pole piece. The pole ear includes a body, the body having a first end and a second end arranged opposite to each other, the first end being configured to be connected to the current collector of the pole piece, and the body having a width dimension along the length direction of the pole piece in a flat state, and the width dimension of the second end is greater than the width dimension of the first end.

[0006] In one embodiment, in a direction from the first end to the second end, a width dimension of the body at least at the second end gradually increases.

[0007] In one embodiment, the width of the body gradually increases from the first end to the second end.

[0008] In one embodiment, the electrode tab has a first side, a second side and two third sides, the first side is configured to be connected to the current collector of the electrode piece, the second side is arranged opposite to the first side, and along the length direction, the two third sides are respectively located on both sides of the second side, and the two ends of the second side are respectively connected to the two ends of the first side through the two third sides; wherein, the angle between the third side and the first side is 90°<α≤135°.

[0009] In one embodiment, the second end has a second side away from the first end, and the second side is convex in a direction away from the first end to form an arc structure.

[0010] In an embodiment, the first end has a first side configured to be connected with the current collector of the pole piece, along the width direction of the pole piece, the distance between the end of the second side and the straight line where the first side is located is H1, and the distance between the highest point of the outward protrusion of the second side and the straight line where the first side is located is H2, satisfying: H1

[0011] In an embodiment, an insulating layer is arranged on the body, and the insulating layer is arranged adjacent to the first end.

[0012] In a second aspect, an embodiment of the present application provides a pole piece, which comprises a current collector, an active material layer, and the tab as described above; the current collector has a long side and a wide side; the active material layer is arranged on the current collector; and the first end is connected with the long side of the current collector.

[0013] In a third aspect, an embodiment of the present application provides an electrode assembly, which comprises a positive pole piece, a separator, and a negative pole piece arranged in sequence and wound, wherein at least one of the positive pole piece and the negative pole piece is the pole piece as described above.

[0014] In a fourth aspect, an embodiment of the present application provides a single battery, which comprises a shell, a cap assembly, and the electrode assembly as described above, the shell has a receiving cavity; the cap assembly is combined with the shell to close the receiving cavity; and the electrode assembly is arranged in the receiving cavity.

[0015] The beneficial effects of the embodiments of the present application are as follows:

[0016] In the embodiments of the present application, by setting the width dimension of the second end to be greater than the width dimension of the first end, the length of the connecting part between the tab and the pole piece can be controlled, so as to ensure the smooth bending of the tab, and the area of the tab can be increased. In this way, the current carrying capacity of the tab can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0018] Figure 1 is a first structure schematic diagram of the tab provided by an embodiment of the present application;

[0019] Figure 2 is a second structure schematic diagram of the tab provided by an embodiment of the present application;

[0020] Figure 3 is a third structure schematic diagram of the tab provided by an embodiment of the present application;

[0021] Figure 4 This is a schematic diagram of the fourth structure of the tab provided in the embodiment of the present application;

[0022] Figure 5 This is a fifth structural diagram of the tab provided in the embodiment of the present application.

[0023] Figure 6 Schematic diagram of the structure of the pole piece provided in the embodiment of the present application;

[0024] Figure 7 is a top view of an electrode assembly provided in an embodiment of the present application;

[0025] Figure 8 It is a schematic structural diagram of a single cell provided in an embodiment of the present application.

[0026] Description of reference numerals:

[0027] 1-Pole ear;

[0028] 11-first side; 12-second side; 13-third side; 14-insulating layer; 15-body; 16-first end; 17-second end;

[0029] 2-pole piece; 21-current collector; 22-active material layer;

[0030] 3-electrode assembly; 31-positive electrode plate; 32-diaphragm; 33-negative electrode plate;

[0031] 4- single cell; 41- housing; 42- cap assembly. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0033] In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not intended to limit the present application. In the present application, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0035] The terms "comprises," "comprising," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a product that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such product.

[0036] In the description of the embodiments of this application, words such as "example" or "for example" are used to indicate an example, illustration, or description. Any embodiment or design described as "for example" or "for example" in the embodiments of this application is not to be construed as being preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to clearly present relative concepts.

[0037] To facilitate understanding of the solution of the present application, before introducing the tab, electrode sheet, electrode assembly and single cell provided by the present application, the relevant technologies of the present application are first described.

[0038] In the related art, cylindrical single cells are mainly categorized as aluminum-cased and steel-cased. Steel-cased single cells consist of a steel casing, a wound electrode assembly housed within the casing, and a cap assembly. The cap assembly is installed at the opening of the steel casing. A groove is formed on the steel casing near the cap assembly through a rolling process, and a buckle edge is formed at the end of the steel casing, allowing the steel casing to securely fasten the cap assembly. In some steel-cased single cells, the positive electrode tab is welded to the cap, forming one output terminal, while the negative electrode tab is connected to the steel casing, forming the other output terminal. To control the height of the tab, it is necessary to bend it. Therefore, the connection between the tab and the electrode sheet should not be too large to prevent it from bulging outward when the tab is bent. This results in a smaller tab size, which limits the current-carrying capacity of the tab. Furthermore, the smaller tab size reduces the weld surface area between the tab and the corresponding component, resulting in poor weld reliability.

[0039] Based on this, the embodiments of the present application provide a tab, a pole piece, an electrode assembly and a single cell, which can increase the area of ​​the tab without affecting the bending of the tab to improve the current carrying capacity of the tab, thereby improving the flow capacity between the pole piece and the corresponding component.

[0040] See also Figure 1 or Figure 2 , Figure 1 This is a schematic diagram of the first structure of the tab 1 provided in an embodiment of the present application. Figure 2 This is a schematic diagram of a second structure of a tab 1 provided in an embodiment of the present application. This embodiment of the present application provides a tab 1 for use with a pole piece. The tab 1 includes a body 15 having a first end 16 and a second end 17 disposed opposite each other. The first end 16 is configured to connect to the current collector of the pole piece. The body 15 has a width dimension along the length of the pole piece when it is flat. The width dimension W of the first end 16 is greater than the width dimension W of the second end 17.

[0041] It can be understood that the end of the tab 1 away from the pole piece is used for welding with the corresponding component.

[0042] The second end 17 may be convexly arranged along the length direction of the electrode, so that the width dimension W of the second end 17 is greater than the width dimension W of the first end 16, as shown in FIG. Figure 1 or Figure 2 It can also be from the first end 16 to the second end 17, the width dimension W of the body 15 gradually increases, so that the width dimension W of the second end 17 is greater than the width dimension W of the first end 16, as Figure 3 shown.

[0043] In this embodiment, by setting the width W of the second end 17 to be greater than the width W of the end 16, the length of the connection portion between the tab 1 and the electrode sheet 2 can be controlled to ensure smooth bending of the tab 1 while increasing the area of ​​the tab 1. This not only improves the current carrying capacity of the tab 1, but also allows for a longer welding track to be arranged on the tab 1, thereby increasing the welding area between the tab 1 and the corresponding component, thereby improving the welding reliability between the tab 1 and the corresponding component.

[0044] See also Figure 2 In one embodiment, the width W of the body 15 gradually increases from the first end 16 toward the second end 17, at least at the second end 17. This reduces the number of inflection points along the edge of the tab 1, thereby reducing stress concentration and improving the uniformity of force applied to the tab 1. Furthermore, this configuration simplifies the control steps for cutting the tab 1, thereby improving the efficiency of cutting the tab 1.

[0045] See also Figure 3In an embodiment, the width dimension W of the body 15 gradually increases from the first end 16 to the second end 17. In this way, the number of inflection points on the edge of the tab 1 can be further reduced, thereby reducing stress concentration and improving the uniformity of stress on the tab 1. In addition, this arrangement can further simplify the control step of cutting the tab 1 and improve the cutting efficiency of the tab 1.

[0046] Referring to Figure 3 In an embodiment, the tab 1 has a first edge 11, a second edge 12, and two third edges 13. The first edge 11 is configured to be connected to the current collector of the tab sheet. The second edge 12 is arranged opposite to the first edge 11. The two third edges 13 are respectively located on the two sides of the second edge 12 in the length direction. The two ends of the second edge 12 are respectively connected to the two ends of the first edge 11 through the two third edges 13. The included angle between the third edge 13 and the first edge 11 is 90° < a ≤ 135°.

[0047] It can be understood that the included angle a between the third edge 13 and the first edge 11 includes but is not limited to 91°, 95°, 98°, 100°, 105°, 109°, 112°, 115°, 118°, 120°, 122°, 125°, 128°, 130°, 133°, and 135°.

[0048] Specifically, the included angle a between the two third edges 13 and the first edge 11 is equal, so that the structure of the tab 1 is symmetrical, which can improve the stress state and reduce the difficulty of cutting and forming the tab 1.

[0049] In this embodiment, by limiting the range of the included angle a between the third edge 13 and the first edge 11, on the one hand, the width dimension of the second end 17 can be ensured to be greater than that of the first end 16; on the other hand, the width dimension of the second end 17 can be prevented from being too wide due to the too large angle, thereby ensuring the reliability of the single battery 4 using the tab 1.

[0050] Referring to Figure 4 , Figure 4 is a fourth structure diagram of the tab 1 provided by the embodiments of the present application. In an embodiment, the second end 17 has a second edge 12 away from the first end 16. The second edge 12 is outwardly convex as a circular arc structure away from the first end 16. In this way, the included angle of the cutting side of the tab 1 can be further increased to effectively avoid damage to the corner of the tab 1 or scratch other components.

[0051] It can be understood that the width dimension W of the tab 1 is the distance between the two third edges 13 connected between the first edge 11 and the second edge 12.

[0052] Referring to Figure 4In one embodiment, the first end 16 has a first edge 11 configured to connect to the current collector of the electrode. Along the width direction of the electrode 2, the distance between the end of the second edge 12 and the line along which the first edge 11 lies is H1, and the distance between the highest point of the convex portion of the second edge 12 and the line along which the first edge 11 lies is H2, satisfying the following relationship: H1

[0053] It will be understood that H2 includes but is not limited to 1.02H1, 1.03H1, 1.04H1, 1.05H1, 1.06H1, 1.09H1, 1.2H1, 1.22H1, 1.25H1, 1.26H1, 1.28H1, and 1.3H1.

[0054] For example, when H1 is 6 mm, the value range of H2 is 6 mm

[0055] In this embodiment, through the above-mentioned limitation, on the one hand, the tab 1 can have a larger area through the protruding second side 12, so as to improve the current-carrying capacity of the tab 1 and facilitate welding; on the other hand, the protrusion degree of the second side 12 can be controlled to control the overall height of the tab 1, thereby avoiding the tab 1 from contacting other components and causing a short circuit.

[0056] See also Figure 5 , Figure 5 This is a fifth structural diagram of the tab 1 provided in an embodiment of the present application. In one embodiment, an insulating layer 14 is provided on the body 15 , and the insulating layer 14 is provided adjacent to the first end 16 .

[0057] Specifically, the insulating layer 14 is provided on at least one side of the convex surface formed after the tab 1 is bent.

[0058] Among them, the insulating layer 14 can be optionally an insulating tape or insulating paper, for example, insulating paper with acrylic adhesive and polyimide as the base material, which has good high temperature resistance, needle puncture resistance, tensile strength, electrolyte corrosion resistance and electrical insulation.

[0059] It can be understood that after the tab 1 is bent, both sides of its root portion tend to extend beyond the circumference of the portion on the electrode sheet where it is connected, thereby causing the root portion of the tab 1 to be closer to the outer shell of the single battery.

[0060] Based on this, in this embodiment, by providing an insulating layer 14 at the root of the tab 1 , the insulation between the root of the tab 1 and other components not electrically connected thereto can be improved, thereby improving the reliability of the single battery using the tab 1 .

[0061] The above embodiments are summarized to obtain the following contents.

[0062] See also Figure 5 ​​Please refer to the figure. In some embodiments, the tab 1 is applied to the pole piece 2. The tab 1 includes a body 15, and the body 15 has a first end 16 and a second end 17 arranged opposite to each other. The first end 16 has a first edge 11, and the second end 17 has a second edge 12 away from the first end. The first edge 11 is configured to be connected to the current collector 21 of the pole piece 2. Along the length direction of the pole piece 2 in a flat state, the body 15 has a width dimension W. The width dimension W of the second end 17 is greater than the width dimension W of the first end 16. The width dimension W of the body 15 gradually increases in the direction away from the pole piece 2. The body 15 also has two third edges 13. Along the length direction, the two third edges 13 are respectively located on both sides of the second edge 12. The two ends of the second edge 12 are connected to the two ends of the first edge 11 through the two third edges 13. The angle between the third edge 13 and the first edge 11 is 90°<α≤135°. The second edge 12 bulges outward in a circular arc structure in the direction away from the pole piece 2. Along the width of the electrode 2, the distance between the end of the second side 12 and the line along which the first side 11 lies is H1, and the distance between the highest point of the outward projection of the second side 12 and the line along which the first side 11 lies is H2, satisfying the following: H1 < H2 ≤ 1.3H1. An insulating layer 14 is disposed on the body 15, adjacent to the first side 11.

[0063] See also Figure 6 , Figure 6 Schematic diagram of the structure of a pole piece 2 provided in an embodiment of the present application. Accordingly, an embodiment of the present application provides a pole piece 2. The pole piece 2 includes a current collector 21, an active material layer 22, and a tab 1 provided in some embodiments of the present application. The current collector 21 has a long side and a wide side. The active material layer 22 is disposed on the current collector 21. The first end 16 is connected to the long side of the current collector 21.

[0064] It is understandable that the tab 1 and the current collector 21 may be welded, or the tab 1 and the current collector 21 may be integrally formed.

[0065] The active material layer 22 of the positive electrode plate 31 may include lithium iron phosphate (LiFePO 4 ), lithium nickel manganese cobalt oxide (LiNiMnCoO 2 ), lithium cobalt oxide (LiCoO 2 ), lithium nickel cobalt aluminum oxide (LiNiCoAlO 2 ), and the like.

[0066] The active material layer 22 of the negative electrode sheet 33 may include graphite, silicon, tin, etc.

[0067] Optionally, the pole piece 2 has one or two pole lugs 1 .

[0068] In this embodiment, by adopting the tab 1 provided in some embodiments of the present application, the length of the connection portion between the tab 1 and the pole piece 2 can be controlled to ensure smooth bending of the tab 1, while increasing the area of ​​the tab 1. In this way, the current carrying capacity of the tab 1 can be improved, thereby improving the current carrying capacity of the pole piece 2, and a longer welding track can be arranged on the tab 1 to increase the welding area between the tab 1 and the corresponding component, thereby improving the welding reliability between the tab 1 and the corresponding component, thereby ensuring the welding reliability between the pole piece 2 and the corresponding component.

[0069] See also Figure 7 , Figure 7 FIG2 is a top view of an electrode assembly 3 provided in an embodiment of the present application. Accordingly, an embodiment of the present application provides an electrode assembly 3. The electrode assembly 3 includes a positive electrode sheet 31, a separator 32, and a negative electrode sheet 33, which are sequentially stacked and wound. At least one of the positive electrode sheet 31 and the negative electrode sheet 33 is the aforementioned electrode sheet 2.

[0070] Illustratively, the positive electrode plate 31 is the aforementioned electrode plate 2 , or the negative electrode plate 33 is the aforementioned electrode plate 2 , or both the positive electrode plate 31 and the negative electrode plate 33 are the aforementioned electrode plate 2 .

[0071] In this embodiment, by adopting the electrode piece 2 provided in some embodiments of the present application, the current carrying capacity of the electrode assembly 3 can be improved, and a longer welding track can be arranged on the electrode tab 1 to increase the welding area between the electrode tab 1 and the corresponding component, thereby improving the welding reliability between the electrode tab 1 and the corresponding component to ensure the welding reliability between the electrode assembly 3 and the corresponding component.

[0072] See also Figure 8 , Figure 8 Figure 4 is a schematic diagram of the structure of a single cell 4 provided in an embodiment of the present application. This embodiment of the present application provides a single cell 4. The single cell 4 includes a housing 41, a cap assembly 42, and an electrode assembly 3 provided in some embodiments of the present application. The housing 41 has a receiving cavity; the cap assembly 42 fits over the housing 41 to seal the receiving cavity. The electrode assembly 3 is disposed in the receiving cavity.

[0073] In this embodiment, by adopting the electrode assembly 3 provided in some embodiments of the present application, the current carrying capacity of the single cell 4 can be improved, and a longer welding track can be arranged on the pole tab 1 to increase the welding area between the pole tab 1 and the corresponding component, thereby improving the welding reliability between the pole tab 1 and the corresponding component, ensuring the welding reliability between the electrode assembly 3 and the corresponding component, and further improving the structural reliability of the single cell 4.

[0074] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A tab, applied to a pole piece, characterized in that: The electrode tab includes a body having a first end and a second end arranged opposite to each other, the first end being configured to be connected to the current collector of the electrode piece, and the body having a width dimension along the length direction of the electrode piece in a flat state, and the width dimension of the second end is greater than the width dimension of the first end.

2. The tab according to claim 1, wherein: In a direction from the first end to the second end, a width dimension of the body at least at the second end gradually increases.

3. The tab according to claim 2, wherein: The width of the body gradually increases from the first end to the second end.

4. The tab according to claim 3, wherein: The electrode tab has a first side, a second side, and two third sides, wherein the first side is configured to be connected to the current collector of the electrode sheet, the second side is arranged opposite to the first side, and along the length direction, the two third sides are respectively located on both sides of the second side, and the two ends of the second side are respectively connected to the two ends of the first side through the two third sides; The included angle between the third side and the first side is 90°<α≤135°.

5. The tab according to any one of claims 1 to 3, characterized in that: The second end has a second side away from the first end, and the second side is convex in a direction away from the first end to form an arc structure.

6. The tab according to claim 5, characterized in that: The first end has a first edge configured to be connected to the current collector of the pole piece. Along the width direction of the pole piece, the distance between the end of the second edge and the straight line where the first edge is located is H1, and the distance between the highest point of the bulge of the second edge and the straight line where the first edge is located is H2, satisfying: H1<H2≤1.3H1.

7. The tab according to any one of claims 1 to 4, characterized in that: An insulating layer is provided on the body, and the insulating layer is provided adjacent to the first end.

8. A pole piece, characterized in that: include: a current collector having a long side and a wide side; an active material layer, disposed on the current collector; And, in at least one electrode tab according to any one of claims 1 to 7, the first end is connected to a long side of the current collector.

9. An electrode assembly, characterized in that: It comprises a positive electrode sheet, a separator and a negative electrode sheet stacked and wound in sequence, wherein at least one of the positive electrode sheet and the negative electrode sheet is the electrode sheet according to claim 8.

10. A single cell battery, characterized in that: include: A housing having a receiving cavity; a cap assembly, covering the shell to close the accommodating cavity; And, the electrode assembly as claimed in claim 9 is disposed in the accommodating cavity.

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