Tab structure and pole piece welded with same

Abstract

The utility model belongs to the technical field of batteries, and mainly relates to a tab structure, a body of the tab structure is provided with a welding area, and the welding area is provided with at least two grooves; wherein the welding area comprises a first welding area and a second welding area, the number of transversely arranged grooves in the first welding area is smaller than that of transversely arranged grooves in the second welding area, and a blank area is arranged between the first welding area and the second welding area; through the design, a plurality of blank areas exist in the welding area, so that the inherent limitation of single-point welding in the aspect of strength is successfully made up, the connection firmness between the tab and the pole piece is also greatly improved, and the risk that the tab falls off when the battery cell is collided is greatly reduced; meanwhile, the utility model further designs a pole piece of the tab structure, so that the strength of single-point welding is further improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the battery technical field, concretely relates to a tab structure and the tab piece welded with it. BACKGROUND

[0002] In recent years, with the rapid development of battery technology, the demand for battery performance is constantly improving, among which the volume energy density (ED) and welding strength of the battery are the key indicators. The welding strength of the tab and the tab piece has a crucial influence on the battery performance. It not only directly relates to the mechanical stability of the battery, but also affects the electrochemical performance and long service life of the battery.

[0003] The traditional three-point welding process has been applied for a period of time. Although it can provide strong welding tension and stability, the length of the welding area is large, which limits the effective utilization area of the tab, thereby restricting the improvement of the volume energy density of the battery. Therefore, the prior art introduces a single-point welding process to reduce the length of the welding area and increase the effective utilization area of the tab, thereby improving the ED advantage. However, through the experiment of the present application, it is found that although the single-point welding optimizes the space utilization, it inevitably leads to a decrease in the tensile strength of the welding point. This decrease increases the risk of tab falling off when the battery is collided or impacted, thereby challenging the safety and reliability of the battery.

[0004] Therefore, it is urgent to improve the existing single-point welded tab structure and tab to solve the defects of the prior art. SUMMARY

[0005] One of the purposes of the utility model is to provide a tab structure that can balance the welding space utilization and welding strength during single-point welding in view of the deficiencies of the prior art.

[0006] In order to achieve the above technical purpose, the present application implements the following technical scheme:

[0007] A tab structure, the body of the tab structure is provided with a welding area, and the welding area is provided with at least two grooves; the welding area includes a first welding area and a second welding area, the number of grooves arranged transversely in the first welding area is less than the number of grooves arranged transversely in the second welding area; a blank area is provided between the first welding area and the second welding area.

[0008] Through the above technical scheme, the present application achieves the following technical effects:

[0009] The application is provided with multiple blank areas in the welding area of the welding mark (especially the groove structure in the design), so that the external stress borne by the welding mark during the welding process is effectively dispersed, thereby significantly enhancing the tensile performance of the welding while expanding the effective welding area of the single-point welding mark. The above technical solution not only successfully makes up for the inherent limitation of the single-point welding in terms of strength, but also greatly improves the connection firmness between the tab and the pole piece, thereby greatly reducing the risk of tab falling off when the battery cell encounters a collision.

[0010] As a further improvement of the tab structure of the utility model, when the grooves are transversely arranged with adjacent grooves, the transverse groove distance of the grooves and the adjacent grooves along the width direction of the welding area is W1; when the grooves are longitudinally arranged with adjacent grooves, the longitudinal groove distance of the grooves and the adjacent grooves along the length direction of the welding area is W2; wherein the range of W1 is: 0.5mm-1.5mm, and the range of W2 is: 0.2mm-2mm.

[0011] As a further improvement of the tab structure of the utility model, when the grooves are transversely arranged with adjacent grooves, the transverse groove distance of the grooves and the adjacent grooves along the width direction of the welding area is W1; when the grooves are longitudinally arranged with adjacent grooves, the longitudinal groove distance of the grooves and the adjacent grooves along the length direction of the welding area is W2; wherein the range of W1 is: 0.5mm-1.5mm, and the range of W2 is: 0.2mm-2mm.

[0012] As a further improvement of the tab structure of the utility model, the first welding area and the second welding area are arranged at intervals, the number of the first welding area is at least one, and the number of the second welding area is at least one.

[0013] As a further improvement of the tab structure of the utility model, the thickness value of the body is H1, and the depth value of the groove is H2, wherein the value range of H1 is 0.05mm-0.1mm, and the value range of H2 is 0.05mm-0.1mm.

[0014] As a further improvement of the tab structure of the utility model, the width value of the groove is D1, and the value range of D1 is 0.5mm-0.6mm.

[0015] As a further improvement of the tab structure of the utility model, the width of the groove is greater along the thickness direction of the body as it is farther away from the welding surface of the body.

[0016] As a further improvement of the tab structure of the utility model, the length of the welding area is L1, and the range of L1 is: 8mm-10mm; the width of the welding area is L2, and the range of L2 is: 3mm-4mm.

[0017] As a further improvement of the tab structure of the utility model, the groove surface is rhombic.

[0018] The second purpose of the utility model is to provide a tab piece which can consider welding strength and battery capacity in a single-point welding process in view of the deficiency of the prior art.

[0019] In order to achieve the above technical purpose, the following technical scheme is implemented in the application:

[0020] A tab piece welded with the tab structure of any one of the above, comprising a current collector, the surface of the current collector being divided into a coated area and a to-be-welded area; the coated area is coated with positive electrode paste or negative electrode paste; the to-be-welded area is used for welding with the welding area of the tab structure of any one of the above through a welding device.

[0021] The above technical scheme produces the following technical effects:

[0022] Through the above technical scheme, the application achieves the following technical effects:

[0023] The tab piece design of the utility model sets a coated area and a to-be-welded area on the surface of the current collector, so that the tab piece can effectively improve the capacity of the battery while maintaining the welding strength. The positive or negative electrode paste coated in the coated area can provide the necessary electrochemical activity, and the to-be-welded area ensures the welding strength with the tab structure. In particular, the hollow foil area set in the to-be-welded area corresponds to the groove of the tab structure, further optimizing the stress distribution of the welding point, enhancing the reliability of welding, and at the same time reducing the occupation of the welding area to the battery capacity, thereby improving the energy density of the battery without sacrificing the performance of the battery.

[0024] As a further improvement of the utility model tab piece, the to-be-welded area is provided with a hollow foil area, the position of the hollow foil area corresponds to the groove of the tab structure of any one of the above, and the to-be-welded area is coated with paste outside the hollow foil area. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the utility model, constitute a part of the utility model, the schematic embodiments of the utility model and the explanations thereof are used to explain the utility model, and do not constitute an improper limitation on the utility model. In the drawings:

[0026] Figure 1 It is a top view of the tab structure in the utility model;

[0027] Figure 2 It is Figure 1 It is a sectional view along the width direction of the groove;

[0028] Figure 3 It is a structural schematic view of the tab piece in the utility model;

[0029] Among them:

[0030] 100-tab structure;

[0031] 1-body;

[0032] 11-welding zone;

[0033] 12-groove;

[0034] 13-first welding area;

[0035] 14-second welding area;

[0036] 15-welding surface;

[0037] 16-blank area;

[0038] 2-current collector;

[0039] 21-coating area;

[0040] 22-welding area;

[0041] 221-foil-free area. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. Unless otherwise defined, all the technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application.

[0043] In the description of the present application, unless otherwise explicitly defined and limited, the terms "mounting", "connection", "connecting", "fixing" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0044] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the claims, and any person skilled in the art can make several possible changes and modifications without departing from the concept of the present application, therefore the protection scope of the present application should be limited by the scope defined by the claims of the present application.

[0045] The utility model is further described in detail below in combination with specific embodiments, but the embodiments of the utility model are not limited thereto.

[0046] It is known that, in the cell row welding process, although the single-point welding method exhibits significant advantages in expanding the area of the effective welding area 11 compared to the three-point welding mode, thereby achieving the reduction of the design requirements for the length of the tab structure 100 welding area 11. However, in practical application, this welding method requires only a small gap (tending to be no gap, which can be basically ignored by the person skilled in the art in operation) or no gap between the welding marks on the tab welding area 11, which leads to the phenomenon that the tab welding marks are easily connected to each other or exceed the predetermined welding area 11 boundary during the welding process.

[0047] Specifically, through in-depth experiments, the present application found that too small welding mark size between tabs can lead to unstable welding conditions between welding marks, which is specifically manifested as follows: under the action of external force, the stress of a single welding mark will affect the adjacent welding mark, and due to uneven stress between the welding marks, combined with the narrow gap between the welding marks and the welding marks, irregular solder is often generated, thereby weakening the ability of the tabs connected by such welding marks to withstand strong tension, and ultimately possibly leading to failure of the battery tab equipped with such welding tabs due to external force in actual work. Accordingly, the present application generates an invention motivation for improving the battery tensile capacity by regulating the horizontal and vertical gaps between the welding marks on the tab welding area 11, which can enable the tab to simultaneously maintain the low welding length of the tab brought by single-point welding and the high tensile performance achieved by the present application when the tab is welded with the current collector 2 air foil area 221.

[0048] Further, as shown in Figure 1 , the present application provides a tab structure 100, the body 1 of the tab structure 100 is provided with a welding area 11, and the welding area 11 is provided with at least two grooves 12 (which are specific manifestation structures of the welding marks on the tab structure 100). The welding area 11 includes a first welding area 13 and a second welding area 14, and the number of the grooves 12 arranged transversely in the first welding area 13 is less than the number of the grooves 12 arranged transversely in the second welding area 14. Wherein, the present application does not limit the number of the grooves 12 arranged longitudinally in the first welding area 13 and the second welding area 14, and in the specific implementation process, the number of the grooves 12 arranged longitudinally in the first welding area 13 and the second welding area 14 can be preferably any one of 1, 2, 3. In Figure 1 , the first welding area 13 and the first welding area 13 are continuously arranged, at this time a blank area 16 which can disperse the stress of the grooves 12 is formed, thereby improving the tensile force of the welding area 11 after welding.

[0049] Further, the first welding area 13 and the second welding area 14 are arranged in intervals, the number of the first welding area 13 is at least one, and the number of the second welding area 14 is at least one. In the specific implementation process, since the number of the first welding area 13 transversely arranged grooves 12 is less than the number of the second welding area 14 transversely arranged grooves 12, it results in that a part of the grooves 12 in the second welding area 14 are longitudinally arranged with the grooves 12 in the adjacent first welding area 13, and can only be longitudinally arranged with the grooves 12 in the other second welding area 14 which is spaced apart. And this design of the tab structure 100 grooves 12 makes the tab most susceptible to external force. The place can be designed with more blank areas 16 to improve the ability to disperse external force.

[0050] When the grooves 12 are transversely arranged with the adjacent grooves 12, the transverse groove distance of the grooves 12 and the adjacent grooves 12 along the width direction (X direction) of the welding area 11 is W1; when the grooves 12 are longitudinally arranged with the adjacent grooves 12, the longitudinal groove distance of the grooves 12 and the adjacent grooves 12 along the length direction (Y direction) of the welding area 11 is W2; wherein, the range of W1 is: 0.5mm-1.5mm, and the range of W2 is: 0.2mm-2mm. In the specific implementation process, W1 can be preferably any one of: 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm. W2 can be preferably any one of: 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm and 2.0mm.

[0051] Further, as shown in FIG. 1, the tab structure 100 is provided with a plurality of grooves 12, and the plurality of grooves 12 are arranged in intervals. The plurality of grooves 12 are arranged in intervals in the length direction (Y direction) of the welding area 11, and the plurality of grooves 12 are arranged in intervals in the width direction (X direction) of the welding area 11. The plurality of grooves 12 are arranged in intervals in the length direction (Y direction) of the welding area 11, and the plurality of grooves 12 are arranged in intervals in the width direction (X direction) of the welding area 11. The plurality of grooves 12 are arranged in intervals in the length direction (Y direction) of the welding area 11, and the plurality of grooves 12 are arranged in intervals in the width direction (X direction) of the welding area 11. Figure 1As shown: the welding area 11 includes a first welding area 13 and a second welding area 14, the number of grooves 12 arranged transversely in the first welding area 13 is less than the number of grooves 12 arranged transversely in the second welding area 14. Wherein, the application does not limit the number of grooves 12 arranged longitudinally in the first welding area 13 and the second welding area 14, and in the specific implementation process, the number of grooves 12 arranged longitudinally in the first welding area 13 and the second welding area 14 can be preferably any one of 1, 2, 3. It should be noted that the first welding area 13 and the second welding area 14 are arranged at intervals, the number of the first welding area 13 is at least one, and the number of the second welding area 14 is at least one. In the specific implementation process, since the number of grooves 12 arranged transversely in the first welding area 13 is less than the number of grooves 12 arranged transversely in the second welding area 14, it leads to that a part of the grooves 12 in the second welding area 14 and the grooves 12 in the adjacent first welding area 13 exist longitudinal arrangement, and only the grooves 12 in the second welding area 14 arranged at intervals can be longitudinally arranged. And this design of the groove 12 of the tab structure 100 makes the place where the tab is most easily affected by external force can be designed to have more space area, thereby improving the ability to disperse external force.

[0052] Further, as shown: Figure 2 The thickness of the body 1 in the application is H1, and the depth of the groove 12 is H2, wherein the value range of H1 is 0.05mm-0.1mm, and the value range of H2 is 0.05mm-0.1mm. Specifically, H1 can be preferably: 0.05m, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm; H2 can be preferably: 0.05m, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm; It should be noted that there are two cases of the depth of the groove 12 in the application, one is that the depth of the groove 12 is consistent with the thickness of the body 1, that is, the groove 12 will penetrate the body 1 in the thickness direction (Z direction) of the body 1, and through such design, a welding point can be formed on the other side of the tab during the process of welding the tab and the tab by the welding head through the groove 12, thereby realizing the effect of double-sided welding; The second is that the depth of the groove 12 is less than the thickness of the body 1, that is, the groove 12 does not penetrate the body 1, which can increase the contact area between the tab and the tab and improve the stability and strength of the welding. In actual application, the appropriate depth of the groove 12 can be selected according to the use requirements of the battery tab and the performance of the welding equipment.

[0053] Further, the width of the groove 12 is D1, and the range of D1 is 0.5mm-0.6mm. In the specific implementation process, the width of the groove 12 along the thickness direction of the body 1 is larger as it is farther away from the welding surface 15 of the body 1. This design is to consider that the area of the welding head in contact with the pole piece gradually increases during welding, so that the welding is more stable and uniform, and at the same time, it can effectively avoid the phenomenon of over-heating or burning of the welding point due to local heat concentration during welding, and also helps to improve the welding efficiency and welding quality.

[0054] Further, the length of the welding area 11 is L1, and the range of L1 is 8mm-10mm; the width of the welding area 11 is L2, and the range of L2 is 3mm-4mm. In the specific implementation process, L1 can be preferably any one of 8.0mm, 8.1mm, 8.2mm, 8.3mm, 8.4mm, 8.5mm, 8.6mm, 8.7mm, 8.8mm, 8.9mm, 9.0mm, 9.1mm, 9.2mm, 9.3mm, 9.4mm, 9.5mm, 9.6mm, 9.7mm, 9.8mm, 9.9mm, 10.0mm. L2 can be preferably any one of 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm. Through such design, it can ensure that the size of the welding area 11 meets the welding requirements of the battery pole piece, and at the same time, it can ensure the stability of the welding process and the welding quality.

[0055] Further, the groove 12 has a rhombus-shaped groove surface, which is a standard welding shape in welding, and the width of the groove 12 in this application is specifically the length of the rhombus side, Figure 2 is a cross-sectional view of the tab structure 11 along the length direction of the groove 12.

[0056] Further, as Figure 3 shown: the application also designs a pole piece welded with any one of the above tab structures 100, which includes a current collector 2, wherein the surface of the current collector 2 is divided into a coated area 21 and a to-be-welded area 22; the coated area 21 is coated with positive or negative slurry; the to-be-welded area 22 is used for welding with the welding area 11 of any one of the above tab structures 100 through a welding device. The to-be-welded area 22 is provided with a hollow foil area 221, and the hollow foil area 221 is located corresponding to the groove 12 of any one of the above tab structures 100, and the to-be-welded area 22 is coated with slurry outside the hollow foil area 221. Through the above design, the groove 12 of the application corresponds one-to-one with the hollow foil area 221 in the to-be-welded area 22 of the pole piece, and the non-hollow foil area 221 in the to-be-welded area 22 is coated with slurry, which further improves the battery capacity of the pole piece of the application.

[0057] To more clearly demonstrate the technical effects brought by the improvements of the tab structure 100, the application designs the preferred tab structure 100 design schemes as shown in Examples 1-5 and compares them with the existing tab structure 100 design schemes shown in Comparative Examples 1-3. Specifically, the application fixes the tab structures 100 in Examples 1-5 and the existing tab structures 100 in Comparative Examples 1-3 on the pole piece by single-point welding, and then prepares the battery cell. Subsequently, the battery cell is subjected to multiple welding tension tests to comprehensively evaluate its performance.

[0058] Further, all tests are carried out in accordance with national standards (such as GB / T 24344-2009), and the specific test method is as follows:

[0059] The standard tensile test method is used to test the welding tab. During the test, the welding point is gradually stretched within a standard time interval until the tab and the pole piece are separated, and the welding tension value is recorded.

[0060] Further, the test device uses an automatic tensile testing machine equipped with a high-precision force sensor and a data recording system to ensure the accuracy and repeatability of the data.

[0061] Test result statistics: for the welding tension test results of Examples 1-5 and Comparative Examples 1-3, the following statistical data are recorded:

[0062] Mean: represents the overall level of the tensile test results.

[0063] Minimum value: reflects the lowest level of tab welding strength.

[0064] Maximum value: shows the highest level of welding strength.

[0065] Median value: provides the median value of the welding tension distribution, showing the central tendency of the data.

[0066] Sigma (standard deviation): represents the dispersion degree of the welding tension results, reflecting the consistency and reliability of the welding strength.

[0067] Example 1

[0068] The body 1 of the tab structure 100 has a width of 6 mm and a thickness of 0.08 mm, and the material of the body 1 is a nickel tab. The welding area 11 has a length of 10 mm and a width of 4 mm, the groove 12 has a width of 0.6 mm, the transverse distance between adjacent grooves 12 is 1 mm, and the longitudinal distance is 0.5 mm.

[0069] Example 2

[0070] Unlike Example 1, in this example, the width of the welding zone 11 is 3 mm.

[0071] Example 3

[0072] Unlike Example 1, the longitudinal spacing between adjacent grooves 12 is at most 0.2 mm.

[0073] Example 4

[0074] Unlike Example 1, the longitudinal spacing between adjacent grooves 12 is at most 1.0 mm.

[0075] Example 5

[0076] Unlike Example 1, the lateral spacing between adjacent grooves 12 is 0.5 mm.

[0077] Example 6

[0078] Unlike Example 1, the lateral spacing between adjacent grooves 12 is 1.5 mm.

[0079] Comparative Example 1

[0080] Unlike Example 1, there is no lateral and longitudinal spacing between adjacent grooves 12.

[0081] The experimental welding tensile force data of the battery cells prepared in Examples 1-6 and Comparative Example 1 above are as follows:

[0082]

[0083] Table 1

[0084] From the above experimental data, by comparing the data of Example 1 and Comparative Example 1, it can be analyzed that by adjusting the structure of the tab 100 (designing the lateral and longitudinal spacing between adjacent grooves 12) in the present application, the length of the welding zone 11 is reduced, the effective utilization area of the tab is increased, thereby improving the volumetric energy density (ED) of the battery cell, and solving the technical defect of small post-welding tensile force of the existing single-point welding tab structure as in Comparative Example 1.

[0085] As can be seen from the comparison between Example 1 and Example 2, increasing the width of the groove 12 (weld mark) can effectively increase the pulling force of the welding machine. As can be seen from the comparison between Example 1, Example 3 and Example 4, the optimal value of the longitudinal spacing between adjacent grooves 12 is 0.5 mm. When the longitudinal spacing is too small, the area of the blank area 16 is too small, and the pulling force is insufficient. When the longitudinal spacing is too large, the area of the blank area 16 is too large, and the actual weld mark area is too small, resulting in a decrease in the pulling force. It should be noted that in the description of Example 4, the maximum longitudinal spacing of the groove 12 refers to the specific spacing when at least one first welding area 13 is intermittently placed between two second welding areas 14. This spacing is formed because the groove 12 of the second welding area 14 does not directly correspond to the first welding area 13, but only corresponds to the groove 12 of another second welding area 14, thereby forming the maximum spacing distance in the longitudinal direction. At the same time, this spacing also produces the blank area 16 that can increase the pulling force of the welding area after welding as mentioned in this application.

[0086] Further, as can be seen from the comparison between Example 1, Example 5 and Example 6, the optimal value of the lateral spacing between adjacent grooves 12 is 1 mm. When the lateral spacing between adjacent grooves 12 is too small, the area of the blank area 16 is too small, and the pulling force is insufficient. When the lateral spacing between adjacent grooves 12 is too large, the actual weld mark area is too small, resulting in a decrease in the pulling force.

[0087] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A tab structure, characterized in that a welding area (11) is provided on the body (1) of the tab structure (100), wherein The welding area (11) is provided with at least two grooves (12); The welding area (11) comprises a first welding area (13) and a second welding area (14), the number of the grooves (12) arranged transversely in the first welding area (13) is less than the number of the grooves (12) arranged transversely in the second welding area (14); A blank area (16) is arranged between the first welding area (13) and the second welding area (14).

2. The tab structure of claim 1, wherein, When the grooves (12) and the adjacent grooves (12) are arranged transversely, the transverse groove distance between the grooves (12) and the adjacent grooves (12) along the width direction of the welding area (11) is W1; When the grooves (12) and the adjacent grooves (12) are arranged longitudinally, the longitudinal groove distance between the grooves (12) and the adjacent grooves (12) along the length direction of the welding area (11) is W2; Wherein, the range of W1 is 0.5mm-1.5mm, and the range of W2 is 0.2mm-2mm.

3. The tab structure of claim 1, wherein, The first welding area (13) and the second welding area (14) are arranged at intervals, the number of the first welding area (13) is at least one, and the number of the second welding area (14) is at least one.

4. The tab structure of claim 1, wherein, The thickness value of the body (1) is H1, and the depth value of the groove (12) is H2, wherein the value range of H1 is 0.05mm-0.1mm, and the value range of H2 is 0.05mm-0.1mm.

5. The tab structure of claim 4, wherein, The width value of the groove (12) is D1, and the value range of D1 is 0.5mm-0.6mm.

6. The tab structure of claim 5, wherein, The width of the groove (12) increases as it is farther away from the welding surface (15) of the body (1) along the thickness direction of the body (1).

7. The tab structure of claim 1, wherein, The length of the welding area (11) is L1, and the range of L1 is 8mm-10mm; the width of the welding area (11) is L2, and the range of L2 is 3mm-4mm.

8. The tab structure of claim 1, wherein, The groove surface of the groove (12) is rhombic.

9. A pole piece characterized by, A current collector (2) is included, and the surface of the current collector (2) is divided into a coated area (21) and a to-be-welded area (22); The coated area (21) is coated with positive electrode slurry or negative electrode slurry; The to-be-welded area (22) is used for welding with the welding area (11) of the tab structure (100) as claimed in any one of claims 1-8 by a welding device.

10. The pole piece of claim 9, wherein The to-be-welded area (22) is provided with a hollow foil area (221), the position of the hollow foil area (221) corresponds to the groove (12) of the tab structure (100) as claimed in any one of claims 1-8, and the to-be-welded area (22) is coated with slurry outside the hollow foil area (221).

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