Tab structure, pole piece and battery

Abstract

The utility model provides a tab structure, a pole piece and a battery, the tab structure comprises an inner side section, a leading-out section and an overlapping part, along the length direction, the leading-out section is connected to one side of the inner side section, and the width of the leading-out section is smaller than that of the inner side section; in the thickness direction, the overlapping part is connected to one side of the leading-out section and covers part of the leading-out section, the part, not covered by the overlapping part, of the leading-out section is a bridge part, the cross sectional area of the bridge part is smaller than that of the inner side section, and the cross sectional area of the bridge part is smaller than that of the overlapping part overlapped with part of the leading-out section. The pole piece comprises a current collector and the tab structure, and the inner side section is connected to one side of the current collector in the thickness direction. The battery comprises a diaphragm and at least two pole pieces, and the diaphragm is located between the two adjacent pole pieces in the thickness direction. According to the tab structure, the pole piece and the battery, the bridge part can be fused when the tab structure, the pole piece and the battery are subjected to large current, and the safety of electricity utilization is improved.

Description

Technical Field

[0001] This application relates to the technical field of battery production, and particularly relates to an ear structure, a pole piece and a battery. Background Art

[0002] The ear structure includes an inner part connecting the current collector and a lead-out part connecting the inner part. To meet the requirement of the battery for being thinner and lighter and ensure that the ear structure has good current-carrying performance, usually the width of the inner part is increased, the thickness of the inner part is decreased, and the thickness of the lead-out part which is relatively narrower than the inner part is increased. The problem is that when a relatively large current passes through the ear structure, since both the inner part and the lead-out part have good current-carrying performance, the ear structure cannot be melted timely, so that heat will continuously accumulate inside the battery, which is likely to cause safety problems such as battery cracking, leakage and fire. Utility Model Content

[0003] This application aims to solve at least one of the technical problems existing in the prior art. For this purpose, this application provides an ear structure which can improve the safety of power consumption.

[0004] This application also provides a pole piece having the above ear structure.

[0005] This application also provides a battery having the above pole piece.

[0006] The ear structure according to the first aspect embodiment of this application includes an inner segment, a lead-out segment and an overlapping part;

[0007] Along the length direction, the lead-out segment is connected to one side of the inner segment, and the width of the lead-out segment is smaller than that of the inner segment;

[0008] Along the thickness direction, the overlapping part is connected to one side of the lead-out segment to cover part of the lead-out segment. The part of the lead-out segment not covered by the overlapping part is the bridge part. The cross-sectional area of the bridge part is smaller than that of the inner segment, and the cross-sectional area of the bridge part is smaller than the cross-sectional area of the overlapping part and the part of the lead-out segment where they overlap.

[0009] The ear structure according to the embodiment of this application has at least the following beneficial effects: The relatively wide inner segment is provided to improve the current-carrying performance of the inner segment and is beneficial to meet the requirement of the battery for being thinner and lighter. The overlapping part covers part of the lead-out segment to improve the current-carrying performance of part of the area of the lead-out segment. The area of the lead-out segment not covered by the overlapping part forms the bridge part. The current-carrying capacity of the bridge part is smaller than that of the inner segment and smaller than the area of the lead-out segment connected to the overlapping part. The bridge part is used for melting when the current is relatively large, which can effectively block the heat accumulation inside the battery and is beneficial to improving the safety of power consumption.

[0010] According to some embodiments of this application, the ear structure further includes a packaging member, wherein:

[0011] In the thickness direction, the encapsulation member is connected to at least one side of the inner segment. The encapsulation member covers a part of the inner segment and a part of the bridge portion, and the overlapping portion on the same side as the lead-out segment and the encapsulation member have the same thickness;

[0012] In the length direction, the edge of the encapsulation member extends beyond the edge of the inner segment.

[0013] According to some embodiments of the present application, in the length direction, the distance that the edge of the encapsulation member extends beyond the edge of the inner segment is 0.4 mm to 2 mm.

[0014] According to some embodiments of the present application, the thickness of both the inner segment and the lead-out segment is T1, the thickness of the overlapping portion is T2, the width of the inner segment is a, and the widths of the lead-out segment and the overlapping portion are both b, then a×T1 = 0.6×b×(T1 + T2) to 1.4×b×(T1 + T2).

[0015] According to some embodiments of the present application, the overlapping portion and the lead-out segment are welded to form a first welding area. In the length direction, the shortest distance between the first welding area and the inner segment is 0.5 mm to 4 mm.

[0016] According to some embodiments of the present application, the inner segment includes a first conductive portion, a second conductive portion, and a third conductive portion, wherein:

[0017] In the length direction, one side of the first conductive portion is connected to the lead-out segment, and the other side of the first conductive portion is connected to the second conductive portion and the third conductive portion;

[0018] In the width direction, the second conductive portion and the third conductive portion are arranged at intervals, and the width of the first conductive portion is greater than the width of the lead-out segment.

[0019] According to some embodiments of the present application, the inner segment includes a main body portion and a connecting portion, wherein:

[0020] In the width direction, the connecting portion is connected to one side of the main body portion;

[0021] In the length direction, the lead-out segment is connected to one side of the connecting portion, and both the main body portion and the connecting portion are on the same side of the lead-out segment, and the extending dimension of the connecting portion is smaller than the extending dimension of the main body portion.

[0022] According to some embodiments of the present application, the tab structure includes two overlapping portions. In the thickness direction, one of the overlapping portions is connected to one side of the lead-out segment, and the other overlapping portion is connected to the opposite side of the lead-out segment, and both overlapping portions cover a part of the lead-out segment.

[0023] The pole piece according to an embodiment of the present application includes a current collector and the tab structure in any of the above embodiments. In the thickness direction, the inner segment is connected to one side of the current collector.

[0024] The pole piece according to the embodiment of the present application has at least the following beneficial effects: the pole piece structure can fuse the bridge part when the current is large, ensuring the safety of power use. In addition, the setting of the inner section being thinner and wider is beneficial to reducing the thickness of the pole piece and increasing the volumetric energy density of the pole piece.

[0025] The battery according to the embodiment of the present application includes a separator and at least two pole pieces in the above embodiment. In the thickness direction, the separator is located between two adjacent pole pieces.

[0026] The battery according to the embodiment of the present application has at least the following beneficial effects: one of the two pole pieces is used as the negative electrode, and the other pole piece is used as the positive electrode. The separator separates the two pole pieces, preventing the positive electrode and the negative electrode from contacting and causing a short circuit. The pole piece has high safety and volumetric energy density, which is beneficial to ensuring the use safety and volumetric energy density of the battery.

[0027] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present application. Description of the Drawings

[0028] The following further describes the present application with reference to the drawings and embodiments, where:

[0029] Figure 1 is a top view of the tab structure according to the embodiment of the present application;

[0030] Figure 2 is Figure 1 a cross-sectional view taken along line A-A in

[0031] Figure 3 is a schematic structural diagram of the pole piece according to the embodiment of the present application;

[0032] Figure 4 is a top view of the second inner section according to the embodiment of the present application;

[0033] Figure 5 is a cross-sectional view of another tab structure according to the embodiment of the present application;

[0034] Figure 6 is a top view of the third inner section according to the embodiment of the present application.

[0035] Reference numerals: tab structure 100, inner section 110, first conductive part 111, second conductive part 112, third conductive part 113, main body part 114, connecting part 115, second welding area 116, second solder joint 1161, lead-out section 120, bridge part 121, overlapping part 130, first welding area 131, first solder joint 1311, encapsulation part 140;

[0036] pole piece 200, current collector 210. Detailed Embodiments

[0037] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as a limitation of the present application.

[0038] In the description of the present application, it should be understood that with respect to the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying 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 application.

[0039] In the description of the present application, the meaning of several is more than one, the meaning of multiple is more than two, and greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number. If the first and second are described only for the purpose of distinguishing technical features, they should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0040] In the description of the present application, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0041] In the description of the present application, the description referring to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0042] The embodiments of the present application will be introduced below in conjunction with the accompanying drawings of the specification:

[0043] Refer to Figures 1 to 3, according to the tab structure 100 of the embodiment of the present application, it has a set width direction, length direction, and thickness direction, and the width direction, length direction, and thickness direction are perpendicular to each other in pairs. The tab structure 100 includes an inner section 110, a lead-out section 120, and an overlapping section 130. The inner section 110 is used to connect to one side of the current collector 210 along the thickness direction. Along the length direction, the lead-out section 120 is connected to one side of the inner section 110, and the width of the lead-out section 120 is smaller than the width of the inner section 110. The lead-out section 120 and the inner section 110 may have the same thickness. Thus, the lead-out section 120 and the inner section 110 are in the same plane, and there is no layer stacking in the thickness direction between them. Along the thickness direction, the overlapping section 130 is connected to one side of the lead-out section 120 and covers part of the lead-out section 120. The connection of the lead-out section 120 and the overlapping section 130 has a larger cross-sectional area, which is beneficial to ensuring the current-carrying performance of the tab structure 100. At the same time, the part of the lead-out section 120 not covered by the overlapping section 130 is the bridge section 121. The cross-sectional area of the bridge section 121 is smaller than the cross-sectional area of the inner section 110, and the cross-sectional area of the bridge section 121 is also smaller than the cross-sectional area of the overlapping section 130 and the part of the lead-out section 120 that is overlapped. This enables the bridge section 121 to melt timely when the current carried by the tab structure 100 is too large, which is beneficial to improving the safety of power use.

[0044] The above-mentioned cross-sectional area refers to the area of the cross-section formed by transversely cutting each part of the tab structure 100 along a plane perpendicular to the length direction.

[0045] Specifically, the bridge section 121 has the same thickness as the inner section 110 and is relatively narrower than the inner section 110. The width of the overlapping section 130 can be equal to the width of the lead-out section 120. The bridge section 121 is part of the lead-out section 120, and the width of the bridge section 121 is equal to the width of the overlapping section 130. The thickness of the bridge section 121 is less than the sum of the thicknesses of the overlapping section 130 and the lead-out section 120 when they are overlapped. Therefore, when transversely cutting the tab structure 100 along a plane perpendicular to the length direction, the cross-sectional area of the inner section 110 is larger than the cross-sectional area of the bridge section 121, and the cross-sectional area formed by the connection of the lead-out section 120 and the overlapping section 130 is also larger than the cross-sectional area of the bridge section 121. The inner section 110 is used to provide good current-carrying performance, and the structure formed by the connection of the lead-out section 120 and the overlapping section 130 is used to provide good current-carrying performance, which is beneficial to reducing the heat generation of the inner section 110 and the heat generation of the structure formed by the connection of the lead-out section 120 and the overlapping section 130. The cross-sectional area of the bridge section 121 is small and has a large internal resistance. When the current on the tab structure 100 is too large, the bridge section 121 can melt timely, which is beneficial to improving the safety of power use and facilitating better consideration of the current-carrying performance and safety performance of the tab structure 100.

[0046] It should be noted that the inner section 110 and the lead-out section 120 have the same thickness T1, and 0μm < T1 ≤ 70μm. By increasing the width of the inner section 110 and reducing the thickness of the inner section 110, it is beneficial to reduce the thickness after the inner section 110 is connected to the current collector 210 and improve the volumetric energy density of the battery. In addition, the value of T1 can also be any value within any of the intervals of 0μm < T1 ≤ 10μm, 10μm < T1 ≤ 20μm, 20μm < T1 ≤ 30μm, 30μm < T1 ≤ 40μm, 40μm < T1 ≤ 50μm, 50μm < T1 ≤ 60μm, and 60μm < T1 ≤ 70μm. For example, 30μm ≤ T1 ≤ 50μm can be adopted, which is beneficial to reduce the thickness of the battery. And by further limiting the lower limit value of the thickness T1, the problem that the inner section 110 is too thin to be processed and manufactured is effectively avoided.

[0047] Reference Figures 1 to 3 , in some other embodiments, the inner section 110 and the lead-out section 120 are integrally formed. For example, the inner section 110 and the lead-out section 120 can be cut out by a cutting method. Compared with the connection methods such as welding for the inner section 110 and the lead-out section 120, the integrally formed cutting method reduces the stress concentration at the connection of the inner section 110 and the lead-out section 120, making the connection between the inner section 110 and the lead-out section 120 more uniform and reliable. In addition, compared with other connection methods, the step of connecting the inner section 110 and the lead-out section 120 is also omitted, which is beneficial to reducing the production cost.

[0048] Reference Figures 1 to 3 , in some embodiments, the tab structure 100 further includes a packaging member 140. Along the thickness direction, the packaging member 140 is connected to at least one side of the inner section 110. The packaging member 140 covers the edge of the inner section 110 along the length direction close to the lead-out section 120, that is, covers a part of the inner section 110, and, covers a part of the bridge portion 121, and the overlapping portion 130 and the packaging member 140 on the same side of the lead-out section 120 have the same thickness. Along the length direction, the edge of the packaging member 140 at least extends beyond the edge of the inner section 110. The packaging member 140 adheres to the inner section 110 and the lead-out section 120, so that the plane on the side of the packaging member 140 facing away from the inner section 110 is flush with the plane on the side of the overlapping portion 130 facing away from the lead-out section 120. Thus, after heat melting, the packaging member 140 can not only ensure the sealing and reliability of the tab structure 100, but also avoid increasing the overall thickness of the tab structure 100, which is beneficial to improving the volumetric energy density of the battery.

[0049] Specifically, the inner segment 110 and the bridge portion 121 have the same thickness. The encapsulation member 140 covers the inner segment 110 and the bridge portion 121, and the thickness of the encapsulation member 140 is equal to the thickness of the overlapping portion 130, such that the sum of the thicknesses of the inner segment 110 and the encapsulation member 140, the sum of the thicknesses of the inner segment 110 and the bridge portion 121, and the sum of the thicknesses of the lead-out segment 120 and the overlapping portion 130 are all equal. On the basis of ensuring sealing performance and reliability, an increase in the thickness of the tab structure 100 can be avoided.

[0050] Reference Figure 2 , in some other embodiments, along the thickness direction, encapsulation members 140 are connected to both opposite sides of the inner segment 110, and both opposite sides of the bridge portion 121 are covered by the encapsulation members 140, which is beneficial to further improving the sealing performance and reliability of the tab structure 100.

[0051] It should be noted that the encapsulation member 140 has insulating properties and can prevent the tab structure 100 from coming into contact with a metal housing or other metal components and causing a short circuit. Additionally, after the encapsulation member 140 is heat-melted, the tab structure 100 is adhered to other parts, which is beneficial to enhancing the overall stability of the battery structure.

[0052] Reference Figures 1 to 3 , in some embodiments, along the length direction, the distance by which the edge of the encapsulation member 140 extends beyond the edge of the inner segment 110 is 0.4 mm to 2 mm. The encapsulation member 140 is used to fix and seal the tab, defining the outer extension size of the encapsulation member 140, which is used to prevent the outer extension size of the encapsulation member 140 from being too large and interfering with the encapsulation or welding of the battery, and can also prevent problems such as insufficient sealing caused by too small a size of the encapsulation member 140, improving the safety of battery use.

[0053] Specifically, the distance by which the edge of the encapsulation member 140 extends beyond the edge of the inner segment 110 can also be any value within any one of the intervals of 0.4 mm to 0.8 mm, 0.8 mm to 1.2 mm, 1.2 mm to 1.6 mm, and 1.6 mm to 2 mm, so as to better achieve the encapsulation effect of the battery and prevent the outer extension size of the encapsulation member 140 from being too large and affecting the encapsulation effect of the encapsulation member 140.

[0054] It should be noted that the encapsulation member 140 can be CPP glue, and the thickness of the encapsulation member 140 can be consistent with the thickness of the overlapping portion 130 to prevent the encapsulation member 140 from protruding outward relative to the overlapping portion 130 along the thickness direction, which is beneficial to reducing the overall thickness of the tab structure 100.

[0055] Reference Figures 1 to 3, in some embodiments, the thicknesses of the inner segment 110 and the lead-out segment 120 are both T1, the thickness of the overlapping portion 130 is T2, the width of the inner segment 110 is a, and the widths of the lead-out segment 120 and the overlapping portion 130 are both b. Then, a×T1 = 0.6×b×(T1 + T2) to 1.4×b×(T1 + T2). a×T1 is the cross-sectional area of the inner segment 110, and b×(T1 + T2) is the cross-sectional area of the connected part of the lead-out segment 120 and the overlapping portion 130. It should be noted that this part includes the overlapping portion 130 and the part of the lead-out segment 120 other than the bridge portion 121. Thus, a×T1 = 0.6×b×(T1 + T2) to 1.4×b×(T1 + T2) means that the ratio range of the cross-sectional area of the inner segment 110 to the cross-sectional area of the connected part of the lead-out segment 120 and the overlapping portion 130 is from 0.6 to 1.4, which is used to avoid excessive differences in the current-carrying performance of each part of the tab structure 100 and cause waste of the internal space of the battery, and is beneficial to making full use of the characteristics of each part of the tab structure 100 and ensuring the volumetric energy density of the battery.

[0056] Specifically, the above ratio can also be any value within any of the intervals from 0.6 to 0.7, 0.7 to 0.8, 0.8 to 0.9, 0.9 to 1, 1 to 1.1, 1.1 to 1.2, 1.2 to 1.3, and 1.3 to 1.4, which is beneficial to further optimizing the proportion of each part of the tab structure 100. On the basis of meeting the requirement of carrying the normal working current of the battery, the volume of the tab structure 100 can be further reduced, which is beneficial to improving the volumetric energy density of the battery.

[0057] Reference Figures 1 to 3 , in some embodiments, the overlapping portion 130 and the lead-out segment 120 are welded to form the first welding area 131. Along the length direction, the shortest distance between the first welding area 131 and the inner segment 110 is from 0.5 mm to 4 mm. Defining the shortest distance as an interval value facilitates the implementation of the welding operation. Thus, on the basis of ensuring the welding quality, it is beneficial to improve the efficiency of the welding operation. In addition, limiting the lower limit of the shortest distance is used to avoid the heat generated by welding affecting the performance of the inner segment 110, and limiting the upper limit of the shortest distance is used to avoid too long a current transmission path and affecting the charge and discharge efficiency of the battery.

[0058] Specifically, the shortest distance between the first welding area 131 and the inner section 110 can also be any value within any of the intervals of 0.5 mm to 1 mm, 1 mm to 1.5 mm, 1.5 mm to 2 mm, 2 mm to 2.5 mm, 2.5 mm to 3 mm, and 3.5 mm to 4 mm. Defining the lower limit of the shortest distance can effectively avoid the thermal influence and stress concentration influence of the first welding area 131 on the inner section 110, which is beneficial to ensuring the performance of the inner section 110. Furthermore, it facilitates the connection between the inner section 110 and the current collector 210. Defining the upper limit of the shortest distance is used to limit the length of the current transmission path, thereby avoiding the increase in internal resistance caused by the increase in length, which is beneficial to reducing the heat generation of the lead-out section 120 and improving the over-current performance of the lead-out section 120.

[0059] It should be noted that the first welding area 131 may have a plurality of first welding points 1311. The inner section 110 and the lead-out section 120 are connected through the plurality of first welding points 1311. Each first welding point 1311 has a different shortest distance from the inner section 110, and the minimum value among the shortest distances is the shortest distance between the first welding area 131 and the inner section 110.

[0060] Reference Figures 3 to 5 , in some embodiments, the inner section 110 includes a first conductive part 111, a second conductive part 112, and a third conductive part 113. Along the length direction, one side of the first conductive part 111 is connected to the lead-out section 120, and the other side of the first conductive part 111 is connected to the second conductive part 112 and the third conductive part 113. And along the width direction, the second conductive part 112 and the third conductive part 113 are arranged at intervals, and the interval between the second conductive part 112 and the third conductive part 113 is used for coating active materials. The width of the first conductive part 111 is greater than the width of the lead-out section 120, which is used to ensure the over-current performance of the inner section 110. Thus, on the basis of ensuring the over-current performance of the tab structure 100, it helps to further improve the volumetric energy density of the battery.

[0061] Specifically, the width of the first conductive part 111 is the dimension of the first conductive part 111 extending along the width direction. Only when the width of the first conductive part 111 is greater than the width of the lead-out section 120, the dimension of the first conductive part 111 extending along the length direction should be greater than the dimension of the bridge part 121 extending along the length direction, so as to ensure that the current-carrying capacity of the bridge part 121 is the smallest, which is convenient for timely fusing when the current carried by the tab structure 100 is too large and improves the safety of power use.

[0062] It should be noted that along the thickness direction, the side surface of the current collector 210 is coated with active material, and the inner section 110 is also connected to the side surface of the current collector 210. There is a definite accommodation space inside the battery for accommodating the active material and the inner section 110, that is, the sum of the volume of the inner section 110 and the volume of the active material remains fixed. Furthermore, when the volume of the inner section 110 decreases, the volume for accommodating the active material increases correspondingly. On the basis of ensuring the current-carrying performance of the inner section 110, increasing the volume of the active material can improve the volumetric energy density of the battery. Thus, the interval between the second conductive part 112 and the third conductive part 113 can be adaptively adjusted during production and manufacturing to better balance the current-carrying performance of the tab structure 100 and the volumetric energy density of the battery.

[0063] Reference Figures 3 to 5 , in some other embodiments, along the width direction, the sum of the extension dimensions of the second conductive part 112 and the third conductive part 113 is greater than the extension dimension of the lead-out section 120, which is used to ensure the current-carrying performance of the second conductive part 112 and the third conductive part 113, reduce the heat generation of the second conductive part 112 and the third conductive part 113, and the spaced arrangement of the second conductive part 112 and the third conductive part 113 is also beneficial to shortening the current transmission path and improving the charge and discharge efficiency of the battery.

[0064] It should be noted that the limitation of the extension dimensions of the above-mentioned first conductive part 111, second conductive part 112, and third conductive part 113 is used to ensure that the current-carrying performance of all parts outside the bridge part 121 of the tab structure 100 is greater than that of the bridge part 121. In addition to limiting the extension dimensions, it can also be achieved by including but not limited to surface area, volume, and material, etc., so that on the basis of the bridge part 121 carrying the current in the normal working state of the battery, the bridge part 121 can be melted relatively earlier than other regions as the current increases.

[0065] For example, compared with other positions of the tab structure 100, the bridge part 121 can be provided with at least one of a smaller surface area, a smaller volume, and a material with a lower melting point, and the bridge part 121 should ensure that it can carry the current in the normal working state of the battery.

[0066] Reference Figure 3 , Figure 4 and Figure 6, in some embodiments, the inner segment 110 includes a main body portion 114 and a connecting portion 115. Along the width direction, the connecting portion 115 is connected to one side of the main body portion 114. Along the length direction, the lead-out segment 120 is connected to one side of the connecting portion 115. Both the main body portion 114 and the connecting portion 115 are located on the same side of the lead-out segment 120. And along the length direction, the extension dimension of the connecting portion 115 is smaller than that of the main body portion 114. Both the main body portion 114 and the connecting portion 115 are connected to one side of the current collector 210 along the thickness direction. By reducing the extension dimension of the connecting portion 115 relative to the main body portion 114, it is beneficial to increase the coverage area of the active material on the current collector 210, thereby improving the volumetric energy density of the battery. Thus, the arrangement of the main body portion 114 and the connecting portion 115 not only ensures the extension dimension of the inner segment 110 along the width direction but also improves the volumetric energy density of the battery, facilitating better consideration of both the current-carrying capacity of the inner segment 110 and the volumetric energy density of the battery.

[0067] It should be noted that the main body portion 114 and the connecting portion 115 can be formed by cutting the edge of the inner segment 110. Compared with other methods, it is easier to better ensure the stability of the main body portion 114 and the connecting portion 115. On the basis of ensuring that the inner segment 110 meets the current-carrying capacity, a part of the inner segment 110 is cut. After the inner segment 110 is connected to the current collector 210, the corresponding cut position can be coated with active material to improve the volumetric energy density of the battery.

[0068] Reference Figure 5 , in some embodiments, the tab structure 100 includes two overlapping portions 130. Along the thickness direction, one of the overlapping portions 130 is connected to one side of the lead-out segment 120, and the other overlapping portion 130 is connected to the opposite side of the lead-out segment 120. Both of the two overlapping portions 130 cover a part of the lead-out segment 120 and are used to retain the bridge portion 121 to ensure the safety of power utilization. By welding the overlapping portions 130 on the opposite sides of the lead-out segment 120, compared with welding the overlapping portion 130 on one side, it is easier to better disperse the stress generated by welding, which is beneficial to preventing local deformation in the area where the overlapping portion 130 is connected.

[0069] Specifically, the sizes of the two overlapping portions 130 can be the same. Along the thickness direction, the projections of the two overlapping portions 130 on the same plane coincide, which is beneficial to better eliminating the stress generated by welding and avoiding stress concentration.

[0070] Reference Figures 1 to 3, The electrode sheet 200 according to an embodiment of the present application includes a current collector 210 and the tab structure 100 in any of the above embodiments. Along the thickness direction, the inner segment 110 is connected to one side of the current collector 210. The inner segment 110 has a greater width than the lead-out segment 120, and the lamination of the inner segment 110 relative to the lead-out segment 120 and the overlapping portion 130 is thinner. On the basis of ensuring the current-carrying performance of the electrode sheet 200, it is also beneficial to reduce the overall thickness of the electrode sheet 200 and meet the requirement of the battery for being thinner and lighter.

[0071] Specifically, the current collector 210 can be coated with active materials in the area other than the connection with the inner segment 110. For example, when the electrode sheet 200 is used as a positive electrode, it is coated with active materials such as lithium cobaltate and lithium manganate, and when the electrode sheet 200 is used as a negative electrode, it is coated with active materials such as graphite.

[0072] It should be noted that the connection between the inner segment 110 and the current collector 210 can be welding, which can ensure a high connection strength and the connection is more stable and reliable. The inner segment 110 and the current collector 210 are welded to form a second welding area 116. Among them, along the width direction, if the extension dimension of the inner segment 110 is a, then the extension dimension of the second welding area 116 is at least 0.6a, which is used to ensure the connection strength between the inner segment 110 and the current collector 210, beneficial to reducing the internal resistance of the electrode sheet 200 and improving the current transmission efficiency.

[0073] In addition, the width direction of the tab structure 100 is the length direction of the electrode sheet 200 in the unfolded state, the length direction of the tab structure 100 is the width direction of the electrode sheet 200 in the unfolded state, and the thickness direction of the tab structure 100 is the same as the thickness direction of the electrode sheet 200.

[0074] Reference Figures 1 to 3 , In some other embodiments, the second welding area 116 may include a plurality of second solder joints 1161, and the plurality of second solder joints 1161 are spaced apart from each other, which is beneficial to shortening the current transmission path. Along the width direction, the sum of the extension dimensions of each second solder joint 1161 is at least 0.6a, which can effectively reduce the risk of local overheating and stress concentration, and is beneficial to maintaining the structural stability of the battery.

[0075] Reference Figures 1 to 3 , The battery according to an embodiment of the present application includes a separator and at least two electrode sheets 200 in the above embodiments. Among two adjacent electrode sheets 200, one is used as a positive electrode and the other is used as a negative electrode. Along the thickness direction, the separator is located between the two adjacent electrode sheets 200 to separate the positive electrode and the negative electrode and prevent the positive electrode and the negative electrode from contacting and short-circuiting. The thin and light design of the electrode sheet 200 makes the wound or stacked battery thinner and lighter, which is beneficial to improving the volume energy density of the battery.

[0076] The embodiments of the present application have been described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the above embodiments, and various changes can be made without departing from the gist of the present application within the scope of knowledge possessed by those of ordinary skill in the art. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An electrode tab structure has a set width direction, length direction, and thickness direction, and is characterized in that Comprising: Inner section; Lead-out section, along the length direction, the lead-out section is connected to one side of the inner section, and the width of the lead-out section is smaller than the width of the inner section; Overlay section, along the thickness direction, the overlay section is connected to one side of the lead-out section and covers part of the lead-out section. The part of the lead-out section not covered by the overlay section is the bridge section. The cross-sectional area of the bridge section is smaller than the cross-sectional area of the inner section, and the cross-sectional area of the bridge section is smaller than the cross-sectional area of the overlay section overlapping with part of the lead-out section.

2. The tab structure according to claim 1, wherein The tab structure further includes a package, wherein: Along the thickness direction, the package is connected to at least one side of the inner section. The package covers part of the inner section and part of the bridge section, and the overlay section and the package on the same side of the lead-out section have the same thickness; Along the length direction, the edge of the package extends beyond the edge of the inner section.

3. The tab structure according to claim 2, characterized in that, Along the length direction, the distance that the edge of the package extends beyond the edge of the inner section is 0.4 mm to 2 mm.

4. The tab structure according to claim 2, wherein, The thicknesses of the inner section and the lead-out section are both T1, the thickness of the overlay section is T2, the width of the inner section is a, and the widths of the lead-out section and the overlay section are both b, then a×T1 = 0.6×b×(T1 + T2) to 1.4×b×(T1 + T2).

5. The tab structure according to claim 1, characterized in that The overlay section and the lead-out section are welded to form a first welding area. Along the length direction, the shortest distance between the first welding area and the inner section is 0.5 mm to 4 mm.

6. The tab structure according to claim 1, wherein The inner section includes a first conductive part, a second conductive part, and a third conductive part, wherein: Along the length direction, one side of the first conductive part is connected to the lead-out section, and the other side of the first conductive part is connected to the second conductive part and the third conductive part; Along the width direction, the second conductive part and the third conductive part are arranged at intervals, and the width of the first conductive part is greater than the width of the lead-out section.

7. The tab structure according to claim 1, wherein The inner section includes a main body part and a connecting part, wherein: Along the width direction, the connecting part is connected to one side of the main body part; Along the length direction, the lead-out section is connected to one side of the connecting part, and both the main body part and the connecting part are on the same side of the lead-out section. The extension dimension of the connecting part is smaller than the extension dimension of the main body part.

8. The tab structure according to claim 1, characterized in that, The tab structure includes two of the overlay sections. Along the thickness direction, one of the overlay sections is connected to one side of the lead-out section, and the other overlay section is connected to the opposite side of the lead-out section. Both of the overlay sections cover part of the lead-out section.

9. A pole piece, characterized in that, Comprising: Current collector: The tab structure according to any one of claims 1 to 8, along the thickness direction, the inner section is connected to one side of the current collector.

10. A battery, characterized in that, Comprising: Separator; At least two of the electrode plates according to claim 9, along the thickness direction, the separator is located between two adjacent electrode plates.

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