Battery monomer and battery pack

Abstract

The utility model provides a battery monomer and a battery pack, and relates to the technical field of batteries. Each battery monomer comprises a roll core and a collector plate; the current collecting plate is welded with the tab layer of the roll core according to the preset welding track, the first end of the preset welding track is located between the root and the end of the first circle of tab, the second end of the preset welding track is located between the root and the end of the Nth circle of tab, one of the first end and the second end serves as a welding starting point, and the other end serves as a welding ending point; according to the present invention, the current collector plate is electrically connected with the tab, and the following conditions are satisfied: 0.95 D1 < = s < = 0.99 D1, and 1.01 dN < = f < = 1.05 dN, such that each circle of the tab can be electrically connected with the current collector plate through the short welding path so as to reduce the influence of the low inner ring and the low outer ring of the tab layer and the high middle plane on the welding quality, further improve the cycle life of the battery monomer, and reduce the short circuit risk of the battery monomer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer and a battery pack. BACKGROUND

[0002] The winding core of the cylindrical battery monomer usually adopts a full-tab design, that is, the tabs at the end of the winding core are stacked to form a tab layer through rubbing or cutting and flattening processes, and then the current collector disc is welded with the tab layer to realize electrical connection. The winding core has the first tab to the Nth tab from the inner ring to the outer ring. In order to ensure that each tab can be electrically connected with the current collector disc, the current collector disc is welded with the tab layer according to a preset welding track. The starting point of the welding track is aligned with the end position of the first tab, and the ending point of the welding track is aligned with the root position of the Nth tab.

[0003] However, the tab layer stacked in this way has a low inner ring and a low outer ring, and a high middle plane. The welding span of the above welding track is large, the current is uneven, the internal resistance is increased, and the cycle life of the battery monomer is reduced. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the purpose of the present application is to provide a battery monomer and a battery pack, which aims to solve the technical problem of how to improve the cycle life.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the embodiments of the present application provide a battery monomer, comprising:

[0007] a winding core in a cylindrical shape and having a central hole, the winding core having N tabs at one end in the center line direction of the central hole, N≥2, the first tab to the Nth tab being sequentially and spacedly distributed from the side close to the central hole to the direction away from the central hole, a part of each tab being bent towards the direction close to the central hole, so that there is a stacking area between any two adjacent tabs to form a tab layer, the side close to the central hole of each tab being an end, and the side away from the central hole of each tab being a root;

[0008] a current collector disc located at the side of the winding core having the tab layer, the current collector disc being welded with the tab layer according to a preset welding track, the preset welding track having a first end and a second end, the first end being located between the root and the end of the first tab, the second end being located between the root and the end of the Nth tab, the diameter at the position corresponding to the first end of the first tab being s, the diameter at the position corresponding to the second end of the Nth tab being f, the diameter at the root position of the first tab being D1, and the diameter at the end position of the Nth tab being dN ;

[0009] Wherein, when the current collector plate is welded with the tab layer, 0.95D1≤s≤0.99D1, 1.01d N ≤f≤1.05d N , so that each of the tabs is electrically connected with the current collector plate.

[0010] In one of the embodiments of the first aspect, the diameter of the root position of the Nth tab is D N , the diameter of the winding core is D, and 0.95D≤D N ≤0.999D is satisfied.

[0011] In one of the embodiments of the first aspect, 4mm≤D1≤18mm is satisfied.

[0012] In one of the embodiments of the first aspect, 7mm≤D1≤12mm is satisfied.

[0013] In one of the embodiments of the first aspect, the diameter of the end position of the first tab is d1, and 3mm≤d1≤8mm is satisfied.

[0014] In one of the embodiments of the first aspect, 4mm≤d1≤6mm is satisfied.

[0015] In one of the embodiments of the first aspect, the diameter of the root position of the Nth tab is D N , the diameter of the winding core is D, and in the direction perpendicular to the center line of the center hole, the distance between the end of the first tab and the root is H, and 2H=D N -d N , 1mm≤H≤10mm.

[0016] In one of the embodiments of the first aspect, 3mm≤H≤6mm is satisfied.

[0017] In one of the embodiments of the first aspect, a plurality of preset welding tracks are provided, and at least two of the preset welding tracks are arranged at intervals; the preset welding track is one or a combination of more than one of a straight line track, a spiral line track, a spot welding track, a parabolic line track, and a sinusoidal line track.

[0018] In a second aspect, the embodiments of the present application also provide a battery pack comprising the battery cell of any one of the embodiments of the first aspect.

[0019] The beneficial effects of the present application are:

[0020] The battery cell provided in the application, since the current collector plate is welded with the tab layer according to the preset welding track, the first end of the preset welding track is located between the root and the end of the first tab, the second end of the preset welding track is located between the root and the end of the Nth tab, one of the first end and the second end is taken as the welding starting point and the other is taken as the welding ending point, and the following conditions are met: 0.95D1≤s≤0.99D1, 1.01d N ≤f≤1.05d N In this way, each tab is electrically connected with the current collector plate through a shorter welding path, so that the influence of the condition that the inner and outer tabs in the tab layer are low and the middle plane is high on the welding quality is reduced, and the cycle life of the battery cell is improved, and the risk of short circuit of the battery cell is also reduced.

[0021] In order to make the above-mentioned purposes, characteristics and advantages of the application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 A perspective view of a winding core in the related art is shown;

[0024] Figure 2 A schematic diagram showing the relationship between the stacking height and the number of turns of the tab layer in the related art is shown;

[0025] Figure 3 A cross-sectional structure schematic diagram of the winding core and the current collector plate in the explosion state in some embodiments of the application is shown;

[0026] Figure 4 A structure schematic diagram of Figure 3 part A in the application is shown;

[0027] Figure 5 A perspective view of a winding core in some embodiments of the application is shown.

[0028] Main element symbol explanation:

[0029] Main element symbol explanation in the related art: 200-winding core; 210-tab; 211-end; 212-root; 220-welding track; 221-starting point; 222-ending point; 230-center hole;

[0030] Main element symbol explanation in the present application: 110 - winding core; 111 - positive electrode sheet; 112 - negative electrode sheet; 1121 - sheet body; 1122 - tab; 11221 - end portion; 11222 - root portion; 113 - separator; 114 - center hole; 115 - tab layer; 120 - current collector; 130 - preset welding track; 131 - first end; 132 - second end. DETAILED DESCRIPTION

[0031] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only, for the purpose of explanation, and are not to be understood as limiting the present application.

[0032] In the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0033] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0034] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an 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 meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature is "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0036] Cylindrical battery cells have been widely used in the field of new energy vehicles due to their low internal resistance, high energy density, high safety performance and other advantages. The winding core of the cylindrical battery cell usually adopts a full tab design, that is, the tabs at the end of the winding core are stacked to form a tab layer through rubbing or cutting and flattening process, and then the current collector disc is welded with the tab layer to realize electrical connection.

[0037] As shown in Figure 1 and Figure 2 , the winding core 200 starts from the position of the center hole 230, and has the first to Nth tabs 210 from the inner ring to the outer ring. In order to ensure that each tab 210 can be electrically connected with the current collector disc, the current collector disc is welded with the tab layer according to the preset welding track 220. The starting point 221 of the welding track 220 is aligned with the position of the end 211 of the first tab 210, and the ending point 222 of the welding track 220 is aligned with the position of the root 212 of the Nth tab 210.

[0038] However, the tab layer stacked will present the situation of low inner ring and outer ring, and high middle plane. The welding span of the above welding track is large, and abnormal conditions such as virtual welding and burning of the separator are easy to occur, which increases the risk of short circuit. At the same time, the current is uneven, which increases the internal resistance and reduces the cycle life of the battery cell.

[0039] In order to solve the above technical problems, in a first aspect, embodiments of the present application provide a battery cell, relating to the technical field of batteries, mainly applied in a battery pack, and applied in an electric device such as a vehicle, a ship, a spacecraft, or an energy storage device such as an energy storage container and an energy storage power station in the form of a battery pack.

[0040] Of course, the battery cell can also be directly applied in the electric device or the energy storage device without adopting the form of the battery pack, and the application scenarios of the battery cell are not specifically limited here.

[0041] As shown in Figures 3 to 5As shown, the battery cell provided by the embodiment includes a winding core 110 and a current collector plate 120. The winding core 110 is in a cylindrical shape and has a central hole 114. The winding core 110 has N (N≥2) layers of tabs 1122 at one end in the center line direction of the central hole 114. The first layer of tabs 1122 to the Nth layer of tabs 1122 are sequentially and spaced apart from each other in a direction away from the central hole 114 from a side close to the central hole 114. A part of each layer of tabs 1122 is bent in a direction close to the central hole 114, so that a stacking area is formed between any two adjacent layers of tabs 1122 to form a tab layer 115. A side of each layer of tabs 1122 close to the central hole 114 is an end portion 11221, and a side of each layer of tabs 1122 away from the central hole 114 is a root portion 11222.

[0042] The current collector plate 120 is located at a side of the winding core 110 having the tab layer 115, and the current collector plate 120 is welded with the tab layer 115 according to a preset welding track 130. The preset welding track 130 has a first end 131 and a second end 132. The first end 131 is located between the root portion 11222 and the end portion 11221 of the first layer of tabs 1122, and the second end 132 is located between the root portion 11222 and the end portion 11221 of the Nth layer of tabs 1122. A diameter of a position of the first layer of tabs 1122 corresponding to the first end 131 is s, a diameter of a position of the Nth layer of tabs 1122 corresponding to the second end 132 is f, a diameter of a position of the root portion 11222 of the first layer of tabs 1122 is D1, and a diameter of a position of the end portion 11221 of the Nth layer of tabs 1122 is d. N .

[0043] In the welding of the current collector plate 120 with the tab layer 115, the following conditions are met: 0.95D1≤s≤0.99D1, 1.01d N ≤f≤1.05d N , so that each layer of tabs 1122 is electrically connected with the current collector plate 120.

[0044] It should be noted that the diameter s of the position of the first layer of tabs 1122 corresponding to the first end 131 is the diameter of the position of the first layer of tabs 1122 directly opposite the first end 131 along the center line direction of the central hole 114, which is between the end portion 11221 and the root portion 11222 of the first layer of tabs 1122, i.e., d1

[0045] It should be noted that the diameter f of the position of the Nth layer of tabs 1122 corresponding to the second end 132 is the diameter of the position of the Nth layer of tabs 1122 directly opposite the second end 132 along the center line direction of the central hole 114, which is between the end portion 11221 and the root portion 11222 of the Nth layer of tabs 1122, i.e., d N <f<D N , DN It is the diameter at the root position 11222 of the Nth loop pole tab 1122.

[0046] For example, the core 110 includes a positive electrode 111, a negative electrode 112, and a separator 113. Both the positive electrode 111 and the negative electrode 112 include connected sheet bodies 1121 and tabs 1122. The separator is located between the sheet bodies 1121 of the positive electrode 111 and the sheet bodies 1121 of the negative electrode 112, and is used to separate the sheet bodies 1121 of the positive electrode 111 and the sheet bodies 1121 of the negative electrode 112.

[0047] It is understood that in the battery cell provided in this embodiment, since the current collector 120 is welded to the tab layer 115 according to the preset welding trajectory 130, the first end 131 of the preset welding trajectory 130 is located between the root 11222 and the end 11221 of the first loop tab 1122, and the second end 132 of the preset welding trajectory 130 is located between the root 11222 and the end 11221 of the Nth loop tab 1122. One end of the first end 131 and the second end 132 serves as the welding start point and the other end serves as the welding end point, and satisfies: 0.95D1≤s≤0.99D1, 1.01d N ≤f≤1.05d N This allows each tab 1122 to be electrically connected to the current collector 120 with a shorter welding path, thereby reducing the impact of the lower inner and outer rings and higher middle plane of the tab layer 115 on the welding quality, thus improving the cycle life of the battery cell and reducing the risk of short circuit in the battery cell.

[0048] like Figures 3 to 5 As shown, in one embodiment, the diameter of the root 11222 of the Nth loop tab 1122 is D. N The diameter of core 110 is D, which satisfies the relationship: 0.95D≤D N ≤0.999D.

[0049] For example, 20mm≤D≤80mm, where D can be any value from 20mm, 22mm, 25mm, 26mm, 27.6mm, 29mm, 30mm, 32mm, 32.3mm, 35mm, 36mm, 40mm, 42mm, 45mm, 49mm, 50mm, 55mm, 58mm, 60mm, 62mm, 65mm, 66mm, 70mm, 72mm, 74mm, 78mm, 80mm or any value from a range of two of these values, without any specific limitation.

[0050] For example, D NYou can choose any value from 0.95D, 0.96D, 0.966D, 0.97D, 0.975D, 0.98D, 0.99D, 0.993D, 0.995D, 0.999D, or any value from a range of any two of them; there are no specific restrictions here.

[0051] It is understandable that the diameter D at the root 11222 position of the Nth loop pole tab 1122 is... N Maintaining the D value between 0.95D and 0.999D is beneficial for improving the cycle life of individual battery cells.

[0052] like Figures 3 to 5 As shown, in one embodiment, the following condition is satisfied: 4mm≤D1≤18mm.

[0053] For example, the diameter D1 at the root 11222 position of the first loop tab 1122 can be any value of 4mm, 5mm, 6mm, 7mm, 8mm, 10mm, 11mm, 12mm, 15mm, 17mm, 18mm or any value within a range of any two of these, without any specific limitation.

[0054] It is understandable that by controlling the diameter D1 of the root 11222 of the first loop tab 1122 within the range of 4mm to 18mm, it is beneficial to improve the cycle life of the battery cell.

[0055] like Figures 3 to 5 As shown, further, it satisfies: 7mm≤D1≤12mm.

[0056] For example, the diameter D1 at the root 11222 position of the first loop tab 1122 can be any value of 7mm, 7.2mm, 8mm, 8.5mm, 9mm, 9.4mm, 10mm, 10.7mm, 11mm, 12mm or any value within the range of any two of them, and no specific limitation is made on the diameter D1 here.

[0057] It is understandable that by controlling the diameter D1 of the root 11222 of the first loop tab 1122 within the range of 7mm to 12mm, it is beneficial to further improve the cycle life of the battery cell.

[0058] like Figures 3 to 5 As shown, in one embodiment, the diameter of the end 11221 of the first loop tab 1122 is d1, which satisfies: 3mm≤d1≤8mm.

[0059] Exemplarily, the diameter d1 of the end portion 11221 of the first circle of the tab 1122 can be selected as any value in the range of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or any value in the range formed by any two of them, without specific limitation here.

[0060] It can be understood that by controlling the diameter d1 of the end portion 11221 of the first circle of the tab 1122 in the range of 3mm to 8mm, the cycle life of the battery monomer is improved.

[0061] As shown in Figures 3 to 5 , further, the relationship 4mm≤d1≤6mm is satisfied.

[0062] Exemplarily, the diameter d1 of the end portion 11221 of the first circle of the tab 1122 can be selected as any value in the range of 4mm, 4.2mm, 4.4mm, 4.5mm, 5mm, 5.1mm, 5.5mm, 6mm, or any value in the range formed by any two of them, without specific limitation here.

[0063] It can be understood that by controlling the diameter d1 of the end portion 11221 of the first circle of the tab 1122 in the range of 4mm to 6mm, the cycle life of the battery monomer is further improved.

[0064] As shown in Figures 3 to 5 , in one embodiment, the diameter of the root portion 11222 of the Nth circle of the tab 1122 is D N , the diameter of the winding core 110 is D, the distance between the end portion 11221 and the root portion 11222 of the first circle of the tab 1122 in the direction perpendicular to the center line of the center hole 114 is H, and the relationship 2H=D N -d N , 1mm≤H≤10mm is satisfied.

[0065] Exemplarily, the distance H between the end portion 11221 and the root portion 11222 of the first circle of the tab 1122 can be selected as any value in the range of 1mm, 2mm, 3mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.2mm, 7mm, 7.3mm, 8mm, 9mm, 10mm, or any value in the range formed by any two of them, without specific limitation here.

[0066] It can be understood that by making the battery monomer satisfy the relationship 2H=D N -d NThat is, the distance between the end 11221 and the root 11222 of the first circle of the tab 1122 is the same as the distance between the end 11221 and the root 11222 of the Nth circle of the tab 1122, and the distance is controlled to be in the range of 1mm-10mm, which can improve the condition that the inner and outer circles of the tab layer 115 are low and the middle plane is high, so that the height change of the tab layer 115 is more gentle, so as to reduce the influence on the welding quality, thereby improving the cycle life of the battery monomer.

[0067] As shown in Figures 3 to 5 Further, the battery monomer satisfies the following relationship: 3mm≤H≤6mm.

[0068] Exemplarily, the distance H between the end 11221 and the root 11222 of the first circle of the tab 1122 can be selected as any value in 3mm, 3.2mm, 3.5mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.1mm, 5.5mm, 5.6mm, 6mm or any range formed by any two of them, which is not specifically limited here.

[0069] It can be understood that by controlling the distance H between the end 11221 and the root 11222 of the first circle of the tab 1122 to be in the range of 3mm-6mm, the cycle life of the battery monomer can be further improved.

[0070] In one embodiment, the plurality of preset welding tracks 130 are provided, and at least two preset welding tracks 130 are arranged at intervals, that is, at least two preset welding tracks 130 are arranged at intervals in the plurality of preset welding tracks 130, which can improve the welding quality between the winding core 110 and the current collector plate 120.

[0071] Optionally, the plurality of preset welding tracks 130 can be distributed at intervals along the circumference of the winding core 110, so that the welding between the tab 1122 and the current collector plate 120 is more balanced and stable, and the product quality is improved.

[0072] It should be noted that the preset welding track 130 can be one or a combination of a straight line track, a spiral line track, a spot welding track, a parabolic line track, and a sinusoidal line track, and the type of the preset welding track 130 is not specifically limited here.

[0073] In a second aspect, the embodiments of the present application provide a battery pack comprising the battery monomer in any of the embodiments of the first aspect.

[0074] It can be understood that since the battery pack provided by the present embodiment has the battery monomer in any of the embodiments of the first aspect, it has all the beneficial effects of the battery monomer, which will not be described here.

[0075] Optionally, the battery pack comprises at least two aforementioned battery monomers. The at least two battery monomers can be connected in parallel, in series, or in both parallel and series, to meet the actual power output requirement.

[0076] In order to better illustrate the beneficial effects of the embodiments of the present application, the cycle life test results of the battery monomer are shown in the following table.

[0077]

[0078] I. Size measurement method: D, H, d1, D1, d N , D N The same size can be measured by an electronic size test microscope, which can directly display the point position value through a computer; or a straight tooth can be used for measurement.

[0079] II. Cycle life test method: the initial capacity of the battery monomer is C0(Ah), in an environment temperature of 25±3℃, first, charge to the upper limit cutoff voltage using 1C0, and then charge to 0.05C0 cutoff voltage in constant current and constant voltage; second, stand for 60min; third, discharge to the lower limit cutoff voltage using 1C0; fourth, stand for 60min; repeat the first to fourth steps for cycle test, and when the cycle discharge capacity / initial capacity is less than 70%, the number of times is recorded as the cycle life of the battery monomer.

[0080] III. Cycle life test pass standard: cycle life≥1000 times.

[0081] IV. Test results: in Comparative Example 1, s=D1, f=d N , that is, the welding starting point is aligned with the end portion 11221 of the first circle of the tab 1122, and the welding end point is aligned with the root portion 11222 of the Nth circle of the tab 1122, at this time the cycle life is 500 times, and the test fails; in Examples 1 to 4, the welding starting point is located between the end portion 11221 and the root portion 11222 of the first circle of the tab 1122, and satisfies 0.95D1≤s≤0.99D1, the welding end point is located between the end portion 11221 and the root portion 11222 of the Nth circle of the tab 1122, and satisfies: 1.01d N ≤f≤1.05d N , cycle life≥1000 times, and the test passes.

[0082] In Examples 5 and 6, 0.95D≤D N≤0.999D, the cycle life is ≥1000 times, and the test passes. In Embodiments 7 to 10, 4mm≤D1≤18mm is satisfied, the cycle life is all ≥1000 times, and the test passes. In Embodiments 11 to 14, 3mm≤d1≤8mm is satisfied, the cycle life is all ≥1000 times, and the test passes. In Embodiments 15 to 19, 2H=D N -d N , and 1mm≤H≤10mm is satisfied, the cycle life is all ≥1000 times, and the test passes.

[0083] However, in Comparative Example 2, since 1.01d N ≤f≤1.05d N , the cycle life is less than 1000 times, and the test fails; in Comparative Example 3, since 0.95D1≤s≤0.99D1 is not satisfied, the cycle life is less than 1000 times, and the test fails; in Comparative Example 4, since 3mm≤d1≤8mm and 4mm≤D1≤18mm are not satisfied, the cycle life is less than 1000 times, and the test fails.

[0084] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. Illustrative expressions of the above terms in the present specification do not necessarily refer to the same embodiment or example. Also, the specific feature, structure, material or characteristic described can be combined in suitable ways in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0085] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A battery cell, characterized by, Comprising: A roll core (110) in a cylindrical shape and having a center hole (114), the roll core (110) having N pole tabs (1122) at one end in the center line direction of the center hole (114), N≥2, the 1st to Nth pole tabs (1122) being sequentially and spaced apart from each other in a direction away from the center hole (114) from a side close to the center hole (114), a part of each of the pole tabs (1122) being bent in a direction close to the center hole (114) so that there is a stacking area between any two adjacent pole tabs (1122) to form a pole tab layer (115), and each of the pole tabs (1122) having an end portion (11221) close to the center hole (114) and a root portion (11222) away from the center hole (114); A current collecting plate (120) is located on the side of the winding core (110) with the tab layer (115), the current collecting plate (120) is welded with the tab layer (115) according to a preset welding track (130), the preset welding track (130) has a first end (131) and a second end (132), the first end (131) is located between the root (11222) and the end (11221) of the first tab (1122), the second end (132) is located between the root (11222) and the end (11221) of the Nth tab (1122), the diameter of the first tab (1122) at the position corresponding to the first end (131) is s, the diameter of the Nth tab (1122) at the position corresponding to the second end (132) is f, the diameter of the root (11222) of the first tab (1122) is D1, and the diameter of the end (11221) of the Nth tab (1122) is d N ; Wherein, when the current collecting plate (120) is welded with the tab layer (115), 0.95D1≤s≤0.99D1, 1.01d N ≤f≤1.05d N So that each of the tabs (1122) is electrically connected with the current collecting plate (120).

2. The battery cell of claim 1, wherein, The diameter of the root (11222) position of the Nth circle of the tab (1122) is D N , the diameter of the core (110) is D, and 0.95D ≤ D N ≤ 0.999D is satisfied.

3. The battery cell of claim 1, wherein, 4mm≤D1≤18mm is satisfied.

4. The battery cell of claim 3, wherein, 7mm≤D1≤12mm is satisfied.

5. The battery cell of claim 1, wherein, The diameter of the end portion (11221) of the 1st pole tab (1122) is d1, and 3mm≤d1≤8mm is satisfied.

6. The battery cell of claim 5, wherein, 4mm≤d1≤6mm is satisfied.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The diameter of the position of the root (11222) of the Nth polar lug (1122) is D N The diameter of the core (110) is D, and the distance between the end (11221) and the root (11222) of the 1st polar lug (1122) in the direction perpendicular to the center line direction of the center hole (114) satisfies: 2H=D N -d N 1mm≤H≤10mm.

8. The battery cell of claim 7, wherein, 3mm≤H≤6mm is satisfied.

9. The battery cell of any one of claims 1 to 6, wherein, The preset welding track (130) is provided with a plurality of tracks, and at least two of the preset welding tracks (130) are arranged at intervals; the preset welding track (130) is one or a combination of more than one of a straight line track, a spiral line track, a spot welding track, a parabolic line track, and a sinusoidal line track.

10. A battery pack, characterized by, The battery cell of any one of claims 1 to 9 is included.

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