Battery pack and power battery

Abstract

The present invention relates to the technical field of lithium-ion power batteries, and in particular to a battery pole group and a power battery. The end of the battery pole group is formed with a protruding first pole ear portion and a second pole ear portion, the first pole ear portion and the second pole ear portion are arranged on the same side of the battery pole group, and the polarities of the first pole ear portion and the second pole ear portion are opposite; the first pole ear portion is formed into a fan-shaped ring structure, at least part of the second pole ear portion is formed into a ring structure, and the first pole ear portion is arranged outside the ring structure of the second pole ear portion. The battery pole group of the present invention greatly shortens the current flow path on the basis of satisfying sufficient overcurrent, reduces the structural internal resistance and system heat generation, and improves the space utilization rate of the power battery, thereby improving the energy storage capacity of the power battery, and then improves the endurance of the energy storage mechanical equipment, and meets the equipment use requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion power batteries, and in particular to a battery electrode group and a power battery. Background Art

[0002] Lithium-ion batteries are widely used in the new energy industry, such as automobiles, logistics vehicles, and other large mobile energy storage machinery and equipment, due to their large capacity, high operating voltage, long cycle life, and high safety.

[0003] At present, the positive and negative lugs in power batteries extend from different ends of the pole group, and the current is transmitted to the end face through the shell. The internal resistance is high, the system generates a lot of heat, and it is easy to cause accidents such as battery expansion or even explosion. In addition, the pole lug structure is set on both end faces of the pole group, which makes the space utilization rate low, thereby reducing the energy storage capacity of the battery and cannot meet the endurance requirements of energy storage mechanical equipment. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a battery electrode group and a power battery to solve the problem that the positive electrode ear and the negative electrode ear in the existing power battery extend from different ends of the electrode group respectively, resulting in high internal resistance, high system heat generation and low space utilization.

[0005] A first aspect of the present invention provides a battery electrode group, wherein a first electrode ear portion and a second electrode ear portion are formed at an end of the battery electrode group, the first electrode ear portion and the second electrode ear portion are arranged on the same side of the battery electrode group, and the first electrode ear portion and the second electrode ear portion have opposite polarities;

[0006] The first pole lug portion is formed into a fan-shaped ring structure, at least a portion of the second pole lug portion is formed into a ring structure, and the first pole lug portion is arranged outside the ring structure of the second pole lug portion.

[0007] Preferably, the axis of the battery pole group is colinear with the axis of the annular structure of the second pole lug portion.

[0008] Preferably, a plurality of the first pole lug portions are provided, and the plurality of the first pole lug portions are arranged at intervals around the axis of the battery pole group.

[0009] Preferably, the second pole lug portion includes a circular ring portion and a protruding portion, the circular ring portion is formed into the annular structure, the protruding portion extends outward along the side wall of the circular ring portion, and the protruding portion is arranged between two adjacent first pole lug portions.

[0010] Preferably, the radius R1 of the first pole ear portion has a size range of {R 1min =(8~16)~R 1max =23}mm;

[0011] The radius R2 of the annular portion has a size range of {R 2min =4~R 2max =(23-R1-2)}mm; the radius R3 of the protrusion has a size range of {R 3min =(23-R1)~R 3max =23}mm.

[0012] Preferably, the battery pole group is formed into a cylindrical structure by winding pole sheets, and the battery pole group comprises:

[0013] A first pole sheet, wherein the first pole ear portion is formed by winding the first pole sheet, and a plurality of groups of protruding first pole ear portion units are formed at one end of the first pole sheet in the width direction, and the plurality of groups of the first pole ear portion units are arranged at intervals along the length direction of the first pole sheet; the first pole sheet is wound so that the plurality of groups of the first pole ear portion units are stacked along the radial direction of the battery pole group;

[0014] The second pole piece, the second pole ear portion is formed by winding the second pole piece, and a protruding second pole ear circular ring unit and a plurality of groups of second pole ear protruding units are formed at one end of the second pole piece in the width direction, and the plurality of groups of second pole ear protruding units are arranged at intervals along the length direction of the second pole piece; the second pole ear circular ring unit is wound to form the circular ring portion, and the second pole piece is wound so that the plurality of groups of the second pole ear protruding units are stacked along the radial direction of the battery pole group to form the protruding portion.

[0015] Preferably, one end of the first pole piece in the length direction is formed as a first winding starting portion, and the first pole ear unit is arranged on an end of the first pole piece away from the first winding starting portion;

[0016] And / or, one end of the second pole piece in the length direction is formed as a second winding starting portion, the second pole ear ring unit is arranged on an end of the second pole piece close to the second winding starting portion, and the second pole ear protruding unit is arranged on an end of the second pole piece away from the second winding starting portion.

[0017] Preferably, the first pole lug unit comprises first pole lugs arranged one-to-one corresponding to the first pole lug portions, and a plurality of the first pole lugs are arranged at intervals along the length direction of the first pole piece;

[0018] The second pole tab protruding unit includes second pole tabs arranged in one-to-one correspondence with the protruding portions, and a plurality of second pole tabs are arranged at intervals along the length direction of the second pole piece.

[0019] Preferably, the dimension of the first pole lug in the length direction of the first pole piece is L1=π*R1*α / 180°mm, α is 20°-80°; the dimension of the second pole lug in the length direction of the second pole piece is L2=π*R1*β / 180°mm, β is α / 2;

[0020] The spacing dimension between adjacent first pole tabs in each group of the first pole tab units is D1=L2+2*2mm; the spacing dimension between adjacent second pole tabs in each group of the second pole tab protruding units is D2=L1+2*2mm.

[0021] A second aspect of the present invention provides a power battery, comprising a battery pole group as described in any of the above technical solutions, a cover plate and a shell, wherein the battery pole group is arranged in the shell, and the cover plate closes the shell.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The battery electrode group of the present invention, by arranging the first electrode ear portion and the second electrode ear portion with opposite polarities on the same side of the battery electrode group, greatly shortens the current flow path on the basis of satisfying sufficient overcurrent, reduces the structural internal resistance and system heat generation, and improves the space utilization rate of the power battery, thereby improving the energy storage capacity of the power battery, and further improving the endurance of the energy storage mechanical equipment to meet the equipment use requirements.

[0024] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the structure of a battery electrode group provided in an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the structure of a first pole piece in a battery pole group provided in an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the structure of a second pole piece in a battery pole group provided in an embodiment of the present invention;

[0029] Figure 4 A schematic diagram of the structure of a power battery provided in an embodiment of the present invention.

[0030] Icons: 10-battery pole group; 11-first pole ear; 12-second pole ear; 121-annular portion; 122-protruding portion; 110-first pole piece; 111-first winding starting portion; 112-first pole ear unit; 1121-first pole ear; 120-second pole piece; 1201-second winding starting portion; 1202-second pole ear annular unit; 1203-second pole ear protruding unit; 1231-second pole ear; 20-cover plate; 30-shell. DETAILED DESCRIPTION

[0031] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0032] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0033] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0034] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0035] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0036] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0037] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0038] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0039] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0040] According to a first aspect of the present invention, a battery electrode group is provided.

[0041] Hereinafter, a specific structure of the battery electrode group according to the present embodiment will be described.

[0042] In this embodiment, if Figure 1 As shown, a protruding first pole ear portion 11 and a protruding second pole ear portion 12 are formed at the end of the battery pole group 10, and the first pole ear portion 11 and the second pole ear portion 12 are arranged on the same side of the battery pole group 10, thereby saving the space occupied by the pole ear at one end of the battery pole group 10, improving space utilization, and reducing internal resistance.

[0043] In this embodiment, the polarities of the first pole ear portion 11 and the second pole ear portion 12 are opposite, that is, the positive pole ear and the negative pole ear are both arranged at the same side end of the battery electrode group 10. In a preferred embodiment, the first pole ear portion 11 is a positive pole and the second pole ear portion 12 is a negative pole; in another optional embodiment, the first pole ear portion 11 is a negative pole and the second pole ear portion 12 is a positive pole.

[0044] Specifically, in this embodiment, Figure 1 As shown, the battery pole group 10 is formed into a cylindrical structure, the first pole ear portion 11 is formed into a fan-shaped structure, at least part of the second pole ear portion 12 is formed into an annular structure, and the first pole ear portion 11 is arranged around the outer side of the annular structure of the second pole ear portion 12.

[0045] Furthermore, in this embodiment, if Figure 1 As shown, the axis of the battery electrode group 10 is colinear with the axis of the annular structure in the second electrode ear portion 12 , so that the battery electrode group 10 with the second electrode ear portion is formed as an axisymmetric structure as a whole, so as to simplify the preparation process of the battery electrode group 10 .

[0046] In a preferred embodiment, Figure 1 As shown, a plurality of first pole ear portions 11 are provided, and the plurality of first pole ear portions 11 are arranged at intervals around the axis of the battery pole group 10. The number of first pole ear portions 11 is preferably greater than or equal to 3, so that the coverage area of ​​the first pole ear portion 11 on the battery pole group 10 is increased, the current path is also increased accordingly, and electrons are more easily moved inside the battery, so that the speed of charging and discharging is accelerated, and the actual overcurrent efficiency of the system is improved. Further, a plurality of spaced-apart fan-shaped first pole ear portions 11 form an annular structure with an opening, and the second pole ear portion 12 is arranged in the annular structure with an opening formed by the first pole ear portions 11.

[0047] To ensure that the first pole ear portion 11 and the second pole ear portion 12 meet sufficient overcurrent, in this embodiment, Figure 1As shown, the second pole ear portion 12 includes a circular portion 121 and a protruding portion 122, wherein the circular portion 121 is formed into a ring structure, and the first pole ear portion 11 is arranged around the circumferential outer side of the circular portion 121; the protruding portion 122 extends outward along the side wall of the circular portion 121, and the protruding portion 122 is arranged between two adjacent first pole ear portions 11, and the number of the protruding portions 122 is arranged in a one-to-one correspondence with the number of the first pole ear portions 11, so that multiple protruding portions 122 and the first pole ear portions 11 are alternately arranged on the circumferential outer side of the end face of the battery pole group 10.

[0048] Furthermore, in this embodiment, if Figure 1 As shown, the preferred size of the first pole ear portion 11 is: the size range of the radius R1 of the first pole ear portion 11 is {R 1min =(8~16)~R 1max =23}mm; the preferred size of the second pole ear portion 12 is: the size range of the radius R2 of the annular portion 121 is {R 2min =4~R 2max =(23-R1-2)}mm; the size range of the radius R3 of the protrusion 122 is {R 3min =(23-R1)~R 3max =23}mm, the radius R2 of the annular portion 121 and the radius R3 of the protruding portion 122 are restricted and affected by the radius R1 of the first pole ear portion 11, so that the size and shape of the first pole ear portion 11 and the second pole ear portion 12 are reasonably arranged on the battery pole group 10, eliminating the space required for the pole ear at one end of the traditional battery, and having the advantages of low manufacturing cost and high space utilization. It is important that, as defined by the above parameters, the current flow capacity can be optimized, the current flow path is shortened to the greatest extent, and the current loss is reduced, which has the advantages of reducing the internal resistance of the structure and the heat generation of the system, and overcomes the problems of the battery being prone to excessive heating and expansion caused by the long current propagation path and large impedance in the prior art, and reduces the probability of safety accidents such as battery fire and explosion, thereby improving the safety of battery use and extending the battery life.

[0049] In this embodiment, if Figures 1 to 3 As shown, the battery pole group 10 is formed into a cylindrical structure. In a preferred embodiment, the battery pole group 10 is made by a winding process. Specifically, the battery pole group 10 is formed into a cylindrical structure by winding a first pole piece 110 and a second pole piece 120, wherein the first pole ear portion 11 is formed by winding the first pole piece 110, and a plurality of groups of protruding first pole ear units 112 are formed at one end of the first pole piece 110 in the width direction, and the plurality of groups of first pole ear units 112 are arranged at intervals along the length direction of the first pole piece 110; the first pole piece 110 is wound so that the plurality of groups of first pole ear units 112 are stacked along the radial direction of the battery pole group 10.

[0050] Specifically, in this embodiment, Figure 2 As shown, one end of the first pole piece 110 in the length direction is formed as a first winding starting portion 111, and the first pole ear unit 112 is arranged on an end of the first pole piece 110 away from the first winding starting portion 111, so that after winding, the first pole ear portion 11 is arranged on the circumferential outer side of the end face of the battery pole group 10.

[0051] More specifically, in this embodiment, if Figure 2 As shown, the first pole ear unit 112 includes first pole ears 1121 arranged in one-to-one correspondence with the first pole ear portions 11, that is, the number of first pole ears 11 on the battery pole group 10 is the same as the number of first pole ears 1121 in each group of first pole ear units 112, and multiple first pole ears 1121 are arranged at intervals along the length direction of the first pole sheet 110, so that the first pole ears 11 on the battery pole group 10 are surrounded by an open annular structure.

[0052] In addition, in this embodiment, Figure 3 As shown, the second pole ear portion 12 is formed by winding the second pole piece 120, and the second pole piece 120 is formed with a protruding second pole ear ring unit 1202 and a plurality of second pole ear protruding units 1203 at one end in the width direction, and the plurality of second pole ear protruding units 1203 are arranged at intervals along the length direction of the second pole piece 120; the second pole ear ring unit 1202 is wound to form an annular portion 121, and the second pole piece 120 is wound so that the plurality of second pole ear protruding units 1203 are stacked along the radial direction of the battery pole group 10 to form a protruding portion 122.

[0053] Specifically, in this embodiment, Figure 3 As shown, one end of the second pole piece 120 in the length direction is formed as a second winding starting portion 1201, a second pole ear ring unit 1202 is arranged on the second pole piece 120 at one end close to the second winding starting portion 1201, and a second pole ear protruding unit 1203 is arranged on the second pole piece 120 at one end away from the second winding starting portion 1201.

[0054] More specifically, in this embodiment, if Figure 3 As shown, the second pole ear protruding unit 1203 includes second pole ears 1231 arranged in a one-to-one correspondence with the protruding portions 122, that is, the number of protruding portions 122 on the battery pole group 10 is the same as the number of second pole ears 1231 in each group of second pole ear protruding units 1203, and multiple second pole ears 1231 are arranged at intervals along the length direction of the second pole sheet 120, so that each protruding portion 122 on the battery pole group 10 can be arranged between two adjacent first pole ear portions 11.

[0055] It should be noted that when winding to prepare the battery electrode group 10, the first electrode sheet 110 and the second electrode sheet 120 are overlapped and stacked during winding, that is, the first winding starting portion 111 and the second winding starting portion 1201 are aligned, and the first electrode ear 1121 on the stacked first electrode sheet 110 and the second electrode ear 1231 on the second electrode sheet 120 are alternately arranged, so that the first electrode ear portion 11 and the protrusion 122 on the circumferential outer side of the battery electrode group 10 after winding can be alternately arranged with each other.

[0056] In addition, in this embodiment, Figure 2 and Figure 3 As shown, the dimension of the first pole ear 1121 in the length direction of the first pole sheet 110 is L1=π*R1*α / 180°mm, α is 20°~80°; the dimension of the second pole ear 1231 in the length direction of the second pole sheet 120 is L2=π*R1*β / 180°mm, β is α / 2; wherein R1 is the radius of the first pole ear portion 11; the spacing dimension of adjacent first pole ears 1121 in each group of first pole ear unit 112 is D1=L2+2*2mm; the spacing dimension of adjacent second pole ears 1231 in each group of second pole ear protruding unit 1203 is D2=L1+2*2mm; in this way, after the first pole sheet 110 and the second pole sheet 120 are wound, the end of the battery pole group 10 is formed as shown in the figure. Figure 1 The structural shape of the first pole ear portion 11 and the second pole ear portion 12 shown, and the size of the first pole ear 1121 in the length direction of the first pole sheet 110 is L1, and the size of the second pole ear 1231 in the length direction of the second pole sheet 120 is L2, are all constrained by the radius R1 of the first pole ear portion 11, so that the size and shape of the first pole ear portion 11 and the second pole ear portion 12 formed by the first pole sheet 110 and the second pole sheet 120 after winding meet the parameter range limitation requirements of the above R1, R2 and R3, thereby ensuring that the current flow capacity of the battery pole group 10 formed after the first pole sheet 110 and the second pole sheet 120 are wound is optimal, and the current flow path is shortened to the greatest extent and the current loss is reduced, which has the advantages of reducing the structural internal resistance and the heat generation of the system, and overcomes the problems of excessive heating and expansion of the battery caused by the long current propagation path and large impedance in the prior art, and reduces the probability of safety accidents such as battery fire and explosion, thereby improving the safety of battery use and extending the battery life.

[0057] According to a battery pole group provided by the present invention, by arranging the first pole ear portion and the second pole ear portion with opposite polarities on the same side of the battery pole group, on the basis of ensuring sufficient overcurrent, the current flow path is shortened to the greatest extent, the structural internal resistance and the system heat generation are reduced, thereby extending its service life and improving the safety of battery use.

[0058] According to a second aspect of the present invention, a power battery is provided, comprising the battery electrode group provided in the above embodiment, as well as the cover plate 20 and the housing 30. Specifically, in this embodiment, Figure 4 As shown, the battery pole group is arranged in a housing 30 , and the cover plate 20 closes the housing 30 , so that the battery pole group is arranged in the closed housing 30 .

[0059] According to a power battery provided by the present invention, by arranging the pole ears on the battery pole group on the same side, the current flow path is greatly shortened, the structural internal resistance and system heat generation are reduced, and the space utilization rate of the power battery is improved, thereby improving the energy storage capacity of the power battery, thereby improving the endurance of the energy storage mechanical equipment and meeting the equipment use requirements.

[0060] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery electrode group, characterized in that: The end of the battery electrode group is formed with a protruding first electrode ear portion and a second electrode ear portion, the first electrode ear portion and the second electrode ear portion are arranged on the same side of the battery electrode group, and the polarities of the first electrode ear portion and the second electrode ear portion are opposite; The first pole ear portion is formed into a fan-shaped ring structure, at least part of the second pole ear portion is formed into a ring structure, the first pole ear portion is arranged outside the ring structure of the second pole ear portion; a plurality of the first pole ear portions are provided, and the plurality of the first pole ear portions are arranged at intervals around the axis of the battery pole group; the second pole ear portion includes a circular ring portion and a protruding portion, the circular ring portion is formed into the ring structure, the protruding portion extends outward along the side wall of the circular ring portion, and the protruding portion is arranged between two adjacent first pole ear portions; The radius R1 of the first pole ear portion has a size range of {R 1min =(8~16)~R 1max =23} mm; The radius R2 of the annular portion has a size range of {R 2min =4~R 2max =(23-R1-2)} mm; the size range of the radius R3 of the protrusion is {R 3min =(23-R1)~R 3max =23} mm.

2. The battery electrode group according to claim 1, characterized in that: The axis of the battery pole group is colinear with the axis of the annular structure of the second pole ear portion.

3. The battery electrode group according to claim 1, characterized in that: The battery pole group is formed into a cylindrical structure by winding pole sheets, and the battery pole group includes: A first pole sheet, wherein the first pole ear portion is formed by winding the first pole sheet, and a plurality of groups of protruding first pole ear portion units are formed at one end of the first pole sheet in the width direction, and the plurality of groups of the first pole ear portion units are arranged at intervals along the length direction of the first pole sheet; the first pole sheet is wound so that the plurality of groups of the first pole ear portion units are stacked along the radial direction of the battery pole group; The second pole piece, the second pole ear portion is formed by winding the second pole piece, and a protruding second pole ear circular ring unit and a plurality of groups of second pole ear protruding units are formed at one end of the second pole piece in the width direction, and the plurality of groups of second pole ear protruding units are arranged at intervals along the length direction of the second pole piece; the second pole ear circular ring unit is wound to form the circular ring portion, and the second pole piece is wound so that the plurality of groups of the second pole ear protruding units are stacked along the radial direction of the battery pole group to form the protruding portion.

4. The battery electrode group according to claim 3, characterized in that: One end of the first pole piece in the length direction is formed as a first winding starting portion, and the first pole lug unit is arranged on an end of the first pole piece away from the first winding starting portion; And / or, one end of the second pole piece in the length direction is formed as a second winding starting portion, the second pole ear ring unit is arranged on an end of the second pole piece close to the second winding starting portion, and the second pole ear protruding unit is arranged on an end of the second pole piece away from the second winding starting portion.

5. The battery electrode group according to claim 3, characterized in that: The first pole lug unit includes first pole lugs arranged one by one corresponding to the first pole lug portions, and a plurality of the first pole lugs are arranged at intervals along the length direction of the first pole piece; The second pole tab protruding unit includes second pole tabs arranged in one-to-one correspondence with the protruding portions, and a plurality of second pole tabs are arranged at intervals along the length direction of the second pole piece.

6. The battery electrode group according to claim 5, characterized in that: The dimension of the first pole tab in the length direction of the first pole piece is L1=π*R1*α / 180°mm, α is 20° to 80°; the dimension of the second pole tab in the length direction of the second pole piece is L2=π*R1*β / 180°mm, β is α / 2; The spacing dimension between adjacent first pole tabs in each group of the first pole tab units is D1=L2+2*2mm; the spacing dimension between adjacent second pole tabs in each group of the second pole tab protruding units is D2=L1+2*2mm.

7. A power battery, characterized in that: The invention comprises the battery pole group as claimed in any one of claims 1 to 6, a cover plate and a shell, wherein the battery pole group is arranged in the shell, and the cover plate closes the shell.

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