Secondary battery central tube structure and secondary battery

Abstract

The present application relates to the field of battery technology, and discloses a secondary battery central tube structure and a secondary battery, wherein the secondary battery central tube structure comprises: a tube body and a pair of support parts. The tube body is suitable for being inserted into the central through hole of the battery cell. A pair of support parts are respectively sleeved on the opposite ends of the tube body, and a pair of support parts are suitable for being respectively installed at the opposite ends of the central through hole and fitting with the pole ear area of ​​the battery cell. The tube body provided in the present application is inserted into the central through hole of the secondary battery cell to serve as an internal support of the battery cell, release the internal tension of the battery cell, and improve the stability of the battery cell. In addition, a pair of support parts are respectively installed at the opposite ends of the central through hole and fit with the pole ear area, which can effectively support the pole ear area of ​​the battery cell, prevent the pole ear area from being flattened and then inserted or torn, reduce the probability of short circuit defects in the battery cell, and further improve the stability and safety of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a central tube structure of a secondary battery and a secondary battery. Background Art

[0002] During the charge and discharge cycle, the cell of the secondary battery is easily expanded into the cell due to the rebound of the electrode thickness, causing the cell to collapse. For this reason, a central tube structure needs to be inserted into the cell to support and protect the cell.

[0003] There are usually tab areas at both ends of the battery cell, and the tab areas are generally processed by a flattening process. However, the tab areas are easily inserted and torn after being flattened, causing a short circuit in the battery cell and ultimately causing damage to the battery cell. Utility Model Content

[0004] The present application provides a secondary battery central tube structure and a secondary battery to solve the problem that the tab area of ​​a battery cell is easily inserted and torn after being flattened, causing a short circuit in the battery cell and resulting in damage to the battery cell.

[0005] In a first aspect, the present application provides a secondary battery central tube structure for a secondary battery cell, comprising:

[0006] The tube body is suitable for passing through the central through hole of the battery core;

[0007] A pair of support parts are respectively sleeved on the opposite ends of the tube body, and the pair of support parts are suitable for being respectively installed on the opposite ends of the central through hole and fitting with the pole ear area of ​​the battery core.

[0008] In an optional embodiment, each of the support portions is installed in a non-tab area of ​​the battery cell, and an outer side surface of each of the support portions is in contact with the tab area.

[0009] In an optional embodiment, the support portion includes an inner ring and an outer ring, the inner ring and the outer ring are connected by a plurality of spokes, the inner ring is sleeved on the tube body, and the outer side surface of the outer ring fits with the inner side surface of the pole ear area.

[0010] In an optional embodiment, the distance between a pair of the support portions is L 1 , satisfying L 2 ≤L 1 ≤L 2 +2L 3 , where L 2 is the diaphragm width of the cell, L 3 is the height of the tab area of ​​the battery cell.

[0011] In an optional embodiment, at least one of the support portions is detachably mounted on the tube body.

[0012] In an optional embodiment, one of the support parts is integrally formed with the tube body, and the other support part is sleeved on the tube body by means of a thread or a buckle;

[0013] Alternatively, a pair of the supporting parts are respectively sleeved on opposite ends of the tube body by means of threads or snap-fits.

[0014] In an optional embodiment, the tube body is provided with an axial through hole, or the tube body is a solid structure.

[0015] In an optional embodiment, when the tube body is provided with an axial through hole, the side wall of the tube body is further provided with a plurality of third through holes communicating with the axial through hole.

[0016] In a second aspect, the present application also provides a secondary battery, comprising:

[0017] A battery cell, wherein a central through hole is axially provided, wherein the central through hole comprises a first through hole connected to each other and second through holes located at two ends of the first through hole, wherein the radius of the second through hole is greater than the radius of the first through hole, and the battery cell is further provided with a tab area at two opposite ends, wherein the second through hole forms a tab-free area;

[0018] In the above-mentioned secondary battery central tube structure, the tube body is inserted into the first through hole, and a pair of the supporting parts are respectively installed in a pair of the second through holes and fit with the tab area.

[0019] In an optional embodiment, the radius of the non-electrode area is R 1 ,satisfy Where R 2 is the radius of the battery cell.

[0020] The technical solution of this application has the following advantages:

[0021] 1. The tube body is passed through the first through hole of the secondary battery cell to serve as an internal support of the cell, release the internal tension of the cell, and improve the stability of the cell.

[0022] 2. A pair of support parts are respectively installed in a pair of second through holes, that is, installed in the non-electrode lug area and fit with the pole lug area, which can fill the second through holes, effectively support the pole lug area of ​​the battery cell, and prevent the pole lug area from being inserted or torn after being flattened, thereby further improving the stability and safety of the battery cell.

[0023] 3. Since the tube body is provided with an axial through hole, and the side wall is also provided with a plurality of third through holes connected with the axial through hole, a liquid retaining structure can be formed, which is beneficial to improving the service life of the battery cell.

[0024] 4. The secondary battery cell forms a tab-free area by opening the second through hole, and the electrolyte can quickly pass through the tab-free area to increase the electrolyte infiltration rate, shorten the infiltration time, and improve the production efficiency of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a structural schematic diagram of a central tube structure of a secondary battery according to an embodiment of the present application;

[0027] Figure 2 for Figure 1 A schematic diagram of the structure of the support portion;

[0028] Figure 3 is another structural schematic diagram of the central tube structure of a secondary battery according to an embodiment of the present application;

[0029] Figure 4 for Figure 3 A schematic diagram of the structure of the support portion;

[0030] Figure 5 This is another structural schematic diagram of the central tube structure of a secondary battery in an embodiment of the present application;

[0031] Figure 6 for Figure 5 A schematic diagram of the structure of the support portion;

[0032] Figure 7 : is a structural schematic diagram of a tube body of a secondary battery central tube structure according to an embodiment of the present application;

[0033] Figure 8 is a schematic diagram of a tab area of ​​a secondary battery in an embodiment of the present application;

[0034] Fig. 9 is a cross-sectional view of a secondary battery cell of an embodiment of the present application;

[0035] Fig.10 This is a diagram of the implementation method of the electrode die-cutting method of the secondary battery in the embodiment of the present application.

[0036] Description of reference numerals:

[0037] 1. Tube body; 101. Third through hole; 2. Support part; 201. Inner ring; 202. Outer ring; 203. Spoke; 3. Battery cell; 301. Center through hole; 3011. First through hole; 3012. Second through hole; 302. Tab area; 303. Diaphragm; 304. Diaphragm area. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0040] In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically limited. The reference to "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0042] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0043] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "length", "width", "thickness", "up", "down", "inside", "outside", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0044] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0045] The positive electrode sheet, negative electrode sheet and separator of the battery cell are generally wound in the same direction by a winding needle to form a battery cell. After the battery cell is completed, in order to achieve lossless forming, the full-ear flattening process is generally adopted, that is, the flattening head at different angles is used for bending and forming. However, the ear area is easy to be inserted and torn after being flattened, causing the battery cell to short-circuit and cause battery cell damage. The flattened ear area is dense and compact, which blocks the electrolyte from the two ends of the battery cell to the middle of the battery cell, and the infiltration effect is poor.

[0046] In addition, during the charge and discharge process of secondary batteries, the battery cells are prone to expand inward and collapse, which will also cause the gap between the electrodes to decrease, making it difficult for the electrolyte to infiltrate and reabsorb, resulting in insufficient infiltration inside the battery cells and even a lack of electrolyte. The ion path between the positive and negative electrodes is cut off, causing lithium precipitation, and ultimately reducing the performance of the secondary battery.

[0047] In order to solve the problems existing in the above-mentioned related technologies, according to the first aspect of the present application, as Figure 1 As shown, a secondary battery central tube structure is provided, which is used for a secondary battery cell 3, and mainly includes: a tube body 1 and a pair of support parts 2. The tube body 1 is suitable for passing through the central through hole 301 of the secondary battery cell 3. The pair of support parts 2 are respectively sleeved at the opposite ends of the tube body 1. The pair of support parts 2 are suitable for being respectively installed at the opposite ends of the central through hole 301 and fitting with the pole ear area 302 of the cell 3.

[0048] The tube body 1 provided in the embodiment of the present application is inserted into the central through hole 301 of the battery cell 3 to serve as the internal support of the battery cell 3, release the internal tension of the battery cell 3, prevent the battery cell 3 from expanding inward and collapsing, and improve the stability of the battery cell 3. In addition, a pair of support parts 2 are respectively installed at the opposite ends of the central through hole 301 and fit with the tab area 302, which can support the tab area 302 of the battery cell 3, prevent the tab area 302 from being flattened and then inserted or torn, reduce the occurrence of short circuit problems in the battery cell 3, and improve the stability and safety of the battery cell 3.

[0049] It should be noted that the embodiment of the present application does not limit the material of the tube body 1 and the support part 2. In order to reduce the use cost, the tube body 1 and the support part 2 can be made of the same material. For example, the tube body 1 and the support part 2 are both made of conventional solidified plastic materials such as polyurethane, polyethylene terephthalate (PET), and isocyanate.

[0050] In an optional embodiment, each support portion 2 is installed in the non-electrode lug area 302 of the battery cell 3 to ensure the integrity of the non-electrode lug area 302. The outer side of each support portion 2 fits the lug area 302, which can effectively support the lug area 302 of the battery cell 3, further improving the stability and safety of the battery cell 3.

[0051] Specifically, the central through hole 301 of the battery cell 3 includes a first through hole 3011 connected to each other and second through holes 3012 located at both ends of the first through hole 3011, the radius of the second through hole 3012 is greater than the radius of the first through hole 3011, and the opposite ends of the battery cell 3 are also provided with a pole ear area 302, and the second through hole 3012 forms a pole-free ear area 302. The tube body 1 is penetrated through the first through hole 3011, and a pair of support portions 2 are respectively installed in a pair of second through holes 3012, that is, installed in the pole-free ear area 302 of the battery cell 3.

[0052] In an optional embodiment, if Figure 2 As shown, the support part 2 is wheel-shaped, including an inner ring 201 and an outer ring 202. The inner ring 201 and the outer ring 202 are connected by a plurality of spokes 203, the inner ring 201 is sleeved on the tube body 1, and the outer side surface of the outer ring 202 is in contact with the inner side surface of the tab area 302.

[0053] Specifically, Figure 2 As shown, the angle between adjacent spokes 203 is θ, 30°≤θ≤120°, and the width of the spokes 203 is about 1 to 3 mm, so that the electrolyte can smoothly pass through the gaps between the spokes 203 to improve the electrolyte infiltration rate. For example, the angle between adjacent spokes 203 is 45 degrees, and the width of the spokes 203 is 2 mm.

[0054] In an optional embodiment, if Figure 1 and Figure 8 As shown, the distance between a pair of support parts 2 is L 1 , satisfying L 2 ≤L 1 ≤L 2 +2L 3 , where L 2 is the width of the diaphragm 303 of the battery cell 3, L 3 is the height of the tab area 302 of the battery cell 3. By limiting the above dimensions, it is possible to ensure that the outer side surface of the outer ring 202 of the support portion 2 fits at least partially with the inner side surface of the tab area 302, so as to support the tab area 302. Otherwise, the support portion 2 cannot contact the tab area 302, and the tab area 302 has no effective support, which makes it easy to be inserted and torn after being flattened, causing the battery cell 3 to short-circuit and damage the battery cell 3.

[0055] Since the tube body 1 needs to be inserted into the first through hole 3011 and the radius of the support portion 2 is larger than the radius of the tube body 1 , in order to avoid the support portion 2 hindering the tube body 1 from being inserted into the first through hole 3011 of the battery core 3 , at least one support portion 2 needs to be detachably mounted on the tube body 1 .

[0056] It should be noted that the embodiment of the present application does not limit the detachable connection method between the support part 2 and the tube body 1, and any existing structure can be selected as needed.

[0057] According to the embodiments of the present application, the detachable connection between the support portion 2 and the tube body 1 may be in various forms.

[0058] Form 1:

[0059] In an optional embodiment, if Figure 3 and Figure 4 As shown, one of the support parts 2 is integrally formed with the tube body 1, and the other support part 2 is sleeved on the tube body 1 through a thread. Specifically, one end of the tube body 1 is provided with an external thread, and the inner side of the inner ring 201 of one support part 2 is provided with an internal thread used in conjunction with the external thread of the tube body 1. The support part 2 and the tube body 1 are connected by threads, and the tightness is strong, which can prevent the support part 2 from being separated from the tube body 1.

[0060] Furthermore, in order to facilitate the welding of the battery cell 3, the connection between the tube body 1 and the support part 2 needs to be spaced a distance from the end face thereof. Specifically, the thread on the tube body 1 needs to be spaced about 2 to 4 mm from the end of the tube body 1, and the tube body 1 and the support part 2 are conveniently threadedly connected.

[0061] Form 2:

[0062] In an optional embodiment, if Figure 5 and Figure 6 As shown, one of the support parts 2 is integrally formed with the tube body 1, and the other support part 2 is mounted on the tube body 1 by a buckle, which facilitates the quick installation of the support part 2 and the tube body 1. Specifically, a card slot is provided at one end of the tube body 1, and the card slot does not affect the insertion of the tube body 1 into the battery cell 3, which is convenient for use. A card block is provided on the inner side of the inner ring 201 of the other support part 2 for use with the card slot, and the support part 2 and the tube body 1 are detachably connected by inserting the card block into the card slot.

[0063] It should be noted that the number of the card slots on the tube body 1 can be selected and set according to actual needs, and correspondingly, the card block of the support part 2 is adapted to the card slot. In this regard, the embodiment of the present application does not impose too many restrictions. For example, the card slots and buckles can correspond one to one, and four are set respectively.

[0064] Form three:

[0065] In an optional embodiment, a pair of support parts 2 are respectively arranged on opposite ends of the tube body 1 through threaded sleeves, that is, the pair of support parts 2 are both detachable, which can share the wear of the threads during disassembly and installation, and is beneficial to increasing the service life of the threads.

[0066] Form 4:

[0067] In an optional embodiment, a pair of support portions 2 are respectively mounted on opposite ends of the tube body 1 through buckles, which facilitates installation and helps reduce wear on the slots and buckles.

[0068] In an optional embodiment, the tube body 1 is provided with an axial through hole (not shown in the figure), that is, the tube body 1 is a tube with a wall thickness of about 2 to 4 mm, which is conducive to reducing the weight of the tube body 1.

[0069] Further, in an optional embodiment, as Figure 7 As shown, the side wall of the tube body 1 is also provided with a plurality of third through holes 101 communicating with the axial through hole, forming a liquid retaining structure to improve the life of the battery cell 3. Specifically, the plurality of third through holes 101 can be arranged regularly, such as forming an array, or can be arranged irregularly.

[0070] In an optional embodiment, the tube body 1 is a solid structure with higher structural strength and longer service life, which is conducive to effectively supporting the battery cell 3 in the long term.

[0071] In the second aspect, the present application also provides a secondary battery, mainly comprising: a battery cell 3 and a secondary battery central tube structure. The battery cell 3 is axially provided with a central through hole 301. The central through hole 301 includes a first through hole 3011 that is connected to each other and a second through hole 3012 located at both ends of the first through hole 3011. The radius of the second through hole 3012 is greater than the radius of the first through hole 3011, and the second through hole 3012 forms a non-polar ear area 302, and the outer side of the second through hole 3012 forms a polar ear area 302. The tube body 1 is penetrated through the first through hole 3011, and a pair of support parts 2 are respectively installed in a pair of second through holes 3012 and fit with the polar ear area 302.

[0072] The secondary battery provided in the embodiment of the present application has the same effect as the central tube structure of the secondary battery, that is, the tube body 1 is penetrated through the first through hole 3011 of the secondary battery cell 3 to serve as the internal support of the cell 3, release the internal tension of the cell 3, prevent the cell 3 from expanding inward and collapsing, and improve the stability of the cell 3. In addition, a pair of support parts 2 are respectively installed in a pair of second through holes 3012, and fit with the tab area 302, which can fill the second through holes 3012, support the tab area 302 of the cell 3, prevent the tab area 302 from being flattened and then inserted or torn, reduce the problem of short circuit in the cell 3, and improve the stability and safety of the cell 3.

[0073] In addition, compared with the traditional secondary battery structure with a full-electrode lug area, the secondary battery provided in the embodiment of the present application uses the second through hole 3012 to form the non-electrode lug area 302, and the electrolyte can pass through the non-electrode lug area 302, which shortens the infiltration time by about 2 hours, improves the infiltration efficiency by about 20%, saves energy consumption, and improves the production efficiency of the secondary battery.

[0074] Specifically, the central through hole 301 of the battery cell 3 is generally a diaphragm stirring hole or a hot hole. The battery cell 3 has a tab die-cutting process before winding. The second through hole 3012 is formed by cutting the inner ring tabs of the positive and negative pole pieces, that is, the tab-free area 302 is formed. The length of the die-cut tab is calculated according to the thickness of the pole piece and the number of windings through the Archimedean spiral. Fig.10 As shown, in order to prevent the tab die-cutting process from cutting into the diaphragm area 304 and affecting the yield rate of the battery cell 3 , part of the tab area 302 needs to be retained in the upper section of the diaphragm area 304 .

[0075] Specifically, the secondary battery may be a lithium-ion cylindrical battery.

[0076] In an optional embodiment, if Fig. 9 As shown, the radius R of the second through hole 3012 1 Greater than the radius R of the first through hole 3011 3 The radius R of the second through hole 3012 is 1 It can be regarded as the radius of the tab-free area 302 and also as the radius of the support portion 2 . Where R 2 is the radius of the battery cell 3. 1 Within the above range, the welding area and the tab-free area can be balanced, and the tab-free area 302 can be used to increase the electrolyte infiltration rate while ensuring the welding strength. If it is not within the above range, the welding area is too small to cause connection failure, or the flow of electrolyte is blocked, resulting in poor infiltration effect.

[0077] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection created by this application.

Claims

1. A secondary battery central tube structure, used for a secondary battery cell (3), characterized in that: include: A tube body (1) adapted to be inserted into a central through hole (301) of the battery core (3); A pair of support parts (2) are respectively sleeved on opposite ends of the tube body (1); the pair of support parts (2) are suitable for being respectively installed on opposite ends of the central through hole (301) and fitting with the tab area (302) of the battery cell (3).

2. The secondary battery central tube structure according to claim 1, characterized in that: Each of the support parts (2) is installed in a non-electrode lug area (302) of the battery cell (3), and the outer side surface of each of the support parts (2) is in contact with the electrode lug area (302).

3. The secondary battery central tube structure according to claim 2, characterized in that: The support portion (2) comprises an inner ring (201) and an outer ring (202), wherein the inner ring (201) and the outer ring (202) are connected via a plurality of spokes (203), the inner ring (201) is sleeved on the tube body (1), and the outer side surface of the outer ring (202) is in contact with the inner side surface of the pole lug region (302).

4. The secondary battery central tube structure according to claim 2, characterized in that: The distance between a pair of the support parts (2) is L1, satisfying L2≤L1≤L2+2L3, wherein L2 is the width of the diaphragm (303) of the battery cell (3), and L3 is the height of the tab region (302) of the battery cell (3).

5. The secondary battery central tube structure according to any one of claims 1 to 4, characterized in that: At least one of the support parts (2) is detachably sleeved on the tube body (1).

6. The secondary battery central tube structure according to claim 5, characterized in that: One of the support parts (2) is integrally formed with the tube body (1), and the other support part (2) is sleeved on the tube body (1) by means of a thread or a snap fit; Alternatively, a pair of the support portions (2) are respectively mounted on opposite ends of the tube body (1) by means of threads or snap-fits.

7. The secondary battery central tube structure according to any one of claims 1 to 4, characterized in that: The tube body (1) is provided with an axial through hole, or the tube body (1) is a solid structure.

8. The secondary battery central tube structure according to claim 7, characterized in that: When the tube body (1) is provided with an axial through hole, the side wall of the tube body (1) is also provided with a plurality of third through holes (101) which are in communication with the axial through hole.

9. A secondary battery, characterized in that: include: A battery cell (3) is provided with a central through hole (301) in an axial direction, wherein the central through hole (301) comprises a first through hole (3011) that is connected to each other and second through holes (3012) located at two ends of the first through hole (3011), wherein the radius of the second through hole (3012) is greater than the radius of the first through hole (3011), and the battery cell (3) is further provided with a pole ear region (302) at two opposite ends, wherein the second through hole (3012) forms a pole ear-free region (302); The secondary battery central tube structure according to any one of claims 1 to 8, wherein the tube body (1) is passed through the first through hole (3011), and a pair of the support portions (2) are respectively installed in a pair of the second through holes (3012) and fit with the pole ear area (302).

10. The secondary battery according to claim 9, characterized in that: The radius of the non-electrode area (302) is R1, satisfying Wherein R2 is the radius of the battery core (3).

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