Cover plate assembly and secondary battery

Abstract

The utility model discloses a cover plate assembly and a secondary battery, and belongs to the technical field of batteries, the cover plate assembly comprises a plate body, a pole, a connecting sheet and a sealing member, the plate body has a first direction and a second direction which intersect with each other; the pole penetrates through the plate body; the connecting piece comprises a first part, a bent part and a second part, the bent part is connected to one end of the first part along the second direction, and the second part is connected to one end of the bent part far away from the first part; the first part is arranged on one side of the plate body along the first direction, and the first part is sleeved with the pole; when the bending part is bent, the second part extends along the first direction; part of the sealing piece is arranged between the plate body and the first part in the first direction and connected with the plate body and the first part. According to the invention, the first part of the connecting piece is connected with the plate body to replace a welding block, and meanwhile, the second part can rotate relative to the first part by arranging the bending part, so that the tab can be connected between the second part and the plate body, and the space utilization rate of the accommodating cavity is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a cover plate assembly and a secondary battery. BACKGROUND

[0002] The pole column and the welding block of the secondary battery are connected to clamp the plate body between the part of the pole column and the welding block, so that the plate body limits the pole column in the extension direction of the pole column hole, and the displacement of the pole column is avoided. Moreover, the welding block is used for connecting the connecting sheet, and the pole lug is drawn out from the body and connected to the connecting sheet after being bent.

[0003] However, the welding block and the pole lug connected to the connecting sheet occupy a certain space, so that the space utilization rate in the secondary battery is low. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing a cover plate assembly to solve the technical problem of low space utilization rate in the secondary battery, and another object of the application is to provide a secondary battery.

[0005] Technical scheme, the application provides a cover plate assembly, which comprises:

[0006] A plate body, the plate body has a first direction and a second direction intersecting with each other;

[0007] A pole column, the pole column is arranged in the plate body;

[0008] A connecting sheet, the connecting sheet comprises a first part, a bent part and a second part, the bent part is connected to one end of the first part along the second direction, and the second part is connected to one end of the bent part away from the first part; the first part is arranged on one side of the plate body along the first direction, and the pole column is arranged in the first part; when the bent part is bent, the second part extends along the first direction;

[0009] A sealing element, part of the sealing element is arranged between the plate body and the first part along the first direction, and the plate body and the first part are connected respectively.

[0010] In some embodiments, the connecting sheet further comprises a transition part, the transition part is connected to one side of the first part away from the plate body, and the bent part is connected between the transition part and the second part.

[0011] In some embodiments, the bent part has a through hole, and the through hole penetrates through the bent part.

[0012] In some embodiments, the pole post comprises a main body portion and a first limiting portion, the main body portion is arranged in the plate body, the first limiting portion is connected to the main body portion along the second direction, the first portion is sleeved with the main body portion, at least part of the first portion is arranged between the first limiting portion and the plate body, and is connected with the first limiting portion.

[0013] In some embodiments, the first portion has a mounting hole, and the first limiting portion is arranged in the mounting hole.

[0014] In some embodiments, the first portion further comprises a protrusion, the protrusion is arranged between the hole wall of the mounting hole and the first limiting portion, and is connected with the hole wall of the mounting hole and the first limiting portion respectively, and the protrusion forms a stepped structure.

[0015] In some embodiments, the pole post further comprises a second limiting portion, the second limiting portion is connected to the main body portion along the second direction, the first limiting portion and the second limiting portion are arranged at intervals along the first direction, and the plate body is arranged between the first portion and the second limiting portion; the cover plate assembly further comprises an insulating member, at least part of the insulating member is arranged between the second limiting portion and the plate body along the first direction, and is connected with the second limiting portion and the plate body respectively.

[0016] In some embodiments, the plate body has a pole post hole; the pole post further comprises a protruding portion, the protruding portion is connected to the main body portion along the second direction, the protruding portion is connected to one side of the second limiting portion close to the first limiting portion, and part of the protruding portion is arranged in the pole post hole; part of the sealing member is arranged between the protruding portion and the first portion along the first direction, and is connected with the protruding portion and the first portion respectively.

[0017] In some embodiments, the sealing member comprises:

[0018] a first sealing portion, the first sealing portion is arranged in the pole post hole, and the first sealing portion is arranged between the plate body and the protruding portion, and is connected with the plate body and the protruding portion respectively;

[0019] a second sealing portion, the second sealing portion is connected to one side of the first sealing portion along the first direction towards the first portion, part of the second sealing portion is arranged between the plate body and the first portion along the first direction, and is connected with the plate body and the first portion respectively; part of the second sealing portion is arranged between the protruding portion and the first portion along the first direction, and is connected with the protruding portion and the first portion respectively.

[0020] Correspondingly, the application also provides a secondary battery comprising the cover plate assembly as described in any one of the above embodiments.

[0021] Beneficial effects: compared with the prior art, the cover plate assembly provided by the embodiment of the application comprises a plate body, a pole, a connecting piece and a sealing piece, the plate body has a first direction and a second direction intersecting with each other, the pole is arranged in the plate body, the connecting piece comprises a first part, a bent part and a second part, the bent part is connected to one end of the first part along the second direction, and the second part is connected to one end of the bent part away from the first part, the first part is arranged on one side of the plate body along the first direction, and the first part is sleeved with the pole, when the bent part is bent, the second part extends along the first direction, and part of the sealing piece is arranged between the plate body and the first part along the first direction and connected to the plate body and the first part respectively. The first part of the connecting piece is connected to the plate body to replace the welding block, and meanwhile, the bent part is arranged to enable the second part to rotate relative to the first part, so that the pole lug can be connected between the second part and the plate body, thereby improving the space utilization of the accommodating cavity. BRIEF DESCRIPTION OF DRAWINGS

[0022] The technical solutions and other beneficial effects of the application will be apparent through the following detailed description of the specific embodiments of the application in combination with the drawings.

[0023] Figure 1 A structural schematic diagram of the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0024] Figure 2 A structural schematic diagram of the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0025] Figure 3 A structural schematic diagram of the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0026] Figure 4 A sectional view of the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0027] Figure 5 A structural schematic diagram of the cover plate assembly provided by the embodiment of the application is shown in the figure; Figure 4 A detailed view of circle A in the figure;

[0028] Figure 6 A sectional view of the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0029] Figure 7 A detailed view of circle B in the figure; Figure 6 A detailed view of circle B in the figure;

[0030] Figure 8 A structural schematic diagram of the connecting piece in the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0031] Figure 9 A structural schematic diagram of the connecting piece in the cover plate assembly provided by the embodiment of the application is shown in the figure;

[0032] Figure 10 An assembly view of a secondary battery according to another embodiment of the present application;

[0033] Figure 11 A sectional view of a secondary battery according to another embodiment of the present application.

[0034] Reference numerals, 100 - plate body, 110 - pole post hole, 200 - pole post, 210 - main body part, 220 - first limiting part, 230 - second limiting part, 240 - protruding part, 300 - connecting piece, 310 - first part, 311 - mounting hole, 312 - first accommodating groove, 313 - protrusion, 320 - bent part, 321 - through hole, 330 - second part, 340 - transition part, 400 - sealing member, 410 - first sealing part, 420 - second sealing part, 500 - insulating member, 600 - electrode assembly, 610 - tab, 620 - body. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0036] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, 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. In the description of the present application, the meaning of "multiple" is two or more than two, unless otherwise explicitly specified and limited. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features.

[0037] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0038] The pole 200 of the secondary battery is connected with the welding block to clamp the plate body 100 between the part of the pole 200 and the welding block, so that the plate body 100 limits the displacement of the pole 200 in the extension direction of the pole hole 110, avoiding the displacement of the pole 200. Moreover, the welding block is used to connect the connecting sheet 300, and the tab 610 is led out from the body 620 and connected to the connecting sheet 300 after being bent.

[0039] However, the welding block and the tab 610 connected to the connecting sheet 300 occupy a certain space, so that the space utilization rate inside the secondary battery is low.

[0040] In order to solve the above technical problem of low space utilization rate inside the secondary battery, the first embodiment of the present application provides a cover plate assembly, please refer to Figure 1 、 Figure 2 and Figure 3 The cover plate assembly comprises a plate body 100, a pole 200, a connecting sheet 300 and a sealing member 400, the plate body 100 has a first direction X and a second direction Y intersecting with each other; the pole 200 is arranged through the plate body 100; the connecting sheet 300 comprises a first part 310, a bent part 320 and a second part 330, the bent part 320 is connected to one end of the first part 310 along the second direction Y, and the second part 330 is connected to one end of the bent part 320 away from the first part 310; the first part 310 is arranged on one side of the plate body 100 along the first direction X, and the pole 200 is arranged through the first part 310; when the bent part 320 is bent, the second part 330 extends along the first direction X; part of the sealing member 400 is arranged between the plate body 100 and the first part 310 along the first direction X, and is connected to the plate body 100 and the first part 310 respectively.

[0041] Among them, the first direction X is the direction of the arrow X, and the second direction Y is the direction of the arrow Y.

[0042] Specifically, when the bent part 320 is flattened, the second part 330 is arranged opposite to the plate body 100 along the first direction X, and the first part 310 and the second part 330 are respectively located on both sides of the bent part 320 along the second direction Y.

[0043] In some embodiments, part of the pole 200 is arranged on one side of the plate body 100 away from the first part 310 along the first direction X, and the plate body 100 is clamped between the part of the pole 200 and the first part 310 along the first direction X, that is, the first part 310 not only plays a role of connecting the tab 610, but also plays a role of clamping the plate body 100, which can replace the welding block.

[0044] In some embodiments, the cover plate assembly further comprises an insulating member 500, at least part of the insulating member 500 is arranged between the plate body 100 and the part of the pole 200 along the first direction X, and insulatingly connects the part of the pole 200 and the plate body 100.

[0045] In some embodiments, the sealing member 400 is made of an insulating material, and the sealing member 400 can also serve as an insulating layer for the first portion 310 and the plate body 100.

[0046] In some embodiments, referring to Figure 3 , Figure 6 , Figure 9 and Figure 10 , the first portion 310 extends along the second direction Y, and the second portion 330 has a connecting surface. During assembly of the secondary battery, the bending portion 320 is bent so that the second portion 330 can extend along the first direction X, and the connecting surface is perpendicular to the second direction Y. Since there is more space for operation on the second connecting surface, the tab 610 can be connected to the connecting surface along the second direction Y.

[0047] In the above embodiments, the connecting sheet 300 is provided to clamp the plate body 100 to the pole 200, instead of the welding block, so that the types of parts of the cover plate assembly are reduced, the size of the cover plate assembly along the first direction X is reduced, and the structure of the cover plate assembly is more compact. At the same time, since the connecting sheet 300 has the bending portion 320 that can be bent, the difficulty of connecting the tab 610 between the second portion 330 and the plate body 100 is also reduced.

[0048] In some embodiments, referring to Figure 4 , Figure 5 and Figure 7 , the connecting sheet 300 further includes a transition portion 340 connected to the side of the first portion 310 away from the plate body 100, and the bending portion 320 is connected between the transition portion 340 and the second portion 330.

[0049] In the above embodiments, the transition portion 340 is provided to increase the maximum size between the second portion 330 and the first portion 310 along the first direction X, and to increase the distance between the second portion 330 and the plate body 100 along the first direction X, so as to provide more space for the tab 610 after the bending portion 320 is flattened. At the same time, the provision of the transition portion 340 can also avoid the bending portion 320 from causing the first portion 310 to warp or tilt when bent, thereby improving the reliability of the cover plate assembly.

[0050] In some embodiments, referring to Figure 5 , Figure 7 , Figure 8 and Figure 9 , the bending portion 320 has a through hole 321 that penetrates the bending portion 320.

[0051] In some embodiments, the bending portion 320 has a plurality of through holes 321, and the plurality of through holes 321 are spaced apart along a third direction. The first direction X, the second direction Y, and the third direction intersect.

[0052] In some embodiments, the plurality of through holes 321 are partially circular holes.

[0053] In the above embodiments, by setting the through holes 321 so that the bending portion 320 is a weak portion, when the second portion 330 is turned, the bending portion 320 is bent, avoiding the first portion 310 or the second portion 330 being bent when the second portion 330 is turned, thereby avoiding the first portion 310 or the second portion 330 being warped or tilted, and further improving the reliability of the connecting piece 300.

[0054] In some embodiments, referring to Figure 5 and Figure 7 , the pole 200 includes a main body portion 210 and a first limiting portion 220, the main body portion 210 is arranged through the plate body 100, the first limiting portion 220 is connected to the main body portion 210 along the second direction Y, the first portion 310 is sleeved with the main body portion 210, and at least part of the first portion 310 is arranged between the first limiting portion 220 and the plate body 100 and connected with the first limiting portion 220.

[0055] In some embodiments, the first limiting portion 220 is annularly arranged on the main body portion 210.

[0056] In some embodiments, the first limiting portion 220 is integrally formed with the main body portion 210.

[0057] In some embodiments, the main body portion 210 has a blind hole, and the first limiting portion 220 is formed by outwardly folding a portion of the main body portion 210 surrounding the blind hole.

[0058] In the above embodiments, by setting the first limiting portion 220 to limit the movement of the connecting piece 300 along the first direction X, the movement of the connecting piece 300 away from the plate body 100 along the first direction X is avoided.

[0059] It can be understood that when connecting the pole 200 and the connecting piece 300, the first portion 310 needs to be sleeved on the pole 200 first, and then welded. In the above embodiments, by setting the first limiting portion 220 which can have a certain positioning effect on the connecting piece 300 to reduce the difficulty of welding the pole 200 and the connecting piece 300, the assembly difficulty of the cover plate assembly is reduced.

[0060] In some embodiments, the first portion 310 has a mounting hole 311, and the first limiting portion 220 is arranged in the mounting hole 311.

[0061] In the above embodiments, by arranging the first limiting portion 220 in the mounting hole 311, the first limiting portion 220 is avoided from being exposed to the first portion 310, thereby occupying the space of the accommodation cavity in the secondary battery.

[0062] In some embodiments, the plate body 100 has a first surface and a second surface facing away from each other along the first direction X, and the first limiting portion 220 has a limiting surface which is a tapered surface, and an included angle between the limiting surface and the first surface is an acute angle.

[0063] In some embodiments, the mounting hole 311 has a hole wall capable of abutting against the limiting surface.

[0064] In the above embodiments, by arranging the limiting surface and the hole wall capable of abutting against the limiting surface, the connecting piece 300 can be automatically centered after being sleeved on the pole 200, and the difficulty of welding the pole 200 and the connecting piece 300 is further reduced, thereby reducing the assembly difficulty of the cover plate assembly.

[0065] In some embodiments, referring to Figure 5 and Figure 7 the first portion 310 further includes a protrusion 313 arranged between the hole wall of the mounting hole 311 and the first limiting portion 220 and connecting the hole wall of the mounting hole 311 and the first limiting portion 220, respectively, and the protrusion 313 forms a stepped structure.

[0066] Specifically, the stepped structure includes a surface of the protrusion 313 facing away from the plate body 100 along the first direction X and a surface of the protrusion 313 facing the first limiting portion 220 along a direction perpendicular to the first direction X.

[0067] Specifically, the first portion 310 has a first accommodating groove 312 on a side thereof facing away from the plate body 100 along the first direction X, the first accommodating groove 312 is surrounded by the stepped structure formed by the protrusion 313 and the hole wall of the mounting hole 311, the first accommodating groove 312 is arranged around the mounting hole 311, and the first accommodating groove 312 is in communication with the mounting hole 311.

[0068] In some embodiments, the protrusion 313 is arranged around the first limiting portion 220 along a circumferential direction of the first limiting portion 220.

[0069] It can be understood that when the first limiting portion 220 and the first portion 310 are welded, a weld reinforcement may be generated. In the above embodiments, by arranging the first accommodating groove 312 to accommodate the weld reinforcement, the weld reinforcement can be prevented from being exposed to the connecting piece 300, thereby preventing the weld reinforcement from contacting other components and causing a short circuit, and the reliability of the cover plate assembly is improved.

[0070] In some embodiments, referring to Figure 5 and Figure 7The pole 200 further comprises a second limiting portion 230 connected to the main body portion 210 along the second direction Y, the first limiting portion 220 and the second limiting portion 230 are arranged apart along the first direction X, and the plate body 100 is arranged between the first portion 310 and the second limiting portion 230; the cover plate assembly further comprises an insulating member 500, at least part of the insulating member 500 is arranged between the second limiting portion 230 and the plate body 100 along the first direction X and is connected to the second limiting portion 230 and the plate body 100 respectively.

[0071] In some embodiments, the second limiting portion 230 is arranged around the main body portion 210.

[0072] In some embodiments, the insulating member 500 is arranged between the second limiting portion 230 and the plate body 100 along the first direction X. In other embodiments, part of the insulating member 500 is arranged between the second limiting portion 230 and the plate body 100 along the first direction X and is connected to the second limiting portion 230 and the plate body 100 respectively to insulate the second limiting portion 230 and the plate body 100; and part of the insulating member 500 is arranged around the second limiting portion 230 to avoid short circuit caused by contact between the pole 200 and other components.

[0073] In the above embodiments, the second limiting portion 230 is arranged to enable the pole 200 to clamp the plate body 100 with the connecting sheet 300 along the first direction X, so that the connecting sheet 300 can function as a welding block, thereby making the structure of the cover plate assembly more compact and the space utilization inside the secondary battery using the cover plate assembly higher.

[0074] In some embodiments, referring to Figure 5 and Figure 7 the plate body 100 has a pole hole 110; the pole 200 further comprises a protruding portion 240 connected to the main body portion 210 along the second direction Y, the protruding portion 240 is connected to one side of the second limiting portion 230 close to the first limiting portion 220, part of the protruding portion 240 is arranged in the pole hole 110; and part of the sealing member 400 is arranged between the protruding portion 240 and the first portion 310 along the first direction X and is connected to the protruding portion 240 and the first portion 310 respectively.

[0075] In some embodiments, the protruding portion 240 is arranged around the main body portion 210.

[0076] In the above embodiment, the convex portion 240 is arranged to increase the size of the pole post 200 along the second direction Y, thereby increasing the degree of elastic deformation of the portion of the sealing member 400 along the second direction Y, and improving the sealing performance of the sealing member 400. Meanwhile, the portion of the sealing member 400 can be clamped between the convex portion 240 and the first portion 310 along the first direction X, that is, the convex portion 240 also cooperates with the sealing member 400 to extend the sealing path of the sealing member 400, thereby improving the sealing effect of the sealing member 400, and further improving the reliability of the cover plate assembly. Meanwhile, the sealing member 400 can indirectly connect the convex portion 240 and the first portion 310, and when the first portion 310 is sleeved on the pole post 200, the indirectly connected convex portion 240 can avoid the inclination of the first portion 310, thereby playing a positioning role on the connecting sheet 300, reducing the welding difficulty of the connecting sheet 300 and the pole post 200, and thereby reducing the assembly difficulty of the cover plate assembly.

[0077] In some embodiments, referring to Figure 5 and Figure 7 , the sealing member 400 comprises a first sealing portion 410 and a second sealing portion 420, the first sealing portion 410 is arranged to pass through the pole post hole 110, and the first sealing portion 410 is arranged between the plate body 100 and the convex portion 240 and connected to the plate body 100 and the convex portion 240, respectively; the second sealing portion 420 is connected to one side of the first sealing portion 410 along the first direction X and towards the first portion 310, and a portion of the second sealing portion 420 is arranged between the plate body 100 and the first portion 310 along the first direction X and connected to the plate body 100 and the first portion 310, respectively; a portion of the second sealing portion 420 is arranged between the convex portion 240 and the first portion 310 along the first direction X and connected to the convex portion 240 and the first portion 310, respectively.

[0078] In some embodiments, the first sealing portion 410 is arranged to surround the convex portion 240, and the second sealing portion 420 is arranged to surround the main body portion 210.

[0079] In the above embodiment, the first sealing portion 410 is arranged to seal the connection between the convex portion 240 and the plate body 100, and the second sealing portion 420 is arranged to seal the connection between the plate body 100 and the first portion 310, thereby improving the sealing performance of the cover plate assembly and improving the reliability of the cover plate assembly. Meanwhile, the arrangement of the second sealing portion 420 between the convex portion 240 and the first portion 310 also indirectly connects the convex portion 240 and the connecting sheet 300, thereby avoiding the inclination of the connecting sheet 300 when it is sleeved on the pole post 200, and playing a certain positioning role.

[0080] Correspondingly, the application also provides a secondary battery comprising the cover plate assembly according to any one of the above embodiments.

[0081] In some embodiments, referring to Figure 10 andFigure 11 The secondary battery further includes a shell having a receiving cavity and an electrode assembly 600 disposed in the receiving cavity, and the electrode assembly 600 includes a body 620 and a tab 610 connected to the body 620, and a portion of the tab 610 is connected to the side of the second part 330 facing the plate body 100 in the first direction X.

[0082] In the above embodiment, the tab 610 is connected to the side of the second part 330 facing the plate body 100 after being bent, avoiding the space occupied by the bending of the tab 610 when it is connected to the side of the connecting piece 300 away from the plate body 100 in the receiving cavity, thereby improving the space utilization of the secondary battery.

[0083] The above describes in detail a cover plate assembly and a secondary battery provided by the embodiments of the present application. The principles and implementation manners of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the technical solutions of the present application and the core ideas thereof. Those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some technical features can be replaced equivalently, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A cover assembly, characterized by The application relates to a cover plate assembly. The cover plate assembly comprises: a plate body having a first direction and a second direction intersecting with each other; a pole column penetrating the plate body; a connecting sheet comprising a first part, a bent part and a second part, the bent part being connected to one end of the first part along the second direction, the second part being connected to one end of the bent part away from the first part, the first part being arranged on one side of the plate body along the first direction, the pole column penetrating the first part, the second part extending along the first direction when the bent part is bent; 2. The cover plate assembly of claim 1, wherein, a seal part, part of the seal part being arranged between the plate body and the first part along the first direction and connecting the plate body and the first part respectively.

3. The cover plate assembly of claim 2, wherein, The connecting sheet further comprises a transition part, the transition part being connected to one side of the first part away from the plate body, the bent part being connected between the transition part and the second part.

4. The cover plate assembly of claim 1, wherein, The bent part has a through hole penetrating the bent part.

5. The cover plate assembly of claim 4, wherein, The pole column comprises a main body part and a first limiting part, the main body part penetrating the plate body, the first limiting part being connected to the main body part along the second direction, the first part being sleeved with the main body part, at least part of the first part being arranged between the first limiting part and the plate body and connected with the first limiting part.

6. The cover plate assembly of claim 5, wherein, The first part has a mounting hole, the first limiting part being arranged in the mounting hole.

7. The cover plate assembly of claim 4, wherein, The first part further comprises a protrusion, the protrusion being arranged between the hole wall of the mounting hole and the first limiting part and connecting the hole wall of the mounting hole and the first limiting part respectively, the protrusion forming a stepped structure.

8. The cover plate assembly of claim 7, wherein, The pole column further comprises a second limiting part, the second limiting part being connected to the main body part along the second direction, the first limiting part and the second limiting part being arranged at intervals along the first direction, the plate body being arranged between the first part and the second limiting part; the cover plate assembly further comprises an insulating part, at least part of the insulating part being arranged between the second limiting part and the plate body along the first direction and connecting the second limiting part and the plate body respectively.

9. The cover plate assembly of claim 8, wherein, The plate body has a pole column hole; the pole column further comprises a protruding part, the protruding part being connected to the main body part along the second direction, the protruding part being connected to one side of the second limiting part close to the first limiting part, part of the protruding part penetrating the pole column hole; part of the seal part is arranged between the protruding part and the first part along the first direction and connecting the protruding part and the first part respectively. The seal part comprises: a first seal part, the first seal part penetrating the pole column hole, the first seal part being arranged between the plate body and the protruding part and connecting the plate body and the protruding part respectively. A second sealing portion is connected to the first sealing portion on the side of the first portion in the first direction, and a part of the second sealing portion is arranged between the plate body and the first portion in the first direction and connected to the plate body and the first portion, respectively; and a part of the second sealing portion is arranged between the protruding portion and the first portion in the first direction and connected to the protruding portion and the first portion, respectively.

10. A secondary battery characterized by comprising: A cover plate assembly as claimed in any one of claims 1-9.

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