Secondary battery and battery pack

Abstract

The utility model discloses a secondary battery and a battery pack, and belongs to the technical field of batteries, the secondary battery comprises a shell, an electrode assembly and a cover plate assembly, the shell is provided with an accommodating cavity; the electrode assembly is arranged in the accommodating cavity and comprises a body and a tab connected to the body; the cover plate assembly comprises a plate body, a connecting sheet and a pole, the plate body is provided with a pole hole, and the plate body is connected with the shell and covers the accommodating cavity; the connecting sheet is arranged in the accommodating cavity and connected with the plate body, and the connecting sheet is connected with the tab; the pole comprises a main body part and a first limiting part, and the main body part penetrates through the pole hole; the first limiting part surrounds the body part and is connected with the body part. The connecting piece is connected to the side, close to the plate body, of the first limiting part. According to the secondary battery, the connecting piece connected with the pole can be connected with the plate body from the side of the accommodating cavity, so that the connecting piece has the function of an original welding block, the types of parts of the secondary battery are reduced, the assembly steps of the secondary battery are reduced, and the assembly difficulty of the secondary battery is reduced.

Description

TECHNICAL FIELD

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

[0002] The pole post and the welding block are connected to clamp the plate body between the part of the pole post and the welding block, so that the plate body limits the pole post in the extension direction of the pole post hole, and the pole post is prevented from being displaced.

[0003] In the assembly process of the secondary battery, the part of the pole post needs to be inserted into the pole post hole, the welding block is welded to the pole post, and then the connecting piece is welded to the welding block to complete the assembly of the pole post part. The assembly process has multiple welding steps, and the assembly of the secondary battery is relatively complex. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims to provide a secondary battery to solve the technical problem that the assembly process of the secondary battery is relatively complex, and another object of the application is to provide a battery pack.

[0005] Technical scheme, the application provides a secondary battery, which comprises:

[0006] A shell, the shell has a containing cavity;

[0007] An electrode assembly, the electrode assembly is arranged in the containing cavity, and the electrode assembly comprises a body and a tab connected to the body;

[0008] A cover plate assembly, the cover plate assembly comprises a plate body, a connecting piece and a pole post, the plate body has a pole post hole, the plate body is connected with the shell and covers the containing cavity; the connecting piece is arranged in the containing cavity and connected with the plate body, and the connecting piece is connected with the tab; the pole post comprises a main body part and a first limiting part, the main body part is inserted into the pole post hole; the first limiting part surrounds the main body part and is connected with the main body part in a direction perpendicular to the thickness direction of the plate body, and the connecting piece is connected to one side of the first limiting part close to the plate body.

[0009] In some embodiments, in the direction perpendicular to the thickness direction of the plate body, the first limiting part has a maximum size L1, which satisfies: 0.5mm≤L1≤1.2mm.

[0010] In some embodiments, the cover plate assembly further comprises a sealing member, and the sealing member comprises:

[0011] A first part, the first part is inserted into the pole post hole, and the first part is arranged between the pole post and the plate body in a direction perpendicular to the thickness direction of the plate body and is connected with the pole post and the plate body respectively;

[0012] A second portion is connected to the first portion near one side of the connecting piece, and a part of the second portion is arranged between the plate body and the connecting piece and connected to the plate body and the connecting piece respectively.

[0013] In some embodiments, the pole post further comprises:

[0014] A second limiting portion is arranged on one side of the plate body away from the electrode assembly, surrounds the main body portion, and is connected to the main body portion in a direction perpendicular to the thickness direction of the plate body, and the plate body is clamped between the second limiting portion and the connecting piece.

[0015] A protruding portion surrounds the main body portion and is connected to the main body portion in a direction perpendicular to the thickness direction of the plate body, and the protruding portion has a first sealing surface and a second sealing surface connected to each other, the first sealing surface is connected to the first portion, and the second sealing surface faces the connecting piece; a part of the second portion is arranged between the connecting piece and the second sealing surface and connected to the connecting piece and the second sealing surface respectively.

[0016] In some embodiments, in the direction perpendicular to the thickness direction of the plate body, the second sealing surface has a minimum size L2, which satisfies: L2≥0.8mm.

[0017] In some embodiments, the connecting piece comprises:

[0018] An extrusion portion has a mounting hole, the first limiting portion passes through the mounting hole and is connected to the extrusion portion, the second portion is connected to the extrusion portion, the extrusion portion has a first surface, and the first surface faces the electrode assembly.

[0019] A connecting portion is connected to the extrusion portion in a direction perpendicular to the thickness direction of the plate body, surrounds the extrusion portion, has a second surface, and the tab is connected to the second surface, the second surface faces the electrode assembly, and the first surface and the second surface are flush.

[0020] In some embodiments, in the thickness direction of the plate body, the extrusion portion has a maximum size H, and the connecting portion has a maximum size H3, which satisfies: H>H3.

[0021] In some embodiments, in the thickness direction of the plate body, the extrusion portion has a maximum distance H, which satisfies: 1.2mm≤H≤2.5mm; and / or,

[0022] The mounting hole has a first hole wall and a second hole wall connected to each other, the first hole wall is connected to the main body part, and the second hole wall is connected to the first limiting part; along the thickness direction of the plate body, the first hole wall has a maximum size H1, and H1≥0.2 mm is satisfied; and / or,

[0023] Along the thickness direction of the plate body, the connecting part has a maximum size H3, and 0.3 mm≤H3≤1.5 mm is satisfied; and / or,

[0024] Along the direction perpendicular to the thickness direction of the plate body, the extrusion part has a minimum size L3, and the second part has a minimum size L4, and L3-L4≥0.5 mm is satisfied.

[0025] In some embodiments, the extrusion part further has a first accommodating groove penetrating through the first surface, the first accommodating groove is arranged around the mounting hole, and the first accommodating groove is in communication with the mounting hole.

[0026] In some embodiments, along the thickness direction of the plate body, the first accommodating groove has a maximum size H2, and H2≥0.15 mm is satisfied.

[0027] Correspondingly, the application also provides a battery pack comprising the secondary battery according to any one of the above embodiments.

[0028] Advantages: compared with the prior art, the secondary battery provided by the embodiments of the application comprises a shell, an electrode assembly and a cover plate assembly, the shell has a receiving cavity; the electrode assembly is arranged in the receiving cavity, and the electrode assembly comprises a body and a tab connected to the body; the cover plate assembly comprises a plate body, a connecting piece and a pole, the plate body has a pole hole, the plate body is connected to the shell and covers the receiving cavity; the connecting piece is arranged in the receiving cavity and connected to the plate body, and the connecting piece is connected to the tab; the pole comprises a main body part and a first limiting part, the main body part penetrates the pole hole; the first limiting part surrounds the main body part and is connected to the main body part, and the connecting piece is connected to the first limiting part close to the plate body. In the application, the connecting piece connected to the pole is connected to the plate body from the side of the receiving cavity, so that the connecting piece has the function of the original welding block, thereby the welding block can be omitted from the cover plate assembly, the types of parts of the secondary battery are reduced, the assembly steps of the secondary battery are reduced, and the assembly difficulty of the secondary battery is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] The technical solutions and other advantages of the application will be apparent from the following detailed description of the specific embodiments of the application, combined with the accompanying drawings.

[0030] Figure 1 The structure schematic diagram of the secondary battery provided by the embodiments of the application is shown in the drawings;

[0031] Figure 2 A top view of a secondary battery provided in an embodiment of this application;

[0032] Figure 3 for Figure 2 Sectional view at point AA;

[0033] Figure 4 for Figure 3 Detailed view of section C in the middle frame;

[0034] Figure 5 for Figure 2 Sectional view at point BB;

[0035] Figure 6 for Figure 3 Detailed view of point D in the middle circle;

[0036] Figure 7 for Figure 3 Another detailed view of point D in the middle circle;

[0037] Figure 8 This is a schematic diagram of the structure of the connecting piece in the secondary battery provided in the embodiments of this application;

[0038] Figure 9 This is a schematic diagram of the connecting piece in a secondary battery from another angle, provided in an embodiment of this application.

[0039] Figure 10 for Figure 9 Detailed view of point E in the middle circle.

[0040] Reference numerals in the attached drawings: 100-housing shell, 110-receiving cavity, 200-electrode assembly, 210-body, 220-electrode tab, 300-cover plate assembly, 310-plate, 311-electrode post hole, 312-second receiving groove, 320-connecting piece, 321-extrusion part, 3211-mounting hole, 3212-first hole wall, 3213-second hole wall, 3214-first surface, 3215-first receiving groove, 322-connecting part, 3221-second surface, 330-electrode post, 331-body part, 332-first limiting part, 3321-connecting surface, 333-second limiting part, 334-protrusion, 3341-first sealing surface, 3342-second sealing surface, 340-sealing element, 341-first part, 342-second part. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0042] 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, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. 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 be explicitly or implicitly included one or more features.

[0043] 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 arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0044] The pole 330 of the secondary battery is connected with the welding block to clamp the plate body 310 between the part of the pole 330 and the welding block, so as to realize the limiting of the plate body 310 to the pole 330 in the extension direction of the pole hole 311, and avoid the displacement of the pole 330.

[0045] In the assembly process of the secondary battery, the part of the pole 330 needs to pass through the pole hole 311 first, and then the welding block is welded to the pole 330, and then the connecting sheet 320 is welded to the welding block to complete the assembly of the part of the pole 330. There are multiple welding steps in the assembly process, and the assembly of the pole 330 is more complex.

[0046] The pole 330 of the secondary battery is connected with the welding block to clamp the plate body 310 between the part of the pole 330 and the welding block, so as to realize the limiting of the plate body 310 to the pole 330 in the extension direction of the pole hole 311, and avoid the displacement of the pole 330.

[0047] In the assembly process of the secondary battery, the part of the pole 330 needs to pass through the pole hole 311 first, and then the welding block is welded to the pole 330, and then the connecting sheet 320 is welded to the welding block to complete the assembly of the part of the pole 330. There are multiple welding steps in the assembly process, and the assembly of the secondary battery is more complex.

[0048] In order to solve the above technical problems that the assembly of the secondary battery is more complex, the first embodiment of the present application provides a secondary battery, please refer toFigure 1 、 Figure 2 、 Figure 3 and Figure 4 The secondary battery comprises a shell 100, an electrode assembly 200 and a cover plate assembly 300, the shell 100 has a receiving cavity 110; the electrode assembly 200 is arranged in the receiving cavity 110, and the electrode assembly 200 comprises a body 210 and a tab 220 connected to the body 210; the cover plate assembly 300 comprises a plate body 310, a connecting piece 320 and a pole 330, the plate body 310 has a pole hole 311, the plate body 310 is connected with the shell 100 and covers the receiving cavity 110; the connecting piece 320 is arranged in the receiving cavity 110 and connected with the plate body 310, and the connecting piece 320 is connected with the tab 220; the pole 330 comprises a main body part 331 and a first limiting part 332, the main body part 331 is arranged in the pole hole 311; the first limiting part 332 surrounds the main body part 331 and is connected with the main body part 331 along a direction perpendicular to the thickness direction X of the plate body 310, and the connecting piece 320 is connected to one side of the first limiting part 332 close to the plate body 310.

[0049] Specifically, the pole hole 311 penetrates the plate body 310 along the thickness direction X of the plate body 310, wherein the thickness direction X of the plate body 310 is the direction of the arrow X in the drawing.

[0050] In some embodiments, the plate body 310 and the connecting piece 320 are insulated, and specifically, a sealing member 340 is arranged between the plate body 310 and the connecting piece 320, the sealing member 340 can insulate the connecting piece 320 and the plate body 310 to avoid short circuit of the connecting piece 320 and the plate body 310.

[0051] In some embodiments, the first limiting part 332 and the main body part 331 are in an integral structure.

[0052] In some embodiments, the first limiting part 332 is formed by folding outwardly from the main body part 331 along the direction perpendicular to the thickness direction X of the plate body 310.

[0053] In some embodiments, the first limiting part 332 is welded with the connecting piece 320.

[0054] In the above embodiment, the connecting piece 320 located in the accommodating cavity 110 and connected with the pole column 330 is connected with the plate body 310, which can limit the movement of the pole column 330 along the thickness direction X of the plate body 310 away from the electrode assembly 200, thereby achieving the same effect as the welding block, and at the same time, the connecting piece 320 still retains the original function of the connecting piece 320, that is, electrically connecting the pole column 330 and the tab 220, that is, the connecting piece 320 in the above embodiment can not only electrically connect the pole column 330 and the tab 220, but also limit the pole column 330. Therefore, in the above embodiment, it is not necessary to additionally provide a welding block to limit the pole column 330, which can reduce the types and quantities of parts in the secondary battery, reduce the process steps during assembly of the secondary battery, and also reduce the assembly difficulty of the secondary battery.

[0055] In some embodiments, referring to Figure 2 , Figure 5 , Figure 6 and Figure 7 , the first limiting portion 332 has a maximum size L1 in the direction perpendicular to the thickness direction X of the plate body 310, which satisfies: 0.5mm≤L1≤1.2mm.

[0056] Specifically, the value of L1 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm. The larger the value of L1, the larger the connecting surface 3321 of the first limiting portion 332 and the connecting piece 320, and the more reliable the connection of the first limiting portion 332 and the connecting piece 320. The smaller the value of L1, the less material the pole column 330 uses, and the greater the mass energy density of the secondary battery. When the value of L1 is within the range defined in the present application, the connection of the first limiting portion 332 and the connecting piece 320 is reliable, and the mass energy density of the secondary battery is relatively large.

[0057] In the above embodiment, by limiting the value of L1, the connection of the first limiting portion 332 and the connecting piece 320 is reliable, the mass of the secondary battery is small, so that the mass energy density of the secondary battery is relatively large.

[0058] In some embodiments, referring to Figure 4 and Figure 6 , the cover plate assembly 300 further comprises a sealing piece 340, the sealing piece 340 comprises a first portion 341 and a second portion 342, the first portion 341 is provided through the pole column hole 311, the first portion 341 is arranged between the pole column 330 and the plate body 310 in the direction perpendicular to the thickness direction X of the plate body 310, and is connected with the pole column 330 and the plate body 310 respectively; the second portion 342 is connected to the side of the first portion 341 close to the connecting piece 320, part of the second portion 342 is arranged between the plate body 310 and the connecting piece 320, and is connected with the plate body 310 and the connecting piece 320 respectively.

[0059] Specifically, the sealing member 340 is a sealing ring capable of elastic deformation, and the sealing member 340 is sleeved on the pole column 330.

[0060] In the above embodiment, the first part 341 is clamped between the pole column 330 and the plate body 310 in a direction perpendicular to the thickness direction X of the plate body 310, so as to realize the sealed connection of the pole column 330 and the plate body 310, so that the accommodation cavity 110 is isolated from the outside of the secondary battery. The second part 342 can extend the sealing path and further improve the sealing effect of the sealing member 340. At the same time, the second part 342 is also used to connect the connecting sheet 320 and the plate body 310, so as to realize the limiting action of the plate body 310 on the pole column 330, avoiding the movement of the pole column 330 along the thickness direction X of the plate body 310 to the direction away from the electrode assembly 200. In addition, in some embodiments, the sealing member 340 is an insulating member, which can insulate the pole column 330 and the plate body 310, and can also insulate the connecting sheet 320 and the plate body 310, avoiding the internal short circuit of the secondary battery, and improving the use reliability of the secondary battery.

[0061] In some embodiments, referring to Figure 4 and Figure 6 , the pole column 330 further comprises a second limiting part 333 and a protruding part 334. The second limiting part 333 is arranged on the side of the plate body 310 away from the electrode assembly 200, and surrounds the main body part 331 and is connected with the main body part 331 in a direction perpendicular to the thickness direction X of the plate body 310. The plate body 310 is clamped between the second limiting part 333 and the connecting sheet 320. The protruding part 334 surrounds the main body part 331 and is connected with the main body part 331 in a direction perpendicular to the thickness direction X of the plate body 310. The protruding part 334 has a first sealing surface 3341 and a second sealing surface 3342 connected with each other. The first sealing surface 3341 is connected with the first part 341, and the second sealing surface 3342 faces the connecting sheet 320. Part of the second part 342 is arranged between the connecting sheet 320 and the second sealing surface 3342, and is connected with the connecting sheet 320 and the second sealing surface 3342, respectively.

[0062] It can be understood that the connecting sheet 320 is arranged on the side of the plate body 310 close to the electrode assembly 200, so as to avoid the movement of the pole column 330 along the thickness direction X of the plate body 310 to the direction away from the electrode assembly 200. Correspondingly, in the above embodiment, the second limiting part 333 arranged on the side of the plate body 310 away from the electrode assembly 200 is used to avoid the movement of the pole column 330 along the thickness direction X of the plate body 310 to the direction close to the electrode assembly 200.

[0063] In the above embodiment, the plate body 310 is clamped between the second limiting portion 333 and the connecting sheet 320 to limit the pole column 330. Meanwhile, the protruding portion 334 can increase the size of the contact part between the pole column 330 and the first portion 341 in the direction perpendicular to the thickness direction X of the plate body 310, so that the elastic deformation degree of the first portion 341 is larger, and the sealing effect of the first portion 341 is better. In addition, the protruding portion 334 connected to the second limiting portion 333 near the electrode assembly 200 side can cooperate with the connecting sheet 320 to clamp the second portion 342, so that the elastic deformation degree of the second portion 342 in the thickness direction X of the plate body 310 is larger, and the sealing effect of the second portion 342 is better.

[0064] In some embodiments, the first limiting portion 332 is obtained by outwardly turning the main portion 331 along the pole column 330 toward the plate body 310, and the fixing of the connecting sheet 320 and the first limiting portion 332 needs to be carried out after the outward turning of the first limiting portion 332, that is, the connecting sheet 320 and the pole column 330 are not fixedly connected during the outward turning. During the outward turning, the connecting sheet 320 can move toward the plate body 310, and the protruding portion 334 in the above embodiment can abut against the second portion 342, and the second portion 342 can limit the connecting sheet 320 to a certain extent to avoid the connecting sheet 320 from moving toward the plate body 310, thereby limiting the connecting sheet 320 not fixedly connected with the pole column 330 to a certain extent, reducing the connection difficulty of the connecting sheet 320 and the pole column 330, and further reducing the assembly difficulty of the secondary battery.

[0065] In some embodiments, referring to Figure 7 , the second sealing surface 3342 has a minimum size L2 in the direction perpendicular to the thickness direction X of the plate body 310, and L2 satisfies: L2≥0.8mm.

[0066] Specifically, the value of L2 can be 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm. The larger the value of L2 is, the better the limiting effect of the protruding portion 334 on the connecting sheet 320 not fixedly connected with the pole column 330 is. The smaller the value of L2 is, the greater the thickness of the first portion 341 in the direction perpendicular to the thickness direction X of the plate body 310 is, and the better the sealing effect is. When the value of L2 is within the range defined in the present application, both the limiting effect of the protruding portion 334 on the connecting sheet 320 not fixedly connected with the pole column 330 and the sealing effect of the first portion 341 can be ensured.

[0067] In the above embodiment, the value of L2 is limited so that the protrusion 334 has a better limiting effect on the connecting tab 320 which is not fixedly connected with the pole 330, thereby reducing the difficulty of fixedly connecting the connecting tab 320 with the pole 330. In addition, the first part 341 has a better sealing effect, thereby improving the use reliability of the secondary battery.

[0068] In some embodiments, referring to Figure 4 、 Figure 6 and Figure 7 , the connecting tab 320 comprises an extruding part 321 and a connecting part 322. The extruding part 321 has a mounting hole 3211, the first limiting part 332 passes through the mounting hole 3211 and is connected with the extruding part 321, the second part 342 is connected with the extruding part 321, the extruding part 321 has a first surface 3214 which faces the electrode assembly 200. The connecting part 322 is connected with the extruding part 321 along a direction perpendicular to the thickness direction X of the plate body 310, the connecting part 322 surrounds the extruding part 321, the connecting part 322 has a second surface 3221, the tab 220 is connected with the second surface 3221, the second surface 3221 faces the electrode assembly 200, and the first surface 3214 and the second surface 3221 are flush. Along the thickness direction X of the plate body 310, the extruding part 321 has a maximum dimension H, and the connecting part 322 has a maximum dimension H3, and H>H3 is satisfied.

[0069] It can be understood that, as known from the foregoing, the connecting tab 320 not only plays a role of cooperating with the second limiting part 333 to clamp the plate body 310, but also plays a role of connecting the connecting tab 320.

[0070] Since the first surface 3214 and the second surface 3221 are flush, and H>H3, i.e., the thickness of the extruding part 321 is greater than the thickness of the connecting part 322, and the distance between the extruding part 321 and the plate body 310 is less than the distance between the connecting part 322 and the plate body 310. In the above embodiment, the extruding part 321 can better extrude the second part 342 along the thickness direction X of the plate body 310, so that the sealing effect of the second part 342 is better. At the same time, the use of the connecting part 322 can be reduced, thereby reducing the mass of the connecting tab 320, and further reducing the mass of the secondary battery, so that the mass energy density of the secondary battery is greater, and the performance of the secondary battery is better.

[0071] In some embodiments, referring to Figure 6 and Figure 7 , along the thickness direction X of the plate body 310, the extruding part 321 has a maximum distance H, and 1.2mm≤H≤2.5mm is satisfied.

[0072] Specifically, the value of H can be 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm. The larger the value of H is, the better the extrusion effect of the extrusion part 321 on the second part 342 is, the greater the elastic deformation degree of the second part 342 is, and the better the sealing effect of the sealing piece 340 is. The smaller the value of H is, the less material the extrusion part 321 uses, the smaller the mass of the connecting piece 320 is, the greater the mass energy density of the secondary battery is, and the better the performance of the secondary battery is. When the value of H is within the range defined in the present application, both the sealing effect of the sealing piece 340 and the mass of the connecting piece 320 can be ensured to be small.

[0073] In the above embodiment, by limiting the value of H, the extrusion effect of the extrusion part 321 on the second part 342 is good, so that the sealing effect of the sealing piece 340 is better, and the use reliability of the secondary battery is better; in addition, the mass of the connecting piece 320 can also be small, thereby improving the mass energy density of the secondary battery.

[0074] In some embodiments, please refer to Figure 6 and Figure 7 The mounting hole 3211 has a first hole wall 3212 and a second hole wall 3213 connected to each other, the first hole wall 3212 is connected to the main body part 331, and the second hole wall 3213 is connected to the first limiting part 332; along the thickness direction X of the plate body 310, the first hole wall 3212 has a maximum size H1, which satisfies: H1≥0.2m.

[0075] Specifically, the value of H1 can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm. The larger the value of H1 is, the greater the connecting surface 3321 of the connecting piece 320 and the pole 330 is, which can avoid the inclination of the connecting piece 320 during fixed connection, and reduce the connection difficulty of the connecting piece 320 and the pole 330. The smaller the value of H1 is, the less material the extrusion part 321 uses, the smaller the mass of the connecting piece 320 is, the greater the mass energy density of the secondary battery is, and the better the performance of the secondary battery is. When the value of H1 is within the range defined in the present application, both the connection difficulty of the connecting piece 320 and the pole 330 and the mass of the connecting piece 320 can be ensured to be small.

[0076] In the above embodiments, by limiting the value of H1 to make the connecting surface 3321 of the connecting piece 320 and the pole 330 larger, the connecting piece 320 can be prevented from tilting when fixedly connected, thereby reducing the connection difficulty of the connecting piece 320 and the pole 330; in addition, the mass of the connecting piece 320 can also be smaller, thereby improving the mass energy density of the secondary battery.

[0077] In some embodiments, along the thickness direction X of the plate body 310, the connecting part 322 has a maximum size H3, which satisfies: 0.3mm≤H3≤1.5mm.

[0078] Specifically, the value of H3 can be 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm. The larger the value of H3, the better the mechanical properties of the connecting part 322, which is not easy to bend. The smaller the value of H3, the less material is used for the connecting part 322, the smaller the mass of the connecting piece 320, the larger the mass energy density of the secondary battery, and the better the performance of the secondary battery. When the value of H3 is within the range defined in the present application, the reliability of the connecting piece 320 can be ensured, and the mass of the connecting piece 320 can be smaller.

[0079] In the above embodiments, by limiting the value of H3 to avoid bending of the connecting piece 320, the reliability of the connecting piece 320 is improved, and the reliability of the secondary battery is further improved; in addition, the mass of the connecting piece 320 can also be smaller, thereby reducing the mass of the secondary battery and further improving the mass energy density of the secondary battery.

[0080] In some embodiments, please refer to Figure 6 , Figure 7 and Figure 8 , along the direction perpendicular to the thickness direction X of the plate body 310, the extrusion part 321 has a minimum size L3, and the second part 342 has a minimum size L4, which satisfies: L3-L4≥0.5mm.

[0081] Specifically, the value of L3-L4 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3.0 mm. The greater the value of L3-L4, the greater the contact area of the extrusion portion 321 and the second portion 342, even if the second portion 342 increases in size after being extruded, the extrusion portion 321 can be in full contact with the second portion 342 towards the electrode assembly 200, so that the sealing effect of the second portion 342 is better. The smaller the value of L3-L4, the less material the extrusion portion 321 uses, the smaller the mass of the connecting tab 320, the greater the mass energy density of the secondary battery, and the better the performance of the secondary battery. When the value of L3-L4 is within the range defined in the present application, both the sealing effect of the second portion 342 and the mass of the connecting tab 320 can be ensured to be small.

[0082] In the above embodiments, by limiting the value of L3-L4 to make the sealing effect of the second portion 342 better, the reliability of the secondary battery is improved; in addition, the mass of the connecting tab 320 can also be made smaller, thereby reducing the mass of the secondary battery, and further improving the mass energy density of the secondary battery.

[0083] In some embodiments, referring to Figure 6 , Figure 9 and Figure 10 , the extrusion portion 321 also has a first accommodating groove 3215, the first accommodating groove 3215 penetrates through the first surface 3214, the first accommodating groove 3215 is arranged around the mounting hole 3211, and the first accommodating groove 3215 communicates with the mounting hole 3211.

[0084] It can be understood that in some embodiments, the pole post 330 is welded to the connecting tab 320, and a weld reinforcement will be generated after the pole post 330 and the connecting tab 320 are welded. In the above embodiments, the first accommodating groove 3215 is provided to accommodate the weld reinforcement left when the pole post 330 and the connecting tab 320 are welded, so as to avoid the weld reinforcement protruding from the connecting tab 320 and contacting other components to cause short circuit, thereby improving the use reliability of the secondary battery.

[0085] In some embodiments, referring to Figure 7 , along the thickness direction X of the plate body 310, the first accommodating groove 3215 has a maximum size H2, which satisfies: H2≥0.15 mm.

[0086] Specifically, the value of H2 can be 0.15 mm, 0.25 mm, 0.35 mm, 0.45 mm, 0.55 mm, 0.65 mm, 0.75 mm, 0.85 mm, 0.95 mm, 1.05 mm. The larger the value of H2 is, the larger the size of the first accommodating groove 3215 along the thickness direction X of the plate body 310 is, and the larger the size of the connecting surface 3321 of the extrusion part 321 and the pole piece 330 along the thickness direction X is, and the larger the area of the connecting surface 3321 is, and the more stable the connection between the connecting piece 320 and the pole piece 330 is. When the value of H2 is within the range defined in the present application, the first accommodating groove 3215 can better accommodate the weld reinforcement, and the connection between the connecting piece 320 and the pole piece 330 is better, and the reliability of the secondary battery is improved.

[0087] In the above embodiment, by limiting the value of H2, the first accommodating groove 3215 can better accommodate the weld reinforcement, and the reliability of the secondary battery is improved; in addition, the connection between the connecting piece 320 and the pole piece 330 is better, and the connection is more stable, and the reliability of the secondary battery is also improved.

[0088] In some embodiments, please refer to Figure 4 , the minimum distance between the connecting piece 320 and the shell 100 along the direction perpendicular to the thickness direction X of the plate body 310 is G, which satisfies: G≥2 mm.

[0089] Specifically, the value of G can be 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm. The larger the value of G is, the less likely the connecting piece 320 is to contact the shell 100, and the probability of short circuit between the connecting piece 320 and the shell 100 is reduced, and the reliability of the secondary battery is improved. The smaller the value of G is, the larger the size of the connecting part 322 along the direction perpendicular to the thickness direction X of the plate body 310 is, and the difficulty of connecting the connecting part 322 and the tab 220 is reduced, and the structure of the secondary battery is more compact. When the value of G is within the range defined in the present application, the reliability of the secondary battery is better, and the structure of the secondary battery is more compact.

[0090] In the above embodiment, by limiting the value of G, the connecting piece 320 and the shell 100 have enough spacing to avoid the connecting piece 320 and the shell 100 from contacting and causing short circuit, and the reliability of the secondary battery is improved; in addition, the difficulty of connecting the connecting piece 320 and the tab 220 is reduced, and the structure of the secondary battery is more compact.

[0091] In some embodiments, please refer to Figure 6The plate body 310 further has a second accommodating groove 312, which is arranged around the pole hole 311 and communicates with the pole hole 311, and an opening of the second accommodating groove 312 faces the connecting piece 320, and a part of the second part 342 is arranged in the second accommodating groove 312.

[0092] In the above embodiment, by arranging the second accommodating groove 312 to accommodate at least part of the second part 342 along the thickness direction X of the plate body 310, the space occupied by the second part 342 along the thickness direction X of the plate body 310 in the accommodating cavity 110 is reduced, so that the structure of the secondary battery is more compact.

[0093] Correspondingly, the application further provides a battery pack comprising the secondary battery according to any one of the above embodiments.

[0094] The above describes in detail the secondary battery and the battery pack provided by the embodiments of the application. The principles and implementation manners of the application are described by applying specific examples in the application. The above embodiment is only used to help understand the technical solutions and the core ideas of the application. 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 by equivalents; and the 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 application.

Claims

1. A secondary battery characterized by comprising: The application relates to a secondary battery, which comprises a shell having a receiving cavity, an electrode assembly arranged in the receiving cavity, the electrode assembly comprising a body and a tab connected to the body, and a cover plate assembly comprising a plate body having a pole post hole, the plate body being connected to the shell and covering the receiving cavity, a connecting piece arranged in the receiving cavity and connected to the plate body, and a pole post comprising a main body part and a first limiting part, the main body part being arranged in the pole post hole, the first limiting part being connected to the main body part in a direction perpendicular to the thickness direction of the plate body, and the connecting piece being connected to the first limiting part on the side close to the plate body. In the direction perpendicular to the thickness direction of the plate body, the first limiting part has a maximum size L1, which satisfies 0.5mm<=L1<=1.2mm.

3. The secondary battery according to claim 1, wherein the cover plate assembly further comprises a sealing member, the sealing member comprising a first part arranged in the pole post hole and connected to the pole post and the plate body respectively in the direction perpendicular to the thickness direction of the plate body, and a second part connected to the first part on the side close to the connecting piece, and part of the second part being arranged between the plate body and the connecting piece and connected to the plate body and the connecting piece respectively. The pole post further comprises a second limiting part arranged on the side of the plate body away from the electrode assembly, the second limiting part surrounding the main body part and connected to the main body part in the direction perpendicular to the thickness direction of the plate body, the plate body being arranged between the second limiting part and the connecting piece, and a protruding part surrounding the main body part and connected to the main body part in the direction perpendicular to the thickness direction of the plate body, the protruding part having a first sealing surface and a second sealing surface connected to each other, the first sealing surface being connected to the first part, and the second sealing surface facing the connecting piece, and part of the second part being arranged between the connecting piece and the second sealing surface and connected to the connecting piece and the second sealing surface respectively.

2. The secondary battery according to claim 1, characterized by In the direction perpendicular to the thickness direction of the plate body, the second sealing surface has a minimum size L2, which satisfies L2>=0.8mm. The connecting piece comprises an extruding part having a mounting hole, the first limiting part being arranged in the mounting hole and connected to the extruding part, the second part being connected to the extruding part, the extruding part having a first surface facing the electrode assembly, and a connecting part connected to the extruding part in the direction perpendicular to the thickness direction of the plate body, the connecting part surrounding the extruding part, the connecting part having a second surface, the tab being connected to the second surface, the second surface facing the electrode assembly, and the first surface and the second surface being flush. In the thickness direction of the plate body, the extruding part has a maximum size H, and the connecting part has a maximum size H3, which satisfies H>H3. ​ ​ 4. The secondary battery according to claim 3, characterized by ​ ​ ​ 5. The secondary battery according to claim 4, characterized by ​ 6. The secondary battery according to claim 3, characterized by ​ ​ ​ ​ 7.The secondary battery according to claim 6, wherein the extruded portion has a maximum distance H in a thickness direction of the plate body, and 1.2 mm ≤ H ≤ 2.5 mm is satisfied; and / or, the mounting hole has a first hole wall connected to the main body portion and a second hole wall connected to the first stop portion, the first hole wall has a maximum size H1 in the thickness direction of the plate body, and H1 ≥ 0.2 mm is satisfied; and / or, the connecting portion has a maximum size H3 in the thickness direction of the plate body, and 0.3 mm ≤ H3 ≤ 1.5 mm is satisfied; and / or, the extruded portion has a minimum size L3 in a direction perpendicular to the thickness direction of the plate body, and the second portion has a minimum size L4, and L3-L4 ≥ 0.5 mm is satisfied. The extruded portion further has a first receiving groove penetrating through the first surface, the first receiving groove is disposed around the mounting hole, and the first receiving groove is in communication with the mounting hole. The first receiving groove has a maximum size H2 in the thickness direction of the plate body, and H2 ≥ 0.15 mm is satisfied. A secondary battery as claimed in any one of claims 1-9. ​ 8. The secondary battery according to claim 6, characterized by ​ 9. The secondary battery according to claim 8, characterized by ​ 10. A battery pack, characterized by, ​

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