CN109428017B

CN109428017B - Secondary battery and battery module

Info

Publication number: CN109428017B
Application number: CN201710765949.4A
Authority: CN
Inventors: 李全坤
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2017-08-30
Filing date: 2017-08-30
Publication date: 2020-11-20
Anticipated expiration: 2037-08-30
Also published as: CN109428017A; CN112271412B; CN112271412A

Abstract

The invention provides a secondary battery and a battery module. The secondary battery includes: a housing having an opening; an electrode assembly including a first pole piece, a second pole piece, and a separator disposed between the first pole piece and the second pole piece; a top cap assembly including a top cap plate covering the opening and having an electrode lead-out hole, and a first electrode terminal including a terminal plate located at one side of the top cap plate and covering the electrode lead-out hole; the terminal plate comprises a main body part and an extension part connected with the main body part, the main body part is positioned on one side of the top cover plate, which is far away from the terminal plate, and is connected with the first pole piece, and the extension part extends into the electrode leading-out hole and is connected with the first electrode terminal; and a sealing member disposed between the top cover plate and the terminal plate and surrounding the extension portion to seal the electrode lead-out hole. The space utilization rate inside the secondary battery shell can be improved, so that the energy density of the secondary battery is improved, and one or more purposes of preventing the electrolyte inside the secondary battery shell from leaking are achieved.

Description

Secondary battery and battery module

Technical Field

The invention relates to the technical field of energy storage devices, in particular to a secondary battery and a battery module.

Background

New energy automobiles are widely popularized in China and even in the world, but a great number of places need to be improved if fuel automobiles are completely replaced. For example, the problems of a small driving range of an automobile, a high cost of a battery pack, and reliability of the battery pack need to be further solved. Based on the above problems, higher requirements are put on the core part power battery of the electric vehicle, such as the need of achieving higher energy density, lower cost and the like of the power battery.

At present, a power battery shell comprises a shell body and a top cover plate assembly, wherein the shell provides a closed space for accommodating an electric core and electrolyte, and electric energy of the electric core is led out of the closed space from the inside of the closed space through a pole of the top cover plate assembly. In the existing top cover plate assembly, a top cover plate is a metal plate and is provided with a through hole, a pole is divided into a base body part and an extension part, and the cross sectional area of the base body part is larger than the aperture of the through hole. During the assembly, the base part is located the below of lamina tecti (inside the casing promptly), treats that the extension passes behind the through-hole and utilizes the jump ring or adopt the riveting mode fixed extension, fixes utmost point post in lamina tecti through this mode. Since the base portion is located inside the case, the space utilization rate inside the case is reduced, and the energy density of the power battery is reduced. Further, since the pole needs to be provided with the base portion and the long extension portion, the pole cannot be directly press-molded and needs to be individually machine-formed, so that the manufacturing cost of the pole is increased.

Therefore, a new secondary battery and a battery module are needed.

Disclosure of Invention

According to the embodiment of the invention, the secondary battery and the battery module can achieve one or more purposes of improving the space utilization rate inside the secondary battery shell, improving the energy density of the secondary battery and preventing the electrolyte inside the secondary battery shell from leaking.

According to an aspect of an embodiment of the present invention, there is provided a secondary battery including: a housing having an opening; an electrode assembly accommodated in the case, including a first pole piece, a second pole piece, and a separator disposed between the first pole piece and the second pole piece; a top cap assembly including a top cap plate covering the opening and having an electrode lead-out hole, and a first electrode terminal including a terminal plate located at one side of the top cap plate and covering the electrode lead-out hole; the terminal plate comprises a main body part and an extension part connected with the main body part, the main body part is positioned on one side of the top cover plate, which is far away from the terminal plate, and is connected with the first pole piece, and the extension part extends into the electrode leading-out hole and is connected with the first electrode terminal; and a sealing member disposed between the top cover plate and the terminal plate and surrounding the extension portion to seal the electrode lead-out hole.

According to one aspect of an embodiment of the invention, at least a portion of the seal is in contact with and compressed between the top cover plate and the body portion, respectively.

According to an aspect of the embodiment of the present invention, the main body part and the extension part are of a unitary structure, the extension part includes a protrusion disposed on a side of the main body part close to the top cover plate, and a recess is formed on a side of the main body part far from the top cover plate by disposing the protrusion.

According to an aspect of the embodiment of the invention, the material of the main body portion and the material of the extension portion have the same base metal, and the material of the extension portion and the material of the first electrode terminal have different base metals.

According to an aspect of an embodiment of the present invention, the extension further includes conductive blocks welded to the projection and the terminal plate, respectively.

According to an aspect of an embodiment of the present invention, the protrusion and the conductive block have different base metals, and the conductive block and the first electrode terminal have the same base metal.

According to an aspect of the embodiment of the present invention, a surface of the terminal plate on a side away from the top cover plate is provided with a groove.

According to an aspect of the embodiment of the present invention, the seal member is of an annular structure, the seal member includes an axially extending portion compressed between the extending portion and an inner wall of the electrode lead-out hole, and a radially extending portion compressed between the main body portion and a surface of the top lid plate remote from the terminal plate.

According to an aspect of an embodiment of the present invention, the top cap assembly further includes a lower insulating member disposed between the top cap plate and the main body part to maintain insulation between the top cap plate and the wiring board, and the lower insulating member has a first through hole corresponding to the electrode lead-out hole.

According to an aspect of an embodiment of the present invention, the sealing member further includes a first flange formed on an outer circumferential surface of the sealing member in a radial direction and compressed between the lower insulator and the top cover plate.

According to an aspect of an embodiment of the present invention, the lower insulator is snap-connected to the wiring board.

According to one aspect of the embodiment of the invention, the lower insulating member comprises a nail body and a limiting part which are connected with each other, one end of the nail body is connected with the limiting part, the other end of the nail body is fixedly connected with the lower insulating member, the cross-sectional area of the limiting part is larger than that of the nail body, a second through hole is correspondingly arranged on the wiring board, the nail body penetrates through the second through hole, and the limiting part abuts against the surface of the side, far away from the top cover plate, of the wiring board.

According to an aspect of the embodiment of the present invention, further comprising a fixing member and a connecting member, the fixing member being fixed to the top cap plate by the connecting member, an outer circumferential surface of the first electrode terminal being at least partially surrounded by the fixing member to fix the first electrode terminal to the fixing member.

According to an aspect of an embodiment of the present invention, the fixing member further includes a second raised edge formed on a side of the fixing member facing the top cover plate and protruding into the electrode lead-out hole, and the sealing member is in close contact with the fixing member, the top cover plate, the lower insulating member, and the wiring board at the same time.

According to an aspect of the embodiment of the present invention, a receiving groove surrounding the electrode lead-out hole is provided on a surface of the top cap plate on a side away from the terminal plate, and the sealing member is received in the receiving groove.

According to another aspect of the embodiments of the present invention, there is also provided a battery module including: and the above-described secondary battery, the bus bar being welded to the terminal plate, the bus bar being made of the same base metal as the terminal plate.

In summary, the secondary battery and the battery module according to the embodiment of the present invention configure the wiring board located inside the case to include the main body portion and the extension portion connected to the main body portion. The top cover plate is provided with an electrode leading-out hole, the main body part of the wiring board is positioned on one side of the top cover plate, which faces the shell, is insulated from the top cover plate through the lower insulating piece, is connected with the first pole piece in the electrode assembly positioned in the shell through the main body part, and extends into the electrode leading-out hole through the extending part to be connected with the first electrode terminal arranged on the top cover plate. The purpose of electrically connecting the first pole piece in the electrode assembly to the first electrode terminal can be achieved through the wiring board. And a sealing member is disposed between the top cover plate and the wiring board around the electrode lead-out hole of the top cover plate to seal the electrode lead-out hole. Therefore, the secondary battery and the battery module provided by the embodiment of the invention can improve the space utilization rate in the secondary battery shell, thereby improving the energy density of the secondary battery, ensuring the sealing property of the electrode leading-out hole and avoiding the problem of electrolyte leakage of the secondary battery.

Drawings

The invention may be better understood from the following description of specific embodiments thereof taken in conjunction with the accompanying drawings, in which:

other features, objects and advantages of the invention will become apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings in which like or similar reference characters refer to the same or similar parts.

Fig. 1 is an exploded structural view of a secondary battery according to an embodiment of the present invention;

fig. 2 is an exploded structural view of a cap assembly in the secondary battery of fig. 1;

fig. 3 is a schematic top view of the secondary battery of fig. 1;

FIG. 4 is a schematic sectional view of the secondary battery of FIG. 3 taken along the section line A-A;

fig. 5 is a partially enlarged schematic view of a portion a of the secondary battery of fig. 4;

fig. 6 is a schematic perspective view of a wiring board in the secondary battery of fig. 1, 4 and 5;

fig. 7 is a schematic sectional view of a secondary battery according to another embodiment of the present invention, taken along the direction a-a;

fig. 8 is a partially enlarged schematic view of a structure of a portion B in the secondary battery of fig. 7;

fig. 9 is a schematic perspective view of a wiring board in the secondary battery of fig. 7 and 8;

FIG. 10 is a perspective view of the patch panel of FIG. 9 in an exploded condition;

FIG. 11 is a schematic sectional view of the secondary battery of FIG. 4 taken along section line B-B;

fig. 12 is a partially enlarged schematic view of the structure of part C in the secondary battery of fig. 11;

fig. 13 is an enlarged view of the seal member of the cap assembly of fig. 2 taken along an axial center plane.

Wherein:

1-a secondary battery; 2-a secondary battery; 100-a cap assembly; 200-a housing; 300-an electrode assembly; 310-a first tab; 320-a second tab; 400-insulating protective layer; 500-patch panel; 510-a body portion; 510 a-a second via; 511-a substrate; 512-wing plate; 520-an extension; 530-conductive blocks; 501-patch panel;

10-a top cover plate; 11-electrode leading-out hole; 12-riveting; 121-nail body; 122-a limiting part; 13-a second groove; 14-liquid injection hole; 15-an explosion-proof valve assembly;

20-a terminal assembly; 21-terminal plate; 21 a-a groove; 22-a fixing member; 221-an accommodation space; 222-a connection hole; 223-an annular rim; 23-a seal; 231-an axial extension; 232-a radial extension; 233-annular rim; 24-a stop block;

30-an electrode terminal; 31-terminal plate; 32-a fastener; 33-a seal;

40-lower insulator; 41-a first insulator; 42-riveting piece; 421-a nail body; 422-limiting part.

Detailed Description

Features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. In the drawings and the following description, at least some well-known structures and techniques have not been shown in detail in order to avoid unnecessarily obscuring the present invention; also, the dimensions of some of the structures may be exaggerated for clarity. The same reference numerals denote the same or similar structures in the drawings, and thus detailed descriptions thereof will be omitted. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The directional terms appearing in the following description are directions shown in the drawings, and do not limit the specific structure of the secondary battery of the present invention. In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be directly connected or indirectly connected. The specific meaning of the above terms in the present invention can be understood as appropriate to those of ordinary skill in the art.

The secondary battery provided by the embodiment of the invention can be used for multiple times by circularly performing charging and discharging operations, and the energy density of the secondary battery can be improved by reducing the occupancy rate of the internal space of the shell, and the electrolyte in the shell of the secondary battery can be prevented from leaking, so that the use reliability of the secondary battery can be improved.

For a better understanding of the present invention, a secondary battery according to an embodiment of the present invention will be described below with reference to fig. 1 to 13.

Fig. 1 is an exploded structural view of a secondary battery 1 according to one embodiment of the present invention. As shown in fig. 1, the secondary battery 1 generally includes: a cap assembly 100, a case 200, and an electrode assembly 300, an insulating shield layer 400, and a terminal plate 500 located inside the case 200.

According to one embodiment of the present invention, the case 200 may be made of a metal material, such as aluminum, aluminum alloy, or nickel-plated steel. The case 200 is formed in a rectangular box shape and has an opening to communicate the receiving space inside thereof through the opening.

The electrode assembly 300 may be formed by stacking or winding a first pole piece, a second pole piece, and a separator, which is an insulator between the first pole piece and the second pole piece. In this embodiment, the first electrode tab is exemplarily described as a positive electrode tab, and the second electrode tab is exemplarily described as a negative electrode tab. Similarly, in other embodiments, the first pole piece can also be a negative pole piece, and the second pole piece can be a positive pole piece. In addition, the positive electrode sheet active material may be coated on the coating region of the positive electrode sheet, and the negative electrode sheet active material may be coated on the coating region of the negative electrode sheet. The part extending from the coating area of the positive plate is used as a positive tab, namely a first tab 310; the portion extending from the coated region of the negative plate serves as a negative tab, i.e., the second tab 320.

The insulating shield layer 400 is a thin film-shaped shield layer composed of an insulating material, and is formed to have a receiving space adapted to the contour of the electrode assembly 300, so as to maintain electrical insulation between the electrode assembly 300 and the inner wall of the case 200 by wrapping the insulating shield layer 400 around the outer circumference of the electrode assembly 300. In addition, an insulating layer may be disposed on the inner surface of the case 200 instead of the insulating protective layer 400.

Fig. 2 is an exploded structural view of the cap assembly 100 of the secondary battery 1 of fig. 1; fig. 3 is a schematic top view of the secondary battery 1 of fig. 1; fig. 4 is a schematic cross-sectional view of the secondary battery 1 shown in fig. 3 taken along the line a-a. As shown in fig. 2 to 4, the cap assembly 100 is used to seal the case 200 to seal the electrode assembly 300 within the case 200. The cap assembly 100 includes: a top cover plate 10, a terminal assembly 20, a terminal assembly 30, and a lower insulator 40.

The top cover plate 10 is thin plate-shaped and has a size and shape matching the opening of the case 200 so as to be attachable to the opening of the case 200. The top cover plate 10 is made of a metal material, and for example, the same metal material as that of the housing 200 may be selected. In the present embodiment, the top lid plate 10 is provided with two electrode lead-out holes 11, a rivet 12, a second recess 13, a liquid injection hole 14, and an explosion-proof valve assembly 15.

In one exemplary embodiment, a terminal assembly 20 and a terminal assembly 30 are respectively disposed at two electrode lead-out holes 11 of the top cover plate 10, the terminal assembly 20 generally including a first electrode terminal, a fixing member 22, and a sealing member 23; likewise, the terminal assembly 30 generally includes a second electrode terminal, a fixing member 32, and a sealing member 33. Since in the present embodiment, only the structure of the terminal assembly 20 and its mounting form on the top cover plate 10 are exemplarily described. Also, without being particularly described, the following description will exemplarily be made in such a manner that the terminal assembly 20 is a positive terminal assembly, and the terminal assembly 30 is a negative terminal assembly. Illustratively, the first electrode terminal includes a terminal plate 21, and the second electrode terminal includes a terminal plate 31.

As shown in fig. 2 and 4, the pour hole 14 is formed in the top lid 10 in a predetermined size so that the electrolyte can be poured into the accommodating space of the case 200 through the pour hole 14 after the top lid 10 is closed to the opening of the case 200 and sealingly connected to the case 200. The explosion-proof valve assembly 15 may adopt an existing structure (e.g., a manner of providing an explosion-proof sheet), the explosion-proof valve assembly 15 being provided at a substantially middle position of the top cover plate 10, and when the internal pressure of the secondary battery is excessively large due to gas generation due to overcharge, overdischarge, or overheating of the battery, the explosion-proof sheet in the explosion-proof valve assembly 15 may be broken so that the gas formed inside the secondary battery may be discharged to the outside through the through-hole of the explosion-proof valve assembly 15, whereby the secondary battery can be prevented from exploding.

In order to maintain the insulation state between the top cap plate 10 and the electrode assembly 300 and the terminal plate 500 inside the case, the lower insulator 40 is generally made of a plastic material and has a substantially plate shape, which is located on the surface of the top cap plate 10 facing the inside of the case 200. The lower insulating member 40 is provided with two first through holes, and the first insulating member 41 is disposed around one of the first through holes, which are respectively opposite to the two electrode lead-out holes 11 provided on the electrode lead-out hole 11.

In the present embodiment, the first insulating member 41 has a ring shape, and is of an integral structure with the lower insulating member 40, and the first insulating member 41 includes a body portion having a size that is appropriately set to the electrode lead-out hole 11, so that the body portion can be coupled to the upper cover plate 10 by interference fit with the electrode lead-out hole 11 when the first insulating member 41 is inserted into the electrode lead-out hole 11. And an end surface of the body of the first insulating member 41, which is close to the electrode terminal, protrudes from a surface of the top cap plate 10, which is close to the electrode terminal.

With continued reference to fig. 2 to 4, two electrode lead-out holes 11 are formed in the top cover plate 10, and are respectively used for enabling a terminal plate 500 (not shown) located inside the housing 200 to electrically connect the electrode terminals in the terminal assembly 20 and the terminal assembly 30 with one of the first pole piece and the second pole piece in the electrode assembly 300 inside the housing 200.

In an exemplary embodiment, the fixing member 22 is a rigid plastic member, and may be made of a high temperature resistant insulating plastic material by way of integral injection molding, for example, one or more of polyphenylene sulfide PPS, perfluoroalkoxy PEA, or polypropylene PP. So that the fixing member 22 can be closely attached to the first electrode terminal while securing a fastening force with the top cap plate 10.

Fig. 5 is a partially enlarged schematic view of a portion a of the secondary battery 1 of fig. 4. As shown in fig. 2 to 5, specifically, the fixing member 22 has an accommodating space 221 adapted to the shape of the terminal plate 21, and the terminal plate 21 can be accommodated in the accommodating space 221 and fixed in abutment with the terminal plate 21, so that a part of the fixing member 22 is clamped between the terminal plate 21 and the top cover plate 10. In order to increase the fastening force of the terminal plate and the fixing member 22 to each other, an annular projection is provided on the outer peripheral surface of the terminal plate 21, and an annular recess capable of accommodating the annular projection is correspondingly provided on the inner wall surface of the fixing member 22 in contact with the terminal plate 21. When the terminal plate 21 is placed in the receiving space 221 of the holder 22, the annular convex portion and the annular concave portion form a snap-fit structure with each other, thereby enabling the terminal plate 21 to be stably coupled in the holder 22. Alternatively, it is also possible to form an accommodation space between the mount 22 and the top cover plate 10, which accommodates the terminal plate 21 therein, in conformity with the shape of the terminal plate 21 (at this time, the mount 22 does not have a portion sandwiched between the terminal plate 21 and the top cover plate 10). Of course, the fixation referred to herein means that the terminal plate 21 does not move in the thickness direction with respect to the fixing member 22.

After the terminal plate 21 and the fixing member 22 are coupled to each other, the terminal plate 21 covers the electrode lead-out hole 11 and the outer circumferential surface of the terminal plate protrudes from the inner wall of the electrode lead-out hole 11 (i.e., as shown in fig. 5, the cross-sectional dimension of the terminal plate 21 is larger than that of the electrode lead-out hole 11), and the surface of the terminal plate 21 remote from the top cover plate 10 protrudes from the surface of the fixing member 22 remote from the top cover plate 10 (i.e., as shown in fig. 5, the upper surface of the terminal plate is higher than that of the. Meanwhile, a through hole is provided at a side of the fixing member 22 close to the top cap plate 10 so that the terminal plate 21 can be exposed to the inside of the case 200 through the through hole, thereby enabling electrical connection with the electrode assembly 300.

According to one embodiment of the present invention, the terminal plate 21 is electrically connected to the first pole piece in the electrode assembly 300 through the terminal plate 500. The wiring board 500 is located inside the case 200, and the secondary battery 1 has two wiring boards 500, the two wiring boards 500 being disposed corresponding to the positive electrode tab and the negative electrode tab, respectively (as shown in fig. 1). That is, the two terminal plates 500 are used to accomplish the electrical connection between the positive terminal (i.e., the first electrode terminal) and the positive tab (the first tab 310), and the electrical connection between the negative terminal (i.e., the second electrode terminal) and the negative tab (the second tab 320), respectively. In the present embodiment, the structure of the terminal block 500 will be described by taking the terminal block 500 as an example of a transitional connecting member between the terminal block 21 and the first pole piece.

Fig. 6 is a schematic perspective view of the wiring board 500 in the secondary battery 1 of fig. 1, 4, and 5. Referring to fig. 4 to 6, according to one embodiment of the present invention, a terminal block 500 includes a main body portion 510 and an extension portion 520, wherein the main body portion 510 is located at a side of a lower insulator 40 away from a terminal plate 21 for electrical connection with a first tab 310; and the extension part 520 can be extended into the electrode lead-out hole 11 to be electrically connected with the terminal plate 21. Thereby electrically connecting the terminal plate 21 to the first pole piece.

In one embodiment, body portion 510 includes a base 511 and wings 512. The substrate 511 is formed in a flat plate-like structure, and the substrate 511 is parallel to the top cover plate 10. Of course, the parallelism referred to herein is not strictly parallel, i.e., in a particular implementation, errors in the parallelism of the substrate 511 and the top cover plate 10 are allowed, but the result of the substrate 511 and the top cover plate 10 being substantially parallel is not affected. The paddle 512 is formed in a strip-like plate-like structure extending outward along a substantially central position of one side edge of the substrate 511. Thereby, it is possible to electrically connect with the first tab 310 (i.e., electrically connect with the first pole piece) through the substrate 511.

Illustratively, the extension 520 is a protrusion provided on a surface of the main body 510 on a side close to the top cover plate 10. As shown in fig. 4 to 6, in the present embodiment, a projection is provided on the wing panel 512, and a recess is formed on a surface of the wing panel 512 on a side away from the top deck 10 by providing the projection. That is, the projection includes a top wall and an annular side wall connected to the top wall such that the projection is open on the side of the wing panel 512 remote from the top closure panel 10. In an exemplary embodiment, when the main body 510 and the extension 520 are a unitary structure, the extension 520 may be a cylindrical convex hull formed on the wing plate 512 by stamping. In this way, the body portion 510 is attached to the surface of the lower insulator 40 on the side away from the top lid plate 10, so that the extension portion 520 can be inserted into the electrode lead-out hole 11 and brought into contact with the terminal plate 21, and the extension portion 520 and the terminal plate 21 can be welded together.

By providing the concave portion on the side of the wiring board 500 away from the top cover plate 10, more electrolyte can be stored in the case 200, so that the cycle life of the battery can be increased (because the electrolyte is consumed as the battery is charged and discharged); meanwhile, during the charging and discharging of the secondary battery, gas is generated inside the case 200, and the concave portion can also accommodate a certain volume of gas, thereby preventing the case 200 from being expanded and deformed to a certain extent.

Since the substrate 511 has a flat plate-shaped structure, when the first tab 310 of the electrode assembly 300 is coupled to the substrate 511, the first tab 310 needs to be bent such that the first tab 310 can be coupled to the substrate 511 via a bent surface (as shown in fig. 1). Illustratively, the first tab 310 may be coupled to the substrate 511 by ultrasonic welding. Of course, since the main body part 510 is further provided with extension plates at both sides of the wing plates 512 in the present embodiment, two or more sets of electrode assemblies 300 may be simultaneously connected to the main body part 510, so that at least two sets of electrode assemblies 300 may be included in the case 200 of each secondary battery 1. Since the first tab 310 of the electrode assembly 300 is simply connected to the terminal plate 500, the assembly efficiency of the secondary battery 1 can be effectively improved.

The extension 520 is formed by punching a convex hull on the terminal block 500 so that the terminal block 500 can be inserted into the electrode lead-out hole 11 to be electrically connected to the terminal block 21, and the terminal block 21 does not need to be additionally provided with another structure to be electrically connected to the terminal block 500 at the surface of the top cover plate 10 facing the inside of the case 200, that is, the surface of the terminal block 21 facing the inside of the case 200 does not exceed the lower surface of the lower insulator 40. Therefore, the occupation of the internal space of the case 200 can be reduced, and the energy density of the secondary battery can be effectively improved. And the structure and the process of the terminal plate 500 are simple and can be manufactured by a simple cutting and pressing method, so that the processing cost of the secondary battery 1 can be reduced and the processing difficulty of the secondary battery 1 can be reduced.

In addition, since a weld bead and a weld slag are generated after welding, these portions reduce the flatness of the upper surface of the terminal plate 21 (i.e., the surface away from the top cover plate 10), and in order to avoid this problem, the thickness of the terminal plate 21 needs to be larger than the thin thickness of the extension portion 520, the terminal plate 21 and the extension portion 520 are connected by laser welding, laser is emitted from the side of the top cover plate 10 away from the terminal plate 21, the laser penetrates the extension portion 520 and a portion of the terminal plate 21, and a weld bead is formed between the terminal plate 21 and the extension portion 520, and at this time, the upper surface of the terminal plate 21 is kept flat.

In addition, the material of the body portion 510 and the material of the extension portion 520 may have the same base metal, and the material of the extension portion 520 and the material of the first electrode terminal may have different base metals. Illustratively, when the first electrode terminal is a negative electrode terminal, the base metal of the material of the external bus bar is aluminum, the base metal of the terminal plate 21 of the first electrode terminal is aluminum, and the base metal of the material of the main body portion 510 and the extending portion 520 connected to the negative electrode terminal is copper because the negative electrode terminal is made of copper.

Fig. 7 is a schematic sectional view of a secondary battery 2 according to another embodiment of the present invention, taken along the direction a-a; fig. 8 is a partially enlarged schematic view of the structure of a portion B in the secondary battery 2 of fig. 7; fig. 9 is a schematic perspective view of a wiring board 501 in the secondary battery 2 of fig. 7 and 8; fig. 10 is a schematic perspective view of the wiring board 501 of fig. 9 in an exploded state. In the present embodiment, the same components as those in the wiring board 500 shown in fig. 5 and 6 described above are given the same reference numerals, and the same description will not be repeated. As shown in fig. 7 to 10, the wiring board 501 in the present embodiment also includes a main body portion 510 and an extended portion 520, the extended portion 520 is also a protrusion formed on the wing plate 512 of the main body portion 510, and the protrusion forms a recess on the side of the wing plate 512 facing away from the top cover plate 10.

However, in the present embodiment, the wiring board 501 is different from the wiring board 500 in the above-described embodiment in that the main body portion 510 and the extension portion 520 of the wiring board 501 are of a separate structure, that is, the extension portion 520 further includes the conductive block 530. That is, the extension 520 in this embodiment includes two parts, a protrusion formed on the body 510 in the same manner as in the above-described embodiment, and a conductive block 530 having a solid structure and overlapping the protrusion. By providing the conductive block 530, it is possible to facilitate copper-aluminum conversion between the terminal plate 21 and the first tab 310 (as a negative tab in this embodiment) in the terminal plate 21 when the terminal assembly 20 is a negative terminal assembly.

In order to increase the welding strength between the bus bar and the terminal plate 21 and between the terminal plate 31 and the bus bar, it is generally necessary to ensure that the terminal plate 21 and the portion where the terminal plate 31 and the bus bar are connected have the same base metal as the bus bar. Specifically, in the present embodiment, the material of the bus bar is, illustratively, aluminum, and since the material of the second tab 320 of the electrode assembly 300 is copper, the main body portion 510 of the terminal plate 501 connected to the first tab 310 is copper, while the protrusion integrally formed on the main body portion 510 is also copper.

In order to facilitate the welded connection between the protrusion using the copper material and the terminal plate 21 of the first electrode terminal using the aluminum material, a conductive block 530 using the copper material may be disposed between the protrusion and the terminal plate 21. Since the thickness of the conductive block 530 is thin and the terminal plate 21 has a small thickness, the terminal plate 21 and the conductive block 530, which are made of different base metals, may be first connected by ultrasonic welding or electromagnetic pulse welding. After the conductive block 530 is connected to the terminal plate 21, the extension 520 of the terminal plate 501 and the conductive block 530 using the same base metal may be welded by laser welding next. Therefore, copper-aluminum conversion can be performed between the terminal plate 21 and the first tab 310 through the terminal plate 501, so that the connection operation process between the terminal plate 501 and the terminal plate 21 and the first tab 310 is simplified, stronger connection strength can be achieved between the terminal plate 21 and the first tab 310, and the use reliability of the secondary battery is improved.

The manner of joining the terminal block 501 and the terminal plate 21 provided with the conductive block 530 is not limited to this. In other embodiments, the extension 520 of the terminal plate 501 may be formed by a protrusion having a base metal different from the material of the conductive block 530, and the material of the conductive block 530 may have the same base metal as the material of the terminal plate 21. At this time, the conductive block 530 and the bump are connected by ultrasonic welding or electromagnetic pulse welding; and the terminal plate 21 and the conductive block 530 having the same base metal are further welded by laser welding.

In an alternative embodiment, the surface of the terminal plate 21 on the side away from the top cover plate 10 is provided with a groove 21 a. Illustratively, for ease of arrangement, in the present embodiment, the groove 21a is a cylindrical groove. By providing the groove 21a on the terminal plate 21, the thickness of the terminal plate 21 can be reduced to facilitate the transmission of ultrasonic waves when the terminal plate 21 and the terminal plate 500 are welded using ultrasonic waves, so that ultrasonic welding can be performed at a small welding power; or when the laser welding terminal plate 21 and the terminal plate 500 are used, the laser welding is performed at a small welding power. In addition, since the terminal plate 21 needs to be connected to the bus bar through the surface away from the top cover plate 10, in the present embodiment, the terminal plate 21 is welded to the bus bar through the periphery of the groove 21 a. Since the bottom surface of the groove 21a is uneven after the terminal plate 21 and the terminal plate 500 are welded, the problem of cold joint occurring when the bus bar is welded to the terminal plate 21 can be avoided by connecting the bus bar to the outer periphery of the groove 21 a.

Since the outer peripheral surface of the terminal plate protrudes from the inner wall of the electrode lead-out hole 11, the terminal plate 20 is assembled from the top, and the terminal plate is fixed only by the fixing member 22 without separately providing another fixing structure on the terminal plate itself, thereby simplifying the structure of the terminal plate 21. Compared with the pole structure arranged on the top cover plate of the conventional secondary battery, the plate-shaped terminal plate 21 in the embodiment of the invention can be processed in batch by punching, so that the production efficiency can be improved, and the production cost can be reduced. Furthermore, the space inside the case 200 does not have to be occupied, and the energy density of the secondary battery 1 can be effectively increased.

Fig. 11 is a schematic sectional view of the secondary battery 1 of fig. 4 taken along section line B-B; fig. 12 is a partially enlarged schematic view of the structure of a portion C in the secondary battery 1 of fig. 11. As shown in fig. 1, 4, 11 and 12, according to an embodiment of the present invention, the connector for fixing the fixing member 22 includes a rivet 12, and the rivet 12 includes a nail body 121 and a stopper portion 122. The nail body 121 has one end connected to the upper surface of the top cover plate 10 (i.e., the surface of the top cover plate 10 facing away from the inside of the housing 200), and the other end connected to the position-limiting portion 122, and the cross-sectional area of the position-limiting portion 122 is larger than that of the nail body 121. Opposite side edges of the fixing member 22 extend outward to form extending edges, and at least one connecting hole 222 is provided on each extending edge, and the hole diameter of the connecting hole 222 is adapted to the size of the nail body 121 of the rivet 12 (as shown in fig. 1).

In a specific implementation, the rivet 12 may be used to secure the fastener 22 to the top cover plate 10 in several ways. In a specific example, the nail body 121 may be integrally provided on the top cover plate 10, after the nail body 121 passes through the connecting hole 222 provided on the fixing member 22, pressure is applied to an end portion of the nail body 121 far from the top cover plate 10 until the limiting portion 122 is formed at the end portion of the nail body 121, and the limiting portion 122 and a surface of the fixing member 22 far from the top cover plate 10 are abutted and matched with each other, so as to fix the fixing member 22 to the top cover plate 10.

In another specific example, the nail body 121 and the position-limiting portion 122 may be an integral structure, and the nail body 121 is provided with a threaded structure, and correspondingly, the top cover plate 10 is provided with a threaded hole matched with the threaded structure of the nail body 121, so that after the nail body 121 passes through the connecting hole 222 provided on the fixing member 22, the position-limiting portion 122 is in abutting fit with the surface of the fixing member 22 far away from the top cover plate 10, and the fixing member 22 is fixed on the top cover plate 10 by fastening the nail body 121 with the corresponding threaded hole provided on the top cover plate 10.

In addition, in another specific example, the fixing member 22 may be formed directly on the top cover plate 10 with the rivet 12 by integral injection molding, so that the rivet 12 can be directly wrapped inside the fixing member 22 and snap-fitted with the fixing member 22 to fix the fixing member 22 on the top cover plate 10. Moreover, the integral injection molding mode does not cause any damage to the structure of the fixing member 22.

In an alternative embodiment, the connector for securing the fastener 22 further comprises a first connector plate (not shown). Specifically, the first connecting plate is made of a metal material, and the first connecting plate includes a fitting portion and a contact portion connected to the fitting portion, wherein the contact portion has a prism-like structure, and a recess portion is formed at one side of the contact portion, and the fitting portion is a flange formed at an edge of the recess portion.

The opposite two extending edges of the fixing member 22 have notches, respectively, and the notches are provided with engaging grooves capable of receiving the engaging portions of the first connecting plate on the opposite two side walls thereof along the longitudinal direction, so that the engaging portions of the first connecting plate can be engaged in the engaging grooves of the notches, the contact portions of the first connecting plate are exposed from the notches, and the top cover plate 10 is contacted. In this way, the contact portion of the first connecting plate can be welded to the top lid plate 10, and the fastener can be fixed to the top lid plate 10 by the first connecting plate. By providing the recessed portion on the contact portion of the first connection plate, the lamination thickness of the contact portion and the top cover plate 10 can be reduced, so that the welded connection of the first connection plate and the top cover plate 10 is realized. In an alternative embodiment, the upper surface of the contact portion and the upper surface of the top cover plate are substantially flush, in which case butt welding may be used.

In addition, in the present embodiment, the lower insulating member 40 may be welded and connected to the side of the top cover plate 10 facing the inside of the housing by using a second connecting plate, for example. The specific connection of the lower insulating member 40 to the top cover plate 10 via the second connecting plate is the same as the connection of the fixing member 22 to the top cover plate 10 via the first connecting plate, and therefore, the detailed description thereof is omitted.

In an alternative embodiment, the connecting element may also be an inverted buckle integrally formed on the fixing element 22, and correspondingly, an inverted buckle hole (not shown) adapted to the inverted buckle is provided on the top cover plate 10. Specifically, a plurality of reversed holes may be disposed around the electrode lead-out hole 11, and the diameters of the reversed holes increase gradually along the direction from the fixing member 22 to the top cover plate 10, that is, the diameters of the reversed holes gradually decrease toward the opening direction along the bottom of the hole. Correspondingly, the surface of the fixing member 22 facing the top cover plate 10 is provided with an undercut capable of adapting to the shape of the undercut hole. Therefore, the fixing member 22 can be fixed to the top cover plate 10 by engaging the reverse buckle provided on the fixing member 22 with the reverse buckle hole provided on the top cover plate 10. Of course, the increasing is not required to increase the diameter of the reverse-buckling hole in the direction from the fixing member 22 to the top cover plate 10, but means that the diameter of the reverse-buckling hole at the end far away from the fixing member 22 is larger than the diameter of the reverse-buckling hole at the end near the fixing member 22, that is, the diameter of the reverse-buckling hole at the lower side is larger than the diameter of the reverse-buckling hole at the upper side.

Of course, the specific structure of the fixing member 22 in the embodiment of the present invention is not limited, and in other embodiments, when the terminal board 21 is circular or has another shape, the accommodating space of the fixing member 22 only needs to be set corresponding to the shape of the terminal board 21. In addition, a rivet 12 is provided on the side of the top cover plate 10 facing away from the fixing member 22, so that the top cover plate 10 can be connected to the lower insulating member 40 by the rivet 12 in a manner of being connected to the fixing member 22.

Of course, the specific shape of the sealing member is not limited in the embodiment of the present invention, and in other embodiments, the shape of the sealing member may be configured as a rectangle or other shape, and of course, the receiving groove on the top cover plate 10 needs to be configured to be suitable for the shape of the sealing member 23. In addition, in some embodiments, the fixing member 22 and the sealing member may be provided in an integrated manner, and of course, the material of the fixing member 22 needs to have both the sealing function and a certain hardness.

In an alternative embodiment, the terminal assembly 20 may further include an anti-rotation member, as shown in fig. 1 and 2, which is a stop 24 in this embodiment. Specifically, the terminal assembly 20 includes two stopper pieces 24 therein, and the two stopper pieces 24 have a cylindrical shape. Two first grooves (not shown) are formed on the surface of the terminal plate 21 facing the fixing member 22, two through holes are formed on the fixing member 22 corresponding to the first grooves, two second grooves 13 are formed on the surface of the top cover plate 10 facing the fixing member 22 opposite to the through holes, and two stopper blocks 24 are inserted into the two first grooves and the two second grooves 13, respectively, after passing through the two through holes of the fixing member 22.

Thus, two fixing points can be formed by the two stoppers 24 to position the terminal plate 21 and the fixing member 22 on the top deck 10, and the terminal plate 21 and the fixing member 22 are prevented from rotating relative to the top deck 10 along the surface of the top deck 10. Meanwhile, the terminal plate 21 and the fixing member 22 can be prevented from moving relative to each other, and therefore, the provision of the rotation preventing member can also ensure the coupling stability between the terminal plate 21 and the fixing member 22, and prevent the terminal plate 21 and the fixing member 22 from being separated from each other to affect the structural stability of the terminal assembly 20. Of course, embodiments of the present invention are not limited to the number of stops 24, and in other embodiments, the terminal assembly 20 may include more stops 24. Of course, in some embodiments, stopper 24 is a unitary structure with header plate 10, or stopper 24 is a unitary structure with terminal plate 21.

In the above-described embodiment, the body portion 510 and the extension portion 520 are of an integrated structure, but the embodiment of the present invention is not limited thereto. In other embodiments, the main body 510 and the extension 520 may be separate bodies, and in this case, the main body 510 and the extension 520 may be connected to each other by welding. In addition, in the above-described embodiment, the extension 520 is provided on the wing plate 512, thereby obtaining a more flexible coupling operation, but the embodiment of the present invention is not limited thereto, and in other embodiments, the extension 520 may be directly provided on the base plate 511. That is, the body 510 is formed in an integral plate-like structure.

In addition, as shown in fig. 12, the lower insulating member 40 may further include a nail body 421 and a position-limiting portion 422 (similar to the nail body 121 and the position-limiting portion 122 described above), and correspondingly, a second through hole 510a (shown in fig. 9) adapted to the diameter of the nail body 421 is provided on the wiring board 500, so that the nail body 421 can pass through the second through hole 510a on the wiring board 500, and abut against and engage with a surface of the wiring board 500 on a side away from the top cover plate 10 via the position-limiting portion 422, thereby fixing the lower insulating member 40 to the top cover plate 10 via the wiring board 500. The manner in which the lower insulator 40 and the wiring board 500 are joined to each other in this embodiment is the same as the manner in which the fixing member 22 is fixed to the top cover plate 10 by the rivet 12 in the above-described embodiment, and therefore, detailed description thereof will be omitted.

Fig. 13 is an enlarged view of the sealing member 23 of the cap assembly 100 of fig. 2 taken along an axial center plane. As shown in fig. 2, 4, 5 and 13, in particular, according to one embodiment of the present invention, a sealing member 23 is provided between the top cover plate 10 and the wiring board 500. The sealing member 23 has a ring-shaped structure in the present embodiment, and the sealing member 23 is disposed around the electrode lead-out hole 11. At least a part of the seal member 23 is in contact with the top lid plate 10 and the main body portion 510, respectively, and is compressed between the top lid plate 10 and the main body portion 510, and the surface of the seal member 23 on the side away from the terminal plate 21 does not exceed the surface of the lower insulating member 40 on the side away from the top lid plate 10. Therefore, the secondary battery 1 according to the embodiment of the present invention can reduce the occupation of the internal space of the case 200 by compressing the sealing member 23 between the top cap plate 10 and the terminal plate 500, thereby improving the energy density of the secondary battery 1 while preventing the electrolyte solution placed inside the case 200 from leaking from the electrode lead-out hole 11.

In an alternative embodiment, in particular, the seal 23 comprises: an axial extension 231, a radial extension 232, and an annular rim 233 (i.e., a first rim) formed at an outer circumferential surface of the radial extension 232. The axially extending portions 231 are respectively brought into close contact with the outer surface of the extending portion 520 of the terminal plate 500 and the inner surface of the electrode lead-out hole 11, and are pressed between the outer surface of the extending portion 520 and the inner surface of the electrode lead-out hole 11. And the radially extending portion 232 is in close contact with the surface of the top cover plate 10 facing the terminal block 500 and the surface of the body portion 510 facing the top cover plate 10, respectively, and is compressed between the body portion 510 and the top cover plate 10. Since the seal 23 is pressed in the axial direction and the radial direction, the sealing performance of the seal 23 at the electrode lead-out hole 11 can be further ensured, and the electrolyte inside the case 200 is prevented from leaking out of the electrode lead-out hole 11.

The annular rim 233 is compressed between the top cover plate 10 and the lower insulator 40 to further provide an axial pressing force to the sealing member 23 through the top cover plate 10 and the lower insulator 40, and the annular rim 233 is provided to configure the sealing member 23 to have a labyrinth-like sealing effect to further ensure the sealability at the electrode lead-out hole 11.

In addition, in an alternative embodiment, the fixing member 22 is further provided with an annular convex edge 223 (as shown in fig. 5 and 12, i.e., a second convex edge), and the outer diameter of the annular convex edge 223 is set in conformity with the diameter of the electrode lead-out hole 11. Thereby, the annular flange 223 can project into the electrode lead-out hole 11 and be brought into close contact with the top end face of the axial extension of the seal 23. So that the sealing member 23 can be simultaneously brought into close contact with the annular bead 223 of the fixing member 22, the top cover plate 10, the lower insulator 40, and the wiring board 500, thereby simultaneously providing a pressing force to the sealing member 23 through a plurality of structures to further improve the sealability of the sealing member 23.

In addition, in an alternative embodiment, a receiving groove (not shown in the drawings) is provided around the electrode lead-out hole 11 at a side surface of the top cap plate 10 away from the terminal plate 21, and may be, for example, a stepped groove. By placing the sealing element 23 in the receiving groove, the sealing element 23 is positively positioned so that undesired movement of the sealing element 23 relative to the top closure plate 10 is avoided. Meanwhile, the sealing element 23 can be subjected to balanced extrusion force, so that the space of the accommodating groove can be filled with the sealing element 23, and the sealing effect of the sealing element 23 can be further improved.

In addition, according to another embodiment of the present invention, there is also provided a battery module (not shown in the drawings) including the secondary battery according to any one of the above embodiments and a bus bar, wherein the bus bar is welded to the terminal plate 21, and the material of the bus bar has the same base metal as that of the terminal plate 21. Since the battery module includes the secondary battery in the above embodiment, it has the same advantages as the secondary battery, and thus, no further description is given.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Also, different features that are present in different embodiments may be combined to advantage. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art upon studying the drawings, the specification, and the claims.

Claims

1. A secondary battery, characterized by comprising:

a housing having an opening;

an electrode assembly accommodated in the case, including a first pole piece, a second pole piece, and a separator disposed between the first pole piece and the second pole piece;

a top cap assembly including a top cap plate covering the opening and having an electrode lead-out hole, and a first electrode terminal including a terminal plate located at one side of the top cap plate and covering the electrode lead-out hole;

a terminal plate including a main body portion and an extension portion connected to the main body portion, the main body portion being located on a side of the top cover plate away from the terminal plate and connected to the first pole piece, the extension portion extending into the electrode lead-out hole to be connected to the first electrode terminal, the main body portion and the extension portion being of an integrated structure, the extension portion including a protrusion disposed on a side of the main body portion close to the top cover plate, and a recess formed on a side of the main body portion away from the top cover plate by disposing the protrusion; and

a sealing member disposed between the top cover plate and the terminal plate and surrounding the extension portion to seal the electrode lead-out hole.

2. The secondary battery according to claim 1, wherein at least a portion of the seal member is in contact with and compressed between the top cap plate and the main body portion, respectively.

3. The secondary battery according to claim 1, wherein a material of the main body part and a material of the extension part have the same base metal, and a material of the extension part and a material of the first electrode terminal have different base metals.

4. The secondary battery according to claim 1, wherein the extension further includes conductive blocks welded with the projection and the terminal plate, respectively.

5. The secondary battery according to claim 4, wherein a material of the protrusion and a material of the conductive block have different base metals, and a material of the conductive block and a material of the first electrode terminal have the same base metal.

6. The secondary battery according to claim 1, wherein a surface of the terminal plate on a side away from the top lid plate is provided with a groove.

7. The secondary battery according to any one of claims 1 to 6, wherein the seal member is an annular structure, the seal member including an axially extending portion compressed between the extending portion and an inner wall of the electrode lead-out hole, and a radially extending portion compressed between the main body portion and a surface of the top lid plate remote from the terminal plate.

8. The secondary battery as claimed in claim 7, wherein the cap assembly further includes a lower insulating member disposed between the cap plate and the body part to maintain insulation between the cap plate and the terminal plate, and the lower insulating member has a first through-hole corresponding to the electrode lead-out hole.

9. The secondary battery according to claim 8, wherein the sealing member further comprises a first bead radially formed at an outer circumferential surface of the sealing member and compressed between the lower insulating member and the top cap plate.

10. The secondary battery according to claim 9, wherein the lower insulator is snap-connected to the wiring board.

11. The secondary battery according to claim 10, wherein the lower insulating member includes a nail body and a stopper portion connected to each other, the nail body is connected at one end to the stopper portion and is fixedly connected at the other end to the lower insulating member, the stopper portion has a cross-sectional area larger than that of the nail body, a second through hole is correspondingly provided in the terminal plate, the nail body passes through the second through hole, and the stopper portion abuts against a surface of the terminal plate on a side away from the top cap plate.

12. The secondary battery according to claim 9, further comprising a fixing member and a connecting member, the fixing member being fixed to the cap plate by the connecting member, an outer circumferential surface of the first electrode terminal being at least partially surrounded by the fixing member to fix the first electrode terminal to the fixing member.

13. The secondary battery as claimed in claim 12, wherein the fixing member further includes a second flange formed at a side of the fixing member facing the top cap plate and protruding into the electrode lead-out hole, and the sealing member is in close contact with the fixing member, the top cap plate, the lower insulating member, and the terminal plate at the same time.

14. The secondary battery according to claim 1, wherein a receiving groove surrounding the electrode lead-out hole is provided on a surface of the top cap plate on a side remote from the terminal plate, and the sealing member is received in the receiving groove.

15. A battery module, comprising:

a bus bar, and

the secondary battery according to any one of claims 1 to 14, wherein the bus bar is welded to the terminal plate, and the bus bar has the same base metal as that of the terminal plate.