WO2019148662A1

WO2019148662A1 - Cap assembly of secondary battery, and secondary battery

Info

Publication number: WO2019148662A1
Application number: PCT/CN2018/083381
Authority: WO
Inventors: 张捷; 郭志君; 王鹏; 李国伟
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2018-02-01
Filing date: 2018-04-17
Publication date: 2019-08-08
Also published as: CN207800665U

Abstract

Provided are a cap assembly of a secondary battery, and a secondary battery. The cap assembly of the secondary battery comprises: a cap plate made of an insulating plastic material and having an electrode lead-out hole; an electrode terminal comprising a terminal plate positioned at one side of the cap plate and covering the electrode lead-out hole; and a current collecting connection member comprising a first connection portion and an extension portion connected to the first connection portion, the first connection portion being positioned at one side of the cap plate away from the terminal plate and bonded to the cap plate, and the extension portion extending into the electrode lead-out hole to be connected to the electrode terminal. The invention can facilitate efficient utilization of an internal space in a housing of a secondary battery, increase an energy density of the secondary battery, simplify a structure of an electrode terminal, and achieve one or more objectives relating to improvement of processing efficiency of a secondary battery.

Description

Secondary battery cover assembly and secondary battery

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. 20112018 068 3.7, filed on Jan. 2011.

Technical field

The present application relates to the field of power battery technologies, and in particular, to a top cover assembly for a secondary battery and a secondary battery.

Background technique

At present, the power battery generally adopts a square hard shell structure, and the power battery casing includes a casing and a top cover assembly. The power battery housing provides a sealed space for the electrode assembly and electrolyte. The electrical energy of the electrode assembly is led out of the confined space through the poles of the top cover assembly to the outside of the confined space. In the existing top cover assembly, the top cover is a metal plate and has a through hole, the pole is divided into a base portion and an extension portion, and the cross-sectional area of the base portion is larger than the aperture of the through hole. During assembly, the base portion is located below the top cover (ie, inside the housing), and the sealing ring is located between the base portion and the top cover. After the extension portion passes through the through hole, the extension portion is fixed by a circlip or by riveting. This method fixes the pole to the top cover.

Since it is necessary to fix the pole to the top cover, a part of the structure of the pole needs to be located inside the casing (usually 1.5 mm to 4 mm). The sealing ring is also located inside the casing, so that the space utilization inside the battery casing is low, resulting in low energy density of the battery. Moreover, in order to insulate the top cover from the electrode terminals disposed thereon, it is generally necessary to provide a corresponding insulating member between the pole and the top cover, thereby increasing the structural complexity of the top cover assembly and increasing The overall height of the top cover assembly results in low battery energy density.

Therefore, there is a need for a new secondary battery top cover assembly and secondary battery.

Summary of the invention

According to an embodiment of the present application, a cap assembly and a secondary battery of a secondary battery are provided, which can improve the space utilization ratio inside the secondary battery case, improve the energy density of the secondary battery, and simplify the structure of the electrode terminal. One or more of the effects of improving the processing efficiency of the secondary battery.

According to an aspect of the embodiments of the present application, a top cover assembly for a secondary battery includes: a top cover, the top cover is made of an insulating plastic and has an electrode lead-out hole; the electrode terminal includes an terminal block, The terminal board is located at one side of the top cover and covers the electrode lead-out hole; and a current collecting terminal board, the current collecting terminal board includes a first connecting portion and an extending portion connected to the first connecting portion, and the first connecting portion is located at the top cover A side facing away from the terminal block is attached to the top cover, and an extension portion extends into the electrode lead-out hole to be connected to the electrode terminal.

According to another aspect of an embodiment of the present application, there is also provided a secondary battery comprising: a housing having an opening; an electrode assembly housed in the housing, the electrode assembly having a body and a tab; and the cap assembly described above Covering the opening of the housing to enclose the electrode assembly in the housing, wherein the tab extends from a side of the body adjacent the top cover and is coupled to the current collecting terminal block.

In summary, the top cover assembly and the secondary battery of the secondary battery of the embodiment of the present application configure the current collecting terminal block located inside the housing to include a first connecting portion and an extending portion connected to the first connecting portion. The top cover is made of insulating plastic, and the first connecting portion of the collecting terminal plate is located on the side of the top cover facing the housing and is fitted to the top cover so as not to be between the top cover and the collecting terminal block. Additional insulation is added. The extension portion extends into the electrode lead-out hole and is connected to the electrode terminal disposed on the top cover plate, thereby achieving the purpose of electrically connecting the electrode assembly to the electrode terminal through the current collecting terminal plate, and the electrode terminal does not need to exceed the top cover The side of the panel faces the side of the housing. Therefore, the top cover assembly and the secondary battery of the embodiment of the present application have a structure that simplifies the electrode terminal, thereby improving the processing efficiency of the secondary battery, and further improving the space utilization ratio inside the secondary battery case, thereby improving the secondary battery. The advantage of energy density.

DRAWINGS

The present application can be better understood from the following description of the specific embodiments of the present application, in which:

Other features, objects, and advantages of the present invention will become more apparent from the description of the appended claims.

1 is a schematic exploded view of a secondary battery according to an embodiment of the present application;

2 is a schematic structural view of a top cover assembly in the secondary battery of FIG. 1;

Figure 3 is a cross-sectional structural view of the top cover assembly of Figure 2 taken along a longitudinal direction;

Figure 4 is an enlarged plan view showing a partial structure of a portion A of the top cover assembly of Figure 3;

FIG. 5 is a schematic structural view showing another mounted state of the secondary battery of FIG. 1; FIG.

6 is a schematic structural view of a top cover assembly according to another embodiment of the present application;

Figure 7 is an exploded perspective view of the top cover assembly of Figure 6;

Figure 8 is a cross-sectional structural view of the top cover assembly of Figure 6 taken along a longitudinal direction;

Figure 9 is an enlarged plan view showing a partial structure of a portion B of the top cover assembly of Figure 8;

10 is a cross-sectional structural view of a top cover assembly according to still another embodiment of the present application;

11 is a cross-sectional structural view of a top cover assembly according to still another embodiment of the present application.

Description of the reference signs:

1-secondary battery; 100-top cover assembly; 101-top cover assembly; 102-top cover assembly; 103-top cover assembly;

200-electrode assembly; 210-pole; 210a-bend;

10-top cover; 11-electrode extraction hole; 12-receiving groove; 13-stop flange;

20-first terminal assembly; 21-electrode terminal; 211-first terminal plate; 212-second terminal plate; 22-seal; 213-extension; 214-boom; 215-recess;

30-current collecting terminal block; 31-first connecting portion; 32-second connecting portion; 33-transition portion; 34-extension portion; 341-recess portion;

40-second terminal assembly; 41-electrode terminal; 42-seal.

Detailed ways

Features and exemplary embodiments of various aspects of the present application are described in detail below. In the following detailed description, numerous specific details are set forth However, it will be apparent to those skilled in the art that the present disclosure may be practiced without some of the details. The following description of the embodiments is merely provided to provide a better understanding of the present application. In the drawings and the following description, at least some of the structures and techniques are not shown in order to avoid unnecessary obscuring of the present application; and, for clarity, the dimensions of some of the structures may be exaggerated. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed description will be omitted. Furthermore, the features, structures, or characteristics described hereinafter may be combined in any suitable manner in one or more embodiments.

The orientation words appearing in the following description are all directions shown in the drawings, and are not intended to limit the specific structure of the top cover assembly and the secondary battery of the present application. In the description of the present application, it should also be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be, for example, a fixed connection or a Disassemble the connections, or connect them integrally; they can be connected directly or indirectly. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood as the case may be.

The secondary battery provided in the embodiment of the present application can perform charging and discharging operations cyclically to facilitate the multiple use of the secondary battery, and the secondary battery in the embodiment of the present application reduces the occupancy of the internal space of the housing. The energy density of the secondary battery can be improved, and the structure of the secondary battery is simple and easy to produce, so that the production efficiency of the secondary battery can be effectively improved, and the manufacturing cost thereof can be reduced.

For a better understanding of the present application, a top cover assembly and a secondary battery according to embodiments of the present application will be described in detail below with reference to FIGS. 1 through 11.

1 is a schematic exploded view of a secondary battery 1 according to an embodiment of the present application. FIG. 2 is a schematic structural view of a cap assembly 100 in the secondary battery 1 of FIG. 1. As shown in FIG. 1, the secondary battery 1 generally includes a top cover assembly 100, a housing (not shown), and an electrode assembly 200 located inside the housing.

According to one embodiment of the present application, the housing may be made of a plastic material such as PE or PP. The casing is formed in a rectangular box shape and has an opening to communicate the accommodation space inside thereof through the opening.

The electrode assembly 200 may be formed by stacking or winding a first pole piece, a second pole piece, and a separator together, wherein the separator is an insulator interposed between the first pole piece and the second pole piece. In the present embodiment, the first pole piece is exemplified as a positive electrode piece, and the second pole piece is a negative electrode piece. Similarly, in other embodiments, the first pole piece may also be a negative electrode sheet, and the second pole piece is a positive electrode sheet. Further, the positive electrode active material is coated on the coated portion of the positive electrode sheet, and the negative electrode active material is applied onto the coated portion of the negative electrode sheet. The uncoated region extending from the coated region of the body acts as a tab, and the electrode assembly 200 includes two tabs (only the tab 210 is shown in Figures 1 and 2), one of the two tabs It extends from the coated area of the positive electrode sheet; the other extends from the coated area of the negative electrode sheet.

The top cover assembly 100 is for sealing the housing, and the opening of the top cover assembly 100 to the housing can seal the electrode assembly 200 within the housing. Specifically, the electrode assembly 200 of the secondary battery 1 in the embodiment of the present application draws the positive electrode and the negative electrode to the outside of the secondary battery 1 from opposite directions, respectively. That is, the secondary battery 1 includes two top cover assemblies 100, and the two top cover assemblies 100 are respectively located on the upper and lower sides of the secondary battery 1. One of the terminal assembly and the negative terminal assembly for extracting the electric energy of the electrode assembly 200 to the positive electrode outside the secondary battery 1 is mounted on the top cover assembly 100 on the top of the secondary battery 1, and the positive terminal assembly and The other of the terminal assemblies of the negative electrode is mounted on the top cover assembly 100 at the bottom of the secondary battery 1.

Since the structures of the two top cover assemblies 100 located on both sides of the secondary battery 1 are completely the same, the structure of the top cover assembly 100 will be described below by taking only the top cover assembly 100 located on the upper side of the secondary battery 1 as an example. Of course, in other alternative embodiments, the structure of the cap assembly located on the upper and lower sides of the secondary battery may also be configured differently in accordance with the prior art.

3 is a cross-sectional structural view of the top cover assembly 100 of FIG. 2 taken along a longitudinal direction; and FIG. 4 is an enlarged partial view showing a portion A of the top cover assembly 100 of FIG. As shown in FIGS. 1 through 4, the top cover assembly 100 generally includes a top cover 10, a first terminal assembly 20, and a current collecting terminal block 30. The top cover 10 is in the form of a thin plate and has a size and shape that matches the opening of the housing so as to be connectable to the opening of the housing. The top cover 10 is made of insulating plastic, and the top cover 10 can be made of a high temperature resistant insulating plastic material, for example, one of polyphenylene sulfide PPS, perfluoroalkoxy resin PEA or polypropylene PP or Made in a variety of ways.

According to a specific example of the present application, the first terminal assembly 20 includes an electrode terminal 21 and a seal 22. In order to mount the first terminal assembly 20, the top cover 10 is provided with an electrode take-out hole 11.

The electrode terminal 21 includes a terminal plate which is a square thin plate-like structure, and the terminal plate is fixed on the side of the top cover 10 facing away from the electrode assembly 200, that is, from the top to the bottom when the first terminal assembly 20 is assembled. Way assembly. In an optional embodiment, the surface of the electrode terminal 21 near the top cover 10 does not exceed the surface of the top cover 10 close to the electrode terminal 21 (ie, the electrode terminal 21 only includes the terminal plate and does not protrude into the electrode lead-out hole. 11)). After the electrode terminal 21 is fixed to the top cover 10, the electrode terminal 21 covers the electrode lead-out hole 11 and the outer peripheral surface of the electrode terminal 21 protrudes from the inner wall of the electrode lead-out hole 11 (that is, as shown in FIGS. 3 and 4, the electrode terminal The cross-sectional dimension of 21 is larger than the cross-sectional dimension of the electrode lead-out hole 11).

Thereby, the electrode terminal 21 can be exposed inside the casing via the electrode lead-out hole 11 to be electrically connected to the electrode assembly 200, and the surface of the electrode terminal 21 facing away from the top cover 10 can be connected to the external bus bar. In one specific example, the electrode terminal 21 is an electrode terminal of a positive electrode (of course, the electrode terminal 21 may also be an electrode terminal of a negative electrode), which may be made of an aluminum or aluminum alloy material.

According to an embodiment of the present application, the current collecting terminal 30 is located between the electrode terminal 21 and the body of the electrode assembly 200. As a transition connecting member between the electrode terminal 21 and the tab 210, the current collecting terminal 30 is preferably used with an electrode. The terminal 21 and the tab 210 are made of the same metal material. The current collecting terminal block 30 includes a first connecting portion 31, a second connecting portion 32, and a transition portion 33, wherein the transition portion 33 is connected between the first connecting portion 31 and the second connecting portion 32 such that the current collecting terminal block 30 The whole is configured as a general C type. And in order to ensure the connection stability between the electrode terminal 21 and the tab 210, the first connecting portion 31, the second connecting portion 32, and the transition portion 33 are formed in an integrally formed manner.

According to a specific example of the present application, the first connecting portion 31 and the second connecting portion 32 are all in a flat plate shape, and both extend in the width direction of the top cover 10, in this embodiment, by way of example, A connecting portion 31 and a second connecting portion 32 are all parallel to the top cover 10, but the first connecting portion 31 and the second connecting portion 32 all extend along the width direction of the top cover 10, which does not mean that the two must be parallel The top cover 10 may extend substantially in the width direction of the top cover 10 as long as the first connecting portion 31 and the second connecting portion 32. That is, the first connecting portion 31 and the second connecting portion 32 may be slightly inclined with respect to the top cover 10.

Thereby, the first connection portion 31 of the current collecting terminal block 30 can be connected to the electrode terminal 21, and the second connection portion 32 can be connected to the tab 210.

In the actual connection process, when the electrode terminal 21 is connected to the tab 210 of the electrode assembly 200 through the current collecting terminal 30, the current collecting terminal plate 30 is first set as a substantially inverted L type (as shown in FIG. 1). Then, the first connecting portion 31 of the current collecting terminal 30 is soldered to the electrode terminal 21 for easy operation.

According to a specific example of the present application, in order to make the connection of the current collecting terminal 30 and the electrode terminal 21 more stable, and occupying as much space as possible inside the casing. The first connecting portion 31 includes a main body and an extending portion 34 connected to the main body, wherein the main body is located on a side of the top cover 10 facing the electrode assembly 200 for electrically connecting with the tab 210; and the extending portion 34 is capable of extending into the electrode lead-out hole 11 is electrically connected to the electrode terminal 21. Thereby, the electrode terminal 21 can be electrically connected to the corresponding pole piece in the electrode assembly 200.

In a specific example, the body of the first connecting portion 31 is configured as a flat sheet-like body, and the body is parallel to the top cover 10. Of course, the parallelism referred to herein is not strictly parallel, that is, in the specific implementation process, the parallelism of the main body and the top cover 10 is allowed to be inaccurate. According to an exemplary embodiment of the present application, since the top cover 10 is made of an insulating material, the first connecting portion 31 of the current collecting terminal 30 can be directly attached to the top cover 10 without being in the first connecting portion 31. An insulating member is provided between the top cover 10 and the top cover 10, so that the space occupied by the top cover assembly 100 can be reduced, and the energy density of the secondary battery 1 can be improved.

Illustratively, the extending portion 34 is a convex hull disposed on a surface of the main body of the first connecting portion 31 close to the top cover 10, and is formed on the surface of the main body away from the top cover 10 by providing the convex hull. Concave portion 341. That is, the convex hull includes a top wall and an annular side wall connected to the top wall such that the convex hull is open on the side of the main body away from the top cover 10. In an exemplary embodiment, when the body and the extension 34 are of unitary construction, the extension 34 may be a cylindrical convex hull formed on the body by stamping. Moreover, the integrally formed manner can enhance the structural strength of the current collecting terminal block 30 as a whole to increase the connection reliability between the electrode terminal 21 and the tab 210.

Thereby, the main body of the first connecting portion 31 can be directly attached to the surface of the top cover 10 facing the electrode assembly 200, and the extending portion 34 can be inserted into the electrode lead-out hole 11 to be in contact with the electrode terminal 21, thereby The extension portion 34 can be soldered to the electrode terminal 21, for example, by laser welding.

The extending portion 34 is formed by punching a convex hull on the first connecting portion 31, and the extending portion 34 can be inserted into the electrode drawing hole 11 to be electrically connected to the electrode terminal 21, so that the electrode terminal 21 does not need to face the electrode of the top cover 10. One side of the assembly 200 is additionally provided with another structure electrically connected to the first connecting portion 31. Therefore, the structure of the top cover assembly 100 can be simplified, and the space occupied by the top cover assembly 100 inside the casing can be reduced, so that the energy density of the secondary battery 1 can be effectively improved. In addition, since the structure and the processing of the electrode terminal 21 are simple and can be formed by a simple cutting and punching method, 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, by providing the recess 341 on the side of the first connecting portion 31 away from the top cover 10, more electrolyte can be stored in the housing, so that the cycle life of the battery can be increased (because the battery is charged and discharged) At the same time, in the charging and discharging of the secondary battery 1, gas is generated inside the casing, and the recess 341 can also accommodate a certain volume of gas, so that the casing can be prevented from being expanded and deformed to some extent.

According to an alternative embodiment of the present application, the convex hull is adapted to the shape of the electrode take-out hole 11, and the convex hull and the electrode lead-out hole 11 are both oblong or square in cross section. Therefore, when the convex hull is inserted through the electrode lead-out hole 11, the convex hull does not rotate circumferentially in the electrode lead-out hole 11 under the cooperation of the convex hull and the electrode lead-out hole 11, so that the convex set can be set. The flow terminal block 30 and the electrode terminal 21 connected to the current collecting terminal block 30 are limited. After the current collecting terminal block 30 and the electrode terminal 21 are rotated relative to the top cover 10, the connection stability between the current collecting terminal block 30 and the electrode terminal 21 is affected.

According to an alternative embodiment of the present application, a sinker portion is provided on a side of the top cover 10 remote from the electrode assembly 200, and the sinker portion surrounds the periphery of the electrode lead-out hole 11 and has a predetermined depth. The shape of the sinker portion is adapted to the shape of the electrode terminal 21. Since the electrode terminal 21 is a square plate body, the lower sink portion is correspondingly provided as a square groove. At least a portion of the electrode terminal 21 is housed in the sinker portion, that is, the electrode terminal 21 may be partially housed in the sinker portion, and the partial structure of the electrode terminal 21 is exposed to the outside to facilitate the electrode terminal 21 to be realized and converged. A welded connection between the rows.

Further, in order to secure the sealing property of the electrode lead-out hole 11, the sealing member 22 is provided between the electrode terminal 21 and the top cover 10. The sealing member 22 has an annular structure as a whole, and is interposed between the top cover 10 and the electrode terminal 21, and is in contact with the electrode terminal 21 and the top cover 10, respectively. Thereby, the sealing member 22 is in close contact with the top cover 10 and the electrode terminal 21, respectively, to seal the electrode lead-out hole 11, thereby ensuring the airtightness of the secondary battery 1.

In addition, in an optional embodiment, the top cover 10 is further provided with a receiving groove 12 around the electrode lead-out hole 11. The expanded area of the receiving groove 12 is smaller than the expanded area of the sinking portion, and the receiving groove 12 is deeper than the sinking portion. The depth of the portion is such that the accommodating groove 12 has a stepped structure around the electrode take-out hole 11. The seal 22 can be at least partially received in the receiving groove 12 to limit the seal 22 through the receiving groove 12, preventing the seal 22 from moving between the electrode terminal 21 and the top cover 10, and also reducing the top The overall thickness of the cover assembly 100 is increased, thereby increasing the energy density of the secondary battery 1.

In addition, according to an alternative embodiment of the present application, the top cover 10 is further provided with a stop flange 13 around the electrode lead-out hole 11, and the stop flange 13 matches the shape of the inner ring of the sealing member 22, In order to enable the seal 22 to fit over the stop flange 13 . Thereby, the sealing member 22 can be further positioned by the stopper flange 13 to ensure the sealing property of the electrode extraction opening 11. Furthermore, it is also possible to isolate the sealing member 22 from the extension 34 located in the electrode extraction opening 11 by providing the stop flange 13, so that the sealing member 22 can be prevented from being subjected to the welding connection between the electrode terminal 21 and the extension portion 34. The melting or deformation of the influence of the welding causes the sealing of the electrode lead-out hole 11 to fail, so that the reliability of use of the secondary battery 1 can be further improved.

Of course, the specific shape of the sealing member 22 is not limited in the embodiment of the present application. In other embodiments, the rotating body structure of the sealing member 22 may also be configured in a rectangular shape or other shapes. The receiving groove 12 on the 10 needs to be provided in accordance with the shape of the sealing member 22.

Fig. 5 is a schematic structural view showing another mounted state of the secondary battery 1 of Fig. 1. As shown in FIG. 5, one of the tabs 210 of the electrode assembly 200 generally includes a plurality of stacked sheets. For connection with the second connecting portion 32 of the current collecting terminal block 30, the thickness of the tab 210 relative to the top cover 10 is The bent portion 210a is formed by bending, and the bent portion 210a corresponds to a plate body extending in the width direction of the top cover 10.

Specifically, during the installation process, the current collecting terminal block 30 is connected to the tab 210 in an inverted L-shape, and the tab 210 is not yet bent relative to the body of the electrode assembly 200. That is, the second connecting portion 32 and the transition portion 33 are perpendicular to the first connecting portion 31 while the tab 210 extends toward the top cover 10. At this time, first, the tab 210 is attached to the second connecting portion 32 from the side close to the first connecting portion 31, and the second connecting portion 32 and the tab 210 which are bonded to each other are welded and connected by ultrasonic welding. Then, the current collecting terminal block 30 and the tab 210 can be bent. After being bent, the first connecting portion 31 and the second connecting portion 32 are parallel to each other and separated, so that the collecting terminal block 30 is configured as a substantially C. The bent portion 210a formed by the bending of the tab 210 is located between the first connecting portion 31 and the second connecting portion 32, and preferably the tab 210 is bent around the edge of the second connecting portion 32.

Thus, by providing the bent portion 210a between the first connecting portion 31 and the second connecting portion 32, on the one hand, the end portion of the tab 210 can be prevented from falling down in the direction of the electrode assembly 200 by gravity, and the electrode assembly can be made. The contact of the positive electrode tab and the negative electrode tab in the main body of 200 causes a short circuit, so that the safety and reliability of the secondary battery 1 can be improved. On the other hand, since the transition portion 33 is provided between the first connecting portion 31 and the second connecting portion 32, there is a gap between the first connecting portion 31 and the second connecting portion 32, so the bent portion 210a is set at the first Between the connecting portion 31 and the second connecting portion 32, the space between the first connecting portion 31 and the second connecting portion 32 can be further utilized to prevent the connection structure between the electrode terminal 21 and the tab 210 from occupying the inside of the secondary battery 1 Excessive space makes it possible to increase the energy density of the secondary battery 1.

In addition, by providing the transition portion 33 between the first connecting portion 31 and the second connecting portion 32, the electrode terminal 21 and the first connecting portion 31 can be connected by laser welding, and the second connecting portion 32 and the bending portion can be bent. The portion 210a is connected by ultrasonic welding, so that the connection between the electrode terminal 21 and the tab 210 can be simplified. At the same time, it is not necessary to provide a separate connecting plate body for the electrode terminal 21 inside the secondary battery 1, and it does not occupy too much internal space, so that the energy density of the secondary battery 1 can be improved. Further, when the secondary battery 1 is vibrated up and down during use, the transition portion 33 can absorb vibration to prevent the tab 210 from tearing due to non-deformation when the secondary battery 1 vibrates.

According to an alternative embodiment of the present application, the inner surface at the joint of the first joint portion 31 and the transition portion 33 is provided with a first score, and the inner surface of the joint portion of the second joint portion 32 and the transition portion 33 Set with a second score. Thereby, the current collecting terminal plate 30 can be more smoothly bent into a substantially C-shaped structure by the first notch and the second notch. Meanwhile, since the first notch and the second notch are located on the inner surface of the bent collecting terminal block 30, the bottom of the first notch and the second notch are subjected to compressive stress when the collecting terminal plate 30 is bent. Therefore, by providing the first notch and the second notch, it is possible to prevent the bottom of the notch from being subjected to tensile stress and causing the current collecting terminal plate 30 to be broken under the premise that the current collecting terminal plate 30 is smoothly bent.

Of course, the structure of the second terminal assembly 40 is similar to that of the first terminal assembly 20, and the second terminal assembly 40 also includes the electrode terminal 41 and the sealing member 42, and the electrode terminal 41 and the electrode terminal 21 are identical in structure and connection, and are sealed. The member 42 is identical in structure and connection to the seal 22 except that the second terminal assembly 40 is mounted on the opposite side of the first terminal assembly 20 by the cap assembly 100 located on the other side of the secondary battery 1.

6 is a schematic structural view of a top cover assembly 101 according to another embodiment of the present application; FIG. 7 is an exploded perspective view of the top cover assembly 101 of FIG. 6; and FIG. 8 is a longitudinal assembly of the top cover assembly 101 of FIGS. 6 and 7. FIG. 9 is an enlarged schematic view showing a partial structure of a portion B of the top cover assembly 101 of FIG. 8. FIG. For the sake of understanding, in the present embodiment, the same components as those of the top cover assembly 100 in the above embodiment are denoted by the same reference numerals, and the components that have been described in detail will not be described again. As shown in FIG. 6 to FIG. 9, in the present embodiment, the difference from the top cover assembly 100 in the above embodiment is that in the top cover assembly 101 of the present embodiment, the electrode terminal 21 includes the first terminal plate 211. And the second terminal block 212 to satisfy the switching between the external bus bar and the internal electrode assembly 200 by configuring the first terminal plate 211 and the second terminal plate 212 to have different base metals.

Specifically, in the embodiment, the electrode terminal 21 is a square thin plate-like structure including a first terminal plate 211 and a second terminal plate 212, and the first terminal plate 211 is located away from the top cover 10 of the second terminal plate 212. On one side, the second terminal block 212 covers the electrode lead-out hole 11. The first terminal plate 211 and the second terminal plate 212 are attached to each other, and the material of the first terminal plate 211 and the material of the second terminal plate 212 have different base metals (the main component metal constituting the alloy is called a base metal, such as iron In the carbon alloy, iron is a base metal. In an iron-nickel alloy having a nickel content of less than 50%, iron is a base metal, and in an iron-nickel alloy having a nickel content of more than 50%, nickel is a base metal).

In order to achieve laser welding between the electrode terminal 21 and the bus bar, the portion of the electrode terminal 21 connected to the bus bar needs to be made of the same base metal as the bus bar. Illustratively, when the electrode terminal 21 is the electrode terminal of the negative electrode and the material of the bus bar is aluminum, copper-aluminum conversion is required. Since the first terminal plate 211 is farther away from the top cover 10 than the second terminal plate 212, the first terminal plate 211 connected to the bus bar uses aluminum as the base metal, and the second terminal plate 212 connected to the negative electrode plate is used. Copper is used as the base metal. Since the material of the first terminal plate 211 is made of aluminum as the base metal, the material of the second terminal plate 212 is made of copper as the base metal. Thereby, by the recombination of the first terminal plate 211 and the second terminal plate 212, the welding strength between the electrode terminal 21 and the outer bus bar and the tab 210 of the electrode assembly 200 inside the casing can be improved.

In the present embodiment, the sealing member 22 for sealing the electrode take-out hole 11 surrounds the electrode lead-out hole 11 and is fitted between the second terminal plate 212 and the top cover 10, which can reduce the occupation of the internal space of the battery case. The energy density of the secondary battery is increased, and the probability that the sealing member 22 contacts the electrolyte inside the casing to cause swelling phenomenon is ensured, and the reliability of use of the secondary battery 1 is ensured. Meanwhile, since there is a potential difference between the first terminal plate 211 and the second terminal plate 212, if the electrolyte contacts the first terminal plate 211, the first terminal plate 211 is corroded, so the sealing member 22 surrounds the electrode extraction hole. 11 and being fitted between the second terminal plate 212 and the top cover 10 can prevent the electrolyte from corroding the first terminal plate 211, thereby improving the service life of the secondary battery 1.

In addition, for the electrode terminal 21 including two terminal plates having different base metals, the sealing member 22 is disposed between the top cover 10 and the electrode terminal 21, since the sealing member 22 is not in comparison with the existing top cover assembly There is no mutual pulling force between the two terminal plates, and instead, the pressure between the two terminal plates of the electrode terminal 21 can be provided by the sealing member 22 to each other. Therefore, it is possible to prevent the connection interface of the first terminal plate 211 and the second terminal plate 212 from being in a tensile stress state for a long period of time, thereby reducing the risk of breakage of the electrode terminal 21 and ensuring the reliability of use of the secondary battery 1.

FIG. 10 is a cross-sectional view of a top cover assembly 102 provided in accordance with yet another embodiment of the present application. As shown in FIG. 10, in the present embodiment, the same components as those in the top cover assembly 100 of the above-described embodiment are denoted by the same reference numerals, and the components that have been described in detail will not be described again. In the present embodiment, the top cover assembly 100 in the above embodiment is different in that the electrode terminal 21 of the top cover assembly 102 further includes an extension portion 213 disposed on the terminal plate of the electrode terminal 21 and is connected to the extension. The boss 214 of the portion 213 is connected to the extension portion 34 of the current collecting terminal 30 by the extending portion 213.

Specifically, in the present embodiment, it is preferable that the extending portion 213 and the boss 214 are integrally formed on the terminal block. The extension portion 213 is a cylindrical structure, and the area of the cross section of the terminal plate is larger than the area of the cross section of the extension portion 213. Further, the area of the cross section of the terminal plate is larger than the area of the cross section of the electrode extraction hole 11, and the area of the cross section of the extension portion 213 is smaller than the area of the cross section of the electrode extraction hole 11.

Therefore, when the electrode terminal 21 is assembled from the top to the bottom, the terminal plate is located on the side of the top cover 10 facing away from the electrode assembly 200, and the extending portion 213 is penetrated through the electrode lead-out hole 11 so that the terminal plate abuts against the top The cover plate 10 faces away from one side surface of the electrode assembly 200, thereby terminating the entire electrode terminal 21. That is, after the electrode terminal 21 is attached to the top cover 10, the outer peripheral surface of the terminal plate protrudes from the inner wall of the electrode lead-out hole 11. Thereby, the terminal plate serves as an external wiring portion to realize a connection with the bus bar; and the extension portion 213 serves as an inner wiring portion to realize connection with the tab 210 of the electrode assembly 200.

According to a specific example of the present application, in order to make the connection of the current collecting terminal 30 and the electrode terminal 21 more stable, the extending portion 34 is provided with a mounting hole, and correspondingly, the surface of the extending portion 213 of the electrode terminal 21 facing the electrode assembly 200 A boss 214 is provided, the cross-sectional area of the boss 214 is smaller than the cross-sectional area of the extension 213, and the shape of the boss 214 matches the shape of the mounting hole. Specifically, the mounting hole is disposed at a substantially intermediate position of the extending portion 34, and the boss 214 extends from the lower surface of the extending portion 213 (ie, the surface facing the electrode assembly 200) toward the electrode assembly 200 and protrudes into the mounting hole. And the lower surface of the extending portion 213 is in contact with the upper surface of the extending portion 34 (i.e., the surface facing away from the electrode assembly 200), whereby the extending portion 213 and the extending portion 34 can be weldedly connected.

Since the cross-sectional area of the boss 214 is smaller than the cross-sectional area of the extending portion 213, and the size of the mounting hole matches the size of the boss 214, when the electrode terminal 21 and the first connecting portion 31 are connected, the extending portion 213 is The extension portion 34 forms an abutment fit, so that the electrode terminal 21 can function as a mounting and positioning by the boss 214 during the actual assembly process. In addition, the welding operation of the extending portion 213 and the extending portion 34 is facilitated by the fitting of the mounting hole and the boss 214, so that the joint strength between the electrode terminal 21 and the current collecting terminal plate 30 can be improved.

According to an alternative embodiment of the present application, the shapes of the respective cross sections of the mounting holes and the bosses 214 may also be correspondingly arranged to be rounded or square, thereby preventing the relative occurrence between the electrode terminals 21 and the current collecting terminal plates 30. The purpose of the rotation is to improve the connection reliability between the electrode terminal 21 and the current collecting terminal block 30.

FIG. 11 is a cross-sectional structural view of a cap assembly 103 provided in accordance with yet another embodiment of the present application. As shown in Fig. 11, in the present embodiment, the same components as those of the above-described embodiment of the top cover assembly 103 are denoted by the same reference numerals, and the components that have been described in detail will not be described again. In the present embodiment, the top cover assembly 100 in the above embodiment is different in that the electrode terminal 21 of the top cover assembly 103 further includes an extension portion 213 provided on the terminal plate.

Specifically, in the present embodiment, it is preferable that the extending portion 213 is provided on the terminal plate in an integrally formed manner. And the area of the cross section of the terminal plate is larger than the area of the cross section of the extension portion 213, and the area of the cross section of the terminal plate is also larger than the area of the cross section of the electrode extraction hole 11, and the area of the cross section of the extension portion 213 is smaller than that of the electrode lead. The area of the cross section of the hole 11.

Therefore, when the electrode terminal 21 is assembled from the top to the bottom, the terminal plate is located on the side of the top cover 10 facing away from the electrode assembly 200, and the extending portion 213 is penetrated through the electrode lead-out hole 11 so that the terminal plate abuts against the top The cover plate 10 faces away from one side surface of the electrode assembly 200, thereby terminating the entire electrode terminal 21. That is, after the electrode terminal 21 is attached to the top cover 10, the outer peripheral surface of the terminal plate protrudes from the inner wall of the electrode lead-out hole 11. Thereby, the main body of the electrode terminal 21 serves as an external wiring portion to realize connection with the bus bar; and the extension portion 213 serves as an inner wiring portion to realize connection with the tab 210 of the electrode assembly 200.

In an alternative embodiment, the electrode terminal 21 forms a recess 215 on the side facing away from the electrode assembly 200 by providing the extension portion 213. For example, the electrode terminal 21 may be formed into a recess on the side facing the electrode assembly 200 by punching. 215. By forming the extending portion 213 and the recessed portion 215 on the terminal plate of the electrode terminal 21, the thickness of the electrode terminal 21 can be reduced, and laser welding can be realized at a small welding power when laser welding the electrode terminal 21 and the extending portion 34 are used; or Therefore, when ultrasonic welding of the electrode terminal 21 and the extending portion 34 is used, the ultrasonic transmission is more advantageous, so that ultrasonic welding can be realized with a small welding power.

The application can be embodied in other specific forms without departing from the spirit and essential characteristics. The present embodiments are to be considered in all respects as illustrative and not restrict All changes in the scope are thus included in the scope of the present application. Also, different technical features that appear in different embodiments can be combined to achieve a beneficial effect. Other variations of the disclosed embodiments can be understood and effected by those skilled in the <RTIgt;

Claims

A top cover assembly for a secondary battery, comprising:

a top cover, the top cover is made of insulating plastic and has an electrode lead-out hole;

An electrode terminal, the electrode terminal including a terminal plate, the terminal plate being located at one side of the top cover and covering the electrode extraction hole;

a current collecting terminal board including a first connecting portion and an extension connected to the first connecting portion, the first connecting portion being located at a side of the top cover facing away from the terminal plate And attaching to the top cover, the extending portion extends into the electrode lead-out hole and is connected to the electrode terminal.
The cap assembly according to claim 1, wherein the first connecting portion is in a sheet shape and extends in a width direction of the top cover, and the extending portion includes a proximity portion disposed at the first connecting portion a convex hull on one side of the top cover, the convex hull being connected to the electrode terminal.
The cap assembly according to claim 2, wherein the first connecting portion and the convex hull are of a unitary structure, and the first connecting portion is away from the top cover by forming the convex hull A recess is formed on one side of the plate.
The canopy assembly of claim 2, wherein the convex package has a cross-sectional shape that is oblong or square.
The cap assembly according to any one of claims 1 to 4, further comprising a seal disposed between the terminal plate and the top cover to seal the electrode lead-out hole .
The cap assembly according to claim 5, wherein said top cover further comprises an annular receiving groove and an annular stop flange located in said receiving groove, said receiving groove being led around said electrode a perimeter of the hole and located on a side of the top cover facing the terminal strip, and the stop flange continuously surrounds a circumference of the electrode lead-out hole, the seal being received in the receiving groove And fit outside the stop flange.
The cap assembly according to claim 5, wherein the terminal plate includes a first terminal plate and a second terminal plate connected to the first terminal plate, the first terminal plate being located at the second terminal plate a side away from the top cover, the second terminal plate covers the electrode extraction hole, and the material of the first terminal plate and the material of the second terminal plate have different base metals, A seal is disposed between the second terminal plate and the top cover.
A secondary battery, comprising:

a housing having an opening;

An electrode assembly housed in the housing, the electrode assembly having a body and a tab; and a cap assembly according to any one of claims 1 to 7 covering an opening of the housing to The electrode assembly is enclosed in the housing,

Wherein the tab extends from a side of the body adjacent to the top cover and is connected to the current collecting terminal.
The secondary battery according to claim 8, wherein the current collecting terminal further includes a second connecting portion and a transition portion, the first connecting portion and the second connecting portion being along the top cover The width direction extends and is disposed opposite to each other by the transition portion, and the tab is bent with respect to a thickness direction of the top cover to form a bent portion, and the second connecting portion is coupled to the bent portion.
The secondary battery according to claim 9, wherein the tab is bent around an edge of the second connecting portion, and the bent portion is located at the first connecting portion and the second connecting portion between.
The secondary battery according to claim 9, wherein the first connecting portion, the transition portion, and the second connecting portion are of a unitary structure.
The secondary battery according to claim 11, wherein an inner surface of a joint portion of the first connecting portion and the transition portion is provided with a first score; and/or

The inner surface of the joint portion of the second connecting portion and the transition portion is provided with a second score.