WO2022110893A1

WO2022110893A1 - Cylindrical lithium battery

Info

Publication number: WO2022110893A1
Application number: PCT/CN2021/111310
Authority: WO
Inventors: 赵俊峰
Original assignee: 深圳市比克动力电池有限公司
Priority date: 2020-11-24
Filing date: 2021-08-06
Publication date: 2022-06-02
Also published as: CN214336854U

Abstract

The present application is applicable to the technical field of lithium batteries and provides a cylindrical lithium battery, comprising a battery housing, a battery cell assembly, a positive electrode end cover, and a negative electrode end cover. Two ends of the battery housing are respectively provided with openings; the battery cell assembly is provided in the battery housing; the positive electrode end cover and the negative electrode end cover are provided at the openings of the battery housing and are connected to the battery cell assembly; the positive electrode end cover comprises an explosion-proof piece, an insulator, and a connection piece; the insulator is provided between the explosion-proof piece and the connection piece; the explosion-proof piece comprises a connection part and a welding part; the connection part is arranged along the circumference of the welding part; and the welding part is welded to the connection part. According to the cylindrical lithium battery provided by the present application, welding is performed at a joint of the connection part and the welding part, such that the pressure when the explosion-proof piece is broken is accurately controlled, the accurate control of the breaking pressure of the explosion-proof piece is realized, it is ensured that the battery can form an exhaust channel in time, explosion of the battery is avoided, and the central part of the explosion-proof piece is separated from the connection piece when the internal pressure of the battery is too large; and the electric connection of a battery cap is broken, such that a battery short circuit is avoided.

Description

Cylindrical lithium battery

This application claims the priority of the Chinese Patent Application No. 202022755284.9 filed with the Chinese Patent Office on November 24, 2020, the entire contents of which are incorporated herein by reference.

technical field

The present application relates to the technical field of lithium batteries, and more particularly, to a cylindrical lithium battery.

Background technique

At present, the existing cylindrical battery with aluminum shell includes a battery shell. The battery shell is a cylindrical aluminum shell with an upward opening. The battery shell is designed with a battery cover plate fixing groove and a battery cell fixing groove. The battery shell is equipped with a battery cell. , the upper end of the battery cell is provided with the positive electrode ear and the negative electrode ear of the battery cell, the upper end of the battery case is covered with a battery cover plate, and the battery cover plate is inlaid with a conductive terminal, and the conductive terminal is fixed with the positive electrode ear and the negative electrode ear of the battery cell through the round hole. connect. However, the two ends of the existing cylindrical aluminum shell battery have a flat structure, the resistance value of the battery is relatively large when the battery is in use, and the pressure relief and exhaust channel cannot be formed in time, which is easy to cause thermal instability of the battery, and there is a risk of safe use of the battery.

technical problem

The purpose of the embodiments of the present application is to provide a cylindrical lithium battery, which aims to solve the problem that the two ends of the cylindrical aluminum shell battery in the prior art have a flat structure, the resistance value of the battery is relatively large during use, and the pressure relief exhaust channel cannot be formed in time, It is easy to cause thermal instability of the battery, and there is a technical problem of the risk of safe use of the battery.

technical solutions

In order to achieve the above purpose, the technical solution adopted in this application is: a cylindrical lithium battery is provided, comprising:

a battery case, two ends of the battery case are respectively provided with openings;

a cell assembly, the cell assembly is disposed in the battery housing;

a negative terminal cover, the negative terminal cover is arranged at the opening at one end of the battery case;

A positive terminal cover, the positive terminal cover is arranged at the opening at the other end of the battery case and connected to one end of the battery core assembly, and the positive terminal cover includes an explosion-proof disc, an isolation ring and a connecting piece , the isolation ring is arranged between the explosion-proof disc and the connection piece, the battery case is arranged on the outer circumferential direction of the explosion-proof disc, the explosion-proof disc includes a connection part and a welding part, and the isolation ring It is arranged at the bottom of the connecting portion, the connecting portion is arranged along the circumferential direction of the welding portion, and the welding portion is welded with the connecting portion.

Further, a rupture score line is provided on the welding part, and the rupture score line is arranged close to the connection part; and/or

The connecting piece is provided with a score line, and the score line is arranged near the connection between the middle part of the welding part and the middle part of the connecting piece.

Further, a groove is provided on a side of the connecting piece away from the welding portion, and the score line is located on the groove bottom of the groove.

Further, the thickness of the connecting part is greater than the thickness of the welding part, and the connecting part is provided with a bending part, the bending part is welded with the welding part, and the bending part is connected to the welding part. The welded part is enclosed to form a slot.

Further, an aluminum material layer is provided on the side of the negative electrode cover away from the battery core assembly, and a copper material layer is provided on the side of the negative electrode cover close to the battery core component. The material layer is connected to the other end of the battery core assembly.

Further, the negative terminal cover includes a cover plate and a connecting block, the cover plate is arranged on one end of the battery case, and a through hole is arranged on the cover plate, and the connecting block is arranged in the through hole Inside, the aluminum material layer is arranged on the side of the connection block away from the battery core assembly, the copper material layer is arranged on the side close to the battery core component, and the aluminum material layer is The edge and the edge of the copper material layer are respectively extended on the cover plate along the edge of the through hole in a direction away from the through hole.

Further, a liquid injection hole is provided on the cover plate; the cover plate further includes a sealing portion, the sealing portion is arranged in the liquid injection hole, and the sealing portion is used to block the liquid injection hole.

Further, the sealing portion is a stainless steel ball, and the stainless steel ball and the liquid injection hole are sealed by laser welding.

Further, the sealing portion and the liquid injection hole are bonded and sealed with an organic glue adhesive layer.

Further, the sealing portion is a T-shaped sealing nail, the liquid injection hole is a T-shaped hole matched with the T-shaped sealing nail, and the bottom edge of the T-shaped sealing nail is provided with a guide surface.

beneficial effect

The beneficial effect of the cylindrical lithium battery provided by the present application is that compared with the prior art, the cylindrical lithium battery of the present application is welded by the connection part of the explosion-proof disc and the connection part of the welding part, so that the explosion-proof disc can be controlled more accurately. The pressure at the time of breaking, thereby realizing the precise control of the rupture pressure of the rupture disk, ensuring that the battery can form an exhaust channel in time to prevent the battery from exploding. The electrical connection of the cover will not cause a short circuit of the battery, ensuring the safety of the battery and the safety of maintenance personnel.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for the present application. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic cross-sectional view of a cylindrical lithium battery provided by an embodiment of the present application;

Fig. 2 is the enlarged schematic diagram of A part in Fig. 1;

Fig. 3 is the enlarged schematic diagram of B part in Fig. 1;

4 is a schematic structural diagram of a negative end cap of a cylindrical lithium battery provided by an embodiment of the present application;

Fig. 5 is another structural schematic diagram of the negative end cap of the cylindrical lithium battery provided by an embodiment of the present application;

6 is another structural schematic diagram of the negative end cap of a cylindrical lithium battery provided by an embodiment of the present application;

FIG. 7 is a schematic diagram of a burst state of a positive end cap of a cylindrical lithium battery provided by an embodiment of the present application.

The details of the symbols involved in the above drawings are as follows:

1-Battery shell; 2-Cell assembly; 3-Positive terminal cover; 4-Negative terminal cover;

31-explosion-proof disc; 32-isolation ring; 33-connecting piece;

21-electrode roll core; 22-electrode extension sheet; 23-current collector plate;

311-connecting part; 312-welding part; 313-breaking score line; 314-bending part; 315-slotting;

331 - score line; 332 - groove;

41-connecting block; 42-cover plate; 43-sealing part; 44-sealing gasket;

411-aluminum material layer; 412-copper material layer;

421- injection hole;

431-Organic adhesive bonding layer; 432-T-type sealing nail.

Embodiments of the present invention

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

It is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" , "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the application and simplifying the description, rather than indicating or implying the indicated A device or element must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the present application.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

In order to illustrate the technical solutions described in the present application, a detailed description is given below with reference to the specific drawings and embodiments.

As shown in FIGS. 1 to 7 , an embodiment of the present application provides a cylindrical lithium battery, including a battery case 1 , a cell assembly 2 , a positive terminal cover 3 and a negative terminal cover 4 . The two ends are respectively provided with openings; the battery core assembly 2 is provided in the battery case 1; the negative terminal cover 4 is provided at the opening at one end of the battery case 1, and the positive terminal cover 3 is arranged at the opening at one end of the battery housing 1 and is connected to one end of the cell assembly 2. The positive end cover 3 includes an explosion-proof disc 31, an isolation ring 32 and a connecting piece 33. The The isolation ring 32 is arranged between the explosion-proof disc 31 and the connection piece 33 , and the battery case 1 is arranged outside the explosion-proof disc 31 ; the explosion-proof disc 31 includes a connection part 311 and a welding part 312 . The spacer 32 is disposed at the bottom of the connecting portion 311 , the connecting portion 311 is disposed along the circumferential direction of the welding portion 312 , and the welding portion 312 is welded with the connecting portion 311 .

In the cylindrical lithium battery provided by the embodiments of the present application, as shown in FIG. 1 and FIG. 2 , in addition, the connection part 311 of the explosion-proof disc 31 is welded with the connection part of the welding part 312 , which can control the rupture of the explosion-proof disc 31 more accurately. The pressure of the explosion-proof disc 31 can be accurately controlled to ensure that the battery can form an exhaust channel in time to prevent the battery from exploding. When the internal pressure of the battery is too large, the central part of the explosion-proof disc 31 is separated from the connecting piece 33, and the battery is disconnected. The electrical connection of the cap will not cause a short circuit of the battery, ensuring the safety of the battery and the safety of maintenance personnel.

It should be noted that the cell assembly 2 includes an electrode winding core 21 , an electrode extension sheet 22 and a current collector plate 34 . The electrode winding core 21 is arranged at the bottom of the current collector plate 34 . Material layer 412 is connected.

In some embodiments of the present application, optionally, as shown in FIG. 6 and FIG. 7 , a rupture score line 313 is provided on the welding portion 312 , and the rupture score line 313 is disposed close to the connection portion 311 ; and /or the connecting piece 33 is provided with a score line 331 , and the score line 331 is disposed near the connection between the middle portion of the welding portion 312 and the middle portion of the connecting piece 33 .

Optionally, as shown in FIGS. 3 and 7 , a groove 332 is provided on the side of the connecting piece 33 away from the welding portion 312 , and the score line 331 is located on the bottom of the groove 332 .

In this embodiment, the rupture score line 313 is set close to the connection part 311 . When the internal pressure of the battery is too large, the middle part of the welding part 312 is welded and contacted with the middle part of the connecting piece 33 , and the connecting piece 33 is formed on the middle part of the welding part 312 . The upward pressure is convenient for elastic deformation in the middle of the welding part 312, and then the rupture scribe line 313 close to the connecting part 311 is broken, which is convenient for decompression and air release. The score line 331 on the upper part is set close to the two ends of the connection between the connecting piece 33 and the welding part 312, so that when the internal pressure of the battery is too large, the scoring line 331 at the connecting piece 33 is disconnected first, and the electrical connection of the battery cap is completed. Disconnect, when the internal pressure of the battery continues to increase, the rupture score line 313 of the welding part 312 of the rupture disk 31 will be disconnected when the welding part of the connection part 311 of the rupture disk 31 and the welding part 312 is pulled and reaches the set welding pressure threshold. , an exhaust channel is formed, which is convenient for decompression and degassing. The score line 331 of the connecting piece 33 is located on the bottom of the groove 332, so that the groove faces the inside of the battery. When the internal pressure of the battery is too large, the scoring line at the connecting piece 33 The 331 is easier to disconnect, thereby completing the disconnection of the electrical connection of the battery cap.

In some embodiments of the present application, optionally, as shown in FIG. 3 and FIG. 7 , the thickness of the connecting portion 311 is greater than the thickness of the welding portion 312 , and the connecting portion 311 is provided with a bending portion 314 , the bending part 314 is welded with the welding part 312 , and the bending part 314 and the welding part 312 are enclosed to form a slot 315 .

In this embodiment, the bending portion 314 of the connecting portion 311 and the welding portion 312 are enclosed to form a slot 315, and a blasting area is formed at the slot 315, which increases the blasting space of the welding portion 312, facilitates pressure relief and exhausting, and at the same time , the connection between the welding part 312 and the connecting part 311 adopts ultrasonic welding or laser welding. In addition, the thickness of the connecting part 311 of the explosion-proof valve is greater than the thickness of the welding part 312, so that the thickness of the connecting part 311 is designed to ensure that the top cover is removed. The strength of the rear cap and the thickness of the welded portion 312 are designed to ensure that the rupture score line 313 on the explosion-proof valve can be broken in time to disconnect the electrical connection and ensure the safety of the battery.

In some embodiments of the present application, optionally, as shown in FIG. 2 , an aluminum material layer 411 is provided on the side of the negative terminal cover 4 away from the cell assembly 2 , and the negative terminal cover 4 is provided with an aluminum material layer 411 . A copper material layer 412 is disposed on the side close to the cell assembly 2 , and the copper material layer 412 is connected to the other end of the cell assembly 2 .

In this embodiment, an aluminum material layer 411 is provided on the side of the negative terminal cover 4 away from the cell assembly 2 , and a copper material layer is provided on the side of the negative terminal cover 4 close to the cell assembly 2 412, the copper material layer 412 is connected to the other end of the battery core assembly 2, so that when the battery is electrically connected to the outside of the battery through the aluminum material layer 411, the connection resistance is reduced, and the battery is electrically connected to the battery through the copper material layer 412. Connection resistance is also reduced when connecting.

In some embodiments of the present application, optionally, as shown in FIG. 2 , FIG. 4 to FIG. 6 , the negative terminal cover 4 includes a cover plate 42 and a connection block 41 , and the cover plate 42 is disposed on the battery One end of the housing 1, and the cover plate 42 is provided with a through hole, the connecting block 41 is disposed in the through hole, and the aluminum material layer 411 is disposed on the connecting block 41 away from the electrical On one side of the core assembly 2, the copper material layer 412 is disposed on the side close to the battery core assembly 2, and the edge of the aluminum material layer 411 and the edge of the copper material layer 412 are along the The edge of the through hole extends on the cover plate 42 in a direction away from the through hole. Optionally, a sealing gasket 44 is provided between the connection block 41 and the cover plate 42, and the sealing gasket 44 is used for sealing and insulation.

In this embodiment, specifically, the cover plate 42 is connected to the battery case 1 , the aluminum material layer 411 is disposed on the side of the connection block 41 away from the cell assembly 2 , and the copper material layer 412 is disposed close to the cell assembly On the side of The part 311 has an I-shaped structure, an aluminum material layer 411 is provided on the upper surface of the I-shaped shape, and a copper material layer 412 is provided on the lower surface of the I-shaped shape, so that the negative electrode cover plate 42 is electrically connected to the outside of the battery. The material layer 411 is connected to the outside of the battery, and the copper material layer 412 is connected to the cell assembly 2 inside the battery. Compared with the negative terminal cover 4 made of copper nickel-plated material in the prior art, the connection resistance is reduced.

In some embodiments of the present application, optionally, as shown in FIG. 2 , FIG. 4 to FIG. 6 , the cover plate 42 is provided with a liquid injection hole 421 ; the cover plate 42 further includes a sealing portion 43 , so The sealing portion 43 is disposed in the liquid injection hole 421 , and the sealing portion 43 is used to block the liquid injection hole 421 . Optionally, as shown in FIG. 3 , the sealing portion 43 is a stainless steel ball, and the stainless steel ball and the liquid injection hole 421 are sealed by laser welding.

In this embodiment, a liquid injection hole 421 is provided on the cover plate 42, and the sealing portion 43 is used to block the liquid injection hole 421. The sealing portion 43 can be a stainless steel ball, and the periphery of the stainless steel ball can be connected by laser welding or cold welding Seal, ensure the sealing of the stainless steel ball is stable, avoid shaking, and let the leakage stop.

In the above-mentioned embodiment of the present application, optionally, as shown in FIG. 5 , the sealing portion 43 and the liquid injection hole 421 are bonded and sealed by an organic glue adhesive layer 431 . It is also possible to use an organic adhesive bonding layer 431 on the upper end of the sealing ball to ensure the sealing stability of the sealing ball and avoid its shaking. The organic adhesive bonding layer 431 can be made of UV glue, etc.

In the above-mentioned embodiment of the present application, optionally, as shown in FIG. 6 , the sealing portion 43 is a T-shaped sealing nail 432 , and the liquid injection hole 421 is a T-shaped sealing nail 432 matched with the T-shaped sealing nail 432 . The bottom edge of the T-shaped sealing nail 432 is provided with a guide surface. The sealing ball can also be replaced by the T-shaped sealing nail 432, and the bottom of the T-shaped sealing nail 432 can be chamfered, that is, a guide surface is formed. packaging to prevent leakage.

To sum up, in the cylindrical lithium battery provided by the embodiments of the present application, an aluminum material layer is provided on the side of the negative terminal cover away from the cell assembly, and the side of the negative terminal cover close to the cell assembly is provided with an aluminum material layer. A copper material layer is provided, and the copper material layer is connected to the other end of the battery core assembly, so that when the battery is electrically connected to the outside of the battery through the aluminum material layer, the connection resistance is reduced, and the battery is connected to the inside of the battery through the copper material layer. The resistance is also reduced during the electrical connection. In addition, the connection part of the explosion-proof disc is welded with the connection part of the welding part, which can more accurately control the pressure when the explosion-proof disc is ruptured, thereby realizing the precise control of the rupture pressure of the explosion-proof disc and ensuring the battery It can form an exhaust channel in time to prevent the battery from exploding. When the internal pressure of the battery is too large, the explosion-proof disc can be broken in time, and the electrical connection of the battery cap can be disconnected, which will not cause a short circuit of the battery, ensuring the safety of the battery and the safety of maintenance personnel.

The above descriptions are only optional embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection of the present application. within the range.

Claims

A cylindrical lithium battery, comprising:

a battery case, two ends of the battery case are respectively provided with openings;

a cell assembly, the cell assembly is disposed in the battery housing;

a negative terminal cover, the negative terminal cover is arranged at the opening at one end of the battery case;

A positive terminal cover, the positive terminal cover is arranged at the opening at the other end of the battery case and connected to one end of the battery core assembly, and the positive terminal cover includes an explosion-proof disc, an isolation ring and a connecting piece , the isolation ring is arranged between the explosion-proof disc and the connection piece, the battery case is arranged on the outer circumferential direction of the explosion-proof disc, the explosion-proof disc includes a connection part and a welding part, and the isolation ring It is arranged at the bottom of the connecting portion, the connecting portion is arranged along the circumferential direction of the welding portion, and the welding portion is welded with the connecting portion.
The cylindrical lithium battery according to claim 1, wherein a rupture score line is provided on the welding part, and the rupture score line is arranged close to the connection part; and/or

The connecting piece is provided with a score line, and the score line is arranged near the connection between the middle part of the welding part and the middle part of the connecting piece.
The cylindrical lithium battery according to claim 2, wherein a groove is provided on the side of the connecting piece away from the welding portion, and the score line is located on the groove bottom of the groove.
The cylindrical lithium battery according to claim 1, wherein the thickness of the connecting part is greater than the thickness of the welding part, and the connecting part is provided with a bending part, and the bending part is connected to the welding part. The welding part is welded, and the bending part and the welding part are enclosed to form a slot.
The cylindrical lithium battery according to claim 1, wherein an aluminum material layer is provided on the side of the negative terminal cover away from the cell assembly, and the negative terminal cover is close to the cell assembly One side of the battery is provided with a copper material layer, and the copper material layer is connected to the other end of the battery core assembly.
The cylindrical lithium battery according to claim 5, wherein the negative terminal cover comprises a cover plate and a connecting block, the cover plate is arranged at one end of the battery case, and the cover plate is arranged with a cover plate and a connecting block. a through hole, the connecting block is disposed in the through hole, the aluminum material layer is disposed on the side of the connecting block away from the battery core assembly, and the copper material layer is disposed close to the electric On one side of the core component, the edge of the aluminum material layer and the edge of the copper material layer are respectively extended on the cover plate along the edge of the through hole in a direction away from the through hole.
The cylindrical lithium battery according to claim 6, wherein a liquid injection hole is provided on the cover plate;

The cover plate further includes a sealing portion, the sealing portion is disposed in the liquid injection hole, and the sealing portion is used to block the liquid injection hole.
The cylindrical lithium battery according to claim 7, wherein the sealing portion is a stainless steel ball, and the stainless steel ball and the liquid injection hole are sealed by laser welding.
The cylindrical lithium battery according to claim 7, wherein the sealing portion and the liquid injection hole are bonded and sealed with an organic glue adhesive layer.
The cylindrical lithium battery according to claim 7, wherein the sealing portion is a T-shaped sealing stud, the liquid injection hole is a T-shaped hole matched with the T-shaped sealing stud, and the T-shaped sealing stud The bottom edge of the type sealing nail is provided with a guide surface.