Cover plate, sealing assembly, battery cell, battery pack, electric equipment and welding device

Abstract

The cover plate comprises a first end face and a second end face which are oppositely arranged, the cover plate is provided with a liquid injection hole penetrating through the first end face and the second end face, the first end face is provided with a first groove, and the first groove is located in the periphery of the liquid injection hole. According to the battery cell, the liquid injection hole and the first groove are formed in the first end face of the cover plate, the liquid injection hole is used for injecting the electrolyte into the battery cell, and the first groove is located on the periphery of the liquid injection hole, so that the first groove can store the overflowed electrolyte after the electrolyte is injected into the liquid injection hole, and the situation that the electrolyte flows to the welding position of the cover plate and the sealing cover is reduced; and explosion during welding of the cover plate and the sealing cover is inhibited.

Description

Technical Field

[0001] The present application relates to the field of battery cell technology, and in particular to a cover plate, a sealing assembly, a battery cell, a battery pack, an electrical device and a welding device. Background Art

[0002] During the manufacturing process of the battery cell, electrolyte needs to be added from the injection hole on the top cover of the shell. The electrolyte provides a medium for the movement of ions between the positive and negative electrodes of the battery cell, thereby realizing the charging and discharging functions of the battery cell. After the injection process is completed, the injection hole cover is welded on the top cover of the shell to seal the injection hole and prevent leakage of the electrolyte.

[0003] In the prior art, electrolyte will remain around the injection hole when the battery cell is injected, and the shell top cover and the injection hole cover are connected by laser welding, which causes fire when the shell top cover and the injection hole cover are welded. Utility Model Content

[0004] The purpose of the present application is to provide a cover plate, a sealing assembly, a battery cell, a battery pack, an electrical device and a welding device to solve the problem of fire explosion when welding the cover plate and the sealing cover.

[0005] To achieve the purpose of this application, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides a cover plate, comprising a first end face and a second end face arranged opposite to each other, the cover plate being provided with an injection hole penetrating the first end face and the second end face, a first groove being provided on the first end face, and the first groove being located outside the injection hole.

[0007] In combination with the first aspect, in a possible implementation manner, the first groove is arranged around the liquid injection hole.

[0008] In combination with the first aspect, in a possible implementation manner, a second groove is provided on the first end surface, and the second groove is located outside the first groove and surrounds the first groove.

[0009] In combination with the first aspect, in a possible implementation, a first annular surface away from the second end face is provided between the first groove and the injection hole, a second annular surface away from the second end face is provided between the second groove and the first groove, and the first annular surface and the second annular surface have a height difference in the axial direction of the injection hole.

[0010] In a second aspect, the present application further provides a sealing assembly, comprising a sealing cover and a cover plate according to the first aspect, wherein the sealing cover is arranged on the first end surface, and the injection hole and the first groove are both located on the first end surface surrounded by the sealing cover.

[0011] In combination with the second aspect, in a possible implementation, a flange is protruding from the first end surface, the flange is located outside the injection hole and surrounds the injection hole, the first groove is located between the injection hole and the flange, and the sealing cover is connected to the flange.

[0012] In combination with the second aspect, in a possible implementation manner, the outer peripheral wall of the sealing cover is connected to the inner peripheral wall of the flange and a weld is formed.

[0013] In combination with the second aspect, in a possible implementation, the sealing cover includes a cover portion and a connecting portion, the connecting portion is connected to the cover portion and surrounds the cover portion, and one end of the connecting portion away from the cover portion is connected to the inner peripheral wall of the flange.

[0014] In combination with the second aspect, in a possible implementation manner, the connecting portion abuts against the first end surface, and a surface of the connecting portion away from the first end surface is flush with a surface of the flange away from the first end surface.

[0015] In combination with the second aspect, in a possible implementation manner, the orthographic projection of the first groove on the first end surface is located inside the orthographic projection of the connecting portion on the first end surface.

[0016] In combination with the second aspect, in a possible implementation, a second groove is further provided on the first end face, the first groove is provided around the injection hole, the second groove is located outside the first groove and surrounds the first groove, and the second groove is located between the first groove and the flange.

[0017] In a third aspect, the present application further provides a battery cell, comprising a shell and a cover plate according to the first aspect or a sealing assembly according to the second aspect, wherein the cover plate is connected to the shell and encloses a accommodating cavity, and the injection hole is connected to the accommodating cavity.

[0018] In a fourth aspect, the present application also provides a battery pack, comprising the battery cell according to the third aspect.

[0019] In a fifth aspect, the present application further provides an electrical device, comprising the battery cell according to the third aspect or the battery pack according to the fourth aspect.

[0020] In the sixth aspect, the present application also provides a welding device for welding the sealing assembly according to the second aspect, the welding device comprising an upper electrode and a lower electrode, the upper electrode being electrically connected to the lower electrode, the upper electrode abutting against the sealing cover, and the lower electrode abutting against the cover plate.

[0021] In combination with the sixth aspect, in a possible implementation manner, a flange is convexly provided on the first end surface, the flange is located outside the injection hole and surrounds the injection hole, and the first groove is located between the injection hole and the flange;

[0022] The sealing cover comprises a cover portion and a connecting portion, wherein the connecting portion is connected to the cover portion and surrounds the cover portion, and an end of the connecting portion away from the cover portion is connected to the inner peripheral wall of the flange;

[0023] The upper electrode is sleeved on the cover portion, and one end of the upper electrode abuts against a surface of the connecting portion away from the first end surface. The lower electrode is sleeved on an outer peripheral wall of the flange.

[0024] In combination with the sixth aspect, in a possible implementation manner, a cooling channel is provided in the upper electrode and / or the lower electrode.

[0025] In the present application, an injection hole and a first groove are provided on the first end face of the cover plate, the injection hole is used to inject electrolyte into the battery cell, and the first groove is located at the periphery of the injection hole, so that the first groove can store overflowed electrolyte after the electrolyte is injected into the injection hole; when the cover plate and the sealing cover are welded, the electrolyte flow to the welding position of the cover plate and the sealing cover is reduced, thereby suppressing fire when the cover plate and the sealing cover are welded. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic structural diagram of a sealing assembly according to an embodiment of the present application;

[0028] Figure 2 A top view of a cover plate according to an embodiment of the present application;

[0029] Figure 3 for Figure 2 BB cross-sectional view;

[0030] Figure 4 for Figure 1 AA section view;

[0031] Figure 5 A cross-sectional view showing the connection between a sealing assembly and a welding device according to an embodiment of the present application;

[0032] Figure 6This is a cross-sectional view of a sealing assembly and a welding device after explosion according to one embodiment of the present application.

[0033] Description of reference numerals:

[0034] 100, cover plate; 110, first end face; 120, second end face; 130, injection hole; 140, first groove; 141, first annular surface; 150, flange; 160, second groove; 161, second annular surface; 200, sealing cover; 210, cover part; 220, connecting part; 300, welding device; 310, upper electrode; 311, avoidance groove; 312, cooling channel; 320, lower electrode. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0037] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more of the related listed items.

[0038] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] The present application provides an electric device, which includes electric components and a battery pack, and the battery pack is used to power the electric components. Electric devices include mobile phones, tablet computers, sweepers and electric vehicles. The electric devices can be powered by built-in battery packs so that they can work without an external power supply. The battery pack can be a lithium-ion battery, a sodium-ion battery or a nickel-metal hydride battery. The battery pack includes a battery cell, a protective casing and a battery management system (BMS). The protective casing is used to accommodate the battery cell and protect the internal components of the battery from external impact and damage. The battery cell is the core part of the battery pack, containing positive and negative electrodes. It is the key to completing the storage and release of electrical energy in the battery pack. The battery cell can be a square laminated battery cell, a wound battery cell, etc., without restriction. The battery management system (BMS) is used to monitor and manage the working status of the battery, including the voltage, current, temperature and other parameters of the battery pack to ensure the safe and efficient operation of the battery.

[0040] The present application provides a battery cell, which includes a shell and a sealing assembly. The shell contains positive and negative electrodes and an electrolyte. The shell is made of metal or plastic and has a certain mechanical strength and corrosion resistance to protect the internal components of the battery cell from damage by the external environment. The electrolyte provides a medium for the movement of ions between the positive and negative electrodes of the battery, thereby realizing the charging and discharging functions of the battery. The sealing assembly is connected to the shell to ensure the sealing of the battery cell and prevent the electrolyte from leaking and external impurities from entering the battery cell. The sealing assembly includes a cover plate and a sealing cover. An injection hole for injecting electrolyte is provided on the cover plate. After the injection process is completed, the sealing cover is welded on the cover plate to seal the injection hole and prevent leakage of the electrolyte.

[0041] In the prior art, when the battery cell is injected with electrolyte, electrolyte will remain around the injection hole, causing fire when the cover plate and the sealing cover are welded.

[0042] See also Figure 1 , Figure 2 and Figure 3 In the sealing assembly provided in the present application, the sealing assembly includes a cover plate 100 and a sealing cover 200. The cover plate 100 is used to connect with the shell of the battery cell to form a receiving cavity capable of accommodating positive and negative electrodes. The cover plate 100 includes a first end face 110 and a second end face 120 arranged opposite to each other. The first end face 110 and the second end face 120 are located at both ends of the thickness direction of the cover plate 100. The first end face 110 is located outside the shell and on the side facing away from the positive and negative electrodes. The second end face 120 and the inner wall of the shell form a receiving cavity. An injection hole 130 is provided on the cover plate 100, which passes through the first end face 110 and the second end face 120. The injection hole 130 is connected to the receiving cavity so that the battery cell can inject electrolyte into the receiving cavity through the injection hole 130, providing a medium for ions to move between the positive and negative electrodes. The sealing cover 200 is connected to the cover plate 100 to cover the injection hole 130 after injection, so that the electrolyte is confined in the receiving cavity.

[0043] A first groove 140 and a flange 150 are provided on the first end surface 110 of the cover plate 100. The first groove 140 is located at the periphery of the injection hole 130, the flange 150 is located at the periphery of the injection hole 130 and surrounds the injection hole 130, and the first groove 140 is located between the injection hole 130 and the flange 150, and the flange 150 is used to connect with the sealing cover 200. By providing the first groove 140 between the flange 150 and the injection hole 130, the first groove 140 can store the overflowed electrolyte after the electrolyte is injected into the injection hole 130, reduce the electrolyte flow to the welding position of the cover plate 100 and the sealing cover 200, and suppress the explosion when the cover plate 100 and the sealing cover 200 are welded.

[0044] In the cover plate 100 provided in the present application, the first groove 140 may be an annular groove or a non-annular groove, without specific limitation. The opening direction of the first groove 140 is along the thickness direction of the cover plate 100 and is away from the shell of the battery cell. When the first groove 140 is an annular groove, the first groove 140 is arranged around the injection hole 130 to receive the electrolyte overflowing from the injection hole 130 in the circumferential direction of the injection hole 130, and further inhibit the electrolyte from flowing to the welding position between the cover plate 100 and the sealing cover 200. The first groove 140 may be a circular annular groove, a square annular groove, etc., without specific limitation.

[0045] The first groove 140 is formed by the first end surface 110 being recessed, and the shape of the first groove 140 may be circular, square, etc. When the shape of the injection hole 130 is circular, the injection hole 130, the first groove 140 and the flange 150 are sequentially arranged from inside to outside along the radial direction of the injection hole 130.

[0046] The flange 150 provided on the cover plate 100 can provide positioning for the installation of the sealing cover 200, which is beneficial to the assembly of the sealing cover 200. The outer peripheral wall of the sealing cover 200 is welded to the inner peripheral wall of the flange 150 to form an annular weld, thereby improving the connection strength and sealing performance between the cover plate 100 and the sealing cover 200.

[0047] In the sealing assembly provided in the present application, the sealing assembly also includes a sealing plug, which is inserted into the injection hole 130 to block the injection hole 130 after the battery cell is injected. The material of the sealing plug can be silicone, polyurethane (PU), polytetrafluoroethylene (PTFE), rubber, etc. The sealing cover 200 includes a cover portion 210 and a connecting portion 220, the connecting portion 220 is connected to the outer peripheral wall of the cover portion 210 and surrounds the cover portion 210, and the end of the connecting portion 220 away from the cover portion 210 is connected to the inner peripheral wall of the flange 150. Among them, the connecting portion 220 is convexly arranged on the outer wall of the cover portion 210 along the extension direction of the first end face 110, and the cover portion 210 protrudes from the first end face 110 so that the cover portion 210 can accommodate the sealing plug. And the setting of the first groove 140 can separate the sealing plug from the flange 150, which is conducive to suppressing the deformation or melting caused by direct heat of the sealing plug.

[0048] Specifically, the connection portion 220 abuts against the first end surface 110 to improve the stability of the connection between the sealing cover 200 and the cover plate 100. The surface of the connection portion 220 away from the first end surface 110 is flush with the surface of the flange 150 away from the first end surface 110, so that the flange 150 and the connection portion 220 form an edge welding effect, thereby better ensuring the airtightness and strength of the welding between the cover plate 100 and the sealing cover 200.

[0049] The orthographic projection of the first groove 140 on the first end surface 110 is located inside the orthographic projection of the connecting portion 220 on the first end surface 110, that is, the connecting portion 220 is not covered on the first groove 140 when it abuts against the first end surface 110, so as to increase the contact area between the connecting portion 220 and the first end surface 110 and improve the stability of the connection between the sealing cover 200 and the cover plate 100. At the same time, the connecting portion 220 of the sealing cover 200 is used for welding with the flange 150 of the cover plate 100, and the connecting portion 220 is not covered on the first groove 140, so as to further prevent the electrolyte from flowing to the welding position of the connecting portion 220 and the flange 150 and causing fire.

[0050] See also Figure 3 and Figure 4In the sealing assembly provided in the present application, a second groove 160 is further provided on the first end surface 110, the second groove 160 is located outside the first groove 140 and surrounds the first groove 140, and the second groove 160 is located between the first groove 140 and the flange 150. By providing the first groove 140 and the second groove 160 between the injection hole 130 and the flange 150, the first groove 140 and the second groove 160 can both store electrolyte, thereby forming multiple protections for the welding of the cover plate 100 and the sealing cover 200. Optionally, a first annular surface 141 away from the second end face 120 is provided between the first groove 140 and the injection hole 130, and a second annular surface 161 away from the second end face 120 is provided between the second groove 160 and the first groove 140. The first annular surface 141 and the second annular surface 161 have a height difference in the axial direction of the injection hole 130, that is, there is a height difference between the first groove 140 and the second groove 160 in the thickness direction of the cover plate 100, so that after the first groove 140 is filled with electrolyte, excess electrolyte can flow to the second groove 160 for storage, thereby storing more electrolyte.

[0051] See also Figure 5 and Figure 6 The present application provides a welding device 300 for welding a sealing assembly. The welding device 300 includes an upper electrode 310 and a lower electrode 320. The upper electrode 310 is electrically connected to the lower electrode 320. The upper electrode 310 abuts against the sealing cover 200, and the lower electrode 320 abuts against the cover plate 100. Specifically, when the sealing assembly is welded, the sealing cover 200 is pressed against the cover plate 100 by the upper electrode 310 to reduce the matching gap between the cover plate 100 and the sealing cover 200. After the welding device 300 is powered on, the upper electrode 310, the sealing cover 200, the cover plate 100 and the lower electrode 320 form a conductive path. Finally, under the action of the welding device 300, the welding of the cover plate 100 and the sealing cover 200 is completed to achieve the sealing between the cover plate 100 and the sealing cover 200.

[0052] In the welding device 300 provided in the present application, one end surface of the upper electrode 310 is recessed to form an avoidance groove 311, the upper electrode 310 is sleeved on the cover part 210, the cover part 210 is accommodated in the avoidance groove 311, and one end of the upper electrode 310 abuts on the surface of the connecting part 220 away from the first end surface 110, so as to press the connecting part 220 against the first end surface 110 of the cover plate 100. The lower electrode 320 is arranged in an annular shape, the lower electrode 320 is sleeved on the outer peripheral wall of the flange 150, and the lower electrode 320 abuts on the first end surface 110 of the cover plate 100 and the outer peripheral wall of the flange 150, and the flange 150 on the cover plate 100 is used to limit the installation of the lower electrode 320. After the welding device 300 is powered on, an annular weld is formed between the inner wall of the flange 150 and the outer wall of the connecting portion 220 at one time, thereby reducing welding steps, improving welding efficiency, reducing the manufacturing cost of the battery cell, and improving the welding yield of the sealing assembly.

[0053] The welding device 300 generates heat between the inner peripheral wall of the flange 150 and the outer peripheral wall of the connecting portion 220 through electric current to achieve welding of the flange 150 and the connecting portion 220. Specifically, the welding device 300 also includes a control component, which can synchronously control the power supply and pressurization, control each time period in the welding program, and adjust the welding current. By adjusting the size of the welding current of the welding device 300, the welding temperature can be accurately controlled, the heat accumulation between the flange 150 and the connecting portion 220 can be reduced, and the welding strength between the cover plate 100 and the sealing cover 200 can be improved. Optionally, a cooling channel 312 is provided in the upper electrode 310. When the welding device 300 welds the sealing assembly, a large amount of heat is generated when the current passes through the upper electrode 310, the sealing cover 200, the cover plate 100 and the lower electrode 320. By setting a cooling channel 312 in the upper electrode 310, the cooling water or coolant circulating in the cooling channel 312 can promptly take away the heat in the upper electrode 310, maintain the stability and life of the upper electrode 310, and thus improve the welding quality of the cover plate 100 and the sealing cover 200.

[0054] The welding process of the sealing component of the present application is as follows: the cover plate 100 is loaded, so that the lower electrode 320 of the welding device 300 is sleeved on the outer peripheral wall of the flange 150 and pressed against the outer peripheral wall of the flange 150 to realize the conduction of current; the sealing cover is loaded, and the CCD camera is used for positioning and identification, so that the outer peripheral wall of the sealing cover 200 is pressed against the inner peripheral wall of the flange 150; the upper electrode 310 of the welding device 300 is pressed downward, so that the upper electrode 310 and the sealing cover 200, and the sealing cover 200 and the cover plate 100 are pressed against each other to form a current conduction loop; the welding device 300 receives a trigger signal and starts working, the welding energy is applied, and a complete annular weld is formed between the inner peripheral wall of the flange 150 and the outer peripheral wall of the sealing cover 200.

[0055] The welding device 300 provided in the present application designs the upper electrode 310 and the lower electrode 320 into an annular structure, so that the welding energy transmission between the upper electrode 310 and the sealing cover 200 and between the lower electrode 320 and the outer peripheral wall of the flange 150 is uniform and consistent when they are in contact, thereby improving the consistency of the welding effect of the annular weld between the flange 150 and the sealing cover 200.

[0056] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0057] What is disclosed above is only a preferred embodiment of the present application, and it certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiment and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A cover plate, characterized in that: The cover plate includes a first end face and a second end face that are arranged opposite to each other. The cover plate is provided with a liquid injection hole that passes through the first end face and the second end face. A first groove is provided on the first end face. The first groove is located outside the liquid injection hole and is spaced apart from the liquid injection hole.

2. The cover plate according to claim 1, characterized in that: The first groove is arranged around the liquid injection hole.

3. The cover plate according to claim 2, characterized in that: A second groove is disposed on the first end surface, and the second groove is located at the periphery of the first groove and surrounds the first groove.

4. The cover plate according to claim 3, characterized in that: A first annular surface away from the second end surface is provided between the first groove and the injection hole, a second annular surface away from the second end surface is provided between the second groove and the first groove, and the first annular surface and the second annular surface have a height difference in the axial direction of the injection hole.

5. A sealing assembly, characterized in that: It comprises a sealing cover and a cover plate according to any one of claims 1 to 4, wherein the sealing cover is arranged on the first end surface, and the injection hole and the first groove are both located on the first end surface surrounded by the sealing cover.

6. The sealing assembly according to claim 5, characterized in that A flange is convexly arranged on the first end surface, the flange is located at the periphery of the injection hole and surrounds the injection hole, the first groove is located between the injection hole and the flange, and the sealing cover is connected to the flange.

7. The sealing assembly according to claim 6, characterized in that: The outer peripheral wall of the sealing cover is connected to the inner peripheral wall of the flange and a welding seam is formed.

8. The sealing assembly according to claim 6, characterized in that The sealing cover comprises a cover portion and a connecting portion, wherein the connecting portion is connected to the cover portion and surrounds the cover portion, and an end of the connecting portion away from the cover portion is connected to the inner peripheral wall of the flange.

9. The sealing assembly according to claim 8, characterized in that: The connecting portion is in contact with the first end surface, and a surface of the connecting portion away from the first end surface is flush with a surface of the flange away from the first end surface.

10. The sealing assembly according to claim 8, characterized in that The orthographic projection of the first groove on the first end surface is located inside the orthographic projection of the connecting portion on the first end surface.

11. The sealing assembly according to claim 6, characterized in that A second groove is also provided on the first end surface. The first groove is provided around the injection hole. The second groove is located outside the first groove and surrounds the first groove. The second groove is located between the first groove and the flange.

12. A battery cell, characterized in that: It comprises a shell and a cover plate according to any one of claims 1 to 4 or a sealing assembly according to any one of claims 5 to 11, wherein the cover plate is connected to the shell and encloses a receiving cavity, and the injection hole is connected to the receiving cavity.

13. A battery pack, characterized in that: Comprising the battery cell according to claim 12.

14. An electrical device, characterized in that: Comprising the battery cell according to claim 12 or the battery pack according to claim 13.

15. A welding device for welding the sealing assembly according to any one of claims 5 to 11, characterized in that: The welding device comprises an upper electrode and a lower electrode, wherein the upper electrode is electrically connected to the lower electrode, the upper electrode abuts against the sealing cover, and the lower electrode abuts against the cover plate.

16. The welding device according to claim 15, characterized in that A flange is convexly provided on the first end surface, the flange is located outside the injection hole and surrounds the injection hole, and the first groove is located between the injection hole and the flange; The sealing cover comprises a cover portion and a connecting portion, wherein the connecting portion is connected to the cover portion and surrounds the cover portion, and an end of the connecting portion away from the cover portion is connected to the inner peripheral wall of the flange; The upper electrode is sleeved on the cover portion, and one end of the upper electrode abuts against a surface of the connecting portion away from the first end surface. The lower electrode is sleeved on an outer peripheral wall of the flange.

17. The welding device according to claim 15, characterized in that A cooling channel is provided in the upper electrode and / or the lower electrode.

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