Cap assembly of battery and battery monomer

Abstract

The utility model discloses a cover cap assembly of a battery and a battery monomer, the cover cap assembly of the battery comprises a top cover, a first vent hole, a second vent hole and a cover cap, the anti-explosion piece is arranged on one side of the top cover in the thickness direction and connected with the top cover, and a second exhaust hole is formed in the anti-explosion piece; the welding piece is arranged on the side, away from the top cover, of the anti-explosion piece and connected with the anti-explosion piece, a third exhaust hole is formed in the welding piece, and the first exhaust hole, the second exhaust hole and the third exhaust hole are oppositely formed in the thickness direction of the top cover; the exhaust valve is arranged on the side, away from the anti-explosion piece, of the welding piece. And the elastic piece is connected with the exhaust valve. According to the cap assembly of the battery disclosed by the utility model, the pressure of the single battery can be released during formation, the internal pressure of the single battery is prevented from being too large, the safety of the single battery is improved, and meanwhile, the pressure of the single battery can be released regularly during use of the single battery, so that the safety of the battery is improved. And the safety and the service life of the battery monomer are further improved and prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cap assembly and a battery monomer. Background Art

[0002] In the prior art, during the production process, the cap is first sealed at the opening of the shell, and then the battery is formed. This will generate a certain amount of gas, which will be sealed in the shell, increasing the internal pressure of the battery and affecting the performance of the battery. At the same time, during use, the internal pressure of the battery will also increase. When the pressure increases to a certain value, the explosion-proof plate of the cap will rupture, and the battery will become invalid and scrapped. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a battery cap assembly, which can release pressure on the battery cell during formation to avoid excessive internal pressure of the battery cell, and can also achieve regular pressure relief operation on the battery cell, thereby improving the safety and service life of the battery cell.

[0004] The utility model also provides a battery monomer, comprising the battery cap assembly.

[0005] According to the cap assembly of the battery of the embodiment of the utility model, it includes: a top cover, the top cover is provided with a first exhaust hole; an explosion-proof plate, the explosion-proof plate is arranged on one side of the top cover in the thickness direction and is connected to the top cover, and the explosion-proof plate is provided with a second exhaust hole; a welding plate, the welding plate is arranged on the side of the explosion-proof plate away from the top cover and is connected to the explosion-proof plate, and the welding plate is provided with a third exhaust hole, in the thickness direction of the top cover, the first exhaust hole, the second exhaust hole and the third exhaust hole are arranged oppositely; an exhaust valve, the exhaust valve is arranged on the side of the welding plate away from the explosion-proof plate; an elastic member, the elastic member is connected to the exhaust valve, and is used to drive the exhaust valve to move toward the top cover to block the third exhaust hole.

[0006] According to the cap assembly of the battery of the embodiment of the utility model, the explosion-proof sheet is arranged on one side of the top cover in the thickness direction and connected to the top cover, the welding sheet is arranged on the side of the explosion-proof sheet away from the top cover and connected to the explosion-proof sheet, a third exhaust hole is arranged on the welding sheet, a second exhaust hole is arranged on the explosion-proof sheet and a first exhaust hole is arranged on the top cover, and in the thickness direction of the top cover, the first exhaust hole, the second exhaust hole and the third exhaust hole are arranged relatively to each other, and an exhaust valve is arranged on the side of the welding sheet away from the explosion-proof sheet; the elastic member is connected to the exhaust valve to drive the exhaust valve to move toward the top cover to block the third exhaust hole, so that the battery cell can be depressurized during formation to avoid excessive internal pressure of the battery cell, thereby improving the safety of the battery cell. At the same time, the battery cell can be depressurized regularly when in use, further improving the safety and service life of the battery cell.

[0007] In some embodiments of the present invention, one end of the elastic member is connected to the surface of the top cover facing the welding sheet, and the other end is penetrated through the second exhaust hole and the third exhaust hole and connected to the exhaust valve.

[0008] In some embodiments of the present invention, the center of the explosion-proof plate has a first protrusion protruding toward the welding plate, the center of the welding plate has a second protrusion protruding toward the explosion-proof plate, the first protrusion and the second protrusion are fitted and connected, the second exhaust hole is arranged on the first protrusion, and the third exhaust hole is arranged on the second protrusion.

[0009] In some embodiments of the present invention, the welding sheet has a vent hole, and the vent hole is arranged on the radial outside of the second protrusion. The explosion-proof sheet has a notch, and the notch is arranged on the radial outside of the first protrusion.

[0010] In some embodiments of the present invention, an insulating ring is provided between the explosion-proof plate and the welding plate, and the insulating ring is provided on a side of the notch away from the first protrusion.

[0011] In some embodiments of the present invention, the explosion-proof plate and the welding plate located between the insulating ring and the first protrusion are spaced apart to form an exhaust channel, and the exhaust channel is connected to the vent hole.

[0012] In some embodiments of the present invention, the center of the top cover has a third protrusion protruding away from the explosion-proof disk, and the first exhaust hole is provided on the third protrusion.

[0013] In some embodiments of the present invention, the cross-sectional shape of at least one of the first exhaust hole, the second exhaust hole, the third exhaust hole and the exhaust valve is circular or polygonal, and / or the cross-sectional shape of the exhaust valve is the same as the cross-sectional shape of the third exhaust hole.

[0014] In some embodiments of the utility model, the top cover is provided with a notch, and / or the welding sheet is provided with a notch.

[0015] A battery cell according to an embodiment of the present invention includes the above-mentioned battery cap assembly.

[0016] According to the battery cell of the embodiment of the utility model, by setting the cap assembly of the above-mentioned battery, the explosion-proof plate is arranged on one side of the top cover in the thickness direction and connected to the top cover, the welding plate is arranged on the side of the explosion-proof plate away from the top cover and connected to the explosion-proof plate, a third exhaust hole is arranged on the welding plate, a second exhaust hole is arranged on the explosion-proof plate and a first exhaust hole is arranged on the top cover, and in the thickness direction of the top cover, the first exhaust hole, the second exhaust hole and the third exhaust hole are arranged relatively, and an exhaust valve is arranged on the side of the welding plate away from the explosion-proof plate; the elastic member is connected to the exhaust valve to drive the exhaust valve to move toward the top cover to block the third exhaust hole, so that the battery cell can be depressurized during formation, avoiding excessive internal pressure of the battery cell, improving the safety of the battery cell, and at the same time, the battery cell can be depressurized regularly when in use, further improving the safety and service life of the battery cell.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 is a cross-sectional view of a cap assembly of a battery according to an embodiment of the utility model;

[0020] Figure 2 yes Figure 1 The enlarged view of point A in the middle;

[0021] Figure 3 is a top view of a cap assembly of a battery according to an embodiment of the utility model;

[0022] Figure 4 It is a bottom view of the cap assembly of the battery according to the embodiment of the utility model.

[0023] Reference numerals:

[0024] 10. Battery cap assembly;

[0025] 1. Top cover; 11. First exhaust hole; 12. Third protrusion;

[0026] 2. explosion-proof disk; 21. first protrusion; 22. second exhaust hole; 23. notch; 24. exhaust channel;

[0027] 3. welding sheet; 31. vent hole; 32. second protrusion; 33. third exhaust hole;

[0028] 4. Exhaust valve;

[0029] 5. Elastic parts;

[0030] 6. Insulation ring;

[0031] 7. Sealing ring. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0033] In the description of the present utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Reference below Figure 1-Figure 4 A cap assembly 10 of a battery according to an embodiment of the present invention is described.

[0036] like Figure 1-Figure 4 As shown, the cap assembly 10 of the battery according to the embodiment of the utility model comprises: a top cover 1, an explosion-proof plate 2, a welding plate 3, an exhaust valve 4 and an elastic member 5.

[0037] Specifically, refer to Figure 1 and Figure 2 A first exhaust hole 11 is provided on the top cover 1; an explosion-proof sheet 2 is provided on one side of the top cover 1 in the thickness direction and is connected to the top cover 1, and a second exhaust hole 22 is provided on the explosion-proof sheet 2; a welding sheet 3 is provided on the side of the explosion-proof sheet 2 away from the top cover 1 and is connected to the explosion-proof sheet 2, and a third exhaust hole 33 is provided on the welding sheet 3, and one end of the welding sheet 3 away from the explosion-proof sheet 2 is connected to the pole ear. Since the welding sheet 3 is connected to the explosion-proof sheet 2, and the explosion-proof sheet 2 is connected to the top cover 1, an electrical connection between the pole ear and the top cover 1 is achieved, so that the battery cell can work normally, wherein the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33 can be used for exhausting the battery cell, and can also facilitate the passage of the probe.

[0038] Furthermore, if Figure 1 and Figure 2 As shown, in the thickness direction of the top cover 1, the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33 are relatively arranged, that is, the axes of the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33 coincide, so as to facilitate the discharge of the gas inside the battery cell, improve the exhaust efficiency, thereby improving the safety of the battery cell, and also make it easier for the probe to pass through, making the operation simple.

[0039] Furthermore, if Figure 1 and Figure 2 As shown, the exhaust valve 4 is arranged on the side of the welding sheet 3 away from the explosion-proof sheet 2; the elastic member 5 is connected to the exhaust valve 4, and is used to drive the exhaust valve 4 to move toward the top cover 1 to block the third exhaust hole 33. The arrangement of the exhaust valve 4 and the elastic member 5 can block the third exhaust hole 33, ensure the sealing of the battery interior, and prevent the electrolyte from flowing to the outside, thereby improving the safety of the battery cell.

[0040] It is understandable that when the cap assembly of the battery is assembled, the interior of the battery cell is a sealed environment. At this time, the battery cell needs to be formed (i.e., the battery cell is charged with a small current) to activate the positive and negative electrode materials in the battery cell, so that the battery cell can work normally. However, when the battery cell is formed, gas will be generated inside the battery cell, and in the utility model:

[0041] When the battery cell is formed, the probe can be passed from the outside through the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33 in sequence to stop at the exhaust valve 4 and drive the exhaust valve 4 to move away from the explosion-proof plate 2, thereby opening the third exhaust hole 33, so that the gas generated during the formation operation of the battery cell can be discharged to the outside through the third exhaust hole 33, the second exhaust hole 22 and the first exhaust hole 11 in sequence, so that the pressure of the battery cell can be relieved during the formation, avoiding excessive internal pressure of the battery cell, and improving the safety of the battery cell. When the battery cell is formed, the elastic member 5 can drive the exhaust valve 4 to move toward the top cover 1 to re-block the third exhaust hole 33, thereby avoiding the outflow of electrolyte, improving the sealing of the battery cell, and further improving the safety of the battery cell.

[0042] In addition, when the battery cell is in use, the pressure relief operation can be performed regularly through the above operation to avoid excessive internal pressure in the battery cell causing the explosion-proof plate 2 to rupture and become ineffective, further improving the safety and service life of the battery cell.

[0043] The elastic member 5 may be a spring, a spring sheet or other elastic structural member. The formation operation of the battery cell is well known to those skilled in the art and will not be described in detail here.

[0044] Furthermore, if Figure 1 As shown, the battery cap assembly 10 also includes: a sealing ring 7, which is arranged around the top cover 1 and between the top cover 1 and the shell of the battery cell, so as to prevent the electrolyte from flowing out from the inside of the battery cell, improve the sealing of the battery cell, and further improve the safety of the battery cell.

[0045] According to the cap assembly 10 of the battery of the embodiment of the utility model, the explosion-proof plate 2 is arranged on one side of the top cover 1 in the thickness direction and connected to the top cover 1, the welding plate 3 is arranged on the side of the explosion-proof plate 2 away from the top cover 1 and connected to the explosion-proof plate 2, a third exhaust hole 33 is arranged on the welding plate 3, a second exhaust hole 22 is arranged on the explosion-proof plate 2 and a first exhaust hole 11 is arranged on the top cover 1, and in the thickness direction of the top cover 1, the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33 are arranged relatively, and an exhaust valve 4 is arranged on the side of the welding plate 3 away from the explosion-proof plate 2; the elastic member 5 is connected to the exhaust valve 4 to drive the exhaust valve 4 to move toward the top cover 1 to block the third exhaust hole 33, so that the battery cell can be depressurized during formation to avoid excessive internal pressure of the battery cell, thereby improving the safety of the battery cell. At the same time, the battery cell can be depressurized regularly when in use, further improving the safety and service life of the battery cell.

[0046] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, one end of the elastic member 5 is connected to the surface of the top cover 1 facing the welding sheet 3, and the other end is penetrated through the second exhaust hole 22 and the third exhaust hole 33 and connected to the exhaust valve 4. It can be understood that, through the above-mentioned connection method, the elastic member 5 is extended and arranged along the thickness direction of the top cover 1, wherein it should be noted that in the thickness direction of the top cover 1, the elastic member 5 is in a stretched state, so that the elastic member 5 has a tendency to contract, so that the elastic member 5 can drive the exhaust valve 4 to move toward the top cover 1 to re-block the third exhaust hole 33, improve the reliability of the exhaust valve 4 blocking the third exhaust hole 33, thereby further preventing the electrolyte from flowing to the outside, improving the sealing, and further improving the safety of the battery cell.

[0047] Furthermore, if Figure 1 and Figure 2 As shown, the axis of the elastic member 5 coincides with the axis of the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33, so that it is convenient for the probe to be simultaneously inserted into the first exhaust hole 11, the elastic member 5, the second exhaust hole 22 and the third exhaust hole 33, and it is also convenient for the elastic member 5 to be inserted into the second exhaust hole 22 and the third exhaust hole 33, and at the same time, the force on the elastic member 5 is also uniform, thereby further improving the reliability of the exhaust valve 4 blocking the third exhaust hole 33, thereby further preventing the electrolyte from flowing to the outside, improving the sealing, and further improving the safety of the battery cell.

[0048] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, the center of the explosion-proof plate 2 has a first protrusion 21 protruding toward the welding plate 3, and the center of the welding plate 3 has a second protrusion 32 protruding toward the explosion-proof plate 2. The first protrusion 21 and the second protrusion 32 are fitted and connected, the second exhaust hole 22 is provided on the first protrusion 21, and the third exhaust hole 33 is provided on the second protrusion 32.

[0049] It can be understood that the arrangement of the first protrusion 21 and the second protrusion 32 facilitates the connection between the welding plate 3 and the explosion-proof plate 2, and the second exhaust hole 22 is arranged on the first protrusion 21, and the third exhaust hole 33 is arranged on the second protrusion 32, thereby facilitating the relative arrangement of the second exhaust hole 22 and the third exhaust hole 33, thereby improving production efficiency.

[0050] In some embodiments of the present invention, Figure 2 and Figure 4 As shown, the welding plate 3 has a vent hole 31 , which is arranged radially outside the second protrusion 32 , and the explosion-proof plate 2 has a notch 23 , which is arranged radially outside the first protrusion 21 .

[0051] It can be understood that the notch 23 is arranged at one end of the explosion-proof plate 2 away from the welding plate 3 and is recessed toward the welding plate 3. Therefore, when gas is generated inside the battery cell and the gas pressure is too high, the gas can pass through the welding plate 3 from the vent 31. At this time, since the thickness of the notch 23 of the explosion-proof plate 2 is relatively small, the gas can break through the notch 23 and be discharged from the first exhaust hole 11, thereby preventing the internal gas pressure of the battery cell from being too high and causing an explosion, thereby improving the safety of the battery cell.

[0052] In addition, the connection between the explosion-proof plate 2 and the top cover 1 is located on the side of the notch 23 away from the first protrusion 21. Since the first protrusion 21 and the second protrusion 32 are connected, the welding plate 3 and the explosion-proof plate 2 are electrically connected, thereby realizing the electrical connection between the welding plate 3 and the top cover 1, so that the circuit of the battery cell can be connected. When gas is generated inside the battery cell and the gas pressure is too high, the gas can break through the notch 23. Since the notch 23 is arranged on the radially outer side of the first protrusion 21, the connection between the explosion-proof plate 2 and the top cover 1 is located on the side of the notch 23 away from the first protrusion 21, so that the electrical connection between the welding plate 3 and the top cover 1 is disconnected at this time, thereby disconnecting the circuit of the battery cell, thereby preventing the battery cell from continuing to work to generate gas and explode, thereby further improving the safety of the battery cell.

[0053] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, there is an insulating ring 6 between the explosion-proof plate 2 and the welding plate 3, and the insulating ring 6 is arranged on the side of the notch 23 away from the first protrusion 21. It can be understood that the insulating ring 6 can prevent the explosion-proof plate 2 and the welding plate 3 from contacting on the side away from the first protrusion 21 to achieve electrical connection, thereby, when the gas pressure inside the battery cell is too high and the gas breaks through the notch 23, the insulation between the welding plate 3 and the top cover 1 at this time is further guaranteed, thereby further ensuring the disconnection of the circuit of the battery cell, thereby preventing the battery cell from continuing to work and generating gas and exploding, thereby further improving the safety of the battery cell.

[0054] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, the explosion-proof plate 2 and the welding plate 3 located between the insulating ring 6 and the first protrusion 21 are arranged at intervals to form an exhaust channel 24, and the exhaust channel 24 is connected to the vent hole 31. Among them, the vent hole 31 is located between the insulating ring 6 and the second protrusion 32. The arrangement of the exhaust channel 24 can allow the exhaust channel 24 to accommodate a certain amount of gas, thereby preventing the battery monomer from breaking through the notch 23 as soon as the gas is generated, thereby improving the service life of the battery monomer.

[0055] In some embodiments of the present invention, Figure 1 and Figure 2As shown, the center of the top cover 1 has a third protrusion 12 protruding away from the explosion-proof plate 2, and the first exhaust hole 11 is provided on the third protrusion 12. It can be understood that the provision of the third protrusion 12 can provide a receiving space between the top cover 1 and the explosion-proof plate 2, so that it is convenient to install the elastic member 5. When the battery cell generates gas, due to the existence of the receiving space, the gas pressure can be prevented from rising too quickly, thereby further improving the safety of the battery cell.

[0056] In some embodiments of the present invention, the cross-section of at least one of the first exhaust hole 11, the second exhaust hole 22, the third exhaust hole 33 and the exhaust valve 4 is circular or polygonal, and / or the cross-section of the exhaust valve 4 is the same as the cross-section of the third exhaust hole 33. Thus, the reliability of the exhaust valve 4 in blocking the third exhaust hole 33 can be improved, thereby further preventing the electrolyte from flowing to the outside, improving the sealing, and further improving the safety of the battery cell.

[0057] In some embodiments of the present invention, Figure 3 As shown, a notch 23 is provided on the top cover 1. It can be understood that when the internal air pressure of the battery cell is too high and the first exhaust hole 11 cannot meet its exhaust demand, as the internal air pressure of the battery cell increases, the gas can break through the notch 23 on the top cover 1, so that the gas can be discharged faster, thereby further improving the safety of the battery cell.

[0058] Among them, Figure 3 As shown, the notches 23 on the top cover 1 are spaced apart along the circumferential direction of the top cover 1, thereby further promoting the rapid discharge of gas, thereby further improving the safety of the battery cell. In addition, since the notches 23 on the top cover 1 are spaced apart, when the notches 23 are broken, the top cover 1 will not fall off, further improving the safety of the battery cell. For example, Figure 3 In the example shown, there are two notches 23 on the top cover 1 spaced apart along the circumferential direction of the top cover 1, but the present invention is not limited thereto, and there may be more notches 23 on the top cover 1, such as 3, 4, 5 or 6.

[0059] and / or, if Figure 2 As shown, the welding sheet 3 is provided with a notch 23. Therefore, when the internal gas pressure of the battery cell is too high, as the internal gas pressure of the battery cell increases, the gas can break through the notch 23 provided on the welding sheet 3, so that the gas can be discharged faster, thereby further improving the safety of the battery cell.

[0060] A battery cell according to an embodiment of the present invention is described below.

[0061] The battery cell according to the embodiment of the present invention includes the battery cap assembly 10 described above.

[0062] According to the battery cell of the embodiment of the utility model, by setting the above-mentioned battery cap assembly 10, the explosion-proof plate 2 is arranged on one side of the top cover 1 in the thickness direction and connected to the top cover 1, the welding plate 3 is arranged on the side of the explosion-proof plate 2 away from the top cover 1 and connected to the explosion-proof plate 2, a third exhaust hole 33 is arranged on the welding plate 3, a second exhaust hole 22 is arranged on the explosion-proof plate 2 and a first exhaust hole 11 is arranged on the top cover 1, and in the thickness direction of the top cover 1, the first exhaust hole 11, the second exhaust hole 22 and the third exhaust hole 33 are arranged oppositely, and an exhaust valve 4 is arranged on the side of the welding plate 3 away from the explosion-proof plate 2; the elastic member 5 is connected to the exhaust valve 4 to drive the exhaust valve 4 to move toward the top cover 1 to block the third exhaust hole 33, so that the battery cell can be depressurized during formation, avoiding excessive internal pressure of the battery cell, improving the safety of the battery cell, and at the same time, the battery cell can be depressurized regularly when in use, further improving the safety and service life of the battery cell.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0064] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cap assembly, characterized in that: include: A top cover, wherein the top cover is provided with a first exhaust hole; An explosion-proof sheet, which is arranged on one side of the top cover in the thickness direction and connected to the top cover, and is provided with a second exhaust hole; A welding sheet, the welding sheet is arranged on a side of the explosion-proof sheet away from the top cover and connected to the explosion-proof sheet, the welding sheet is provided with a third exhaust hole, and in the thickness direction of the top cover, the first exhaust hole, the second exhaust hole and the third exhaust hole are arranged opposite to each other; An exhaust valve, the exhaust valve being arranged on a side of the welding sheet away from the explosion-proof sheet; An elastic member is connected to the exhaust valve and is used to drive the exhaust valve to move toward the top cover to block the third exhaust hole.

2. The battery cap assembly according to claim 1, characterized in that: One end of the elastic member is connected to the surface of the top cover facing the welding sheet, and the other end is penetrated through the second exhaust hole and the third exhaust hole and connected to the exhaust valve.

3. The battery cap assembly according to claim 1, characterized in that: The explosion-proof plate has a first protrusion protruding toward the welding plate at its center, and the welding plate has a second protrusion protruding toward the explosion-proof plate at its center. The first protrusion and the second protrusion are fitted and connected, the second exhaust hole is arranged on the first protrusion, and the third exhaust hole is arranged on the second protrusion.

4. The battery cap assembly according to claim 3, characterized in that: The welding sheet has a vent hole, and the vent hole is arranged on the radial outer side of the second protrusion. The explosion-proof sheet has a notch, and the notch is arranged on the radial outer side of the first protrusion.

5. The battery cap assembly according to claim 4, characterized in that: An insulating ring is provided between the explosion-proof plate and the welding plate, and the insulating ring is arranged on a side of the notch away from the first protrusion.

6. The battery cap assembly according to claim 5, characterized in that: The explosion-proof plate and the welding plate located between the insulating ring and the first protrusion are spaced apart to form an exhaust passage, and the exhaust passage is communicated with the vent hole.

7. The battery cap assembly according to claim 1, characterized in that: The center of the top cover has a third protrusion protruding away from the explosion-proof disk, and the first exhaust hole is arranged on the third protrusion.

8. The battery cap assembly according to claim 1, characterized in that: The cross-section of at least one of the first exhaust hole, the second exhaust hole, the third exhaust hole and the exhaust valve is circular or polygonal, and / or, The cross section of the exhaust valve is the same as the cross section of the third exhaust hole.

9. The battery cap assembly according to claim 1, characterized in that: The top cover is provided with notches, and / or the welding sheet is provided with notches.

10. A battery cell, characterized in that: A cap assembly comprising a battery according to any one of claims 1-9.

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