Pressure relief assembly of single battery and battery

Abstract

The utility model provides a pressure relief assembly of a battery monomer and a battery, and belongs to the technical field of batteries. The pressure relief assembly of the single battery comprises a cover plate, an anti-explosion piece and an opening and closing valve, the cover plate is provided with a first surface and a second surface which are opposite in the first direction, and the cover plate is provided with an anti-explosion hole penetrating through the first surface and the second surface; the anti-explosion piece covers the anti-explosion hole; the opening and closing valve is installed on the second surface, and the opening and closing valve and the anti-explosion piece define a closed pressure relief space. And when the gas in the single battery body applies pressure to the opening and closing valve and the pressure reaches a certain threshold value, the opening and closing valve forms a pressure relief channel, and the gas enters the pressure relief space. Through the arrangement of the opening and closing valve, a barrier can be formed between the anti-explosion sheet and the electrolyte, so that the electrolyte is prevented from being in direct contact with the anti-explosion sheet, the time for preventing the anti-explosion sheet from being corroded is prolonged, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a pressure relief assembly of a battery cell and a battery. Background Art

[0002] Lithium batteries are widely used in electric vehicles, backup power systems, and microgrid energy storage systems due to their high energy density and long life.

[0003] The existing explosion-proof valve is on the shortest path of ion transmission. Due to its relatively small thickness design size, it is easy to come into contact with the electrolyte leaked from the battery cell in a short time, causing the explosion-proof valve to be corroded by the electrolyte, seriously affecting the service life of the explosion-proof valve and the battery. Utility Model Content

[0004] In view of this, the purpose of the present application is to overcome the deficiencies in the prior art and provide a pressure relief assembly cover for a battery cell and a battery.

[0005] In a first aspect, an embodiment of the present application provides a pressure relief assembly for a battery cell, comprising:

[0006] The cover plate has a first surface and a second surface that are opposite to each other along a first direction, and the cover plate is provided with an explosion-proof hole that passes through the first surface and the second surface;

[0007] Explosion-proof disks, covering explosion-proof holes; and

[0008] An opening and closing valve is installed on the second surface, and the opening and closing valve and the explosion-proof disk are combined to form a closed pressure relief space;

[0009] When the gas in the battery cell applies pressure to the opening and closing valve and reaches a certain threshold, the opening and closing valve forms a pressure relief channel, allowing the gas to enter the pressure relief space.

[0010] In some embodiments, the inner wall of the explosion-proof hole protrudes into the inside of the explosion-proof hole to form a step portion, the step portion extends along the circumference of the explosion-proof hole to be closed, and the edge area of ​​the explosion-proof plate is fixed on the step portion.

[0011] In some embodiments, the opening and closing valve includes a protective cover and a valve plate, the outer edge of the protective cover is fixed on the cover plate, and the valve plate is assembled on the protective cover; when the gas applies pressure to the valve plate and reaches a certain threshold, the valve plate moves in a direction toward the second surface to form a pressure relief channel between the protective cover and the valve plate.

[0012] In some embodiments, the maximum distance that the valve plate moves in the direction toward the second surface is S1, and the minimum distance between the end of the valve plate close to the cover plate and the second surface is S2, wherein S2>S1>0.

[0013] In some embodiments, the protective cover includes a connecting ring and a first guide ring. The connecting ring is located in the outer peripheral area of ​​the explosion-proof hole. One end of the first guide ring is connected to the connecting ring, and the other end extends obliquely in a direction away from the second surface to form a mounting hole. The valve plate closes the mounting hole, and a pressure relief channel is formed between the first guide ring and the valve plate.

[0014] In some embodiments, the valve plate includes a second guide ring and a sealing portion. The second guide ring is inclined in a direction away from the second surface and is in contact with the first guide ring. The sealing portion is connected to the edge of the second guide ring to close the pressure relief space.

[0015] In some embodiments, the side of the first guide ring facing the explosion-proof disk is a concave surface, and the side of the second guide ring facing the protective cover is provided with a convex surface, and the convex surface is partially fitted with the concave surface.

[0016] In some embodiments, the valve plate includes at least one stopper on a side facing away from the explosion-proof plate, the stopper has a slot, and the slot is engaged with an edge area of ​​the protective cover away from the cover plate to fix the valve plate on the protective cover.

[0017] In some embodiments, the limiting member includes an extension portion and a limiting portion; one end of the extension portion is fixedly connected to the blocking portion, and the other end passes through the mounting hole and is connected to the limiting portion to form a slot.

[0018] In a second aspect, some embodiments of the present application provide a battery, including a shell, an electrode assembly and the pressure relief assembly of the above-mentioned battery cell, wherein the shell has at least one opening along a first direction, and a cover plate closes the opening.

[0019] The embodiments of the present application have the following advantages: by setting the opening and closing valve, a barrier can be formed between the explosion-proof plate and the electrolyte to prevent the electrolyte from directly contacting the explosion-proof plate, thereby extending the time that the explosion-proof plate is not corroded and improving the service life of the battery; if the air pressure in the pressure relief space is lower than the air pressure on the side of the opening and closing valve away from the explosion-proof plate, the gas can reach the explosion-proof plate through the air pressure opening and closing valve, and be discharged normally when the pressure reaches the set value, thereby realizing the explosion-proof effect of the battery cover.

[0020] In order to make the above-mentioned objects, features and advantages of the present application more obvious and understandable, preferred embodiments are given below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic structural diagram of a pressure relief assembly of a battery cell provided in some embodiments of the present application;

[0023] Figure 2 for Figure 1 A cross-sectional view of the battery cover AA shown in FIG.

[0024] Figure 3 for Figure 1 A cross-sectional view of the battery cover BB shown in FIG.

[0025] Figure 4 for Figure 2 An enlarged view of section C shown in;

[0026] Figure 5 An exploded view of the structure of a pressure relief assembly of a battery cell provided in some embodiments of the present application;

[0027] Figure 6 Schematic diagram of the structure of the opening and closing valve provided in some embodiments of the present application Figure 1 ;

[0028] Figure 7 An exploded view of the structure of an on-off valve provided in some embodiments of the present application;

[0029] Figure 8 Schematic diagram of the structure of the opening and closing valve provided in some embodiments of the present application Figure 2 ;

[0030] Fig. 9 for Figure 8 A cross-sectional view of the DD portion is shown in FIG.

[0031] icon:

[0032] 100-cover plate; 110-explosion-proof hole; 120-step portion; 130-first surface; 140-second surface; 200-explosion-proof plate; 300-opening and closing valve; 310-protective cover; 311-mounting hole; 312-first guide ring; 312a-concave surface; 313-connecting ring; 320-valve plate; 321-sealing portion; 322-second guide ring; 322a-convex surface; 400-pressure relief space; 500-limiting member; 510-extension portion; 520-limiting portion; 530-slot. DETAILED DESCRIPTION

[0033] The embodiments of the present application 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 application, and cannot be understood as limiting the present application.

[0034] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0035] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

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

[0038] Reference Figures 1 to 9 , the embodiment of the present application provides a pressure relief assembly for a battery cell, comprising:

[0039] The cover plate 100 has a first surface 130 and a second surface 140 opposite to each other along a first direction, and the cover plate 100 is provided with an explosion-proof hole 110 penetrating the first surface 130 and the second surface 140;

[0040] An explosion-proof disk 200 covers the explosion-proof hole 110; and

[0041] The on-off valve 300 is installed on the second surface 140 , and the on-off valve 300 and the explosion-proof disk 200 are combined to form a closed pressure relief space 400 ;

[0042] When the gas in the battery cell applies pressure to the opening and closing valve 300 and reaches a certain threshold, the opening and closing valve 300 forms a pressure relief channel, so that the gas enters the pressure relief space 400 .

[0043] Specifically, the first direction is the thickness direction of the cover plate, and the opening and closing valve 300 is opened to form an opening under the action of air pressure, so that the gas between the battery cell and the battery cover plate can enter the pressure relief space 400 through the opening of the opening and closing valve 300, so that the air pressure between the battery cell and the cover plate (here equivalent to the air pressure on the side of the opening and closing valve 300 away from the explosion-proof plate 200) and the air pressure in the pressure relief space 400 are consistent, so that the gas generated by the internal reaction of the battery cell can reach the explosion-proof plate 200 through the opening and closing valve 300. When the pressure in the pressure relief space 400 reaches the set value, the gas generated in the battery can be discharged normally through the explosion-proof plate 200 to ensure that the battery can be depressurized smoothly and ensure the safety of the battery during use.

[0044] When the air pressure in the pressure relief space 400 is greater than or equal to the air pressure on the side of the opening and closing valve 300 away from the explosion-proof disk 200, the opening and closing valve 300 remains in a closed state. The opening and closing valve 300 can not only isolate the electrolyte from entering, but also replace the explosion-proof disk 200 to corrode first, thereby extending the time that the battery cover is not corroded and leaking, and improving the service life of the battery.

[0045] Optionally, the explosion-proof hole 110 is disposed at the center of the cover plate 100 .

[0046] The projection of the opening and closing valve 300 in the first direction completely covers the explosion-proof hole 110. It can be understood that the opening and closing valve 300 also completely covers the explosion-proof disk 200. There is a gap between the opening and closing valve 300 and the explosion-proof disk 200, so that the two opposing surfaces of the opening and closing valve 300 and the explosion-proof disk 200 enclose a pressure relief space 400.

[0047] It should be noted that when the air pressure in the pressure relief space 400 is lower than the air pressure on the side of the opening and closing valve 300 away from the explosion-proof disk 200, the opening and closing valve 300 opens under the action of the air pressure to form an opening, so that external gas can enter the pressure relief space 400 through the opening and closing valve 300.

[0048] like Figures 3 to 5 As shown, in some embodiments, the inner wall of the explosion-proof hole 110 protrudes into the explosion-proof hole 110 to form a step portion 120, which extends circumferentially along the explosion-proof hole 110 to be closed, and the edge area of ​​the explosion-proof plate 200 is fixed on the step portion 120.

[0049] Optionally, the explosion-proof disc 200 is fixedly connected to the surface of the step portion 120 facing away from the closing valve.

[0050] It should be noted that the edge of the explosion-proof disk 200 is sealed and connected to the step portion 120 to form a sealed connection structure inside the explosion-proof hole 110 to prevent gas or liquid from passing through the explosion-proof hole 110 .

[0051] like Figure 4 and Figure 5 As shown, in some embodiments, the opening and closing valve 300 includes a protective cover 310 and a valve plate 320, the outer edge of the protective cover 310 is fixed on the cover plate 100, and the valve plate 320 is assembled on the protective cover 310; when the gas applies pressure to the valve plate 320 and reaches a certain threshold, the valve plate 320 moves in a direction toward the second surface 140, and a pressure relief channel is formed between the protective cover 310 and the valve plate 320.

[0052] The edge of the protective cover 310 is fixedly connected to the cover plate 100 to improve the stability of the protective cover 310 on the cover plate 100. In addition, the valve plate 320 is arranged on the side of the protective cover 310 facing the explosion-proof disk 200, and along the first direction, the valve plate 320 is movably connected to the protective cover 310, and the valve plate 320 completely covers the mounting hole 311. The connection between the valve plate 320 and the protective cover 310 includes any one of a sliding connection, a hinged connection or an elastic connection.

[0053] like Fig. 9 As shown, in some embodiments, the maximum distance that the valve plate 320 moves in the direction toward the second surface 140 is S1, and the minimum distance between the end of the valve plate 320 close to the cover plate and the second surface 140 is S2, wherein S2>S1>0.

[0054] It should be noted that the position limiting member 500 is configured such that: when the air pressure in the pressure relief space 400 is less than the air pressure on the side of the opening and closing valve 300 away from the explosion-proof disk 200, the valve plate 320 moves a preset distance in a direction away from the protective cover 310 under the action of the air pressure outside the pressure relief space 400, so as to form an opening between the valve plate 320 and the protective cover 310. At the same time, one end of the position limiting member 500 away from the valve plate 320 abuts against the protective cover 310, so as to limit the moving distance of the valve plate 320 through the position limiting member 500, and prevent the valve plate 320 from abutting against the explosion-proof disk 200 during the movement, thereby ensuring the integrity of the explosion-proof disk 200.

[0055] It is understandable that when the valve plate 320 moves toward the explosion-proof disc 200, since the end of the valve plate 320 close to the explosion-proof disc 200 is the shortest to the explosion-proof disc 200, it can first contact the explosion-proof disc 200. Based on this, the moving distance S1<S2 of the valve plate 320 is controlled by the limiter 500 to prevent the valve plate 320 from touching or squeezing the explosion-proof disc 200 during the movement. 0<S1, that is, the valve plate 320 can form a gap with the protective cover 310 under the action of the air pressure outside the pressure relief space 400, so that the gas outside the pressure relief space 400 can enter the pressure relief space 400 through the gap, thereby ensuring the smoothness of the connection between the pressure relief space 400 and the external space.

[0056] like Figures 7 to 9 As shown, in some embodiments, the protective cover 310 includes a connecting ring 313 and a first guide ring 312. The connecting ring 313 is located in the outer peripheral area of ​​the explosion-proof hole 110. One end of the first guide ring 312 is connected to the connecting ring 313, and the other end extends obliquely in a direction away from the second surface 140 to form a mounting hole 311. The valve plate 320 closes the mounting hole 311, and a pressure relief channel is formed between the first guide ring 312 and the valve plate 320.

[0057] The connecting ring 313 is disposed around the edge of the first guide ring 312 and is integrally formed with the first guide ring 312 to form the protective cover 310. In addition, the connecting ring 313 is fixedly connected to the cover plate 100 to form a sealed connection structure between the protective cover 310 and the cover plate 100.

[0058] like Figure 3 and Figure 7 As shown, in some embodiments, the valve plate 320 includes a second guide ring 322 and a sealing portion 321. The second guide ring 322 is inclined in a direction away from the second surface 140 and is in contact with the first guide ring 312. The edge of the second guide ring 322 is connected to the sealing portion 321 to close the pressure relief space 400.

[0059] When the second guide ring 322 is attached to the first guide ring 312, the on-off valve 300 is in a closed state. In addition, when the second guide ring 322 is separated from the first guide ring 312, the on-off valve 300 is in an open state. Optionally, the second guide ring 322 is surrounded by the edge of the blocking portion 321, and the second guide ring 322 and the blocking portion 321 are integrally formed to form the valve plate 320.

[0060] like Figure 7 and Fig. 9 As shown, in some embodiments, the side of the first guide ring 312 facing the explosion-proof disk 200 is a concave surface 312a, and the side of the second guide ring 322 facing the protective cover 310 is provided with a convex surface 322a, and the convex surface 322a is partially in contact with the concave surface 312a.

[0061] It should be noted that the side of the first guide ring 312 facing the explosion-proof disc 200 is a concave surface 312a, that is, there is a gap between the first guide ring 312 and the cover plate 100, so that the two surfaces of the opening and closing valve 300 and the explosion-proof disc 200 opposite to each other can be enclosed to form a pressure relief space 400. Along the first direction, the coverage area of ​​the concave surface 312a gradually decreases from the side close to the explosion-proof disc 200 to the side away from the explosion-proof disc 200, so that the side of the first guide ring 312 facing the concave surface 312a of the valve disc 320 can fit with the concave surface 312a, and the concave surface 312a provides support and limit to the valve disc 320, so as to prevent the valve disc 320 from falling out of the mounting hole, so as to improve the stability of the valve disc 320 in the pressure relief space 400. In addition, a convex surface 322a is provided on the side of the second guide ring 322 facing the protective cover 310. Along the first direction, the coverage area of ​​the convex surface 322a gradually decreases from the side close to the explosion-proof plate 200 to the side away from the explosion-proof plate 200, so that the convex surface 322a is partially fitted with the concave surface 312a to seal the mounting hole 311 set on the protective cover 310, thereby forming a closed opening and closing valve 300.

[0062] It should be noted that when the air pressure in the pressure relief space 400 is greater than or equal to the air pressure on the side of the opening and closing valve 300 away from the explosion-proof disk 200, the concave surface 312a and the convex surface 322a partially fit together to seal the installation hole 311, that is, the opening and closing valve 300 is closed.

[0063] When the air pressure in the pressure relief space 400 is lower than the air pressure on the side of the opening and closing valve 300 away from the explosion-proof disc 200, the valve disc 320 moves toward the cover plate 100 under the action of the gas pressure in the pressure relief space 400. At this time, the concave surface 312a is separated from the convex surface 322a, that is, the opening and closing valve 300 is opened.

[0064] Specifically, when the valve plate 320 is separated from the protective cover 310 by the external air pressure to form an opening, when the air pressure in the pressure relief space 400 is equal to the air pressure outside the pressure relief space 400, the valve plate 320 can move toward the protective cover 310 under the action of its own gravity. During the movement of the valve plate 320, the limiting member 500 provides guidance and limiting effects on the valve plate 320, so that the valve plate 320 slides along the first direction, and the valve plate 320 is prevented from tilting or deflecting during the movement toward the protective cover 310, and the concave surface 312a and the convex surface 322a are partially fitted, so that the valve plate 320 can completely cover the installation hole 311 and seal the installation hole 311 to form a closed opening and closing valve 300.

[0065] like Figure 6 , Figure 7 and Fig. 9As shown, in some embodiments, the valve plate 320 includes at least one limit member 500 on a side facing away from the explosion-proof plate 200, and the limit member 500 has a slot 530, which is snapped into the edge area of ​​the protective cover 310 away from the cover plate 100 to fix the valve plate 320 on the protective cover 310.

[0066] The number of the limiting members 500 can be one, two or more than two, and can be set according to the actual situation. Optionally, when there are two limiting members 500, the two limiting members 500 are respectively arranged on two opposite sides of the valve plate 320, so that the two limiting members 500 and the protective cover 310 are limited, and the two limiting members 500 and the inner wall of the mounting hole 311 are used to guide and limit the valve plate 320, so as to avoid the valve plate 320 from tilting or not completely fitting with the protective cover 310 when contacting, and ensure the stability and smoothness of the valve plate 320 during the movement, thereby improving the smoothness of opening or closing the opening and closing valve 300.

[0067] In addition, there is a gap between the limit member 500 and the inner wall of the mounting hole 311 or the limit member 500 is slidably connected to the inner wall of the mounting hole 311 to reduce the friction generated between the limit member 500 and the inner wall of the mounting hole 311 during the movement of the limit member 500 relative to the protective cover 310, thereby ensuring the smoothness of the limit member 500 and the valve plate 320 during the movement.

[0068] In other embodiments, a limit member 500 is provided on the edge of the valve plate 320 on the side facing the protective cover 310. The limit member 500 is a hinge, and the hinge is arranged between the valve plate 320 and the protective cover 310 so as to hinge the valve plate 320 and the protective cover 310 through the hinge, that is, the valve plate 320 can rotate relative to the protective cover 310.

[0069] When the air pressure in the pressure relief space 400 is equal to the air pressure on the side of the opening and closing valve 300 away from the explosion-proof disk 200, at this time, the end of the valve plate 320 away from the hinge moves toward the protective cover 310 under the action of gravity to seal the mounting hole 311. It can be understood that the hinge can limit the valve plate 320, and can also effectively control the swing direction of the valve plate 320, thereby improving the stability of the opening or closing of the opening and closing valve 300.

[0070] like Figure 7 and Fig. 9 As shown, in some embodiments, the limiting member 500 includes an extension portion 510 and a limiting portion 520; one end of the extension portion 510 is fixedly connected to the blocking portion 321, and the other end passes through the mounting hole 311 and is connected to the limiting portion 520 to form a slot 530.

[0071] It should be noted that, in this embodiment, the outer surface of the extension portion 510 is in contact with the inner wall of the mounting hole 311, and the extension portion 510 is slidably connected to the inner wall of the mounting hole 311, so as to provide guidance and limiting functions for the valve plate 320 during the movement along the first direction through the extension portion 510 and the inner wall of the mounting hole 311, thereby preventing the valve plate 320 from swinging or shaking during the movement along the first direction, and improving the stability and smoothness of the valve plate 320 during the movement.

[0072] Specifically, the extending portion 510 and the limiting portion 520 are perpendicular to each other, that is, the extending portion 510 and the limiting portion 520 are connected to form an “L”-shaped limiting member 500 .

[0073] In the projection along the first direction, the limiting portion 520 and the protective cover 310 at least partially overlap, so that the limiting portion 520 can form a limit with the protective cover 310 during the process of moving along the first direction.

[0074] It is understandable that when the valve plate 320 moves along the first direction, the overlapping portion of the limiting portion 520 and the protective cover 310 can abut against the protective cover 310, thereby controlling the movement distance of the valve plate 320 to prevent the valve plate 320 from contacting or squeezing the explosion-proof plate 200 during movement.

[0075] Some embodiments of the present application provide a battery, including a shell, an electrode assembly and the pressure relief assembly of the battery cell described above, wherein the shell has at least one opening along a first direction, and a cover plate closes the opening.

[0076] Optionally, an opening is formed on one side of the shell, the edge of the cover is sealed to the inner wall of the opening to seal the opening, the electrode assembly is accommodated inside the shell, and the opening and closing valve 300 is arranged on the side of the explosion-proof disc 200 facing the battery cell.

[0077] The battery provided in this embodiment has the technical effects produced by the pressure relief assembly of the battery cell in any of the above embodiments, which will not be described in detail here.

[0078] It should be noted that if the negative electrode column overlaps the shell, a gas pressure opening and closing valve is provided on the side of the explosion-proof plate 200 facing the battery cell. The opening and closing valve 300 can not only isolate the electrolyte and thus block the ion path, but the protective cover 310 can also be used as the anode in the sacrificial anode protection method. The protective cover 310 can replace the explosion-proof plate 200 and corrode preferentially, thereby extending the time that the explosion-proof plate 200 is not corroded by leakage and improving the service life of the battery.

[0079] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limiting, and thus other examples of the exemplary embodiments may have different values.

[0080] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0081] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A pressure relief assembly for a battery cell, characterized in that: include: A cover plate having a first surface and a second surface opposite to each other along a first direction, wherein the cover plate is provided with an explosion-proof hole penetrating the first surface and the second surface; An explosion-proof plate, covering the explosion-proof hole; as well as An opening and closing valve is installed on the second surface, and the opening and closing valve and the explosion-proof disk are combined to form a closed pressure relief space; When the gas in the battery cell applies pressure to the opening and closing valve and reaches a certain threshold, the opening and closing valve forms a pressure relief channel, so that the gas enters the pressure relief space.

2. The pressure relief assembly of the battery cell according to claim 1, characterized in that: The inner wall of the explosion-proof hole protrudes into the inside of the explosion-proof hole to form a step portion, the step portion extends along the circumference of the explosion-proof hole to be closed, and the edge area of ​​the explosion-proof plate is fixed on the step portion.

3. The pressure relief assembly of the battery cell according to claim 1, characterized in that: The on-off valve comprises a protective cover and a valve plate, the outer edge of the protective cover is fixed on the cover plate, and the valve plate is assembled on the protective cover; When the gas applies pressure to the valve sheet and reaches a certain threshold, the valve sheet moves in a direction toward the second surface, forming the pressure relief channel between the protective cover and the valve sheet.

4. The pressure relief assembly of the battery cell according to claim 3, characterized in that: The maximum distance that the valve plate moves in the direction toward the second surface is S1, and the minimum distance between the end of the valve plate close to the cover plate and the second surface is S2, wherein S2>S1>0.

5. The pressure relief assembly of the battery cell according to claim 3, characterized in that: The protective cover includes a connecting ring and a first guide ring, the connecting ring is located in the outer peripheral area of ​​the explosion-proof hole, one end of the first guide ring is connected to the connecting ring, and the other end extends obliquely in a direction away from the second surface to form a mounting hole, the valve plate closes the mounting hole, and the pressure relief channel is formed between the first guide ring and the valve plate.

6. The pressure relief assembly of the battery cell according to claim 5, characterized in that: The valve plate includes a second guide ring and a sealing portion. The second guide ring is inclined in a direction away from the second surface and is in contact with the first guide ring. The sealing portion is connected to an edge of the second guide ring to close the pressure relief space.

7. The pressure relief assembly of the battery cell according to claim 6, characterized in that: The side of the first guide ring facing the explosion-proof disk is a concave surface, and the side of the second guide ring facing the protective cover is provided with a convex surface, and the convex surface is partially in contact with the concave surface.

8. The pressure relief assembly of the battery cell according to claim 6, characterized in that: The valve plate includes at least one stopper on a side facing away from the explosion-proof plate, wherein the stopper has a slot, and the slot is engaged with an edge area of ​​the protective cover away from the cover plate to fix the valve plate on the protective cover.

9. The pressure relief assembly of the battery cell according to claim 8, characterized in that: The limiting member includes an extending portion and a limiting portion; one end of the extending portion is fixedly connected to the blocking portion, and the other end passes through the mounting hole and is connected to the limiting portion to form the slot.

10. A battery, characterized in that: A pressure relief assembly comprising a housing, an electrode assembly and a battery cell according to any one of claims 1 to 9, wherein the housing has at least one opening along the first direction, and the cover plate closes the opening.

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