CN216903232U

CN216903232U - Pressure relief device, single battery, battery and electric equipment

Info

Publication number: CN216903232U
Application number: CN202220220729.XU
Authority: CN
Inventors: 方堃; 郭志君; 金海族
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-01-26
Filing date: 2022-01-26
Publication date: 2022-07-05
Anticipated expiration: 2032-01-26

Abstract

The embodiment of the application provides a pressure relief device, a single battery, a battery and electric equipment, and belongs to the technical field of batteries. The embodiment of the application provides a pressure relief device for single battery, pressure relief device includes pressure release body and two pressure release grooves. The pressure relief body has a first surface and a second surface which are oppositely arranged along the thickness direction of the pressure relief body. The two pressure relief grooves are oppositely arranged along the thickness direction and are respectively arranged on the first surface and the second surface, a weak portion is formed between the two pressure relief grooves, and the weak portion is configured to be cracked when the pressure or the temperature inside the battery monomer reaches a threshold value so as to relieve the pressure inside the battery monomer. The first surface and the second surface of pressure release body all are equipped with the pressure release groove, can obtain lower remaining thickness, have reduced the thickness of weak part for the weak part splits more easily, reduces pressure relief device's detonation pressure, makes the pressure release body can in time release the pressure, reduces the free risk of a fire, explosion etc. of battery and appears, effectively improves the free security of battery.

Description

Pressure relief device, single battery, battery and electric equipment

Technical Field

The application relates to the technical field of batteries, in particular to a pressure relief device, a single battery, a battery and electric equipment.

Background

With the development of new energy technology, batteries are more and more widely used, for example, in mobile phones, notebook computers, battery cars, electric automobiles, electric airplanes, electric ships, electric toy cars, electric ships, electric toy airplanes, electric tools, and the like.

In addition to improving the performance of the battery cell, safety issues are also a concern in the development of battery technology. Therefore, how to improve the safety of the battery cell is a problem to be solved urgently in the battery technology.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a pressure relief device, a single battery, a battery and electric equipment, and can effectively improve the safety of the single battery.

In a first aspect, an embodiment of the present application provides a pressure relief device, for a battery cell, including: the pressure relief body is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; two pressure relief grooves, set up along the thickness direction is relative, and set up respectively in the first surface and the second surface, form weak part between two the pressure relief grooves, the weak part is configured to split when the pressure or the temperature in the battery monomer reach the threshold value, in order to bleed the pressure in the battery monomer.

Among the above-mentioned technical scheme, the first surface and the second surface of pressure release body all are equipped with the pressure release groove, can obtain lower residual thickness, have reduced the thickness of weak part for the weak part splits more easily, reduces pressure relief device's detonation pressure, makes the pressure release body can in time release the pressure, reduces the free risk such as the battery appears catching fire, explosion, effectively improves the free security of battery.

In some embodiments, the distance between the first surface and the second surface is a first distance, and a ratio of the minimum thickness of the weakened portion to the first distance is 0.12-0.5. The ratio of the minimum thickness of the weak part to the first distance is too small, so that the minimum thickness of the weak part is small, the weak part can be cracked in the forming process, even if the weak part is not cracked, the strength of the pressure relief body is poor, the weak part is cracked and relieved in a vibration environment or when the pressure or the temperature inside the battery monomer does not reach a threshold value, and the service life of the battery monomer is influenced. The ratio of the minimum thickness of the weak part to the first distance is too large, so that the minimum thickness of the weak part is large, the pressure or the temperature of the weak part in the single battery body reaches a threshold value easily, the weak part does not crack and release pressure, the pressure release is not timely, and accidents such as fire and explosion of the single battery body are caused. Therefore, the ratio of the minimum thickness of the weak part to the first distance is set to be 0.12-0.5, so that the pressure relief device can be guaranteed to timely relieve pressure when the internal pressure of the single battery reaches a threshold value, and the pressure relief device can be guaranteed to have enough strength before pressure relief.

In some embodiments, the pressure relief groove extends along a circumferential direction of the pressure relief body and defines a pressure relief portion; the pressure relief portion is configured to open with the weak portion as a boundary when a pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell. The structure effectively improves the pressure relief area of the pressure relief device, further improves the pressure relief speed of the pressure relief device, reduces the risks of fire, explosion and the like of the single battery, and improves the safety of the single battery.

In some embodiments, the pressure relief body is circumferentially spaced from the pressure relief groove. Like this, the weak part is when splitting the pressure release, and the region between the pressure release groove both ends can not split for the pressure release portion can be opened with the mode of outside upset, prevents that the pressure release portion wholly drops the departure when the pressure release.

In some embodiments, the pressure relief groove is in the shape of a circular arc extending along the circumferential direction of the pressure relief body. The pressure relief groove of the structure is regular in shape and easy to machine and form, so that the pressure relief portion can be regularly opened during pressure relief.

In some embodiments, the pressure relief body further has an outer surface and an inner surface, the outer surface is disposed opposite to the inner surface along the thickness direction, and the pressure relief portion is configured to open in a direction from the inner surface to the outer surface when a pressure or temperature inside the battery cell reaches a threshold value; the pressure relief body is provided with a concave portion, the concave portion is recessed from the outer surface along the direction close to the inner surface along the thickness direction, and the bottom surface of the concave portion forms the first surface. The concave part can provide when outwards opening for the pressure relief portion and dodge the space, even there is the obstacle in the surface of pressure relief body, also can guarantee that the pressure relief portion normally opens, reduces because of the obstacle with the surface counterbalance causes the unable risk of opening of pressure relief portion.

In some embodiments, a convex portion protruding from the inner surface is formed at a position of the pressure relief body corresponding to the concave portion, and a surface of the convex portion facing away from the inner surface forms the second surface along the thickness direction. The setting of convex part can improve the intensity that the pressure release body set up the region of concave part, avoids appearing setting up the problem that the concave part leads to local strength not enough because of the pressure release body.

In some embodiments, the pressure relief groove comprises: two groove side surfaces which are arranged along the width direction of the pressure relief groove and face each other; a groove bottom surface connected to the two groove side surfaces; wherein an area between groove bottoms of the two relief grooves forms the weak portion. The pressure relief groove with the structure is easy to machine and form, and can be formed in a stamping forming mode.

In some embodiments, the groove bottom surface is a circular arc surface recessed in a depth direction of the pressure relief groove. This kind of structure makes the weak part be the structure that reduces gradually from both sides to intermediate position thickness for the weak part can split from the position that the centre is weakest when the pressure release, makes the weak part split more easily, guarantees that the weak part can in time split the pressure release when pressure or the temperature of pressure relief device in the battery monomer inside reach the threshold value.

In some embodiments, the groove bottom surface comprises a bottom plane and an arc-shaped chamfer surface, and the bottom plane is connected with each groove side surface through one arc-shaped chamfer surface. The structure enables the middle area (the area corresponding to the bottom plane) of the weak part to be weakest, so that the weak part is easier to crack, and the weak part can be cracked and decompressed in time when the pressure or the temperature inside the battery cell reaches a threshold value.

In some embodiments, the distance between two of the groove sides gradually decreases in the depth direction of the pressure relief groove. This structure can effectively reduce the width of the weak portion, so that the weak portion is more likely to be ruptured when the pressure or temperature inside the battery cell reaches a threshold value.

In some embodiments, an oxidation resistant layer is formed on a surface layer of the pressure relief body, and the oxidation resistant layer is arranged in an area where the pressure relief groove is arranged and extends along a groove wall surface of the pressure relief groove. The antioxidation layer plays a role in protecting the pressure relief body and prevents the pressure relief body from being oxidized. Certainly, because the antioxidation layer extends along the groove wall surface of pressure relief groove in the region that sets up the pressure relief groove and arranges, the antioxidation layer also can play the guard action to the region that pressure relief body set up the pressure relief groove, reduces the pressure relief body and in the region that sets up the pressure relief groove by the oxidation, and lead to the risk that weak part intensity weakens.

In some embodiments, the thickness of the oxidation resistant layer in the region of the pressure relief grooves is less than the thickness of the oxidation resistant layer in the remaining regions. The influence of the oxidation resistant layer in the pressure relief groove area on the weak part is reduced, and the weak part can be cracked to relieve pressure in time when the pressure or the temperature inside the battery monomer reaches a threshold value.

In a second aspect, an embodiment of the present application provides a battery cell, including; an electrode assembly: a casing for housing the electrode assembly, the casing comprising a pressure relief device as provided in any one of the embodiments of the first aspect above.

In some embodiments, the case further comprises a case for accommodating the electrode assembly, the case has an opening, and the pressure relief body is used for covering the opening.

In a third aspect, an embodiment of the present application provides a battery, including: the battery cell provided in any one of the embodiments of the second aspect; and the box body is used for accommodating the battery monomer.

In a fourth aspect, an embodiment of the present application provides an electric device, including the battery provided in any one of the embodiments of the third aspect.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

fig. 2 is an exploded view of a battery provided in accordance with some embodiments of the present application;

fig. 3 is an exploded view of a battery cell provided in some embodiments of the present application;

FIG. 4 is a schematic diagram of the pressure relief device shown in FIG. 3;

FIG. 5 is a partial view of the pressure relief device shown in FIG. 4;

FIG. 6 is a cross-sectional view A-A of the pressure relief device shown in FIG. 4;

FIG. 7 is an enlarged partial view of a pressure relief device provided in accordance with certain embodiments of the present application;

FIG. 8 is an enlarged partial view of a pressure relief device provided in accordance with other embodiments of the present application;

FIG. 9 is a partial cross-sectional view of a pressure relief device provided in accordance with other embodiments of the present application;

FIG. 10 is a flow chart of a method of manufacturing a pressure relief device provided in some embodiments of the present application;

fig. 11 is a schematic block diagram of an apparatus for manufacturing a pressure relief device provided in some embodiments of the present application.

Icon: 10-a box body; 11-a first part; 12-a second part; 20-a battery cell; 21-an electrode assembly; 22-a housing; 23-end caps; 24-a pressure relief device; 241-a pressure relief body; 2411-a first surface; 2412-a second surface; 2413-a weakening; 2414-pressure relief; 2415-an outer surface; 2415 a-a recess; 2415 b-a solder bath; 2416-inner surface; 2416 a-a convex part; 2416 b-bumps; 2417-antioxidation layer; 242-pressure relief groove; 2421-slot side; 2422-bottom of groove; 2422 a-bottom plane; 2422b — arc chamfer surface; 25-an electrode terminal; 26-a current collecting member; 100-a battery; 200-a controller; 300-a motor; 1000-a vehicle; 2000-manufacturing equipment; 2100-providing means; 2200-a processing device; x-width direction; y-circumferential direction; z-thickness direction.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the above-described drawings are used for distinguishing between different elements and not for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "attached" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The term "and/or" in this application is only one kind of association relationship describing the associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this application generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cells are generally divided into three types in an encapsulation manner: the cylindrical battery monomer, the square battery monomer and the soft package battery monomer are also not limited in the embodiment of the application.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charge or discharge of battery cells.

The battery monomer comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive pole piece, a negative pole piece and an isolating membrane. The battery cell mainly depends on metal ions to move between the positive pole piece and the negative pole piece to work. The positive pole piece includes anodal mass flow body and anodal active substance layer, and anodal active substance layer coats in anodal mass flow body's surface, and the anodal mass flow body protrusion in the anodal mass flow body that has coated anodal active substance layer of uncoated anodal active substance layer, and the anodal mass flow body that does not coat anodal active substance layer is as anodal utmost point ear. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative pole mass flow body and negative pole active substance layer, and the negative pole active substance layer coats in the surface of negative pole mass flow body, and the negative pole mass flow body protrusion in the negative pole mass flow body of coating the negative pole active substance layer not coating the negative pole active substance layer, and the negative pole mass flow body of not coating the negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not fused when a large current is passed, the number of the positive electrode tabs is multiple and the positive electrode tabs are stacked together, and the number of the negative electrode tabs is multiple and the negative electrode tabs are stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may have a winding structure or a lamination structure, and the embodiment of the present application is not limited thereto.

The development of battery technology needs to consider various design factors, such as energy density, cycle life, discharge capacity, charge and discharge rate, and other performance parameters, and also needs to consider the safety of the battery.

In the battery monomer, for guaranteeing the free security of battery, generally can set up pressure relief device in the battery monomer, when battery monomer internal pressure or temperature reached the threshold value, release the free internal pressure of battery through pressure relief device to guarantee the free security of battery.

The inventor has noticed that even if the pressure relief device is provided in the battery cell, safety problems such as fire, explosion, etc. of the battery cell still occur. The inventor further researches and discovers that in the related art, a pressure relief device is generally provided with a pressure relief groove on a pressure relief body, and the pressure relief body is cracked from the position where the pressure relief groove is arranged during pressure relief so as to achieve the purpose of pressure relief. The inventor's deep research discovery, generally, the single face sets up the pressure release groove on the pressure release body, will reach the design requirement, guarantee that the pressure release body in time releases the pressure when battery monomer internal pressure or temperature reach the threshold value, need to process the pressure release groove to certain degree of depth, make the pressure release body can not be too thick at the residual thickness that sets up behind the pressure release groove, nevertheless receive the restriction of processing technology and pressure release body material, under the condition that the material of pressure release body is thicker and/or pressure release body is harder, it hardly makes residual thickness reach the design requirement to process the pressure release groove at pressure release body single face, make pressure relief device's detonation pressure great, lead to unable pressure release when pressure relief device should release the pressure, can't in time release battery monomer inside pressure, thereby the safety problems such as battery monomer fires appear, explode.

In view of this, the present disclosure provides a pressure relief device, in which a pressure relief groove is disposed on each of a first surface and a second surface opposite to a pressure relief body, and a weak portion is formed between the pressure relief groove on the first surface and the pressure relief groove on the second surface, and the weak portion is configured to be ruptured when a pressure or a temperature inside a battery cell reaches a threshold value, so as to relieve the pressure inside the battery cell.

In such pressure relief device, the first surface and the second surface of pressure relief body all are equipped with the pressure relief groove, can obtain lower remaining thickness, have reduced the thickness of weak part for the weak part splits more easily, reduces pressure relief device's detonation pressure, makes the pressure relief body can in time release the pressure, reduces the free risk such as the battery appears on fire, explosion, effectively improves the free security of battery.

In addition, because the first surface and the second surface of pressure release body all are equipped with the pressure release groove, can effectively reduce the shaping degree of difficulty, guarantee the machining precision, the thickness of accurate control weak part for the thickness of weak part reaches detonating requirement.

The pressure relief device described in the embodiments of the present application is suitable for a battery cell, a battery, and an electric device using the battery.

The electric equipment can be vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like; spacecraft include aircraft, rockets, space shuttles, and spacecraft, among others; electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and electric power tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not specifically limit the above-mentioned electric devices.

For convenience of explanation, the following embodiments will be described by taking an electric device as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present disclosure, a battery 100 is disposed inside the vehicle 1000, and the battery 100 may be disposed at a bottom portion, a head portion, or a tail portion of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may serve as an operation power source of the vehicle 1000.

The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to supply power to the motor 300, for example, for starting, navigation, and operational power requirements while the vehicle 1000 is traveling.

In some embodiments of the present application, the battery 100 may be used not only as an operating power source of the vehicle 1000, but also as a driving power source of the vehicle 1000, instead of or in part of fuel or natural gas, to provide driving power for the vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to some embodiments of the present disclosure, in which the battery 100 includes a case 10 and a battery cell 20, and the case 10 is used for accommodating the battery cell 20.

The case 10 is a component for accommodating the battery cell 20, the case 10 provides an accommodating space for the battery cell 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, and the first portion 11 and the second portion 12 cover each other to define a receiving space for receiving the battery cell 20. The first and

second portions

11 and 12 may be in various shapes, such as rectangular parallelepiped, cylindrical, etc. The first portion 11 may be a hollow structure with one side open, the second portion 12 may also be a hollow structure with one side open, and the open side of the second portion 12 is covered on the open side of the first portion 11, thereby forming the box body 10 with a receiving space. The first portion 11 may have a hollow structure with one side opened, the second portion 12 may have a plate-like structure, and the second portion 12 may cover the opened side of the first portion 11 to form the case 10 having the receiving space. The first part 11 and the second part 12 may be sealed by a sealing element, which may be a sealing ring, a sealant or the like.

In the battery 100, one or more battery cells 20 may be provided. If there are a plurality of battery cells 20, the plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel, where in series-parallel refers to that the plurality of battery cells 20 are connected in series or in parallel. A plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel to form a battery module, and a plurality of battery modules may be connected in series, in parallel, or in series-parallel to form a whole, and may be accommodated in the box 10. Or all the battery cells 20 may be directly connected in series or in parallel or in series-parallel, and the whole of all the battery cells 20 is accommodated in the case 10.

In some embodiments, the battery 100 may further include a bus member, and the plurality of battery cells 20 may be electrically connected to each other through the bus member, so as to connect the plurality of battery cells 20 in series or in parallel or in series-parallel. The bus member may be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, or the like.

Referring to fig. 3, fig. 3 is an exploded view of a battery cell 20 according to some embodiments of the present disclosure, and the battery cell 20 may include a case and an electrode assembly 21, where the case is used to accommodate the electrode assembly 21. The housing may include a housing 22, an end cap 23, and a pressure relief device 24.

The case 22 is a member for accommodating the electrode assembly 21, the case 22 may be a hollow structure having one end opened, and the case 22 may be a hollow structure having opposite ends opened. The housing 22 may be of various shapes, such as a cylinder, a rectangular parallelepiped, or the like. The material of the housing 22 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

The electrode assembly 21 is a part in which electrochemical reactions occur in the battery cell 20. The electrode assembly 21 may include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 21 may have a winding structure formed by winding a positive electrode tab, a separator, and a negative electrode tab, or a lamination structure formed by stacking a positive electrode tab, a separator, and a negative electrode tab. The electrode assembly 21 has a cathode tab, which may be a portion of the cathode sheet not coated with the cathode active material layer, and an anode tab, which may be a portion of the anode sheet not coated with the anode active material layer.

The end cap 23 is a member that covers an opening of the case 22 to isolate the internal environment of the battery cell 20 from the external environment. The cap 23 covers an opening of the case 22, and the cap 23 and the case 22 together define a sealed space for accommodating the electrode assembly 21, the electrolyte, and other components. The shape of the end cap 23 can be adapted to the shape of the housing 22, for example, the housing 22 is a rectangular parallelepiped structure, the end cap 23 is a rectangular plate structure adapted to the housing 22, and for example, the housing 22 is a cylinder structure, and the end cap 23 is a circular plate structure adapted to the housing 22. The end cap 23 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

In the battery cell 20, one or two end caps 23 may be provided. If the housing 22 is a hollow structure with an opening formed at one end, one end cover 23 is correspondingly arranged. If the housing 22 is a hollow structure with openings formed at two ends, two end covers 23 are correspondingly disposed, and the two end covers 23 respectively cover the two openings of the housing 22.

An electrode terminal 25 may be disposed in the battery cell, the electrode terminal 25 may be disposed on the end cap 23 or the case 22, and the electrode terminal 25 is electrically connected to the electrode assembly 21 to output electric energy of the battery cell 20. In the embodiment where there are two end caps 23 in the battery cell 20, both end caps 23 may be provided with electrode terminals 25, and the electrode terminal 25 on one end cap 23 may be electrically connected to a positive electrode tab of the electrode assembly 21, and the electrode terminal 25 on the other end cap 23 may be electrically connected to a negative electrode tab of the electrode assembly 21. As shown in fig. 3, in the embodiment in which the end cap 23 is one in the battery cell 20, only the case may be provided with the electrode terminal 25, and the electrode terminal 25 may be electrically connected to a positive electrode tab of the electrode assembly 21, and the end cap 23 may be electrically connected to a negative electrode tab of the electrode assembly 21.

A current collecting member 26 may also be provided in the battery cell 20 to electrically connect the electrode terminal 25 with a tab or the end cap 23 with a tab. Taking the end cap 23 of the battery cell 20 as an example, the electrode terminal 25 on the case 22 and the positive electrode tab of the electrode assembly 21 are connected by one current collecting member 26, and the end cap 23 and the negative electrode tab of the electrode assembly 21 are connected by the other current collecting member 26.

The pressure relief device 24 is a component that relieves the pressure inside the battery cell 20, and when the pressure or temperature inside the battery cell 20 reaches a threshold value, the pressure inside the battery cell 20 is relieved through the pressure relief device 24. The specific structure of the pressure relief device 24 is explained in detail below with reference to the drawings.

Referring to fig. 4 and 5, fig. 4 is a schematic structural view of the pressure relief device 24 shown in fig. 3, and fig. 5 is a partial view of the pressure relief device 24 shown in fig. 4, in an embodiment of the present disclosure, a pressure relief device 24 is provided for a battery cell 20, and the pressure relief device 24 includes a pressure relief body 241 and two pressure relief grooves 242. Pressure relief body 241 has a first surface 2411 and a second surface 2412 disposed opposite to each other in the thickness direction Z. The two pressure relief grooves 242 are disposed opposite to each other along the thickness direction Z of the pressure relief device 24 and are respectively disposed on the first surface 2411 and the second surface 2412. A weak portion 2413 is formed between the two pressure relief grooves 242, and the weak portion 2413 is configured to rupture when the pressure or temperature inside the battery cell 20 reaches a threshold value, to relieve the pressure inside the battery cell 20.

Pressure relief body 241 may be either end cap 23 itself or housing 22 itself. The pressure relief body 241 may be a separate component mounted on the end cap 23, or may be a separate component mounted on the housing 22, such as an explosion-proof valve, an explosion-proof plate, or the like. The shape of the pressure relief body 241 may be various, and for example, the pressure relief body 241 is used as the end cap 23, and the pressure relief body 241 may be rectangular, circular, or the like. Illustratively, pressure relief body 241 is made of a hard material, and the tensile strength of pressure relief body 241 is 108MPa to 384 MPa. Pressure relief body 241 may be a metal material, such as copper, iron, aluminum, steel, or aluminum alloy.

In the battery cell 20, the first surface 2411 of the pressure relief body 241 may be an outermost surface of the pressure relief body 241, or may be a stepped surface facing the outside of the battery cell 20 at a distance from the outermost surface of the pressure relief body 241. Second surface 2412 of pressure relief body 241 may be the innermost surface of pressure relief body 241, or may be a stepped surface facing the inside of battery cell 20 at a distance from the innermost surface of pressure relief body 241. Illustratively, the first surface 2411 and the second surface 2412 are planar surfaces that are parallel to each other.

In the embodiment of the present application, the number of the pressure relief grooves 242 on the first surface 2411 and the second surface 2412 is not limited, and the number of the pressure relief grooves 242 on the first surface 2411 and the second surface 2412 may be one or more, as long as the pressure relief grooves 242 on the first surface 2411 and the pressure relief grooves 242 on the second surface 2412 correspond to each other one by one. The pressure relief groove 242 may be formed in various manners, such as punch forming, milling forming, and the like, and the embodiment of the present application is not particularly limited thereto. Pressure relief groove 242 may be a linear groove extending along a straight line, or may be a bent groove or an arc groove extending along circumferential direction Y of pressure relief body 241, where the bent groove may be a polygonal groove, for example, a rectangular groove.

The weak portion 2413 is a portion of the pressure relief body 241 located between the two pressure relief grooves 242, that is, a portion of the pressure relief body 241 where the pressure relief grooves 242 are provided remains.

In this embodiment, the first surface 2411 and the second surface 2412 of pressure relief body 241 are both provided with pressure relief groove 242, can obtain lower residual thickness, have reduced the thickness of weak part 2413 for weak part 2413 splits more easily, reduces pressure relief device 24's initiation pressure, makes pressure relief body 241 can in time release pressure, reduces the risk such as battery cell 20 appears catching fire, explosion, effectively improves battery cell 20's security.

In some embodiments, the distance between the first surface 2411 and the second surface 2412 is a first distance, and the ratio of the minimum thickness of the weak portion 2413 to the first distance is 0.12-0.5.

The first distance is the thickness of the pressure relief body 241 in the area between the first surface 2411 and the second surface 2412. The weak portion 2413 may have an equal thickness structure in which any region has an equal thickness, or may have a thickened structure in which a plurality of regions have different thicknesses. The "minimum thickness of the weak portion 2413" does not limit the weak portion 2413 to be a thickened structure. When the weak portion 2413 has an equal thickness structure, the thickness of the weak portion 2413 at any position is the minimum thickness, and the minimum thickness of the weak portion 2413 is the maximum thickness of the weak portion 2413.

If the ratio of the minimum thickness of the weak portion 2413 to the first distance is too small, so that the minimum thickness of the weak portion 2413 is small, the weak portion 2413 may be cracked during the molding process, and even if the weak portion 2413 is not cracked, the strength of the pressure relief body 241 is poor, the weak portion 2413 may be cracked and relieved in a vibration environment or when the pressure or temperature inside the battery cell 20 does not reach a threshold value, which may affect the service life of the battery cell 20. If the ratio of the minimum thickness of the weak portion 2413 to the first distance is too large, the minimum thickness of the weak portion 2413 is relatively large, and accidents such as fire and explosion of the battery cell 20 are caused because the pressure or the temperature of the weak portion 2413 inside the battery cell 20 reaches a threshold value and the pressure is not released, and the pressure is not released in time.

In this embodiment, the ratio of the minimum thickness of the weak portion 2413 to the first distance is set to 0.12-0.5, so that the pressure relief device 24 can timely relieve the pressure when the internal pressure of the battery cell 20 reaches the threshold value, and the pressure relief device 24 can have sufficient strength before relieving the pressure.

In some embodiments, pressure relief groove 242 extends in a circumferential direction Y of pressure relief body 241 and defines a pressure relief portion 2414. The pressure relief portion 2414 is configured to open with the weak portion 2413 as a boundary when the pressure or temperature inside the battery cell 20 reaches a threshold value, to relieve the pressure inside the battery cell 20.

Pressure relief groove 242 may be a closed loop structure extending along circumferential direction Y of pressure relief body 241 and connected end to end, for example, pressure relief groove 242 may be circular, oval, rectangular, etc. The pressure relief groove 242 may also be an open-loop structure extending along the circumferential direction Y of the pressure relief body 241 with a distance from the head to the tail, for example, the pressure relief groove 242 may be "C" -shaped, "Contraband" -shaped, etc.

The pressure relief portion 2414 is an area defined by the pressure relief groove 242 on the pressure relief body 241, and the weak portion 2413 is located at an edge position of the pressure relief portion 2414. When the pressure or temperature inside the battery cell 20 reaches a threshold value, the weak portion 2413 will rupture, so that the pressure relief portion 2414 opens with the weak portion 2413 as a boundary. After the pressure relief portion 2414 is opened, the pressure relief body 241 forms an opening portion at a position corresponding to the pressure relief portion 2414, and the exhaust (gas, electrolyte, etc.) inside the battery cell 20 can be discharged through the opening portion, so as to achieve the purpose of relieving the pressure inside the battery cell 20. In the opening process of the pressure relief portion 2414, the pressure relief portion 2414 may be opened in a manner of being separated from the pressure relief body 241, or may be opened by being turned inside out.

In this embodiment, the pressure relief groove 242 extends along the axial direction of the pressure relief body 241 and defines the pressure relief portion 2414, so that the pressure relief area of the pressure relief device 24 is effectively increased, the pressure relief rate of the pressure relief device 24 is further increased, the risks such as fire and explosion of the single battery 20 are reduced, and the safety of the single battery 20 is improved.

In some embodiments, there is a distance between the two ends of pressure relief groove 242 along the circumferential direction Y of pressure relief body 241.

The pressure relief groove 242 has a distance along both ends of the circumferential direction Y of the pressure relief body 241, that is, the pressure relief groove 242 has a distance at both ends in the extending direction thereof, and it can be understood that the pressure relief groove 242 is an unclosed structure having a distance from the head to the tail.

In this embodiment, there is a distance between two ends of the pressure relief groove 242 in the circumferential direction Y of the pressure relief body 241, and when the weak portion 2413 is opened to relieve pressure, the area between two ends of the pressure relief groove 242 is not opened, so that the pressure relief portion 2414 can be opened in an outward turning manner, and the pressure relief portion 2414 is prevented from falling off and flying out as a whole when relieving pressure.

In some embodiments, the pressure relief groove 242 has a circular arc shape extending along the circumferential direction Y of the pressure relief body 241.

As shown in fig. 2, for example, pressure relief body 241 is circular, and pressure relief groove 242 may be provided coaxially with pressure relief body 241.

Illustratively, the relief groove 242 has a central angle of not less than 180 °. Preferably, the central angle of the pressure relief groove 242 is greater than 270 °.

In the present embodiment, the pressure relief groove 242 is in the shape of a circular arc, and the pressure relief groove 242 of this structure has a regular shape and is easy to machine, so that the pressure relief portion 2414 can be regularly opened when releasing pressure.

In some embodiments, with continued reference to fig. 5, the pressure relief body 241 further has an outer surface 2415 and an inner surface 2416, the outer surface 2415 is disposed opposite to the inner surface 2416 along the thickness direction Z of the pressure relief device 24, and the pressure relief portion 2414 is configured to open in a direction from the inner surface 2416 to the outer surface 2415 when the pressure or temperature inside the battery cell 20 reaches a threshold value. The pressure relief body 241 is provided with a concave portion 2415a, the concave portion 2415a is recessed from the outer surface 2415 in a direction approaching the inner surface 2416 in the thickness direction Z of the pressure relief device 24, and the bottom surface of the concave portion 2415a forms a first surface 2411.

In the battery cell 20, the outer surface 2415 is a surface of the pressure relief body 241 facing the outside of the battery cell 20, and the inner surface 2416 is a surface of the pressure relief body 241 facing the inside of the battery cell 20. The recess 2415a is recessed from the outer surface 2415 in a direction toward the inner surface 2416, and a bottom surface of the recess 2415a forms a first surface 2411, and the first surface 2411 is a step surface of the pressure relief body 241. The shape of the recess 2415a may be various, for example, circular, rectangular, etc.

In the battery cell 20, when the pressure or temperature inside the battery cell 20 reaches a threshold value, the pressure relief portion 2414 will open in a direction from the inner surface 2416 toward the outer surface 2415, that is, the pressure relief portion 2414 will open from the inside to the outside of the battery cell 20.

In the thickness direction Z of the pressure relief body 241, the distance between the outer surface 2415 and the inner surface 2416 is a second distance, and the second distance may be equal to or different from the first distance. If the second distance is different from the first distance, the second distance may be greater than the first distance, or the second distance may be smaller than the first distance.

In this embodiment, the pressure relief body 241 is provided with the recess 2415a, and the recess 2415a can provide an avoiding space for the pressure relief portion 2414 to open outwards, so that even if an obstacle exists on the outer surface 2415 of the pressure relief body 241, the normal opening of the pressure relief portion 2414 can be ensured, and the risk that the pressure relief portion 2414 cannot open due to the obstacle abutting against the outer surface 2415 is reduced.

In some embodiments, a protrusion 2416a protruding from the inner surface 2416 is formed at a position of the pressure relief body 241 corresponding to the recess 2415a, and a surface of the protrusion 2416a facing away from the inner surface 2416 in the thickness direction Z of the pressure relief device 24 forms a second surface 2412.

The shape of the protrusion 2416a may be adapted to the shape of the recess 2415 a. For example, the concave portion 2415a may be circular, and the convex portion 2416a may be correspondingly circular; for another example, the concave portion 2415a may be rectangular, and the convex portion 2416a may be correspondingly rectangular. The convex portion 2416a has an outer peripheral surface connected between the second surface 2412 and the inner surface 2416, and the outer peripheral surface is located at the outer periphery of the concave portion 2415 a. For example, the concave portion 2415a and the convex portion 2416a are both circular, the concave portion 2415a and the convex portion 2416a are provided coaxially, and the diameter of the outer peripheral surface of the convex portion 2416a is larger than the diameter of the concave portion 2415 a.

In actual production, a concave portion 2415a may be formed on one side of the pressure relief body 241 by stamping, and a convex portion 2416a may be formed on the other side of the pressure relief body 241 correspondingly.

In this embodiment, a convex portion 2416a protruding from the inner surface 2416 is formed at a position of the pressure relief body 241 corresponding to the concave portion 2415a, and the provision of the convex portion 2416a can increase the strength of the area of the pressure relief body 241 where the concave portion 2415a is provided, thereby avoiding the problem of local strength shortage due to the provision of the concave portion 2415a in the pressure relief body 241.

In some embodiments, referring to fig. 6, fig. 6 is a cross-sectional view taken along a line a-a of the pressure relief device 24 shown in fig. 4, a welding groove 2415b is further formed on the outer surface 2415, a protrusion 2416b protruding from the inner surface 2416 is formed at a position of the pressure relief body 241 corresponding to the welding groove 2415b, and both the welding groove 2415b and the protrusion 2416b are located at the periphery of the protrusion 2416 a. The protrusion 2416b is for abutting and welding with the current collecting member 26.

Illustratively, the weld groove 2415b and the protrusion 2416b are each an annular structure disposed around the protrusion 2416 a.

In this embodiment, the pressure relief body 241 may serve as an end cap 23 in the battery cell 20 to cover the opening of the case 22. When the pressure relief body 241 is welded to the current collecting member 26, the pressure relief body 241 may be welded in the area of the welding groove 2415b so that the protrusion 2416b is welded to the current collecting member 26, and a welding mark formed by welding the protrusion 2416b to the current collecting member 26 is formed in the welding groove 2415 b.

In some embodiments, referring to fig. 7 and 8, fig. 7 is a partial enlarged view of a pressure relief device 24 according to some embodiments of the present disclosure, fig. 8 is a partial enlarged view of a pressure relief device 24 according to other embodiments of the present disclosure, and the pressure relief groove 242 includes a groove bottom surface 2422 and two groove side surfaces 2421. Along the width direction X of the pressure relief groove 242, two groove side surfaces 2421 are disposed facing each other. The slot bottom 2422 is connected to the two slot sides 2421. Wherein a region between the groove bottom surfaces 2422 of the two relief grooves 242 forms a weak portion 2413.

The two groove sides 2421 of the pressure relief groove 242 may be parallel to each other or may be inclined to each other. The groove bottom surface 2422 of the pressure relief groove 242 may be a flat surface or a curved surface.

In the present embodiment, the pressure relief groove 242 is easy to machine, and the pressure relief groove 242 may be formed by press molding.

In some embodiments, referring to fig. 7, the groove bottom surface 2422 is a circular arc surface recessed along the depth direction of the pressure relief groove 242.

It is understood that, for the pressure relief groove 242 disposed on the first surface 2411, the depth direction of the pressure relief groove 242 is the direction in which the first surface 2411 points to the second surface 2412. For the pressure relief groove 242 disposed on the second surface 2412, the depth direction of the pressure relief groove 242 is the direction in which the second surface 2412 points to the first surface 2411.

In the present embodiment, the distance between the arc apexes of the groove bottom surfaces 2422 of the two relief grooves 242 is the minimum thickness of the weak portion 2413.

Illustratively, slot bottom surface 2422 is tangent to both slot sides 2421 of pressure relief slot 242.

In this embodiment, the groove bottom surface 2422 is an arc surface recessed in the depth direction of the pressure relief groove 242, so that the weak portion 2413 has a structure with a thickness gradually decreasing from two sides to the middle position, the weak portion 2413 can be ruptured from the middle weakest position during pressure relief, the weak portion 2413 can be ruptured more easily, and it is ensured that the weak portion 2413 can be ruptured in time to relieve pressure when the pressure or temperature of the pressure relief device 24 inside the battery cell 20 reaches a threshold value.

In some embodiments, referring to fig. 8, the slot bottom surface 2422 includes a bottom planar surface 2422a and an arcuate chamfer surface 2422b, the bottom planar surface 2422a and each slot side surface 2421 being connected by an arcuate chamfer surface 2422 b.

In the present embodiment, the distance between the bottom planes 2422a of the two pressure relief grooves 242 is the minimum thickness of the weak portion 2413.

Illustratively, the bottom plane 2422a and the slot side surface 2421 are both tangent to the arcuate chamfer surface 2422 b. In the relief groove 242, two arc-shaped chamfered surfaces 2422b connected to the two groove side surfaces 2421 are symmetrically provided in the width direction X of the relief groove 242.

In the present embodiment, the bottom plane 2422a is connected to each groove side surface 2421 through an arc-shaped chamfer surface 2422b, so that the groove side surfaces 2421 and the bottom plane 2422a are easily machined and formed, and the structure makes the middle area of the weak portion 2413 (the area where the weak portion 2413 corresponds to the bottom plane 2422 a) be weakest, so that the weak portion 2413 is more easily cracked, and the weak portion 2413 is guaranteed to be cracked and released in time when the pressure or temperature inside the battery cell 20 reaches a threshold value.

In some embodiments, with continued reference to fig. 7 and 8, the distance between the two groove sides 2421 decreases along the depth direction of the pressure relief groove 242.

Illustratively, both groove side surfaces 2421 of the pressure relief groove 242 are inclined planes, and the two groove side surfaces 2421 are symmetrically arranged along the width direction X of the pressure relief groove 242.

In the present embodiment, the distance between the two groove side surfaces 2421 is gradually reduced in the depth direction of the pressure relief groove 242, and this structure is effective to reduce the width of the weak portion 2413, so that the weak portion 2413 is more likely to be ruptured when the pressure or temperature inside the battery cell 20 reaches a threshold value.

In some embodiments, referring to fig. 9, fig. 9 is a partial cross-sectional view of a pressure relief device 24 according to other embodiments of the present disclosure, in which an oxidation-resistant layer 2417 is formed on a surface of a pressure relief body 241, and the oxidation-resistant layer 2417 is disposed in an area where a pressure relief groove 242 is disposed and extends along a groove wall surface of the pressure relief groove 242.

For example, the oxidation resistant layer 2417 may be a metal plating on the surface of the pressure relief body 241. For example, the pressure relief body 241 is a steel layer, and the oxidation resistant layer 2417 is a nickel layer plated on the pressure relief body 241.

Anti-oxidation layer 2417 protects pressure relief body 241 from oxidation. Of course, since the oxidation-resistant layer 2417 is disposed in the area where the pressure relief groove 242 is disposed and extends along the groove wall surface of the pressure relief groove 242, the oxidation-resistant layer 2417 can also protect the area where the pressure relief body 241 is disposed and the pressure relief groove 242, and reduce the risk that the strength of the weak portion 2413 is weakened due to oxidation of the pressure relief body 241 in the area where the pressure relief groove 242 is disposed.

In some embodiments, the thickness of the oxidation resistant layer 2417 in the region of the pressure relief grooves 242 is less than the thickness of the oxidation resistant layer 2417 in the remaining region.

The remaining area refers to the area of pressure relief body 241 other than the area of pressure relief groove 242.

Illustratively, the thickness of the oxidation resistant layer 2417 in the region corresponding to the groove bottom surface 2422 of the pressure relief groove 242 is greater than the thickness of the oxidation resistant layer 2417 in the region corresponding to the groove side surface 2421 of the pressure relief groove 242, so as to improve the oxidation resistance of the weak portion 2413.

In this embodiment, the thickness of the oxidation resistant layer 2417 in the area of the pressure relief groove 242 is smaller than the thickness of the oxidation resistant layer 2417 in the remaining area, so as to reduce the influence of the oxidation resistant layer 2417 in the area of the pressure relief groove 242 on the weak portion 2413, and ensure that the weak portion 2413 can be ruptured to relieve pressure in time when the pressure or temperature inside the battery cell 20 reaches a threshold value.

The embodiment of the application provides a battery cell 20, which comprises an electrode assembly 21 and a shell, wherein the shell is used for accommodating the electrode assembly 21. Wherein the housing includes a pressure relief device 24 as provided in any of the above embodiments.

In some embodiments, the case further includes a case 22, the case 22 is used for accommodating the electrode assembly 21, the case 22 has an opening, and the pressure relief body 241 is used for covering the opening.

It will be appreciated that in this embodiment, pressure relief body 241 is end cap 23.

The embodiment of the application provides a battery 100, which comprises a box body 10 and a battery cell 20 provided by any one of the above embodiments, wherein the box body 10 is used for accommodating the battery cell 20.

The embodiment of the present application provides an electric device, including the battery 100 provided in any one of the above embodiments.

In addition, referring to fig. 4 and fig. 5, an embodiment of the present disclosure provides a pressure relief device 24 for covering an opening of a housing 22 of a battery cell 20, the pressure relief device 24 includes a pressure relief body 241 and two pressure relief grooves 242, the pressure relief body 241 is circular and has a first surface 2411 and a second surface 2412 disposed opposite to each other along a thickness direction Z thereof. The two pressure relief grooves 242 are oppositely arranged along the thickness direction Z of the pressure relief body 241 and are respectively arranged on the first surface 2411 and the second surface 2412, a weak portion 2413 is formed between the two pressure relief grooves 242, the pressure relief grooves 242 extend along the circumferential direction Y of the pressure relief body 241 and define a pressure relief portion 2414, a distance exists between two ends of the pressure relief groove 242 along the circumferential direction Y of the pressure relief body 241, and the pressure relief portion 2414 is configured to open with the weak portion 2413 as a boundary when the pressure or temperature inside the battery cell 20 reaches a threshold value, so as to relieve the pressure inside the battery cell 20.

In such pressure relief device 24, the first surface 2411 and the second surface 2412 of pressure relief body 241 are both provided with pressure relief groove 242, can obtain lower residual thickness, have reduced the thickness of weak part 2413 for weak part 2413 splits more easily, reduces pressure relief device 24's initiation pressure, makes pressure relief body 241 can in time release pressure, reduces the risk such as battery cell 20 appears catching fire, explosion, effectively improves battery cell 20's security. In addition, when the weak portion 2413 is opened to release the pressure, the area between the two ends of the pressure release groove 242 is not opened, so that the pressure release portion 2414 can be opened in an outward-turning manner, and the pressure release portion 2414 is prevented from being entirely detached and flying out during pressure release.

Referring to fig. 10, fig. 10 is a flowchart of a method for manufacturing a pressure relief device 24 according to some embodiments of the present disclosure, where the method for manufacturing a pressure relief device 24 includes:

s100: providing a pressure relief body 241, wherein the pressure relief body 241 is provided with a first surface 2411 and a second surface 2412 which are oppositely arranged along the thickness direction Z;

s200: the pressure relief groove 242 is formed on the first surface 2411 and the second surface 2412 of the pressure relief body 241, such that the pressure relief groove 242 on the first surface 2411 and the pressure relief groove 242 on the second surface 2412 are disposed opposite to each other in the thickness direction Z of the pressure relief device 24, a weak portion 2413 is formed between the pressure relief groove 242 on the first surface 2411 and the pressure relief groove 242 on the second surface 2412, and the weak portion 2413 is configured to be ruptured when the pressure or the temperature inside the battery cell 20 reaches a threshold value, so as to relieve the pressure inside the battery cell 20.

It should be noted that, for the related structure of the pressure relief device 24 manufactured by the manufacturing method provided in the foregoing embodiments, reference may be made to the pressure relief device 24 provided in the foregoing embodiments, and details are not described herein.

Referring to fig. 11, fig. 11 is a schematic block diagram of an apparatus 2000 for manufacturing a pressure relief device 24 according to some embodiments of the present disclosure, and an apparatus 2000 for manufacturing a pressure relief device 24 according to some embodiments of the present disclosure is also provided, where the apparatus 2000 includes a providing device 2100 and a processing device 2200.

Device 2100 is provided for providing a pressure relief body 241, pressure relief body 241 having a first surface 2411 and a second surface 2412 disposed opposite along a thickness direction Z thereof. The processing apparatus 2200 is configured to process the pressure relief grooves 242 on the first surface 2411 and the second surface 2412 such that the pressure relief grooves 242 on the first surface 2411 and the pressure relief grooves 242 on the second surface 2412 are disposed opposite to each other in the thickness direction Z of the pressure relief apparatus 24, and a weak portion 2413 is formed between the pressure relief grooves 242 on the first surface 2411 and the pressure relief grooves 242 on the second surface 2412, and the weak portion 2413 is configured to be ruptured when the pressure or the temperature inside the battery cell 20 reaches a threshold value, so as to relieve the pressure inside the battery cell 20.

It should be noted that, with reference to the related structure of the pressure relief device 24 manufactured by the manufacturing apparatus 2000 provided in the foregoing embodiments, reference may be made to the pressure relief device 24 provided in each of the foregoing embodiments, and details are not described herein again.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The above embodiments are merely for illustrating the technical solutions of the present application and are not intended to limit the present application, and those skilled in the art can make various modifications and variations of the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pressure relief device for a battery cell, comprising:

the pressure relief body is provided with a first surface and a second surface which are oppositely arranged along the thickness direction;

two pressure relief grooves, set up along the thickness direction is relative, and set up respectively in the first surface and the second surface, form weak part between two the pressure relief grooves, the weak part is configured to split when the pressure or the temperature in the battery monomer reach the threshold value, in order to bleed the pressure in the battery monomer.

2. The pressure relief device according to claim 1, wherein a distance between said first surface and said second surface is a first distance, and a ratio of a minimum thickness of said weakened portion to said first distance is 0.12-0.5.

3. The pressure relief device of claim 1, wherein said pressure relief groove extends circumferentially of said pressure relief body and defines a pressure relief portion;

the pressure relief portion is configured to open with the weak portion as a boundary when a pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell.

4. The pressure relief device according to claim 3, wherein said pressure relief groove has a distance between its ends along a circumferential direction of said pressure relief body.

5. The pressure relief device according to claim 3, wherein said pressure relief groove is in the shape of a circular arc extending in the circumferential direction of said pressure relief body.

6. The pressure relief device according to claim 3, wherein said pressure relief body further has an outer surface and an inner surface, said outer surface being disposed opposite to said inner surface in said thickness direction, said pressure relief portion being configured to open in a direction from said inner surface to said outer surface when a pressure or temperature inside the battery cell reaches a threshold value;

the pressure relief body is provided with a concave portion, the concave portion is recessed from the outer surface along the direction close to the inner surface along the thickness direction, and the bottom surface of the concave portion forms the first surface.

7. The pressure relief device according to claim 6, wherein a protrusion protruding from said inner surface is formed at a position of said pressure relief body corresponding to said recess, and a surface of said protrusion facing away from said inner surface forms said second surface along said thickness direction.

8. The pressure relief device according to any of claims 1-7, wherein said pressure relief groove comprises:

two groove side surfaces which are arranged along the width direction of the pressure relief groove and face each other;

a groove bottom surface connected to the two groove side surfaces;

wherein an area between groove bottoms of the two relief grooves forms the weak portion.

9. The pressure relief device according to claim 8, wherein said groove bottom surface is a circular arc surface recessed in a depth direction of said pressure relief groove.

10. The pressure relief device according to claim 8, wherein said tank bottom surface comprises a bottom flat surface and an arcuate chamfered surface, said bottom flat surface being connected to each of said tank side surfaces by one of said arcuate chamfered surfaces.

11. The pressure relief device according to claim 8, wherein the distance between two sides of said groove decreases gradually along the depth direction of said pressure relief groove.

12. The pressure relief device according to any of claims 1-7, wherein an oxidation resistant layer is formed on a surface layer of said pressure relief body, and said oxidation resistant layer is extended along a groove wall surface of said pressure relief groove in an area where said pressure relief groove is disposed.

13. The pressure relief device according to claim 12, wherein a thickness of said oxidation resistant layer in a region of said pressure relief groove is less than a thickness of said oxidation resistant layer in a remaining region.

14. A battery cell, comprising;

an electrode assembly;

a housing for housing the electrode assembly, the housing comprising the pressure relief device of any one of claims 1-13.

15. The battery cell of claim 14, wherein the housing further comprises a casing configured to house the electrode assembly, the casing having an opening, and the pressure relief body configured to cover the opening.

16. A battery, comprising:

the battery cell of claim 14 or 15;

and the box body is used for accommodating the battery monomer.

17. An electrical device comprising the battery of claim 16.