CN217719870U

CN217719870U - Pressure relief device, shell, battery monomer, battery and consumer

Info

Publication number: CN217719870U
Application number: CN202221384974.0U
Authority: CN
Inventors: 陈小波; 顾明光
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2022-11-01
Anticipated expiration: 2032-06-02

Abstract

The embodiment of the application provides a pressure relief device, a shell, a single battery, a battery and electric equipment, and belongs to the technical field of batteries. Wherein, pressure relief device is used for the battery monomer, and pressure relief device part is formed with the weak area, and the weak area is used for breaking when battery monomer discharge pressure, and the thickness in weak area is a, and the hardness in weak area is A, satisfies: a/a is more than or equal to 5HBW/mm and less than or equal to 10000HBW/mm. The ratio of the hardness of the weak area to the thickness of the weak area is set within a reasonable range, the weak area has enough strength in the normal use process of the single battery, the pressure relief device is not easy to break at the weak area, the service life of the single battery is prolonged, the pressure relief device can timely relieve pressure through the weak area when the single battery is out of control due to heat, the risks of fire and explosion of the single battery are reduced, and the safety of the single battery is improved.

Description

Pressure relief device, shell, battery monomer, battery and consumer

Technical Field

The application relates to the technical field of batteries, in particular to a pressure relief device, a shell, 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.

The battery cell serves as an energy storage element, and generally, an electrode assembly and an electrolyte chemically react with each other to output electric energy. In addition to improving the performance of the battery cell, safety is also a concern in the development of battery technology. Therefore, how to improve the safety of the battery cell is an urgent problem to be solved in the battery technology.

SUMMERY OF THE UTILITY MODEL

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

In a first aspect, an embodiment of the present application provides a pressure relief device, which is used for a single battery, wherein a weak area is locally formed on the pressure relief device, the weak area is used for breaking when the single battery releases pressure, the thickness of the weak area is a, and the hardness of the weak area is a, which satisfies the following requirements: 5HBW/mm is less than or equal to A/a is less than or equal to 10000HBW/mm.

Among the above-mentioned technical scheme, not only consider the influence of the thickness in weak area to pressure relief device's performance, still consider the influence of the hardness in weak area to pressure relief device's performance, set up the ratio of the hardness in weak area and the thickness in weak area in reasonable scope, can enough make the weak area have sufficient intensity in the battery monomer normal use in-process, pressure relief device is difficult for breaking taking place in weak area position, improve the free life of battery, can make pressure relief device can in time release pressure through the weak area when the battery monomer thermal runaway again, reduce the free risk that takes place to catch fire, the explosion of battery, improve the free security of battery.

In some embodiments, 190HBW/mm ≦ A/a ≦ 4000HBW/mm. Therefore, the pressure relief device is better in performance, and the weak area is guaranteed to be broken and relieved in time when the single battery is out of control due to heat while the weak area is guaranteed to have enough strength in the normal use process of the single battery. On the premise of ensuring the safety of the battery monomer, the service life of the battery monomer is prolonged.

In some embodiments, 8HBW ≦ A ≦ 200HBW.

In some embodiments, 0.02mm ≦ a ≦ 1.6mm.

In some embodiments, the pressure relief device comprises a non-weakened area connected around the weakened area, the non-weakened area having a thickness b, such that: a is less than b. The thickness of the weak area is set to be smaller than that of the non-weak area, so that the weak area is easier to break than the non-weak area, and the pressure relief device is guaranteed to break and relieve pressure at the position of the weak area when the single battery is out of control due to thermal runaway.

In some embodiments, 0.05 ≦ a/b ≦ 0.95. The ratio of the thickness of the weak area to the thickness of the non-weak area is set to be 0.05-0.95, so that the probability of breakage of the weak area in the normal use process of the battery monomer can be reduced, and the probability of accidents such as fire and explosion and the like when the battery monomer is out of control due to heat can be reduced.

In some embodiments, 0.12 ≦ a/b ≦ 0.8.

In some embodiments, the non-weakened area has a hardness of B, satisfying: b is less than A. The hardness of the weak area is higher than that of the non-weak area, which is equivalent to improving the hardness of the weak area, improving the strength of the weak area and reducing the risk of the weak area cracking in the normal use process of the battery monomer.

In some embodiments, A/B ≦ 3. The hardness in weak area and the hardness in non-weak area's ratio is big more, and the weak area is difficult to break more, and if both ratios are too big, the condition that the weak area can't in time break the pressure release when battery monomer thermal runaway can appear, consequently, sets up the hardness in the weak area and the hardness in non-weak area to be not more than 3, guarantees that the weak area can in time break the pressure release when battery monomer thermal runaway, improves battery monomer's security.

In some embodiments, the non-weakened areas are directly connected to the weakened areas. Simple structure and easy molding.

In some embodiments, the pressure relief device is provided with a groove, the pressure relief device forms a connection region where the groove is provided, the non-weakened region is connected to the periphery of the connection region, and the connection region locally forms the weakened region. Thus, the connecting area is thinner than the weak area, and the weak area is more easily formed at the connecting area.

In some embodiments, the area of weakness is integrally formed with the non-area of weakness. The forming difficulty of the pressure relief device is reduced, the economy is good, the weak area and the non-weak area have good integrity, and the strength of the weak area can be improved.

In some embodiments, the pressure relief device includes a vent portion, the area of weakness extending along an edge of the vent portion, the vent portion configured to open bounded by the area of weakness. Therefore, the pressure relief area of the pressure relief device is increased, and the pressure relief efficiency is improved. In some embodiments, the pressure relief device is provided with a pressure relief groove, the pressure relief device forming a weakened area at the location where the pressure relief groove is provided. The weak area is formed by arranging the pressure relief groove on the pressure relief device, and the forming mode of the weak area is simple.

In some embodiments, the surface layer of the pressure relief device is formed with an oxidation resistant layer, and the oxidation resistant layer is arranged along the groove wall surface of the pressure relief groove in the area where the pressure relief groove is arranged. The antioxidation layer protects the pressure relief device and reduces the risk that the pressure relief device is oxidized. Because the antioxidation layer is arranged along the groove wall surface of the pressure relief groove in the region where the pressure relief groove is arranged, the antioxidation layer can play a good role in protecting the region where the pressure relief device is arranged, and the risk that the strength of a weak area is weakened because the pressure relief device is oxidized in the region where the pressure relief groove is arranged is reduced.

In some embodiments, the pressure relief device comprises a non-weakened area connected around the weakened area, the thickness of the oxidation resistant layer in the weakened area is d, and the thickness of the oxidation resistant layer in the non-weakened area is e, and the following conditions are satisfied: d is less than e. The influence of the oxidation resistant layer on the weak area is reduced, and the weak area can be broken and decompressed in time when the battery monomer is out of control due to heat.

In some embodiments, the pressure relief device includes a plurality of walls that collectively enclose a receiving space for receiving an electrode assembly of the battery cell, at least one wall being formed with a weakened area. The pressure relief device can provide accommodation space for the electrode assembly, so that the pressure relief device has the accommodation function of accommodating the battery cell and also has the pressure relief function.

In some embodiments, the plurality of walls includes a bottom wall and a plurality of side walls, the plurality of side walls are arranged around the bottom wall, the plurality of side walls and the bottom wall jointly enclose to define a containing space, and the pressure relief device forms an opening at one end opposite to the bottom wall; the bottom wall is formed with a weakened area; and/or at least one of the sidewalls is formed with a weakened area.

In some embodiments, the pressure relief device is a plate-like structure. The pressure relief device has simple structure and is easy to mold and manufacture.

In a second aspect, embodiments of the present application provide a housing including a pressure relief device as provided in any of the embodiments of the first aspect.

In a third aspect, an embodiment of the present application provides a battery cell, which includes an electrode assembly and a case provided in any one of the embodiments of the second aspect, wherein the electrode assembly is accommodated in the case.

In a fourth aspect, an embodiment of the present application provides a battery, which includes a case and a battery cell provided in any one of embodiments of the third aspect, where the battery cell is accommodated in the case.

In a fifth aspect, an embodiment of the present application provides an electric device, which includes the battery provided in any one of the embodiments of the fourth 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 structural diagram of a vehicle provided in 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 top view of a pressure relief device provided in accordance with certain embodiments of the present application;

FIG. 5 isbase:Sub>A cross-sectional view A-A of the pressure relief device shown in FIG. 4;

FIG. 6 is a top view of a pressure relief device according to other embodiments of the present application;

FIG. 7 is a cross-sectional view B-B of the pressure relief device shown in FIG. 6;

FIG. 8 is a top view of a pressure relief device according to still other embodiments of the present application;

FIG. 9 is a cross-sectional C-C view of the pressure relief device shown in FIG. 8;

FIG. 10 is a top view of a pressure relief device according to still other embodiments of the present application;

FIG. 11 is a top view of a pressure relief device according to another embodiment of the present application;

FIG. 12 is an enlarged partial view of the pressure relief device shown in FIG. 5 at D;

FIG. 13 is an enlarged view of a portion of the pressure relief device shown in FIG. 7 at E;

FIG. 14 is an enlarged fragmentary view of the pressure relief device shown in FIG. 9 at F;

FIG. 15 is an isometric view of a pressure relief device provided by some embodiments of the present application;

FIG. 16 is a cross-sectional view of the pressure relief device shown in FIG. 15;

FIG. 17 is an isometric view of a pressure relief device provided in accordance with still further embodiments of the present application;

FIG. 18 is a schematic structural view of a housing provided in accordance with some embodiments of the present application;

fig. 19 is a schematic structural diagram of a housing according to another embodiment of the present application.

An icon: 1-a housing; 11-a housing; 12-an end cap; 121-positive electrode terminal; 122-negative electrode terminal; 13-a pressure relief device; 131-a weak area; 1311-first weakened section; 1312-a second weak section; 1313-third weakened section; 132-non-weakened areas; 133-grooves; 134-a linker region; 135-a pressure relief portion; 136-pressure relief groove; 137-a first surface; 138-a second surface; 139-antioxidation layer; 140-a containment space; 141-a bottom wall; 142-a side wall; 2-an electrode assembly; 21-positive tab; 22-negative tab; 10-a battery cell; 20-a box body; 201-a first portion; 202-a second portion; 100-a battery; 200-a controller; 300-a motor; 1000-a vehicle; 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 obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to 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 should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "attached" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; 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 the case may be.

The term "and/or" in this application is only one kind of association relationship describing the association object, and means that there may be three kinds of relationships, for example, a and/or B, and 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 a packaging 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 electrode plate, a negative electrode plate and a separation film. 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 comprises a positive pole current collector and a positive pole active substance layer, wherein the positive pole active substance layer is coated on the surface of the positive pole current collector, the positive pole current collector which is not coated with the positive pole active substance layer protrudes out of the positive pole current collector which is coated with the positive pole active substance layer, and the positive pole current collector which is not coated with the positive pole active substance layer is used as a positive pole lug. 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 comprises a negative pole current collector and a negative pole active substance layer, wherein the negative pole active substance layer is coated on the surface of the negative pole current collector, the negative pole current collector which is not coated with the negative pole active substance layer protrudes out of the negative pole current collector which is coated with the negative pole active substance layer, and the negative pole current collector which is not coated with the negative pole active substance layer is used as a negative pole lug. 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, can set up pressure relief device in the battery monomer, be formed with the weak area among the pressure relief device, when the free thermal runaway of battery, come the inside pressure of battery monomer of bleeder through the weak area to improve the free security of battery.

The inventor notices that in order to ensure that the pressure relief device can timely relieve the pressure when the single battery is out of control due to heat, the thickness of the weak area can be set to be smaller, but the weak area is easy to break in a vibration environment or due to long-term change of the internal pressure of the single battery in the normal use process of the single battery, and the service life of the single battery is shorter. In order to ensure that the single battery has longer service life, the thickness of the weak area can be set to be larger, but the situation that the pressure relief of the weak area is not timely when the single battery is out of control due to heat easily occurs, accidents such as fire and explosion of the single battery easily occur, and the safety of the single battery is poorer.

In view of this, the embodiment of the present application provides a pressure relief device, and a ratio of the hardness of the weak area to the thickness of the weak area is set to be 5HBW/mm to 10000HBW/mm.

In the pressure relief device, the influence of the thickness of the weak area on the performance of the pressure relief device is considered, the influence of the hardness of the weak area on the performance of the pressure relief device is also considered, the ratio of the hardness of the weak area to the thickness of the weak area is set within a reasonable range, the weak area has enough strength in the normal use process of the single battery, the pressure relief device is not prone to rupture at the position of the weak area, the service life of the single battery is prolonged, the pressure relief device can timely relieve pressure through the weak area when the single battery is out of control due to heat, the risks of fire and explosion of the single battery are reduced, and the safety of the single battery is improved.

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 device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool 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; the 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 tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and electric 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. The battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail 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 not only serve as an operating power source of the vehicle 1000, but also serve 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. The battery 100 includes a battery cell 10 and a case 20, and the battery cell 10 is accommodated in the case 20.

The case 20 is a component for accommodating the battery cell 10, the case 20 provides an accommodating space for the battery cell 10, and the case 20 may have various structures. In some embodiments, the case 20 may include a first portion 201 and a second portion 202, and the first portion 201 and the second portion 202 are mutually covered to define a receiving space for receiving the battery cell 10. The first portion 201 and the second portion 202 may be in various shapes, such as a rectangular parallelepiped, a cylinder, and the like. The first portion 201 may be a hollow structure with one side open, the second portion 202 may be a hollow structure with one side open, and the open side of the second portion 202 is closed to the open side of the first portion 201 to form the case 20 having the receiving space. The first portion 201 may have a hollow structure with one side open, the second portion 202 may have a plate-like structure, and the second portion 202 may cover the open side of the first portion 201 to form the case 20 having the housing space. The first portion 201 and the second portion 202 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 10 may be provided. If there are a plurality of battery cells 10, the plurality of battery cells 10 may be connected in series, in parallel, or in series-parallel, where the series-parallel refers to that the plurality of battery cells 10 are connected in series or in parallel. A plurality of battery cells 10 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 case 20. Or all the single batteries 10 can be directly connected in series or in parallel or in series-parallel, and the whole formed by all the single batteries 10 is accommodated in the box 20.

In some embodiments, the battery 100 may further include a bus member, and the plurality of battery cells 10 may be electrically connected to each other through the bus member, so as to connect the plurality of battery cells 10 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 10 according to some embodiments of the present disclosure. The battery cell 10 may include a case 1 and an electrode assembly 2.

The case 1 is a member for accommodating the electrode assembly 2. The housing 1 may be in various shapes, such as a cylinder, a rectangular parallelepiped, etc. The housing 1 may include a case 11 and an end cap 12.

The housing 11 may be a hollow structure with an opening formed at one end, and the housing 11 may also be a hollow structure with openings formed at the opposite ends. The material of the housing 11 may be various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

The end cap 12 is a member that closes the opening of the case 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 defines a sealed space for accommodating the electrode assembly 2, the electrolyte, and other components together with the case 11. The end cap 12 may be connected to the housing 11 by welding or crimping to close the opening of the housing 11. The shape of the end cap 12 may be adapted to the shape of the casing 1, for example, the casing 11 is a rectangular parallelepiped structure, the end cap 12 is a rectangular plate structure adapted to the casing 1, and for example, the casing 11 is a cylinder, and the end cap 12 is a circular plate structure adapted to the casing 11. The end cap 12 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, and the like.

In the battery cell 10, the number of the end caps 12 may be one or two. In the embodiment that the housing 11 is a hollow structure with two open ends, two end covers 12 may be correspondingly disposed, the two end covers 12 respectively close the two open ends of the housing 11, and the two end covers 12 and the housing 11 together define a sealed space. In the embodiment that the housing 11 is a hollow structure with an opening formed at one end, one end cap 12 may be correspondingly arranged, the end cap 12 closes the opening at one end of the housing 11, and one end cap 12 and the housing 11 jointly define a sealed space.

The electrode assembly 2 is a component of the battery cell 10 where electrochemical reactions occur. The electrode assembly 2 may include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 2 may have a winding type structure formed by winding a positive electrode sheet, a separator, and a negative electrode sheet, or a lamination type structure formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet. The electrode assembly 2 has a positive electrode tab 21 and a negative electrode tab 22, and the positive electrode tab 21 may be a portion of the positive electrode sheet not coated with the positive electrode active material layer, and the negative electrode tab 22 may be a portion of the negative electrode sheet not coated with the negative electrode active material layer.

The battery cell 10 may further include electrode terminals disposed on the end cap 12, the electrode terminals being for electrical connection with tabs of the electrode assembly 2 to output electric power of the battery cell 10. The electrode terminal and the tab may be directly connected, for example, the electrode terminal and the tab are directly welded. The electrode terminals and the tabs may also be indirectly connected, for example, by a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, or the like.

As shown in fig. 3, taking a hollow structure with an opening formed at one end of the case 11 as an example, two electrode terminals may be disposed on the end cap 12, where the two electrode terminals are a positive electrode terminal 121 and a negative electrode terminal 122, respectively, the positive electrode terminal 121 is electrically connected to the positive tab 21, and the negative electrode terminal 122 is electrically connected to the negative tab 22.

A pressure relief device 13 (not shown in fig. 3) may be provided in the battery cell 10, and the pressure relief device 13 is a component that relieves the pressure inside the battery cell 10. When the pressure or temperature inside the battery cell 10 reaches a threshold value, the pressure inside the battery cell 10 is discharged through the pressure relief device 13. The specific structure of the pressure relief device 13 will be explained in detail below with reference to the drawings.

Referring to fig. 4 and 5, fig. 4 isbase:Sub>A top view ofbase:Sub>A pressure relief device 13 according to some embodiments of the present disclosure, and fig. 5 isbase:Sub>A cross-sectional viewbase:Sub>A-base:Sub>A of the pressure relief device 13 shown in fig. 4. The embodiment of the application provides a pressure relief device 13 for battery monomer 10, pressure relief device 13 is local to be formed with weak area 131, and weak area 131 is used for breaking when battery monomer 10 releases pressure, and the thickness of weak area 131 is a, and the hardness of weak area 131 is A, satisfies: a/a is more than or equal to 5HBW/mm and less than or equal to 10000HBW/mm.

The pressure relief device 13 may be the end cap 12 itself or the housing 11 itself. The pressure relief device 13 may also be a separate component disposed on the housing 11 and/or the end cap 12, for example, the pressure relief device 13 is a rupture disk disposed on the end cap 12 and/or the housing 11. The pressure relief device 13 may be made of metal, such as copper, iron, aluminum, steel, aluminum alloy, etc.; the pressure relief device 13 may also be a non-metallic material, such as plastic.

The weakened area 131 is a portion of the pressure relief device 13 that is weaker than other areas, and in the pressure relief device 13, the weakened area 131 is more easily ruptured than other areas. When the internal pressure of the single battery 10 reaches the relief pressure, which requires the relief pressure, the weak region 131 can be broken, so that the exhaust inside the single battery 10 can be discharged, thereby achieving the purpose of relieving the internal pressure of the single battery 10. The thickness of the weakened area 131 may be uniform or non-uniform. If the thickness of the weak area 131 is uniform, the thickness measured at any position of the weak area 131 is the thickness of the weak area 131; if the thickness of the weak region 131 is non-uniform, the thickness measured at the thinnest position of the weak region 131 is the thickness of the weak region 131, i.e., a is the minimum thickness of the weak region 131.

The weakened area 131 may be a variety of shapes, such as rectangular, circular, oval, annular, U-shaped, C-shaped, H-shaped, and the like. If the weak area 131 is annular, the weak area 131 is a closed structure extending along a closed track connected from the head to the tail, and the annular shape may be a rectangular ring, a circular ring, or the like.

The hardness of the weakened area 131 is brinell hardness in HBW. The measurement method of Brinell hardness can be implemented by referring to the measurement principle in GB/T23.1-2018. In the actual measurement process, the hardness of the weak area 131 can be obtained by measurement on any surface in the thickness direction Z of the weak area 131. Taking the end cap 12 of the battery cell 10 as the pressure relief device 13 for example, the hardness of the weak region 131 may be measured on the outer surface of the weak region 131, and the hardness of the weak region 131 may also be measured on the inner surface of the weak region 131. In the battery cell 10, along the thickness direction Z of the weak region 131, the inner surface of the weak region 131 is a surface of the weak region 131 facing the inside of the battery cell 10, and the outer surface of the weak region 131 is a surface of the weak region 131 facing the outside of the battery cell 10.

A/a may be any value between 5HBW/mm and 10000HBW/mm, for example, 5HBW/mm, 50HBW/mm, 100HBW/mm, 190HBW/mm, 500HBW/mm, 1000HBW/mm, 4000HBW/mm, 8000HBW/mm, 10000HBW/mm, or the like.

To test the effect of the ratio of the stiffness of the weakened area 131 to the thickness of the weakened area 131 on the performance of the pressure relief device 13, a plurality of groups of battery cells 10 were tested, and the test results are shown in table one:

watch 1

When a/a is greater than 10000HBW/mm, the weak area 131 is thin and has high hardness, so that the weak area 131 is very fragile and easy to break, the weak area 131 breaks in a normal service cycle of the battery cell 10, and the service life of the battery cell 10 is short. When A/a is less than 5HBW/mm, the weak area 131 is thick and has low hardness, and when the battery cell 10 is out of control due to heat, the weak area 131 is deformed and then elongated and is not broken to release pressure in time.

When A/a is more than or equal to 5HBW/mm and less than or equal to 10000HBW/mm, the weak area 131 is not broken in the normal service cycle of the single battery 10, and the weak area 131 can be broken in time to release pressure in the thermal runaway of the single battery 10.

Therefore, the ratio of the hardness of the weak area 131 to the thickness of the weak area 131 is set within a reasonable range, so that the weak area 131 has sufficient strength in the normal use process of the single battery 10, the pressure relief device 13 is not easy to break at the position of the weak area 131, the service life of the single battery 10 is prolonged, the pressure relief device 13 can timely relieve pressure through the weak area 131 when the single battery 10 is out of control due to heat, the risk of fire and explosion of the single battery 10 is reduced, and the safety of the single battery 10 is improved.

In some embodiments, 190HBW/mm ≦ A/a ≦ 4000HBW/mm.

Illustratively, A/a may be 190HBW/mm, 500HBW/mm, 1000HBW/mm, 4000HBW/mm, etc.

In the embodiment, the a/a is set to 190HBW/mm to 4000HBW/mm, so that the performance of the pressure relief device 13 is better, and the weak area 131 is guaranteed to have enough strength in the normal use process of the single battery 10 while the weak area 131 is guaranteed to be broken and relieved in time when the single battery 10 is out of control due to heat. On the premise of ensuring the safety of the battery cell 10, the service life of the battery cell 10 is prolonged.

In some embodiments, 8HBW ≦ A ≦ 200HBW.

A may be any value between 8HBW/mm and 200HBW/mm, for example, 8HBW, 10HBW, 15HBW, 19HBW, 50HBW, 100HBW, 200HBW, or the like.

In some embodiments, 0.02mm ≦ a ≦ 1.6mm.

a may be any value between 0.02mm and 1.6mm, such as 0.02mm, 0.025mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 1.6mm, and the like.

In some embodiments, with continued reference to fig. 4, the pressure relief device 13 includes a non-weakened area 132, the non-weakened area 132 is connected to the periphery of the weakened area 131, and the thickness of the non-weakened area 132 is b, which satisfies: a is less than b.

The non-weakened region 132 is more difficult to rupture than the weakened region 131, and when the internal pressure of the battery cell 10 in thermal runaway reaches the relief pressure, the weakened region 131 ruptures to relieve the pressure, while the non-weakened region 132 does not rupture. The thickness of the non-weakened areas 132 may or may not be uniform. If the thickness of the non-weak area 132 is uniform, the thickness measured at any position of the non-weak area 132 is the thickness of the non-weak area 132; if the thickness of the non-weakened area 132 is non-uniform, the thickness measured at the thinnest point of the non-weakened area 132 is the thickness of the weakened area 131, i.e., b is the minimum thickness of the non-weakened area 132.

The non-weakened area 132 and the weakened area 131 may be directly connected or indirectly connected.

In the present embodiment, by setting the thickness of the weak region 131 to be smaller than the thickness of the non-weak region 132, the weak region 131 is made to be more easily ruptured than the non-weak region 132, and the pressure relief device 13 is ensured to rupture and relieve pressure at the position of the weak region 131 when the battery cell 10 is thermally out of control.

In other embodiments, the weak region 131 may be easier to break than the non-weak region 132 by other methods, for example, the weak region 131 and the non-weak region 132 are equal in thickness, the material of the weak region 131 is different from that of the non-weak region 132, and the material of the weak region 131 is easier to break than that of the non-weak region 132, so that the weak region 131 breaks when the battery cell 10 is in thermal runaway, and the non-weak region 132 does not break.

In some embodiments, 0.05 ≦ a/b ≦ 0.95.

a/b may be any value between 0.05 and 0.95, such as 0.05, 0.12, 0.2, 0.8, 0.95, etc.

The ratio of the thickness of the weakened region 131 to the thickness of the non-weakened region 132 is too small, and the strength of the weakened region 131 may be insufficient. The ratio of the thickness of the weak region 131 to the thickness of the non-weak region 132 is too large, and the weak region 131 may not crack easily when the battery cell 10 is out of control due to thermal runaway, so that the pressure is not released in time, and accidents such as fire and explosion of the battery cell 10 may occur.

Therefore, setting the ratio of the thickness of the weak region 131 to the thickness of the non-weak region 132 to be 0.05 to 0.95 can reduce the probability of the weak region 131 breaking during the normal use of the single battery 10, and can also reduce the probability of accidents such as fire and explosion when the single battery 10 is out of control due to heat.

In some embodiments, 0.12 ≦ a/b ≦ 0.8.

In this embodiment, a/b is set to be 0.12-0.8, so that the performance of the pressure relief device 13 is better, and the weak area 131 is guaranteed to have enough strength in the normal use process of the single battery 10 while the weak area 131 is guaranteed to be broken and relieved in time when the single battery 10 is out of control due to heat.

In some embodiments, the non-weakened area 132 has a stiffness of B, satisfying: b is less than A.

The hardness of the non-weakened areas 132 is also brinell hardness. The hardness of the non-weakened area 132 can be measured at any surface in the thickness direction Z of the non-weakened area 132. Taking the end cap 12 of the battery cell 10 as the pressure relief device 13 for example, the hardness of the non-weakened area 132 may be measured on the outer surface of the non-weakened area 132, and the hardness of the non-weakened area 132 may also be measured on the inner surface of the non-weakened area 132. In the thickness direction Z of the non-weak area 132, the inner surface of the non-weak area 132 is a surface of the non-weak area 132 facing the inside of the battery cell 10, and the outer surface of the non-weak area 132 is a surface of the non-weak area 132 facing the outside of the battery cell 10.

In the present embodiment, the hardness of the weak region 131 is greater than that of the non-weak region 132, which is equivalent to increasing the hardness of the weak region 131, increasing the strength of the weak region 131, and reducing the risk of the weak region 131 cracking during normal use of the battery cell 10.

In some embodiments, A/B ≦ 3.

As B is less than A, understandably, A/B is more than 1 and less than or equal to 3. Illustratively, A/B may be 1.1, 1.5, 2, 2.5, 3, etc.

The greater the ratio of the hardness of the weak region 131 to the hardness of the non-weak region 132, the less the weak region 131 is broken, and if the ratio of the two is too large, the situation that the weak region 131 cannot be broken in time to release pressure when the battery cell 10 is in thermal runaway may occur.

Therefore, the ratio of the hardness of the weak area 131 to the hardness of the non-weak area 132 is set to be not more than 3, so that the weak area 131 can be broken and decompressed in time when the single battery 10 is out of control due to heat, and the safety of the single battery 10 is improved.

In some embodiments, with continued reference to fig. 4 and 5, the non-weakened areas 132 are directly connected to the weakened areas 131.

As shown in fig. 4, the pressure relief device 13 is a rectangular plate, the weak area 131 is a rectangle, and the non-weak area 132 is a portion of the pressure relief device 13 surrounding the peripheral edge of the weak area 131.

In this embodiment, the non-weakened area 132 is directly connected to the weakened area 131, and the structure is simple and easy to form.

In some embodiments, referring to fig. 6 and 7, fig. 6 is a top view of a pressure relief device 13 according to other embodiments of the present disclosure, and fig. 7 is a cross-sectional view B-B of the pressure relief device 13 shown in fig. 6. The pressure relief device 13 is provided with a recess 133, the pressure relief device 13 is provided with a connecting region 134 at the position where the recess 133 is provided, the non-weakened region 132 is connected to the periphery of the connecting region 134, and the connecting region 134 is partially formed with the weakened region 131.

The groove 133 may be of various shapes, such as rectangular, circular, oval, etc. The groove 133 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.

It will be appreciated that in this embodiment the non-weakened area 132 is indirectly connected to the weakened area 131 and that the connection area 134, in addition to the weakened area 131, connects the weakened area 131 to the non-weakened area 132. Taking the recess 133 and the weakened area 131 as an example, the non-weakened area 132 is a portion of the pressure relief device 13 that surrounds the peripheral edge of the connection area 134, and the portion of the connection area 134 that surrounds the peripheral edge of the weakened area 131 connects the weakened area 131 and the non-weakened area 132 together.

In the present embodiment, the connection region 134 is thinner than the non-weakened region 132, and it is easier to form the weakened region 131 in the connection region 134, so that the weakened region 131 is not too thick to meet the thickness requirement of the weakened region 131.

In some embodiments, the area of weakness 131 is integrally formed with the non-area of weakness 132.

It should be noted that the area of weakness 131 and the area of non-weakness 132 can be integrally formed, whether the area of weakness 131 is directly connected to the non-area of weakness 132 or indirectly connected thereto.

In this embodiment, the weak area 131 and the non-weak area 132 are integrally formed, so that the forming difficulty of the pressure relief device 13 is reduced, the economy is good, the integrity of the weak area 131 and the non-weak area 132 is good, and the strength of the weak area 131 can be improved.

In some embodiments, referring to fig. 8-11, fig. 8 is a top view of a pressure relief device 13 according to still other embodiments of the present disclosure; FIG. 9 is a cross-sectional C-C view of the pressure relief device 13 shown in FIG. 8; FIG. 10 is a top view of a pressure relief device 13 according to further embodiments of the present application; fig. 11 is a top view of a pressure relief device 13 according to another embodiment of the present disclosure. The pressure relief device 13 comprises a pressure relief portion 135, the weakened area 131 extending along an edge of the pressure relief portion 135, the pressure relief portion 135 being configured to open bordered by the weakened area 131.

The pressure relief portion 135 is the area of the pressure relief device 13 defined by the weakened region 131. The vent 135 defined by the area of weakness 131 can be one, for example, as shown in FIG. 8, the area of weakness 131 can be annular; as another example, as shown in FIG. 10, the weakened area 131 is C-shaped; the area of weakness 131 may define a plurality of vent portions 135, for example, as shown in figure 11, the area of weakness 131 is H-shaped and the area of weakness 131 defines two vent portions 135.

As shown in fig. 11, in an embodiment in which the region of weakness 131 is H-shaped, the region of weakness 131 may comprise a first section of weakness 1311, a second section of weakness 1312 and a third section of weakness 1313, the first section of weakness 1311 being located opposite the third section of weakness 1313, the second section of weakness 1312 being connected between the first section of weakness 1311 and the third section of weakness 1313, the first section of weakness 1311, the second section of weakness 1312 and the third section of weakness 1313 together forming an H-shape. In other embodiments, the region of weakness 131 may further comprise a fourth section of weakness located between the first and

third sections

1311, 1313 and arranged crosswise to the second section of weakness 1312, the location at which the fourth section of weakness intersects the second section of weakness 1312 forming the location at which the region of weakness 131 ruptures first.

The area of weakness 131 may be a closed structure extending along a closed path that is continuous end-to-end, e.g., as shown in fig. 8, the area of weakness 131 is annular; the area of weakness 131 may also be a non-closed structure extending along a non-closed path with a distance from the end to end, e.g. a C-shape as shown in fig. 10.

When the battery cell 10 thermally runaway, the weak region 131 is ruptured, and the pressure relief portion 135 can be opened with the weak region 131 as a boundary to relieve the pressure inside the battery cell 10. If the weakened area 131 is a closed structure, the weakened area 131 may be opened in a breakaway manner; if the area of weakness 131 is a non-enclosed structure, the area of weakness 131 may be opened in an outwardly turned manner.

Illustratively, as shown in fig. 8 and 9, the weakened area 131 is directly connected to the non-weakened area 132, the non-weakened area 132 is connected to an outer edge of the weakened area 131, and the vent 135 is connected to an inner edge of the weakened area 131.

Illustratively, as shown in fig. 10 and 11, a groove 133 is provided on the pressure relief device 13, the pressure relief device 13 forms a connecting region 134 at the position where the groove 133 is provided, the non-weakened region 132 is connected to the periphery of the connecting region 134, and the connecting region 134 partially forms the weakened region 131, so that the weakened region 131 is indirectly connected with the non-weakened region 132.

In this embodiment, the pressure relief portion 135 increases the pressure relief area of the pressure relief device 13, thereby improving the pressure relief efficiency.

In some embodiments, with continued reference to fig. 4-11, the pressure relief device 13 is provided with a pressure relief groove 136, and the pressure relief device 13 forms a weakened area 131 at the position where the pressure relief groove 136 is provided.

After the pressure relief groove 136 is formed in the pressure relief device 13, the remaining portion of the pressure relief device 13 at the position of the pressure relief groove 136 is the weak area 131. The thickness of the non-weakened area 132 of the pressure relief device 13 is larger than the thickness of the weakened area 131 by providing a pressure relief groove 136 in the pressure relief device 13. As shown in fig. 4, 5, 8 and 9, in the case where the recess 133 is not provided in the pressure relief device 13 but the pressure relief groove 136 is provided, the weak area 131 may be integrally formed with the non-weak area 132. As shown in fig. 6, 7, 10, and 11, in the case where both the groove 133 and the pressure relief groove 136 are provided in the pressure relief device 13, the pressure relief groove 136 may be provided on the groove bottom surface of the groove 133 (the surface of the connection region 134). During molding, a groove 133 may be formed on the pressure relief device 13, and then a pressure relief groove 136 may be formed on the groove bottom surface of the groove 133, so as to integrally mold the weak area 131 and the non-weak area 132.

The relief groove 136 may be a variety of shapes, such as rectangular, circular, oval, annular, U-shaped, C-shaped, H-shaped, and the like. The shape of the pressure relief groove 136 is the same as the shape of the weak area 131, for example, if the pressure relief groove 136 is rectangular, the weak area 131 is also rectangular; for another example, if the pressure relief groove 136 is C-shaped, the weakened area 131 is also C-shaped; if the relief groove 136 is H-shaped, the weakened region 131 is also H-shaped. The pressure relief groove 136 may be formed in various manners, such as punch forming, milling forming, and the like, which are not limited in this embodiment. After forming the pressure relief groove 136 by means of stamping, it is achieved that the stiffness of the weakened area 131 is greater than the stiffness of the non-weakened area 132.

As shown in fig. 5, 7 and 9, the pressure relief device 13 has a first surface 137 and a second surface 138 oppositely disposed in the thickness direction Z of the non-weakened area 132, the distance between the first surface 137 and the second surface 138 being the thickness of the non-weakened area 132. As shown in fig. 5 and 9, in the embodiment where the pressure relief device 13 is provided with the pressure relief groove 136 but the groove 133 is not provided, the pressure relief groove 136 may be provided on one of the first surface 137 and the second surface 138, or the pressure relief groove 136 may be provided on both the first surface 137 and the second surface 138. As shown in fig. 7, in the embodiment where the pressure relief device 13 is provided with both the pressure relief groove 136 and the groove 133, the groove 133 may be provided on one of the first surface 137 and the second surface 138, and the pressure relief groove 136 is provided on the groove bottom surface of the groove 133, or the grooves 133 may be provided on both the first surface 137 and the second surface 138, and the pressure relief groove 136 is provided on the groove bottom surface of the groove 133. Taking the pressure relief device 13 as the end cap 12 of the battery cell 10 as an example, the first surface 137 may be the surface of the end cap 12 facing the inside of the battery cell 10, and the second surface 138 may be the surface of the end cap 12 facing the outside of the battery cell 10.

In this embodiment, the weakened region 131 is formed by providing the pressure relief device 13 with the pressure relief groove 136, and the weakened region 131 is formed in a simple manner.

In some embodiments, referring to fig. 12 to 14, fig. 12 is a partial enlarged view of the pressure relief device 13 shown in fig. 5 at D; FIG. 13 is an enlarged view of a portion of the pressure relief device 13 shown in FIG. 7 at E; fig. 14 is a partial enlarged view of the pressure relief device 13 shown in fig. 9 at F. The surface layer of the pressure relief device 13 is formed with an oxidation resistant layer 139, and the oxidation resistant layer 139 is arranged along the groove wall surface of the pressure relief groove 136 in the region where the pressure relief groove 136 is provided.

The portion of the oxidation resistant layer 139 located in the weakened area 131 defines the relief groove 136. The pressure relief groove 136 groove wall surfaces include a groove side surface and a groove bottom surface, both of which are portions of the outer surface of the oxidation resistant layer 139. The oxidation resistant layer 139 may be a metal plating on the surface of the pressure relief device 13. For example, the main body of the pressure relief device 13 is a steel layer, and the oxidation resistant layer 139 is a nickel layer plated on the surface of the main body. In measuring the hardness of the weak area 131, the hardness of the portion of the main body portion located in the weak area 131 is measured. In measuring the hardness of the non-weakened area 132, the hardness of the portion of the main body portion located in the non-weakened area 132 is measured.

The oxidation resistant layer 139 protects the pressure relief device 13, reducing the risk of oxidation of the pressure relief device 13. Because the oxidation-resistant layer 139 is disposed along the groove wall surface of the pressure-relief groove 136 in the area where the pressure-relief groove 136 is disposed, the oxidation-resistant layer 139 can protect the area where the pressure-relief groove 136 is disposed of the pressure-relief device 13 well, and the risk that the strength of the weak area 131 is weakened due to oxidation of the pressure-relief device 13 in the area where the pressure-relief groove 136 is disposed is reduced.

In some embodiments, with continued reference to fig. 12-14, the pressure relief device 13 includes a non-weakened area 132, the non-weakened area 132 is connected to the periphery of the weakened area 131, the thickness of the oxidation resistant layer 139 in the weakened area 131 is d, and the thickness of the oxidation resistant layer 139 in the non-weakened area 132 is e, which satisfy: d is less than e.

In the embodiment, d is less than e, so that the influence of the oxidation resistant layer 139 on the weak region 131 is reduced, and the weak region 131 can be broken to release pressure in time when the battery cell 10 is out of control due to heat.

In some embodiments, referring to fig. 15 and 16, fig. 15 is an isometric view of a pressure relief device 13 provided in some embodiments of the present application; fig. 16 is a cross-sectional view of the pressure relief device 13 shown in fig. 15. The pressure relief device 13 includes a plurality of walls that collectively enclose a receiving space 140 for receiving the electrode assembly 2 of the battery cell 10, at least one wall being formed with the weak region 131.

The pressure relief device 13 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc. Illustratively, in fig. 15 and 16, the pressure relief device 13 is a rectangular parallelepiped. In the pressure relief device 13, the weakened area 131 may be formed in one wall, or the weakened area 131 may be formed in a plurality of walls. For a wall formed with a weakened area 131, if the weakened area 131 is directly connected with a non-weakened area 132, the other areas of the wall except the weakened area 131 are the non-weakened areas 132.

Taking the pressure relief device 13 as a rectangular parallelepiped for example, the number of the walls in the pressure relief device 13 may be six, five of the walls constitute the case 11 of the casing 1, the other wall serves as the cap 12 of the casing 1, and the case 11 and the cap 12 together constitute the pressure relief device 13. The pressure relief device 13 may also have five walls, five walls forming the casing 11 of the housing 1, the casing 11 acting as the pressure relief device 13.

The pressure relief device 13 can provide the accommodation space 140 for the electrode assembly 2, so that the pressure relief device 13 has both an accommodation function of accommodating the battery cell 10 and a pressure relief function.

In some embodiments, with continued reference to fig. 15 and 16, the plurality of walls includes a bottom wall 141 and a plurality of side walls 142, the plurality of side walls 142 are disposed around the bottom wall 141, the plurality of side walls 142 and the bottom wall 141 together define a receiving space 140, and the pressure relief device 13 is opened at an end opposite to the bottom wall 141. The bottom wall 141 is formed with a weakened area 131; and/or at least one of the sidewalls 142 is formed with a weakened area 131.

The side walls 142 in the pressure relief device 13 may be three, four, five or more. Illustratively, pressure relief device 13 is a rectangular parallelepiped, and there are five walls in pressure relief device 13, one wall being bottom wall 141 and four walls being side walls 142. In fig. 16, the bottom wall 141 is formed with a weakened area 131.

In this embodiment, the bottom wall 141 may be formed with a weakened area 131 to allow pressure relief from the bottom wall 141. At least one of the sidewalls 142 may also be formed with a weakened area 131 to allow pressure relief from the sidewall 142. If the plurality of side walls 142 are formed with the weak regions 131 so that the pressure relief device 13 can perform pressure relief from a plurality of directions, even if the weak region 131 of one side wall 142 is blocked, the pressure relief device can perform pressure relief through the weak regions 131 of the other side walls 142. Of course, the weakened area 131 may be formed on both the bottom wall 141 and at least one of the side walls 142 to improve the pressure relief efficiency of the pressure relief device 13.

In some embodiments, referring to fig. 17, fig. 17 is an isometric view of a pressure relief device 13 provided in accordance with further embodiments of the present application. The pressure relief device 13 is of a plate-like structure.

A pressure relief device 13 in the form of a plate may be provided as an end cap 12 of the housing 1 to close the opening of the casing 11. The pressure relief device 13 may also be a plate-like member, such as a rupture disk, mounted to the end cap 12 and/or the housing 11. The pressure relief device 13 may be of various shapes, such as circular, rectangular, etc. Illustratively, in fig. 17, the pressure relief device 13 is a rectangular plate-like structure.

In the present embodiment, the pressure relief device 13 has a plate-like structure, and the pressure relief device 13 is simple in structure and easy to mold and manufacture.

Referring to fig. 18 and 19, fig. 18 is a schematic structural view of a housing 1 according to some embodiments of the present disclosure; fig. 19 is a schematic structural diagram of a housing 1 according to another embodiment of the present application. The embodiment of the present application provides a housing 1, and the housing 1 includes the pressure relief device 13 provided in any one of the above embodiments.

In some embodiments, as shown in fig. 18, the pressure relief device 13 is a housing 11 of the enclosure 1. In other embodiments, as shown in fig. 19, the pressure relief device 13 is an end cap 12 of the housing 1.

The embodiment of the application provides a battery unit 10, which comprises an electrode assembly 2 and a shell 1 provided by any one of the above embodiments, wherein the electrode assembly 2 is accommodated in the shell 1.

The embodiment of the present application provides a battery 100, which includes a box 20 and the single battery 10 provided in any one of the above embodiments, and the single battery 10 is accommodated in the box 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, as shown in fig. 19, the present embodiment further provides a square casing 1, which includes a casing 11 and an end cap 12, wherein the end cap 12 closes an opening of the casing 11, the end cap 12 includes a weak area 131 and a non-weak area 132 directly connected to the weak area 131, the non-weak area 132 is connected to the periphery of the weak area 131, the thickness of the weak area 131 is a, the hardness of the weak area 131 is a, the thickness of the non-weak area 132 is B, and the hardness of the non-weak area 132 is B, which satisfies: a is more than B, B is more than A, and A/a is more than or equal to 5HBW/mm and less than or equal to 10000HBW/mm. The ratio of the hardness of the weak area 131 to the thickness of the weak area 131 is set within a reasonable range, so that the weak area 131 has sufficient strength in the normal use process of the single battery 10, the pressure relief device 13 is not easy to break at the position of the weak area 131, the service life of the single battery 10 is prolonged, the pressure relief device 13 can timely relieve pressure through the weak area 131 when the single battery 10 is out of control due to heat, the risk of fire and explosion of the single battery 10 is reduced, and the safety of the single battery 10 is improved.

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 only used to illustrate the technical solutions of the present application, and are not used to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. 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 is used for a battery monomer, and is characterized in that a weak area is formed in the local part of the pressure relief device and is used for breaking when the battery monomer releases pressure;

wherein the thickness of the weak area is a, the hardness of the weak area is A, and the following conditions are met: a/a is more than or equal to 5HBW/mm and less than or equal to 10000HBW/mm.

2. The pressure relief device according to claim 1, wherein 190HBW/mm ≤ a/a ≤ 4000HBW/mm.

3. The pressure relief device according to claim 1, wherein A is 8HBW ≦ 200HBW.

4. The pressure relief device according to claim 1, wherein a is 0.02mm ≤ 1.6mm.

5. The pressure relief device according to claim 1, wherein said pressure relief device comprises a non-weakened area connected around said weakened area, said non-weakened area having a thickness b satisfying: a is less than b.

6. The pressure relief device according to claim 5, wherein a/b is 0.05-0.95.

7. The pressure relief device according to claim 6, wherein 0.12. Ltoreq. A/b. Ltoreq.0.8.

8. The pressure relief device according to claim 5, wherein said non-weakened area has a hardness of B, satisfying: b is less than A.

9. The pressure relief device of claim 8, wherein A/B is ≦ 3.

10. The pressure relief device according to claim 5, wherein said non-weakened area is directly connected to said weakened area.

11. The pressure relief device according to claim 5, wherein said pressure relief device is provided with a recess, said pressure relief device forming a connection area at the location where said recess is provided, said non-weakened area being connected to the periphery of said connection area, said connection area locally forming said weakened area.

12. The pressure relief device according to claim 5, wherein said area of weakness is integrally formed with said non-area of weakness.

13. The pressure relief device according to any of claims 1-12, comprising a pressure relief portion, said area of weakness extending along an edge of said pressure relief portion, said pressure relief portion being configured to open bordered by said area of weakness.

14. The pressure relief device according to any of claims 1-12, wherein said pressure relief device is provided with a pressure relief groove, said pressure relief device forming said area of weakness at the location where said pressure relief groove is provided.

15. The pressure relief device according to claim 14, wherein an oxidation resistant layer is formed on a surface layer of the pressure relief device, and the oxidation resistant layer is disposed along a groove wall surface of the pressure relief groove in an area where the pressure relief groove is disposed.

16. The pressure relief device according to claim 15, wherein said pressure relief device comprises a non-weakened area connected around said weakened area, said oxidation resistant layer having a thickness d in said weakened area and e in said non-weakened area, such that: d is less than e.

17. The pressure relief device according to any of claims 1-12, wherein said pressure relief device comprises a plurality of walls, said walls collectively enclosing a receiving space for receiving an electrode assembly of said battery cell, at least one of said walls being formed with said weakened zone.

18. The pressure relief device according to claim 17, wherein said plurality of walls comprises a bottom wall and a plurality of side walls, said plurality of side walls being enclosed around said bottom wall, said plurality of side walls and said bottom wall together enclosing said containment volume, said pressure relief device defining an opening at an end opposite said bottom wall;

the bottom wall is formed with the weakened area; and/or at least one of said side walls is formed with said area of weakness.

19. The pressure relief device according to any of claims 1-12, wherein said pressure relief device is a plate like structure.

20. A housing comprising a pressure relief device according to any of claims 1-19.

21. A battery cell, comprising:

the housing of claim 20;

an electrode assembly housed within the case.

22. A battery, comprising:

a box body;

the battery cell of claim 21, the battery cell being housed within the case.

23. An electrical device comprising the battery of claim 22.