Battery monomer, battery device and electric equipment

Abstract

The utility model relates to the technical field of batteries, and discloses a battery monomer, a battery device and electric equipment, the battery monomer comprises a flexible shell and an electrode assembly, and the electrode assembly is arranged in the flexible shell; wherein the flexible shell is provided with a side face opposite to the large face of the electrode assembly and a circumferential face avoiding the large face, and the circumferential face and the side face are connected in the circumferential direction around the electrode assembly; and at least the circumferential surface is provided with a pressure relief area. According to the battery monomer disclosed by the embodiment of the invention, the pressure relief area is arranged on the flexible shell, so that directional pressure relief of the battery monomer is realized during thermal runaway, and ordered discharge of high-temperature gas fire flow in the battery monomer can be realized, so that damage to an insulation interface of a battery device is reduced, secondary damage is reduced, and the battery device is more stable in performance. And the reliability of the battery monomer and even the battery device is improved.

Description

Technical Field

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

[0002] In the related art, there is a problem of high difficulty in directional pressure relief of soft-pack battery cells, which affects the further improvement of the reliability of the soft-pack battery device. Utility Model Content

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present application is to provide a battery cell, a battery device and an electrical device, wherein the battery cell has higher reliability.

[0004] In a first aspect, the present application provides a battery cell, comprising: a flexible shell and an electrode assembly, wherein the electrode assembly is arranged in the flexible shell; wherein the flexible shell has a side surface opposite to the large surface of the electrode assembly, and a circumferential surface avoiding the large surface, the circumferential surface and the side surface are circumferentially connected around the electrode assembly; at least the circumferential surface is provided with a pressure relief zone.

[0005] According to the battery cell of the embodiment of the present application, a pressure relief zone is provided on the flexible casing to achieve directional pressure relief of the battery cell in the event of thermal runaway, and orderly discharge of high-temperature gas and fire flow inside the battery cell can be achieved, so as to reduce damage to the insulating interface of the battery device, reduce secondary damage, and improve the reliability of the battery cell and even the battery device.

[0006] According to some embodiments of the present application, the pressure relief zone includes a weak portion disposed on a circumferential surface, and the weak portion is configured to rupture to relieve pressure when the pressure in the flexible shell exceeds a pressure threshold.

[0007] In the above technical solution, through the setting of the weak part, the pressure relief area formed on the circumferential surface can release pressure in time when thermal runaway occurs in the battery cell, thereby improving reliability. At the same time, the pressure relief part is located on the circumferential surface, and the position of the pressure relief part is more reasonable, which can realize directional pressure relief along the circumferential surface. The pressure relief direction is reasonable, which can reduce the impact on surrounding components, especially adjacent battery cells, during the pressure relief process, and further improve the reliability of the battery cell.

[0008] According to some embodiments of the present application, the film material of the flexible housing is a stacked multi-layer film structure and includes at least a metal barrier layer, and the weak portion is formed in the metal barrier layer, or the weak portion extends and penetrates at least a portion of the metal barrier layer.

[0009] In the above technical solution, the film material of the flexible shell refers to the material of the flexible shell itself, and the film material itself is constructed as a multi-layer film structure, so as to improve the structural strength of the flexible shell through the metal barrier layer in the multi-layer film structure, reduce the probability of the electrode assembly piercing the flexible shell, and improve the reliability of the battery cell. The weak part is formed on the metal barrier layer, or penetrates the metal barrier layer, which can reduce the processing difficulty of the weak part and make the stability and reliability of the weak part higher.

[0010] According to some embodiments of the present application, the weak portion is configured as a notch, and the notch penetrates at least a portion of the metal barrier layer.

[0011] In the above technical solution, in the embodiment where the weak portion is constructed as a notch, the notch only penetrates at least a portion of the metal barrier layer, and the notch extends from a side surface of the flexible shell away from the electrode assembly toward a side surface of the flexible shell adjacent to the electrode assembly, thereby achieving structural weakening of a partial area to form a weak portion. At the same time, the insulation effect between the metal barrier layer and the interior of the flexible shell can remain stable, and the reliability and stability of the battery cell can be improved.

[0012] According to some embodiments of the present application, the contour shape of the notch is one or more of a circle, an ellipse, a rectangle, a straight line, and a Z shape.

[0013] In the above technical solution, by setting a notch of a suitable shape as a weak part, not only can the processing difficulty be reduced to reduce the production cost of the battery cell, but the notch can be set at a suitable position on a suitable surface to achieve directional pressure relief, which can also further improve the reliability of the battery cell.

[0014] According to some embodiments of the present application, there are a plurality of notches, which are arranged at intervals on the circumferential surface or side surface of the flexible shell.

[0015] In the above technical solution, by arranging a plurality of notches at intervals on the circumferential surface or the side surface, rapid pressure relief can be achieved under the premise of achieving directional pressure relief (i.e., the direction of the surface where the notches are located) to reduce the impact during the pressure relief process, and the force distribution on the surface where the multiple notches are located is more uniform, and the pressure relief response speed and reliability can also be higher.

[0016] According to some embodiments of the present application, the thickness of the film material of the flexible housing is D1, the notch depth is D2, and 1 / 3≤D1 / D2≤2 / 3 is satisfied.

[0017] In the above technical solution, the notch depth is not less than one third of the thickness of the film material, which can avoid the notch depth being too shallow, so that the weak part has a better preferential rupture effect compared with other areas of the flexible shell, and the reliability and stability of the pressure relief zone are better. At the same time, the notch depth is not greater than two thirds of the thickness of the film material, which can avoid the notch being too deep, so as to take into account the structural strength of the flexible shell and reduce the probability of false triggering of the weak part.

[0018] According to some embodiments of the present application, the film material of the flexible shell includes: a metal barrier layer, a first plastic barrier layer located on the side of the metal barrier layer facing the electrode assembly, and a second plastic barrier layer on the side away from the electrode assembly. The metal barrier layer includes a main body area and a weak area corresponding to the weak part, and the weak area and the main body area are made of different materials.

[0019] In the above technical solution, the weak portion of the present application is defined by the weak area of ​​the metal barrier layer, and the weak area and the main body area are made of different materials to achieve differentiated settings of the structural strength between the weak portion and the main body area. While achieving the above technical effects, the outer surface of the flexible shell can be smoother, which can improve the surface flatness of the battery cell and reduce the probability of scratches between surrounding components.

[0020] According to some embodiments of the present application, the film material of the flexible shell includes: a metal barrier layer, a first plastic barrier layer located on the side of the metal barrier layer facing the electrode assembly, and a second plastic barrier layer on the side away from the electrode assembly, the metal barrier layer includes a main body area and a weak area corresponding to the weak part, and the thickness of the weak area is less than the thickness of the main body area.

[0021] In the above technical scheme, the weak portion of the present application is defined by a weak area of ​​the metal barrier layer, and the weak area has a different thickness from the main area, so as to achieve a differentiated setting of the structural strength between the weak portion and the main area. While achieving the above technical effects, it can also reduce the processing difficulty of the thinned portion and reduce material costs.

[0022] According to some embodiments of the present application, the film material also includes: a filling layer, the filling layer is located between the first plasticized barrier layer and the metal barrier layer and fills the weak area, and / or the filling layer is located between the second plasticized barrier layer and the metal barrier layer and is used to fill the weak area.

[0023] In the above technical solution, by setting the filling layer, the flatness of the surface of the flexible shell facing the electrode assembly and some surfaces away from the electrode assembly can be improved, the probability of scratches between the flexible shell and surrounding components (such as scratches on the electrode assembly) can be reduced, and the reliability of the flexible shell can be improved.

[0024] According to some embodiments of the present application, the battery cell is any one of a lithium iron phosphate battery cell, a ternary lithium battery cell and a solid-state battery cell.

[0025] In the above technical scheme, in the embodiment where the present application is constructed as a lithium iron phosphate battery cell, the reliability of the battery cell can be improved and the cycle life of the battery cell can be extended. In the embodiment where the present application is constructed as a ternary lithium battery cell, the energy density of the battery cell can be improved and the cruising range can be improved. In the embodiment where the present application is constructed as a solid-state battery cell, not only the energy density can be improved, but also the reliability can be improved.

[0026] According to some embodiments of the present application, the battery cell is a lithium iron phosphate battery cell, and the positive electrode material of the battery cell has a usage ratio of positive electrode active material, positive electrode binder and positive electrode conductive agent of 96: (1-3): (1-3); the battery cell is a ternary lithium battery cell, and the positive electrode material of the battery cell has a usage ratio of positive electrode active material, positive electrode binder and positive electrode conductive agent of 96: (2-3): (1-2).

[0027] In the above technical scheme, in an embodiment where the battery cell structure is a lithium iron phosphate battery cell, the positive electrode active material, the positive electrode binder and the positive electrode conductive agent adopt the above ratio, which can improve the electrochemical performance and mechanical stability of the battery cell, and in an embodiment where the battery cell structure is a ternary lithium battery cell, the positive electrode active material, the positive electrode binder and the positive electrode conductive agent adopt the above ratio, which can improve the energy density and cycle life of the battery.

[0028] In a second aspect, the present application provides a battery device, including: a box body and a battery pack, there is at least one battery pack, the battery pack includes: at least one battery cell in the above embodiment and a covering shell, at least one side surface of the covering shell has a pressure relief portion.

[0029] According to the battery device of the embodiment of the present application, a pressure relief portion cooperating with the pressure relief area is provided on the covering shell. When thermal runaway occurs in the battery cell, the high-temperature gas and fire flow discharged through the pressure relief area (weak portion) can be further released outward through the pressure relief portion. Through the cooperation between the weak portion and the pressure relief portion, the high-temperature gas and fire flow can be directional discharged, thereby improving the reliability of the battery device.

[0030] According to some embodiments of the present application, the covering shell includes a first plate and second plates located on both sides of the first plate, a pressure relief portion is formed on the first plate, and the pressure relief area is at least partially opposite to the pressure relief portion.

[0031] In the above technical scheme, on the one hand, the gas and fire flow generated after the thermal runaway of the battery cell can be discharged in a direction and orderly to reduce damage, especially secondary damage. On the other hand, the connection path between the pressure relief zone and the pressure relief part is shorter, which can achieve rapid discharge. At the same time, the gas and fire flow stays in the coating shell for a shorter time, which has less impact on other battery cells around the thermal runaway battery cell, and can further reduce the spread speed of thermal runaway, thereby improving the reliability of the battery pack and the battery device.

[0032] According to some embodiments of the present application, the second plate is opposite to the side surface, and a projected contour area of ​​the second plate toward the side surface of the flexible housing is smaller than or equal to an area of ​​the side surface.

[0033] In the above technical solution, on the one hand, it can avoid the second plate being too large, resulting in the second surface being unable to connect to the box body, and can improve the fixation stability and reliability of the battery pack in the box body. On the other hand, the material used for the second plate can be less, and the material cost of the battery pack and the battery device can also be reduced.

[0034] According to some embodiments of the present application, the first plate is spaced apart from a side of the circumferential surface having the weak portion to define an exhaust passage.

[0035] In the above technical solution, the high-temperature gas and fire flow generated after the weak part ruptures can be first released to the exhaust channel, and after preliminary buffering through the exhaust channel, it can be discharged through the pressure relief part. The pressure of the high-temperature gas and fire flow after flowing out of the pressure relief part can be reduced, so as to reduce the impact and damage after thermal runaway of the battery cell.

[0036] According to some embodiments of the present application, the first plate is configured as a straight plate or a curved plate.

[0037] According to some embodiments of the present application, there are multiple pressure relief parts, and the multiple pressure relief parts are arranged at intervals in the length direction and / or width direction of the first plate.

[0038] In the above technical solution, the multiple weak parts on each battery cell can have a corresponding pressure relief part, so that the high-temperature gas and fire flow buffered by the exhaust channel can be discharged directly through the corresponding pressure relief part, thereby increasing the discharge speed and reducing the residence time of the high-temperature gas and fire flow in the exhaust channel during the discharge process, so as to reduce the spread speed of thermal runaway between adjacent battery cells in the battery pack and improve the reliability of the battery pack.

[0039] According to some embodiments of the present application, the covering shell is constructed as an aluminum shell or a stainless steel shell.

[0040] In the above technical scheme, in some embodiments, the covering shell is constructed as an aluminum shell, and in other embodiments, the covering shell is constructed as a stainless steel shell, so that the temperature resistance and structural strength of the covering shell are much higher than those of the flexible shell. By using the covering shell with a certain structural strength and rigidity to support and protect the battery cell outside the battery cell, the structural strength of the battery pack can be improved, the propagation speed of thermal runaway between adjacent battery packs can be reduced, and the reliability of the battery device can be improved.

[0041] According to some embodiments of the present application, the box body has a bottom plate, and the bottom plate is connected to the battery cell through an adhesive layer.

[0042] In the above technical solution, the bottom plate of the box body is connected to the second surface of the battery cell through the adhesive layer to achieve the fixation of the battery pack on the box body, thereby improving the fixation stability and reliability of the battery pack.

[0043] According to some embodiments of the present application, the bottom plate includes a cold plate, and the glue layer is located between the cold plate and the plurality of battery cells.

[0044] In the above technical solution, the adhesive layer is constructed as structural adhesive, and the bottom plate is constructed as a cold plate, or the bottom plate provided with a cold plate is connected to the battery cell. On the premise of achieving stable and reliable fixation of the battery pack in the box, the temperature of the battery pack can also be regulated by the cold plate, so that the battery pack can operate at a suitable temperature, which can improve the working stability and reliability of the battery pack, reduce the probability of overheating of the battery pack, and reduce the probability of thermal runaway of the battery pack, thereby improving the reliability of the battery pack and even the battery device.

[0045] According to some embodiments of the present application, the glue layer includes: a glue layer body and a glue overflow portion, the glue overflow portion is located on a side of the glue layer body facing the multiple battery cells and is located between adjacent battery cells and / or between a battery cell and the second plate.

[0046] In the above technical solution, when the structural adhesive is used to connect and fix the battery cell to the cold plate, at least part of the adhesive layer overflows between adjacent battery cells and / or between the second plate and the battery cell, and forms an overflowing adhesive portion. By setting the overflowing adhesive portion, not only the area between the adhesive layer and the battery cell, and between the adhesive layer and the second plate can be increased to improve the fixation stability and reliability of the battery pack on the box, but also the gaps between adjacent battery cells and between the battery cell and the second plate can be filled by the overflowing adhesive portion to achieve the limitation of the battery cell and the covering shell, reduce the movement of the battery pack in the box, and reduce the movement of the battery cell in the covering shell.

[0047] In a third aspect, the present application proposes an electrical device, including: the battery device in the above embodiment.

[0048] According to some embodiments of the present application, the electrical device is a vehicle.

[0049] In the above technical solution, the electrical equipment is constructed as a vehicle, and the battery device has a higher energy density and higher reliability, which can improve the vehicle's driving safety while increasing the vehicle's cruising range.

[0050] According to some embodiments of the present application, the battery device is integrated into the chassis of the vehicle, and the top plate of the box body participates in defining the vehicle body floor.

[0051] In the above technical solution, the electrical equipment can be a vehicle, and the battery device can be integrated on the chassis of the vehicle, that is, the body structure is a split body, the upper body and the integrated intelligent chassis are assembled, and the battery device forms a part of the integrated intelligent chassis, so that the top plate of the box can also participate in defining the body floor, which can save meaningless multi-layer plate stacking, reduce material costs, and make the space occupancy of the chassis more reasonable. The space inside the chassis for accommodating the battery device is larger and the energy density is higher.

[0052] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0054] Figure 1 is a schematic diagram of a battery device according to an embodiment of the present application;

[0055] Figure 2 is a schematic diagram of an electrical device according to an embodiment of the present application;

[0056] Figure 3 is a schematic diagram of a battery cell according to an embodiment of the present application (first notch);

[0057] Figure 4 yes Figure 3 A schematic top view of a battery cell;

[0058] Figure 5 is a schematic diagram of a battery cell according to an embodiment of the present application (second notch);

[0059] Figure 6 yes Figure 5 A schematic top view of a battery cell;

[0060] Figure 7 is a schematic diagram of a battery cell according to an embodiment of the present application (third notch);

[0061] Figure 8 yes Figure 7 A schematic top view of a battery cell;

[0062] Fig. 9 is a schematic diagram of a film material of a flexible shell of a battery cell according to an embodiment of the present application (the notch extends to the metal barrier layer);

[0063] Fig.10 is a schematic diagram of a film material of a flexible shell of a battery cell according to an embodiment of the present application (the material of the main body area and the weak area is different);

[0064] Fig.11 is a schematic diagram of a film material of a flexible shell of a battery cell according to an embodiment of the present application (the thickness of the main body area and the weak area are different);

[0065] Fig.12 is a schematic diagram of the extension position of the notch according to an embodiment of the present application;

[0066] Fig.13 is a schematic diagram of a battery pack according to an embodiment of the present application;

[0067] Fig.14 It is a schematic diagram of the coordination between the battery pack and the base plate according to an embodiment of the present application.

[0068] Reference numerals:

[0069] Battery cell 100,

[0070] Flexible shell 10, side surface 11, circumferential surface 12, pressure relief area 121, weak portion 122,

[0071] The electrode assembly 20,

[0072] Metal barrier layer a, body area a1, weak area a2, first plastic barrier layer b, second plastic barrier layer c, first adhesive layer d, second adhesive layer e, filling layer f,

[0073] Battery device 200, power-consuming equipment 300,

[0074] Box body 400, bottom plate 410, glue layer 420, glue layer body 421, glue overflow part 422,

[0075] Battery pack 500, covering shell 510, first plate 511, second plate 512, pressure relief portion 520, exhaust channel 530,

[0076] Controller 600 , motor 700 . DETAILED DESCRIPTION

[0077] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0078] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0079] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0080] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0081] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0082] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0083] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0084] In the description of the present application, a first feature being “on” or “under” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact with each other but are in contact with each other via another feature therebetween.

[0085] In the description of the present application, “above”, “over” and “above” a first feature to a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0086] The term "multiple" used in this application refers to more than two (including two). The battery cell may be a secondary battery, which refers to a battery cell that can be continuously used by activating the active material by charging after the battery cell is discharged.

[0087] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present application.

[0088] The battery device mentioned in the embodiments of the present application may include one or more battery packs for providing voltage and capacity. The battery pack may include a plurality of battery cells, which are connected in series, in parallel or in hybrid connection through a busbar.

[0089] In some embodiments, a battery pack is generally formed by arranging a plurality of battery cells.

[0090] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery packs, wherein the battery packs are accommodated in the case.

[0091] As an example, the battery pack may be a battery module, and the battery pack may be accommodated in the box by fixing the battery module in the box.

[0092] As an example, the box may include a first box and a second box. The first box and the second box are buckled together to form a closed space inside the box to accommodate the battery pack. The closed space here means covered or closed, which may be sealed or unsealed. The first box may be a top cover or a bottom plate.

[0093] As an example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery pack.

[0094] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0095] The technical solutions described in the embodiments of the present application are applicable to battery devices and electrical equipment using the battery devices.

[0096] Electrical equipment may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, electric tools, and the like. Vehicles may be fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or extended-range vehicles, and the like; spacecraft include airplanes, rockets, space shuttles, and spacecraft, and the like; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0097] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0098] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of an electric device 300 provided in some embodiments of the present application. A battery device 200 is provided inside a vehicle, and the battery device 200 can be provided at the bottom, head, or tail of the vehicle. The battery device 200 can be used to power the vehicle, for example, the battery device 200 can be used as an operating power source for the vehicle.

[0099] The vehicle may further include a controller 600 and a motor 700 . The controller 600 is used to control the battery device 200 to supply power to the motor 700 . The motor 700 serves as a load, for example, to meet the power requirements of starting, navigating and driving the vehicle.

[0100] In some embodiments of the present application, the battery device 200 can not only be used as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0101] Please refer to Figure 2 , Figure 2 The exploded view of the battery device 200 provided in some embodiments of the present application. The battery device 200 includes a box body 400 , and the box body 400 is used to accommodate the battery cell 100 .

[0102] Among them, the box body 400 is a component for accommodating the battery cell 100, and the box body 400 provides a placement space for the battery pack 500. The box body 400 can adopt a variety of structures. In some embodiments, the box body 400 may include a tray and a cover plate, and the tray and the cover plate cover each other to define a placement space for accommodating the battery cell 100. The tray and the cover plate can be in a variety of shapes, such as a rectangular parallelepiped, a cylinder, etc. The tray can be a hollow structure with one side open, and the cover plate can also be a hollow structure with one side open, and the open side of the cover plate covers the open side of the tray, thereby forming a box body 400 with a placement space. It is also possible that the tray is a hollow structure with one side open, and the cover plate is a plate-like structure, and the cover plate covers the open side of the tray, thereby forming a box body 400 with a placement space.

[0103] As an example, the battery cell 100 may be a pouch battery cell.

[0104] In the battery device 200, there can be one or more battery cells 100. Multiple battery cells 100 are loaded into a battery pack 500 through a covering shell 510, and one or more battery packs 500 are loaded in the box 400. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells 100 are both connected in series and in parallel. Multiple battery cells 100 can be connected in series, in parallel, or in mixed connection to form a battery pack 500, and multiple battery packs 500 are then connected in series, in parallel, or in mixed connection to form a whole and accommodated in the box 400.

[0105] The battery cell 100 is a minimum energy unit of the battery device 200 . The battery cell 100 includes a flexible housing 10 and an electrode assembly 20 disposed in the flexible housing 10 .

[0106] The internal environment formed by the flexible housing 10 can be used to accommodate the electrode assembly 20, electrolyte and other components. An opening can be formed on one side of the flexible housing 10 for injecting electrolyte and the electrode assembly 20 into the housing.

[0107] Electrode terminals may be further provided on the flexible housing 10, and the electrode assembly 20 is a component where an electrochemical reaction occurs in the battery cell 100. One or more electrode assemblies 20 may be contained in the flexible housing 10. The electrode assembly 20 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly 20, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive electrode tab and the negative electrode tab may be located together at one end of the main body or at both ends of the main body, respectively. During the charge and discharge process of the battery device 200, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0108] The positive electrode sheet may include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.

[0109] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0110] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, titanium, silver surface treated aluminum or stainless steel, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0111] As an example, when the battery cell 100 of the embodiment of the present application is a lithium-ion battery, the positive electrode active material may include at least one of the following materials: phosphate, layered transition metal oxide and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxide and their respective modified compounds, which is beneficial to improve the energy density of the battery cell 100. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode film layers can also be used. These positive electrode active materials can be used alone or in combination of two or more.

[0112] Examples of phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0113] Layered transition metal oxides include those of the general formula Li a Ni b Co c M d O e A f At least one of the compounds and modified compounds thereof. 0.8≤a≤1.2, 0.3≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes at least one of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes at least one of N, F, S and Cl. Optionally, 0.5≤b<1, further optionally, 0.75≤b≤0.98.

[0114] Examples of layered transition metal oxides may include, but are not limited to, lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 )、LiNi 0.9 Co 0.05 Mn 0.05 O2 (also referred to as Ni90), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0115] When the battery cell 100 of the embodiment of the present application is a sodium ion battery, the positive electrode active material may include but is not limited to at least one of sodium-containing transition metal oxides, polyanion materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0116] As an example, the positive electrode active material for sodium ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, NaNi 1 / 2 Ti 1 / 2 O2、NaNi 1 / 2 Mn 1 / 2 O2、Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2、NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, general formula X p M' q (PO4) r O x Y 3-x In the general formula X p M' q (PO4) r O x Y 3-x , 0<p≤4, 0<q≤2, 1≤r≤3, 0≤x≤2, X includes at least one of H+, Li+, Na+, K+ and NH4+, M' is a transition metal cation, optionally at least one of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halogen anion, optionally at least one of F, Cl and Br.

[0117] In the embodiments of the present application, the modified compounds of the above-mentioned positive electrode active materials can be doping modification and / or surface coating modification of the positive electrode active materials, such as carbon coating modification, fast ion conductor coating modification, etc.

[0118] The battery cell 100 is accompanied by the deintercalation and consumption of active ions such as Li during the charge and discharge process, and the molar content of Li is different when the battery cell 100 is discharged to different states. In the examples of the positive electrode active materials in the present application, the molar content of Li is the initial state of the material, that is, the state before feeding. The positive electrode active material is used in the battery system, and the molar content of Li may change after charge and discharge cycles.

[0119] In the examples of the present application regarding the positive electrode active materials, the molar content of oxygen O is only a theoretical value. The release of oxygen from the lattice will cause the molar content of oxygen O to change. In reality, the molar content of oxygen O will fluctuate.

[0120] In the embodiments of the present application, the content of the elements in the positive electrode active material is a well-known meaning in the art, and can be detected by equipment and methods well-known in the art, for example, with reference to EPA 6010D-2014, tested by inductively coupled plasma atomic emission spectrometry, and measured by plasma atomic emission (ICP-OES, instrument model: Thermo ICAP7400). First, weigh 0.4 g of the positive electrode active material and add 10 ml (50% concentration) of aqua regia thereto. Then place it on a plate at 180 ° C for 30 minutes. After digestion on the plate, dilute to a volume of 100 mL, and use the standard curve method for quantitative testing.

[0121] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, or a carbon foam. When the foamed metal is used as the positive electrode, the positive electrode film layer may not be provided on the surface of the foamed metal, but of course, a positive electrode film layer may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0122] In some embodiments, the positive electrode film layer may further optionally include a positive electrode conductive agent. The present application embodiment has no particular restrictions on the type of the positive electrode conductive agent. As an example, the positive electrode conductive agent includes at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode film layer is ≤5wt%.

[0123] In some embodiments, the positive electrode film layer may also optionally include a positive electrode binder. The embodiment of the present application has no particular restrictions on the type of positive electrode binder. As an example, the positive electrode binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylic resin. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode film layer is ≤5wt%.

[0124] The positive electrode film layer is usually formed by coating the positive electrode slurry on the positive electrode current collector, drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, optional conductive agent, optional binder and any other components in a solvent and stirring them evenly. The solvent can be N-methylpyrrolidone (NMP), but is not limited thereto.

[0125] In some embodiments, the negative electrode may be a negative electrode plate, which may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0126] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0127] As an example, the negative electrode current collector may be a metal foil, a foamed metal or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0128] As an example, the negative electrode active material may adopt the negative electrode active material for the battery cell 100 known in the art. As an example, the negative electrode active material may include at least one of the following materials: a carbon material (for example, the carbon material includes at least one of artificial graphite, natural graphite, soft carbon, and hard carbon), a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material may include at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material may include at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other traditional materials that can be used as a negative electrode film layer of a battery may also be used. These negative electrode film layers may be used alone or in combination of two or more.

[0129] In some embodiments, the negative electrode active material includes silicon, which may be present in the form of a silicon-based material, such as a silicon-based material that may include at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon compounds, silicon-nitrogen compounds, and silicon alloys. The introduction of silicon can increase the energy density of the battery cell 100.

[0130] In some embodiments, the mass content of silicon in the negative electrode film layer is 1wt% to 32wt%, optionally 2wt% to 19wt%, and further optionally 6wt% to 13wt%. In the battery cell 100 system, when the mass content of silicon is within the above range, the energy density of the battery cell 100 can be improved.

[0131] In the embodiments of the present application, the mass content of silicon in the negative electrode film layer has a meaning well known in the art and can be detected by using equipment and methods well known in the art. For example, the negative electrode plate is immersed in a solvent such as water, the negative electrode active material is separated from the negative electrode current collector, and the negative electrode active material is obtained by filtration. The negative electrode active material is measured using an ICAP7400 inductively coupled plasma-emission spectrometer of ThermoFisher Scientific, USA, and with reference to GB / T30902-2014 standard to obtain the silicon content.

[0132] In some embodiments, the negative electrode film layer may further optionally include a negative electrode conductive agent. The embodiment of the present application has no particular restrictions on the type of the negative electrode conductive agent. As an example, the negative electrode conductive agent may include at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the negative electrode conductive agent in the negative electrode film layer is ≤5wt%.

[0133] In some embodiments, the negative electrode film layer may also optionally include a negative electrode binder. The embodiment of the present application has no particular restrictions on the type of negative electrode binder. As an example, the negative electrode binder may include at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA) and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage of the negative electrode binder in the negative electrode film layer is ≤5%.

[0134] In some embodiments, the negative electrode film layer may further include other additives. As an example, the other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of the other additives in the negative electrode film layer is ≤ 2wt%.

[0135] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0136] In some embodiments, the separator includes a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0137] The embodiments of the present application have no particular restrictions on the type of isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.

[0138] In some embodiments, the material of the isolation membrane may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane may be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0139] In some embodiments, the isolation membrane may include a porous base membrane and a coating layer disposed on at least one side of the porous base membrane, and the coating layer may include at least one of inorganic particles or organic particles.

[0140] The porous base membrane may include one or more of polyethylene and polypropylene.

[0141] The inorganic particles have good heat resistance and can improve the heat resistance of the separator as a whole. The inorganic particles will not undergo oxidation and reduction reactions with metal dendrites within the operating voltage range of the sodium ion battery. In other words, the inorganic particles are configured not to undergo oxidation and reduction reactions with alkali metals and / or alkaline earth metals at the nominal voltage of the sodium ion battery.

[0142] In some embodiments, the inorganic particles include one or more of boehmite γ-AlOOH, aluminum oxide Al2O3, aluminum hydroxide Al(OH)3, barium sulfate BaSO4, magnesium oxide MgO, magnesium hydroxide Mg(OH)2, calcium oxide CaO, cerium oxide CeO2, zirconium titanate SrTiO3, barium titanate BaTiO3, and magnesium fluoride MgF2.

[0143] In some embodiments, the organic particles include at least one of polystyrene, polyethylene, polyimide, melamine resin, phenolic resin, polypropylene, polyester (e.g., polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), polyphenylene sulfide, polyaramid, polyamideimide, polyimide, copolymer of butyl acrylate and ethyl methacrylate, and mixtures thereof.

[0144] In some embodiments, the battery cell 100 further includes an electrolyte.

[0145] During the charge and discharge process of the battery cell, active ions are embedded and released back and forth between the positive electrode and the negative electrode, and the electrolyte plays a role in conducting active ions between the positive electrode and the negative electrode. The present application embodiment has no particular limitation on the type of electrolyte, which can be selected according to actual needs.

[0146] The electrolyte includes electrolyte salt and solvent. The types of electrolyte salt and solvent are not specifically limited and can be selected according to actual needs.

[0147] In some embodiments, the electrolyte may also optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high temperature performance, and additives that improve battery low temperature power performance.

[0148] For example, the additive includes at least one of a cyclic carbonate compound containing an unsaturated bond, a sulfate compound, a sulfite compound, a sultone compound, a disulfonic acid compound, a nitrile compound, an aromatic compound, an isocyanate compound, a phosphazene compound, an acid anhydride, a cyclic acid anhydride compound, a phosphite compound, a phosphate compound, a borate ester, and a carboxylate compound.

[0149] In the related art, the electrode assembly 20 of the battery cell 100 is arranged in the flexible shell 10, and the flexible shell 10 itself is constructed of high-temperature resistant material. In the event of thermal runaway, the damage to the flexible shell 10 is small, but the restraint ability to the battery cell 100 is poor. The high-temperature airflow generated by the electrode assembly 20 entrains the solid particles and liquid substances inside the flexible shell 10 to form a high-temperature gas and fire flow that sprays out of the flexible shell 10. The protective effect of the flexible shell 10 is limited, and the spraying direction of the high-temperature gas and fire flow cannot be controlled, which will cause damage to the insulating interface of the battery device 200 and easily cause secondary damage.

[0150] Based on this, the present application proposes a battery cell 100, in which a pressure relief zone 121 is set on at least the circumferential surface 12 of the flexible shell 10, so that the battery cell 100 can achieve directional pressure relief in the pressure relief zone 121, so that the high-temperature gas and fire flow when the battery cell 100 has thermal runaway can be discharged from the pressure relief zone 121, thereby guiding the ejection direction of the gas and fire flow, thereby reducing the probability of insulation interface damage and secondary damage caused by thermal runaway, delaying the spread speed of thermal runaway, and improving the reliability of the battery cell 100.

[0151] Reference below Figure 1-Figure 14 A battery cell 100 , a battery device 200 , and an electric device 300 according to an embodiment of the present application are described.

[0152] like Figure 3 , Figure 5 and Figure 7 As shown, the present application provides a battery cell 100 , including: a flexible shell 10 and an electrode assembly 20 , wherein the electrode assembly 20 is disposed in the flexible shell 10 .

[0153] Among them, combined Figure 4 , Figure 6 as well as Figure 8As shown, the flexible shell 10 has a side surface 11 opposite to the large surface of the electrode assembly 20, and a circumferential surface 12 avoiding the large surface, and the circumferential surface 12 is circumferentially connected to the side surface 11 around the electrode assembly 20; at least the circumferential surface 12 is provided with a pressure relief area 121.

[0154] Specifically, the electrode assembly 20 may include one or more bare cells, and the bare cells may be constructed as rolled cores or stacked cores. During the stacking or winding of the bare cells, the surface with the largest surface area corresponds to the large surface of the electrode assembly 20, while other surfaces with smaller surface areas are arranged around the large surface and used to define the peripheral surface of the electrode assembly 20. The corresponding flexible shell 10 is used to accommodate the electrode assembly 20, and the flexible shell 10 has a side surface 11 opposite to the large surface and a circumferential surface 12 opposite to the peripheral surface.

[0155] Furthermore, the present application sets a pressure relief zone 121 on at least the circumferential surface 12, that is, the pressure relief zone 121 can be set on one side surface 11, two side surfaces 11, one circumferential surface 12, multiple circumferential surfaces 12, or both the side surface 11 and the circumferential surface 12, etc., and through the setting of the pressure relief zone 121, the battery cell 100 can be pressure-relieved through the pressure relief zone 121, and the pressure relief zone 121 can be set on a reasonable surface of the flexible shell 10, so that the battery cell 100 can be pressure-relieved through the pressure relief zone 121, and the safety protection of the battery cell 100 is achieved. By releasing pressure through the pressure relief zone 121, directional pressure relief of the battery cell 100 can be achieved, that is, pressure relief is only performed through the pressure relief zone 121. During the pressure relief process, the emissions inside the battery cell 100 can be guided to achieve orderly discharge.

[0156] According to the battery cell 100 of the embodiment of the present application, by setting the pressure relief area 121 on the flexible shell 10 to achieve directional pressure relief of the battery cell 100 during thermal runaway, the high-temperature gas and fire flow inside the battery cell 100 can be discharged in an orderly manner, so as to reduce the damage to the insulation interface of the battery device 200, reduce secondary damage, and improve the reliability of the battery cell 100 and even the battery device 200.

[0157] The insulating interface of the battery device 200 includes: the insulating structure between adjacent battery cells 100, the insulating structure between adjacent battery packs 500, the insulating structure between the battery pack 500 and surrounding components, etc., and the orderly discharge of the high-temperature gas and fire flow can reduce the impact on the insulating interface when the battery cell 100 is depressurized, thereby reducing the probability of secondary damage and improving reliability.

[0158] Combination Figure 3 , Figure 5 as well as Figure 7As shown, according to some embodiments of the present application, the pressure relief area 121 includes a weak portion 122 disposed on the circumferential surface 12 , and the weak portion 122 is configured to rupture to relieve pressure when the pressure in the flexible shell 10 exceeds a pressure threshold.

[0159] Specifically, the weak portion 122 can be formed into a weakened connection structure such as a notch. When the internal pressure of the flexible shell 10 exceeds the pressure threshold, the weakened connection structure can preferentially suffer structural damage (i.e., rupture) to form a pressure relief port on at least one surface of the flexible shell 10, and achieve directional pressure relief through the pressure relief port.

[0160] Therefore, through the setting of the weak portion 122, the pressure relief area 121 formed on the circumferential surface 12 can release pressure in time when the battery cell 100 has thermal runaway, thereby improving reliability. At the same time, the pressure relief portion 520 is located on the circumferential surface 12, and the position of the pressure relief portion 520 is more reasonable, so that directional pressure relief along the circumferential surface 12 can be achieved. The pressure relief direction is reasonable, which can reduce the impact on surrounding components, especially adjacent battery cells 100, during the pressure relief process, and further improve the reliability of the battery cell 100.

[0161] It should be pointed out that the flexible shell 10 is coated on the outside of the electrode assembly 20. The flexible shell 10 can be constructed as a winding coating structure, and a fold can be formed on the circumferential surface 12 or the side surface 11, and the weak portion 122 can be arranged on the circumferential surface 12. For example, the weak portion 122 can be constructed as a weakened connection structure, and at least part of the fold is connected by a weakened connection structure, or the weak portion 122 can be arranged separately, and the pressure relief zone 121 and the fold can be located on the same surface, or the pressure relief zone 121 and the fold can be located on different surfaces.

[0162] like Fig. 9 , Fig.10 as well as Fig.11 As shown, according to some embodiments of the present application, the film material of the flexible housing 10 is constructed as a stacked multi-layer film structure and includes at least a metal barrier layer a, and the weak portion 122 is formed in the metal barrier layer a, or the weak portion 122 extends and penetrates at least a portion of the metal barrier layer a.

[0163] That is, in some embodiments, the weak portion 122 is formed on the metal barrier layer a, so that the structural strength of the area where the weak portion 122 is located is lower than the structural strength of other areas, so that the area can be ruptured preferentially to achieve directional pressure relief. In other embodiments, the weak portion 122 is formed on the side of the flexible shell 10 away from the electrode assembly 20, and extends toward the metal barrier layer a, and penetrates at least part of the metal barrier layer a, so that the structural strength of the area where the weak portion 122 is located is lower than the structural strength of other areas, so that the area can be ruptured preferentially to achieve directional pressure relief.

[0164] Specifically, the film material of the flexible shell 10 refers to the material of the flexible shell 10 itself, and the film material itself is constructed as a multi-layer film structure, so as to improve the structural strength of the flexible shell 10 through the metal barrier layer a in the multi-layer film structure, reduce the probability of the electrode assembly 20 piercing the flexible shell 10, and improve the reliability of the battery cell 100. The weak portion 122 is formed on the metal barrier layer a, or penetrates the metal barrier layer a, which can reduce the processing difficulty of the weak portion 122 and make the stability and reliability of the weak portion 122 higher.

[0165] Combination Figure 4 , Figure 6 , Figure 8 as well as Fig.12 As shown, according to some embodiments of the present application, the weak portion 122 is configured as a notch, and the notch penetrates at least a portion of the metal barrier layer a.

[0166] Specifically, the weak portion 122 can be constructed as a notch, and the notch can be processed on the circumferential surface 12 or the side surface 11 of the flexible shell 10 by laser etching, knife scratching, etc., and the notch penetrates at least a portion of the metal barrier layer a, so that when the internal pressure of the flexible shell 10 acts on the area where the notch is located, the notch can be ruptured preferentially to achieve directional pressure relief.

[0167] Therefore, in the embodiment where the weak portion 122 is constructed as a notch, the notch only penetrates at least a portion of the metal barrier layer a, and the notch extends from a side surface of the flexible shell 10 away from the electrode assembly 20 toward a side surface of the flexible shell 10 adjacent to the electrode assembly 20, thereby achieving structural weakening of a partial area to form the weak portion 122. At the same time, the insulation effect between the metal barrier layer a and the interior of the flexible shell can remain stable, and the reliability and stability of the battery cell 100 can also be improved.

[0168] like Figure 3-Figure 8 As shown, according to some embodiments of the present application, the contour shape of the notch is one or more of a circle, an ellipse, a rectangle, a straight line, and a Z shape.

[0169] Specifically, in Figure 3 and Figure 4 In the embodiment shown, the notch is in the shape of a straight line, and the notch extends along the length direction of the circumferential surface 12 or the side surface 11, and is located on one side of the fold of the flexible housing 10. Figure 5 and Figure 6 In the embodiment shown, the notch is in the shape of a straight line, and the notch extends along the width direction of the circumferential surface 12 or the side surface 11, and is located on both sides of the fold of the flexible housing 10. Figure 7 and Figure 8 In the illustrated embodiment, the notch is circular in shape, and the notch may be located on both sides of the fold of the flexible housing 10 .

[0170] That is to say, the present application does not impose any specific restrictions on the structural shape of the notch, and those skilled in the art can process a notch of a suitable shape on a suitable surface of the flexible housing 10 according to the notch opening requirements.

[0171] Thus, by providing a notch of a suitable shape as the weak portion 122 , not only can the processing difficulty be reduced to reduce the production cost of the battery cell 100 , but the notch can also be provided at a suitable position on a suitable surface to achieve directional pressure relief, which can also further improve the reliability of the battery cell 100 .

[0172] According to some embodiments of the present application, there are a plurality of notches, which are arranged at intervals on the circumferential surface 12 or the side surface 11 of the flexible shell 10 .

[0173] Specifically, in an embodiment where the notch is in a straight line and extends along the length direction of the circumferential surface 12 or the side surface 11 where the notch is located, there may be multiple notches and they may be spaced apart in the width direction of the circumferential surface 12 or the side surface 11 where the notch is located; in an embodiment where the notch is in a straight line and extends along the width direction of the circumferential surface 12 or the side surface 11 where the notch is located, there may be multiple notches and they may be spaced apart in the length direction of the circumferential surface 12 or the side surface 11 where the notch is located; in an embodiment where the notch is a closed figure such as a circle or an ellipse, the notches may be spaced apart in the length direction and the width direction of the circumferential surface 12 or the side surface 11 where the notch is located.

[0174] Therefore, by setting a plurality of notches at intervals on the circumferential surface 12 or the side surface 11, rapid pressure relief can be achieved under the premise of achieving directional pressure relief (i.e., the direction of the surface where the notches are located) to reduce the impact during the pressure relief process, and the force distribution on the surface where the multiple notches are located is more uniform, and the pressure relief response speed and reliability can also be higher.

[0175] like Fig. 9 and Fig.12 As shown, according to some embodiments of the present application, the thickness of the film material of the flexible housing 10 is D1, the notch depth is D2, and 1 / 3≤D1 / D2≤2 / 3 is satisfied.

[0176] For example, if the film thickness is 3 mm, the notch depth is 1 mm to 2 mm (including the end points).

[0177] In this way, the notch depth is made not less than one-third of the film material thickness, which can avoid the notch depth being too shallow, so that the weak portion 122 has a better preferential rupture effect than other areas of the flexible shell 10, and the reliability and stability of the pressure relief zone 121 are better. At the same time, the notch depth is made not more than two-thirds of the film material thickness, which can avoid the notch being too deep, so as to take into account the structural strength of the flexible shell 10 and reduce the probability of false triggering of the weak portion 122.

[0178] like Fig.10 As shown, according to some embodiments of the present application, the film material of the flexible shell 10 includes: a metal barrier layer a, a first plastic barrier layer b located on the side of the metal barrier layer a facing the electrode assembly 20, and a second plastic barrier layer c on the side away from the electrode assembly 20, the metal barrier layer a includes a main body area a1 and a weak area a2 corresponding to the weak portion 122, and the weak area a2 is made of a different material from the main body area a1.

[0179] Specifically, the film material of the flexible shell 10 is constructed as a symmetrical structure, that is, the first plasticized barrier layer b and the second plasticized barrier layer c are respectively arranged on the side of the metal barrier layer a facing the electrode assembly 20 and the side away from the electrode assembly 20. The materials of the first plasticized barrier layer b and the second plasticized barrier layer c can be the same or different, but both are constructed as plastic parts with certain structural strength and insulation properties, so as to improve the structural strength of the flexible shell 10 while achieving insulation between the electrode assembly 20 and the metal barrier layer a, and between the metal barrier layer a and external components, thereby improving the insulation reliability and stability of the battery cell 100.

[0180] Furthermore, a first adhesive layer d is arranged between the first plasticized barrier layer b and the metal barrier layer a, and a second adhesive layer e is arranged between the second plasticized barrier layer c and the metal barrier layer a, so that the connection strength and structural stability between the first plasticized barrier layer b and the metal barrier layer a, and between the second plasticized barrier layer c and the metal barrier layer a are higher, and the materials between the weak area a2 and the main area a1 are different, and the structural strength of the main area a1 is higher than the structural strength of the weak area a2, so that the weak area a2 with lower structural strength is formed into a weak portion 122, and the weak portion 122 can rupture preferentially in the main area a1 when the internal pressure of the flexible shell 10 exceeds the pressure threshold, so as to achieve directional pressure relief.

[0181] That is to say, in some embodiments, the weak portion 122 of the present application is defined by the weak area a2 of the metal barrier layer a, and the weak area a2 and the main body area a1 are made of different materials to achieve differentiated settings of the structural strength between the weak portion 122 and the main body area a1. While achieving the above-mentioned technical effects, the outer surface of the flexible shell 10 can be smoother, the surface flatness of the battery cell 100 can be improved, and the probability of scratches between surrounding components can be reduced.

[0182] like Fig.11 As shown, according to some embodiments of the present application, the film material of the flexible shell 10 includes: a metal barrier layer a, a first plastic barrier layer b located on the side of the metal barrier layer a facing the electrode assembly 20, and a second plastic barrier layer c on the side away from the electrode assembly 20, the metal barrier layer a includes a main body area a1 and a weak area a2 corresponding to the weak portion 122, and the thickness of the weak area a2 is less than the thickness of the main body area a1.

[0183] Specifically, the structure of the weak portion 122 of the embodiment of the present application is not limited to the above-mentioned notches or the weak area a2 and the main body area a1 using different materials. The main body area a1 and the weak area a2 can also be made of the same material, but the thickness of the weak area a2 is smaller than the thickness of the main body area a1. It is also possible to achieve a differentiated setting of the structural strength between the main body area a1 and the weak area a2, thereby achieving the same technical effect as the above-mentioned embodiment.

[0184] It can be understood that the weak portion 122 of the present application is defined by the weak area a2 of the metal barrier layer a, and the weak area a2 has a different thickness from the main area a1, so as to achieve a differentiated setting of the structural strength between the weak portion 122 and the main area a1. While achieving the above-mentioned technical effects, it can also reduce the processing difficulty of the thinned portion and reduce material costs.

[0185] like Fig.11 As shown, according to some embodiments of the present application, the film material also includes: a filling layer f, the filling layer f is located between the first plasticized barrier layer b and the metal barrier layer a, and fills the weak area a2, and / or the filling layer f is located between the second plasticized barrier layer c and the metal barrier layer a, and is used to fill the weak area a2.

[0186] That is to say, the thickness of the weak area a2 is thinned relative to the main area a1 to define a weak portion 122, and the thinned portion of the weak area a2 relative to the main area a1 can be located on the side away from the electrode assembly 20, then the filling layer f is filled on the side of the weak area a2 away from the electrode assembly 20, the thinned portion can also be located on the side facing the electrode assembly 20, then the filling layer f is filled on the side of the weak area a2 facing the electrode assembly 20, the weak portion 122 can also include a first part and a second part, the first part is located on the side of the weak area a2 facing the electrode assembly 20, the second part is located on the side of the weak area a2 away from the electrode assembly 20, and the filling layer f is provided in both the first part and the second part.

[0187] Therefore, by setting the filling layer f, the flatness of the side surface of the flexible shell 10 facing the electrode assembly 20 and some surfaces away from the electrode assembly 20 can be improved, the probability of scratches between the flexible shell 10 and surrounding components (such as scratches on the electrode assembly 20) can be reduced, and the reliability of the flexible shell 10 can be improved.

[0188] According to some embodiments of the present application, the battery cell is any one of a lithium iron phosphate battery cell, a ternary lithium battery cell and a solid-state battery cell.

[0189] That is, in some embodiments, the battery cell is configured as a lithium iron phosphate battery, in some embodiments, the battery cell is configured as a ternary lithium battery cell, and in some embodiments, the battery cell is configured as a solid-state battery cell.

[0190] The solid-state battery cell may be, but is not limited to, a polymer solid-state battery cell, an oxide solid-state battery cell, a sulfide solid-state battery cell, a halide solid-state battery cell, etc. The solid-state battery cell may also be a semi-solid-state battery cell or a fully solid-state battery cell.

[0191] In this way, in the embodiment of the present application constructed as a lithium iron phosphate battery cell, the reliability of the battery cell can be improved and the cycle life of the battery cell can be extended. In the embodiment of the present application constructed as a ternary lithium battery cell, the energy density of the battery cell can be improved and the cruising range can be increased. In the embodiment of the present application constructed as a solid-state battery cell, not only the energy density can be improved, but also the reliability can be improved.

[0192] According to some embodiments of the present application, when the battery cell 100 is a lithium iron phosphate (LiFeO4) battery cell, the ratio of the positive electrode active material, the positive electrode binder and the positive electrode conductive agent in the positive electrode material of the battery cell 100 is 96: (1-3): (1-3); when the battery cell 100 is a ternary lithium battery cell, and the ratio of the positive electrode active material, the positive electrode binder and the positive electrode conductive agent in the positive electrode material of the battery cell 100 is 96: (2-3): (1-2).

[0193] It can be understood that when the battery cell 100 is a lithium iron phosphate battery cell, in the positive electrode material of the battery cell 100, the positive electrode active material accounts for 96 parts of the total weight of the positive electrode material, the binder accounts for 1 to 3 parts of the total weight of the positive electrode material (for example, it can include but is not limited to 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, etc.), and the conductive agent accounts for 1 to 3 parts of the total weight of the positive electrode material (for example, it can include but is not limited to 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, etc.).

[0194] For example, when the battery cell 100 is a lithium iron phosphate battery cell, the positive electrode active material is LFP (which may refer to LiFePO4, i.e., lithium iron phosphate), the binder may be PVDF (polyvinylidene fluoride), and the conductive agent may be conductive carbon black, wherein LFP:PVDF:conductive carbon black may be 96:2:2, that is, the total weight of the positive electrode active material is 100 parts, LFP accounts for 96 parts, PVDF accounts for 2 parts, and conductive carbon black also accounts for 2 parts. The weight unit of the positive electrode active material may be grams.

[0195] When the battery cell 100 is a ternary battery cell, in the positive electrode material of the battery cell 100, the positive electrode active material accounts for 96 parts of the total weight of the positive electrode material, the binder accounts for 2-3 parts of the total weight of the positive electrode material (for example, including but not limited to 2, 2.2, 2.5, 2.8, 3, etc.), and the conductive agent accounts for 1-2 parts of the total weight of the positive electrode material (for example, including but not limited to 1, 1.2, 1.5, 1.8, 2, etc.). Among them, the ternary battery cell can be but not limited to nickel cobalt manganese lithium oxide system, nickel cobalt aluminum oxide lithium oxide system, etc.

[0196] For example, the ternary material of the ternary battery cell can be eight series LiNi 0.8 Co 0.1 Mn 0.1 O2, the weight ratio of the positive electrode active material, binder and conductive agent is 96:2.5:1.5, that is, the total weight of the positive electrode material is divided into 100 parts, eight series LiNi 0.8 Co 0.1 Mn 0.1 O2 accounts for 96 parts, the binder accounts for 2.5 parts, and the conductive agent accounts for 1.5 parts.

[0197] In the above technical solution, when the battery cell 100 is a lithium iron phosphate battery cell, a high proportion of positive electrode active material means that more substances capable of electrochemical reactions can be accommodated in a limited electrode assembly, which is beneficial to increasing the capacity and energy density of the battery device 100, so that the lithium iron phosphate battery cell can output a higher amount of electricity in a relatively small volume and weight, meeting the application scenario with certain requirements for energy density. The amount of binder and conductive agent used in the above range can reduce the cost of auxiliary materials, thereby reducing the overall cost of the battery device 100. When the battery cell 100 is a ternary battery cell, since the structure and surface properties of the ternary material itself are relatively complex, the use of the positive electrode active material, binder, and conductive agent in the above amount ratio is beneficial to ensure good bonding between the positive electrode active material particles and between the active material and the current collector, thereby improving the mechanical stability and integrity of the electrode assembly, and reducing the risk of active material shedding and electrode pulverization during charging and discharging, and extending the cycle life of the battery device 100.

[0198] like Figure 2 , Fig.13 as well as Fig.14 As shown, the present application provides a battery device 200, including: a box body 400 and a battery pack 500, there is at least one battery pack 500, the battery pack 500 includes: at least one battery cell 100 in the above embodiment and a covering shell 510, at least one side surface of the covering shell 510 has a pressure relief portion 520.

[0199] See also Fig.13 and Fig.14 As shown, a containing space is formed in the box body 400, and one or more battery packs 500 are arranged in the containing space. One or more battery cells 100 are arranged inside the covering shell 510 of each battery pack 500, and the battery cell 100 is constructed as the battery cell 100 using the flexible shell 10 as mentioned above.

[0200] Among them, the covering shell 510 is at least used to cover at least one of the multiple circumferential surfaces 12 and two side surfaces 11 of the battery cell 100, and a weak portion 122 is provided on at least one circumferential surface 12 of the battery cell 100, and a pressure relief portion 520 is formed on at least one side of the covering shell 510, such as the pressure relief portion 520 is opposite to the weak portion 122, or the pressure relief portion 520 is located on the first surface of the covering shell 510, and the weak portion 122 is opposite to the second surface of the covering shell 510, and the first surface is adjacent to the second surface.

[0201] According to the battery device 200 of the embodiment of the present application, by providing a pressure relief portion 520 that cooperates with the pressure relief area 121 on the covering shell 510, when the battery cell 100 has thermal runaway, the high-temperature gas and fire flow discharged through the pressure relief area 121 (weak portion 122) can be further released outward through the pressure relief portion 520, so as to achieve directional discharge of the high-temperature gas and fire flow through the cooperation between the weak portion 122 and the pressure relief portion 520, so as to improve the reliability of the battery device 200.

[0202] Combination Fig.13 and Fig.14 As shown, according to some embodiments of the present application, the covering shell 510 includes a first plate 511 and a second plate 512 located on both sides of the first plate 511 , a pressure relief portion 520 is formed on the first plate 511 , and the pressure relief area 121 is at least partially opposite to the pressure relief portion 520 .

[0203] Specifically, the first plate 511 and the second plates 512 located on both sides of the first plate 511 define a generally U-shaped covering shell 510, so that the first plate 511 of the covering shell 510 can be opposite to a circumferential surface 12 of the battery cell 100, and the two second plates 512 can be opposite to the two side surfaces 11 of the battery cell 100 respectively, and the weak portion 122 formed on the circumferential surface 12 can be at least partially opposite to the pressure relief portion 520 formed on the first plate 511.

[0204] It should be pointed out that the pressure relief area 121 is at least partially opposite to the pressure relief portion 520 , which means that the weak portion 122 formed on the circumferential surface 12 is projected toward the first plate 511 , and the projection contour at least partially overlaps with the contour of the pressure relief portion 520 .

[0205] In this way, on the one hand, the gas and fire flow generated after the thermal runaway of the battery cell 100 can be discharged in a direction and orderly to reduce damage, especially secondary damage. On the other hand, the connection path between the pressure relief area 121 and the pressure relief part 520 is shorter, which can achieve rapid discharge. At the same time, the gas and fire flow stays in the covering shell 510 for a shorter time, which has less impact on other battery cells 100 around the thermal runaway battery cell 100, and can further reduce the spread speed of thermal runaway, thereby improving the reliability of the battery pack 500 and the battery device 200.

[0206] According to some embodiments of the present application, the second plate 512 is opposite to the side surface 11 , and a projection contour area of ​​the second plate 512 toward the side surface 11 of the flexible housing 10 is smaller than or equal to an area of ​​the side surface 11 .

[0207] Specifically, the circumferential surface 12 is defined to include a first surface and a second surface opposite thereto, the first surface is opposite to the first plate 511, the second surface is arranged away from the first plate 511, and the second surface is used to connect to the box body 400, the two sides of the first surface and the second surface are respectively the two side surfaces 11 of the battery cell 100, the two ends of the first surface and the second surface are respectively the other two circumferential surfaces 12 of the battery cell 100, and the second plate 512 is opposite to the side surface 11 to achieve limiting of the battery cell 100 in the direction of the second plate 512, and the area size of the surface of the second plate 512 opposite to the side surface 11 can be less than or equal to the area size of the side surface 11.

[0208] That is to say, in some embodiments, the size of the second plate 512 is consistent with the size of the side 11, and in other embodiments, the size of the second plate 512 is smaller than the size of the side 11. On the one hand, it can avoid the second plate 512 being too large, which makes the second surface unable to connect to the box 400, and can improve the fixation stability and reliability of the battery pack 500 in the box 400. On the other hand, the material used for the second plate 512 can be less, and the material cost of the battery pack 500 and the battery device 200 can also be reduced.

[0209] like Figure 3 and Fig.13 As shown, according to some embodiments of the present application, the first plate 511 is spaced apart from a side of the circumferential surface 12 having the weak portion 122 to define an exhaust passage 530 .

[0210] In this way, the high-temperature gas and fire flow generated after the weak part 122 ruptures can be first discharged to the exhaust channel 530, and after preliminary buffering through the exhaust channel 530, it can be discharged through the pressure relief part 520, which can reduce the pressure of the high-temperature gas and fire flow after flowing out of the pressure relief part 520, so as to reduce the impact and damage of the battery cell 100 after thermal runaway.

[0211] According to some embodiments of the present application, the first plate 511 is configured as a straight plate or a curved plate.

[0212] That is, in some embodiments, the first plate 511 is configured as a straight plate, and in other embodiments, the first plate 511 is configured as a curved plate.

[0213] According to some embodiments of the present application, there are multiple pressure relief portions 520 , and the multiple pressure relief portions 520 are arranged at intervals in the length direction and / or the width direction of the first plate 511 .

[0214] Thus, the multiple weak parts 122 on each battery cell 100 can all have corresponding pressure relief parts 520, so that the high-temperature gas and fire flow buffered by the exhaust channel 530 can be directly discharged through the corresponding pressure relief parts 520, thereby increasing the discharge speed and reducing the residence time of the high-temperature gas and fire flow in the exhaust channel 530 during the discharge process, so as to reduce the spread speed of thermal runaway between adjacent battery cells 100 in the battery pack 500 and improve the reliability of the battery pack 500.

[0215] According to some embodiments of the present application, the covering shell 510 is constructed as an aluminum shell or a stainless steel shell.

[0216] It can be understood that, in some embodiments, the covering shell 510 is constructed as an aluminum shell, and in other embodiments, the covering shell 510 is constructed as a stainless steel shell, so that the temperature resistance and structural strength of the covering shell 510 are much higher than those of the flexible shell. By using the covering shell 510 with a certain structural strength and rigidity to support and protect the battery cell 100 outside the battery cell 100, the structural strength of the battery pack 500 can be improved, and the thermal runaway propagation speed between adjacent battery packs 500 can be reduced, thereby improving the reliability of the battery device 200.

[0217] Combination Fig.14 As shown, according to some embodiments of the present application, the box body 400 has a bottom plate 410 , and the bottom plate 410 is connected to the battery cell 100 via an adhesive layer 420 .

[0218] Specifically, the bottom plate 410 of the box body 400 is connected to the second surface of the battery cell 100 via the adhesive layer 420 to fix the battery pack 500 on the box body 400 and improve the fixing stability and reliability of the battery pack 500.

[0219] Of course, in some embodiments, the adhesive layer 420 is also used to connect and fix the bottom plate 410 and the second plate 512 .

[0220] Combination Fig.14 As shown, according to some embodiments of the present application, the bottom plate 410 includes a cold plate, and the glue layer 420 is located between the cold plate and the plurality of battery cells 100 .

[0221] In some embodiments, the bottom plate 410 of the box body 400 is formed as a cold plate, and the cold plate is connected to the battery cell 100 through an adhesive layer 420. In other embodiments, a cold plate is arranged between the bottom plate 410 and the battery cell 100, and the cold plate is connected to the battery cell 100 through an adhesive layer 420.

[0222] That is to say, the adhesive layer 420 is constructed as structural adhesive, and the bottom plate 410 provided with a cold plate is connected to the battery cell 100. On the premise of achieving stable and reliable fixation of the battery pack 500 in the box body 400, the temperature of the battery pack 500 can also be regulated by the cold plate, so that the battery pack 500 can operate at a suitable temperature, which can improve the working stability and reliability of the battery pack 500, reduce the probability of overheating of the battery pack 500, and reduce the probability of thermal runaway of the battery pack 500, thereby improving the reliability of the battery pack 500 and even the battery device 200.

[0223] like Fig.14 As shown, according to some embodiments of the present application, the glue layer 420 includes: a glue layer body 421 and a glue overflow portion 422, the glue overflow portion 422 is located on the side of the glue layer body 421 facing the multiple battery cells 100, and is located between adjacent battery cells 100, and / or between the battery cells 100 and the second plate 512.

[0224] That is to say, when the structural adhesive is used to connect and fix the battery cell 100 and the cold plate, at least part of the glue layer 420 overflows between adjacent battery cells 100 and / or between the second plate 512 and the battery cell 100, and forms an overflow glue portion 422. By setting the overflow glue portion 422, not only the area between the glue layer 420 and the battery cell 100, and the area between the glue layer 420 and the second plate 512 can be increased to improve the fixation stability and reliability of the battery pack 500 on the box 400, but also the gap between adjacent battery cells 100 and between the battery cell 100 and the second plate 512 can be filled by the overflow glue portion 422 to achieve the limitation of the battery cell 100 and the covering shell 510, reduce the movement of the battery pack 500 in the box 400, and reduce the movement of the battery cell 100 in the covering shell 510.

[0225] As shown in the accompanying drawings, the battery cell 100 of the embodiment of the present application is constructed as a soft-pack battery cell, the electrode assembly 20 is arranged in the flexible shell 10, and a weak portion 122 is formed on at least the circumferential surface 12 of the flexible shell 10. The battery pack 500 includes at least one battery cell 100 of the embodiment of the present application, and the pressure relief portion 520 on the first plate 511 of the covering shell 510 is at least partially opposite to the weak portion 122, and the second plate 512 is opposite to the side surface 11 of the flexible shell 10. The bottom plate 410 of the box body 400 is constructed as a cold plate, or a cold plate is arranged above the bottom plate 410, and the cold plate is connected to the battery cell 100 through the glue layer 420, and the overflow glue portion 422 of the glue layer 420 overflows between adjacent battery cells 100, and / or between the battery cell 100 and the second plate 512.

[0226] The present application proposes an electric device 300, comprising: the battery device 200 in the above embodiment.

[0227] Furthermore, if Figure 1 As shown, the electrical equipment 300 can be a vehicle, and the battery device 200 can be integrated on the chassis of the vehicle, that is, the body structure is a split body, the upper body and the integrated intelligent chassis are assembled, and the battery device 200 forms a part of the integrated intelligent chassis, so that the top plate of the box body 400 can also participate in defining the body floor, which can save meaningless multi-layer plate stacking, reduce material costs, and make the space occupancy of the chassis more reasonable. The space inside the chassis for accommodating the battery device 200 is larger and the energy density is higher.

[0228] It is understandable that the electrical equipment 300 is constructed as a vehicle, that is, the vehicle adopts the above-mentioned battery device 200. The battery device 200 has a higher energy density and higher reliability, which can improve the driving safety of the vehicle while improving the cruising range of the vehicle.

[0229] Other structures and operations of the battery cell 100 , the battery device 200 and the electric device 300 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0230] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0231] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: Flexible housing (10); An electrode assembly (20) is disposed in the flexible housing (10); The flexible housing (10) has a side surface (11) opposite to the large surface of the electrode assembly (20), and a circumferential surface (12) avoiding the large surface, the circumferential surface (12) and the side surface (11) being connected circumferentially around the electrode assembly (20); at least the circumferential surface (12) is provided with a pressure relief area (121); The pressure relief zone (121) comprises a weak portion (122) arranged on the circumferential surface (12), the weak portion (122) being configured to rupture to relieve pressure when the pressure in the flexible shell (10) exceeds a pressure threshold, the film material of the flexible shell (10) being a stacked multi-layer film structure and comprising at least a metal barrier layer (a), the weak portion (122) being formed on the metal barrier layer (a), or the weak portion (122) extending and penetrating at least a portion of the metal barrier layer (a).

2. The battery cell according to claim 1, characterized in that: The weak portion (122) is configured as a notch, and the notch penetrates at least a portion of the metal barrier layer (a).

3. The battery cell according to claim 2, characterized in that: The outline shape of the notch is one or more of a circle, an ellipse, a rectangle, a straight line, and a Z shape.

4. The battery cell according to claim 2, characterized in that: The notches are multiple and are arranged at intervals on the circumferential surface (12) or the side surface (11).

5. The battery cell according to claim 2, characterized in that: The thickness of the film material of the flexible housing (10) is D1, the depth of the notch is D2, and 1 / 3≤D1 / D2≤2 / 3 is satisfied.

6. The battery cell according to claim 1, characterized in that: The film material of the flexible housing (10) comprises: a metal barrier layer (a), a first plastic barrier layer (b) located on the side of the metal barrier layer (a) facing the electrode assembly (20), and a second plastic barrier layer (c) located on the side away from the electrode assembly (20), the metal barrier layer (a) comprising a main body region (a1) and a weak region (a2) corresponding to the weak portion (122), the weak region (a2) and the main body region (a1) being made of different materials.

7. The battery cell according to claim 1, characterized in that: The film material of the flexible housing (10) comprises: a metal barrier layer (a), a first plastic barrier layer (b) located on a side of the metal barrier layer (a) facing the electrode assembly (20), and a second plastic barrier layer (c) located on a side away from the electrode assembly (20), wherein the metal barrier layer (a) comprises a main body region (a1) and a weak region (a2) corresponding to the weak portion (122), and the thickness of the weak region (a2) is less than the thickness of the main body region (a1).

8. The battery cell according to claim 7, characterized in that: The film material also includes: a filling layer (f), the filling layer (f) is located between the first plasticized barrier layer (b) and the metal barrier layer (a), and is filled in the weak area (a2), and / or the filling layer (f) is located between the second plasticized barrier layer (c) and the metal barrier layer (a), and is used to fill in the weak area (a2).

9. The battery cell according to any one of claims 1 to 8, characterized in that: The battery cell is any one of a lithium iron phosphate battery cell, a ternary lithium battery cell and a solid-state battery cell.

10. A battery device, characterized in that: include: box(400); A battery pack (500), the battery pack (500) being at least one, the battery pack (500) comprising: at least one battery cell according to any one of claims 1 to 9 and a covering shell (510), at least one side surface of the covering shell (510) having a pressure relief portion (520).

11. The battery device according to claim 10, characterized in that: The covering shell (510) comprises a first plate (511) and second plates (512) located on both sides of the first plate (511); the pressure relief portion (520) is formed on the first plate (511); and the pressure relief area (121) is at least partially opposite to the pressure relief portion (520).

12. The battery device according to claim 11, characterized in that: The second plate (512) is opposite to the side surface (11), and a projection contour area of ​​the second plate (512) toward the side surface (11) of the flexible housing (10) is less than or equal to an area of ​​the side surface (11).

13. The battery device according to claim 11, characterized in that: The first plate (511) is spaced apart from a side of the circumferential surface (12) having the weak portion (122) to define an exhaust passage (530).

14. The battery device according to claim 11, characterized in that: The first plate (511) is configured as a straight plate or a curved plate.

15. The battery device according to claim 10, characterized in that: There are a plurality of pressure relief portions (520), and the plurality of pressure relief portions (520) are arranged at intervals in the length direction and / or the width direction of the first plate (511).

16. The battery device according to claim 10, characterized in that: The covering shell (510) is constructed as an aluminum shell or a stainless steel shell.

17. The battery device according to claim 11, characterized in that: The box body (400) has a bottom plate (410), and the bottom plate (410) is connected to the battery cell via a glue layer (420).

18. The battery device according to claim 17, characterized in that: The bottom plate (410) comprises a cold plate, and the adhesive layer (420) is located between the cold plate and the battery cell.

19. The battery device according to claim 17, characterized in that: The glue layer (420) comprises: a glue layer body (421) and a glue overflow portion (422), wherein the glue overflow portion (422) is located on a side of the glue layer body (421) facing the battery cell and is located between adjacent battery cells and / or between the battery cell and the second plate (512).

20. An electrical equipment, characterized in that: include: The battery device according to any one of claims 10 to 19.

21. The electrical equipment according to claim 20, characterized in that: The electrical equipment is a vehicle.

22. The electrical equipment according to claim 21, characterized in that: The battery device is integrated into the chassis of the vehicle, and the top plate of the box (400) helps define the vehicle body floor.

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