Battery cell, battery device, and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device, the battery monomer comprises a shell, an electrode assembly, a pressure relief structure and a protection piece, the electrode assembly is accommodated in the shell, the shell comprises a first wall, the pressure relief structure is arranged on the first wall, the protection piece comprises a first area and a second area arranged around the first area, and the first area is arranged in the second area. The first area is arranged on the side, away from the electrode assembly, of the pressure relief structure; wherein the first area and the second area are detachably connected, and the connection strength of the first area and the first wall is smaller than that of the second area and the first wall. According to the battery monomer disclosed by the embodiment of the invention, the protection piece is arranged on one side of the first wall to prevent high-temperature and high-pressure substances discharged by other battery cells from directly splashing down to the first wall to cause corrosion and melt-through, so that the probability of thermal runaway chain reaction of the battery device is reduced; and gas discharged from the pressure relief structure can break through the first area to realize pressure relief.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell, a battery device, and an electrical device. Background Technology

[0002] With the continuous development of new energy technologies, batteries are increasingly being used in new energy vehicles, energy storage systems, and other fields. Generally, battery cells have a pressure relief structure on the top cover of the casing. This pressure relief structure can be opened when the battery cell is in an abnormal state to release high-temperature and high-pressure substances.

[0003] However, the high-temperature and high-pressure substances discharged through the pressure relief structure can easily splash onto adjacent battery cells, causing a thermal runaway chain reaction, or even leading to fire or explosion. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device that can protect the casing of the battery cell to reduce damage to the casing caused by high-temperature and high-pressure substances, reduce the probability of thermal runaway chain reaction, and improve the reliability and safety of the battery device.

[0005] In a first aspect, this application provides a battery cell, which includes a casing, an electrode assembly, a pressure relief structure, and a protective component. The electrode assembly is housed within the casing, which includes a first wall. The pressure relief structure is disposed on the first wall. The protective component includes a first region and a second region disposed around the first region. The first region is disposed on the side of the pressure relief structure away from the electrode assembly. The first region and the second region are detachably connected, and the connection strength between the first region and the first wall is less than the connection strength between the second region and the first wall.

[0006] In this embodiment, the battery cell has a protective component on one side of the first wall to form a high-temperature resistant shield, preventing high-temperature, high-pressure substances discharged from other cells from directly splashing onto the first wall and causing corrosion and meltdown, thereby reducing the probability of thermal runaway chain reaction in the battery device. The protective component also has a first region above the pressure relief structure that can be separated from the second region. When a battery cell malfunctions, the gas discharged from the pressure relief structure can break through the first region to relieve pressure, reducing the probability of overpressure inside the battery cell leading to an explosion.

[0007] In some alternative embodiments, the second region is connected to the first wall, and the first region is connected to the first wall through the second region.

[0008] In the above optional embodiments, the second region is directly connected to the first wall, and the first region is indirectly connected to the first wall, so that the connection strength between the second region and the first wall is greater, so that the first region can separate from the outer casing before the second region, thereby the pressure relief structure can normally achieve pressure relief to improve the safety of the battery cell.

[0009] In some alternative embodiments, the connection strength between the first region and the second region is less than the connection strength between the second region and the first wall.

[0010] In the above optional embodiments, when the pressure relief structure needs to relieve pressure, the first region can be separated from the second region under the impact of high-pressure gas, and the second region is still connected to the first wall to form a protective effect on the first wall, thereby reducing the damage to the first wall caused by high-temperature and high-pressure substances.

[0011] In some alternative embodiments, a weak structure is provided between the first region and the second region to allow the first region and the second region to be separably connected.

[0012] In the above optional embodiments, when the pressure relief structure needs to release pressure, the high-pressure gas rushes towards the protective component and directly impacts the first area. The weaker structure with lower strength can crack first to separate the first area from the second area. The separation of the first area exposes the pressure relief structure for smooth pressure release.

[0013] In some alternative embodiments, the shape of the weak structure is the same as that of the pressure relief structure and their geometric centers overlap.

[0014] In the above optional embodiments, after the weak structure breaks, the gap formed after the first region separates from the second region can more accurately expose the pressure relief structure, thereby shortening the release path of high-pressure gas and reducing the heat accumulation inside the battery cell.

[0015] In some alternative embodiments, the maximum distance between the boundary line of the weak structure and the boundary line of the pressure relief structure on a plane parallel to the first wall is less than 3 mm.

[0016] In the above optional embodiments, reducing the size difference between the weak structure and the pressure relief structure allows for the smooth release of high-pressure gas, reducing the exposure of other areas of the first wall and thus achieving a better protection effect.

[0017] In some alternative embodiments, the weak structure includes multiple connecting portions and a cutout portion disposed between two adjacent connecting portions, the multiple connecting portions being connected end to end to allow the first region and the second region to be separably connected.

[0018] In the above optional embodiments, the weak structure is in the form of a tear line. On the one hand, the hollow part can meet the small pressure relief requirements of the pressure relief structure without affecting the protective effect of the protective component on the first wall and the pressure relief structure. On the other hand, after the tear line is locally impacted and broken, it can more easily break along the preset traces where the beginning and end are connected, so that the first area can quickly separate from the second area to complete the pressure relief.

[0019] In some alternative embodiments, the length of the cutout portion is greater than the length of the connecting portion along the extension direction of the weak structure.

[0020] In the above optional embodiments, the hollowed-out portion accounts for a larger proportion of the weak structure, so that the weak structure is more susceptible to impact and the first region is separated from the second region, thereby smoothly completing the pressure relief.

[0021] In some alternative embodiments, the lengths of the connections are the same along the extension direction of the weak structure.

[0022] In the above optional embodiments, it is convenient to process and prepare the weak structure.

[0023] In some alternative embodiments, at least two connecting portions are distinguished in length along the extension direction of the weak structure.

[0024] In the above optional embodiments, the local strength of the weak structure can be adjusted by differentiating the lengths of the connecting parts, thereby making it easier to disconnect the preset area to accelerate the release of high-pressure gas.

[0025] In some alternative embodiments, the connection between the second region and the first wall includes at least one of bonding, welding, riveting, and fastener connection.

[0026] In the above optional embodiments, the second region is fixedly connected to the first wall to improve the connection strength between the second region and the first wall, reduce the probability of the first wall directly contacting high-temperature and high-pressure substances, and improve the safety of the battery cell.

[0027] In some alternative embodiments, the battery cell further includes electrode terminals, which are at least partially disposed on the first wall and electrically connected to the electrode assembly, and a second region has a clearance hole for the power terminal to pass through.

[0028] In the above optional embodiments, the clearance hole provided in the second region can assist in the installation and positioning of the protective component towards the first wall, thereby reducing the assembly difficulty between the protective component and the first wall.

[0029] In some alternative embodiments, the thickness of the protective element is less than the length of the electrode terminal extending out of the first wall, or the thickness of the protective element is equal to the length of the electrode terminal extending out of the first wall.

[0030] In the above optional embodiments, the protective component can be compatible with the portion of the electrode terminal extending out of the first wall, thereby reducing the space occupied by the protective component in the height direction of the battery cell and improving the integration of the battery cell.

[0031] In some alternative embodiments, the material of the protective element includes at least one of mica, aluminum silicate fiber, hydroxyapatite, polyimide, and polyethylene.

[0032] In the above optional embodiments, the protective component can withstand high-temperature and high-pressure substances below 1500°C without being melted through, thereby preventing the high-temperature and high-pressure substances from directly contacting the first wall and causing thermal runaway.

[0033] In some alternative embodiments, the thickness of the protective element is greater than or equal to 0.01 mm and less than or equal to 3 mm.

[0034] In the above optional embodiments, the protective component has sufficient thickness to prevent high-temperature and high-pressure substances from melting through the protective component and contacting the first wall, causing damage, and is controlled within a reasonable thickness range to reduce the impact on the assembly of battery cells and other components.

[0035] In some alternative embodiments, the thickness of the protective element is greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

[0036] In the above optional embodiments, the protective component occupies a reasonable space in the height direction of the battery cell and has sufficient protective effect, resulting in better economic benefits.

[0037] Secondly, this application provides a battery device, which includes a housing and at least one battery cell as provided in any embodiment of the first aspect, wherein the battery cell is housed within the housing.

[0038] Thirdly, this application provides an electrical device configured to receive electrical energy provided by a battery device as provided in any embodiment of the second aspect. Attached Figure Description

[0039] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0040] Figure 1 This is a schematic diagram of the structure of an electrical device according to an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of the structure of a battery device according to an embodiment of this application;

[0042] Figure 3 This is a schematic diagram of the structure of a battery cell pack according to an embodiment of this application;

[0043] Figure 4 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0044] Figure 5 for Figure 4 A schematic diagram of the exploded structure of a single battery cell;

[0045] Figure 6 This is a schematic diagram of the structure of a protective component according to an embodiment of this application;

[0046] Figure 7 for Figure 6 An enlarged structural diagram of point A in the protective component shown;

[0047] Figure 8 This is a schematic diagram showing the connection between the protective member and the first wall according to an embodiment of this application.

[0048] The accompanying drawings are not necessarily drawn to scale.

[0049] The specific marking information in the attached diagram is as follows:

[0050] 1000, vehicles;

[0051] 100. Battery assembly; 200. Controller; 300. Motor;

[0052] 10. Box body; 11. First box body section; 12. Second box body section;

[0053] 20. Battery cell pack; 21. Battery cell;

[0054] 211. Outer shell; 2111. First wall; 2112. Insulating patch; 212. Pressure relief structure; 213. Protective component; 2131. First region; 2132. Second region; 21321. Clearance hole; 2133. Weak structure; 21331. Connecting part; 21332. Hollowed-out part; 214. Electrode assembly; 215. Electrode terminal;

[0055] Z-axis of battery cell height. Detailed Implementation

[0056] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0061] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0062] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0063] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0064] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0065] A power battery can be composed of multiple battery cells arranged together. During use, when a fault occurs inside a battery cell, a large amount of gas will be generated, causing the internal pressure to increase rapidly. The battery cell is equipped with an explosion-proof valve on its top cover. The explosion-proof valve can open when the internal pressure of the battery cell is too high and release high-temperature and high-pressure gas and substances in a timely manner, which reduces the probability of the battery cell exploding to a certain extent, but still cannot completely prevent the battery cell from exploding.

[0066] Furthermore, when a battery cell inside a power battery accidentally explodes, the high-temperature and high-pressure substances released can easily splash onto other adjacent battery cells and cause corrosion and melting, which in turn can cause a chain reaction of thermal runaway caused by a rapid increase in the internal temperature of multiple battery cells.

[0067] To address the aforementioned issues, this application proposes a battery cell that can protect the casing with a pressure relief structure, preventing high-temperature and high-pressure substances from directly splashing onto the casing and causing melt-through, thereby reducing the probability of thermal runaway chain reaction in the battery and improving battery safety.

[0068] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0069] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0070] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0071] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0072] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0073] The solutions in this application can be applied to, but are not limited to, individual battery cells, as well as to battery devices including individual battery cells and electrical devices including individual battery cells and battery devices.

[0074] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0075] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0076] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0077] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0078] The battery device 100 mentioned in the embodiments of this application may include one or more battery cell groups 20 for providing voltage and capacity. A battery cell group may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0079] In some embodiments, a battery cell group is typically formed by arranging multiple battery cells; as an example, a battery cell group can be a battery module, which is formed by arranging and fixing multiple battery cells into an independent module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0080] In some embodiments, the battery device 100 may be a battery pack, which includes a housing and one or more battery cell groups 20 housed in the housing.

[0081] Please see Figure 2 , Figure 2 This is an exploded structural diagram of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 10 and a battery cell pack 20, the battery cell pack 20 being housed within the housing 10.

[0082] The housing 10 is used to accommodate individual battery cells, and the housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing portion 11 and a second housing portion 12, which overlap each other, and together define a receiving portion for accommodating the battery cell assembly 20. The second housing portion 12 may be a hollow structure with one end open, and the first housing portion 11 may be a plate-like structure, with the first housing portion 11 covering the open side of the second housing portion 12 to form a housing 10 with a receiving portion; alternatively, both the first housing portion 11 and the second housing portion 12 may be hollow structures with one side open, with the open side of the first housing portion 11 covering the open side of the second housing portion 12 to form a housing 10 with a receiving portion. Of course, the first housing portion 11 and the second housing portion 12 can have various shapes, such as cylinders, cuboids, etc.

[0083] As an example, the battery cell pack 20 can be a battery module, which can be housed in the housing by fixing the battery module in the housing.

[0084] As an example, the battery cell pack 20 can also be housed in the housing by directly fixing multiple battery cells to the housing.

[0085] In some embodiments, the housing may be part of the chassis structure of the vehicle 1000. For example, a portion of the housing may be at least a portion of the floor of the vehicle 1000, or a portion of the housing may be at least a portion of the crossbeams and longitudinal beams of the vehicle 1000.

[0086] In some embodiments, the battery device 100 may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0087] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a battery cell pack 20 provided in an embodiment of this application. The battery cell pack 20 includes multiple battery cells 21, which are first connected in series, parallel, or mixed to form the battery cell pack 20, and then the battery cell pack 20 is housed in a casing.

[0088] The following section first describes the battery cell provided in the embodiments of this application. Please refer to... Figures 4 to 8 , Figure 4 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application; Figure 5 for Figure 4 A schematic diagram of the exploded structure of a single battery cell; Figure 6 This is a schematic diagram of the structure of a protective component according to an embodiment of this application; Figure 7 for Figure 6 An enlarged structural diagram of point A in the protective component shown; Figure 8 This is a schematic diagram showing the connection between the protective member and the first wall according to an embodiment of this application.

[0089] Firstly, please refer to Figure 4 , Figure 5 and Figure 6 This application provides a battery cell 21, including a housing 211, an electrode assembly 214, a pressure relief structure 212, and a protective member 213. The housing 211 includes a first wall 2111, the electrode assembly 214 is housed within the housing 211, the pressure relief structure 212 is disposed on the first wall 2111, and the protective member 213 includes a first region 2131 and a second region 2132 disposed around the first region 2131. The first region 2131 is disposed on the side of the pressure relief structure 212 away from the electrode assembly 214. The first region 2131 and the second region 2132 are detachably connected, and the connection strength between the first region 2131 and the first wall 2111 is less than the connection strength between the second region 2132 and the first wall 2111.

[0090] The electrode assembly 214 includes a main body and tabs extending from the main body. Electrode terminals 215 are electrically connected to the tabs to conduct current from the main body. The tabs include a positive tab and a negative tab. Electrode terminals 215 can be directly connected to the tabs or indirectly connected via current collectors. The main body includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the negative and positive electrodes. During the charging and discharging of the battery cell 21, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator prevents short circuits between the positive and negative electrodes while allowing the passage of active ions.

[0091] The first wall 2111 can refer to one of the multiple shell walls of the outer shell 211. For example, the outer shell 211 may include a peripheral wall and a top wall and a bottom wall connected to both ends of the peripheral wall, and the first wall 2111 can be a peripheral wall, a top wall, or a bottom wall, etc. The peripheral wall can be circular, square, or other shapes, etc. For example, when the outer shell 211 is cylindrical, the peripheral wall is circular; when the outer shell 211 is cuboid, the peripheral wall may include multiple side walls, and the first wall 2111 can be one or more of these side walls.

[0092] Optionally, please refer to Figure 8 An insulating patch 2112 is provided between the first wall 2111 and the protective component 213. The insulating patch 2112 is used to achieve insulation isolation between the outer shell 211 and other components in the battery device. The second region 2132 is connected to the insulating patch 2112 to achieve relative fixation between the second region 2132 and the first wall 2111.

[0093] Optionally, the orthographic projection of the protective element 213 in the direction Z perpendicular to the height of the battery cell 21 falls within the orthographic projection range of the first wall 2111 in the direction Z perpendicular to the height of the battery cell 21.

[0094] Optionally, the orthographic projection of the protective element 213 in the direction Z perpendicular to the height of the battery cell 21 is consistent with the orthographic projection range of the first wall 2111 in the direction Z perpendicular to the height of the battery cell 21.

[0095] The pressure relief structure 212 refers to an element or component that is activated to release internal pressure or temperature when the internal pressure or temperature of the battery cell 21 reaches a predetermined threshold. This threshold design varies depending on design requirements. The threshold may depend on one or more materials of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 21. The pressure relief structure 212 can take the form of an explosion-proof valve, explosion-proof disc, gas valve, pressure relief valve, or safety valve, and can specifically employ pressure-sensitive or temperature-sensitive elements or structures. That is, when the internal pressure or temperature of the battery cell 21 reaches the predetermined threshold, the pressure relief structure 212 actuates or a weak area in the pressure relief structure 212 is damaged, thereby forming an opening or channel for releasing internal pressure or temperature.

[0096] Optionally, the second region 2132 is fixedly disposed relative to the first wall 2111 by other components, so that the second region 2132 is relatively fixed to the side of the first wall 2111 away from the electrode assembly 214 and the first region 2131 is relatively fixed to the side of the pressure relief structure 212 away from the electrode assembly 214, thereby maintaining the protective effect of the protective member 213 on the first wall 2111 and the pressure relief structure 212.

[0097] Therefore, a protective element 213 is provided on the side of the first wall 2111 away from the electrode assembly 214 of the battery cell 21 to prevent high-temperature and high-pressure substances discharged from other battery cells 21 from directly splashing onto the first wall 2111 and causing corrosion and melting, thereby reducing the probability of thermal runaway chain reaction in the battery device and improving the reliability of the battery device. Specifically, the protective element 213 is divided into a separable first region 2131 and a second region 2132, and the connection strength between the first region 2131 and the first wall 2111 is less than the connection strength between the second region 2132 and the first wall 2111. This allows the high-pressure gas discharged from the pressure relief structure 212 to impact the first region 2131 and cause the first region 2131 to detach from the first wall 2111 when the battery cell 21 malfunctions, so that the pressure relief structure 212 can release pressure normally, thereby reducing the probability of overpressure and explosion inside the battery cell 21 and improving the safety of the battery cell 21.

[0098] According to some embodiments of this application, the second region 2132 is connected to the first wall 2111.

[0099] Optionally, the first region 2131 is connected to the first wall 2111.

[0100] Optionally, the first region 2131 is connected to the first wall 2111 via the second region 2132.

[0101] Therefore, the second region 2132 is directly connected to the first wall 2111 to improve the connection strength between the second region 2132 and the first wall 2111, thereby reducing the probability that the second region 2132 will detach from the first wall 2111 under the impact of high pressure gas, so that the second region 2132 forms a high temperature resistant protection for the first wall 2111 to improve the safety of the battery cell 21.

[0102] According to some embodiments of this application, the connection strength between the first region 2131 and the second region 2132 is less than the connection strength between the second region 2132 and the first wall 2111.

[0103] Optionally, the connection strength between the second region 2132 and the first region 2131 or the connection strength between the second region 2132 and the first wall 2111 is characterized by peel strength.

[0104] Optionally, the connection strength between the second region 2132 and the first region 2131 or the connection strength between the second region 2132 and the first wall 2111 is characterized by tensile strength.

[0105] Therefore, when the pressure relief structure 212 is activated to relieve pressure and the high-pressure gas impacts the protective component 213, the first region 2131 can separate from the second region 2132 before the first wall 2111, so that while the pressure relief structure 212 meets the pressure relief requirements, the second region 2132 remains connected to the first wall 2111 to form a high-temperature resistant protection, thereby reducing the damage and corrosion of the first wall 2111 by high-temperature and high-pressure substances.

[0106] According to some embodiments of this application, a weak structure 2133 is provided between the first region 2131 and the second region 2132 so that the first region 2131 and the second region 2132 can be detachably connected.

[0107] Optionally, the thickness of the weak structure 2133 is less than the thickness of the first region 2131, and the thickness of the weak structure 2133 is less than the thickness of the second region 2132.

[0108] Optionally, the material strength of the weak structure 2133 is less than the material strength of the first region 2131, and the material strength of the weak structure 2133 is less than the material strength of the second region 2132.

[0109] Therefore, when the pressure relief structure 212 needs to release pressure, the high-pressure gas impacts the protective component 213. At this time, the weak structure 2133 can be damaged before the first region 2131 and the second region 2132, for example, by cracking, so that the first region 2131 and the second region 2132 can be separated. After the first region 2131 is separated, the pressure relief structure 212 is exposed to complete the pressure relief.

[0110] According to some embodiments of this application, the geometric center of the weak structure 2133 overlaps with the geometric center of the pressure relief structure 212.

[0111] Optionally, the shape of the weak structure 2133 is the same as the shape of the pressure relief structure 212. Here, "the shape of the weak structure 2133 is the same as the shape of the pressure relief structure 212" means that the geometric shapes of the weak structure 2133 and the pressure relief structure 212 are the same or approximately the same. When the shape of the weak structure 2133 is the same as the shape of the pressure relief structure 212, the dimensions of the weak structure 2133 are also equal to or proportional to the dimensions of the pressure relief structure 212. Due to factors such as processing technology, there may be errors in the processing of the weak structure 2133. In this case, the shape of the weak structure 2133 and the shape of the pressure relief structure 212 can be approximately the same, but the dimensions of the weak structure 2133 and the dimensions of the pressure relief structure 212 may not be exactly the same or not completely proportional.

[0112] Optionally, the shape of the weak structure 2133 is differentiated from the shape of the pressure relief structure 212. For an example, please refer to... Figure 8 A connector, such as a screw, is provided near the pressure relief structure 212 to allow the pressure relief structure 212 or the first wall 2111 to be detachably connected to other components of the housing 211. The shape of the weak structure 2133 is different from that of the pressure relief structure 212 so that the connector is exposed to meet the needs of subsequent disassembly and repair.

[0113] Alternatively, the weak structure 2133 includes at least one straight edge, with the stress distribution at the endpoint of the straight edge being more concentrated, so that the weak structure 2133 is more prone to cracking.

[0114] Alternatively, the weak structure 2133 may include at least one curved edge, with a more uniform stress distribution along the curved edge, to improve the controllability of the crack trajectory of the weak structure 2133.

[0115] This improves the alignment between the weak structure 2133 and the pressure relief structure 212. The gap formed after the first region 2131 separates from the second region 2132 can more accurately expose the pressure relief structure 212, shorten the release path of high-pressure gas, and reduce the heat accumulation inside the battery cell 21.

[0116] According to some embodiments of this application, on a plane parallel to the first wall 2111, the maximum distance between the boundary line of the weak structure 2133 and the boundary line of the pressure relief structure 212 is less than 3 mm.

[0117] For example, the maximum distance between the boundary line of the weak structure 2133 and the boundary line of the pressure relief structure 212 is one of 2.8mm, 2.6mm, 2.4mm, 2.2mm, 2mm, 1.8mm, 1.6mm, 1.4mm, and 1.2mm.

[0118] Optionally, the maximum distance between the boundary line of the weak structure 2133 and the boundary line of the pressure relief structure 212 is less than 1 mm. For example, the maximum distance between the boundary line of the weak structure 2133 and the boundary line of the pressure relief structure 212 is one of 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, and 0.05 mm.

[0119] Therefore, by limiting the range of the weak structure 2133 to adjust the range of the void formed after the first region 2131 is detached, it helps to release the high-pressure gas after the pressure relief structure 212 is opened, and reduces the exposed area of ​​the first wall 2111 to reduce the probability of high-temperature and high-pressure substances splashing through the void onto the first wall 2111 and causing corrosion and melting.

[0120] According to some embodiments of this application, please refer to Figure 7 The weak structure 2133 includes multiple connecting parts 21331 and a hollow part 21332 disposed between two adjacent connecting parts 21331. The multiple connecting parts 21331 are connected end to end so that the first region 2131 and the second region 2132 can be detachably connected.

[0121] Optionally, the cutout portion 21332 is a structure that always connects the side of the protective member 213 near the electrode assembly 214 and the side away from the electrode assembly 214, such as a through hole; or, the cutout portion 21332 is a structure that can be opened under the impact of high-pressure gas to achieve communication between the side of the protective member 213 near the electrode assembly 214 and the side away from the electrode assembly 214, such as a serrated groove. When the pressure relief structure 212 is opened, the tips of the serrations are blown open and a triangular window is exposed to achieve pressure relief.

[0122] Therefore, the weak structure 2133 is in the form of a tear line. On the one hand, the hollow part 21332 can meet the small pressure relief requirements of the pressure relief structure 212 when the first region 2131 and the second region 2132 are connected. On the other hand, after the tear line is broken by local impact, it can break more easily along the pre-set trace where the beginning and end are connected, so that the first region 2131 can quickly separate from the second region 2132 to complete the pressure relief.

[0123] According to some embodiments of this application, along the extension direction of the weak structure 2133, the length of the hollow portion 21332 is greater than the length of the connecting portion 21331.

[0124] Optionally, along the extension direction of the weak structure 2133, the length of the hollow portion 21332 is greater than the length of the two adjacent connecting portions 21331.

[0125] Alternatively, along the extension direction of the weak structure 2133, the length of the shortest hollow portion 21332 is greater than the length of the longest connecting portion 21331.

[0126] This reduces the tearing force of the weak structure 2133, making it more susceptible to cracking under the impact of high-pressure gas, thus improving the safety of the battery cell 21.

[0127] According to some embodiments of this application, the lengths of each connecting portion 21331 are the same along the extension direction of the weak structure 2133.

[0128] As a result, the stress distribution of each connection 21331 in the weak structure 2133 is more uniform, so that the cracking trajectory of the weak structure 2133 is closer to the preset mark.

[0129] According to some embodiments of this application, at least two connecting portions 21331 are provided with different lengths along the extension direction of the weak structure 2133.

[0130] Therefore, the shorter connection part 21331 can crack earlier, reducing the cracking threshold of the weak structure 2133, so that the pressure relief structure 212 can release pressure smoothly earlier, improving the safety of the battery cell 21.

[0131] According to some embodiments of this application, the connection between the second region 2132 and the first wall 2111 includes at least one of bonding, welding, riveting, and fastener connection.

[0132] Optionally, the second region 2132 is bonded to the first wall 2111 by an adhesive.

[0133] Optionally, an insulating patch 2112 is provided between the second region 2132 and the first wall 2111. The surface of the insulating patch 2112 is dissolved by a solvent to mix the material between the surface of the insulating patch 2112 and the surface of the protective component 213. When the solvent evaporates, an adhesive joint is formed to achieve relative fixation between the second region 2132 and the first wall 2111.

[0134] Optionally, the fasteners include threaded parts and connecting components such as snap fasteners. The fasteners can be used alone or in combination.

[0135] This achieves relative fixation between the second region 2132 and the first wall 2111, and between the first region 2131 and the pressure relief structure 212.

[0136] According to some embodiments of this application, the battery cell 21 further includes an electrode terminal 215, which is at least partially disposed on the first wall 2111 and electrically connected to the electrode assembly 214. A clearance hole 21321 is provided in the second region 2132 to allow the power terminal 215 to pass through.

[0137] Optionally, the electrode terminal 215 is directly connected to the tab of the electrode assembly 214, or the electrode terminal 215 is indirectly connected to the tab through a current collector.

[0138] Optionally, the size of the clearance hole 21321 is the same as the size of the electrode terminal 215, so that the second region 2132 provides better protection for the first wall 2111.

[0139] Optionally, the clearance hole 21321 is larger than the electrode terminal 215 to facilitate the assembly of the second region 2132 to the electrode terminal 215.

[0140] Therefore, the clearance hole 21321 can be used to assist in the assembly and positioning between the protective component 213 and the first wall 2111, thereby reducing the assembly difficulty between the protective component 213 and the first wall 2111.

[0141] According to some embodiments of this application, the thickness of the protective member 213 is less than the length of the electrode terminal 215 extending out of the first wall 2111, or the thickness of the protective member 213 is equal to the length of the electrode terminal 215 extending out of the first wall 2111.

[0142] Specifically, the length of the electrode terminal 215 extending beyond the first wall 2111 refers to the length of the portion of the electrode terminal 215 that is connected to the electrode assembly 214 and extends beyond the first wall 2111 in the height direction Z of the battery cell 21. For example, the electrode terminal 215 includes a first boss, and the thickness of the protective member 213 does not exceed the length of the first boss extending beyond the first wall 2111.

[0143] Therefore, the protective component 213 can be compatible with the portion of the electrode terminal 215 that extends out of the first wall 2111, thereby reducing the space occupied by the protective component 213 in the height direction Z of the battery cell 21 and improving the integration of the battery cell 21.

[0144] According to some embodiments of this application, the material of the protective element 213 includes at least one of mica, aluminum silicate fiber, hydroxyapatite, polyimide, and polyethylene.

[0145] Optionally, the protective component 213 is made of muscovite as raw material, which is broken into pulp by thermochemical or hydraulic stripping and papermaking, and then processed into single sheets or continuous rolls.

[0146] Therefore, the protective component 213 can withstand high-temperature and high-pressure substances below 1500°C without being melted through, thereby preventing the high-temperature and high-pressure substances from penetrating the protective component 213 and directly contacting the first wall 2111 to trigger a subsequent thermal runaway chain reaction.

[0147] According to some embodiments of this application, the thickness of the protective element 213 is greater than or equal to 0.01 mm.

[0148] Optionally, the thickness of the protective component 213 is less than or equal to 3 mm, so as to reduce the space occupied by the protective component 213 in the height direction Z of the battery cell 21 and reduce the space encroachment of the protective component 213 on other components in the battery cell 21.

[0149] For example, the thickness of the protective element 213 is one of 0.05mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, and 3mm.

[0150] Therefore, the protective component 213 has sufficient high temperature resistance to resist corrosion from high temperature and high pressure substances, thereby reducing the probability that high temperature and high pressure substances will penetrate the protective component 213 and come into direct contact with the first wall 2111.

[0151] According to some embodiments of this application, the thickness of the protective element 213 is greater than or equal to 0.1 mm.

[0152] Optionally, the thickness of the protective component 213 is less than or equal to 0.5 mm, so as to further reduce the space occupied by the protective component 213 in the height direction Z of the battery cell 21, making it easier to install and modify the protective component 213 on the existing battery cell 21, and expanding the application range of the protective component 213.

[0153] This further enhances the high-temperature resistance of the protective component 213, reduces the heat conduction from high-temperature and high-pressure substances to the first wall 2111 through the protective component 213, and reduces the probability of thermal runaway of the internal electrode assembly 214 caused by local heat accumulation in the first wall 2111.

[0154] Secondly, embodiments of this application provide a battery device, which includes a housing and at least one battery cell 21 as provided in any embodiment of the first aspect, the battery cell 21 being housed within the housing. Because each battery cell 21 has a protective element 213 with a higher melting point on the side of the first wall 2111 facing away from the electrode assembly 214, which has a lower melting point, the probability of thermal runaway chain reaction occurring inside the battery device is reduced, thereby improving the safety and reliability of the battery device.

[0155] Thirdly, embodiments of this application provide an electrical device configured to receive electrical energy provided by a battery device as provided in any embodiment of the second aspect.

[0156] Please see Figures 4 to 8 This application provides a battery cell 21, which includes a housing 211. The housing 211 includes a first wall 2111, the first wall 2111 having a pressure relief structure 212, and an insulating patch 2112 on the side of the first wall 2111 facing away from the electrode assembly 214. The battery cell 21 also includes a protective member 213, which is disposed on the side of the insulating patch 2112 facing away from the electrode assembly 214. The protective member 213 includes a first region 2131 and a second region 2132. Along the height direction Z of the battery cell 21, the first region 2131 is disposed above the pressure relief structure 212 and the second region 2132 is disposed above the insulating patch 2112.

[0157] When the electrode assembly 214 malfunctions, the pressure relief structure 212 opens and releases high-pressure gas. The high-pressure gas is released through the hollow portion 21332 of the weak structure 2133 to reduce heat accumulation inside the battery cell 21. When the malfunction of the electrode assembly 214 intensifies and a large amount of high-pressure gas is released, the high-pressure gas impacts the protective component 213. Under the impact of the high-pressure gas, the weak structure 2133 tears, and the first region 2131 separates from the second region 2132 to form a window. The high-pressure gas can be released quickly through the window to reduce the probability of further explosion of the battery cell 21.

[0158] When other battery cells 21 in the battery device explode and release high-pressure and high-temperature substances, such as electrode material fragments, metal fragments or electrolyte, the splashed high-temperature and high-pressure substances will preferentially contact the protective component 213 to reduce the conduction of heat to the insulating patch 2112 and the pressure relief structure 212, thereby reducing the accumulation of heat inside the battery cell 21 and reducing the probability of thermal runaway chain reaction.

[0159] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The outer shell, including the first wall; Electrode assembly, housed within the housing; A pressure relief structure is provided on the first wall; The protective element includes a first region and a second region disposed around the first region, the first region being disposed on the side of the pressure relief structure opposite to the electrode assembly; The first region and the second region are detachably connected, and the connection strength between the first region and the first wall is less than the connection strength between the second region and the first wall.

2. The battery cell according to claim 1, characterized in that, The second region is connected to the first wall, and the first region is connected to the first wall through the second region.

3. The battery cell according to claim 2, characterized in that, The connection strength between the first region and the second region is less than the connection strength between the second region and the first wall.

4. The battery cell according to claim 3, characterized in that, A weak structure is provided between the first region and the second region to allow the first region and the second region to be separably connected.

5. The battery cell according to claim 4, characterized in that, The shape of the weak structure is the same as that of the pressure relief structure, and their geometric centers overlap.

6. The battery cell according to claim 5, characterized in that, On a plane parallel to the first wall, the maximum distance between the boundary line of the weak structure and the boundary line of the pressure relief structure is less than 3 mm.

7. The battery cell according to claim 4, characterized in that, The weak structure includes multiple connecting parts and a hollowed-out part disposed between two adjacent connecting parts, and the multiple connecting parts are connected end to end so that the first region and the second region can be detachably connected.

8. The battery cell according to claim 7, characterized in that, Along the extension direction of the weak structure, the length of the hollow portion is greater than the length of the connecting portion.

9. The battery cell according to claim 8, characterized in that, Along the extension direction of the weak structure, the lengths of all the connecting portions are the same, or, along the extension direction of the weak structure, the lengths of at least two of the connecting portions are set differently.

10. The battery cell according to claim 2, characterized in that, The connection between the second region and the first wall includes at least one of bonding, welding, riveting, and fastener connection.

11. The battery cell according to claim 10, characterized in that, The battery cell also includes an electrode terminal, which is at least partially disposed on the first wall and electrically connected to the electrode assembly. The second region has a clearance hole for the electrode terminal to pass through.

12. The battery cell according to claim 11, characterized in that, The thickness of the protective element is less than the length of the electrode terminal extending out of the first wall, or the thickness of the protective element is equal to the length of the electrode terminal extending out of the first wall.

13. The battery cell according to claim 1, characterized in that, The material of the protective component includes one of mica, aluminum silicate fiber, hydroxyapatite, polyimide, and polyethylene.

14. The battery cell according to claim 13, characterized in that, The thickness of the protective component is greater than or equal to 0.01 mm and less than or equal to 3 mm.

15. The battery cell according to claim 14, characterized in that, The thickness of the protective component is greater than or equal to 0.1 mm and less than or equal to 0.5 mm.

16. A battery device, characterized in that, It includes a housing and at least one battery cell as described in any one of claims 1 to 15, wherein the battery cell is housed within the housing.

17. An electrical device, characterized in that, The electrical device is configured to receive electrical energy supplied from the battery device of claim 16.

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