Battery monomer and device, power utilization device, energy storage device and system, and charging network

Abstract

The utility model provides a battery monomer and device, a power utilization device, an energy storage device and system and a charging network, and belongs to the technical field of batteries, the battery monomer comprises an electrode assembly, an insulating film, an end cover and a shell, the insulating film sleeves the outer surface of the electrode assembly, the shell forms a containing cavity with an opening, the containing cavity is used for containing the electrode assembly and the insulating film, and the end cover is arranged in the containing cavity. The shell comprises a bottom wall right opposite to the opening, and a pressure relief mechanism is arranged on the bottom wall. The end cover covers the opening of the shell so as to seal the accommodating cavity, and the end cover is provided with an electrode terminal connected with the electrode assembly; wherein the insulating film is provided with a structure weak part, and the orthographic projection of the structure weak part on the bottom wall is at least partially overlapped with the pressure relief mechanism. According to the embodiment of the invention, the service life of the device or system where the battery monomer is located can be prolonged.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to sustainable social development. Rechargeable batteries, with their ability to store and release energy as needed, are widely used in various electrical devices and energy storage systems, playing a crucial role in promoting energy transformation and sustainable development. Battery technology is a crucial factor in the development of the new energy industry.

[0003] When a battery experiences thermal runaway, a large amount of gas will be generated in a short period of time. If the gas cannot be discharged in time, serious consequences may occur. Utility Model Content

[0004] The present application aims to solve at least one of the technical problems in the background art. To this end, one purpose of the present application is to provide a battery cell and device, an electrical device, an energy storage device and system, and a charging network to increase the service life of the device or system in which the battery cell is located.

[0005] An embodiment of the first aspect of the present application provides a battery cell comprising an end cap, a housing, an electrode assembly, and an insulating film. The insulating film is sleeved over the outer surface of the electrode assembly, the housing forms a receiving cavity with an opening for accommodating the electrode assembly and the insulating film, the housing including a bottom wall directly opposite the opening, the bottom wall being provided with a pressure relief mechanism; the end cap is engaged with the opening of the housing to seal the receiving cavity, and the end cap is provided with an electrode terminal connected to the electrode assembly; the insulating film is provided with a structurally weak portion, the orthographic projection of the structurally weak portion on the bottom wall at least partially overlapping with the pressure relief mechanism.

[0006] In the technical solution of the embodiment of the present application, on the one hand, the gas can be guided along the weak part of the structure to break through the obstruction of the insulating film, which is conducive to achieving directional pressure relief and improving the reliability of pressure relief of the battery cell. On the other hand, the pressure relief mechanism is far away from the electrode terminal, which reduces the adverse effects of the ejected gas and electrolyte on the electrode terminal and other components connected to the electrode terminal, thereby improving the service life of the device or system in which the battery cell is located.

[0007] In some embodiments, the structurally weak portion comprises a groove recessed along the thickness of the insulating film. By employing a groove structure design on the insulating film, the insulating film's isolation effect is maintained while simultaneously reducing its structural strength, facilitating the rapid formation of an exhaust outlet in the event of thermal runaway, thereby achieving reliable, directional exhaust.

[0008] In some embodiments, the groove portion is an annular groove that encloses and forms a first closed area. The boundary of the first closed area is the outer edge of the annular groove that is away from the center of the first closed area. The annular groove is located within the first closed area. By providing the annular groove and forming the first closed area, the breakthrough area of ​​the gas through the insulating film can be more accurately defined, thereby better guiding the gas flow and achieving reliable and accurate directional pressure relief.

[0009] In some embodiments, the orthographic projection of the first closed area on the bottom wall completely falls within the range of the pressure relief mechanism. Enabling the orthographic projection of the first closed area on the bottom wall completely within the range of the pressure relief mechanism can better guide gas to the pressure relief mechanism, thereby achieving more efficient directional pressure relief.

[0010] In some embodiments, the structurally weak portion includes a hollow portion extending through the thickness of the insulating film. The hollow portion can significantly weaken the strength of the insulating film, reducing the resistance to gas breakthrough, thereby better guiding the gas to the pressure relief mechanism for exhaust more quickly, thereby improving the reliability of pressure relief.

[0011] In some embodiments, the hollow portion includes a plurality of hollow grooves, which are sequentially spaced along the periphery of the second closed area. The boundary of the second closed area is formed by sequentially connecting the outer edges of the plurality of hollow grooves away from the center of the second closed area, and the plurality of hollow grooves are located within the second closed area. By providing a plurality of spaced hollow grooves to form the second closed area, the breakthrough area of ​​the gas through the insulating film can be more accurately defined, thereby better guiding the gas flow and achieving reliable and accurate directional pressure relief.

[0012] In some embodiments, the orthographic projection of the second closed area on the bottom wall completely falls within the range of the pressure relief mechanism. Enabling the orthographic projection of the second closed area on the bottom wall completely within the range of the pressure relief mechanism can better guide gas to the pressure relief mechanism, thereby more efficiently achieving directional pressure relief.

[0013] In some embodiments, the outline of the second closed area is a rectangle, the length of the long side of the outline of the second closed area is A, the cumulative overlapping length of the hollow portion and one of the long sides of the outline of the second closed area is a, and the following conditions are satisfied: a / A ≥ 50%. In some embodiments, the outline of the second closed area is a rectangle, the length of the short side of the outline of the second closed area is B, the cumulative overlapping length of the hollow portion and one of the short sides of the outline of the second closed area is b, and the following conditions are satisfied: b / B ≥ 40%. By limiting the proportion of the overlapping length of the hollow portion and the second closed area on different sides, the reliability of the gas breaking through the insulating film barrier can be further improved, and the gas flow direction can be accurately guided to achieve more precise directional pressure relief.

[0014] In some embodiments, the hollowed-out groove is rectangular, with its long side coinciding with the outline of the second closed area. By defining the shape and arrangement of the hollowed-out groove, the area where gas breaks through the insulating film can be further limited, thereby more accurately directing the gas flow and improving the reliability of directional pressure relief.

[0015] In some embodiments, the hollow groove includes a first groove and a second groove. The first groove extends parallel to the long side of the second closed region's outline, and the second groove extends parallel to the short side of the second closed region's outline. The width of the first groove is b1, and the width of the second groove is b2, satisfying the following: b1 ≥ b2. Because the long side of the second closed region's outline is larger, setting the width of the first groove extending in that direction to be greater than or equal to the width of the second groove can provide more favorable conditions for gas to break through the insulating film smoothly along the second closed region, thereby improving the reliability of directional exhaust.

[0016] In some embodiments, there are multiple first grooves, each having the same width. In some embodiments, there are multiple second grooves, each having the same width. Setting the widths of multiple first grooves extending in the same direction to be the same, or setting the widths of multiple second grooves to be the same, can improve the uniformity of gas penetration through the insulating film.

[0017] In some embodiments, the width b1 of the first groove satisfies the following conditions: 0.5 mm ≤ b1 ≤ 4 mm. In some embodiments, the width b2 of the second groove satisfies the following conditions: 0.5 mm ≤ b2 ≤ 4 mm. By selecting an appropriate width, the isolation effect of the insulating film and the reliability of gas penetration through the insulating film can be balanced, thereby improving the overall performance of the battery cell.

[0018] In some embodiments, the pressure relief mechanism includes notches on the bottom wall surface. Introducing notches on the bottom wall facilitates directional pressure relief through the pressure relief mechanism in the event of thermal runaway, thereby helping to improve the reliability of pressure relief of the battery cells.

[0019] In some embodiments, the bottom wall includes a first surface facing the electrode assembly and a second surface facing away from the electrode assembly; wherein the notches include two first notches spaced apart on the first surface, two second notches spaced apart on the second surface, and a third notch connecting the two second notches, respectively, with the first notches extending in a direction that intersects the second notches. Providing notches on both sides of the bottom wall balances the structural strength of the bottom wall, and providing the third notch between the two second notches facilitates forming a split-type exhaust structure, thereby improving pressure relief and exhaust efficiency.

[0020] In some embodiments, the length of the first notch is less than the length of the second notch. In some embodiments, the depth of the first notch is less than the depth of at least one of the second and third notches. By employing differentiated designs for the length or depth of the notches, the pressure relief mechanism first breaks away from the notch on the second surface and then folds around the first notch to form an outlet for exhaust, reducing the possibility of fragmentation due to gas impact.

[0021] In some embodiments, the capacity of the battery cell is greater than or equal to 360Ah. Providing a structurally weak portion in the insulating film as described in the embodiments of this application can improve the reliability of directional pressure relief, thereby better meeting the pressure relief requirements of large-capacity battery cells and improving the overall performance of the battery cell.

[0022] An embodiment of a second aspect of the present application provides a battery device, which includes the battery cell in the above embodiment.

[0023] An embodiment of the third aspect of the present application provides an electrical device, which includes the battery device in the above embodiment, and the battery device is used to provide electrical energy.

[0024] An embodiment of the fourth aspect of the present application provides an energy storage device, which includes a plurality of battery cells or battery devices in the above embodiments, and the battery cells or battery devices are used to store or provide electrical energy.

[0025] An embodiment of the fifth aspect of the present application provides an energy storage system, which includes a power conversion device and the energy storage device in the above embodiment, and the power conversion device is used to electrically connect the power generation device and the energy storage device.

[0026] An embodiment of the sixth aspect of the present application provides a charging network, which includes a charging pile and the energy storage device in the above embodiment or the energy storage system in the above embodiment, and the energy storage device or the energy storage system is used to provide electrical energy for the charging pile.

[0027] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0029] Figure 1 A schematic diagram of the exploded structure of a battery device provided in some embodiments of the present application;

[0030] Figure 2 A schematic diagram of the structure of an energy storage system provided in some embodiments of the present application;

[0031] Figure 3 A schematic diagram of the structure of a charging network provided in some embodiments of the present application;

[0032] Figure 4 A schematic diagram of the exploded structure of a battery cell provided in some embodiments of the present application;

[0033] Figure 5 A schematic structural diagram of the relative positions of the insulating film and the pressure relief mechanism of the bottom wall provided in some embodiments of the present application;

[0034] Figure 6 A schematic structural diagram of a first insulating film provided in some embodiments of the present application;

[0035] Figure 7 A schematic structural diagram of a second insulating film provided in some embodiments of the present application;

[0036] Figure 8 for Figure 7 A schematic diagram of the partially enlarged structure of part C in the middle;

[0037] Figure 9 for Figure 4 Bottom view along the D direction.

[0038] Description of reference numerals:

[0039] 100. Battery device; 200. Energy storage device; 300. Power conversion device; 400. Power generation equipment; 500. Charging pile; 600. Connector; 10. Housing; 11. First part; 12. Second part; 20. Battery cell; 21. End cover; 21a. Electrode terminal; 22. Housing; 221. Bottom wall; 222. Pressure relief mechanism; 2221. First notch; 2222. Second notch; 2223. Third notch; 23. Electrode assembly; 23a. Tab; 24. Insulating film; 241. Groove portion; 242. First closed area; 243. Hollow portion; 2431. Hollow groove; 2432. First groove; 2433. Second groove; 244. Second closed area; 25. Support member; 26. Structural weak portion. DETAILED DESCRIPTION

[0040] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0042] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0043] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0044] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0045] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0046] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0047] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0048] Currently, market developments indicate that rechargeable batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in various electronic devices, including electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As the application areas of rechargeable batteries continue to expand, market demand is also growing.

[0049] Battery cells generate large amounts of gas when experiencing thermal runaway, which can have serious consequences if not discharged in a timely manner. A pressure relief mechanism is usually installed on the battery casing. When the internal pressure of a battery cell rapidly increases due to the generation of a large amount of gas, the gas can break through the pressure relief mechanism and be discharged to the outside of the casing, thereby reducing the internal pressure of the battery cell. However, components inside the battery cell may hinder the flow of gas to the pressure relief mechanism. For example, the pressure relief mechanism is installed on the bottom wall of the casing. After the gas is generated inside the electrode assembly, it needs to pass through components such as the insulating film to reach the location of the pressure relief mechanism. The obstruction of the insulating film may prevent the gas from being discharged smoothly and directionally from the pressure relief mechanism.

[0050] In some embodiments, the energy storage device or energy storage system includes multiple connected battery cells, and the pressure relief mechanism of a single battery cell is located on the same side as the electrode terminal. The gas and electrolyte ejected from the pressure relief mechanism may impact the electrode terminal and other battery cells connected to the electrode terminal, thereby potentially having an adverse effect on the electrode terminal and other battery cells connected to the electrode terminal, thereby reducing the service life of the energy storage device or energy storage system.

[0051] In order to solve the above problems, an embodiment of the first aspect of the present application provides a battery cell, which includes an electrode assembly, an insulating film, an end cover and a shell. The insulating film is sleeved on the outer surface of the electrode assembly, and the shell forms a accommodating cavity with an opening, which is used to accommodate the electrode assembly and the insulating film. The shell includes a bottom wall opposite to the opening, and a pressure relief mechanism is provided on the bottom wall; the end cover covers the opening of the shell to close the accommodating cavity, and the end cover is provided with an electrode terminal connected to the electrode assembly; wherein the insulating film is provided with a structurally weak portion, and the positive projection of the structurally weak portion on the bottom wall at least partially overlaps with the pressure relief mechanism.

[0052] On the one hand, a structurally weak portion is provided on the insulating film in the path where the gas flows to the pressure relief mechanism, so that the gas generated by thermal runaway can smoothly break through the obstacles and reach the pressure relief mechanism, thereby realizing directional exhaust and improving the reliability of battery cell pressure relief. On the other hand, the pressure relief mechanism is far away from the electrode terminal, which reduces the adverse effects of the ejected gas and electrolyte on the electrode terminal and other components connected to the electrode terminal, thereby improving the service life of the device or system in which the battery cell is located.

[0053] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices or energy storage devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to construct such electrical devices or energy storage devices, thereby improving the reliability of the battery cell pressure relief.

[0054] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0055] For the convenience of description, the following embodiments are described by taking a battery device according to an embodiment of the present application as an example.

[0056] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the exploded structure of a battery device provided in some embodiments of the present application. The battery device 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20, and the housing 10 can have a variety of structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cell 20. The second portion 12 can be a hollow structure with one end open, and the first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. The first portion 11 and the second portion 12 can also be hollow structures with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have a variety of shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0057] In the battery device 100, there may be multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery unit 20 may be housed within the housing 10. Alternatively, the battery device 100 may comprise multiple battery cells 20 connected in series, in parallel, or in a hybrid connection to form a battery module, which is then further connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 10. The battery device 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0058] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0059] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of an energy storage system provided in some embodiments of the present application. This embodiment of the present application provides an energy storage device 200, which includes one or more battery clusters to increase the voltage and capacity of the energy storage device 200. The battery cluster may include multiple battery devices 100, which are connected in series via a busbar to increase the voltage of the energy storage device 200. When the energy storage device 200 includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device 200. The energy storage device 200 can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. The energy storage device 200 can store electrical energy as needed and output it at the appropriate time. For example, the energy storage device 200 can store electrical energy during low-demand periods and provide electrical energy to relevant users or electrical equipment during peak periods. The energy storage system provided in the embodiments of the present application can be any power system that requires the energy storage device 200. In some embodiments, the energy storage device 200 is an energy storage container or an energy storage cabinet.

[0060] In some embodiments, the energy storage device 200 may include a cabinet and one or more battery clusters, where the battery clusters are housed in the cabinet.

[0061] In some embodiments, the energy storage device 200 may include modules such as a thermal management module, a main control module, a master control module, a power distribution module, and a fire protection module.

[0062] As an example, the thermal management module may include a liquid cooling unit that provides cooling liquid for regulating the temperature of the battery cells 20 to each battery device 100 through a pipeline.

[0063] For example, the master control module (MCM) can serve as the battery management unit (BMU) of a battery cluster, monitoring and managing the cluster. The MCM can monitor information such as the battery cluster's current, voltage, power, and temperature. For example, it can control the battery cluster's charge and discharge current and voltage. The MCM includes modules such as the slave battery management unit (SBMU) and the fusion switch.

[0064] As an example, the master control module can serve as the battery management unit of the energy storage device 200, used to monitor and manage the energy storage device 200. The master control module can monitor information such as the current, voltage, power, state of charge, or temperature of the energy storage device 200. For example, it can control the charge and discharge current and voltage of the energy storage device 200. As an example, the master control module includes modules such as an insulation monitoring module (IMM), a master battery management unit (MBMU), an Ethernet (ETH), and a fiber optic conversion module.

[0065] As an example, the fire protection system includes a control panel, detectors, alarm devices, etc., which are used to detect, alarm or extinguish fires in the energy storage system.

[0066] As an example, the power distribution device may be used to distribute power to the power modules of the energy storage device 200 .

[0067] In some embodiments, the energy storage system may include one or more energy storage devices 200 and a power converter 300 (Power Converter System, PCS for short). The power converter 300 is used to connect between the power generation equipment 400 and the energy storage device 200. The power generation equipment 400 is used to generate electrical energy. The electrical energy generated by the power generation equipment 400 can be stored in the energy storage device 200 through the power converter 300, and the electrical energy stored in the energy storage device 200 can be released to the power generation equipment 400 through the power converter 300. As an example, the power generation equipment 400 can specifically be a power grid, a solar panel, a hydroelectric power generation equipment, a thermal power generation equipment, a wind power generation equipment, etc. The specific type of the power generation equipment 400 is not limited in this application.

[0068] Please refer to Figure 3 , Figure 3Schematic diagram of the structure of a charging network provided in some embodiments of the present application. Embodiments of the present application provide a charging network, including a charging pile 500 and an energy storage device 200. The charging pile 500 is electrically connected to the energy storage device 200, and the energy storage device 200 is used to provide electrical energy to the charging pile 500. The charging pile 500 is electrically connected to the battery device 100 in the energy storage device 200 via a cable, and the battery device 100 can provide its stored electrical energy to the charging pile 500. The charging pile 500 has one or more connectors 600, which are used to connect to an electrical device (such as a vehicle) so that energy can be replenished to the electrical device.

[0069] The energy storage device 200 may be located inside the charging pile 500 (eg, an integrated storage and charging device), or may be located outside the charging pile 500 .

[0070] Please refer to Figure 4 , Figure 4 The following is a schematic diagram of the decomposition structure of a battery cell provided in some embodiments of the present application. A battery cell 20 is the smallest unit that makes up a battery. Figure 4 The battery cell 20 includes an end cap 21, a shell 22, an electrode assembly 23 and other functional components.

[0071] The end cap 21 is a component that covers the opening of the housing 22 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 21 can be adapted to the shape of the housing 22 to fit the housing 22. Optionally, the end cap 21 can be made of a material with a certain degree of hardness and strength (such as an aluminum alloy). This prevents the end cap 21 from deforming under compression or collision, thereby enhancing the structural strength and safety of the battery cell 20. The end cap 21 can be provided with functional components such as electrode terminals 21a. The electrode terminals 21a can be used to electrically connect to the electrode assembly 23 to transmit or receive electrical energy from the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism to release internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cap 21 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic, and this is not particularly limited in the present embodiments. In some embodiments, an insulating member may be provided inside the end cap 21 to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. For example, the insulating member may be made of plastic, rubber, or the like.

[0072] The housing 22 is a component that cooperates with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and end cap 21 can be separate components. An opening can be provided in the housing 22, and the end cap 21 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and housing 22 can be integrated. Specifically, the end cap 21 and housing 22 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 22 needs to be enclosed, the end cap 21 is placed over the housing 22. The housing 22 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, or a hexagonal prism. Specifically, the shape of the housing 22 can be determined based on the specific shape and size of the electrode assembly 23. The housing 22 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0073] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 22. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute a tab 23a. The positive and negative electrode tabs may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs 23a connect the electrode terminals to form a current loop.

[0074] The present embodiment provides a battery cell 20, which includes an end cap 21, a housing 22, an electrode assembly 23, and an insulating film 24. The insulating film 24 is sleeved over the outer surface of the electrode assembly 23. The housing 22 forms a receiving cavity with an opening for accommodating the electrode assembly 23 and the insulating film 24. The housing 22 includes a bottom wall 221 facing the opening, and a pressure relief mechanism 222 is provided on the bottom wall 221. The end cap 21 covers the opening of the housing 22 to seal the receiving cavity. The end cap 21 is provided with an electrode terminal 21a connected to the electrode assembly 23. The insulating film 24 has a structurally weakened portion 26, the orthographic projection of which on the bottom wall 221 at least partially overlaps with the pressure relief mechanism 222.

[0075] like Figure 4 and Figure 5As shown, the insulating film 24 may be a Mylar film made of PET (Polyethylene Terephthalate). The insulating film 24 is fixedly mounted on the outer surface of the electrode assembly 23 to ensure insulation between the electrode assembly 23 and the housing 22 after insertion. The insulating film 24 may be fixedly connected to the electrode assembly 23 by means of clipping, bonding, hot-melt connection, or other methods, which are not limited in this application.

[0076] In some embodiments, the battery cell 20 further includes a support member 25. The support member 25 is a component disposed within the housing cavity for supporting the electrode assembly 23. The support member 25 must possess a certain strength and rigidity to meet support requirements. The support member 25 can elevate the electrode assembly 23 to avoid the rounded corners formed at the bottom edge of the housing 22 during stamping, thereby preventing the electrode assembly 23 from being pressed against the rounded corners at the bottom of the housing 22.

[0077] In some embodiments, the support member 25 may be a flat plate structure, and its material may be a metal material, such as copper, aluminum, or corresponding alloys, or a non-metallic insulating material, such as PP (Polypropylene), PI (Polyimide), or PET.

[0078] The bottom wall 221 is the wall of the shell 22 facing the opening. In some embodiments, the end cover 21 serves as a cover plate to cover the opening of the shell 22 to close the accommodating cavity, and the bottom wall 221 serves as a bottom plate located at the bottom of the electrode assembly 23. The electrode terminal 21a provided on the end cover 21 and connected to the electrode assembly 23 may include a positive terminal and a negative terminal.

[0079] The pressure relief mechanism 222 is designed to rupture when the internal pressure of the battery cell 20 reaches a set threshold, allowing the gas inside the battery cell 20 to escape. The pressure relief mechanism 222 is located on the bottom wall 221, directly opposite the opening. This prevents ejected gas and electrolyte from reaching the electrode terminals 21a or other adjacent battery cells, achieving thermal and electrical separation, reducing the risk of gas spreading to surrounding battery cells, and lowering the probability of accidents in the battery device 100 under extreme conditions.

[0080] In some embodiments, the pressure relief mechanism 222 may be an explosion-proof valve. The pressure relief mechanism 222 may be an independent explosion-proof valve welded to a mounting hole in the bottom wall 221, or an integrated explosion-proof valve directly mounted on the bottom wall 221. In other embodiments, a heat dissipation structure and an exhaust structure may be provided on the side of the bottom wall 221 of the battery cell 20 away from the electrode assembly 23 to cool and promptly discharge the ejected material, thereby extending the service life of the entire battery device 100.

[0081] The structurally weak portion 26 is a portion where the structural strength of the component is weakened. The structurally weak portion 26 is located on the insulating film 24 .

[0082] At least a portion of the structurally weak portion 26 is positioned directly opposite the pressure relief mechanism 222 along the height direction of the battery cell 20, where the height direction of the battery cell 20 is parallel to the thickness direction of the bottom wall 221. At least a portion of the orthographic projection of the structurally weak portion 26 on the bottom wall 221 overlaps with the pressure relief mechanism 222. When a large amount of gas is generated within the battery cell 20, causing a rapid increase in pressure requiring pressure relief, the presence of the structurally weak portion 26 provides a breakthrough point for the gas. Gas generated within the electrode assembly 23 successively breaks through the obstructions of the insulating film 24 and the support member 25, quickly reaching the location of the pressure relief mechanism 222, and smoothly opening the valve to relieve pressure.

[0083] The structurally weak portion 26 in the embodiment of the present application may be of any feasible structural form, as long as it can form a relatively weak structural portion in a designated area to facilitate gas breakthrough.

[0084] By providing a structurally weak portion 26 on the insulating film 24 and making the positive projection of the structurally weak portion 26 on the bottom wall 221 at least partially overlap with the pressure relief mechanism 222, the gas can be guided along the structurally weak portion 26 to break through the obstruction of the insulating film 24, thereby facilitating directional pressure relief and improving the reliability of pressure relief of the battery cell 20. At the same time, the pressure relief mechanism is designed to be away from the electrode terminal 21a, thereby reducing the adverse effects of the ejected gas and electrolyte on the electrode terminal 21a and other components connected to the electrode terminal 21a, thereby improving the service life of the device or system in which the battery cell 20 is located.

[0085] According to some embodiments of the present application, the structurally weak portion 26 includes a groove portion 241 that is recessed along the thickness direction of the structurally weak portion 26 .

[0086] like Figure 6 As shown, the groove portion 241 refers to a groove structure that is recessed along the thickness direction of the insulating film 24 itself. The groove portion 241 can be a continuous groove or a patterned structure composed of a plurality of grooves arranged at intervals.

[0087] The groove portion 241 is provided at a portion of the insulating film 24 opposite to the bottom wall 221, that is, at a portion of the insulating film 24 located on a side of the electrode assembly 23 away from the tab 23a and directly opposite the pressure relief mechanism 222. The groove portion 241 can be provided on a side of the insulating film 24 facing the electrode assembly 23 or on a side of the insulating film 24 facing away from the electrode assembly 23.

[0088] The thickness of the insulating film 24 where the groove portion 241 is located is less than the thickness of other areas outside the groove. The depth of the groove portion 241 in the thickness direction of the insulating film 24 is not limited. For example, the depth of the groove is 1 / 3, 1 / 2, etc. of the thickness of the insulating film 24 outside the groove.

[0089] By adopting the structural design of the groove portion 241 on the insulating film 24, the isolation effect of the insulating film 24 can be taken into account while reducing the structural strength of the insulating film 24, which helps to quickly form an exhaust outlet in the event of thermal runaway and achieve reliable directional exhaust.

[0090] According to some embodiments of the present application, the groove portion 241 is an annular groove, which surrounds and forms a first closed area 242. The boundary of the first closed area 242 is the outer edge of the annular groove away from the center of the first closed area 242, and the annular groove is located within the first closed area 242.

[0091] like Figure 6 As shown, the annular grooves enclose a first closed area 242 with a closed boundary. The first closed area 242 can be any closed shape, such as a circle, a polygon, etc.

[0092] The boundary of the first closed area 242 is formed by the outer edge of the annular groove, and the annular groove is located within the range of the first closed area 242. In this way, the gas generated when thermal runaway occurs can break through the insulating film 24 along the boundary of the first closed area 242 through the annular groove.

[0093] By providing the annular groove and forming the first closed area 242 , the breakthrough area of ​​the gas through the insulating film 24 can be more accurately defined, thereby better guiding the gas flow direction and achieving reliable and accurate directional pressure relief.

[0094] According to some embodiments of the present application, the orthographic projection of the first closed area 242 on the bottom wall 221 completely falls within the range of the pressure relief mechanism 222 .

[0095] The orthographic projection of the first closed area 242 on the bottom wall 221 completely falls within the range of the pressure relief mechanism 222, which means that the first closed area 242 is arranged directly opposite the pressure relief mechanism 222 along the height direction of the battery cell 20. The size and area of ​​the first closed area 242 are smaller than or equal to the size and area of ​​the pressure relief mechanism 222.

[0096] In some examples, the first closed area 242 is a rectangle, and its orthographic projection on the bottom wall 221 is also a rectangle. The outer edge of the pressure relief mechanism 222 also forms a rectangle with the same area as the orthographic projection of the first closed area 242 on the bottom wall 221.

[0097] By making the orthographic projection of the first closed area 242 on the bottom wall 221 completely fall within the range of the pressure relief mechanism 222 , the gas can be better guided to the pressure relief mechanism 222 , thereby achieving directional pressure relief more efficiently.

[0098] According to some embodiments of the present application, the structurally weak portion 26 includes a hollow portion 243 penetrating along the thickness direction of the structurally weak portion 26 .

[0099] like Figure 7 As shown, the hollow portion 243 refers to a through structure that penetrates the thickness direction of the insulating film 24 itself, such as a through groove or through hole. The hollow portion 243 can be a continuous hollow structure or a patterned structure composed of multiple through grooves or through holes arranged at intervals.

[0100] The hollow portion 243 can significantly weaken the strength of the insulating film 24 and reduce the resistance to gas breakthrough, thereby better guiding the gas to reach the pressure relief mechanism 222 for exhaust faster, thereby improving the reliability of pressure relief.

[0101] According to some embodiments of the present application, the hollow portion 243 includes a plurality of hollow grooves 2431, which are arranged in sequence along the outer periphery of the second closed area 244. The boundary of the second closed area 244 is formed by connecting the outer edges of the plurality of hollow grooves 2431 away from the center of the second closed area 244 in sequence, and the plurality of hollow grooves 2431 are located within the second closed area 244.

[0102] like Figure 7 and Figure 8 As shown, the hollow groove 2431 is a through groove that penetrates the insulating film 24 , and the shape of the hollow groove 2431 can be circular, polygonal, elliptical, long strip or any other shape.

[0103] The plurality of hollow grooves 2431 are arranged at intervals and together form a second closed region 244 with a closed boundary. The second closed region 244 can have any closed shape, such as a circle or a polygon. The boundary of the second closed region 244 is formed by sequentially connecting the outer edges of the plurality of hollow grooves 2431, and each hollow groove 2431 is completely within the second closed region 244. In this way, the gas generated in the event of thermal runaway can pass through the plurality of hollow grooves 2431 and break through the insulating film 24 along the boundary of the second closed region 244.

[0104] It is understandable that the orthographic projections of the plurality of hollow grooves 2431 on the bottom wall 221 may be sequentially spaced along the circumference of the geometric center of the pressure relief mechanism 222. The distance between two adjacent hollow grooves 2431 may be the same or different.

[0105] The plurality of hollow grooves 2431 may be grooves of exactly the same shape and size, or may be grooves of different shapes or sizes.

[0106] By providing a plurality of spaced hollow grooves 2431 and forming a second closed area 244 , the breakthrough area of ​​the gas breaking through the insulating film 24 can be more accurately defined, thereby better guiding the gas flow and achieving reliable and accurate directional pressure relief.

[0107] According to some embodiments of the present application, the orthographic projection of the second closed area 244 on the bottom wall 221 completely falls within the range of the pressure relief mechanism 222 .

[0108] The orthographic projection of the second enclosed area 244 on the bottom wall 221 completely falls within the range of the pressure relief mechanism 222, which means that the second enclosed area 244 is arranged directly opposite the pressure relief mechanism 222 along the height direction of the battery cell 20. The size and area of ​​the second enclosed area 244 are smaller than or equal to the size and area of ​​the pressure relief mechanism 222.

[0109] In some examples, the second closed area 244 is a rectangle, and its orthographic projection on the bottom wall 221 is also a rectangle. The outer edge of the pressure relief mechanism 222 also forms a rectangle with the same area as the orthographic projection of the second closed area 244 on the bottom wall 221 .

[0110] By making the orthographic projection of the second closed area 244 on the bottom wall 221 completely fall within the range of the pressure relief mechanism 222, the gas can be better guided to the pressure relief mechanism 222, thereby achieving directional pressure relief more efficiently.

[0111] According to some embodiments of the present application, the outline of the second closed area 244 is a rectangle, the length of the long side of the outline of the second closed area 244 is A, the cumulative overlapping length of the hollow portion 243 and one of the long sides of the outline of the second closed area 244 is a, and satisfies: a / A≥50%.

[0112] In some embodiments, the outline of the second closed area 244 is a rectangle, the length of the short side of the outline of the second closed area 244 is B, the cumulative overlapping length of the hollow portion 243 and one of the short sides of the outline of the second closed area 244 is b, and satisfies: b / B ≥ 40%.

[0113] like Figure 8 As shown, the outline of the second closed area 244 is a rectangle, the length of the long side of the rectangle is A, and the length of the short side is B. The hollow portion 243 may include a plurality of hollow grooves 2431, at least some of which are arranged in sequence along a long side of the outline of the second closed area 244, and the cumulative overlapping length of the portion where the edges of these hollow grooves 2431 overlap with the second closed area 244 is a length a.

[0114] Similarly, a portion of the plurality of hollow grooves 2431 is arranged along one of the short sides of the outline of the second closed area 244, and the cumulative overlapping length of the portion of the hollow grooves 2431 that overlaps with the short side is b.

[0115] like Figure 8 As shown, the long sides of the outline of the second closed area 244 are parallel to the first direction X, and the short sides are parallel to the second direction Y. Along the first direction X, three hollow grooves 2431 overlap with the long sides, and the length of each hollow groove 2431 is a1. Therefore, the cumulative overlapping length a = a1 + a1 + a1, and a / A ≥ 50% is satisfied. Along the second direction Y, three hollow grooves 2431 overlap with the short sides, and the overlapping lengths are b1, a2, and b1, respectively. Therefore, the cumulative overlapping length b is: b = b1 + a2 + b1, and b / B ≥ 40%.

[0116] It can be understood that the cumulative overlapping length of the hollow portion 243 and the two long sides in the outline of the second closed area 244 can be equal or unequal, and the cumulative overlapping length of the hollow portion 243 and the two short sides in the outline of the second closed area 244 can be equal or unequal.

[0117] By limiting the proportion of the overlapping lengths of the hollow portion 243 and the second closed area 244 on different sides, the reliability of the gas breaking through the insulation film 24 barrier can be further improved, and the gas flow direction can be accurately guided to achieve more precise directional pressure relief.

[0118] According to some embodiments of the present application, the hollow groove 2431 is rectangular, and the long side of the hollow groove 2431 coincides with the outline of the second closed area 244 .

[0119] like Figure 8 As shown, the long side of the hollow groove 2431 coincides with the outline of the second closed area 244, which means that the hollow groove 2431 extends along the outline of the second closed area 244, so that when it is impacted by gas, it is easier to tear the insulating film 24 along the larger long side.

[0120] By limiting the shape and arrangement of the hollow grooves 2431 , the effective area where the gas breaks through the insulating film 24 can be further limited, thereby more accurately guiding the gas flow direction and improving the reliability of directional pressure relief.

[0121] According to some embodiments of the present application, the hollow groove 2431 includes a first groove 2432 and a second groove 2433, the extension direction of the first groove 2432 is parallel to the long side of the outline of the second closed area 244, and the extension direction of the second groove 2433 is parallel to the short side of the outline of the second closed area 244; the width of the first groove 2432 is b1, the width of the second groove 2433 is b2, and it satisfies: b1≥b2.

[0122] like Figure 8 As shown, the first groove 2432 and the second groove 2433 are both rectangular, the extension direction (i.e., the length direction) of the first groove 2432 is parallel to the first direction X, the width direction of the first groove 2432 is parallel to the second direction Y, the length of the first groove 2432 is a1, and the width is b1; the extension direction (i.e., the length direction) of the second groove 2433 is parallel to the second direction Y, the width direction of the second groove 2433 is parallel to the first direction X, the length of the second groove 2433 is a2, and the width is b2.

[0123] The width b1 of the first groove 2432 may be greater than the width b2 of the second groove 2433 , or may be equal to the width b2 of the second groove 2433 .

[0124] Since the long side of the outline of the second closed area 244 is larger, setting the width of the first groove 2432 extending along this direction to be greater than or equal to the width of the second groove 2433 can provide more favorable breaking conditions for the gas, so that it can smoothly break through the insulating film 24 along the second closed area 244, thereby improving the reliability of directional exhaust.

[0125] According to some embodiments of the present application, there are multiple first grooves 2432, and the widths of the multiple first grooves 2432 are all equal. In some embodiments, there are multiple second grooves 2433, and the widths of the multiple second grooves 2433 are all equal.

[0126] The widths of the plurality of first slots 2432 are equal, but the lengths may be equal or unequal. Similarly, the widths of the plurality of second slots 2433 are equal, but the lengths may be equal or unequal.

[0127] In some embodiments, the shapes and sizes of the second grooves 2433 and the second grooves 2433 may be the same.

[0128] By setting the widths of the plurality of first grooves 2432 extending in the same direction to be the same or the widths of the plurality of second grooves 2433 to be the same, the uniformity of gas penetration through the insulating film 24 can be improved.

[0129] According to some embodiments of the present application, the width b1 of the first groove 2432 satisfies: 0.5 mm ≤ b1 ≤ 4 mm.

[0130] In some embodiments, the width b2 of the second groove 2433 satisfies: 0.5 mm ≤ b2 ≤ 4 mm.

[0131] like Figure 8 As shown, the width b1 of the first groove 2432 can be specifically 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or a value between any two adjacent values ​​mentioned above.

[0132] The width b2 of the second groove 2433 can be specifically 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or a value between any two adjacent values ​​mentioned above.

[0133] By selecting a suitable width, both the isolation effect of the insulating film 24 and the reliability of gas breaking through the insulating film 24 can be taken into consideration, thereby improving the overall performance of the battery cell 20 .

[0134] According to some embodiments of the present application, the pressure relief mechanism 222 includes notches located on the surface of the bottom wall 221 .

[0135] like Figure 9 As shown, the notch refers to a concave structure on the bottom wall 221. When thermal runaway occurs, the gas pressure can break through the notch to achieve effective pressure relief.

[0136] The notches can be formed by creating weak structures at specific locations during the design and manufacturing process of the bottom wall 221, such as by laser cutting, mechanical cutting, or chemical etching to form notches on the material surface. Alternatively, after the bottom wall 221 is manufactured, a cutting tool or tool can be used to perform a material subtractive operation to form notches at specific locations.

[0137] The notches can be in the shape of a straight line, an arc, a ring or other polygons.

[0138] By introducing notches on the bottom wall 221 , directional pressure relief through the pressure relief mechanism 222 is facilitated in the event of thermal runaway, which helps to improve the reliability of pressure relief of the battery cell 20 .

[0139] According to some embodiments of the present application, the bottom wall 221 includes a first surface facing the electrode assembly 23, and a second surface away from the electrode assembly 23; wherein the notches include two first notches 2221 located on the first surface and spaced apart, and two second notches 2222 located on the second surface and spaced apart, and a third notch 2223 respectively connecting the two second notches 2222, and the extension direction of the first notch 2221 intersects with the extension direction of the second notch 2222.

[0140] like Figure 9 As shown, first notches 2221 are located on the first surface, and the area between the two first notches 2221 is the area where gas can break through the first notches 2221. Second notches 2222 are located on the second surface, and the area between the two second notches 2222 is the area where gas can break through the second notches 2222.

[0141] The extension direction of the first notch 2221 intersects the extension direction of the second notch 2222, that is, there is an angle between the two extension directions, and the angle is, for example, 30°, 45°, 60°, 75°, and 90°. The two first notches 2221 and the second notch 2222 together form a pressure relief outlet for gas to break through.

[0142] A third notch 2223 is provided between the two second notches 2222 , and the gas can divide the whole originally enclosed by the first notch 2221 and the second notch 2222 into two parts according to the third notch 2223 , and the two parts can form a split exhaust and pressure relief structure along the notches respectively.

[0143] In some embodiments, the first notch 2221 extends along the second direction Y, the second notch 2222 extends along the first direction X, and the third notch 2223 extends along the second direction Y and is respectively connected to the two second notches 2222. The two first notches 2221 and the two second notches 2222 form a rectangular pressure relief structure, and the two second notches 2222 and the third notch 2223 form an "H" shape.

[0144] By providing notches on both sides of the bottom wall 221 , the structural strength of the bottom wall 221 can be balanced, and providing a third notch 2223 between the two second notches 2222 helps to form a split exhaust structure and improve the pressure relief and exhaust efficiency.

[0145] According to some embodiments of the present application, the length of the first notch 2221 is smaller than the length of the second notch 2222 .

[0146] In some embodiments, the depth of the first score 2221 is less than the depth of at least one of the second score 2222 and the third score 2223 .

[0147] When thermal runaway occurs, the gas needs to break through the notch to achieve effective pressure relief. The longer the notch is and the deeper the notch is, the smaller the pressure required for the gas to break through the notch.

[0148] In some embodiments, the length of the first notch 2221 is smaller than the length of the second notch 2222 , and the depth of the first notch 2221 is smaller than the depth of the second notch 2222 , and the second notch 2222 is broken first.

[0149] In some embodiments, the depth of the third notch 2223 is the same as the depth of the second notch 2222, the third notch 2223 and the second notch 2222 on the pressure relief mechanism 222 are disconnected first, and the areas enclosed by the third notch 2223 and the second notch 2222 on the pressure relief mechanism 222 and the first notch 2221 respectively can be flipped along the first notch 2221 toward the side away from the electrode assembly 23 to form a split exhaust pressure relief channel.

[0150] By adopting differentiated designs for the length or depth of the notches, the pressure relief mechanism 222 is first disconnected from the notch on the second surface and flipped around the first notch 2221 to form an outlet for exhaust, thereby reducing the possibility of fragmentation due to gas impact.

[0151] According to some embodiments of the present application, the capacity of the battery cell 20 is greater than or equal to 360 Ah.

[0152] The capacity of a battery cell 20 refers to the total amount of charge that can be released by the battery cell 20 under certain discharge conditions, and is usually expressed in ampere-hours (Ah) or milliampere-hours (mAh).

[0153] It is understood that the capacity claimed in the embodiments of this application refers to the rated capacity of the battery cell. For example, for lithium batteries, the rated capacity can be determined by referring to the provisions of the Chinese standard GB / T18287-2000, or it can be determined by the minimum capacity value tested under the IEC61960 standard test conditions.

[0154] A battery cell 20 with a large capacity produces more gas and increases its internal pressure faster during thermal runaway, and thus requires higher accuracy and reliability of the directional valve opening.

[0155] Providing a structurally weak portion 26 on the insulating film 24 as described in the embodiment of the present application can improve the reliability of directional pressure relief, thereby better meeting the pressure relief requirements of large-capacity battery cells 20 and improving the overall performance of the battery cells 20.

[0156] An embodiment of the present application provides a battery device 100 , which includes the battery cell 20 in the above embodiment.

[0157] The battery device 100 of this embodiment adopts the battery cell 20 of the above embodiment and thus has the same technical effects, which will not be described in detail here.

[0158] An embodiment of the present application provides an electrical device, which includes the battery device 100 in the above embodiment, and the battery device 100 is used to provide electrical energy.

[0159] The electric device of this embodiment adopts the battery device 100 of the above embodiment and thus has the same technical effects, which will not be described in detail here.

[0160] An embodiment of the present application provides an energy storage device 200 , which includes a plurality of battery cells 20 or battery devices 100 in the above embodiments. The battery cells 20 or battery devices 100 are used to store or provide electrical energy.

[0161] The energy storage device 200 of this embodiment adopts the battery cell 20 or the battery device 100 in the above embodiments, and thus has the same technical effects, which will not be described in detail here.

[0162] An embodiment of the present application provides an energy storage system, which includes a power conversion device and the energy storage device 200 in the above embodiment. The power conversion device is used to electrically connect the power generation device and the energy storage device 200.

[0163] The energy storage system of this embodiment has the same technical effects as the energy storage device 200 in the above embodiment, and thus will not be described in detail here.

[0164] An embodiment of the present application provides a charging network, which includes a charging pile 500 and the energy storage device 200 in the above embodiment or the energy storage system in the above embodiment, and the energy storage device 200 is used to provide electrical energy to the charging pile 500.

[0165] The charging network of this embodiment has the same technical effects as the energy storage device or the above energy storage system in the above embodiments, and thus will not be described in detail here.

[0166] The present application is further described below with reference to a specific embodiment.

[0167] Combine 4 and Figure 8 As shown, the battery cell 20 includes an end cap 21 , a housing 22 , an electrode assembly 23 , an insulating film 24 and a support member 25 .

[0168] The housing 22 is formed with a housing cavity having an opening for accommodating the electrode assembly 23 and the insulating film 24. The housing 22 includes a bottom wall 221 directly opposite the opening and a side wall adjacent to the opening. A pressure relief mechanism 222 is provided on the bottom wall 221. The bottom wall 221 includes a first surface and a second surface opposing each other in the thickness direction. The pressure relief mechanism 222 may be a first notch 2221 provided on the first surface and a second notch 2222 provided on the second surface. The length of the first notch 2221 is less than the length of the second notch 2222, and the depth of the first notch 2221 is less than the depth of the second notch 2222.

[0169] The end cover 21 covers the opening of the housing 22 to seal the accommodating cavity. The end cover 21 is provided with an electrode terminal 21 a connected to the electrode assembly 23 .

[0170] The insulating film 24 is sleeved on the outer surface of the electrode assembly 23. The insulating film 24 is provided with a hollow portion 243. The hollow portion 243 includes a plurality of hollow grooves 2431. The plurality of hollow grooves 2431 are arranged in sequence along the outer periphery of the second closed area 244. The boundary of the second closed area 244 is formed by connecting the outer edges of the plurality of hollow grooves 2431 away from the center of the second closed area 244 in sequence, and the plurality of hollow grooves 2431 are located in the second closed area 244.

[0171] The orthographic projection of the second closed area 244 on the bottom wall 221 completely falls within the range of the pressure relief mechanism 222 .

[0172] The second closed area 244 has a rectangular outline, the hollowed-out groove 2431 has a rectangular outline, and the long side of the hollowed-out groove 2431 coincides with the outline of the second closed area 244. The length of the long side of the outline of the second closed area 244 is A, and the cumulative overlapping length of the hollowed-out portion 243 with one of the long sides of the outline of the second closed area 244 is a, and the following conditions are satisfied: a / A ≥ 50%. The outline of the second closed area 244 is a rectangle, the length of the short side of the outline of the second closed area 244 is B, and the cumulative overlapping length of the hollowed-out portion 243 with one of the short sides of the outline of the second closed area 244 is b, and the following conditions are satisfied: b / B ≥ 40%.

[0173] The hollow groove 2431 includes a first groove 2432 and a second groove 2433. The extension direction of the first groove 2432 is parallel to the long side of the outline of the second closed area 244, and the extension direction of the second groove 2433 is parallel to the short side of the outline of the second closed area 244; the width of the first groove 2432 is b1, the width of the second groove 2433 is b2, and it satisfies: b1≥b2.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: electrode assembly; an insulating film, sleeved on the outer surface of the electrode assembly; a shell, forming a receiving cavity with an opening, the receiving cavity being used to receive the electrode assembly and the insulating film, the shell including a bottom wall facing the opening, the bottom wall being provided with a pressure relief mechanism; as well as an end cap, covering the opening of the shell to close the accommodating cavity, the end cap being provided with an electrode terminal connected to the electrode assembly; The insulating film is provided with a structurally weak portion, and the orthographic projection of the structurally weak portion on the bottom wall at least partially overlaps with the pressure relief mechanism.

2. The battery cell according to claim 1, wherein: The structurally weak portion includes a groove portion that is recessed along the thickness direction of the structurally weak portion.

3. The battery cell according to claim 2, characterized in that: The groove portion is an annular groove, which surrounds and forms a first closed area. The boundary of the first closed area is the outer edge of the annular groove away from the center of the first closed area. The annular groove is located within the first closed area.

4. The battery cell according to claim 3, characterized in that The orthographic projection of the first closed area on the bottom wall completely falls within the range of the pressure relief mechanism.

5. The battery cell according to claim 1, characterized in that The structurally weak portion includes a hollow portion penetrating along the thickness direction of the structurally weak portion.

6. The battery cell according to claim 5, characterized in that The hollow portion includes a plurality of hollow grooves, which are arranged in sequence along the outer periphery of the second closed area. The boundary of the second closed area is formed by connecting the outer edges of the plurality of hollow grooves away from the center of the second closed area in sequence, and the plurality of hollow grooves are located within the second closed area.

7. The battery cell according to claim 6, characterized in that The orthographic projection of the second closed area on the bottom wall completely falls within the range of the pressure relief mechanism.

8. The battery cell according to claim 6, characterized in that The outline of the second closed area is a rectangle; The length of the long side of the outline of the second closed area is A, the cumulative overlapping length of the hollow portion and one of the long sides of the outline of the second closed area is a, and the following conditions are satisfied: a / A ≥ 50%; and / or The length of the short side of the outline of the second closed area is B, the cumulative overlapping length of the hollow portion and one of the short sides of the outline of the second closed area is b, and the following condition is satisfied: b / B≥40%.

9. The battery cell according to any one of claims 6 to 8, characterized in that: The hollow groove is rectangular, and the long side of the hollow groove coincides with the outline of the second closed area.

10. The battery cell according to claim 9, characterized in that The hollow groove includes: a first groove extending in a direction parallel to the long side of the outline of the second closed area, and a second groove extending in a direction parallel to a short side of the outline of the second closed area; The width of the first groove is b1, the width of the second groove is b2, and they satisfy: b1≥b2.

11. The battery cell according to claim 10, characterized in that There are multiple first grooves, and the widths of the multiple first grooves are equal; and / or There are multiple second grooves, and the widths of the multiple second grooves are equal.

12. The battery cell according to claim 10 or 11, characterized in that: The width b1 of the first groove satisfies: 0.5 mm ≤ b1 ≤ 4 mm; and / or The width b2 of the second groove satisfies: 0.5 mm ≤ b2 ≤ 4 mm.

13. The battery cell according to any one of claims 1 to 8, characterized in that: The pressure relief mechanism includes a notch located on the bottom wall surface.

14. The battery cell according to claim 13, characterized in that The bottom wall includes a first surface facing the electrode assembly and a second surface away from the electrode assembly; The notches include two first notches located on the first surface and spaced apart, two second notches located on the second surface and spaced apart, and a third notch connecting the two second notches respectively, and an extension direction of the first notch intersects with an extension direction of the second notch.

15. The battery cell according to claim 14, characterized in that The length of the first notch is smaller than the length of the second notch; and / or The depth of the first score is smaller than the depth of at least one of the second score and the third score.

16. The battery cell according to any one of claims 1 to 8, characterized in that: The capacity of the battery cell is greater than or equal to 360 Ah.

17. A battery device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 16.

18. An electrical device, characterized in that: The battery device according to claim 17 is included, and is used to provide electrical energy.

19. An energy storage device, characterized in that: The battery cell comprises a plurality of battery cells according to any one of claims 1 to 16 or a plurality of battery devices according to claim 17, wherein the battery cells or the battery devices are used to store or provide electrical energy.

20. An energy storage system, characterized in that: It comprises a power conversion device and the energy storage device as claimed in claim 19, wherein the power conversion device is used to electrically connect the power generation device and the energy storage device.

21. A charging network, characterized in that: It comprises a charging pile and the energy storage device according to claim 19 or the energy storage system according to claim 20, wherein the energy storage device or the energy storage system is used to provide electrical energy for the charging pile.

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