Battery cell, pressure relief mechanism, battery device, and electric device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
- Filing Date
- 2025-09-15
- Publication Date
- 2026-05-21
Smart Images
Figure CN2025121384_21052026_PF_FP_ABST
Abstract
Description
Battery cells, pressure relief mechanism, battery assembly and electrical device
[0001] Cross-references to related applications
[0002] This application claims priority to Chinese patent application 202411650229.X, filed on November 18, 2024, entitled “Battery cell, pressure relief mechanism, battery device and power supply device”, the entire contents of which are incorporated herein by reference. Technical Field
[0003] This application belongs to the field of battery technology, and in particular relates to a battery cell, a pressure relief mechanism, a battery device, and an electrical device. Background Technology
[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.
[0005] To address the issue of releasing high-temperature, high-pressure gases generated by electrode components under conditions such as overcharging or failure, a pressure relief mechanism is often installed on the battery. When high-temperature, high-pressure gases are generated, the grooves on the pressure relief mechanism break to quickly release the gas from the battery. However, existing pressure relief mechanisms are prone to side-spraying, causing heat diffusion. Therefore, how to reduce the risk of side-spraying from pressure relief mechanisms has become an urgent problem to be solved. Summary of the Invention
[0006] In view of the above problems, this application provides a battery cell, a pressure relief mechanism, a battery device, and an electrical device, which can reduce the risk of high-temperature gas side spray and improve the reliability of battery cell pressure relief.
[0007] In a first aspect, this application provides a battery cell including a housing, an electrode assembly, and a pressure relief mechanism. The housing has a receiving cavity, the electrode assembly is disposed in the receiving cavity, and the pressure relief mechanism is disposed in the housing. The pressure relief mechanism includes a valve body and a first groove and a second groove disposed circumferentially along the valve body. The valve body has a first surface and a second surface, the first surface being disposed away from the receiving cavity and the second surface being disposed towards the receiving cavity. The first groove is recessed from the first surface toward the side where the second surface is located, and the second groove is recessed from the second surface toward the side where the first surface is located. The valve body is configured to break in the first groove and be folded over with the second groove as an axis.
[0008] In this embodiment, by setting the first groove on the side of the valve body away from the receiving cavity and the second groove on the side of the valve body facing the receiving cavity, it is easier for the valve body to separate from the outer shell in the first groove when the internal gas pressure of the battery cell exceeds the threshold. At the same time, it solves the problem of the two sides of the second groove abutting each other during the valve body flipping process, so that the valve body opens more thoroughly, thereby reducing the risk of high temperature gas side spray and improving the reliability of battery cell pressure relief.
[0009] In some embodiments, the residual thickness of the valve body in the first groove is less than the residual thickness of the valve body in the second groove, which can more reliably cause the battery cell to burst at the first groove when the internal air pressure exceeds the threshold, thereby improving the reliability of the battery cell pressure relief.
[0010] In some embodiments, the first groove is tapered from the first surface to the second surface, and / or the second groove is tapered from the second surface to the first surface, which facilitates the breaking of the first groove and the folding of the valve body along the second groove.
[0011] In some embodiments, the second groove is offset from the first groove in the orthographic projection of the first surface, which can reduce the risk of forming a structural weak point in the junction area of the second groove and the first groove and improve the reliability of pressure relief.
[0012] In some embodiments, on the first surface, a first groove extends along a curved trajectory and has two opposing free ends along its own extending direction. The orthographic projection of a second groove on the first surface is located between the two free ends of the first groove and is spaced apart from the two free ends, so that the entire opening process of the pressure relief mechanism is simpler and more reliable.
[0013] In some embodiments, the difference between the distance between the two free ends of the first groove and the size of the second groove along the circumferential direction of the valve body ranges from 0 to 10 mm. This reduces the risk of a structural weakness forming in the area where the second groove meets the first groove, thus preventing the valve body from cracking at such a weak point. Simultaneously, it facilitates the valve body's rotation along the second groove, improving the reliability of pressure relief.
[0014] In some embodiments, the difference between the distance between the two free ends of the first groove and the size of the second groove along the circumference of the valve body ranges from 0.5 mm to 5 mm, so as to further improve the reliability of pressure relief.
[0015] In some embodiments, the second groove is disposed on one side of the second surface along the first direction, which can cause the valve body to open on one side when the internal pressure of the battery cell reaches a threshold, and flip open with the second groove as the axis to realize internal pressure relief of the battery cell.
[0016] In some embodiments, a first groove is arranged in pairs on both sides of a first surface along a first direction, and a second groove is arranged in pairs on both sides of a second surface along a second direction, the second direction intersecting the first direction. The pressure relief mechanism further includes a third groove, which is recessed from the first surface toward the side where the second surface is located, the third groove is located between the second grooves along the second direction, and the third groove extends along the first direction with its two ends respectively connected to the first grooves on both sides.
[0017] In this embodiment, when the internal pressure of the battery cell rises to a threshold, the valve body can separate from the outer casing in the third groove and the first groove, and flip open with the second groove on both sides as the axis, thereby forming a door-opening structure, which further allows the high-temperature gas inside the battery cell to be ejected in a direction perpendicular to the outer casing, reducing the risk of high-temperature gas ejection deviation.
[0018] In some embodiments, the spacing of the first groove along the first direction is smaller than the spacing of the second groove along the second direction, which can reduce the size of the third groove and reduce the risk of the third groove cracking in front of the spray valve. At the same time, it can also increase the lever arm for flipping after the spray valve, making it easier for the valve body to flip under the same force, thereby improving the reliability of the pressure relief mechanism.
[0019] In some embodiments, the housing includes a housing and a cover plate, the housing having an opening, the cover plate being disposed in the opening and connected to the housing, and at least one of the housing and the cover plate being provided with a pressure relief mechanism.
[0020] In some embodiments, the housing includes a bottom wall and a plurality of side walls, which enclose a receiving cavity with an opening. A pressure relief mechanism is disposed on the bottom wall and / or the cover plate, which can reduce the impact of high-temperature gas in the battery cell on other battery cells after it is ejected in a direction perpendicular to the housing, thereby reducing the risk of heat diffusion.
[0021] In some embodiments, the plurality of sidewalls include a pair of first sidewalls and a pair of second sidewalls, wherein the area of the first sidewall is larger than the area of the second sidewall; a first direction is parallel to the arrangement direction of the first sidewalls, and a second direction is parallel to the arrangement direction of the second sidewalls, thereby reducing the risk of the third groove rupturing due to expansion during the charging and discharging process of the battery cell and improving the reliability of the pressure relief mechanism.
[0022] In some embodiments, the second groove extends along the first direction, and the ratio of the extension dimension of the second groove along the first direction to the distance between the first groove and the first groove along the first direction is 0.1 to 0.5, so as to improve the strength of the second groove, reduce the risk of cracking, facilitate valve body flipping, and improve the reliability of pressure relief.
[0023] In some embodiments, at least a portion of the housing is made of one of the following materials: steel, aluminum alloy, and titanium alloy. These materials are heat-resistant and have high tensile strength, meeting the strength requirements of the housing, and are easy to process and have low cost.
[0024] In some embodiments, at least a portion of the housing is made of stainless steel or carbon steel. If the housing is made of stainless steel, its structural strength is high, generally meeting the tensile strength requirements under the aforementioned high-temperature conditions. Furthermore, stainless steel is less prone to rusting, thus extending the housing's service life compared to other materials. If the housing is made of carbon steel, its structural strength is high, easily meeting the tensile strength requirements under the aforementioned high-temperature conditions.
[0025] In some embodiments, at least a portion of the valve body is made of one of the following materials: steel, aluminum alloy, copper-tin-nickel alloy, and titanium alloy.
[0026] In some embodiments, at least a portion of the valve body is made of the same material as at least a portion of the housing, simplifying the structure and reducing the difficulty and cost of manufacturing individual battery cells.
[0027] In some embodiments, the electrode assembly includes a positive electrode sheet, which includes a positive electrode active material capable of reversibly de-intercalating and intercalating metal ions, and the positive electrode active material includes a nickel-containing compound.
[0028] By including nickel-containing compounds in the positive electrode active material, the energy density and cycle life of a single battery cell can be effectively increased. Although this also increases the amount of gas generated in the event of thermal runaway, the aforementioned groove structure allows for reliable venting of high-temperature gases, improving pressure relief reliability, even when the positive electrode active material includes nickel-containing compounds.
[0029] Secondly, embodiments of this application provide a pressure relief mechanism, including a valve body and a first groove and a second groove arranged circumferentially along the valve body. The valve body has a first surface and a second surface. The first groove is recessed from the first surface toward the side where the second surface is located, and the second groove is recessed from the second surface toward the side where the first surface is located. The valve body can break in the first groove and be folded with the second groove as the axis.
[0030] Thirdly, embodiments of this application provide a battery device including a plurality of battery cells according to the first aspect.
[0031] Fourthly, embodiments of this application provide an electrical device, including the battery device of the third aspect.
[0032] According to an embodiment of this application, a battery cell includes a casing, an electrode assembly, and a pressure relief mechanism. The pressure relief mechanism is disposed on the casing and includes a valve body, a first groove, and a second groove. The first groove is disposed on the side of the valve body away from the receiving cavity, and the second groove is disposed on the side of the valve body facing the receiving cavity. By disposing the first groove and the second groove on the two side surfaces of the valve body respectively, when the internal gas pressure of the battery cell exceeds a threshold, it is easier for the valve body to separate from the casing in the first groove, thus achieving reliable opening of the valve body. Simultaneously, when the valve body folds outward with the second groove as its axial direction, the problem of the two side walls of the second groove abutting each other during the valve body's folding process can be solved, resulting in a more thorough opening of the valve body. This reduces the risk of high-temperature gas ejection deviation and improves the reliability of pressure relief in the battery cell.
[0033] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.
[0035] Figure 1 is a schematic diagram of the vehicle structure provided in some embodiments of this application;
[0036] Figure 2 is an exploded schematic diagram of a battery device provided in some embodiments of this application;
[0037] Figure 3 is an exploded schematic diagram of a battery cell provided in some embodiments of this application;
[0038] Figure 4 is a cross-sectional view of a battery cell provided in some embodiments of this application;
[0039] Figure 5 is an enlarged view of point A in Figure 4;
[0040] Figure 6 is a front view of the first surface of the pressure relief mechanism provided in some embodiments of this application;
[0041] Figure 7 is a front view of the second surface of the pressure relief mechanism provided in some embodiments of this application;
[0042] Figure 8 is a cross-sectional view of a battery cell provided in some embodiments of this application;
[0043] Figure 9 is an enlarged view of point B in Figure 8;
[0044] Figure 10 is a cross-sectional view along the EE direction in Figure 8;
[0045] Figure 11 is an enlarged view of point C in Figure 10;
[0046] Figure 12 is a front view of the first surface of a pressure relief mechanism provided in some other embodiments of this application;
[0047] Figure 13 is a front view of the second surface of a pressure relief mechanism provided in some other embodiments of this application;
[0048] Figure 14 is a cross-sectional view of a battery cell provided in some other embodiments of this application;
[0049] Figure 15 is an enlarged view of point D in Figure 14;
[0050] Figure 16 is a schematic diagram of the structure of a single battery cell at one angle provided in some embodiments of this application;
[0051] Figure 17 is a structural schematic diagram of a battery cell from another angle provided in some embodiments of this application;
[0052] Figure 18 is a bottom view of a battery cell provided in some embodiments of this application.
[0053] The accompanying drawings are not necessarily drawn to scale.
[0054] Marking Explanation: 100-Battery Unit, 200-Controller, 300-Motor; 10-Battery Cell, 20-Casing; 1-Outer Shell, 11-Housing Shell, 111-Bottom Wall, 112-First Side Wall, 113-Second Side Wall, 12-Cover Plate, 13-Pressure Relief Hole, 14-Protective Sheet, 15-Exhaust Channel, 2-Electrode Assembly, 3-Pressure Relief Mechanism, 31-Valve Body, 32-First Groove, 32a-First Sub-Groove, 32b-Second Sub-Groove, 321-First Segment, 322-Second Segment, 33-Second Groove, 34-Third Groove; S1-First Surface, S2-Second Surface; X-Second Direction, Y-First Direction, Z-Third Direction. Detailed Implementation
[0055] 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.
[0056] It should be noted that, unless otherwise stated, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by those skilled in the art to which the embodiments of this application pertain.
[0057] 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", "circumferential", etc., 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 do not 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.
[0058] Furthermore, technical terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise explicitly defined.
[0059] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the 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.
[0060] In the description of the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0061] 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.
[0062] Typically, a battery includes a casing and a pressure relief mechanism mounted on the casing. This mechanism includes a valve body and a groove within the valve body. When the battery pressure rises to a threshold, the valve body separates from the casing and flips open along the groove, releasing the gas inside the battery to alleviate internal pressure and reduce the risk of explosion. However, in actual pressure relief, after the valve body flips open a certain angle around the groove, the two sides of the groove abut against each other, making it difficult for the valve body to continue flipping open. This causes the valve body to block the ejected high-temperature gas on one side during pressure relief, allowing the high-temperature gas and flame from the battery cell to escape to the other side, thus transferring heat to adjacent battery cells and causing heat diffusion.
[0063] Based on the above considerations, in order to reduce the risk of thermal diffusion, this application provides an embodiment of a new battery cell. By having the opening of the first groove for blasting face outwards from the battery cell and the opening of the second groove for connection face inwards from the battery cell, it is possible to reliably achieve pressure relief at the valve opening while solving the problem of the groove walls on both sides abutting each other during the valve body flipping process. This allows the valve body to open more thoroughly, improves the shielding of high-temperature gas discharge, and reduces the risk of high-temperature gas ejection deviation.
[0064] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.
[0065] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. This application does not impose any special limitations on the above-mentioned electrical devices.
[0066] It should be understood that the technical solutions described in the embodiments of this application are applicable to all electrical devices including battery device 100 and those using batteries, but for the sake of brevity, the following embodiments are all described using electric vehicles as examples.
[0067] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.
[0068] The vehicle has a battery device 100 installed inside, which can be located at the bottom, front, or rear of the vehicle. The battery device 100 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The vehicle may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the vehicle's power needs during starting, navigation, and driving.
[0069] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application.
[0070] The battery device 100 mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells 10, which are connected in series, parallel, or mixed connections via a busbar. A battery cell assembly may be a battery module, which is formed by arranging and fixing multiple battery cells 10 into an independent module.
[0071] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 20 and one or more battery cell assemblies. The battery cell assemblies are housed in the housing 20 to encapsulate one or more battery cells 10 and prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells 10.
[0072] In this embodiment of the application, the battery cell 10 can be a secondary battery, which refers to the battery cell 10 that can be used again after being discharged by recharging to activate the active material.
[0073] The battery cell 10 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.
[0074] Please refer to Figures 3 to 7 together. Figure 3 shows an exploded view of a battery cell 10 provided in some embodiments of this application. Figure 4 shows a cross-sectional view of a battery cell 10 provided in some embodiments of this application. Figure 5 shows an enlarged view of point A in Figure 4. Figures 6 and 7 show front views of the first surface S1 and the second surface S2 of the pressure relief mechanism 3 provided in some embodiments of this application, respectively.
[0075] The battery cell 10 in this embodiment includes a housing 1, an electrode assembly 2, and a pressure relief mechanism 3. The housing 1 has a receiving cavity, the electrode assembly 2 is disposed in the receiving cavity, and the pressure relief mechanism 3 is disposed in the housing 1. The pressure relief mechanism 3 includes a valve body 31 and a first groove 32 and a second groove 33 disposed circumferentially along the valve body 31. The valve body 31 has a first surface S1 and a second surface S2. The first surface S1 is disposed away from the receiving cavity, and the second surface S2 is disposed towards the receiving cavity. The first groove 32 is recessed from the first surface S1 toward the side where the second surface S2 is located, and the second groove 33 is recessed from the second surface S2 toward the side where the first surface S1 is located. The valve body 31 is configured to break in the first groove 32 and be folded over with the second groove 33 as an axis.
[0076] In this embodiment, the battery cell 10 has a pressure relief mechanism 3 disposed on the outer casing 1 and includes a valve body 31, a first groove 32, and a second groove 33. The first groove 32 is disposed on the side of the valve body 31 away from the receiving cavity, and the second groove 33 is disposed on the side of the valve body 31 facing the receiving cavity. By disposing the first groove 32 and the second groove 33 on the two side surfaces of the valve body 31, when the internal gas pressure of the battery cell 10 exceeds a threshold, it is easier for the valve body 31 to separate from the outer casing 1 via the first groove 32, thus achieving reliable opening of the valve body 31. Simultaneously, when the valve body 31 folds outward with the second groove 33 as its axial direction, the problem of the two side walls of the second groove 33 abutting against each other during the folding process can be solved, allowing the valve body 31 to open more thoroughly. This reduces the risk of high-temperature gas ejection deviation and improves the reliability of pressure relief in the battery cell 10.
[0077] It is understood that, for ease of description, the first surface S1 is defined as the inner surface, and the second surface S2 is defined as the outer surface. Since the first groove 32 is located on the outer surface of the outer casing 1, when the internal gas pressure of the battery cell 10 exceeds the threshold, the first groove 32 will be subjected to greater shear stress and burst first, causing the valve body 31 to preferentially separate from the outer casing 1 at the first groove 32 and fold outward with the second groove 33 as the axial direction. Since the second groove 33 is located on the inner surface of the outer casing 1, when the valve body 31 folds outward with the second groove 33 as the axial direction, the opening of the second groove 33 gradually opens, and its two side walls will not abut against each other during the folding process of the valve body 31. Therefore, it will not restrict the further opening of the valve body 31, and the valve body 31 can open to be flush with the outer casing 1, thereby allowing the high-temperature gas inside the battery cell 10 to be ejected in a direction perpendicular to the outer casing 1, reducing the risk of high-temperature gas ejection deviation.
[0078] Please refer to Figures 3 to 11. Figures 8 and 9 show cross-sectional views of the battery cell 10 at the first groove 32 in some embodiments of this application, and Figures 10 and 11 show cross-sectional views of the battery cell 10 at the second groove 33 in some embodiments of this application.
[0079] In some alternative embodiments, the residual thickness T1 of the valve body 31 in the first groove 32 is less than the residual thickness T2 of the valve body 31 in the second groove 33.
[0080] Wherein, the residual thickness T1 of the valve body 31 in the first groove 32 refers to the distance between the bottom of the first groove 32 and the second surface S2 after the first groove 32 is recessed from the first surface S1 of the valve body 31 toward the side where the second surface S2 is located. The residual thickness T2 of the valve body 31 in the second groove 33 refers to the distance between the bottom of the second groove 33 and the first surface S1 after the second groove 33 is recessed from the second surface S2 toward the side where the first surface S1 is located.
[0081] By making the residual thickness T1 of the valve body 31 in the first groove 32 smaller than the residual thickness T2 of the valve body 31 in the second groove 33, it is possible to more reliably cause the battery cell 10 to burst at the first groove 32 when the internal air pressure exceeds the threshold, so that the valve body 31 is preferentially separated from the outer casing 1 at the first groove 32, thereby improving the reliability of the pressure relief of the battery cell 10.
[0082] Optionally, the ratio of the residual thickness T2 of the valve body 31 in the second groove 33 to the residual thickness T1 of the valve body 31 in the first groove 32 is 1.1 to 3.
[0083] By ensuring that the ratio of the residual thickness T2 of the valve body 31 in the second groove 33 to the residual thickness T1 of the valve body 31 in the first groove 32 is greater than or equal to 1.1, the battery cell 10 can burst at the first groove 32 when the internal gas pressure exceeds the threshold. This also reduces the risk of the valve body 31 separating from the outer casing 1 at the second groove 33 and flying out as a whole, thus improving the reliability of pressure relief. Furthermore, by ensuring that the ratio of the residual thickness T2 of the valve body 31 in the second groove 33 to the residual thickness T1 of the valve body 31 in the first groove 32 is less than or equal to 3, it is easier for the valve body 31 to fold over at the second groove 33 after separating from the outer casing 1 at the first groove 32, thereby achieving reliable pressure relief of the battery cell 10.
[0084] Optionally, the ratio of the residual thickness T2 of the valve body 31 in the second groove 33 to the residual thickness T1 of the valve body 31 in the first groove 32 can be further set to 1.2 to 2. The residual thickness T2 of the valve body 31 in the second groove 33 and the residual thickness T1 of the valve body 31 in the first groove 32 can be adjusted according to the actual pressure relief, so as to meet the requirement that the valve body 31 breaks in the first groove 32 and folds over with the second groove 33 as the axis.
[0085] In some alternative embodiments, the first groove 32 is tapered from the first surface S1 to the second surface S2, and / or the second groove 33 is tapered from the second surface S2 to the first surface S1. By tapering the first groove 32 from the first surface S1 to the second surface S2, it is easier for the first groove 32 to break and for the valve body 31 to fold along the second groove 33.
[0086] Optionally, the cross-sectional shape of the first groove 32 and / or the second groove 33 along its extension direction includes an inverted triangle or an inverted trapezoid, and the included angle between the two side walls of the first groove 32 and / or the second groove 33 can be set to 30° to 150°.
[0087] Please refer to Figures 3 to 11. In some optional embodiments, the second groove 33 is offset from the first groove 32 in the orthographic projection of the first surface S1. This can reduce the risk of a structural weak point forming in the area where the second groove 33 and the first groove 32 meet. As a result, the valve body 31 can more reliably break off from the first groove 32 and fold over with the second groove 33 as the axis, thereby improving the reliability of pressure relief.
[0088] Specifically, on the first surface S1, the first groove 32 extends along a curved trajectory and has two opposite free ends along its own extension direction. The second groove 33 is located between the two free ends of the first groove 32 and is spaced apart from the two free ends by the orthographic projection of the first surface S1.
[0089] That is, the first groove 32 and the second groove 33 can form a racetrack-shaped groove along the circumference of the valve body 31. By extending the first groove 32 along the curved trajectory, when the internal pressure of the battery cell 10 reaches the threshold, the valve body 31 can separate from the outer shell 1 along the curved trajectory of the first groove 32. After separating to the two free ends of the first groove 32, it folds with the second groove 33 located between the two free ends as the axis, making the entire opening process of the pressure relief mechanism 3 simpler and more reliable.
[0090] Optionally, along the circumference of the valve body 31, the difference between the distance H1 between the two free ends of the first groove 32 and the size H2 of the second groove 33 is in the range of 0 to 10 mm.
[0091] By ensuring that the difference between the distance H1 between the two free ends of the first groove 32 and the dimension H2 of the second groove 33 is greater than 0, the risk of a structural weakness forming in the junction area of the second groove 33 and the first groove 32 can be reduced, thus preventing the valve body 31 from cracking at such a weak point. Furthermore, by ensuring that the difference between the distance H1 between the two free ends of the first groove 32 and the dimension H2 of the second groove 33 is less than or equal to 10 mm, it is easier for the valve body 31 to rotate along the second groove 33, improving the reliability of pressure relief.
[0092] Optionally, along the circumference of the valve body 31, the difference between the distance between the two free ends of the first groove 32 and the size of the second groove 33 is in the range of 0.5mm to 5mm, so as to further improve the reliability of pressure relief.
[0093] Understandably, the pressure relief mechanism 3 can be configured in various structural forms.
[0094] Please refer to Figures 3 to 11. In some optional embodiments, the second groove 33 is disposed on one side of the second surface S2 along the first direction Y. At this time, the first groove 32 can be disposed on the other side of the first surface S1 along the first direction Y, and the two free ends of the first groove 32 extend toward the second groove 33 along the first direction Y and enclose to form a pressure relief space.
[0095] By setting the second groove 33 along the first direction Y on one side of the second surface S2, when the internal pressure of the battery cell 10 reaches a threshold, the valve body 31 can be opened on one side and flipped open around the second groove 33 as an axis to achieve internal pressure relief of the battery cell 10. The above structure is simple and reliable. At the same time, since the valve body 31 can be flipped to fit against the outer shell 1, it can also improve the shielding of high-temperature gas discharge and reduce the risk of thermal diffusion when the battery cell 10 is sprayed.
[0096] Please refer to Figures 12 to 15. Figures 12 and 13 show front views of the first surface S1 and the second surface S2 of the pressure relief mechanism 3 provided in another embodiment of this application, respectively. Figures 14 and 15 show cross-sectional views of the battery cell 10 at the third groove 34.
[0097] In some alternative embodiments, first grooves 32 are arranged in pairs along the first direction Y on both sides of the first surface S1, and second grooves 33 are arranged in pairs along the second direction X on both sides of the second surface S2, the second direction X intersecting the first direction Y. The pressure relief mechanism 3 also includes a third groove 34, which is recessed from the first surface S1 toward the side where the second surface S2 is located. The third groove 34 is located between the second grooves 33 along the second direction X, and extends along the first direction Y with its two ends connected to the first grooves 32 on both sides respectively.
[0098] By setting the second groove 33 along the second direction X on both sides of the second surface S2, and setting the third groove 34 between the paired first grooves 32, when the internal pressure of the battery cell 10 rises to the threshold, the valve body 31 can separate from the outer shell 1 through the third groove 34 and the first groove 32, and flip open with the second groove 33 on both sides as the axis, thereby forming a door-opening structure, which further allows the high-temperature gas inside the battery cell 10 to be ejected in a direction perpendicular to the outer shell 1, reducing the risk of high-temperature gas ejection deviation.
[0099] For ease of description, the paired first grooves 32 are defined as the first sub-groove 32a and the second sub-groove 32b, and the two ends of the third groove 34 are connected to the first sub-groove 32a and the second sub-groove 32b, respectively. When the internal pressure of the battery cell 10 rises to a threshold, the valve body 31 will first separate from the outer casing 1 in the third groove 34 and split into two sub-valve bodies. One sub-valve body separates from the outer casing 1 in one side of the first sub-groove 32a and the second sub-groove 32b and flips open with the second groove 33 on that side as the axis. The other sub-valve body separates from the outer casing 1 in the other side of the first sub-groove 32a and the second sub-groove 32b and flips open with the second groove 33 on that side. This allows the door to be opened from both sides of the pressure relief space to relieve pressure and reduce the risk of bias.
[0100] Optionally, the first grooves 32 arranged in pairs are symmetrically arranged relative to the valve body 31, and in the first direction Y, the two ends of the third groove 34 are respectively connected to the middle of the first grooves 32.
[0101] The first sub-groove 32a and the second sub-groove 32b are symmetrically arranged relative to the valve body 31. One end of the third groove 34 is connected to the middle of the first sub-groove 32a, and the other end is connected to the middle of the second sub-groove 32b, so that the valve body 31 can be opened synchronously from both sides. At the same time, during the service life of the battery cell 10, the first sub-groove 32a and the second sub-groove 32b are always subjected to balanced internal pressure, so that the pressure relief mechanism 3 will not experience performance degradation under long-term stress.
[0102] In some alternative implementations, the first groove 32 includes an intersecting first groove segment 321 and a second groove segment 322. The first groove segment 321 extends along a second direction X, and the second groove segment 322 is disposed opposite to both ends of the first groove segment 321 along the second direction X. The paired first grooves 32 extend a certain distance toward each other along a first direction Y, and their ends are spaced apart from each other.
[0103] Both the first sub-groove 32a and the second sub-groove 32b include a first groove segment 321 and a second groove segment 322. The second groove segments 322 of the first sub-groove 32a and the second groove segments 322 of the second sub-groove 32b extend toward each other, thereby increasing the fracture length of the pressure relief mechanism 3 and making it easier to flip open from both sides of the pressure relief space, thus improving the reliability of the flip opening. Furthermore, by arranging the ends of the second groove segments 322 of the first sub-groove 32a and the second groove segments 322 of the second sub-groove 32b at intervals, the risk of the valve body 31 flying out entirely during valve ejection and causing a secondary accident can be reduced, thus improving the reliability of the pressure relief mechanism 3.
[0104] Optionally, for the first sub-groove 32a and / or the second sub-groove 32b, the first groove segment 321 may be arranged to extend in a straight line, and the second groove segment 322 may be arranged to extend in a curve, thereby playing a guiding role and preventing stress concentration between the first groove segment 321 and the second groove segment 322, thus improving the reliability of tearing.
[0105] In some alternative embodiments, the ratio of the residual thickness T3 of the valve body 31 in the third groove 34 to the residual thickness T1 of the valve body 31 in the first groove 32 is 0.8 to 1.2.
[0106] The residual thickness T3 of the valve body 31 in the third groove 34 refers to the distance between the bottom of the third groove 34 and the second surface S2 after the third groove 34 is recessed from the first surface S1 of the valve body 31 toward the side where the second surface S2 is located.
[0107] By ensuring that the ratio of the residual thickness T3 of the valve body 31 in the third groove 34 to the residual thickness T1 of the valve body 31 in the first groove 32 is greater than or equal to 0.8, the valve body 31 can smoothly separate from the housing 11 via the first groove 32 after the third groove 34 breaks. Furthermore, by ensuring that the residual thickness T3 of the valve body 31 in the third groove 34 is less than or equal to 1.2 to the residual thickness T1 of the valve body 31 in the first groove 32, the risk of the first groove 32 breaking first can be reduced. This allows for reliable sequential breakage from the third groove 34 to the first groove 32 during valve operation, enabling the valve body 31 to flip open.
[0108] Optionally, the residual thickness T3 of the valve body 31 in the third groove 34 can be equal to the residual thickness T1 of the valve body 31 in the first groove 32, so as to reduce the manufacturing difficulty of the pressure relief mechanism 3.
[0109] In some alternative embodiments, the spacing of the second groove 33 along the first direction Y is smaller than the spacing of the first groove 32 along the second direction X.
[0110] By making the spacing of the second groove 33 along the first direction Y smaller than the spacing of the first groove 32 along the second direction X, the size of the third groove 34 can be reduced, thus lowering the risk of the third groove 34 cracking in front of the spray valve. Simultaneously, the distance between the third groove 34 and the second groove 33 can be increased, i.e., the lever arm for flipping can be increased, making it easier to flip under the same force. This facilitates the flipping and opening of the valve body 31 after the spray valve, and also allows the entire pressure relief mechanism 3 to open more thoroughly, thereby further reducing the risk of high-temperature gas ejection deviation and improving the reliability of pressure relief for the battery cell 10.
[0111] Optionally, the cross-sectional shape of the third groove 34 along the first direction Y can be set as an inverted trapezoid or an inverted triangle, etc. At least one of the first groove 32, the second groove 33 and the third groove 34 can be formed by stamping or CNC machining, which can make the groove wall smoother, and the burst pressure can be controlled by controlling the stamping depth, so that when the internal pressure of the battery cell reaches the threshold, the outer casing 1 will break from the pressure relief mechanism 3 first, instead of breaking from other parts.
[0112] Please refer to Figures 12 to 17. Figures 16 and 17 show schematic diagrams of the battery cell 10 at different angles. In some alternative embodiments, the housing 1 includes a housing 11 and a cover plate 12. The housing 11 has an opening, and the cover plate 12 is disposed in the opening and connected to the housing 11. At least one of the housing 11 and the cover plate 12 is provided with a pressure relief mechanism 3.
[0113] The housing 11 is an assembly used in conjunction with the cover plate 12 to form the internal environment of the battery cell 10, wherein the formed internal environment can accommodate the electrode assembly 2, electrolyte, and other components. The housing 11 and the cover plate 12 can be separate components. The housing 11 encloses a receiving cavity with an opening along the third direction Z, and the cover plate 12 closes the opening and isolates the internal environment of the battery cell 10 from the external environment. Here, the third direction Z is the height direction of the battery cell 10.
[0114] Optionally, the provision of a pressure relief mechanism 3 on at least one of the housing 11 and the cover plate 12 means that the pressure relief mechanism 3 can be provided only on the housing 11, only on the cover plate 12, or both the housing 11 and the cover plate 12 can be provided with the pressure relief mechanism 3.
[0115] When the pressure relief mechanism 3 is installed on the housing 11, it can be installed on the bottom wall 111 of the housing 11 or on the side wall of the housing 11. When the pressure relief mechanism 3 is installed on the cover plate 12, since the housing 1 can have an opening at one end along the third direction Z or both ends along the third direction Z, when both ends of the housing 1 are provided with cover plates 12, the pressure relief mechanism 3 can be installed on one side of the cover plate 12 or on both sides of the cover plates 12. The position of the pressure relief mechanism 3 on the housing 1 and the specific position of the pressure relief mechanism 3 on the housing 11 or the cover plate 12 can be adjusted according to actual needs, as long as the pressure relief requirements of the battery are met.
[0116] In some embodiments, the housing 11 includes a bottom wall 111 and a plurality of side walls, the bottom wall 111 and the plurality of side walls enclosing a receiving cavity with an opening, and a pressure relief mechanism 3 is disposed on the bottom wall 111 and / or the cover plate 12.
[0117] By placing the pressure relief mechanism 3 on the bottom wall 111 and / or the cover plate 12, the impact of the high-temperature gas inside the battery cell 10 on other battery cells 10 after it is ejected in a direction perpendicular to the outer casing 1 can be reduced, thereby reducing the risk of heat diffusion.
[0118] Optionally, the battery cell 10 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 square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.
[0119] In some alternative embodiments, the plurality of sidewalls include a pair of first sidewalls 112 and a pair of second sidewalls 113, wherein the area of the first sidewall 112 is larger than the area of the second sidewall 113. A first direction Y is parallel to the arrangement direction of the first sidewalls 112, and a second direction X is parallel to the arrangement direction of the second sidewalls 113.
[0120] At this time, the first direction Y is the length direction of the battery cell 10, and the second direction X is the width direction of the battery cell 10.
[0121] When the pressure relief mechanism 3 is installed on the bottom wall 111 and / or the cover plate 12, the third groove 34 can extend along the width direction of the battery cell 10. Since the expansion deformation of the first side wall 112 is greater than that of the second side wall 113 during the charging and discharging process of the battery cell 10, the above arrangement can reduce the risk of the third groove 34 rupturing due to expansion during the charging and discharging process of the battery cell 10, and improve the reliability of the pressure relief mechanism 3.
[0122] In some alternative embodiments, the second groove 33 extends along the first direction Y, and the ratio of the extension dimension of the second groove 33 along the first direction Y to the distance between the first groove 32 and the first groove 32 along the first direction Y is 0.1 to 0.5.
[0123] By making the ratio of the extension dimension W1 of the second groove 33 along the first direction Y to the distance W2 of the first groove 32 along the first direction Y greater than or equal to 0.1, the strength of the second groove 33 can be improved and the risk of cracking of the second groove 33 can be reduced when the valve body 31 is flipped open from both sides. Furthermore, by making the ratio of the extension dimension W1 of the second groove 33 along the first direction Y to the distance W2 of the first groove 32 along the first direction Y less than or equal to 0.5, the valve body 31 can be easily flipped, improving the reliability of pressure relief.
[0124] Please refer to Figures 3, 12 to 18. Figure 18 shows a bottom view of a battery cell 10 provided in some embodiments of this application.
[0125] In some alternative embodiments, the housing 1 includes a pressure relief hole 13 and a protective plate 14. The pressure relief mechanism 3 is disposed within the pressure relief hole 13, and the protective plate 14 is disposed on the housing 1 and covers the pressure relief hole 13. The housing 1 is provided with an exhaust groove 15, which extends to the pressure relief hole 13 and communicates with the pressure relief space.
[0126] The protective plate 14 has sufficient strength and toughness to protect the pressure relief mechanism 3 from external damage. The venting groove 15 can be configured as a V-groove to maintain the air pressure inside and outside the pressure relief hole 13. Optionally, a leakage detection element can be provided at the V-groove to detect whether there is any leakage of electrolyte in the battery due to substandard welding quality in the pressure relief mechanism 3.
[0127] In some optional embodiments, there are multiple exhaust grooves 15, with some exhaust grooves 15 corresponding to the first groove 32 and some exhaust grooves 15 corresponding to the third groove 34. By providing multiple exhaust grooves 15 and making the exhaust grooves 15 correspond to the first groove 32 and the third groove 34 respectively, the pressure relief mechanism 3 can be detected more reliably, thereby improving the reliability of the pressure relief mechanism 3.
[0128] In the current ternary system, especially the high-nickel silicon system, it is necessary to be able to withstand the high temperature problem during thermal runaway. Therefore, the outer shell 1 needs to be made of a high-temperature resistant material.
[0129] In some alternative embodiments, at least a portion of the casing 1 is made of one of the following materials: steel, aluminum alloy, and titanium alloy. These materials are heat-resistant and have high tensile strength, which improves the deformation capacity of this portion of the casing in the event of thermal runaway of a single battery cell. This makes the casing less susceptible to rapid damage and explosion, thereby reducing the risk of thermal runaway of adjacent battery cells and improving battery reliability.
[0130] Optionally, at least a portion of the outer casing 1 may be made of stainless steel or carbon steel. Specific stainless steel grades may include SUS304, SUS305, and SUS316L, while specific carbon steel grades may include SPCC. If the outer casing 1 is made of stainless steel, its structural strength is high, typically meeting the tensile strength requirements under the aforementioned high-temperature conditions. Furthermore, stainless steel is less prone to rusting, thus extending the service life of the outer casing 1 compared to other materials. If the outer casing 1 is made of carbon steel, its structural strength is high, easily meeting the tensile strength requirements under the aforementioned high-temperature conditions.
[0131] Optionally, when at least a portion of the material of the housing 1 includes aluminum alloy, the aluminum alloy may specifically be AL3003; when at least a portion of the material of the housing 1 includes titanium alloy, the titanium alloy may specifically be TC1 or TC4, etc.
[0132] In some alternative embodiments, at least a portion of the valve body 31 is made of one of the following materials: steel, aluminum alloy, copper-tin-nickel alloy, and titanium alloy.
[0133] Optionally, at least a portion of the valve body 31 is made of the same material as at least a portion of the housing 1, which simplifies the structure and reduces the manufacturing difficulty and cost of the battery cells.
[0134] For example, when at least a portion of the housing 1 is made of titanium alloy, the valve body 31 can be made of TC1 or TC4, etc. When at least a portion of the housing 1 is made of aluminum alloy, the valve body 31 can be made of MF X2, AL 3003, or AL 1060, etc. When at least a portion of the housing 1 is made of steel, the valve body 31 can be made of SUS304, SUS305, SUS316L, or SPCC, etc.
[0135] In some alternative embodiments, the electrode assembly 2 includes a positive electrode sheet, which includes a positive active material capable of reversibly extracting and inserting metal ions, and the positive active material includes a nickel-containing compound.
[0136] By including nickel-containing compounds in the positive electrode active material of the positive electrode sheet, the energy density and cycle life of the battery cell can be effectively increased. Although this will also increase the gas generated in the event of thermal runaway in the battery cell 10, the aforementioned groove structure allows for reliable discharge of high-temperature gases, improving pressure relief reliability, even when the positive electrode active material includes nickel-containing compounds.
[0137] Optionally, the electrode assembly 2 further includes a negative electrode sheet, which includes a negative electrode active material capable of reversibly extracting and inserting metal ions, and the negative electrode active material includes a silicon-based material.
[0138] Please refer to Figures 1 to 18. The structure of the battery cell 10 in one embodiment of this application will be described below.
[0139] The battery cell 10 provided in this application embodiment includes a housing 1, an electrode assembly 2, and a pressure relief mechanism 3. The housing 1 has a receiving cavity, the electrode assembly 2 is disposed in the receiving cavity, and the pressure relief mechanism 3 is disposed in the housing 1. The pressure relief mechanism 3 includes a valve body 31 and a first groove 32 and a second groove 33 disposed circumferentially along the valve body 31.
[0140] The valve body 31 has a first surface S1 and a second surface S2. The first surface S1 is disposed away from the receiving cavity, and the second surface S2 is disposed towards the receiving cavity. A first groove 32 is recessed from the first surface S1 toward the side where the second surface S2 is located. The first groove 32 extends along a curved trajectory and has two opposite free ends along its own extension direction. A second groove 33 is disposed on one side of the second surface S2 along the first direction Y, and the orthographic projection of the second groove 33 on the first surface S1 is located between the two free ends of the first groove 32 and is spaced apart from the two free ends. It is recessed from the second surface S2 toward the side where the first surface S1 is located. The residual thickness of the valve body 31 in the first groove 32 is less than the residual thickness of the valve body 31 in the second groove 33. The valve body 31 is configured to break in the first groove 32 and be folded with the second groove 33 as the axis.
[0141] In this embodiment, the battery cell 10, by placing the first groove 32 on the side of the valve body 31 away from the receiving cavity and the second groove 33 on the side of the valve body 31 facing the receiving cavity, facilitates the separation of the valve body 31 from the outer casing 1 through the first groove 32 when the internal gas pressure of the battery cell 10 exceeds a threshold, thus enabling reliable opening of the valve body 31. Simultaneously, when the valve body 31 folds outward with the second groove 33 as its axial direction, it solves the problem of the two sides of the second groove 33 abutting against each other during the folding process, allowing the valve body 31 to open more thoroughly. This reduces the risk of high-temperature gas ejection deviation and improves the reliability of pressure relief in the battery cell 10.
[0142] It should be noted that the pressure relief mechanism 3 disclosed in this application embodiment can be used in the battery cell 10 and as a component of the battery cell 10, or it can be manufactured or sold as an independent component. That is, the pressure relief mechanism 3 can be used in all battery devices 100 including battery cells 10 and electrical devices including the battery device 100, but it is not limited to battery cells 10. The pressure relief mechanism 3 disclosed in this application can also be used to relieve pressure in other products when the internal pressure is greater than a threshold, and can increase the freedom and operability of product design.
[0143] 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 single battery cell, comprising: The outer shell has a receiving cavity; Electrode assembly is disposed in the receiving cavity; A pressure relief mechanism is disposed in the housing, the pressure relief mechanism including a valve body and a first groove and a second groove disposed circumferentially along the valve body; The valve body has a first surface and a second surface, the first surface being disposed away from the receiving cavity and the second surface being disposed towards the receiving cavity, the first groove being recessed from the first surface toward the side where the second surface is located, the second groove being recessed from the second surface toward the side where the first surface is located, and the valve body being configured to break at the first groove and be folded with the second groove as an axis.
2. The battery cell of claim 1, wherein, The residual thickness of the valve body in the first groove is less than the residual thickness of the valve body in the second groove.
3. The battery cell of claim 1 or 2, wherein, The first groove is tapered from the first surface to the second surface, and / or the second groove is tapered from the second surface to the first surface.
4. The battery cell of any one of claims 1 to 3, wherein, The orthographic projection of the second groove onto the first surface is offset from that of the first groove.
5. The battery cell of claim 4, wherein, On the first surface, the first groove extends along a curved trajectory and has two opposing free ends along its own extending direction. The orthographic projection of the second groove on the first surface is located between the two free ends of the first groove and is spaced apart from the two free ends.
6. The battery cell of claim 5, wherein, Along the circumference of the valve body, the difference between the distance between the two free ends of the first groove and the size of the second groove ranges from 0 to 10 mm.
7. The battery cell of claim 6, wherein, Along the circumference of the valve body, the difference between the distance between the two free ends of the first groove and the size of the second groove ranges from 0.5 mm to 5 mm.
8. The battery cell of any one of claims 1 to 7, wherein, The second groove is disposed on one side of the second surface along the first direction.
9. The battery cell of any one of claims 1 to 7, wherein, The first groove is arranged in pairs on both sides of the first surface along a first direction, and the second groove is arranged in pairs on both sides of the second surface along a second direction, the second direction intersecting the first direction; The pressure relief mechanism further includes a third groove, which is recessed from the first surface toward the side where the second surface is located. The third groove is located between the second grooves along the second direction, and extends along the first direction with its two ends connected to the first grooves on both sides.
10. The battery cell of claim 9, wherein, The spacing between the first grooves along the first direction is less than the spacing between the second grooves along the second direction.
11. The battery cell of claim 9, wherein, The outer casing includes a housing and a cover plate. The housing has an opening, and the cover plate is disposed in the opening and connected to the housing. The pressure relief mechanism is provided on at least one of the housing and the cover plate.
12. The battery cell of claim 11, wherein, The housing includes a bottom wall and multiple side walls, which together form a receiving cavity with the opening. The pressure relief mechanism is disposed on the bottom wall and / or the cover plate.
13. The battery cell of claim 12, wherein, The plurality of sidewalls include a pair of first sidewalls and a pair of second sidewalls, wherein the area of the first sidewall is greater than the area of the second sidewall; The first direction is parallel to the arrangement direction of the first sidewall, and the second direction is parallel to the arrangement direction of the second sidewall.
14. The battery cell of claim 9, wherein, The second groove extends along the first direction, and the ratio of the extension dimension of the second groove along the first direction to the distance between the first groove and the first groove along the first direction is 0.1 to 0.
5.
15. The battery cell of any one of claims 1 to 14, wherein, The material of at least a portion of the outer casing includes one of the following: steel, aluminum alloy, and titanium alloy.
16. The battery cell of claim 15, wherein, The material of at least a portion of the outer casing includes stainless steel or carbon steel.
17. The battery cell of any one of claims 1 to 16, wherein, The material of at least a portion of the valve body includes one of the following: steel, aluminum alloy, copper-tin-nickel alloy, and titanium alloy.
18. The battery cell of any one of claims 1 to 17, wherein, The material of at least a portion of the valve body is the same as the material of at least a portion of the housing.
19. The battery cell of any one of claims 1 to 18, wherein, The electrode assembly includes a positive electrode sheet, which includes a positive electrode active material capable of reversibly extracting and inserting metal ions, and the positive electrode active material includes a nickel-containing compound.
20. A pressure relief mechanism, comprising a valve body and a first groove and a second groove disposed circumferentially along the valve body; The valve body has a first surface and a second surface. The first groove is recessed from the first surface toward the side where the second surface is located, and the second groove is recessed from the second surface toward the side where the first surface is located. The valve body can break in the first groove and be folded with the second groove as the axis.
21. A battery device comprising a plurality of battery cells according to any one of claims 1-19.
22. An electrical device comprising the battery device as described in claim 21.