Battery cell, pressure relief mechanism, battery device, and electric device

Abstract

Provided in the present application are a battery cell, a pressure relief mechanism, a battery device, and an electric device. The battery cell comprises a housing, an electrode assembly, and a pressure relief mechanism. The housing has an accommodating cavity; the electrode assembly is arranged in the accommodating cavity; the pressure relief mechanism is arranged on the housing; the pressure relief mechanism comprises a valve body, and first grooves and a second groove arranged on the valve body; the pair of first grooves extend in a first direction and are spaced apart from each other in a second direction; a pressure relief space is formed between the first grooves, and the dimension of the pressure relief space in the first direction is larger than the dimension thereof in the second direction; the second groove is connected to the first grooves on two sides in the second direction and divides the pressure relief space; and the second direction intersects the first direction. The battery cell according to the embodiments of the present application can reduce the risk of offset ejection of high-temperature gas, and improve the reliability of pressure relief of the battery cell.

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 No. 202422812820.2, filed on November 18, 2024, entitled “Battery Cell, Pressure Relief Mechanism, Battery Device and Electrical 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 ejection bias 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 on the valve body. The pair of first grooves extend along a first direction and are spaced apart from each other in a second direction. A pressure relief space is formed between the first grooves, and the size of the pressure relief space along the first direction is larger than the size along the second direction. The second groove connects to the first grooves on both sides along the second direction and separates the pressure relief space. The second direction intersects the first direction.

[0008] In this embodiment, by providing a first groove and a second groove on the valve body, when the internal pressure of the battery cell rises to a threshold, the valve body can separate from the outer casing at the second groove and the first groove and flip open to both sides, thereby allowing 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.

[0009] In some embodiments, the first grooves arranged in pairs are symmetrically arranged relative to the pressure relief space. In the second direction, the two ends of the second groove are respectively connected to the middle of the first groove, so that the valve body can be flipped open from both sides simultaneously.

[0010] In some embodiments, the first groove includes a first groove segment and a second groove segment that are intersecting and connected. The first groove segment extends along a first direction, and the second groove segment is disposed opposite to both ends of the first groove segment along the first direction. In the paired first grooves, the second groove segments of both extend towards each other along a second direction at a certain distance and their ends are spaced apart from each other. This can increase the breakage length of the pressure relief mechanism while reducing the risk of secondary accidents caused by the valve body flying out completely during valve ejection, thereby improving the reliability of the pressure relief mechanism.

[0011] In some embodiments, the pressure relief mechanism further includes a third groove, which is arranged opposite to each other along a first direction. One of the third grooves is connected to one end of a pair of first grooves along a second direction, and the other is connected to the other end of a pair of first grooves along a second direction. The depth of the third groove is less than the depth of the first groove, so that when the valve body is flipped open along both sides, the third groove remains connected. It can serve as a flipping shaft, making it easier for the pressure relief mechanism to flip and reducing the difficulty of flipping.

[0012] In some embodiments, the ratio of the dimension of the third groove along the second direction to the dimension of the pressure relief space along the second direction is 0.1 to 0.5, so as to improve the strength of the connection, reduce the risk of cracking, facilitate valve body flipping, and improve the reliability of pressure relief.

[0013] 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.

[0014] 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.

[0015] In some embodiments, the plurality of sidewalls include a pair of first sidewalls and a pair of second sidewalls, 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 second sidewall, and a second direction is parallel to the arrangement direction of the first sidewall, thereby reducing the risk of the second groove rupturing due to expansion during the charging and discharging of the battery cell and improving the reliability of the pressure relief mechanism.

[0016] In some embodiments, the plurality of sidewalls include a pair of first sidewalls and a pair of second sidewalls, 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 sidewall, and a second direction is parallel to the arrangement direction of the second sidewall, thereby enabling the valve body to shield the high-temperature gas discharged from the pressure relief space, which can play a protective role and reduce the impact of high-temperature gas on adjacent battery cells.

[0017] In some embodiments, the housing includes a pressure relief hole and a protective plate. The pressure relief mechanism is disposed in the pressure relief hole, and the protective plate is disposed on the housing and covers the pressure relief hole. The housing is provided with an exhaust groove that extends to the pressure relief hole and communicates with the pressure relief space. This allows for the detection of leakage at the exhaust groove to determine whether the pressure relief mechanism has substandard welding quality that could lead to electrolyte leakage in the battery.

[0018] In some embodiments, there are multiple venting grooves, some of which are configured to correspond to the first groove and some of which are configured to correspond to the second groove, which enables more reliable detection of the pressure relief mechanism and improves the reliability of the pressure relief mechanism.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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, which facilitates welding the valve body to the housing. Simultaneously, this allows both the valve body and housing to have high melting points, reducing the risk of them melting in the event of thermal runaway.

[0023] 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.

[0024] 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.

[0025] Secondly, embodiments of this application provide a pressure relief mechanism, including a valve body and a first groove and a second groove disposed on the valve body. The paired first grooves extend along a first direction and are spaced apart from each other in a second direction, forming a pressure relief space between the first grooves. The dimension of the pressure relief space along the first direction is larger than its dimension along the second direction. The second groove connects to the first grooves on both sides along the second direction and separates the pressure relief space. The second direction intersects the first direction.

[0026] Thirdly, embodiments of this application provide a battery device including a plurality of battery cells according to the first aspect.

[0027] Fourthly, embodiments of this application provide an electrical device, including the battery device of the third aspect.

[0028] According to an embodiment of this application, a battery cell includes a casing, an electrode assembly, and a pressure relief mechanism. By providing a second groove between paired first grooves, when the internal pressure of the battery cell rises to a threshold, the valve body separates from the casing at the second and first grooves and flips open to both sides, thereby allowing the high-temperature gas inside the battery cell to be ejected in a direction perpendicular to the casing, reducing the risk of high-temperature gas ejection deviation. Furthermore, by making the pressure relief space larger in the first direction than in the second direction, and by extending the second groove in the second direction, the size of the second groove can be reduced, lowering the risk of the second groove cracking before the ejection valve. Simultaneously, after the ejection valve, the flipping lever arm can be increased, making it easier to flip under the same force, thus improving the reliability of the pressure relief mechanism.

[0029] 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

[0030] 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.

[0031] Figure 1 is a schematic diagram of the vehicle structure provided in some embodiments of this application;

[0032] Figure 2 is an exploded schematic diagram of a battery device provided in some embodiments of this application;

[0033] Figure 3 is an exploded view of a single battery cell provided in some embodiments of this application;

[0034] Figure 4 is a front view of a pressure relief mechanism provided in some embodiments of this application;

[0035] Figure 5 is a schematic diagram of the structure of a single battery cell at one angle provided in some embodiments of this application;

[0036] Figure 6 is a structural schematic diagram of a battery cell from another angle provided in some embodiments of this application;

[0037] Figure 7 is a cross-sectional view of a battery cell provided in some embodiments of this application;

[0038] Figure 8 is an enlarged view of point A in Figure 7;

[0039] Figure 9 is a cross-sectional view along the EE direction in Figure 7;

[0040] Figure 10 is an enlarged view of point B in Figure 9;

[0041] Figure 11 is an enlarged view of point C in Figure 7;

[0042] Figure 12 is a bottom view of a battery cell provided in some embodiments of this application.

[0043] The accompanying drawings are not necessarily drawn to scale.

[0044] Marking description: 100 Battery unit, 200 Controller, 300 Motor; 10 Battery cell, 20 Housing; 1 Outer shell, 11 Housing, 111 Bottom wall, 112 First side wall, 113 Second side wall, 12 Cover plate, 13 Pressure relief hole, 14 Protective plate, 15 Exhaust groove, 2 Electrode assembly, 3 Pressure relief mechanism, 31 Valve body, 32 First groove, 32a First sub-groove, 32b Second sub-groove, 321 First groove segment, 322 Second groove segment, 33 Second groove, 34 Third groove; X First direction, Y Second direction, Z Third direction. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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 groove ruptures, causing the valve body to flip open from one side along the groove, creating a pressure relief space. This releases the gas inside the battery, relieving internal pressure and reducing the risk of explosion. However, in actual pressure relief, after the valve body flips open from one side, it also blocks the ejected high-temperature gas from that side. This causes the high-temperature gas and flame from the battery cell to escape to the other side, transferring heat to adjacent battery cells and causing heat diffusion.

[0053] 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 providing a pair of first grooves on the valve body and connecting the two ends of the second groove to the first groove, the valve body can be flipped open from both sides at the same time, reducing the risk of high-temperature gas ejection bias.

[0054] The technical solutions described in the embodiments of this application are applicable to the battery device 100 and electrical devices using the battery device 100.

[0055] 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.

[0056] 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.

[0057] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0058] 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.

[0059] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Please refer to Figures 3 and 4 together. Figure 3 shows an exploded view of a battery cell 10 provided in some embodiments of this application, and Figure 4 shows a front view of a pressure relief mechanism 3 provided in some embodiments of this application.

[0065] 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 on the valve body 31. The paired first grooves 32 extend along a first direction X and are spaced apart from each other in a second direction Y. A pressure relief space is formed between the first grooves 32, and the size of the pressure relief space along the first direction X is larger than the size along the second direction Y. The second groove 33 connects to the first grooves 32 on both sides along the second direction Y, and the second direction Y intersects with the first direction X.

[0066] In this embodiment of the application, the pressure relief mechanism 3 provides a second groove 33 between the paired first grooves 32. When the internal pressure of the battery cell 10 rises to a threshold, the valve body 31 can separate from the outer shell 1 in the second groove 33 and divide into two sub-valve bodies 31. Each sub-valve body 31 flips open from both sides of the pressure relief space along the first groove 32, thereby allowing the high-temperature gas in 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.

[0067] Furthermore, the dimension of the pressure relief space along the first direction X refers to the extension distance of the first groove 32 along the first direction X, and the dimension of the pressure relief space along the second direction Y refers to the spacing between the paired first grooves 32 along the second direction Y.

[0068] By making the size of the pressure relief space along the first direction X larger than the size along the second direction Y, and by extending the second groove 33 along the second direction Y, the size of the second groove 33 can be reduced, thus lowering the risk of the second groove 33 cracking in front of the spray valve. Simultaneously, the distance between the second groove 33 and the flipping shaft can be increased, i.e., the flipping lever arm can be increased, making it easier to flip under the same force. This makes it easier for the valve body 31 to flip open after the spray valve, and also makes the entire pressure relief mechanism 3 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.

[0069] Please refer to Figures 3 to 6. Figures 5 and 6 respectively show schematic diagrams of the structure of the battery cell 10 at different angles provided in some embodiments of this application.

[0070] In some alternative embodiments, the housing 1 includes a housing 11 and a cover plate 12, the housing 11 having an opening, the cover plate 12 being disposed in the opening and connected to the housing 11, and at least one of the housing 11 and the cover plate 12 being provided with a pressure relief mechanism 3.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] In some alternative 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.

[0075] 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.

[0076] Optionally, the battery cell 10 can be a cylindrical battery cell 10, a prismatic battery cell 10, a pouch battery cell 10, or a battery cell 10 of other shapes. The prismatic battery cell 10 includes a square battery cell 10, a blade-shaped battery cell 10, and a multi-prismatic battery, such as a hexagonal prismatic battery.

[0077] In some 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 X is parallel to the arrangement direction of the second sidewalls 113, and a second direction Y is parallel to the arrangement direction of the first sidewalls 112.

[0078] At this time, the first direction X is the length direction of the battery cell 10, and the second direction Y is the width direction of the battery cell 10.

[0079] When the pressure relief mechanism 3 is installed on the bottom wall 111 and / or the cover plate 12, the second groove 33 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 second groove 33 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.

[0080] It is understood that in other embodiments, the multiple sidewalls include a pair of first sidewalls 112 and a pair of second sidewalls 113, the area of ​​the first sidewall 112 is larger than the area of ​​the second sidewall 113, the first direction X is parallel to the arrangement direction of the first sidewalls 112, and the second direction Y is parallel to the arrangement direction of the second sidewalls 113.

[0081] At this time, the first direction X is the width direction of the battery cell 10, and the second direction Y is the length direction of the battery cell 10.

[0082] When the pressure relief mechanism 3 is installed on the bottom wall 111 and / or the cover plate 12, the second groove 33 extends along the length direction of the battery cell 10. Therefore, when the valve body 31 is sprayed, it can be flipped open to both sides along the width direction of the battery cell 10. This allows the valve body 31 to shield the high-temperature gas discharged from the pressure relief space on the first side wall 112, i.e. the large surface side of the battery cell 10, thus providing protection and reducing the impact of high-temperature gas on adjacent battery cells 10.

[0083] Please refer to Figures 3 to 6. The following is a detailed description of the specific structure of the pressure relief mechanism 3, taking the pressure relief mechanism 3 installed on the bottom wall 111 as an example.

[0084] 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 second groove 33 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 second groove 33 and divide into two sub-valve bodies 31. One sub-valve body 31 is opened by flipping through the second groove 33 via one side of the first sub-groove 32a and the second sub-groove 32b, and the other sub-valve body 31 is opened by flipping through the second groove 33 via the other side of the first sub-groove 32a and the second sub-groove 32b. This allows for pressure relief by opening the door from both sides of the pressure relief space, reducing the risk of bias.

[0085] In some alternative embodiments, the first grooves 32 arranged in pairs are symmetrically arranged relative to the pressure relief space, and in the second direction Y, the two ends of the second groove 33 are respectively connected to the middle of the first groove 32.

[0086] The first sub-groove 32a and the second sub-groove 32b are symmetrically arranged relative to the pressure relief space. One end of the second groove 33 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.

[0087] In some alternative implementations, the first groove 32 includes a first groove segment 321 and a second groove segment 322 that are intersecting. The first groove segment 321 extends along a first direction X, and the second groove segment 322 is disposed opposite to the two ends of the first groove segment 321 along the first direction X. In the pair of first grooves 32, the second groove segments 322 of the two extend a certain distance toward each other along a second direction Y and their ends are spaced apart from each other.

[0088] 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.

[0089] 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.

[0090] Please refer to Figures 3 to 10. Figure 7 shows a cross-sectional view of a battery cell 10 provided in some embodiments of this application. Figure 8 shows an enlarged view of point A in Figure 7. Figure 9 shows a cross-sectional view in the EE direction in Figure 7. Figure 10 shows an enlarged view of point B in Figure 9.

[0091] In some alternative embodiments, the ratio of the depth of the first groove 32 to the depth of the second groove 33 is 0.8 to 1.2.

[0092] The depth of the first groove 32 refers to the depth T1 of the indentation from the surface of the valve body 31, and the depth of the second groove 33 refers to the depth T2 of the indentation from the surface of the valve body 31. The ratio of the depth T1 of the first groove 32 to the depth T2 of the second groove 33 is 0.8 to 1.2.

[0093] By ensuring that the ratio of the depth T1 of the first groove 32 to the depth T2 of the second groove 33 is greater than or equal to 0.8, the valve body 31 can smoothly flip open along the first groove 32 after the second groove 33 breaks. Conversely, by ensuring that the ratio of the depth T1 of the first groove 32 to the depth T2 of the second groove 33 is less than or equal to 1.2, the risk of the first groove 32 breaking first can be reduced, thus ensuring that during valve operation, the valve body 31 can reliably break sequentially from the second groove 33 to the first groove 32, achieving the flipping opening of the valve body 31.

[0094] Optionally, the cross-section of the first groove 32 and / or the second groove 33 along its extension direction can be configured as an inverted trapezoid or an inverted triangle, etc. The first groove 32 and / or the second groove 33 can be formed by stamping or CNC machining, which can make the groove walls smoother. By controlling the stamping depth, the burst pressure can be controlled so that when the internal pressure of the battery cell reaches the threshold, the outer casing 1 will preferentially break from the pressure relief mechanism 3, rather than from other parts.

[0095] Optionally, the depth T1 of the first groove 32 is equal to the depth T2 of the second groove 33, to facilitate design and manufacturing.

[0096] Please refer to Figures 3 through 11. Figure 11 shows an enlarged view of point C in Figure 7.

[0097] In some alternative embodiments, the pressure relief mechanism 3 further includes a third groove 34, which is disposed opposite to each other along the first direction X, and one of them is connected to one end of the pair of first grooves 32 along the second direction Y, and the other is connected to the other end of the pair of first grooves 32 along the second direction Y. The depth of the third groove 34 is less than the depth of the first groove 32.

[0098] Specifically, one end of the third groove 34 is connected to one end of the first sub-groove 32a and the second sub-groove 32b, and the other end of the third groove 34 is connected to the other end of the first sub-groove 32a and the second sub-groove 32b, thus forming a pressure relief space by the first groove 32 and the third groove 34 together. By making the depth T3 of the third groove 34 less than the depth T1 of the first groove 32, the third groove 34 remains connected when the valve body 31 is flipped open along both sides, and it can serve as a flipping axis, thereby making it easier for the pressure relief mechanism 3 to flip and reducing the difficulty of flipping.

[0099] Optionally, the third groove 34 can extend along an arc-shaped trajectory, and the first groove 32 and the third groove 34 can enclose each other to form a racetrack-shaped mechanism. Furthermore, when the paired first grooves 32 are symmetrical with respect to the pressure relief space, the paired third grooves 34 can also be symmetrical with respect to the pressure relief space, thereby improving the reliability of the valve body 31 flipping to both sides and further reducing the risk of high-temperature gas ejection deviation.

[0100] In some alternative embodiments, the ratio of the dimension W1 of the third groove 34 along the second direction Y to the dimension W2 of the pressure relief space along the second direction Y is 0.1 to 0.5.

[0101] By making the ratio of the dimension W1 of the third groove 34 along the second direction Y to the dimension W2 of the pressure relief space along the second direction Y greater than or equal to 0.1, the strength of the connection can be improved and the risk of cracking can be reduced when the valve body 31 is flipped open from both sides. Furthermore, by making the ratio of the dimension W1 of the third groove 34 along the second direction Y to the dimension W2 of the pressure relief space along the second direction Y less than or equal to 0.5, the valve body 31 can be easily flipped, improving the reliability of pressure relief.

[0102] Please refer to Figures 3 through 12. Figure 12 shows an enlarged view of point C in Figure 7.

[0103] 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.

[0104] 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.

[0105] 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 second groove 33. By providing multiple exhaust grooves 15 and making the exhaust grooves 15 correspond to the first groove 32 and the second groove 33 respectively, the pressure relief mechanism 3 can be detected more reliably, thereby improving the reliability of the pressure relief mechanism 3.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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 makes it easier to weld the valve body 31 onto the housing 1. At the same time, it also gives the housing 1 and the valve body 31 a high melting point, which can reduce the risk of the housing 1 and the valve body 31 melting in the event of thermal runaway.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] Please refer to Figures 1 to 12. The battery cell 10 provided in this embodiment includes a housing 1, an electrode assembly 2, and a pressure relief mechanism 3. The pressure relief mechanism 3 is disposed on the bottom wall 111 of the housing 1. The pressure relief mechanism 3 includes a valve body 31 and a first groove 32, a second groove 33, and a third groove 34 disposed on the valve body 31. The paired first grooves 32 extend along the first direction X and are spaced apart from each other in the second direction Y. The third groove 34 is connected to both ends of the paired first grooves 32 along the second direction Y and surrounds the first grooves 32 to form a pressure relief space. The size of the pressure relief space along the first direction X is larger than the size along the second direction Y. The second groove 33 extends along the second direction Y and is connected to the middle of the paired first grooves 32.

[0117] In this embodiment, when the internal pressure of the battery cell 10 rises to a threshold, the valve body 31 separates from the outer casing 1 at the second groove 33 and the first groove 32, and uses the third groove 34 as a connecting pivot, causing the valve body 31 to flip open to both sides. This allows 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. Furthermore, by making the size of the pressure relief space along the first direction X larger than the size along the second direction Y, and by extending the second groove 33 along the second direction Y, the size of the second groove 33 can be reduced, lowering the risk of the second groove 33 cracking before the ejection valve. Simultaneously, after the ejection valve, the flipping lever arm can be increased, making it easier to flip under the same force, thus improving the reliability of the pressure relief mechanism 3.

[0118] It should be noted that the pressure relief mechanism disclosed in this application can be used in the battery cell 10 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 the battery cell 10 and electrical devices including the battery device 100, but it is not limited to the battery cell 10. The pressure relief mechanism 3 disclosed in this application can also be used to relieve pressure in other products when the internal pressure exceeds a threshold, thus increasing design freedom and operational flexibility for the product.

[0119] 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 on the housing. The pressure relief mechanism includes a valve body and a first groove and a second groove disposed on the valve body. The pair of first grooves extend along a first direction and are spaced apart from each other in a second direction. A pressure relief space is formed between the first grooves, and the size of the pressure relief space along the first direction is larger than the size along the second direction. The second groove connects to the first grooves on both sides along the second direction and separates the pressure relief space. The second direction intersects with the first direction.

2. The battery cell according to claim 1, wherein, The first grooves, arranged in pairs, are symmetrically arranged relative to the pressure relief space. In the second direction, the two ends of the second groove are respectively connected to the middle of the first groove.

3. The battery cell according to claim 1 or 2, wherein, The first groove includes a first groove segment and a second groove segment connected together. The first groove segment extends along a first direction, and the second groove segment is disposed opposite to both ends of the first groove segment along the first direction. In the paired first grooves, the second groove segments of both extend a certain distance toward each other along the second direction and their ends are spaced apart.

4. The battery cell according to any one of claims 1 to 3, wherein, The pressure relief mechanism also includes a third groove; The third groove is arranged opposite to the first groove along the first direction, and one of them is connected to one end of the pair of first grooves, and the other is connected to the other end of the pair of first grooves. The depth of the third groove is less than the depth of the first groove.

5. The battery cell according to claim 4, wherein, The ratio of the dimension of the third groove along the second direction to the dimension of the pressure relief space along the second direction is 0.1 to 0.

5.

6. The battery cell according to any one of claims 1 to 5, 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.

7. The battery cell according to claim 6, 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.

8. The battery cell according to claim 7, 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 second sidewall, and the second direction is parallel to the arrangement direction of the first sidewall.

9. The battery cell according to claim 7, 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.

10. The battery cell according to any one of claims 1 to 9, wherein, The outer casing includes a pressure relief hole and a protective plate. The pressure relief mechanism is disposed in the pressure relief hole, and the protective plate is disposed on the outer casing and covers the pressure relief hole. The outer casing is provided with an exhaust groove, which extends to the pressure relief hole and communicates with the pressure relief space.

11. The battery cell according to claim 10, wherein, The number of exhaust grooves is multiple, some of which are arranged corresponding to the first groove and some of which are arranged corresponding to the second groove.

12. The battery cell according to any one of claims 1 to 11, wherein, The material of at least a portion of the outer casing includes one of the following: steel, aluminum alloy, and titanium alloy.

13. The battery cell according to claim 12, wherein, The material of at least a portion of the outer casing includes stainless steel or carbon steel.

14. The battery cell according to any one of claims 1 to 13, 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.

15. The battery cell according to any one of claims 1 to 14, 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.

16. The battery cell according to any one of claims 1 to 15, 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.

17. A pressure relief mechanism, comprising a valve body and a first groove and a second groove disposed on the valve body; The first grooves in pairs extend along a first direction and are spaced apart from each other in a second direction, forming a pressure relief space between the first grooves, and the size of the pressure relief space along the first direction is larger than the size along the second direction. The second groove connects to the first grooves on both sides along the second direction and separates the pressure relief space. The second direction intersects the first direction.

18. A battery device comprising a plurality of battery cells according to any one of claims 1-16.

19. An electrical device comprising the battery device as described in claim 18.

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