Battery cell, battery device, power consuming device, and energy storage device

Abstract

The application provides a battery monomer, a battery device, a power consumption device and an energy storage device, and belongs to the technical field of batteries. The battery monomer comprises an electrode assembly, a shell assembly and an explosion-proof valve. The shell assembly is used for accommodating the electrode assembly, and the shell assembly comprises a first shell wall in a rectangular shape, and the first shell wall has a first side and a second side intersecting with each other. The explosion-proof valve is arranged on the first shell wall, and the length direction of the explosion-proof valve intersects with the extension directions of the first side and the second side. In this way, the periodic stress applied to the explosion-proof valve due to the expansion of the electrode assembly can be reduced, so that the cracking problem of the explosion-proof valve under non-design conditions is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, power supply device, and energy storage device. Background Technology

[0002] Energy conservation and emission reduction are crucial for sustainable social development. Batteries, with their ability to store or release energy as needed, are widely used in various electrical devices and energy storage systems, and are an important component in promoting energy transition and sustainable development. For the new energy industry, battery technology is a critical factor in its development.

[0003] During the use of a battery cell, the battery cell will shrink or expand in volume due to cycling, which will cause the explosion-proof valve to crack under non-design conditions due to the shrinkage and expansion of the battery cell volume. Utility Model Content

[0004] This application aims to at least solve one of the technical problems existing in the background art. To this end, one object of this application is to provide a battery cell, battery device, power supply device, and energy storage device that can improve the cracking problem of explosion-proof valves under non-design conditions.

[0005] An embodiment of the first aspect of this application provides a battery cell including an electrode assembly, a housing assembly, and an explosion-proof valve. The housing assembly is used to house the electrode assembly and includes a rectangular first housing wall having intersecting first and second sides. The explosion-proof valve is disposed on the first housing wall, and the longitudinal direction of the explosion-proof valve intersects the extending directions of the first and second sides.

[0006] In the technical solution of this application embodiment, by making the outer shell assembly accommodating the electrode assembly include a rectangular first shell wall, the first shell wall having an intersecting first side and a second side, an explosion-proof valve is disposed on the first shell wall, and the length direction of the explosion-proof valve intersects with the extension direction of the first side and the second side, so as to reduce the periodic stress applied to the explosion-proof valve due to the expansion of the electrode assembly, thereby improving the cracking problem of the explosion-proof valve under non-design conditions.

[0007] In some embodiments, the dimension of the first side is larger than the dimension of the second side, and the acute angle formed between the first side and the extension line extending along the length direction of the explosion-proof valve is a first included angle. The first included angle is greater than 0° and less than or equal to 45°. This reduces the expansion stress on the explosion-proof valve and improves the cracking problem of the explosion-proof valve under non-design conditions.

[0008] In some embodiments, the explosion-proof valve includes a weak portion. A first shell wall has a first region and a second region that are evenly divided and connected along the extension direction of a second side, with the first side located in the first region. The weak portion located in the first region includes a connected first part and a second part. Specifically, along the thickness direction of the first shell wall, the thickness of the first part is less than or equal to the thickness of the second part; along the extension direction of the second side, the shortest distance from the second part to the first side is less than the shortest distance from the first part to the first side. This improves the stress-bearing capacity of the second part of the explosion-proof valve near the first side, thereby further improving the cracking problem of the explosion-proof valve under non-design conditions.

[0009] In some embodiments, along the extending direction of the second side, the shortest distance between the second portion and the first side is greater than or equal to 3 mm. This avoids the periodic stress caused by the expansion of the electrode assembly from directly acting on the weak part, reducing the impact of the periodic stress caused by the expansion of the electrode assembly on the explosion-proof valve, and improving the cracking problem of the explosion-proof valve under non-design conditions.

[0010] In some embodiments, along the extending direction of the second side, the ratio of the distance from any point in the second portion to the first side to the distance from the second side is greater than 0 and less than or equal to 0.2. This allows the explosion-proof valve to have better structural strength in areas significantly affected by periodic stresses caused by the expansion of the electrode assembly, thus helping to improve the cracking problem of the explosion-proof valve under non-design conditions.

[0011] In some embodiments, along the extending direction of the second side, the distance from any point in the second part to the first side is less than or equal to the distance from any point in the first part to the first side. This balances the expansion stress on the points connected to both sides of the point in the second part that is closest to the first side. Furthermore, this makes the boundary line between the second and first parts parallel to the first side, allowing for convenient determination of the boundary between the second and first parts based on the first side during the manufacture of the explosion-proof valve, thus facilitating the manufacturing of both parts.

[0012] In some embodiments, the thickness of the second portion along the thickness direction of the first shell wall gradually decreases as the distance from the first side increases. This improves the cracking problem of the explosion-proof valve under non-design conditions while facilitating the pressure relief function of the explosion-proof valve.

[0013] In some embodiments, the weak portion located in the second region includes a connected third and fourth portion. The third and first portions are centrally symmetrical about the centroid of the first shell wall, and the fourth and second portions are centrally symmetrical about the centroid of the first shell wall. This allows for the improvement of cracking issues in explosion-proof valves under non-design conditions while simplifying the valve's structure and balancing stress distribution.

[0014] In some embodiments, the first shell wall further includes a third side parallel to and opposite to the first side, and the weak portion located in the second region includes a connected third part and a fourth part. Specifically, along the thickness direction of the first shell wall, the thickness of the third part is less than or equal to the thickness of the fourth part; along the extension direction of the second side, the shortest distance of the fourth part from the third side is less than the shortest distance of the third part from the third side. This improves the stress-bearing capacity of the fourth part of the explosion-proof valve near the third side, thereby mitigating the cracking problem of the explosion-proof valve under non-design conditions.

[0015] In some embodiments, the shortest distance from the fourth part to the third side is equal to the shortest distance from the second part to the first side. This ensures that the explosion-proof valve is equidistant from the first and third sides, thereby balancing the expansion stress on the explosion-proof valve.

[0016] In some embodiments, along the thickness direction of the first shell wall, the thickness of the fourth portion at the shortest distance from the third side is equal to the thickness of the second portion at the shortest distance from the first side. This allows for a uniform stress distribution on both sides of the explosion-proof valve.

[0017] In some embodiments, the first shell wall includes a mounting hole. The explosion-proof valve also includes a connecting portion and a body portion. The connecting portion is used to connect to the wall of the mounting hole, and a weak portion is located between the connecting portion and the body portion, and the weak portion is disposed around the body portion. Along the thickness direction of the first shell wall, the thickness of both the body portion and the connecting portion is greater than the thickness of the weak portion. This strengthens the structural strength of the body portion and the connecting portion, reducing the degree of bulging or denting deformation of the body portion, thereby reducing the alternating stress borne by the weak portion and improving the safety and stability of the battery.

[0018] In some embodiments, the weak portion is formed by providing a groove in the first shell wall. This helps to reduce processing costs and processing difficulty.

[0019] In some embodiments, the housing assembly includes a housing and an end cap. The housing includes a receiving cavity for accommodating an electrode assembly and an opening communicating with the receiving cavity, the end cap closing onto the opening. A first housing wall is one wall of the housing. This reduces the likelihood of the explosion-proof valve cracking under non-design conditions when the housing includes a first housing wall.

[0020] An embodiment of the second aspect of this application provides a battery device that includes the battery cell described in the above embodiments.

[0021] An embodiment of the third aspect of this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0022] An embodiment of the fourth aspect of this application provides an energy storage device, which includes the battery device described in the above embodiments, the battery device being used to store electrical energy.

[0023] 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

[0024] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0025] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0026] Figure 2 This is an exploded view of the battery device according to some embodiments of this application;

[0027] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0028] Figure 4 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0029] Figure 5 This is a schematic diagram of the structure of the first shell wall and the explosion-proof valve in some embodiments of this application;

[0030] Figure 6 For this application Figure 5 A sectional view of line A-A' in the diagram;

[0031] Figure 7 This is a schematic diagram of the structure of the first shell wall and the explosion-proof valve in some embodiments of this application;

[0032] Figure 8 This is a schematic diagram of the structure of the first shell wall and the explosion-proof valve in some embodiments of this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1000 vehicles;

[0035] Battery unit 100, controller 200, motor 300;

[0036] Box 10, first component 11, second component 12;

[0037] Battery cell 20, electrode assembly 21, tab 211, outer casing assembly 22, casing 22A, end cap 22B, first casing wall 221, first side 221A, second side 221B, third side 221C, mounting hole 221D, first zone 2211, second zone 2212, electrode terminal 222; explosion-proof valve 23, weak part 231, first part 2311, second part 2312, third part 2313, fourth part 2314, connecting part 232, body part 233. Detailed Implementation

[0038] 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.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0040] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0043] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0044] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0045] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0046] Currently, the application of rechargeable batteries is becoming increasingly widespread, judging from market trends. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in various electronic devices, such as electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application areas of rechargeable batteries continue to expand, the market demand is also constantly increasing.

[0047] During the charge-discharge cycle of a single battery cell, the insertion or extraction of ions by the positive and negative active materials, as well as the accumulation thickness of side reactions in the electrode assembly system, can cause the volume of the electrode assembly to shrink or expand, affecting the battery's performance and lifespan.

[0048] For example, during the charge-discharge cycle of a battery cell, the electrode plates of the electrode assembly expand in volume due to the cycle, causing a change in the volume of the electrode assembly. This volume change is transmitted to the battery cell casing, subjecting the casing to periodic stress, which in turn causes the explosion-proof valve installed on the casing to be subjected to stress and crack under non-design conditions.

[0049] To improve the cracking problem of explosion-proof valves under non-design conditions, this application provides a battery cell, a battery device, an electrical device, and an energy storage device. The battery cell includes an electrode assembly, a housing assembly, and an explosion-proof valve. The housing assembly houses the electrode assembly and includes a rectangular first housing wall with intersecting first and second sides. The explosion-proof valve is disposed on the first housing wall, and the longitudinal direction of the explosion-proof valve intersects with the extending directions of the first and second sides. This reduces the periodic stress applied to the explosion-proof valve due to the expansion of the electrode assembly, thereby improving the cracking problem of the explosion-proof valve under non-design conditions.

[0050] The battery cells and battery devices disclosed in this application can be used, but are not limited to, in electrical devices or energy storage devices such as vehicles, ships, or aircraft. A power system comprising the electrical device or energy storage device can be constructed using the battery cells and battery devices disclosed in this application. This helps to improve the cracking problem of explosion-proof valves under non-design conditions and enhances the stability and lifespan of the battery cells.

[0051] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0052] This application also provides an energy storage device that uses a battery as a power source. The energy storage device can be, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system.

[0053] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0054] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0055] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0056] Please refer to Figure 2 , Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application. The battery device 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first component 11 and a second component 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second component 12 may be a hollow structure with one open end, and the first component 11 may be a plate-like structure, covering the open side of the second component 12 so that the first component 11 and the second component 12 jointly define the space. Alternatively, the first component 11 and the second component 12 may both be hollow structures with one open side, with the open side of the first component 11 covering the open side of the second component 12. Of course, the housing 10 formed by the first component 11 and the second component 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0057] In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel connections. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the housing 10. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0058] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0059] Please refer to Figures 3-4 , Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application. Figure 4 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application.

[0060] This application provides a battery cell 20, which includes an electrode assembly 21, a housing assembly 22, and an explosion-proof valve 23. The housing assembly 22 is used to house the electrode assembly 21, and includes a rectangular first housing wall 221 with intersecting first side 221A and second side 221B. The explosion-proof valve 23 is disposed on the first housing wall 221, and the length direction of the explosion-proof valve 23 intersects the extension directions of the first side 221A and the second side 221B.

[0061] Battery cell 20 refers to the smallest unit that makes up a battery.

[0062] The housing assembly 22 is a component for housing the electrode assembly 21. The housing space formed by the housing assembly 22 can also be used to house electrolyte and other components. The housing assembly 22 includes a first housing wall 221, wherein the orthographic projection of the first housing wall 221 in a projection plane parallel to the first housing wall 221 can be a rectangle, a square, or a parallelogram, etc. The first housing wall 221 has a first side 221A and a second side 221B that are connected, and the extension direction of the first side 221A intersects the extension direction of the second side 221B. That is, the first side 221A extends along a first direction X, the second side 221B extends along a second direction Y, and the first direction X and the second direction Y intersect. In some embodiments, the first direction X and the second direction Y intersect perpendicularly.

[0063] Understandably, to form a receiving space for the electrode assembly 21, the housing assembly 22 may include multiple contiguous walls, one of which serves as the first housing wall 221. The housing assembly 22 also includes electrode terminals 222. The housing assembly 22 can have various shapes and sizes. For example, the housing assembly 22 may be cuboid, cylindrical, hexagonal prism, etc. The shape of the housing assembly 22 can be determined based on the specific shape and size of the electrode assembly 21. The housing assembly 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0064] Electrode assembly 21 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 21. Electrode assembly 21 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 21, while the portions of the positive and negative electrode sheets without active material each constitute a tab 211. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 211 connect to the electrode terminals to form a current loop.

[0065] The explosion-proof valve 23 is a pressure relief mechanism used to release internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The explosion-proof valve 23 being disposed on the first housing wall 221 can mean that the explosion-proof valve 23 is installed on the first housing wall 221, for example, by welding it into a mounting hole opened in the first housing 221; or it can mean that the explosion-proof valve 23 is formed on the first housing wall 221 by reducing the thickness of a local area of ​​the first housing wall 221, and can be an integrated explosion-proof valve 23 that can break open when the internal pressure of the battery cell 20 reaches the threshold.

[0066] The explosion-proof valve 23 can be set as a rectangle or a racetrack shape. The length direction of the explosion-proof valve 23 is the extension direction of the long side of the explosion-proof valve, such as the direction of the long side of the rectangular explosion-proof valve or the direction of the straight segment of the racetrack-shaped explosion-proof valve. The length direction of the explosion-proof valve 23 extends along the third direction Z. The third direction Z intersects with the first direction X and the second direction Y. In this way, the extension direction of the long side of the explosion-proof valve 23 is inclined to the first side 221A.

[0067] In some embodiments, the third direction Z is parallel to the extension direction of the first side 221A, so that a longer portion (i.e., the long side) of the weak part of the explosion-proof valve 23 is close to and parallel to the first side 221A. When the battery cell 20 expands in volume during charge and discharge cycles, it will squeeze the shell wall connected to the first side 221A outward, which will cause the explosion-proof valve 23 disposed on the first shell wall 221 to be subjected to tearing force in the planar direction, causing the weak part of the explosion-proof valve 23 to crack under non-design conditions. Therefore, in order to improve the cracking of the explosion-proof valve 23 under non-design conditions, the length direction of the explosion-proof valve 23 can be set to be inclined to the extension direction of the first side 221A and the second side 221B, so as to decompose the periodic stress F applied to the explosion-proof valve 23 due to the expansion of the electrode assembly 21 during the cycle. When the length direction of the explosion-proof valve 23 is set to be inclined to the extension direction of the first side 221A and the second side 221B, the periodic stress applied to the explosion-proof valve 23 due to the expansion of the electrode assembly 21 changes from F to F1, and F1 < F. Therefore, setting the length direction of the explosion-proof valve 23 to be inclined to the extension direction of the first side 221A and the second side 221B can reduce the periodic stress applied to the explosion-proof valve 23 due to the expansion of the electrode assembly 21, thereby improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0068] In the technical solution of this application embodiment, by making the outer shell assembly 22 that houses the electrode assembly 21 include a rectangular first shell wall 221, the first shell wall 221 having intersecting first side 221A and second side 221B, the explosion-proof valve 23 is disposed on the first shell wall 221, and the length direction of the explosion-proof valve 23 intersects with the extension direction of the first side 221A and the second side 221B, so as to disperse the periodic stress applied to the explosion-proof valve 23 due to the expansion of the electrode assembly 21, avoid stress concentration in a single direction, thereby improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0069] According to some embodiments of this application, the size of the first side 221A is larger than the size of the second side 221B, and the acute angle formed between the first side 221A and the extension line L1 extending along the length direction of the explosion-proof valve 23 is a first included angle α. The first included angle α is greater than 0° and less than or equal to 45°.

[0070] In some embodiments, the first included angle α is greater than 0° and less than 90°. For example, in some embodiments, the first included angle α is equal to 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80° or 85°.

[0071] To allow the explosion-proof valve 23 to be mounted on the first shell wall 221, with a fixed size for the explosion-proof valve 23, the smaller the size of the second side 221B, the smaller the variable range of the first included angle α. Conversely, the larger the size of the second side 221B, the larger the variable range of the first included angle α. A larger first included angle α results in a smaller acute angle formed by the extension line L1 of the explosion-proof valve 23 along its length and the second side 221B, bringing the explosion-proof valve 23 closer to the first side 221A, and making it easier for the periodic stress caused by the expansion of the electrode assembly 21 to act on the explosion-proof valve 23. Conversely, a smaller first included angle α results in a larger acute angle formed by the extension line L1 of the explosion-proof valve 23 along its length and the second side 221B, bringing the explosion-proof valve 23 farther from the first side 221A, and reducing the impact of the periodic stress caused by the expansion of the electrode assembly 21 on the explosion-proof valve 23. Therefore, the first included angle α can be set to be less than or equal to 45°.

[0072] When the length direction of the explosion-proof valve 23 is set to be inclined to the extension direction of the first side 221A and the second side 221B, the periodic stress applied to the explosion-proof valve 23 by the expansion of the electrode assembly 21 changes from F to F1, where F1 = cosαF. Therefore, the periodic stress applied to the explosion-proof valve 23 due to the expansion of the electrode assembly 21 is reduced, thereby improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0073] It should be noted that the range of the first angle α can be determined based on the simulation experiment of the deformation direction of the first shell wall 221 and the stress distribution of the weak part of the explosion-proof valve 23.

[0074] By setting the first included angle α to be greater than 0° and less than or equal to 45°, the expansion stress on the explosion-proof valve 23 can be reduced, thus improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0075] Please continue reading. Figures 4-8 , Figure 5 This is a schematic diagram of the structure of the first shell wall and the explosion-proof valve in some embodiments of this application. Figure 6 For this application Figure 5 The sectional view of A-A' in the diagram. Figure 7 This is a schematic diagram of the structure of the first shell wall and the explosion-proof valve in some embodiments of this application. Figure 8 This is a schematic diagram of the structure of the first shell wall and the explosion-proof valve in some embodiments of this application.

[0076] According to some embodiments of this application, the explosion-proof valve 23 includes a weak portion 231. A first shell wall 221 has a first region 2211 and a second region 2212 that are evenly divided and connected along the extending direction of a second side 221B. The first side 221A is located in the first region 2211. The portion of the weak portion 231 located in the first region 2211 includes the connected first portion 2311 and second portion 2312. Specifically, along the thickness direction of the first shell wall 221, the thickness of the first portion 2311 is less than or equal to the thickness of the second portion 2312; along the extending direction of the second side 221B, the shortest distance D1 between the second portion 2312 and the first side 221A is less than the shortest distance D2 between the first portion 2311 and the first side 221A.

[0077] The weak point 231 is a relatively weak area in the structure of the explosion-proof valve 23, such as a thinned groove. When the internal pressure or temperature of the battery cell 20 reaches a threshold, the weak point 231 is destroyed by the pressure inside the battery cell 20 to release the pressure.

[0078] The first shell wall 221 having a first region 2211 and a second region 2212 that are equally divided and connected along the extension direction of the second side 221B means that the first shell wall 221 has a first region 2211 and a second region 2212, and along the extension direction of the second side 221B, the size of the first region 2211 is equal to the size of the second region 2212.

[0079] The weak portion 231 includes a portion located in the first region 2211 and a portion located in the second region 2212. The weak portion 231 located in the first region 2211 and the weak portion 231 located in the second region 2212 can be connected.

[0080] The weak portion 231 located in the first region 2211 includes a connected first portion 2311 and a second portion 2312. The phrase "the thickness of the first portion 2311 is less than or equal to the thickness of the second portion 2312" means that, along the thickness direction of the first shell wall 221, the thickness of the first portion 2311 can be less than or equal to the thickness of the second portion 2312. In some embodiments, at least a portion of the thickness of the first portion 2311 may be less than the thickness of the second portion 2312, while the thickness of another portion of the first portion 2311 may be equal to the thickness of the second portion 2312. The phrase "the shortest distance D1 of the second portion 2312 from the first side 221A is less than the shortest distance D2 of the first portion 2311 from the first side 221A" means that the minimum distance from all points in the first portion 2311 to the first side 221A is less than the minimum distance from all points in the second portion 2312 to the first side 221A. If the distance from any point in the first part 2311 to the first side 221A is m1, then the range of values ​​for m1 is [m1...]. min m1 max In the second part 2312, the distance from any point to the first side 221A is n1, and the range of n1 is [n1...]. min n1 max ], where n1 min <m1 min n1 min That is, corresponding to D1, m1 min That is, it corresponds to D2.

[0081] In other words, the point of the weak part 231 located in the first region 2211 that is closest to the first side 221A is located in the second part 2312, and the thickness of the first part 2311 is less than the thickness of the second part 2312.

[0082] In some embodiments, the boundary line between the second portion 2312 and the first portion 2311 may intersect with the extension direction of the first side 221A.

[0083] To prevent the periodic stress caused by the expansion of the electrode assembly 21 from directly acting on the explosion-proof valve 23, a certain distance needs to be maintained between the explosion-proof valve 23 and the first side 221A. However, the closer the explosion-proof valve 23 is to the first side 221A, the more significant the effect of the periodic stress on the explosion-proof valve 23. Therefore, the portion of the explosion-proof valve 23 closest to the first side 221A can have a larger thickness to improve the stress-bearing capacity of the second portion 2312 of the explosion-proof valve 23 closest to the first side 221A, thereby improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0084] It should be noted that the thickness change between the first part 2311 and the second part 2312 can be gradual or abrupt.

[0085] By positioning the first side 221A within the first region 2211, the explosion-proof valve 23 includes a weak portion 231, and the portion of the weak portion 231 located within the first region 2211 comprises a connected first part 2311 and a second part 2312. Along the thickness direction of the first shell wall 221, the thickness of the first part 2311 is less than or equal to the thickness of the second part 2312; along the extension direction of the second side 221B, the shortest distance D1 between the second part 2312 and the first side 221A is less than the shortest distance D2 between the first part 2311 and the first side 221A, thereby improving the stress-bearing capacity of the second part 2312 of the explosion-proof valve 23 near the first side 221A, and further improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0086] According to some embodiments of this application, along the extension direction of the second side 221B, the shortest distance D1 of the second portion 2312 from the first side 221A is greater than or equal to 3 mm.

[0087] In some embodiments, along the extending direction of the second side 221B, the shortest distance D1 from the second portion 2312 to the first side 221A is equal to 3 mm, 4 mm or 5 mm.

[0088] The closer the second part 2312 is to the first side 221A, the greater the impact of the periodic stress caused by the expansion of the electrode assembly 21 on the stress of the explosion-proof valve 23. Therefore, in order to reduce the impact of the periodic stress caused by the expansion of the electrode assembly 21 on the explosion-proof valve 23, the shortest distance D1 of the second part 2312 from the first side 221A along the extension direction of the second side 221B can be greater than or equal to 3 mm.

[0089] Understandably, the shortest distance D1 between the second part 2312 and the first side 221A can be determined by comprehensively considering factors such as the size of the first shell wall 221, the size of the explosion-proof valve 23, the first angle α of the inclination of the explosion-proof valve 23 relative to the first side 221A and the second side 221B, and the material system of the electrode assembly 21.

[0090] In some embodiments, along the extending direction of the second side 221B, the shortest distance D2 of the first portion 2311 from the first side 221A is greater than or equal to 5 mm.

[0091] By extending along the second side 221B, the shortest distance D1 between the second part 2312 and the first side 221A is greater than or equal to 3 mm, so as to avoid the periodic stress caused by the expansion of the electrode assembly 21 acting directly on the weak part 231, reduce the impact of the periodic stress caused by the expansion of the electrode assembly 21 on the explosion-proof valve 23, and improve the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0092] Please continue reading. Figures 5-8 According to some embodiments of this application, along the extension direction of the second side 221B, the ratio of the distance from any point in the second part 2312 to the distance from the first side 221A to the distance from the second side 221B is greater than 0 and less than or equal to 0.2.

[0093] Please continue reading. Figures 7-8 Along the extension direction of the second side 221B (i.e., along the second direction Y), the ratio of the distance from any point in the second part 2312 to the distance from the first side 221A to the distance from the second side 221B is greater than 0 and less than or equal to 0.2. This means that the second part 2312 is provided in the portion between the second auxiliary line Lb parallel to the first side 221A and located at 20% of the distance from the first side 221A to the second side 221B along the second direction Y.

[0094] In some embodiments, a second portion 2312 is provided along the second direction Y, with the first side 221A as a reference, between a first auxiliary line La parallel to the first side 221A corresponding to 10% of the dimension of the second side 221B, and a second auxiliary line Lb parallel to the first side 221A corresponding to 20% of the dimension of the second side 221B. In some embodiments, along the extending direction of the second side 221B, the ratio of the dimension of the first side 221A to the dimension of the second side 221B at any point in the second portion 2312 is equal to 0.1, 0.15, or 0.2.

[0095] In some embodiments, along the extending direction of the second side 221B, the ratio of the shortest distance of the second portion 2312 from the first side 221A to the size of the second side 221B is equal to 0.1, and the ratio of the longest distance of the second portion 2312 from the first side 221A to the size of the second side 221B is equal to 0.2.

[0096] Understandably, from the boundary between the first region 2211 and the second region 2212 towards the first side 221A, the influence of the periodic stress caused by the expansion of the electrode assembly 21 on the explosion-proof valve 23 gradually decreases. Therefore, along the extension direction of the second side 221B, the ratio of the distance from any point in the second part 2312 to the distance from the first side 221A to the distance from the second side 221B is greater than or equal to 0.1 and less than or equal to 0.2. This allows the explosion-proof valve 23 to have better structural strength in areas where it is significantly affected by the periodic stress caused by the expansion of the electrode assembly 21.

[0097] By ensuring that the ratio of the distance from any point in the second part 2312 to the distance from the first side 221A to the distance from the second side 221B along the extension direction of the second side 221B is greater than 0 and less than or equal to 0.2, the explosion-proof valve 23 can have better structural strength in areas where it is greatly affected by the periodic stress caused by the expansion of the electrode assembly 21, which is beneficial to improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0098] Please continue reading. Figures 7-8 According to some embodiments of this application, along the extension direction of the second side 221B, the distance from any point in the second part 2312 to the first side 221A is less than or equal to the distance from any point in the first part 2311 to the first side 221A.

[0099] Along the extension direction of the second side 221B (i.e., along the second direction Y), the dimension of any point in the second part 2312 from the first side 221A is less than or equal to the dimension of any point in the first part 2311 from the first side 221A. This means that an auxiliary line passing through a point in the first part 2311 that has the shortest distance D2 from the first side 221A and is parallel to the first side 221A (such as...) Figures 7-8 The second auxiliary line Lb is provided, and a second part 2312 is provided between the auxiliary line and the first side 221A. A first part 2311 is provided between the auxiliary line and the second area 2212. That is, the dividing line between the second part 2312 and the first part 2311 is parallel to the first side 221A.

[0100] Along the extension direction of the second side 221B, at least two points connected on the auxiliary line parallel to the first side 221A in the second part 2312 experience similar expansion stresses. Therefore, the boundary line between the second part 2312 and the first part 2311 is parallel to the first side 221A, such that the periodic stress caused by the expansion of the electrode assembly 21 at each point in the second part 2312 is greater than the periodic stress caused by the expansion of the electrode assembly 21 at each point in the first part 2311.

[0101] By ensuring that the distance from any point in the second part 2312 to the first side 221A is less than or equal to the distance from any point in the first part 2311 to the first side 221A along the extension direction of the second side 221B, the expansion stress on the points connected to both sides of the point in the second part 2312 that is closest to the first side 221A can be balanced. Furthermore, this makes the boundary line between the second part 2312 and the first part 2311 parallel to the first side 221A. When manufacturing the explosion-proof valve 23, the boundary between the second part 2312 and the first part 2311 can be easily determined based on the first side 221A, facilitating the manufacturing of the second part 2312 and the first part 2311.

[0102] According to some embodiments of this application, the thickness of the second portion 2312 along the thickness direction of the first shell wall 221 gradually decreases as the distance from the first side 221A increases.

[0103] The phrase "the thickness of the second part 2312 gradually decreases along the thickness direction of the first shell wall 221 as the distance from the first side 221A increases" means that the thickness of the point in the second part 2312 that is farther from the first side 221A is less than the thickness of the point in the second part 2312 that is closer to the first side 221A.

[0104] In some embodiments, the point in the second part 2312 with the shortest distance from the first side 221A experiences greater expansion stress than the point in the second part 2312 with the longest distance from the first side 221A. The thickness of the point in the second part 2312 with the shortest distance from the first side 221A is greater than the thickness of the other points in the second part 2312, while the thickness of the point in the second part 2312 with the longest distance from the first side 221A is less than the thickness of the other points in the second part 2312. This thickness is set according to the actual expansion stress experienced at various points in the second part 2312, which is beneficial for improving the cracking problem of the explosion-proof valve 23 under non-design conditions while also ensuring the pressure relief function of the explosion-proof valve 23.

[0105] The thicker the second part 2312, the stronger its resistance to expansion stress; however, excessive thickness is detrimental to the pressure relief function of the explosion-proof valve 23. Therefore, in order to improve the cracking problem of the explosion-proof valve 23 under non-design conditions while facilitating its pressure relief function, the thickness of the second part 2312 along the thickness direction of the first shell wall 221 gradually decreases as the distance from the first side 221A increases.

[0106] The thickness of the second part 2312 can be determined comprehensively based on factors such as the first included angle, the material system of the electrode assembly 21, the size of the explosion-proof valve 23, and the size of the first shell wall 221.

[0107] Similarly, the thickness of the first part 2311, which is located between the boundary line of the first part 2311 and the boundary line of the first region 2211 and the second region 2212, gradually decreases as the distance from the first side 221A increases.

[0108] It should be noted that, in some embodiments, the thickness of the second portion 2312 may be equal at all points to simplify the manufacturing process of the explosion-proof valve 23. In some embodiments, the thickness of the first portion 2311 may also be equal at all points to simplify the manufacturing process of the explosion-proof valve 23.

[0109] By making the thickness of the second part 2312 along the thickness direction of the first shell wall 221 gradually decrease as the distance from the first side 221A increases, the cracking problem of the explosion-proof valve 23 under non-design conditions is improved, while the explosion-proof valve 23 can realize the pressure relief function.

[0110] According to some embodiments of this application, the weak portion 231 located in the second region 2212 includes a connected third portion 2313 and a fourth portion 2314. The third portion 2313 and the first portion 2311 are centrally symmetrical about the centroid of the first shell wall 221, and the fourth portion 2314 and the second portion 2312 are centrally symmetrical about the centroid of the first shell wall 221.

[0111] The point where the boundary line between the first zone 2211 and the second zone 2212 intersects with the auxiliary line that bisects the first side 221 corresponds to the centroid of the first shell wall 221.

[0112] In some embodiments, the third portion 2313 of the second region 2212 may extend into the first region 2211 to connect with the second portion 2312; the first portion 2311 of the first region 2211 may extend into the second region 2211 to connect with the first portion 2311, such as... Figure 5 As shown. In some embodiments, the third portion 2313 is connected to the first portion 2311, as... Figures 7-8 As shown.

[0113] The fact that the third part 2313 and the first part 2311 are centrally symmetrical about the centroid of the first shell wall 221 can mean that the third part 2313 and the first part 2311 can have the same shape, or the same thickness or a variation in thickness. Similarly, the fact that the fourth part 2314 and the second part 2312 are centrally symmetrical about the centroid of the first shell wall 221 can mean that the fourth part 2314 and the second part 2312 can have the same shape, or the same thickness or a variation in thickness.

[0114] By making the weak part 231 located in the second region 2212 include the connected third part 2313 and fourth part 2314, and the third part 2313 and the first part 2311 are centrally symmetrical about the centroid of the first shell wall 221, and the fourth part 2314 and the second part 2312 are centrally symmetrical about the centroid of the first shell wall 221, the cracking problem of the explosion-proof valve 23 under non-design conditions is improved, while the structure of the explosion-proof valve 23 is simplified and the stress distribution on the explosion-proof valve 23 is balanced.

[0115] Please continue reading. Figures 4-8 According to some embodiments of this application, the first shell wall 221 further includes a third side 221C that is parallel to and opposite to the first side 221A. The weak portion 231 located in the second region 2212 includes a connected third portion 2313 and a fourth portion 2314. Specifically, along the thickness direction of the first shell wall 221, the thickness of the third portion 2313 is less than or equal to the thickness of the fourth portion 2314; along the extension direction of the second side 221B, the shortest distance of the fourth portion 2314 from the third side 221C is less than the shortest distance of the third portion 2313 from the third side 221C.

[0116] In some embodiments, the second region 2212 includes a third side 221C. Along the extending direction of the second side 221B, the distance between the portion of the weak portion 231 located in the second region 2212 and the third side 221C is less than the distance between the portion of the weak portion 231 located in the first region 2211 and the third side 221C.

[0117] Along the thickness direction of the first shell wall 221, the thickness of the third part 2313 being less than or equal to the thickness of the fourth part 2314 means that along the thickness direction of the first shell wall 221, the thickness of the third part 2313 can be less than or equal to the thickness of the fourth part 2314. In some embodiments, at least a portion of the thickness of the third part 2313 may be less than the thickness of the fourth part 2314, while the thickness of another portion of the third part 2313 may be equal to the thickness of the fourth part 2314. Along the extension direction of the second side 221B, the shortest distance from the fourth part 2314 to the third side 221C being less than the shortest distance from the third part 2313 to the third side 221C means that the minimum distance among all points in the fourth part 2314 to the third side 221C is less than the minimum distance among all points in the third part 2313 to the third side 221C. For example, if the distance from any point in the third part 2313 to the third side 221C is p1, and the value of p1 is in the range [p1...]. min p1 max In Part 4, 2314, the distance from any point to the third side 221C is q1, and the range of q1 is [q1...]. min , q1 max ]. Among them, q1min <p1 min ;q1 min That is, the shortest distance from the fourth part 2314 to the third side 221C, p1 min That is, the shortest distance from the third part 2313 to the third side 221C.

[0118] It should be noted that the fourth part 2314 may have a portion whose distance from the third side 221C is equal to the distance from the third part 2313 to the third side 221C. In some embodiments, the boundary line between the fourth part 2314 and the third part 2313 may intersect with the extension direction of the third side 221C.

[0119] To prevent the periodic stress caused by the expansion of the electrode assembly 21 from directly acting on the explosion-proof valve 23, a certain distance needs to be maintained between the explosion-proof valve 23 and the third side 221C. However, the closer the explosion-proof valve 23 is to the third side 221C, the more significant the effect of the periodic stress on the explosion-proof valve 23. Therefore, the portion of the explosion-proof valve 23 near the third side 221C can have a larger thickness to improve the stress-bearing capacity of the fourth portion 2314 of the explosion-proof valve 23 near the third side 221C, thereby improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0120] In some embodiments, the first shell wall 221 has a fourth side that is parallel to and opposite to the second side 221B, and the first side 221A, the second side 221B, the third side 221C and the fourth side are connected end to end.

[0121] In some embodiments, the ratio of the distance from any point in the fourth part 2314 to the distance from the third side 221C to the distance from the second side 221B is greater than 0 and less than or equal to 0.2, so as to give the explosion-proof valve 23 better structural strength in the area that is greatly affected by the periodic stress caused by the expansion of the electrode assembly 21.

[0122] By making the weak part 231 located in the second region 2212 include the connected third part 2313 and fourth part 2314. Furthermore, along the thickness direction of the first shell wall 221, the thickness of the third part 2313 is less than or equal to the thickness of the fourth part 2314; along the extension direction of the second side 221B, the shortest distance of the fourth part 2314 from the third side 221C is less than the shortest distance of the third part 2313 from the third side 221C, thereby improving the stress resistance of the fourth part 2314 of the explosion-proof valve 23 near the third side 221C, and thus improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0123] According to some embodiments of this application, the shortest distance from the fourth part 2314 to the third side 221C is equal to the shortest distance from the second part 2312 to the first side 221A.

[0124] The shortest distance from the fourth part 2314 to the third side 221C is equal to the shortest distance from the second part 2312 to the first side 221A, which refers to the extension direction along the second side 221B. The shortest distance from the fourth part 2314 to the third side 221C is equal to the shortest distance from the second part 2312 to the first side 221A.

[0125] It should be noted that, in some embodiments, the shortest distance from the fourth portion 2314 to the third side 221C may not be equal to the shortest distance from the second portion 2312 to the first side 221A, so that the distances of the explosion-proof valve 23 from the first side 221A and the third side 221C are not equal. In some embodiments, the thickness of the fourth portion 2314 is less than the thickness of the second portion 2312, and the shortest distance from the fourth portion 2314 to the third side 221C is greater than the shortest distance from the second portion 2312 to the first side 221A, so as to reduce the impact of the periodic stress of the expansion of the electrode assembly 21 on the fourth portion 2314 by increasing the distance from the fourth portion 2314 to the third side 221C. Similarly, the thickness of the second part 2312 is less than the thickness of the fourth part 2314, and the shortest distance of the fourth part 2314 from the third side 221C is less than the shortest distance of the second part 2312 from the first side 221A, so as to reduce the influence of the periodic stress of the expansion of the electrode assembly 21 on the second part 2312 by increasing the distance of the second part 2312 from the first side 221A.

[0126] By making the shortest distance between the fourth part 2314 and the third side 221C equal to the shortest distance between the second part 2312 and the first side 221A, the explosion-proof valve 23 is made to be equidistant from the first side 221A and the third side 221C, thereby balancing the expansion stress on the explosion-proof valve 23.

[0127] According to some embodiments of this application, along the thickness direction of the first shell wall 221, the thickness of the fourth portion 2314 at the shortest distance from the third side 221C is equal to the thickness of the second portion 2312 at the shortest distance from the first side 221A.

[0128] Along the thickness direction of the first shell wall 221, the thickness of the fourth part 2314 at the shortest distance from the third side 221C is equal to the thickness of the second part 2312 at the shortest distance from the first side 221A. This means that the thickness of the point at the shortest distance of the fourth part 2314 from the third side 221C is equal to the thickness of the point at the shortest distance of the second part 2312 from the first side 221A.

[0129] In some embodiments, the thickness of the point at the shortest distance from the third side 221C in the fourth part 2314 may be equal to the thickness of the point at the shortest distance from the first side 221A in the second part 2312, while the thickness of the remaining points in the fourth part 2314 may be different from the thickness of the remaining points in the second part 2312. Alternatively, the thickness of multiple points in the fourth part 2314 may be the same as the thickness of multiple points in the second part 2312.

[0130] By making the thickness of the fourth part 2314 at the shortest distance from the third side 221C equal to the thickness of the second part 2312 at the shortest distance from the first side 221A along the thickness direction of the first shell wall 221, the stress on both sides of the explosion-proof valve 23 is evenly distributed.

[0131] Please continue reading. Figures 5-6 According to some embodiments of this application, the first shell wall 221 includes a mounting hole 221D; the explosion-proof valve 23 further includes a connecting portion 232 and a body portion 233. The connecting portion 232 is used to connect with the wall of the hole forming the mounting hole 221D. A weak portion 231 is located between the connecting portion 232 and the body portion 233, and the weak portion 231 is disposed around the body portion 233. Along the thickness direction of the first shell wall 221, the thickness of both the body portion 233 and the connecting portion 232 is greater than the thickness of the weak portion 231.

[0132] It should be noted that, Figure 6 A-A' is an exploded structural diagram of the first shell wall 221 and the explosion-proof valve 23.

[0133] Mounting hole 221D refers to a through hole that penetrates the first shell wall 221 along its thickness direction. The explosion-proof valve 23 is mounted in mounting hole 221D, and the connecting part 232 is connected to the wall of mounting hole 221D. A weak portion 231 connects the connecting part 232 and the main body 233, and the weak portion 231 is arranged around the main body 233. For example, the first part 2311, the second part 2312, the third part 2313, and the fourth part 2314 of the weak portion 231 are connected end-to-end and arranged around the main body 233.

[0134] In some embodiments, the orthographic projection of the weak portion 231 in a projection plane parallel to the first shell wall 221 is rectangular, racetrack-shaped, or similar. In some embodiments, to better distribute stress, the orthographic projection of the weak portion 231 in a projection plane parallel to the first shell wall 221 is racetrack-shaped.

[0135] In some embodiments, the first portion 2311 includes a first sub-part and a second sub-part connected to each other; the second portion 2312 includes a third sub-part and a fourth sub-part connected to each other; the third portion 2313 includes a fifth sub-part and a sixth sub-part connected to each other; and the fourth portion 2314 includes a seventh sub-part and an eighth sub-part connected to each other. The first sub-part and the eighth sub-part are connected to form a first curved portion; the second sub-part and the third sub-part are connected to form a first straight portion; the fourth sub-part and the fifth sub-part are connected to form a second curved portion; and the sixth sub-part and the seventh sub-part are connected to form a second straight portion. The second straight portion is parallel to and opposite to the first straight portion.

[0136] In some embodiments, the first sub-part and the eighth sub-part connect at the apex of the first curved portion to facilitate quick determination of the boundary point between the first portion 2311 and the fourth portion 2314. The fourth sub-part and the fifth sub-part connect at the apex of the second curved portion to facilitate quick determination of the boundary point between the second portion 2312 and the third portion 2313. Along the length direction of the first straight portion, the ratio of the length of the third sub-part to the length of the first straight portion is greater than or equal to 1 / 5 and less than or equal to 1 / 2, and the ratio of the length of the seventh sub-part to the length of the second straight portion is greater than or equal to 1 / 5 and less than or equal to 1 / 2, to facilitate the manufacture of the first portion 2311, the second portion 2312, the third portion 2313, and the fourth portion 2314. In some embodiments, the ratio of the length of the third sub-part to the length of the first straight portion is equal to 1 / 5, 1 / 4, 1 / 3, or 1 / 2, and the ratio of the length of the seventh sub-part to the length of the second straight portion is equal to 1 / 5, 1 / 4, 1 / 3, or 1 / 2.

[0137] It should be noted that the boundary positions between the various parts of the weak part 231 can be determined comprehensively based on factors such as the expansion stress of the electrode assembly 21, the size of the first shell wall 211, and the tilt angle of the explosion-proof valve 23 relative to the first side 211.

[0138] Because the internal pressure of the battery cell 20 fluctuates during transportation, temperature changes, or charging and discharging, the body 233 of the explosion-proof valve 23 may bulge away from the electrode assembly 21 or concave towards the electrode assembly 21. When this alternating bulging and concavity occurs, the weak portion 231 also bears alternating stress, leading to alternating fatigue aging or fracture. This results in a decrease in the strength of the connection to the weak portion 231, making it prone to rupture before the internal pressure of the battery cell 20 reaches the preset pressure value, thus releasing the internal pressure and causing the explosion-proof valve 23 to crack under non-design conditions. Therefore, making the thickness of both the body 233 and the connecting portion 232 greater than the thickness of the weak portion 231 strengthens their structural strength, reduces the degree of bulging or concavity deformation of the body 233, and consequently reduces the alternating stress borne by the weak portion 231, improving the safety and stability of the battery.

[0139] By including a connecting portion 232 and a body portion 233 in the explosion-proof valve 23, with the connecting portion 232 connected to the wall of the mounting hole 221D formed on the first shell wall 221, the weak portion 231 is located between the connecting portion 232 and the body portion 233, and the weak portion 231 is arranged around the body portion 233. Along the thickness direction of the first shell wall 221, the thickness of both the body portion 233 and the connecting portion 232 is greater than the thickness of the weak portion 231, which can strengthen the structural strength of the body portion 233 and the connecting portion 232, thereby reducing the degree of bulging or denting deformation of the body portion 233, which in turn helps to reduce the alternating stress borne by the weak portion 231, and improves the safety and stability of the battery.

[0140] Please continue reading. Figures 7-8 According to some embodiments of this application, the weak portion 231 is formed by providing a groove in the first shell wall 221.

[0141] The weak portion 231 is formed by providing a groove in the first shell wall 221, so that the thickness of the weak portion 231 is less than the thickness of the main body portion 233, thereby making the strength of the main body portion 233 greater than the strength of the weak portion 231.

[0142] In some embodiments, material can be removed from the first shell wall 221 by machining to form a groove, which helps to reduce processing costs and processing difficulty. In some examples, the area enclosed by the groove can be a racetrack shape, a circle, a rectangle, or an ellipse.

[0143] In some examples, a groove is provided on the side surface of the first shell wall 221 facing the electrode assembly 21 to form a weak part 231, so that the side surface of the first shell wall 221 facing the electrode assembly 21 has a thickness difference, so that when the pressure inside the battery cell 20 is greater than a threshold, the stress is concentrated at the thickness change of the first shell wall 221, thereby causing the weak part 231 to break.

[0144] It should be noted that in some embodiments, the explosion-proof valve 23 can be provided independently of the first shell wall 221. Accordingly, the weak portion 231 is formed by providing a groove on the explosion-proof valve 23. In some embodiments, the groove is annular. The connecting portion 232 and the body portion 233 are respectively located on both sides of the groove along its own width direction, and the weak portion 231 is provided around the body portion 233.

[0145] By forming a weak section 231 by providing a groove in the first shell wall 221, it is beneficial to reduce processing costs and processing difficulty.

[0146] Please continue reading. Figures 3-4 According to some embodiments of this application, the housing assembly 22 includes a housing 22A and an end cap 22B. The housing 22A includes a receiving cavity for accommodating the electrode assembly 21 and an opening communicating with the receiving cavity. The end cap 22B closes to the opening. A first housing wall 221 is a wall of the housing 22A.

[0147] End cap 22B refers to a component that covers the opening of housing 22A to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 22B can be adapted to the shape of housing 22A to fit the housing 22A. Optionally, end cap 22B can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 22B is less prone to deformation under pressure and impact, enabling battery cell 2020 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 222 can be provided on end cap 22B. Electrode terminals 222 can be used for electrical connection with electrode assembly 21 to output or input electrical energy to battery cell 20. The material of end cap 22B can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, an insulating member can also be provided on the inner side of end cap 22B. The insulating member can be used to isolate the electrical connection components inside housing 22A from end cap 22B to reduce the risk of short circuit. For example, the insulating element can be made of plastic, rubber, etc.

[0148] The housing 22A is a component used to cooperate with the end cap 22B to form the internal environment of the battery cell 20. The housing 22A and the end cap 22B can be independent components. An opening can be provided on the housing 22A, and the end cap 22B closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 22B and the housing 22A can be integrated. Specifically, the end cap 22B and the housing 22A can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22A, the end cap 22B closes the housing 22A. The housing 22A can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22A can be determined according to the specific shape and size of the electrode assembly 21. The housing 22A can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0149] In some embodiments, end cap 22B is a first shell wall 221. In other embodiments, one wall of shell 22A is the first shell wall 221.

[0150] In some embodiments, the thickness of the end cap 22B is greater than the thickness of the housing 22A, making the probability of the end cap 22B deforming under expansion stress lower than the probability of the housing 22A deforming under expansion stress. Therefore, when the end cap 22B serves as the first housing wall 221, the probability of the explosion-proof valve 23 cracking under non-design conditions is lower than when the housing 22A includes the first housing wall 221.

[0151] In some embodiments, housing 22A includes a bottom wall and a side wall. When end cap 22B is closed at the opening, the bottom wall and end cap 22B are positioned opposite each other, and the side wall connects the bottom wall and end cap 22B. One of the bottom wall and side wall serves as a first housing wall 221.

[0152] In some embodiments, the electrode terminals 222 of the positive and negative electrode tabs of the electrode assembly 21 are both disposed on the end cap 22B, and the bottom wall disposed opposite to the end cap 22B serves as the first shell wall 221, such as... Figure 3 As shown.

[0153] In some embodiments, the housing assembly 22 may include two end caps 22B disposed opposite to each other, with electrode terminals for connecting the positive and negative electrode tabs of the electrode assembly 21 respectively disposed on the two end caps 22B. The housing 22A includes a sidewall connecting the two end caps 22B. The sidewall serves as a first housing wall 221, such as... Figure 4 As shown.

[0154] It should be noted that when the shell 22A includes a bottom wall and a side wall, the side wall can still be selected as the first shell wall 221.

[0155] By including a housing 22A and an end cap 22B in the housing assembly 22, the housing 22A includes a receiving cavity for accommodating the electrode assembly 21 and an opening communicating with the receiving cavity. The end cap 22B closes to the opening. A first housing wall 221 is a wall of the housing 22A to reduce the probability of the explosion-proof valve 23 cracking under non-design conditions when the housing 22A includes the first housing wall 221.

[0156] Please continue reading. Figure 2 This application provides a battery device that includes the battery cell 20 described in the above embodiments.

[0157] The battery device may be simply referred to as a battery, and the battery can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery can be a secondary battery or a primary battery.

[0158] It is understood that the battery device provided in this application includes any of the aforementioned battery cells 20, and therefore, the battery device has all the beneficial effects of the aforementioned battery cells, which will not be elaborated here.

[0159] This application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0160] Electrical devices can include mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, and so on.

[0161] It is understood that the electrical device provided in this application, by using any of the aforementioned battery devices, has all the beneficial effects of the aforementioned battery devices, which will not be elaborated here.

[0162] This application provides an energy storage device, which includes the battery device described in the above embodiments, the battery device being used to store electrical energy.

[0163] Energy storage devices can include, but are not limited to, centralized energy storage devices (such as containerized energy storage devices), distributed energy storage devices, mobile energy storage devices, wearable energy storage devices, and so on.

[0164] It is understood that the energy storage device provided in this application, by using any of the aforementioned batteries, possesses all the beneficial effects of the aforementioned batteries, which will not be elaborated further here.

[0165] The battery cell of this application is described below with reference to a specific embodiment.

[0166] This application provides a battery cell 20, including an electrode assembly 21, a housing assembly 22, and an explosion-proof valve 23.

[0167] The housing assembly 22 is used to accommodate the electrode assembly 21. The housing assembly 22 includes a housing 22A and an end cap 22B. The housing 22A includes multiple walls that are connected to form a receiving cavity for accommodating the electrode assembly 21. The housing 22A also includes an opening communicating with the receiving cavity. The end cap 22B closes to the opening. One of the multiple walls serves as a first housing wall 221, which is rectangular. The first housing wall 221 has a first side 221A, a second side 221B, and a third side 221C. The first side 221A and the third side 221C both intersect with the second side 221B. The third side 221C is parallel to and opposite to the first side 221A. The size of the first side 221A is larger than the size of the second side 221B. The first housing wall 221 has a first region 2211 and a second region 2212 that are evenly divided and connected along the extending direction of the second side 221B.

[0168] An explosion-proof valve 23 is disposed on the first shell wall 221. The length direction of the explosion-proof valve 23 intersects the extension directions of the first side 221A and the second side 221B. Furthermore, the acute angle formed between the first side 221A and the extension line extending along the length direction of the explosion-proof valve 23 is greater than 0° and less than or equal to 45°.

[0169] The explosion-proof valve 23 includes a weak portion 231. The portion of the weak portion 231 located in the first zone 2211 includes a connected first part 2311 and a second part 2312. The portion of the weak portion 231 located in the second zone 2212 includes a connected third part 2313 and a fourth part 2314. Along the thickness direction of the first shell wall 221, the thickness of the first part 2311 is less than or equal to the thickness of the second part 2312, and the thickness of the third part 2313 is less than or equal to the thickness of the fourth part 2314. Along the extension direction of the second side 221B, the shortest distance of the second part 2312 from the first side 221A is less than the shortest distance of the first part 2311 from the first side 221A, and the shortest distance of the fourth part 2314 from the third side 221C is less than the shortest distance of the third part 2313 from the third side 221C. In Part 2312, the ratio of the distance from any point to the first side 221A to the distance to the second side 221B is greater than 0 and less than or equal to 0.2. In Part 4314, the ratio of the distance from any point to the third side 221C to the distance to the second side 221B is greater than 0 and less than or equal to 0.2.

[0170] The battery cell 20 provided in this application can disperse the periodic stress applied to the explosion-proof valve 23 due to the expansion of the electrode assembly 21, and avoid stress concentration in a single direction, thereby improving the cracking problem of the explosion-proof valve 23 under non-design conditions.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: Electrode assembly; A housing assembly for accommodating the electrode assembly, the housing assembly including a rectangular first housing wall having intersecting first and second sides; as well as An explosion-proof valve is disposed on the first shell wall, and the length direction of the explosion-proof valve intersects the extension direction of the first side and the second side.

2. The battery cell according to claim 1, characterized in that, The size of the first side is larger than the size of the second side, and the acute angle formed between the first side and the extension line extending along the length direction of the explosion-proof valve is the first included angle; Wherein, the first included angle is greater than 0° and less than or equal to 45°.

3. The battery cell according to claim 1 or 2, characterized in that, The explosion-proof valve includes a weak portion, and the first shell wall has a first region and a second region that are evenly divided and connected along the extension direction of the second side, with the first side located in the first region; the portion of the weak portion located in the first region includes a connected first part and a second part. Wherein, along the thickness direction of the first shell wall, the thickness of the first part is less than or equal to the thickness of the second part; along the extension direction of the second side, the shortest distance of the second part from the first side is less than the shortest distance of the first part from the first side.

4. The battery cell according to claim 3, characterized in that, Along the extension direction of the second side, the shortest distance between the second part and the first side is greater than or equal to 3 mm.

5. The battery cell according to claim 3, characterized in that, Along the extension direction of the second side, the ratio of the distance from any point in the second part to the distance from the first side to the distance from the second side is greater than 0 and less than or equal to 0.

2.

6. The battery cell according to claim 3, characterized in that, Along the extension direction of the second side, the distance from any point in the second part to the first side is less than or equal to the distance from any point in the first part to the first side.

7. The battery cell according to claim 3, characterized in that, The thickness of the second part along the thickness direction of the first shell wall gradually decreases as the distance from the first edge increases.

8. The battery cell according to claim 3, characterized in that, The weak portion located in the second region includes a connected third and fourth portion; The third part and the first part are arranged in a centrally symmetrical manner about the centroid of the first shell wall, and the fourth part and the second part are arranged in a centrally symmetrical manner about the centroid of the first shell wall.

9. The battery cell according to claim 3, characterized in that, The first shell wall also includes a third side that is parallel to and opposite to the first side; The weak portion located in the second region includes a connected third and fourth portion; Wherein, along the thickness direction of the first shell wall, the thickness of the third part is less than or equal to the thickness of the fourth part; along the extension direction of the second side, the shortest distance of the fourth part from the third side is less than the shortest distance of the third part from the third side.

10. The battery cell according to claim 9, characterized in that, The shortest distance from the fourth part to the third side is equal to the shortest distance from the second part to the first side.

11. The battery cell according to claim 9, characterized in that, Along the thickness direction of the first shell wall, the thickness of the fourth part at the shortest distance from the third side is equal to the thickness of the second part at the shortest distance from the first side.

12. The battery cell according to claim 3, characterized in that, The first shell wall includes mounting holes; The explosion-proof valve further includes a connecting part and a body part. The connecting part is used to connect with the wall of the hole forming the mounting hole. The weak part is located between the connecting part and the body part, and the weak part is arranged around the body part. Wherein, along the thickness direction of the first shell wall, the thickness of the main body and the connecting part are both greater than the thickness of the weak part.

13. The battery cell according to claim 3, characterized in that, The weak part is formed by creating a groove in the first shell wall.

14. The battery cell according to any one of claims 1 to 13, characterized in that, The housing assembly includes: A housing, the housing including a receiving cavity for receiving the electrode assembly and an opening communicating with the receiving cavity; and End cap, which closes the opening; Wherein, the first shell wall is one wall of the shell.

15. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 14.

16. An electrical appliance, characterized in that, Includes the battery device as described in claim 15, wherein the battery device is used to provide electrical energy.

17. An energy storage device, characterized in that, Includes the battery device as described in claim 15, wherein the battery device is used to store electrical energy.

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