Battery monomer, battery device, energy storage device and power utilization device

Abstract

The utility model is applicable to the technical field of batteries, and provides a battery monomer, a battery device, an energy storage device and a power utilization device, the battery monomer comprises a shell, and an accommodating space is arranged in the shell; the electrode assembly is arranged in the accommodating space; the pressure relief mechanism is arranged on the shell, and the pressure relief mechanism is used for releasing the internal pressure of the battery monomers; the shell comprises a first wall, the first wall is provided with a concave part and a body part which are distributed in the first direction, the concave part is sunken towards the containing space relative to the body part, the shell is provided with a first shell part and a second shell part which are distributed in the first direction, the concave part is arranged on the first shell part, and the body part is arranged on the second shell part. The pressure relief mechanism is at least partially arranged on the second shell part. The battery cell provided by the embodiment of the utility model can reliably release pressure, and the reliability of the battery device is improved.

Description

Technical Field

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

[0002] 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.

[0003] The reliability of battery devices is a crucial issue. Therefore, improving the reliability of battery devices is a pressing technical problem that needs to be solved in battery technology. Utility Model Content

[0004] In view of this, embodiments of this application provide a battery cell, a battery device, an energy storage device, and an electrical device, thereby improving the reliability of the battery device.

[0005] An embodiment of the first aspect of this application provides a battery cell, comprising: a housing having an accommodating space therein; an electrode assembly disposed within the accommodating space; and a pressure relief mechanism disposed on the housing for releasing internal pressure of the battery cell; the housing includes a first wall having a recess and a body portion, the recess being recessed toward the accommodating space relative to the body portion; the housing has a first housing portion and a second housing portion distributed along a first direction, the recess being disposed in the first housing portion, the body portion being disposed in the second housing portion, and the pressure relief mechanism being at least partially disposed in the second housing portion.

[0006] In the battery cell provided in this application embodiment, a recess and a body portion distributed along a first direction are provided on the first wall of the outer casing, and the outer casing has a first shell portion and a second shell portion distributed along the first direction. At least part of the pressure relief mechanism is provided in the second shell portion. Thus, during the process of gas flowing to the pressure relief mechanism, the gas flows from the smaller pressure relief space formed by the first shell portion to the larger pressure relief space formed by the second shell portion, which can shorten the time for the gas to reach the pressure relief mechanism. Therefore, when the internal pressure or temperature of the battery cell reaches a threshold, the gas inside the battery cell can flow rapidly towards the pressure relief mechanism, shortening the time for the gas to reach the pressure relief mechanism, reducing the gas pressure at the gas generation location, improving the timeliness of pressure relief, thereby reducing the risk of the battery cell exploding due to untimely pressure relief or excessive pressure, and improving the reliability of the battery cell.

[0007] In some embodiments, in the housing, a first cross-section is defined as a cross-section perpendicular to the first wall and the first direction and passing through the recess, and a second cross-section is defined as a cross-section perpendicular to the first wall and the first direction and passing through the body portion, wherein the area of ​​the first cross-section is smaller than the area of ​​the second cross-section.

[0008] By adopting the above technical solution, the recess and the body can be arranged in any direction of the outer shell, and the gas generated by the electrode assembly can flow from the position with a smaller cross-section to the pressure relief mechanism, which reduces the time and pressure of the gas reaching the pressure relief mechanism and improves the reliability of the battery cell.

[0009] In some embodiments, the height of the body portion extending beyond the recess is H, wherein 2mm≤H≤10mm.

[0010] By adopting the above technical solutions, the pressure relief speed can be effectively improved and the pressure relief pressure can be reduced, while the impact on space utilization can be minimized.

[0011] In some embodiments, the housing includes a top wall and a bottom wall disposed opposite to each other, and two first side walls and two second side walls disposed between the top wall and the bottom wall, wherein the second side walls are the walls with the largest area in the housing; the top wall and the bottom wall are disposed opposite to each other along the height direction of the housing, the two first side walls are disposed opposite to each other along the length direction of the housing, and the two second side walls are disposed opposite to each other along the width direction of the housing; the first wall is the top wall, the bottom wall, the first side wall, or the second side wall.

[0012] By adopting the above technical solution, the position of the recess can be flexibly set so that the outer shell forms a small pressure relief space in the recess, which facilitates the smooth and rapid flow of gas to the pressure relief mechanism.

[0013] In some embodiments, the first wall is a top wall, and the recesses and the body portion are distributed along the length direction of the outer shell; the pressure relief mechanism is provided on the first side wall.

[0014] By adopting the above technical solution, the pressure relief space at the pressure relief mechanism is larger than the pressure relief space at the recess along the length of the outer casing, so that the gas can flow quickly to the pressure relief mechanism for pressure relief, thereby improving the reliability of the battery cell.

[0015] In some embodiments, the recess is located in the middle of the top wall along its length, and the battery cell also includes two electrode terminals with opposite polarities, which are disposed in the recess.

[0016] By adopting the above technical solution, the two electrode terminals are located in the recess, which reduces the space occupied by the electrode terminals and improves the space utilization of the battery device.

[0017] In some embodiments, the electrode terminals do not extend beyond the body portion in the direction from the bottom wall to the top wall.

[0018] By adopting the above technical solution, the electrode terminals can be hidden in the recessed area of ​​the outer shell, further reducing the space occupied by the electrode terminals.

[0019] In some embodiments, the electrode assembly includes two tabs of opposite polarity, at least a portion of which is disposed opposite to the body portion on the end cap, and the two tabs are connected to two electrode terminals in a one-to-one correspondence.

[0020] By adopting the above technical solution, at least a portion of the two tabs of the electrode assembly are arranged opposite to the body portion on the top wall, reducing the space of the tabs and electrode terminals in the height direction of the battery cell and further improving the space utilization of the battery device.

[0021] In some embodiments, the battery device further includes an insulating member connected to the top wall. The insulating member includes an insulating body and a boss. The insulating body is connected to the side of the top wall facing the receiving space, and the boss is connected to the end of the insulating body near the pressure relief mechanism and extends toward the receiving space. The boss has a through hole for accessing the pressure relief mechanism.

[0022] By adopting the above technical solution, the risk of short circuits in individual battery cells is reduced; the through holes on the boss allow gas to flow through, enabling the gas to flow smoothly to the pressure relief mechanism for pressure relief.

[0023] In some embodiments, the first wall is a first side wall, and the pressure relief mechanism is disposed on the top wall; the recess and the body portion are distributed on the first side wall along the height direction of the housing, and the recess is disposed on the side of the body portion away from the end cap.

[0024] By adopting the above technical solution, the pressure relief space at the pressure relief mechanism is larger than the pressure relief space at the recess along the height direction of the outer shell; by setting the recess on the first side wall of the shell, the pressure relief stability is improved without affecting the mutual support between the battery cells and adjacent battery cells.

[0025] In some embodiments, the first sidewall has an outwardly extending first protrusion located at one end of the first sidewall near the top wall, and the remaining portion of the first sidewall is formed as a recess; the top wall has a second protrusion connected to the first protrusion.

[0026] By making the end of the first sidewall near the top wall into the main body, the outer shell is relatively simple to manufacture and has a low cost.

[0027] In some embodiments, both first sidewalls are provided with recesses and body portions.

[0028] By adopting the above technical solution, the pressure relief speed has been further improved.

[0029] In some embodiments, the recesses on the two first sidewalls are positioned opposite each other.

[0030] By adopting the above technical solution, the pressure relief spaces on both sides of the outer casing along its length are symmetrically arranged, which is conducive to the uniform flow of gas on both sides of the outer casing.

[0031] In some embodiments, the size of the body portion is smaller than the size of the recess portion along the height direction of the housing.

[0032] By adopting the above technical solutions, the space utilization rate of battery devices can be improved.

[0033] In some embodiments, electrode terminals are disposed on the top wall, the first wall is the bottom wall, and the recess and the body portion are distributed on the bottom wall along the width direction of the housing; the pressure relief mechanism is disposed on the bottom wall and located on the body portion, and the area of ​​the cross-section of the housing through the pressure relief mechanism along its height and length directions is greater than the area of ​​the second side wall.

[0034] By adopting the above technical solution, the pressure relief space at the pressure relief mechanism is larger than the pressure relief space at the recess along the width direction of the outer shell. This facilitates the rapid flow of gas from the pressure relief space corresponding to the recess to the pressure relief mechanism, thereby improving the reliability of pressure relief and the reliability of the battery cell.

[0035] In some embodiments, a recess surrounds the body portion on the bottom wall.

[0036] By adopting the above technical solutions, the reliability of pressure relief and the reliability of individual battery cells have been further improved.

[0037] In some embodiments, the bottom wall, two first side walls and two second side walls are integrally formed to form a shell, and an opening is formed at one end of the shell away from the bottom wall, and the top wall covers the opening.

[0038] By adopting the above technical solutions, the processing efficiency of the outer shell can be improved.

[0039] An embodiment of the second aspect of this application provides a battery device comprising a battery cell as provided in the first aspect.

[0040] An embodiment of the third aspect of this application provides an energy storage device, including a battery cell as described in the first aspect or a battery device as described in the second aspect, wherein the battery cell or battery device is used to store or provide electrical energy.

[0041] An embodiment of the fourth aspect of this application provides an electrical device, such as a battery cell of the first aspect, a battery device of the second aspect, or an energy storage device of the third aspect.

[0042] 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

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or conventional technology 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 these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0045] Figure 2 This is an exploded view of a battery device provided in an embodiment of this application;

[0046] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application;

[0047] Figure 4 This is a three-dimensional schematic diagram of a battery cell provided in an embodiment of this application;

[0048] Figure 5 yes Figure 4 The front view of the battery cell shown;

[0049] Figure 6 yes Figure 4 A three-dimensional schematic diagram of the top wall and insulating components in a single battery cell;

[0050] Figure 7 This is a three-dimensional schematic diagram of a battery cell provided in another embodiment of this application;

[0051] Figure 8 This is a three-dimensional schematic diagram of a battery cell provided in another embodiment of this application.

[0052] The markings in the diagram mean:

[0053] 1000, Vehicle; 100, Battery assembly; 10, Housing; 11, Upper housing; 12, Lower housing; 20, Battery cell assembly; 21, Battery cell; 211, Housing; 2011, First wall; 2011a, Recess; 2011b, Body part; 211a, First housing part; 211b, Second housing part; 2111, Top wall; 2112, Bottom wall; 2113, First side wall; 2114, Second side wall; 212, Electrode assembly; 2121, Tab; 213, Pressure relief mechanism; 214, Electrode terminal; 215, Insulating component; 2151, Insulating body; 2152, Boss; 21521, Through hole. Detailed Implementation

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0059] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0060] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the 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.

[0061] 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.

[0062] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0063] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0064] The reliability of battery devices is a crucial issue. A battery device typically consists of a casing and multiple individual battery cells housed within it. Within each battery cell, repeated charge-discharge cycles lead to side reactions and the continuous generation of gas, creating internal pressure. As this pressure increases, gas between the electrodes cannot be expelled in time, affecting lithium-ion insertion and extraction, potentially leading to lithium plating. Furthermore, if a short circuit or thermal runaway occurs within a battery cell, the internal pressure will continue to rise. To ensure battery cell safety, pressure relief mechanisms are typically installed on the battery cell casing to release the generated gas and relieve pressure, thus guaranteeing the battery cell's safety.

[0065] If the location where gas is generated in a battery cell is far from the pressure relief mechanism, the time it takes for the gas to travel to the pressure relief mechanism and then to the outside of the battery cell is relatively long. If the pressure relief is not timely and the pressure relief is high, it may cause the battery cell to explode.

[0066] In view of this, embodiments of this application provide a battery cell, including a housing, an electrode assembly, and a pressure relief mechanism. The housing has a receiving space; the electrode assembly is disposed in the receiving space; the pressure relief mechanism is disposed on the housing and is used to release the internal pressure of the battery cell; the housing includes a first wall, the first wall has a recess and a body portion distributed along a first direction, the recess is recessed relative to the body portion toward the receiving space, the housing has a first shell portion and a second shell portion distributed along the first direction, the recess is disposed in the first shell portion and the body portion is disposed in the second shell portion, and the pressure relief mechanism is at least partially disposed in the second shell portion.

[0067] In the battery cell provided in this application embodiment, the first wall of the outer shell has a recess and a body portion. The pressure relief space corresponding to the first shell portion is smaller than the pressure relief space corresponding to the second shell portion. In this way, the gas generated after thermal runaway of the electrode assembly is transmitted from the area with smaller pressure relief space to the area with larger pressure relief space and the pressure relief mechanism. Under the same pressure relief flow rate, the pressure relief space at the pressure relief mechanism is larger, so the pressure relief time and pressure relief can be reduced. This is beneficial for releasing the internal pressure of the battery cell, reducing the risk of the battery cell exploding due to untimely pressure relief or excessive pressure, and improving the reliability of the battery cell and battery device.

[0068] The technical solutions described in the embodiments of this application are applicable to battery devices, energy storage devices, and electrical devices that use battery devices.

[0069] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0070] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0071] The battery device disclosed in this application can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. Examples of electrical devices include mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0072] The energy storage device provided in this application includes one or more battery clusters to improve the voltage and capacity of the energy storage device. A battery cluster may include multiple battery devices, which are connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0073] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0074] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0075] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0076] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0077] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0078] 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.

[0079] refer to Figure 2 , Figure 2 This is an exploded structural diagram of a battery device 100 provided in some embodiments of this application. The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies 20 for providing voltage and capacity. A battery cell assembly 20 may include multiple battery cells 21, which are connected in series, parallel, or mixed connections via busbars.

[0080] In some embodiments, the multiple battery cells 21 in the battery device 100 can be electrically connected through a busbar to achieve parallel, series, or mixed connection of the multiple battery cells 21 in the battery device 100.

[0081] In some embodiments, the battery cell assembly 20 is typically formed by arranging multiple battery cells 21; as an example, the battery cell assembly 20 can be a battery module, which is formed by arranging and fixing multiple battery cells 21 into an independent module. As an example, the battery module can be formed by bundling multiple battery cells 21 together with cable ties.

[0082] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 10 and one or more battery cell assemblies 20, the battery cell assemblies 20 being housed within the housing 10.

[0083] As an example, the battery cell assembly 20 can be a battery module, and the battery cell assembly 21 can be housed in the housing 10 by fixing the battery module in the housing 10.

[0084] As an example, the battery cell assembly 20 can also be housed in the housing 10 by directly fixing multiple battery cells 21 to the housing 10.

[0085] As an example, the housing 10 may include an upper housing 11 and a lower housing 12. The upper housing 11 and the lower housing 12 are fastened together, forming a closed receiving cavity inside the housing 10 to house the battery cell assembly 20. Here, "closed" refers to covering or closing, and can be either sealed or unsealed.

[0086] As an example, the housing 10 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 10 forms a closed receiving cavity to house the battery cell assembly 20.

[0087] As an example, the housing 10 can be part of the chassis structure of the vehicle 1000. For example, the top cover of the housing 10 can be at least part of the floor of the vehicle 1000, or the frame of the housing 10 can be at least part of the crossbeams and longitudinal beams of the vehicle 1000.

[0088] In some embodiments, battery device 100 refers to an energy storage device, which includes a housing 10, and at least one side of the housing 10 has a door. The energy storage device includes energy storage containers, energy storage cabinets, etc.

[0089] Please refer to Figure 3 The battery cell 21 is the smallest unit that makes up the battery device. The battery cell 21 includes a housing 211, an electrode assembly 212, and other functional components. The housing 211 is provided with functional components such as electrode terminals 214 and a pressure relief mechanism 213. The electrode terminals 214 are connected to the tabs of the electrode assembly 212 to realize the input and output of electrical energy, and the pressure relief mechanism 213 is used to release the internal pressure of the battery cell 21.

[0090] Figure 4 This is a perspective view of a battery cell 21 provided in an embodiment of this application. Figure 5 yes Figure 4 The front view of the battery cell 21 shown. Figure 4The X direction in the diagram indicates the width of the battery cell 21, the Y direction indicates the length of the battery cell 21, and the Z direction indicates the height of the battery cell 21.

[0091] Please refer to Figure 4 , Figure 5 An embodiment of the first aspect of this application provides a battery cell 21, including a housing 211, an electrode assembly 212, and a pressure relief mechanism 213. The housing 211 has a receiving space, and the electrode assembly 212 is disposed within the receiving space. The pressure relief mechanism 213 is disposed on the housing 211 and is used to release the internal pressure of the battery cell 21. The housing 211 includes a first wall 2011, which has a recess 2011a and a body portion 2011b distributed along a first direction. The recess 2011a is recessed relative to the body portion 2011b in the direction toward the receiving space. The housing 211 has a first shell portion 211a and a second shell portion 211b distributed along the first direction. The recess 2011a is disposed in the first shell portion 211a, the body portion 2011b is disposed in the second shell portion 211b, and the pressure relief mechanism 213 is at least partially disposed in the second shell portion 211b.

[0092] The outer casing 211 is used to enclose a receiving space, which can be used to house the electrode assembly 212, the electrolyte, and other components. The outer casing 211 can be of various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the outer casing 211 can be determined according to the specific shape and size of the electrode assembly 212. The outer casing 211 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, or plastic.

[0093] Electrode assembly 212 is the component in the battery cell 21 where the electrochemical reaction occurs. The casing 211 may contain one or more electrode assemblies 212. The electrode assembly 212 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 body of the electrode assembly 212, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the body or separately at both ends of the body. During the charging and discharging process of the battery device, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals 214 to form a current loop.

[0094] The pressure relief mechanism 213 is a component or part that is actuated to release internal pressure when the internal pressure or temperature of the battery cell 21 reaches a predetermined threshold. This threshold design varies depending on design requirements. It may depend on one or more materials among the positive electrode, negative electrode, electrolyte, and separator in the battery cell 21. The internal pressure of the battery cell 21 is the same as the pressure inside the casing. The pressure relief mechanism 213 can take the form of an explosion-proof valve, a gas valve, a pressure relief valve, or a safety valve, and can specifically employ a pressure-sensitive element or structure. That is, when the internal pressure of the battery cell 21 reaches the predetermined threshold, the pressure relief mechanism 213 actuates or a weak point in the pressure relief mechanism 213 ruptures, thereby forming an opening or channel for releasing internal pressure. The pressure relief mechanism 213 and the casing 211 can be an integral structure, or they can be separately processed and then connected as one unit. For example, in embodiments where they are separate, they can be connected by welding, bonding, or snap-fitting.

[0095] The term "actuation" as used in this application refers to the pressure relief mechanism 213 being activated or undergoing a certain state, thereby releasing the internal pressure of the battery cell 21. The action of the pressure relief mechanism 213 may include, but is not limited to, at least a portion of the pressure relief mechanism 213 rupturing, breaking, tearing, or opening. When the pressure relief mechanism 213 is actuated, the high-temperature, high-pressure substances inside the battery cell 21 are discharged outwards from the actuated portion as waste. This method allows for pressure relief of the battery cell 21 under controllable pressure, thereby preventing potentially more serious accidents. The waste from the battery cell 21 mentioned in this application includes, but is not limited to, electrolyte, dissolved or broken positive and negative electrode plates, fragments of the separator, high-temperature, high-pressure gases generated during the reaction, flames, etc.

[0096] The pressure relief mechanism 213 is located on one side of the housing 211. The housing 211 includes a first wall 2011, and the first wall 2011 has a recess 2011a and a body portion 2011b distributed along a first direction. The first direction can be the height direction, length direction, or width direction of the housing 211. The first wall 2011 is a wall of the housing 211, and the first wall 2011 can be the top wall, bottom wall, or side wall of the housing 211. In this embodiment, the side wall that is provided with both the recess 2011a and the body portion 2011b is defined as the first wall 2011.

[0097] The recess 2011a is recessed relative to the body portion 2011b in the direction of the receiving space, that is, the recess 2011a is recessed towards the interior of the battery cell 21. The recess 2011a can be formed by recessing the outer surface of the first wall 2011 towards the interior of the battery cell 21. For example, the recess 2011a can be formed as a groove; for example, a portion of the first wall 2011 can be subjected to rolling, stamping or other methods to form a recess, and the remaining portion of the first wall 2011 is the body portion.

[0098] The number of recesses 2011a can be one or more, for example, such as Figure 4 and Figure 5 As shown, the first wall 2011 has a recess 2011a, and the rest of the first wall 2011 is the body portion 2011b.

[0099] The outer casing 211 has a first casing portion 211a and a second casing portion 211b distributed along a first direction, that is, along the first direction, the first casing portion 211a is correspondingly provided with the recess 2011a, and the second casing portion 211b is correspondingly provided with the body portion 2011b.

[0100] The pressure relief mechanism 213 is at least partially disposed in the second housing portion 211b, that is, the pressure relief mechanism 213 may be entirely located in the second housing portion 211b, or a portion of the pressure relief mechanism 213 may be disposed in the second housing portion 211b and another portion of the pressure relief mechanism 213 may be disposed in the first housing portion 211a. It can be understood that the pressure relief mechanism 213 may be disposed in the body portion 2011b of the first wall 2011, or in other portions of the second housing portion 211b.

[0101] Because the recess 2011a is recessed relative to the body portion 2011b toward the receiving space, the space formed by the first housing portion 211a is smaller than the space formed by the second housing portion 211b. Therefore, the pressure relief space formed by the battery cell 21 in the first housing portion 211a is smaller than the pressure relief space at at least part of the pressure relief mechanism 213. Figure 4 For example, the recess 2011a is provided in the middle of the first wall 2011 along its length direction, and the recess 2011a is recessed along the height direction of the battery cell 21. Thus, along the length direction of the battery cell 21, the pressure relief space of the first housing portion 211a is smaller than the pressure relief space at at least part of the pressure relief mechanism 213.

[0102] In the battery cell 21 provided in this application embodiment, the first wall 2011 of the outer casing 211 has a recess 2011a and a body portion 2011b. The pressure relief space corresponding to the recess 2011a is smaller than the pressure relief space corresponding to the body portion 2011b, forming a flared pressure relief space inside the outer casing 211. Since the pressure relief mechanism 213 is at least partially provided in the second casing portion 211b, the gas generated after the thermal runaway of the electrode assembly 212 flows from the pressure relief space corresponding to the recess 2011a through the pressure relief space corresponding to the body portion 2011b, and then flows to the pressure relief mechanism 213. That is, the gas is transferred from the area with a smaller pressure relief space to the area with a larger pressure relief space. Under the same pressure relief flow rate, the pressure relief space at the pressure relief mechanism 213 is larger, and the gas inside the battery cell 21 is more likely to flow to the pressure relief mechanism 213. Therefore, the pressure relief time and pressure relief can be reduced, improving the reliability of the battery cell 21.

[0103] In the battery cell 21 provided in this embodiment, the first wall 2011 of the outer casing 211 is provided with a recess 2011a and a body portion 2011b distributed along a first direction. The outer casing 211 has a first housing portion 211a and a second housing portion 211b distributed along the first direction. At least a portion of the pressure relief mechanism 213 is located in the second housing portion 211b. Thus, during the gas flow to the pressure relief mechanism 213, the gas flows from the smaller pressure relief space formed by the first housing portion 211a to the larger pressure relief space formed by the second housing portion 211b, shortening the time it takes for the gas to reach the pressure relief mechanism 213. Therefore, when the internal pressure or temperature of the battery cell 21 reaches a threshold, the gas inside the battery cell 21 can flow rapidly towards the pressure relief mechanism 213, shortening the time it takes for the gas to reach the pressure relief mechanism 213, reducing the gas pressure at the gas generation location, and improving the timeliness of pressure relief. This reduces the risk of the battery cell 21 exploding due to untimely pressure relief or excessive pressure, thereby improving the reliability of the battery cell 21.

[0104] Please refer to Figures 4 to 8 In some embodiments, in the housing 211, a cross section perpendicular to the first wall 2011 and the first direction and passing through the recess 2011a is designated as a first cross section, and a cross section perpendicular to the first wall 2011 and the first direction and passing through the body portion 2011b is designated as a second cross section, wherein the area of ​​the first cross section is smaller than the area of ​​the second cross section.

[0105] The first direction can be the length direction, width direction or height direction of the outer shell 211.

[0106] like Figure 4 , Figure 5 As shown, the first direction is the length direction (Y direction) of the outer shell 211. Figure 5The first housing portion 211a and the second housing portion 211b are indicated by dashed lines. The first wall 2011 is the side wall of the outer shell 211 along its height direction (Z direction). The recess 2011a and the body portion 2011b are distributed on the first wall 2011 along the length direction (Y direction) of the outer shell 211. Let the cross section perpendicular to the length direction of the first wall 2011 and the outer shell 211 and passing through the recess 2011a be the first cross section, and let the cross section perpendicular to the length direction of the first wall 2011 and the outer shell 211 and passing through the body portion 2011b be the second cross section. Both the first cross section and the second cross section are cross sections of the outer shell 211 along the ZX direction, and the area of ​​the first cross section is smaller than the area of ​​the second cross section.

[0107] like Figure 7 As shown, the first direction is the height direction (Z direction) of the outer shell 211, the first wall 2011 is the side wall of the outer shell 211 along its length direction (Y direction), and the recess 2011a and the body part 2011b are distributed on the first wall 2011 along the height direction (Z direction) of the outer shell 211. Figure 7 The first housing portion 211a and the second housing portion 211b are indicated by dashed lines. Let the cross section perpendicular to the height direction of the first wall 2011 and the outer shell 211 and passing through the recess 2011a be the first cross section, and let the cross section perpendicular to the height direction of the first wall 2011 and the outer shell 211 and passing through the body portion 2011b be the second cross section. Both the first cross section and the second cross section are cross sections of the outer shell 211 along the XY direction, and the area of ​​the first cross section is smaller than the area of ​​the second cross section.

[0108] like Figure 8 As shown, the first direction is the width direction (X direction) of the outer shell 211, the first wall 2011 is the sidewall of the outer shell 211 along its height direction (Z direction), and the recess 2011a and the body portion 2011b are distributed on the first wall 2011 along the width direction (X direction) of the outer shell 211. Let the cross-section perpendicular to the width direction of the first wall 2011 and the outer shell 211 and passing through the recess 2011a be the first cross-section, and let the cross-section perpendicular to the width direction of the first wall 2011 and the outer shell 211 and passing through the body portion 2011b be the second cross-section. Both the first and second cross-sections are cross-sections of the outer shell 211 along the ZY direction, and the area of ​​the first cross-section is smaller than the area of ​​the second cross-section. Optionally, the recess 2011a and the body portion 2011b are also simultaneously distributed on the first wall 2011 along the length direction (Y direction) of the outer shell 211.

[0109] By adopting the above technical solution, the recess 2011a and the body portion 2011b can be arranged in any direction along the outer shell 211, so that the cross-sectional area of ​​the outer shell 211 at the recess 2011a is smaller than the cross-sectional area at the body portion 2011b. At the same time, since the pressure relief mechanism 213 is at least partially provided in the second housing portion 211b, the gas generated by the electrode assembly 212 can flow from the position with the smaller cross-section to the pressure relief mechanism 213, reducing the time and pressure relief pressure for the gas to reach the pressure relief mechanism 213, and improving the reliability of the battery cell 21.

[0110] Please refer to Figures 4 to 8 In some embodiments, the height of the body portion 2011b extending beyond the recess 2011a is H, wherein 2mm≤H≤10mm.

[0111] The height H of the recess 2011a extending beyond the main body 2011b can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0112] In some embodiments, with Figures 4 to 6 Taking the illustrated embodiment as an example, the first wall 2011 has a recess 2011a and a body portion 2011b. The first wall 2011 and the bottom surface of the battery cell 21 are disposed opposite each other along the height direction of the battery cell 21. The height of the body portion 2011b refers to the distance H1 from the outer surface of the body portion 2011b to the bottom surface of the battery cell 21. The height of the recess 2011a refers to the distance H2 from the outer surface of the recess 2011a to the bottom surface of the outer casing 211. The height H of the body portion 2011b exceeding the recess 2011a is equal to the difference between H1 and H2. Please refer to... Figure 7 and Figure 8 In other embodiments, the recess 2011a may also be provided on the side wall or bottom wall of the battery cell 21, and the height difference between the recess 2011a and the body portion 2011b may also satisfy the above-mentioned range.

[0113] By setting the height of the main body 2011b beyond the recess 2011a to be greater than or equal to 2mm, and the pressure relief spaces corresponding to the main body 2011b and the recess 2011a to be different in size, the pressure relief speed can be effectively improved and the pressure relief pressure reduced; by setting the height of the main body 2011b beyond the recess 2011a to be less than or equal to 10mm, the impact on space utilization can be reduced.

[0114] In some embodiments, the outer casing 211 includes a top wall 2111 and a bottom wall 2112 disposed opposite to each other, and two first side walls 2113 and two second side walls 2114 disposed between the top wall 2111 and the bottom wall 2112, wherein the second side walls 2114 are the walls with the largest area in the outer casing 211; the top wall 2111 and the bottom wall 2112 are disposed opposite to each other along the height direction of the outer casing 211, the two first side walls 2113 are disposed opposite to each other along the length direction of the outer casing 211, and the two second side walls 2114 are disposed opposite to each other along the width direction of the outer casing 211; the first wall is the top wall 2111, the bottom wall 2112, the first side wall 2113 or the second side wall 2114.

[0115] The outer casing 211 is a component that isolates the internal environment of the battery cell 21 from the external environment. The internal environment formed by the outer casing 211 can be used to accommodate electrode components, electrolyte, and other components. The outer casing 211 includes a top wall 2111, a bottom wall 2112, and two first side walls 2113 and two second side walls 2114 disposed between the top wall 2111 and the bottom wall 2112. The top wall 2111, bottom wall 2112, two first side walls 2113, and two second side walls 2114 together form an accommodating space. The top wall 2111 and bottom wall 2112 are arranged opposite each other along the height direction of the outer casing 211. After the battery cell 21 is installed in the electrical device, the top wall 2111 is located above the bottom wall 2112, or the bottom wall 2112 is located above the top wall 2111. The second side wall 2114 can be referred to as the large surface of the battery cell 21. In the battery device 100, multiple battery cells 21 are arranged in sequence, and the second sidewalls 2114 of adjacent battery cells 21 abut against each other.

[0116] The outer casing 211 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0117] Please refer to Figure 4 In some embodiments, the recess 2011a is provided on the top wall 2111, that is, the first wall 2011 is the top wall 2111; for example Figure 7 As shown, in some other embodiments, the recess 2011a is provided on the first sidewall 2113, that is, the first wall 2011 is the first sidewall 2111; as Figure 8 As shown, in some embodiments, the recess 2011a is provided on the bottom wall 2112, that is, the first wall 2011 is the bottom wall 2112. In other embodiments, the recess 2011a may also be provided on the second side wall 2114; in other embodiments, the recess 2011a may also be provided on at least two of the top wall 2111, the first side wall 2113, the second side wall 2114 and the bottom wall 2112.

[0118] In the battery cell 21 provided in this application embodiment, the recess 2011a can be provided in at least one of the top wall 2111, bottom wall 2112, first side wall 2113, and second side wall 2114, so that the outer casing 211 forms a region with a small pressure relief space in the recess 2011a, which facilitates the smooth and rapid flow of gas to the pressure relief mechanism 213. The position of the recess 2011a can be flexibly set.

[0119] Please refer to Figures 4 to 6 In some embodiments, the first wall 2011 is the top wall 2111, the recess 2011a and the body part 2011b are distributed along the length direction of the outer shell 211, and the pressure relief mechanism 213 is provided on the first side wall 2113.

[0120] In this embodiment, the length direction of the outer casing 211 is the first direction. A portion of the top wall 2111 forms a recess 2011a, that is, the top wall 2111 is a first wall 2011 with the recess 2011a. Specifically, a portion of the top wall 2111 is recessed towards the interior of the battery cell 21 relative to the rest of the top wall 2111 to form the recess 2011a, and the rest of the top wall 2111 is the body portion 2011b; during manufacturing, the portion of the top wall 2111 can be formed into the downwardly recessed recess 2011a by means of rolling, stamping, etc.

[0121] Optionally, along the length of the outer casing 211, a recess 2011a is provided in the middle of the top wall 2111.

[0122] The pressure relief mechanism 213 is located on the first side wall 2113, that is, the pressure relief mechanism 213 is located on one side of the outer shell 211 along its length direction, and the pressure relief mechanism 213 avoids the large surface of the outer shell.

[0123] In this embodiment, in the top wall 2111, the recess 2011a and the body portion 2011b are distributed along the length direction (X direction) of the outer shell 211. The cross-section perpendicular to the length direction of the top wall 2111 and the outer shell 211 and passing through the recess 2011a is the first cross-section. Therefore, both the first cross-section and the second cross-section are in a plane perpendicular to the length direction of the top wall 2111 and the outer shell 211 (i.e., the ZX plane), and the area of ​​the first cross-section is smaller than the area of ​​the second cross-section. That is to say, the area of ​​the ZX plane where the pressure relief mechanism 213 is located is larger than the area of ​​the ZX plane where the recess 2011a is located.

[0124] It is understood that the height of the first cross section is less than the height of the second cross section; optionally, the width of the first cross section can be equal to the width of the second cross section to reduce the manufacturing difficulty, or the width of the first cross section can be less than the width of the second cross section, further increasing the difference in the size of the pressure relief space between the recess 2011a and the body 2011b.

[0125] By setting the recess 2011a on the top wall 2111, the area of ​​the ZX plane where the pressure relief mechanism 213 is located is larger than the area of ​​the ZX plane where the recess 2011a is located; along the length direction of the outer shell 211, the pressure relief space at the pressure relief mechanism 213 is larger than the pressure relief space at the recess 2011a, so that the gas can flow quickly to the pressure relief mechanism 213 for pressure relief, thereby improving the reliability of the battery cell 21.

[0126] In some embodiments, the recess 2011a is located in the middle of the top wall 2111 along its length direction, and the battery cell 21 also includes two electrode terminals 214 with opposite polarities, which are disposed in the recess 2011a.

[0127] The recess 2011a is located in the middle of the top wall 2111 along its length (Y direction), and both electrode terminals 214 are provided in the recess 2011a. The electrode terminal 214 is a conductor that passes through the top wall 2111. One end of the electrode terminal 214 is located inside the battery cell 21, and the other end is located outside the battery cell 21. The other end of the electrode terminal 214 is used to connect to an external busbar component. By providing the two electrode terminals 214 in the recess 2011a, the electrode terminals 214 can be flush with or lower than the height of the body portion 2011b on the top wall 2111, thus concealing the electrode terminals 214 within the recess 2011a of the battery cell 21.

[0128] Optionally, the two electrode terminals 214 are disposed in the same recess; in other embodiments, the two electrode terminals may also be disposed in two separate recesses.

[0129] By adopting the above technical solution, the two electrode terminals 214 are disposed in the recess 2011a, which reduces the space occupied by the electrode terminals 214 and improves the space utilization of the battery device 100.

[0130] In some embodiments, the electrode terminal 214 does not extend beyond the body portion 2011b in the direction from the bottom wall 2112 to the top wall 2111. Thus, the electrode terminal 214 can be hidden in the recessed area of ​​the housing 211, further reducing the space occupied by the electrode terminal 214.

[0131] Please refer to Figure 3 and Figure 4 In some embodiments, the electrode assembly 212 includes two tabs 2121 with opposite polarities, at least a portion of which is disposed opposite to the body portion 2011b on the top wall 2111, and the two tabs 2121 are connected to two electrode terminals 214 in a one-to-one correspondence.

[0132] The electrode assembly 212 includes two tabs 2121, which are a positive tab 2121 and a negative tab 2121, respectively. At least a portion of the tab 2121 is disposed opposite to the body portion 2011b of the top wall 2111, so that at least a portion of the tab 2121 can be accommodated in the body portion 2011b, thereby reducing the space occupied by the tab 2121 and the electrode terminal 214 in the height direction (Z direction) of the battery cell 21.

[0133] Optionally, the tab 2121 can be connected to the corresponding electrode terminal 214 via an adapter.

[0134] By adopting the above technical solution, at least a portion of the two tabs 2121 of the electrode assembly 212 are arranged opposite to the body portion 2011b, reducing the space of the tabs 2121 and the electrode terminals 214 in the height direction of the battery cell 21, and further improving the space utilization of the battery device 100.

[0135] Please refer to Figures 4 to 6 In some embodiments, the battery device 100 further includes an insulating member 215 connected to the top wall 2111. The insulating member 215 includes an insulating body 2151 and a boss 2152. The insulating body 2151 is connected to the side of the top wall 2111 facing the receiving space. The boss 2152 is connected to the end of the insulating body near the pressure relief mechanism 213 and extends toward the receiving space. The boss 2152 is provided with a through hole 21521 for accessing the pressure relief mechanism 213.

[0136] The insulating element 215 can separate the top wall 2111 from the electrode assembly 212, reducing the risk of short circuit. For example, the insulating element 215 can be plastic, rubber, etc.

[0137] The insulating component 215 includes an insulating body 2151 and a boss 2152. The insulating body 2151 may be flat and is connected to the inner surface of the top wall 2111. The boss 2152 is connected to one end of the insulating body near the pressure relief mechanism 213. The boss 2152 has a through hole 21521 to allow gas generated by the electrode assembly 212 to flow from the through hole to the pressure relief mechanism 213. Optionally, the pressure relief mechanism 213 is located in the middle of the housing along its height direction. At least a portion of the pressure relief mechanism 213 is not blocked by the boss 2152, allowing some gas to flow directly from the electrode assembly 212 to the pressure relief mechanism 213.

[0138] By setting the insulating component 215, the risk of short circuit in the battery cell 21 is reduced; since the pressure relief mechanism 213 is located on one side of the housing along its length, the through hole 21521 on the boss 2152 allows gas to flow through, so that the gas can flow smoothly to the pressure relief mechanism 213 for pressure relief.

[0139] Please refer to Figure 7In some embodiments, the first wall 2011 is a first side wall 2112, and the pressure relief mechanism 213 is provided on the top wall 2111; the recess 2011a and the body part 2011b are distributed on the first side wall 2112 along the height direction of the outer shell 211, and the recess 2011a is provided on the side of the body part 2011b away from the top wall 2111.

[0140] In this embodiment, the height direction of the outer shell 211 is the first direction, and the first sidewall 2113 is a first wall 2011 with a recess 2011a.

[0141] Two first sidewalls 2113 are arranged opposite each other along the length direction (Y direction) of the outer casing 211, and two second sidewalls 2114 are arranged opposite each other along the width direction (X direction) of the outer casing 211. The second sidewalls 2114 are generally referred to as the large surface of the battery cell 21. In the battery device 100, multiple battery cells 21 are arranged sequentially, and the second sidewalls 2114 of adjacent battery cells 21 abut against each other. In this embodiment, the recess 2011a is provided on the first sidewall 2113, which does not affect the abutment between the battery cell 21 and the adjacent battery cell 21.

[0142] On the first sidewall 2113, a recess 2011a is provided on the side of the body portion 2011b away from the top wall 2111, so that the bottom of the battery cell 21 away from the pressure relief mechanism 213 has a smaller pressure relief space, and the top of the battery cell 21 has a larger pressure relief space.

[0143] In this embodiment, the recess 2011a and the body portion 2011b are distributed along the height direction (Z direction) of the outer shell on the first sidewall 2113, which is the first wall 2011 with the recess 2011a. Let the cross-section perpendicular to the height direction of the first wall 2011 and the outer shell 211 and passing through the recess 2011a be the first cross-section, and let the cross-section perpendicular to the height direction of the first wall 2011 and the outer shell 211 and passing through the pressure relief mechanism 213 be the second cross-section. Both the first and second cross-sections are cross-sections of the outer shell 211 along the XY direction, and the area of ​​the first cross-section is smaller than the area of ​​the second cross-section. That is, the area of ​​the XY plane where the pressure relief mechanism 213 is located is larger than the area of ​​the XY plane where the recess 2011a is located.

[0144] By providing the recess 2011a on the first side wall 2113 of the housing 211 and the pressure relief mechanism 213 on the top wall 2111, the pressure relief space at the pressure relief mechanism 213 is greater than the pressure relief space at the recess 2011a along the height direction of the housing 211; and, while improving the pressure relief stability, it does not affect the mutual support between the battery cell 21 and the adjacent battery cell 21.

[0145] In some embodiments, the first sidewall 2113 has an outwardly extending first protrusion located at one end of the first wall 2011 near the top wall 2111, and the remaining portion of the first sidewall 2113 is formed as a recess 2011a; the top wall 2111 has a second protrusion connected to the first protrusion.

[0146] By making the end of the first sidewall 2113 near the top wall 2111 into the body part 2011b, the manufacturing method of the outer shell 211 is relatively simple and the cost is low.

[0147] In some embodiments, each of the two first sidewalls 2113 is provided with a recess 2011a and a body portion 2011b.

[0148] The body portion 2011b on both first sidewalls 2113 is located at the end of the first sidewall 2113 near the end cap, so that the pressure relief mechanism 213 has a large pressure relief space.

[0149] By adopting the above technical solution, the pressure relief space at pressure relief mechanism 213 is further increased, and the pressure relief speed is improved.

[0150] In some embodiments, the recesses 2011a on the two first sidewalls 2113 are positioned opposite each other.

[0151] Both first sidewalls 2113 have outwardly extending first protrusions, and the first protrusions on the two first sidewalls 2113 are arranged opposite each other. The portion of the first sidewall 2113 outside the first protrusions is formed as a recess 2011a, and the recesses 2011a on the two first sidewalls 2113 are arranged opposite each other. The two ends of the top wall 2111 along its length direction are respectively connected to the two first protrusions.

[0152] By adopting the above technical solution, the pressure relief spaces on both sides of the outer casing 211 along its length direction are symmetrically arranged, which is conducive to the uniform flow of gas on both sides of the outer casing 211.

[0153] Please continue to refer to Figure 7 In some embodiments, the size of the body portion 2011b is smaller than the size of the recess 2011a along the height direction (Z direction) of the housing 211.

[0154] The size of the main body 2011b is smaller than the size of the recess 2011a. For example, the size of the main body 2011b is 1 / 10 to 1 / 2 of the size of the recess 2011a. The specific size can be set according to parameters such as pressure relief requirements, the size of the battery cell 21, and the capacity of the battery device 100.

[0155] The recess 2011a is located on the side of the body portion 2011b away from the top wall 2111, that is, the body portion 2011b is connected to the top wall 2111. The end of the battery cell 21 near the top wall 2111 has a larger pressure relief space, which improves the reliability of pressure relief. The size of the body portion 2011b is smaller than the size of the recess 2011a, which can improve the space utilization of the battery device 100.

[0156] In other embodiments, the body portion 2011b may also be disposed at the middle of the first sidewall 2113 along its height direction; in other embodiments, the size of the body portion 2011b and the recess 2011a may be equal or the size of the body portion 2011b may be larger than the size of the recess 2011a.

[0157] Please refer to Figure 8 In some embodiments, electrode terminals 214 are disposed on top wall 2111, first wall 2011 is bottom wall 2112, recesses 2011a and body portion 2011b are distributed on bottom wall 2112 along the width direction of outer shell 211; pressure relief mechanism 213 is disposed on bottom wall 2112 and located on body portion 2011b, and the area of ​​the cross-section of outer shell 211 through pressure relief mechanism 213 along its height and length directions is greater than the area of ​​second side wall 2114.

[0158] If a recess 2011a is provided on the bottom wall 2112, then the bottom wall 2112 is the first wall 2011. The bottom wall 2112, the first side wall 2113 and the second side wall 2114 can be integrally connected, or the bottom wall 2112 can also be connected to the first side wall 2113 and the second side wall 2114 by welding or other means.

[0159] like Figure 8 As shown, the bottom wall 2112 is provided with an outwardly protruding structure; on the bottom wall 2112, the protruding structure is formed as the body part 2011b and the rest of the bottom wall 2112 is formed as the body part 2011b, and the pressure relief mechanism 213 is provided on the protruding structure.

[0160] The cross-section of the outer shell 211 along its height and length directions through the pressure relief mechanism 213 is the second cross-section, and the cross-section of the outer shell 211 along its height and length directions through the recess 2011a is the first cross-section. The area of ​​the first cross-section is equal to the area of ​​the second side wall 2114. Therefore, the area of ​​the cross-section of the outer shell 211 along its height and length directions through the pressure relief mechanism 213 is greater than the area of ​​the second side wall 2114.

[0161] By adopting the above technical solution, the area of ​​the ZY plane where the pressure relief mechanism 213 is located is larger than the area of ​​the ZY plane where the recess 2011a is located (the plane area of ​​the large surface of the outer shell). Along the width direction of the outer shell 211, the pressure relief space at the pressure relief mechanism 213 is larger than the pressure relief space at the recess. This facilitates the rapid flow of gas from the pressure relief space corresponding to the recess 2011a to the pressure relief mechanism 213, thereby improving the reliability of pressure relief and the reliability of the battery cell 21.

[0162] In some embodiments, a recess 2011a surrounds the body portion 2011b on the bottom wall 2112.

[0163] The recess 2011a surrounds the body portion 2011b, meaning that within the plane of the bottom wall 2112, the body portion 2011b is provided with recesses 2011a on all sides. The body portion 2011b is located in the central region of the bottom wall 2112, and the recesses 2011a constitute the edge region of the bottom wall 2112. Thus, the recesses 2011a and the body portion 2011b are simultaneously distributed on the bottom wall 2112 along a first preset direction and a second preset direction. The first preset direction is the width direction (X direction) of the outer shell 211, and the second preset direction is the length direction (Y direction) of the outer shell 211.

[0164] In the outer casing 211, a cross section perpendicular to the first wall 2011 and the first preset direction and passing through the recess 2011a is designated as the first cross section, and a cross section perpendicular to the first wall 2011 and the first preset direction and passing through the body portion 2011b is designated as the second cross section. The area of ​​the first cross section is smaller than the area of ​​the second cross section.

[0165] In the outer casing 211, a cross section perpendicular to the first wall 2011 and the second preset direction and passing through the recess 2011a is designated as a third cross section, and a cross section perpendicular to the first wall 2011 and the second preset direction and passing through the body portion 2011b is designated as a fourth cross section. The area of ​​the third cross section is smaller than the area of ​​the fourth cross section.

[0166] By adopting the above technical solution, the area of ​​the ZY plane where the main body 2011b is located is larger than the area of ​​the ZY plane where the recess 2011a is located. At the same time, the area of ​​the ZX plane where the main body 2011b is located is larger than the area of ​​the ZX plane where the recess 2011a is located. Thus, along the length and width directions of the outer shell 211, the pressure relief space at the pressure relief mechanism 213 is larger than the pressure relief space at the recess 2011a, further improving the reliability of pressure relief and the reliability of the battery cell 21.

[0167] In some embodiments, the bottom wall 2112, the two first side walls 2113 and the two second side walls 2114 are integrally formed to form a shell, and an opening is formed at one end of the shell away from the bottom wall 2112, and the top wall 2111 covers the opening.

[0168] The top wall 2111 can also be called the end cap. An opening is formed on one side of the shell, and the end cap is closed over the opening.

[0169] By setting up a housing and a top wall 2111 connected to the housing, the processing efficiency of the outer shell 211 can be improved.

[0170] like Figure 4 As shown, in some embodiments, the recess 2011a is provided on the top wall 2111. Since the top wall 2111 can be manufactured separately, the manufacturing difficulty of the recess 2011a is reduced, and the manufacturing efficiency is improved. Figure 7 As shown, in some embodiments, both the pressure relief mechanism 213 and the electrode terminal 214 are located on the top wall 2111; as Figure 8 As shown, in some embodiments, electrode terminals (not shown) are provided on the top wall 2111, and the recess 2011a and the pressure relief mechanism 213 are both provided on the bottom wall 2112.

[0171] Please refer to Figures 3 to 8 Some embodiments of this application provide a battery cell 21, including a housing 211, an electrode assembly 212, and a pressure relief mechanism 213. The housing 211 has a receiving space, and the electrode assembly 212 is disposed within the receiving space. The pressure relief mechanism 213 is disposed on the housing 211 and is used to release the internal pressure of the battery cell 21. The housing 211 includes a first wall 2011, which has a recess 2011a and a body portion 2011b distributed along a first direction. The recess 2011a is recessed relative to the body portion 2011b in the direction toward the receiving space. The housing 211 has a first shell portion 211a and a second shell portion 211b distributed along the first direction. The recess 2011a is disposed in the first shell portion 211a, the body portion 2011b is disposed in the second shell portion 211b, and the pressure relief mechanism 213 is at least partially disposed in the second shell portion 211b.

[0172] The battery cell 21 provided in this embodiment has a recess 2011a on the first wall 2011 of the outer casing 211, so that the pressure relief space formed by the first casing portion 211a is smaller than the pressure relief space formed by the second casing portion 211b. Since the pressure relief mechanism 213 is at least partially provided in the second casing portion 211b, when the internal pressure or temperature of the battery cell 21 reaches a threshold, the gas inside the battery cell 21 can flow rapidly from the gas-generating area to the pressure relief mechanism 213, shortening the time for the gas to reach the pressure relief mechanism 213, reducing the gas pressure at the gas-generating location, improving the timeliness of pressure relief, thereby reducing the risk of the battery cell 21 exploding due to untimely pressure relief or excessive pressure, and improving the reliability of the battery cell 21.

[0173] The second aspect of this application provides a battery device 100, including a battery cell 21 as provided in the first aspect.

[0174] A third aspect of this application provides an energy storage device, such as the battery cell 21 of the first aspect or the battery device 100 of the second aspect, wherein the battery cell 21 or the battery device 100 is used to store or provide electrical energy.

[0175] The fourth aspect of this application provides an electrical device, including a battery cell 21 as in the first aspect, a battery device 100 as in the second aspect, or an energy storage device as in the third aspect.

[0176] The power supply device can be any of the aforementioned devices or systems that utilize battery device 100.

[0177] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, include: An outer casing, wherein an accommodating space is provided inside the outer casing; An electrode assembly is disposed within the accommodating space; A pressure relief mechanism is provided on the outer casing, and the pressure relief mechanism is used to release the internal pressure of the battery cell. The outer casing includes a first wall having a recess and a body portion distributed along a first direction, the recess being recessed relative to the body portion toward the receiving space; The outer casing has a first housing portion and a second housing portion distributed along the first direction, the recess is provided in the first housing portion, the body portion is provided in the second housing portion, and the pressure relief mechanism is at least partially provided in the second housing portion.

2. The battery cell of claim 1, wherein, In the outer casing, a first cross-section is defined as the cross-section perpendicular to the first wall and the first direction and passing through the recess, and a second cross-section is defined as the cross-section perpendicular to the first wall and the first direction and passing through the body portion, wherein the area of ​​the first cross-section is smaller than the area of ​​the second cross-section.

3. The battery cell of claim 1, wherein, The height of the body portion extending beyond the recess is H, where 2mm ≤ H ≤ 10mm.

4. The battery cell of any one of claims 1-3, wherein, The outer casing includes a top wall and a bottom wall disposed opposite to each other, and two first side walls and two second side walls disposed between the top wall and the bottom wall, wherein the second side walls are the walls with the largest area in the outer casing; the top wall and the bottom wall are disposed opposite to each other along the height direction of the outer casing, the two first side walls are disposed opposite to each other along the length direction of the outer casing, and the two second side walls are disposed opposite to each other along the width direction of the outer casing; The first wall is the top wall, the bottom wall, the first side wall, or the second side wall.

5. The battery cell of claim 4, wherein the cathode comprises a lithium metal oxide. The first wall is the top wall, and the recess and the main body are distributed along the length of the outer shell; the pressure relief mechanism is provided on the first side wall.

6. The battery cell of claim 5, wherein, The recess is located in the middle of the top wall along its length, and the battery cell also includes two electrode terminals with opposite polarities, which are disposed in the recess.

7. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. Along the direction from the bottom wall to the top wall, the electrode terminals do not extend beyond the body portion.

8. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. The electrode assembly includes two tabs of opposite polarity, at least a portion of which is disposed opposite to the body portion on the top wall, and the two tabs are connected to the two electrode terminals one-to-one.

9. The battery cell of claim 8, wherein the cathode comprises a lithium metal oxide. The battery cell also includes an insulating component connected to the top wall. The insulating component includes an insulating body and a boss. The insulating body is connected to the side of the top wall facing the receiving space. The boss is connected to the end of the insulating body near the pressure relief mechanism and extends toward the receiving space. The boss is provided with a through hole for accessing the pressure relief mechanism.

10. The battery cell of claim 4, wherein the cathode comprises a lithium metal oxide. The first wall is the first side wall, and the pressure relief mechanism is located on the top wall; The recess and the body portion are distributed on the first sidewall along the height direction of the outer shell, and the recess is located on the side of the body portion away from the top wall.

11. The battery cell of claim 10, wherein the cathode comprises a lithium metal oxide. The first sidewall has an outwardly extending first protrusion located at one end of the first sidewall near the top wall, and the remaining portion of the first sidewall is formed as the recess; the top wall has a second protrusion connected to the first protrusion.

12. The battery cell as described in claim 10, characterized in that, The recess and the main body are provided on both of the first sidewalls.

13. The battery cell as described in claim 12, characterized in that, The two recesses on the first sidewalls are positioned opposite each other.

14. The battery cell as described in claim 10, characterized in that, Along the height direction of the outer shell, the size of the body portion is smaller than the size of the recess.

15. The battery cell as described in claim 4, characterized in that, The battery cell also includes two electrode terminals with opposite polarities, the electrode terminals are disposed on the top wall, the first wall is the bottom wall, and the recess and the body portion are distributed on the bottom wall along the width direction of the outer shell; The pressure relief mechanism is located on the bottom wall and in the main body. The cross-sectional area of ​​the outer shell through the pressure relief mechanism along its height and length directions is greater than the area of ​​the second side wall.

16. The battery cell of claim 15, wherein, On the bottom wall, the recess surrounds the body portion.

17. The battery cell as described in claim 4, characterized in that, The bottom wall, the two first side walls, and the two second side walls are integrally formed to form a shell. An opening is formed at one end of the shell opposite to the bottom wall, and the top wall covers the opening.

18. A battery device, characterized by Includes the battery cell as described in any one of claims 1-17.

19. An energy storage device, characterized by, Includes a battery cell as described in any one of claims 1-17 or a battery device as described in claim 18, wherein the battery cell or battery device is used to store or provide electrical energy.

20. An electrical device, comprising: It includes the battery cell as described in any one of claims 1-17, the battery device as described in claim 18, or the energy storage device as described in claim 19.

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