Battery monomer, battery device and electric equipment

Abstract

The utility model discloses a battery monomer, a battery device and electric equipment. A battery cell includes a case, an electrode assembly, and a cap assembly. The housing has an opening. The electrode assembly is housed within the case. The cover assembly comprises a cover main body and a first convex part, the cover main body is connected to the shell and covers the opening, the cover main body is provided with a first surface facing the electrode assembly, and the first convex part is arranged at the end of the cover main body in the first direction and protrudes out of the first surface in the direction close to the electrode assembly. A first concave part is formed on the side, facing the electrode assembly, of the first convex part, the first convex part comprises a first wall part and a second wall part which are oppositely arranged in the first direction, and the first concave part is located between the first wall part and the second wall part. The first wall part or the second wall part can generate a limiting effect on the pole piece which tends to move outwards along the first direction, so that the pole piece is favorably limited in the first concave part, the risk of internal short circuit caused by moving outwards of the pole piece is reduced, and the reliability of the single battery is improved.

Description

Technical Field

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

[0002] With the development of new energy technologies, batteries are being used more and more widely. For example, batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in military equipment and aerospace and many other fields.

[0003] The development of battery technology must take into account multiple design factors, such as energy density, cycle life, assembly efficiency, and processing technology, as well as battery reliability. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical appliance, which are beneficial for improving reliability.

[0005] According to a first aspect of this application, a battery cell is provided, comprising a housing, an electrode assembly, and a cover assembly. The housing has an opening. The electrode assembly is housed within the housing. The cover assembly includes a cover body and a first protrusion. The cover body is connected to the housing and covers the opening. The cover body has a first surface facing the electrode assembly. The first protrusion is located at the end of the cover body along a first direction and protrudes from the first surface toward the electrode assembly. A first recess is formed on the side of the first protrusion facing the electrode assembly. The first protrusion includes a first wall portion and a second wall portion disposed opposite each other along the first direction. The first recess is located between the first wall portion and the second wall portion. The first recess provides clearance space for the outer electrode plates and separators of the electrode assembly, reducing the risk of the first protrusion damaging the outer electrode plates and separators. The outermost of the first wall and the second wall can restrict the electrode plates with an outward tendency along the first direction, which helps to confine the electrode plates inside the first recess, reducing the risk of electrode plate outward movement leading to internal short circuits and improving the reliability of the battery cell.

[0006] In some embodiments, the first wall portion is located outside the second wall portion along the first direction, and the first wall portion forms part of the wall portion surrounding the first recess, while the second wall portion abuts against the electrode assembly. The first recess portion is closer to the outer side of the cover body along the first direction, which helps to provide clearance space for the outer electrode plates and spacers of the electrode assembly, reducing the risk of the electrode plates and spacers being crushed.

[0007] In some embodiments, a portion of the second wall extends beyond the first wall in the direction of proximity to the electrode assembly along the thickness direction of the cover body, and the thickness direction of the cover body is perpendicular to the first direction of the cover body. This reduces the likelihood of the first wall abutting against the electrode assembly while the second wall abuts against it, thus mitigating the squeezing effect of the first wall on the outer ring electrode and spacer of the electrode assembly, and further reducing the possibility of damage to the outer ring electrode and spacer.

[0008] In some embodiments, the first wall portion has a second surface facing the first recess, located on the outer side of the electrode assembly opposite to its center along the first direction. The first wall does not exert pressure on the electrode assembly, further reducing the possibility of the first wall damaging the outer electrode plates and separators of the electrode assembly. The first wall does not obstruct the electrode assembly along the first direction, does not affect the expansion and deformation of the electrode assembly, and helps reduce the risk of stress concentration in the electrode assembly, reducing lithium plating, increasing the capacity of the battery cell, and improving its cycle performance.

[0009] In some embodiments, the first wall portion includes a main body portion and a thinned portion connected to the main body portion, the thinned portion being located on the side of the main body portion closer to the electrode assembly; along a first direction, the thickness of the thinned portion is less than the thickness of the main body portion, and the thickness of the thinned portion is less than the thickness of the second wall portion; the thinned portion forms part of the wall portion surrounding the first recess. This not only helps to limit the outward movement of the electrode sheet and the spacer, but also reduces the thickness of the thinned portion in the first direction and increases the size of the first recess in the first direction, which helps to reduce the possibility of the thinned portion contacting the electrode assembly, thereby reducing the risk of the first wall damaging the electrode sheet and the spacer.

[0010] In some embodiments, the thickness of the thinned portion along the first direction is d1, where 0.5 mm ≤ d1 ≤ 1 mm. This reduces both the risk of breakage of the thinned portion and the risk of damage to the outer electrode and separator caused by the first wall.

[0011] In some embodiments, the first recess extends through the first protrusion along a second direction, which is perpendicular to the first direction. The first recess can form an exhaust channel extending through the first protrusion along the second direction, which facilitates the smooth discharge of gas within the first recess and reduces the risk of thermal runaway due to heat accumulation.

[0012] In some embodiments, the first protrusion includes a third wall portion connected between the first wall portion and the second wall portion, the first wall portion, the second wall portion, and the third wall portion forming a first recess; along a first direction, the thickness of the first wall portion is less than the thickness of the second wall portion. This improves the overall strength of the first protrusion and reduces the likelihood of the thinner first wall portion breaking. The relatively thicker second wall portion increases the area of ​​the first protrusion that abuts against the electrode assembly, thereby improving the limiting effect of the first protrusion on the electrode assembly.

[0013] In some embodiments, the first protrusion includes a third wall portion connected between the first wall portion and the second wall portion; the third wall portion includes a first part, a second part, and a third part, the first part being connected to the first wall portion, the third part being connected to the second wall portion, the third part being located on the side of the first part closer to the electrode assembly and capable of abutting against the electrode assembly, and the second part being connected between the first part and the third part; the first wall portion and the third wall portion together form a first recess. Thus, both forming a first recess between the third wall portion and the first wall portion and increasing the area of ​​the first protrusion for abutting against the electrode assembly can improve the limiting effect of the first protrusion on the electrode assembly.

[0014] In some embodiments, there are two first protrusions, each located at one end of the cover body along a first direction; a first gap is formed between the cover body and the electrode assembly, and the first gap is located between the two first protrusions along the first direction; a third portion is provided with a first through hole, which penetrates the third portion along the thickness direction of the cover body; the first protrusion is provided with a channel, which connects the first gap and the first through hole. Gas in the gap between the electrode and the insulating member that abuts against the third portion can flow to the first gap through the first through hole and the channel, and then act on the pressure relief mechanism through the first gap or flow to other spaces connected to the first gap before acting on the pressure relief mechanism. This facilitates the smooth discharge of gas inside the electrode assembly and reduces the risk of thermal runaway caused by poor gas discharge.

[0015] In some embodiments, the first protrusion includes two fourth wall portions disposed opposite each other along a second direction. The fourth wall portions connect to the first, second, and third wall portions. The first, second, third, and fourth wall portions enclose and form a second recess, which forms at least a portion of a channel. The fourth wall portions, together with the first, second, and third wall portions, form an annular closed structure, which improves the overall strength of the first protrusion, reduces the risk of deformation and collapse, and enhances the limiting effect of the first protrusion on the electrode assembly. The second recess also forms at least a portion of the channel, providing a larger buffer space for gas and helping to alleviate gas pressure.

[0016] In some embodiments, the second wall portion is provided with a second through hole, which extends through the second wall portion along a first direction. The channel includes a second recess and a second through hole, which is beneficial for shortening the gas flow path and reducing gas flow resistance; and / or, the fourth wall portion is provided with a third through hole, which extends through the fourth wall portion along a second direction. The channel includes a second recess and a third through hole.

[0017] In some embodiments, the outer diameter of the second through hole is 0.4mm-1.8mm, which facilitates the smooth discharge of gas inside the electrode assembly through the second through hole, maintains the overall strength of the second wall portion, reduces the risk of deformation or collapse, and improves the limiting effect of the first protrusion on the electrode assembly; and / or, the outer diameter of the third through hole is 0.4mm-1.8mm, which facilitates the smooth discharge of gas inside the electrode assembly through the third through hole, maintains the overall strength of the fourth wall portion, reduces the risk of deformation or collapse, and improves the limiting effect of the first protrusion on the electrode assembly.

[0018] In some embodiments, the outer diameter of the first through hole is 0.4mm-1.8mm. This facilitates the smooth discharge of gas inside the electrode assembly through the first through hole, maintains the overall strength of the third part, reduces the risk of deformation or collapse, and improves the limiting effect of the first protrusion on the electrode assembly.

[0019] In some embodiments, along the first direction, the size of the first recess is w, 1mm≤w≤3mm, which can achieve a balance between reducing the risk of the first protrusion damaging the outer ring electrode and the separator and improving the limiting effect of the first protrusion on the electrode assembly; and / or, along the thickness direction of the cover body, the size of the first recess is h, 3.5mm≤h≤6mm, which can achieve a balance between the overall strength of the first protrusion and reducing the risk of damaging the outer ring electrode and the separator.

[0020] In some embodiments, there are two first protrusions, each located at one end of the cover body along a first direction. The cover assembly also includes a second protrusion protruding from the first surface towards the electrode assembly, located between the two first protrusions and abutting against the electrode assembly. The two first protrusions can make the electrode assembly more evenly stressed, reduce stress concentration, and improve the stability of the electrode assembly. The second protrusion can also increase the overall strength of the cover assembly, reduce the risk of deformation and collapse of the cover assembly, and improve structural stability.

[0021] In some embodiments, the cover body includes a first cover portion and a second cover portion. The first cover portion closes onto the opening, and the second cover portion is disposed on the side of the first cover portion facing the electrode assembly. The first surface is the surface of the second cover portion facing the electrode assembly, and the first protrusion is disposed at the end of the second cover portion along a first direction of the cover body. This not only improves the overall structural strength of the cover body but also achieves insulation isolation between the cover body and the electrode assembly.

[0022] According to a second aspect of this application, embodiments of this application also provide a battery device comprising a plurality of battery cells provided according to any embodiment of the first aspect of this application.

[0023] According to a third aspect of this application, embodiments of this application also provide an electrical device that includes a battery device provided according to any embodiment of a second aspect of this application, the battery device being used to provide electrical energy. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 These are schematic diagrams of the vehicle structure provided in some embodiments of this application.

[0026] Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application.

[0027] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application.

[0028] Figure 4 This is a schematic diagram of the winding structure of the electrode assembly of a battery cell provided in some embodiments of this application.

[0029] Figure 5 This is a cross-sectional structural diagram of a battery cell provided in some embodiments of this application.

[0030] Figure 6 yes Figure 5 A magnified structural diagram of region A in the middle.

[0031] Figure 7 This is a cross-sectional schematic diagram of a partial structure of a battery cell provided in some other embodiments of this application.

[0032] Figure 8 This is a cross-sectional schematic diagram of a partial structure of a battery cell provided in some embodiments of this application.

[0033] Figure 9 This is an exploded structural diagram of the cover assembly of a battery cell provided in some embodiments of this application.

[0034] Figure 10 yes Figure 9 A magnified structural diagram of region B in the middle.

[0035] In the attached image:

[0036] Vehicle 1, battery pack 2, controller 3, motor 4, housing 5, battery cell 6;

[0037] Electrode assembly 10, positive electrode 11, negative electrode 12, separator 13, housing 20, opening 21, cover assembly 30, cover body 31, first cover portion 311, pressure relief hole 3111, second cover portion 312, first surface 312a, first protrusion 32, first wall portion 321, main body portion 3211, thinned portion 3212, second surface 321a, extended surface 321a′, second wall portion 322, second passage Hole 3221, third wall portion 323, first part 3231, second part 3232, third part 3233, first through hole 3234, fourth wall portion 324, third through hole 3241, first recess 33, second recess 34, second protrusion 35, electrode terminal 40, fourth wall portion 424, first gap 51, channel 52, first housing portion 5a, second housing portion 5b, accommodating space 5c, pressure relief mechanism 60;

[0038] First direction X, second direction Y, thickness direction Z, bisecting plane S. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0041] In this application, the reference to "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 in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0042] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0043] 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, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0044] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0045] In this application, "multiple" means two or more (including two).

[0046] In the embodiments of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.

[0047] In this embodiment of the application, the battery cell can be a secondary battery cell, which refers to a battery cell that can be used again after being discharged by recharging to activate the active materials.

[0048] The battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., but the embodiments of this application are not limited to this.

[0049] A typical battery cell includes an electrode assembly, a housing, and electrode terminals. The electrode assembly is housed within the housing, and the electrode terminals are located within the housing. The housing encapsulates the electrode assembly and electrolyte components. The electrode assembly includes tabs, which are electrically connected to the electrode terminals via adapters or directly to the electrode terminals. The electrode terminals are used to electrically connect the electrode assembly to external circuitry within the battery cell to enable charging or discharging of the battery cell.

[0050] The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0051] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0052] In some embodiments, the negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0053] In some implementations, the separator is positioned between the positive and negative electrodes.

[0054] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0055] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0056] In some embodiments, the electrode assembly is a wound structure or a stacked structure.

[0057] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0058] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0059] A battery device typically includes a housing for encapsulating one or more individual battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the individual battery cells.

[0060] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into an independent module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties. The battery cell assembly can be housed within a housing by fixing the battery module within the housing. As an example, the housing can include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, creating a closed space inside the housing to house the battery cell assembly.

[0061] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0062] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0063] The end cap of a battery cell typically has an insulating component on the side facing the electrode assembly to insulate and isolate the end cap from the electrode assembly. The insulating component has protrusions at both ends along the length of the end cap, which abut against the electrode assembly to limit its movement and reduce its wobbling.

[0064] For electrode assemblies with a wound structure, a spiral upward phenomenon may occur during the electrode winding process, resulting in a relatively high height for the outermost electrode and separator. Under conditions of vibration or other factors, the electrode assembly may experience relative displacement relative to the casing. This can lead to the outermost electrode and separator being easily damaged by the protrusions of the insulating components. To address this issue, recesses can be provided on the protrusions to avoid the electrode and separator at the protrusions. However, the outermost electrode and separator of the electrode assembly are relatively loose. Under conditions of vibration in the battery cell, the outermost electrode can easily shift towards the casing, causing an internal short circuit, which can lead to thermal runaway and affect the reliability of the battery cell.

[0065] In view of this, this application provides a technical solution by providing a first protrusion protruding towards the electrode assembly at the end of the cover assembly in a first direction, and providing a first recess on the side of the first protrusion facing the electrode assembly. The first recess can provide clearance space for the outer electrode sheet and separator of the electrode assembly, reducing the risk of the first protrusion damaging the outer electrode sheet and separator. Furthermore, the first protrusion includes a first wall portion and a second wall portion disposed opposite to each other in the first direction, and the first recess is located between the first wall portion and the second wall portion. The first wall portion or the second wall portion can restrict the electrode sheet with an outward tendency in the first direction, which is beneficial for confining the electrode sheet within the first recess, reducing the risk of the electrode sheet moving outward and causing an internal short circuit, and improving the reliability of the battery cell.

[0066] The technical solutions provided in this application are applicable to battery cells, battery devices, and electrical equipment using battery devices.

[0067] 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. The electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0068] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0069] Figure 1 This is a structural schematic diagram of a vehicle provided in some embodiments of this application. (Refer to...) Figure 1 Vehicle 1 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 2 is installed inside vehicle 1, and the battery device 2 can be located at the bottom, front, or rear of vehicle 1. The battery device 2 can be used to power vehicle 1; for example, the battery device 2 can serve as the operating power source for vehicle 1. Vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, to meet the power needs of vehicle 1 during starting, navigation, and driving.

[0070] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0071] Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application. (Refer to...) Figure 2The battery device 2 includes a housing 5 and battery cells 6, with the battery cells 6 housed within the housing 5. The housing 5 provides a accommodating space 5c for the battery cells 6, and the housing 5 can employ various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, together defining the accommodating space 5c for accommodating the battery cells 6. The second housing portion 5b may be a hollow structure with one open end, while the first housing portion 5a may be a plate-like structure, covering the open side of the second housing portion 5b so that the first housing portion 5a and the second housing portion 5b together define the accommodating space; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one open side, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b. Of course, the box 5 formed by the first box part 5a and the second box part 5b can be of various shapes, such as a cylinder, a cuboid, etc.

[0072] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0073] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0074] In the battery device 2, there can be multiple battery cells 6, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 6 are connected in both series and parallel configurations. Multiple battery cells 6 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 6 is housed within the housing 5. Alternatively, the battery device 2 can also consist of multiple battery cells 6 first connected in series, parallel, or in a mixed manner to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 5. The battery device 2 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 6.

[0075] For example, the battery cell 6 may be the smallest unit that makes up the battery device 2.

[0076] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application. (Refer to...) Figure 3 The battery cell 6 includes an electrode assembly 10, a housing 20, and a cover assembly 30.

[0077] The housing 20 is a hollow structure with an opening on one side. The cover assembly 30 covers the opening of the housing 20 and forms a sealed connection to form a cavity for accommodating the electrode assembly 10 and the electrolyte.

[0078] The shape of the housing 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cuboid structure, a cuboid housing can be selected.

[0079] In some embodiments, the cover assembly 30 includes an end cap that closes onto the opening of the housing 20. The end cap can have various structures; for example, it can be a plate-like structure, a hollow structure with one open end, etc. Exemplarily, in... Figure 3 In the embodiment shown, the housing 20 has a cuboid structure and the end cap has a plate-like structure, which covers the top opening of the housing 20.

[0080] The end cap can be made of an insulating material (e.g., plastic) or a conductive material (e.g., metal). When the end cap is made of a conductive material, the cap assembly 30 also includes an insulating element located on the side of the end cap facing the electrode assembly 10 to insulate the end cap from the electrode assembly 10.

[0081] The housing 20 may be open at one end or open at both ends. For example, the housing 20 may be open at one end, and the cover assembly 30 may be one that covers the opening of the housing 20. As another example, the housing 20 may also be open at both ends, and two cover assemblies 30 may be provided, each covering one of the two openings of the housing 20.

[0082] In some embodiments, the battery cell 6 further includes an electrode terminal 40, which can be electrically connected to the electrode assembly 10 for outputting or inputting electrical energy into the battery cell 6.

[0083] In some embodiments, electrode terminals 40 are disposed on cover assembly 30. Exemplarily, housing 20 may be an open-end structure, and battery cell 6 includes a cover assembly 30 and two electrode terminals 40, both electrode terminals 40 being mounted on the cover assembly 30 and electrically connected to a positive electrode and a negative electrode, respectively. As another example, housing 20 may also be an open-end structure, and battery cell 6 includes two cover assemblies 30 and two electrode terminals 40, with the two electrode terminals 40 respectively mounted on two cover assemblies 30.

[0084] In the battery cell 6, the electrode assembly 10 housed in the housing 20 can be one or more.

[0085] Figure 4 This is a schematic diagram of the winding structure of the electrode assembly of a battery cell according to some embodiments of this application. In some embodiments, the electrode assembly 10 has a winding structure. (Refer to...) Figure 4 The electrode assembly 10 includes a positive electrode 11, a negative electrode 12, and a separator 13. The positive electrode 11, negative electrode 12, and separator 13 are all strip-shaped structures. During winding, the positive electrode 11, separator 13, and negative electrode 12 can be stacked sequentially and wound more than two turns to form the electrode assembly 10. The electrode assembly 10 is flat. In preparing the electrode assembly 10, it can be directly wound into a flat shape, or it can be first wound into a hollow cylindrical structure and then flattened.

[0086] Figure 5 This is a cross-sectional structural diagram of a battery cell provided in some embodiments of this application. Figure 6 yes Figure 5 A magnified structural diagram of region A in the middle. Figure 7 This is a cross-sectional schematic diagram of a partial structure of a battery cell provided in some other embodiments of this application. Figure 8 This is a cross-sectional schematic diagram of a partial structure of a battery cell provided in some embodiments of this application. Figure 9 This is an exploded structural diagram of the cover assembly of a battery cell provided in some embodiments of this application. Figure 10 yes Figure 9 A magnified structural diagram of region B in the middle.

[0087] See Figures 5 to 10 The battery cell 6 provided in this application embodiment includes a housing 20, an electrode assembly 10, and a cover assembly 30. The housing 20 has an opening 21. The electrode assembly 10 is housed within the housing 20. The cover assembly 30 includes a cover body 31 and a first protrusion 32. The cover body 31 is connected to the housing 20 and covers the opening 21. The cover body 31 has a first surface 312a facing the electrode assembly 10. The first protrusion 32 is provided at the end of the cover body 31 along a first direction X, and the first protrusion 32 protrudes from the first surface 312a in a direction close to the electrode assembly 10. A first recess 33 is formed on the side of the first protrusion 32 facing the electrode assembly 10. The first protrusion 32 includes a first wall portion 321 and a second wall portion 322 disposed opposite to each other along the first direction X, and the first recess 33 is located between the first wall portion 321 and the second wall portion 322.

[0088] The cover body 31 can be connected to the shell 20 by welding, bonding, snap-fitting or other means.

[0089] In some embodiments, the cover body 31 is generally rectangular in shape. The cover body 31 has a length direction, a width direction, and a thickness direction, and the length direction, width direction, and thickness direction of the cover body 31 are perpendicular to each other. The thickness direction of the cover body 31 is parallel to the arrangement direction of the cover body 31 and the electrode assembly 10.

[0090] The first direction X is perpendicular to the thickness direction of the cover body 31. Optionally, the first direction X can be the length direction of the cover body 31. Alternatively, the first direction X can also be the width direction of the cover body 31.

[0091] The first surface 312a is the surface of the cover body 31 that directly faces the electrode assembly 10. In some examples, the cover body 31 is a one-piece molded component. Exemplarily, the cover body 31 may include a first cover portion 311, and the first surface 312a is the surface of the first cover portion 311 facing the electrode assembly 10. In other examples, the cover body 31 includes multiple independently molded components. Exemplarily, the cover body 31 may include a first cover portion 311 and a second cover portion 312, the second cover portion 312 being disposed on the side of the first cover portion 311 facing the electrode assembly 10, and the first surface 312a being the surface of the second cover portion 312 facing the electrode assembly 10.

[0092] The first protrusion 32 may be located entirely on the side of the cover body 31 facing the electrode assembly 10 and connected to the cover body 31. The first protrusion 32 and at least a portion thereof may be integrally formed, and the first protrusion 32 may also be connected to the cover body 31 in a suitable manner.

[0093] The first recess 33 may be recessed from the surface of the first protrusion 32 facing the electrode assembly 10 in a direction away from the electrode assembly 10. The recess depth of the first recess 33 may be less than or equal to the size of the first protrusion 32 protruding from the first surface 312a.

[0094] In some examples, refer to Figure 8 The first wall portion 321 and the second wall portion 322 form at least a portion of the wall portion surrounding the first recess 33. In other words, no other wall portions are provided between the first wall portion 321 and the first recess 33, or between the first recess 33 and the second wall portion 322, along the first direction X.

[0095] In other examples, refer to Figure 6 and Figure 7 One of the first wall portion 321 and the second wall portion 322 forms part of the wall portion surrounding the first recess 33, and the other is spaced apart from the first recess 33 along the first direction X. In other words, there is another wall portion between the first wall portion 321 and the second wall portion 322, which forms part of the wall portion surrounding the first recess 33.

[0096] The first recess 33 is closed at both ends along the first direction X, and the first recess 33 is open at least toward the electrode assembly 10. The first recess 33 may be open or closed on both sides along the second direction Y, and the second direction Y is perpendicular to the first direction X.

[0097] The first protrusion 32 protrudes toward the electrode assembly 10. The first protrusion 32 is closer to the electrode assembly 10 than the cover body 31. The first protrusion 32 can restrict the electrode assembly 10 along the thickness direction Z of the cover body 31 to reduce the shaking of the electrode assembly 10 relative to the housing 20 and improve the stability of the electrode assembly 10 relative to the housing 20.

[0098] The first recess 33 is formed on the first protrusion 32 along the thickness direction Z of the cover body 31. The projection of the first recess 33 overlaps with the projection of a portion of the outer ring electrode and the spacer of the electrode assembly 10. The first recess 33 is open towards the electrode assembly 10, providing clearance for the outer ring electrode and the spacer of the electrode assembly 10 and reducing the risk of the first protrusion 32 damaging the outer ring electrode and the spacer. In the embodiments of this application, the outer ring electrode and the spacer refer to a number of outer ring electrode and spacer rings away from the winding center.

[0099] The first recess 33 is located between the first wall portion 321 and the second wall portion 322, which are spaced apart along the first direction X. The outermost one of the first wall portion 321 and the second wall portion 322 can restrict the electrode sheet with the tendency to move outward along the first direction X. This helps to confine the electrode sheet to the inner side of the first recess 33, reduce the risk of the electrode sheet moving outward and causing an internal short circuit, and improve the reliability of the battery cell 6.

[0100] In some embodiments, a first wall portion 321 is disposed on the outer side of a second wall portion 322 along a first direction X, the first wall portion 321 forming part of a wall portion surrounding a first recess 33, and the second wall portion 322 abutting against an electrode assembly 10.

[0101] The cover body 31 has a bisecting plane S perpendicular to the first direction X. This bisecting plane S is located at the middle of the cover body 31 along the first direction X and can bisecte the cover body 31 along the first direction X. The outer side of the second wall portion 322 along the first direction X refers to the side of the second wall portion 322 that is away from the bisecting plane S along the first direction X. The first wall portion 321 is located on the side of the second wall portion 322 that is away from the bisecting plane S along the first direction X. Along the first direction X, the first wall portion 321 is further away from the bisecting plane S than the second wall portion 322.

[0102] Both the first wall portion 321 and the second wall portion 322 protrude from the first surface 312a in a direction close to the electrode assembly 10. The size of the first wall portion 321 protruding from the first surface 312a and the size of the second wall portion 322 protruding from the first surface 312a can be the same or different.

[0103] The outer surface of the first wall portion 321 along the first direction X can be flush with the outer end face of the cover body 31 along the first direction X. Alternatively, the outer surface of the first wall portion 321 can be located inside the outer end face of the cover body 31 along the first direction X.

[0104] In some examples, the projection of the first wall portion 321 along the thickness direction Z can at least partially overlap with the projection of the electrode assembly 10, and the first wall portion 321 can abut against the electrode assembly 10 along the thickness direction Z.

[0105] In other examples, along the thickness direction Z, the projection of the first wall portion 321 is separate from the projection of the electrode assembly 10, and the first wall portion 321 does not abut against the electrode assembly 10 along the thickness direction Z.

[0106] Along the thickness direction Z, the projection of the second wall portion 322 and the projection of the electrode assembly 10 at least partially overlap, and the second wall portion 322 can abut against the electrode assembly 10 along the thickness direction Z to reduce the shaking of the electrode assembly 10.

[0107] Along the first direction X, the second wall portion 322 is provided on the inner side of the first recess 33 near the center of the cover body 31 along the first direction X, and the first wall portion 321 is provided on the outer side of the first recess 33 away from the center of the cover body 31 along the first direction X. The first wall portion 321 can restrict the electrode and the separator that have the tendency to move outward along the first direction X, thereby restricting the electrode and the separator to the inner side of the first recess 33, which helps to reduce the risk of the electrode moving outward and causing internal short circuit, and improves the reliability of the battery cell 6.

[0108] When the electrode assembly 10 is spirally wound upwards, the outermost electrode plates and separators are higher and more easily damaged.

[0109] Therefore, in this embodiment, the first wall portion 321 forms part of the wall portion surrounding the first recess 33. The first recess 33 is closer to the outer side of the cover body 31 along the first direction X, which is beneficial to provide space for the electrode assembly 10 to be further outward of the electrode sheet and the separator, and reduces the risk of the electrode sheet and the separator being crushed.

[0110] In some embodiments, refer to Figure 7 Along the thickness direction Z of the cover body 31, a portion of the second wall portion 322 extends beyond the first wall portion 321 in a direction close to the electrode assembly 10, with the thickness direction Z, the first direction X, and the second direction Y being perpendicular to each other.

[0111] In other words, along the thickness direction Z of the cover body 31, the second wall portion 322 is closer to the electrode assembly 10 than the first wall portion 321. The size by which the second wall portion 322 protrudes from the first surface 312a can be larger than the size by which the first wall portion 321 protrudes from the first surface 312a. Therefore, while the second wall portion 322 abuts against the electrode assembly 10, the likelihood of the first wall portion 321 abutting against the electrode assembly 10 is reduced, which helps to alleviate the squeezing effect of the first wall portion 321 on the outer ring electrode and separator of the electrode assembly 10, further reducing the possibility of the outer ring electrode and separator being damaged.

[0112] In some embodiments, refer to Figure 7 The first wall portion 321 has a second surface 321a facing the first recess 33. Along the first direction X, the extension surface 321a′ of the second surface 321a in the thickness direction Z of the cover body 31 is located between the electrode assembly 10 and the housing 20.

[0113] The housing 20 has two shell walls disposed opposite each other along a first direction X. The extension surface 321a' of the second surface 321a in the thickness direction Z of the cover body 31 can be located between the shell wall adjacent to the first wall portion 321 and the electrode assembly 10. Along the thickness direction Z of the cover body 31, the projection of the first wall portion 321 and the projection of the electrode assembly 10 are opposite. Even if the electrode assembly 10 moves relative to the housing 20 toward the cover assembly 30, the first wall portion 321 will not exert a pressing force on the electrode assembly 10, which helps to further reduce the possibility of the first wall portion 321 crushing the outer electrode plate and the insulating member of the electrode assembly 10.

[0114] Furthermore, along the thickness direction Z of the cover body 31, the first wall portion 321 is further away from the electrode assembly 10 than the second wall portion 322. The first wall portion 321 does not obstruct the electrode assembly 10 along the first direction X, does not affect the expansion and deformation of the electrode assembly 10, and helps to reduce the risk of stress concentration in the electrode assembly 10, reduce lithium plating, increase the capacity of the battery cell 6, and improve its cycle performance.

[0115] In some embodiments, the first wall portion 321 includes a main body portion 3211 and a thinned portion 3212 connected to the main body portion 3211, the thinned portion 3212 being located on the side of the main body portion 3211 near the electrode assembly 10. Along the first direction X, the thickness of the thinned portion 3212 is less than the thickness of the main body portion 3211, and the thickness of the thinned portion 3212 is less than the thickness of the second wall portion 322. The thinned portion 3212 forms a portion of the wall portion surrounding the first recess 33.

[0116] Both the main body 3211 and the second wall 322 can be directly connected to the cover body 31, or they can be integrally formed with at least a part of the structure of the cover body 31.

[0117] The thicknesses of the main body portion 3211 and the second wall portion 322 can be the same or different. Optionally, the thickness of the main body portion 3211 can be greater than the thickness of the second wall portion 322 to compensate for the impact of the thinning of the thinned portion 3212 on the structural strength of the entire first wall portion 321.

[0118] The main body 3211 may form part of the wall portion surrounding the first recess 33, or it may not form part of the wall portion of the first recess 33.

[0119] The main body 3211 and the second wall 322 are relatively thick, making them less prone to deformation or breakage, which helps to improve the overall structural strength of the first protrusion 32.

[0120] The thinning portion 3212 forms part of the wall surrounding the first recess 33, and is used to restrict the electrode and separator that have an outward tendency to extend outward along the first direction X. The outer electrode and separator exert a smaller force on the thinning portion 3212, and the strength requirement for the thinning portion 3212 is smaller. Therefore, in this embodiment, the thickness of the thinning portion 3212 is set to be relatively small, which is beneficial to restrict the outward extension of the electrode and separator, and can also reduce the thickness of the thinning portion 3212 in the first direction X, increase the size of the first recess 33 in the first direction X, which is beneficial to reduce the possibility of the thinning portion 3212 contacting the electrode assembly 10, thereby reducing the risk of the first wall portion 321 damaging the electrode and separator.

[0121] In some embodiments, the thickness of the thinned portion 3212 along the first direction X is d1, where 0.5mm≤d1≤1mm.

[0122] Optionally, the thickness d1 of the thinned portion 3212 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, or any value between any two of these.

[0123] If the thickness of the thinned portion 3212 is too small, it is easy for it to break during assembly or when the battery cell vibrates. If the thickness of the thinned portion 3212 is too large, it occupies more space along the first direction X, which is not conducive to making way for the electrode and separator, and is easy to damage the outer electrode and separator.

[0124] In this embodiment, the thickness d1 of the thinning portion 3212 is set to 0.5mm-1mm, which is beneficial to reducing the risk of breakage of the thinning portion 3212 and also to reducing the risk of the outer electrode and the separator being damaged by the first wall portion 321.

[0125] In some embodiments, the first recess 33 penetrates the first protrusion 32 along the second direction Y.

[0126] In other words, the first recess 33 is not only open towards the electrode assembly 10 in the thickness direction Z, but also open to both sides in the second direction Y.

[0127] When a portion of the electrode and separator of the electrode assembly 10 are housed in the first recess 33 due to spiral winding or upward movement, gas between the electrode and separator tends to accumulate in the first recess 33 and is difficult to expel. Therefore, in this embodiment, the first recess 33 extends through the first protrusion 32, forming an exhaust channel along the second direction Y through the first protrusion 32. This facilitates the smooth discharge of gas from the first recess 33 and reduces the risk of thermal runaway due to heat accumulation. Furthermore, the fact that the first recess 33 extends through the first protrusion 32 further reduces the risk of the first protrusion 32 damaging the electrode or separator.

[0128] In some embodiments, refer to Figure 8 The first protrusion 32 includes a third wall portion 323, which connects the first wall portion 321 and the second wall portion 322. The first wall portion 321, the second wall portion 322, and the third wall portion 323 together form a first recess 33. Along the first direction X, the thickness of the first wall portion 321 is less than the thickness of the second wall portion 322.

[0129] The third wall portion 323 is a straight structure extending along the first direction X.

[0130] The third wall portion 323 connects the first wall portion 321 and the second wall portion 322, which helps to improve the overall strength of the first protrusion 32 and reduce the possibility of the thinner first wall portion 321 breaking. The second wall portion 322 is relatively thick, which can increase the area of ​​the first protrusion 32 that abuts against the electrode assembly 10, thereby improving the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0131] In some embodiments, refer to Figure 6 The first protrusion 32 includes a third wall portion 323, which connects the first wall portion 321 and the second wall portion 322. The third wall portion 323 includes a first part 3231, a second part 3232, and a third part 3233. The first part 3231 connects to the first wall portion 321, and the third part 3233 connects to the second wall portion 322. The third part 3233 is located on the side of the first part 3231 near the electrode assembly 10 and can abut against the electrode assembly 10. The second part 3232 connects the first part 3231 and the third part 3233. The first wall portion 321 and the third wall portion 323 together form a first recess 33.

[0132] The surface of the third part 3233 facing the electrode assembly 10 may be flush with the surface of the second wall part 322 facing the electrode assembly 10, so that they can jointly abut against the electrode assembly 10.

[0133] Both the third part 3233 and the first part 3231 can extend along the first direction X, and the second part 3232 can extend along the thickness direction Z. The two ends of the second part 3232 along the thickness direction Z are respectively connected to the first part 3231 and the third part 3233. The third wall portion 323 can be stepped.

[0134] The first part 3231 can form the bottom wall surrounding the first recess 33, and the second part 3232, a part of the third part 3233, and the thinning part 3212 respectively form the two side walls surrounding the first recess 33.

[0135] In this embodiment, a stepped third wall portion 323 is provided between the first wall portion 321 and the second wall portion 322. This not only forms a first recess 33 between the third wall portion 323 and the first wall portion 321, but also increases the area of ​​the first protrusion 32 that abuts against the electrode assembly 10, thereby improving the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0136] In some embodiments, along the first direction X, the distance between the first recess 33 and the surface of the second wall portion 322 facing away from the first wall portion 321 is 1-3 mm.

[0137] The distance between the surface of the first recess 33 and the surface of the second wall portion 322 facing away from the first wall portion 321 can be the sum of the dimensions of the second wall portion 322 and the third portion 3233 along the first direction X.

[0138] In some embodiments, there are two first protrusions 32, which are respectively located at both ends of the cover body 31 along the first direction X. A first gap 51 is formed between the cover body 31 and the electrode assembly 10, and the first gap 51 is located between the two first protrusions 32 along the first direction X. The third portion 3233 is provided with a first through hole 3234, which penetrates the third portion 3233 along the thickness direction Z of the cover body 31. The first protrusions 32 are provided with channels 52, which connect the first gap 51 and the first through hole 3234.

[0139] The first protrusion 32 can form part of the structure that encloses the first gap 51.

[0140] Optionally, there can be two first protrusions 32, which are located at the two ends of the cover body 31 along the first direction X. Along the first direction X, the first gap 51 can be located between the two first protrusions 32.

[0141] The first through hole 3234 can be one or more.

[0142] The channel 52 can have various structural forms, as long as it allows gas to flow. Optionally, the channel 52 may include a through hole, a cavity, a groove, or any combination of two or more thereof.

[0143] When the third part 3233 abuts against the electrode assembly 10, it will block part of the gas exhaust channel inside the electrode assembly 10. For example, the gas in the gap between the electrode and the insulating member that abuts against the third part 3233 will be blocked by the third part 3233, and the exhaust will be obstructed.

[0144] Therefore, in this embodiment, a first through hole 3234 is opened in the third part 3233, and a channel 52 is provided in the first protrusion 32. The gas in the gap between the electrode and the insulating member that abuts the third part 3233 can flow to the first gap 51 through the first through hole 3234 and the channel 52, and then act on the pressure relief mechanism through the first gap 51 or flow to other spaces connected to the first gap 51 and then act on the pressure relief mechanism. This is conducive to the smooth discharge of gas inside the electrode assembly 10 and reduces the risk of thermal runaway caused by poor gas discharge.

[0145] In some embodiments, the outer diameter of the first through hole 3234 is 0.4mm-1.8mm.

[0146] The shape of the first through hole 3234 can be circular, square, triangular or other suitable shape.

[0147] When the first through hole 3234 is a circular hole, its outer diameter is its diameter. When the first through hole 3234 is a non-circular hole, its outer diameter refers to the diameter of its circumcircle.

[0148] Optionally, the outer diameter of the first through hole 3234 can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, or any value between any two of these.

[0149] If the outer diameter of the first through hole 3234 is too small, it will create greater resistance to the gas and prevent the gas from flowing effectively; if the outer diameter of the first through hole 3234 is too large, it will affect the overall strength of the third part 3233, and thus affect the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0150] In this embodiment, the outer diameter of the first through hole 3234 is set to 0.4mm-1.8mm, which is beneficial for the smooth discharge of gas inside the electrode assembly 10 through the first through hole 3234, and also helps to maintain the overall strength of the third part 3233, reduce the risk of deformation or collapse, and improve the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0151] In some embodiments, the cover body 31 is provided with a pressure relief mechanism 60. The pressure relief mechanism 60 may be part of the cover body 31 or may be a separate structure from the cover body 31. Optionally, the cover body 31 is provided with a pressure relief hole 3111, and the pressure relief mechanism 60 is fixed to the cover body 31 by welding or other means and covers the pressure relief hole 3111.

[0152] The gas within the first gap 51 can act on the pressure relief mechanism 60. The pressure relief mechanism 60 can be actuated to release internal pressure when the internal pressure or temperature of the battery cell 6 reaches a threshold. Optionally, the pressure relief mechanism 60 may be provided with a weak structure. When the pressure relief mechanism 60 is actuated, its weak structure ruptures, and gas and other high-temperature and high-pressure substances are released outward through the opening and pressure relief hole 3111 formed by the rupture of the pressure relief mechanism 60, reducing the possibility of the battery cell 6 exploding.

[0153] For example, the pressure relief mechanism 60 may be an explosion-proof valve, a gas valve, a pressure relief valve, or other suitable form.

[0154] In some embodiments, the first protrusion 32 includes two fourth wall portions 324, which are disposed opposite each other along the second direction Y. The fourth wall portions 324 are connected to the first wall portion 321, the second wall portion 322 and the third wall portion 323. The first wall portion 321, the second wall portion 322, the third wall portion 323 and the fourth wall portion 324 surround to form a second recess 34, which forms at least a portion of the channel 52.

[0155] The first through hole 3234 is directly connected to the second recess 34, and the second recess 34 can be directly or indirectly connected to the first gap 51.

[0156] The channel 52 includes at least the second recess 34, and the channel 52 may also include other connecting structures such as through holes, grooves, and gaps.

[0157] The fourth wall portion 324, together with the first wall portion 321, the second wall portion 322 and the third wall portion 323, forms an annular closed structure, which can improve the overall strength of the first protrusion 32, reduce the risk of deformation and collapse of the first protrusion 32, and help improve the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0158] The second recess 34 can reduce the weight of the first protrusion 32, improve the elasticity of the first protrusion 32, and reduce the risk of the first protrusion 32 damaging the electrode assembly 10 when the battery cell 6 vibrates. In addition, the second recess 34 can also form at least part of the channel 52, which can provide a larger buffer space for gas and help relieve gas pressure.

[0159] In some embodiments, refer to Figure 7The second wall portion 322 is provided with a second through hole 3221, which penetrates the second wall portion 322 along the first direction X. The channel 52 includes a second recess 34 and a second through hole 3221.

[0160] The second through hole 3221 directly connects the second recess 34 and the first gap 51. The gas in the electrode assembly 10 can flow to the first gap 51 through the first through hole 3234, the second recess 34 and the second through hole 3221 in sequence, which helps to shorten the gas flow path and reduce the gas flow resistance.

[0161] In some embodiments, the outer diameter of the second through hole 3221 is 0.4mm-1.8mm.

[0162] The shape of the second through hole 3221 can be circular, square, triangular or other suitable shapes.

[0163] When the second through hole 3221 is a circular hole, its outer diameter is its diameter. When the second through hole 3221 is a non-circular hole, its outer diameter refers to the diameter of its circumcircle.

[0164] Optionally, the outer diameter of the second through hole 3221 can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, or any value between any two of these.

[0165] If the outer diameter of the second through hole 3221 is too small, it will create greater resistance to the gas and prevent the gas from flowing effectively; if the outer diameter of the second through hole 3221 is too large, it will affect the overall strength of the second wall portion 322, and thus affect the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0166] In this embodiment, the outer diameter of the second through hole 3221 is set to 0.4mm-1.8mm, which is beneficial for the smooth discharge of gas inside the electrode assembly 10 through the second through hole 3221, and also helps to maintain the overall strength of the second wall portion 322, reduce the risk of deformation or collapse, and improve the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0167] In some embodiments, refer to Figure 6 and Figure 9 The fourth wall portion 324 is provided with a third through hole 3241, which penetrates the fourth wall portion 324 along the second direction Y. The channel 52 includes a second recess 34 and a third through hole 3241.

[0168] The third through hole 3241 can directly connect to the second recess 34 and the gap between the first protrusion 32 and the side wall of the housing 20. The gap between the first protrusion 32 and the side wall of the housing 20 is connected to the first gap 51, and the third through hole 3241 is indirectly connected to the first gap 51. Gas in the electrode assembly 10 can flow sequentially through the first through hole 3234, the second recess 34, the third through hole 3241, and the gap between the first protrusion 32 and the side wall of the housing 20 to the first gap 51. The channel 52 may include the gap between the first protrusion 32 and the side wall of the housing 20.

[0169] In some embodiments, the outer diameter of the third through hole 3241 is 0.4mm-1.8mm.

[0170] The shape of the third through hole 3241 can be circular, square, triangular or other suitable shapes.

[0171] When the third through hole 3241 is a circular hole, its outer diameter is its diameter. When the third through hole 3241 is a non-circular hole, its outer diameter refers to the diameter of its circumcircle.

[0172] Optionally, the outer diameter of the third through hole 3241 can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, or any value between any two of these.

[0173] If the outer diameter of the third through hole 3241 is too small, it will create greater resistance to the gas and prevent the gas from flowing effectively; if the outer diameter of the third through hole 3241 is too large, it will affect the overall strength of the fourth wall portion 324, and thus affect the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0174] In this embodiment, the outer diameter of the third through hole 3241 is set to 0.4mm-1.8mm, which is beneficial for the smooth discharge of gas inside the electrode assembly 10 through the third through hole 3241, and also helps to maintain the overall strength of the fourth wall portion 324, reduce the risk of deformation or collapse, and improve the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0175] In some embodiments, the size of the first recess 33 along the first direction X is w, where 1mm ≤ w ≤ 3mm.

[0176] Optionally, the dimension w of the first recess 33 along the first direction X can be 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, or any value between any two of them.

[0177] If the size of the first recess 33 is too small, the clearance space it can provide is small and cannot effectively alleviate the pressure damage to the outer electrode plate and the separator; if the size of the first recess 33 is too large, it will reduce the area of ​​the first protrusion 32 that abuts against the electrode assembly 10, affecting the overall strength of the first protrusion 32, thereby affecting the limiting effect on the electrode assembly 10.

[0178] In this embodiment, the size w of the first recess 33 along the first direction X is set to 1mm-3mm, which can achieve a balance between reducing the risk of crushing of the outer ring electrode and the separator by the first protrusion 32 and improving the limiting effect of the first protrusion 32 on the electrode assembly 10.

[0179] In some embodiments, along the thickness direction Z of the cover body 31, the size of the first recess 33 is h, where 3.5mm ≤ h ≤ 6mm.

[0180] The dimension h of the first recess 33 along the thickness direction Z of the cover body 31 can be the depth of the first recess 33.

[0181] Optionally, the dimension h of the first recess 33 along the thickness direction Z can be 3.5mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, 6.0mm or any value between any two of them.

[0182] If the depth of the first recess 33 is too large, it will affect the overall strength of the first protrusion 32; if the depth of the first recess 33 is too small, the protruding outer ring electrode and the insulating member of the electrode assembly 10 will still press against the bottom wall of the first recess 33, which also poses a risk of damaging the outer ring electrode and the insulating member.

[0183] In this embodiment, the dimension h of the first recess 33 along the thickness direction Z is set to 3.5mm-6mm, which can achieve a balance between the overall strength of the first protrusion 32 and reducing the risk of damaging the outer electrode and the separator.

[0184] In some embodiments, there are two first protrusions 32, which are located at opposite ends of the cover body 31 along the first direction X. The cover assembly 30 also includes a second protrusion 35, which protrudes from the first surface 312a toward the electrode assembly 10, and is located between the two first protrusions 32 and abuts against the electrode assembly 10.

[0185] The first gap 51 may include two portions located on either side of the second protrusion 35 along the first direction X.

[0186] The second protrusion 35 may be provided with a connecting structure to connect the two parts of the first gap 51. Optionally, the second protrusion 35 may be provided with a recess or through hole that extends through the second protrusion 35 along the first direction X, and the two parts of the first gap 51 are connected through the recess or through hole.

[0187] The two first protrusions 32 can make the electrode assembly 10 more evenly stressed, reduce stress concentration, and improve the stability of the electrode assembly 10. The second protrusion 35 can also increase the overall strength of the cover assembly 30, reduce the risk of deformation and collapse of the cover assembly 30, and improve structural stability.

[0188] In some embodiments, the cover body 31 includes a first cover portion 311 and a second cover portion 312. The first cover portion 311 covers the opening 21, and the second cover portion 312 is disposed on the side of the first cover portion 311 facing the electrode assembly 10. A first surface 312a is the surface of the second cover portion 312 facing the electrode assembly 10, and a first protrusion 32 is disposed at the end of the second cover portion 312 along the first direction X.

[0189] The material of the first cover body 311 may include metallic materials, such as aluminum or aluminum alloys, which can enhance the overall structural strength of the cover body 31.

[0190] The second cover portion 312 can be made of plastic to reduce the weight of the cover body 31 while insulating and isolating the first cover portion 311 and the electrode assembly 10.

[0191] The first cover portion 311 and the second cover portion 312 can be connected by adhesive, snap-fit ​​or other suitable means.

[0192] In some embodiments, the first protrusion 32 and the second cover portion 312 may be integrally formed. Optionally, the first protrusion 32, the second protrusion 35, and the second cover portion 312 may all be integrally formed. The end cap may be the first cover portion 311, and the insulating member may include the second cover portion 312, the first protrusion 32, and the second protrusion 35.

[0193] The cover body 31 of this application embodiment includes a first cover part 311 and a second cover part 312, which not only helps to improve the overall structural strength of the cover body 31, but also achieves insulation isolation between the cover body 31 and the electrode assembly 10.

[0194] According to some embodiments of this application, this application also provides a battery device 2, which includes a plurality of battery cells 6 provided in any of the above embodiments.

[0195] According to some embodiments of this application, this application also provides an electrical device, which includes a battery device 2 of any of the above embodiments, the battery device 2 being used to provide electrical energy.

[0196] The battery cell 6 provided in this embodiment includes a housing 20, an electrode assembly 10, and a cover assembly 30. The housing 20 has an opening 21. The electrode assembly 10 is housed within the housing 20. The cover assembly 30 includes a first cover portion 311, a second cover portion 312, and a first protrusion 32. The first cover portion 311 connects to the housing 20 and covers the opening 21. The second cover portion 312 has a first surface 312a facing the electrode assembly 10. The first protrusion 32 is provided at the end of the second cover portion 312 along a first direction X, and the first protrusion 32 protrudes from the first surface 312a in a direction close to the electrode assembly 10. A first recess 33 is formed on the side of the first protrusion 32 facing the electrode assembly 10. The first protrusion 32 includes a first wall portion 321 and a second wall portion 322 disposed opposite to each other along the first direction X, a third wall portion 323 connecting the first wall portion 321 and the second wall portion 322, and two fourth wall portions 324. The first wall portion 321 is located outside the second wall portion 322, and the second wall portion 322 abuts against the electrode assembly 10. The third wall portion 323 includes a first part 3231, a second part 3232, and a third part 3233. The first part 3231 is connected to the first wall portion 321, and the third part 3233 is connected to the second wall portion 322. The third part 3233 is located on the side of the first part 3231 closest to the electrode assembly 10 and can abut against the electrode assembly 10. The second part 3232 is connected between the first part 3231 and the third part 3233. The first wall portion 321 and the third wall portion 323 together form a first recess 33. The third part 3233 is provided with a first through hole 3234, which penetrates the third part 3233 along the thickness direction Z of the cover body 31. The outer diameter of the first through hole 3234 is 0.4mm-1.8mm. The fourth wall portion 324 connects to the first wall portion 321, the second wall portion 322, and the third wall portion 323. The first wall portion 321, the second wall portion 322, the third wall portion 323, and the fourth wall portion 324 together form a second recess 34. The fourth wall portion 324 is provided with a third through hole 3241, which penetrates the fourth wall portion 324 along the second direction Y. Along the first direction X of the cover body 31, the dimension of the first recess 33 is w, where 1mm ≤ w ≤ 3mm. Along the thickness direction Z of the cover body 31, the dimension of the first recess 33 is h, where 3.5mm ≤ h ≤ 6mm.

[0197] 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 by, Including: a case having an opening; an electrode assembly accommodated in the case; and a cap assembly including a cap body connected to the case and covering the opening, the cap body having a first surface facing the electrode assembly, and a first protrusion provided at an end of the cap body in a first direction and protruding from the first surface toward the electrode assembly; the first protrusion including first and second wall portions disposed opposite each other in the first direction, and a first recess formed in a side of the first protrusion facing the electrode assembly. 2.The battery cell of claim 1, wherein: the first wall portion is provided outside the second wall portion in the first direction, the first wall portion forms a part of a wall portion enclosing the first recess, and the second wall portion abuts against the electrode assembly. 3.The battery cell of claim 2, wherein: a part of the second wall portion protrudes beyond the first wall portion in a direction toward the electrode assembly in a thickness direction of the cap body, the thickness direction being perpendicular to the first direction. 4.The battery cell of claim 2 or 3, wherein: the first wall portion has a second surface facing the first recess, and an extension of the second surface in the thickness direction of the cap body in the first direction is located between the electrode assembly and the case. 5.The battery cell of claim 2 or 3, wherein: the first wall portion includes a main portion and a thinned portion connected to the main portion, the thinned portion being located at a side of the main portion closer to the electrode assembly; a thickness of the thinned portion is smaller than a thickness of the main portion in the first direction, and the thickness of the thinned portion is smaller than a thickness of the second wall portion; the thinned portion forms a part of a wall portion enclosing the first recess. 6.The battery cell of claim 5, wherein: the thickness of the thinned portion is d1, and 0.5 mm ≤ d1 ≤ 1 mm in the first direction. 7.The battery cell of claim 2 or 3, wherein: the first recess penetrates through the first protrusion in a second direction, the second direction being perpendicular to the first direction. 8.The battery cell of claim 7, wherein: the first protrusion includes a third wall portion connected between the first and second wall portions, the first, second, and third wall portions enclosing the first recess; a thickness of the first wall portion is smaller than a thickness of the second wall portion in the first direction. 9.The battery cell of claim 7, wherein: the first protrusion includes a third wall portion connected between the first and second wall portions. ​ The third wall portion includes a first portion, a second portion, and a third portion, the first portion is connected to the first wall portion, the third portion is connected to the second wall portion, the third portion is located on a side of the first portion close to the electrode assembly and can abut against the electrode assembly, and the second portion is connected between the first portion and the third portion. The first wall portion and the third wall portion enclose the first recess.

10. The battery cell according to claim 9, wherein The first protrusions are two, and the two first protrusions are respectively located at two ends of the cover body along the first direction. A first gap is formed between the cover body and the electrode assembly, and along the first direction, the first gap is located between the two first protrusions. The third portion is provided with a first through hole, and the first through hole penetrates through the third portion along the thickness direction of the cover body. The first protrusion is provided with a channel, and the channel communicates the first gap and the first through hole.

11. The battery cell according to claim 10, wherein The first protrusion includes two fourth wall portions, and the two fourth wall portions are oppositely arranged along the second direction, the fourth wall portion is connected to the first wall portion, the second wall portion, and the third wall portion, the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion enclose a second recess, and the second recess forms at least part of the channel.

12. The battery cell according to claim 11, wherein The second wall portion is provided with a second through hole, the second through hole penetrates through the second wall portion along the first direction, and the channel includes the second recess and the second through hole; and / or The fourth wall portion is provided with a third through hole, the third through hole penetrates through the fourth wall portion along the second direction, and the channel includes the second recess and the third through hole.

13. The battery cell according to claim 12, wherein An outer diameter of the second through hole is 0.4 mm-1.8 mm; and / or An outer diameter of the third through hole is 0.4 mm-1.8 mm.

14. The battery cell according to any one of claims 10-13, wherein An outer diameter of the first through hole is 0.4 mm-1.8 mm.

15. The battery cell according to any one of claims 1-3, 8-13, wherein Along the first direction, a size of the first recess is w, and 1 mm≤w≤3 mm; and / or Along the thickness direction of the cover body, a size of the first recess is h, and 3.5 mm≤h≤6 mm, and the thickness direction is perpendicular to the first direction.

16. The battery cell according to any one of claims 1-3, 8-13, wherein The first protrusions are two, and the two first protrusions are respectively located at two ends of the cover body along the first direction. The cover assembly further includes a second protrusion, the second protrusion protrudes from the first surface in a direction close to the electrode assembly, and the second protrusion is located between the two first protrusions and abuts against the electrode assembly.

17. The battery cell according to any one of claims 1 to 3, 8 to 13, wherein the cover body includes a first cover portion that covers the opening and a second cover portion that is provided on a side of the first cover portion facing the electrode assembly, the first surface is a surface of the second cover portion facing the electrode assembly, and the first protrusion is provided at an end portion of the second cover portion in the first direction.

18. A battery device, characterized by a plurality of battery cells according to any one of claims 1 to 17.

19. An electrical device, characterized by a battery device according to claim 18, the battery device being used to supply electric power.

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