Battery cell, battery device, and electric device

Abstract

Embodiments of the present application disclose a battery monomer, a battery device and an electric equipment, and relate to the field of batteries. The battery monomer comprises a shell, an electrode assembly, a lower plastic and an end cover. The shell comprises an opening. The electrode assembly is accommodated in the shell. The lower plastic covers the opening and comprises a protrusion located on a side of the lower plastic away from the electrode assembly. The end cover is connected with the lower plastic to cover the opening. The end cover comprises a blind hole located on a side of the end cover close to the protrusion, and the blind hole is connected with the protrusion. The blind hole comprises a first blind hole part and a second blind hole part. The first blind hole part is located on a side of the second blind hole part away from the electrode assembly. The maximum area of the projection of the first blind hole part towards the end cover is greater than the maximum area of the projection of the second blind hole part towards the end cover. The projections of the first blind hole part and the second blind hole part towards the end cover are rectangular. The contact area between the lower plastic and the end cover can be increased, the pulling force of the end cover on the lower plastic can be improved, and the stability of the battery monomer can be improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical appliance. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the automotive industry's sustainable development. And for electric vehicles, battery technology is a crucial factor in their development.

[0003] For individual battery cells, the stability of their internal structure affects battery performance. When subjected to external forces such as vibration and impact, individual battery cells are prone to loosening or separation of components. Therefore, how to improve the stability of the internal structure of individual battery cells is a technical problem that urgently needs to be solved. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical appliance, which can increase the contact area between the lower plastic and the end cap, and increase the pulling force of the end cap on the lower plastic, thereby improving the stability of the battery cell.

[0005] In a first aspect, this application provides a battery cell, comprising: a housing, an electrode assembly, a lower plastic, and an end cap. The housing includes an opening; the electrode assembly is housed within the housing; the lower plastic covers the opening and includes a protrusion located on the side of the lower plastic away from the electrode assembly; the end cap is connected to the lower plastic to close the opening, and the end cap includes a blind hole located on the side of the end cap near the protrusion, the blind hole engaging with the protrusion; wherein the blind hole includes a first blind hole portion and a second blind hole portion, the first blind hole portion being located on the side of the second blind hole portion away from the electrode assembly, the maximum area of ​​the first blind hole portion projected toward the end cap is greater than the maximum area of ​​the second blind hole portion projected toward the end cap, and the projections of the first blind hole portion and the second blind hole portion toward the end cap are rectangular.

[0006] In this embodiment, the blind hole enhances the pulling force on the lower plastic by using a larger first blind hole portion and a smaller second blind hole portion. When the battery is subjected to external forces such as vibration or impact, the difference in cross-sectional area between the first and second blind hole portions allows the blind hole to hold the protrusion in place, increasing the friction and constraint between them, preventing the protrusion from coming out of the blind hole, reducing the possibility of the lower plastic being pulled off, and improving the stability of the battery cell. Furthermore, when the blind hole projection is circular, the contact with the lower plastic is usually point or line contact, and the contact area is relatively small, which is not conducive to the stability between the protrusion and the blind hole. In this embodiment, the projections of the first and second blind hole portions toward the end cap are rectangular, which can fully utilize the area of ​​the entire rectangle to contact the lower plastic, increasing the contact area between the protrusion and the lower plastic, thereby improving the stability between the protrusion and the blind hole.

[0007] In some embodiments of the first aspect, the blind hole further includes a third blind hole portion located on the side of the second blind hole portion closer to the electrode assembly, wherein the minimum area of ​​the third blind hole portion projected toward the end cap is greater than the maximum area of ​​the second blind hole portion projected toward the end cap.

[0008] In this embodiment, a third blind hole is provided on the side of the second blind hole portion near the electrode assembly, and the minimum area of ​​the third blind hole portion projected toward the end cap is greater than the maximum area of ​​the second blind hole portion projected toward the end cap. That is, the area of ​​the third blind hole portion that first contacts the protrusion is designed to maximize the area that can be heated and reduce the power during heating and melting. During assembly, the third blind hole portion provides a large initial entry space for the protrusion, which facilitates the protrusion entering the blind hole.

[0009] In some embodiments of the first aspect, the projection of the third blind hole toward the end cap is rectangular.

[0010] In the embodiments of this application, when the projection of the third blind hole toward the end cap is rectangular during the initial contact between the protrusion and the blind hole, the contact between the two is a surface contact. Therefore, compared with circular point contact or line contact, the technical solution of this application can increase the contact area between the two, thereby improving the stability between the protrusion and the blind hole.

[0011] In some embodiments of the first aspect, the minimum area of ​​the third blind hole portion projected toward the end cap is greater than the maximum area of ​​the first blind hole portion projected toward the end cap.

[0012] In this embodiment, since the minimum area of ​​the third blind hole portion projected toward the end cap is greater than the maximum area of ​​the first blind hole portion projected toward the end cap, the third blind hole portion provides a large initial entry space for the protrusion during assembly, making it easier for the protrusion to enter the blind hole.

[0013] In some embodiments of the first aspect, the ratio L1 of the length to the width of the rectangle projected by the third blind hole toward the end cap is in the range of 2≤L1≤4.

[0014] In this embodiment, if the ratio of the rectangle's length to its width is too large, i.e., the rectangle's area is too large, the protrusions may be difficult to control during the hot-melt process, making it difficult to accurately fill the blind holes and potentially overflowing into unwanted areas. Furthermore, uneven distribution of the protrusions within the blind holes will result in uneven density of the entire solidified component, affecting the stability of the battery cell. If the ratio of the rectangle's length to its width is too small, i.e., the rectangle's area is too small, the protrusions may have difficulty flowing into the blind holes during the hot-melt process. Additionally, a ratio that is too small may cause air to remain within the blind holes, forming bubbles and affecting the stability between the protrusions and the blind holes.

[0015] In some embodiments of the first aspect, the maximum area of ​​the protrusion projected toward the end cap is less than or equal to the minimum area of ​​the second blind hole portion projected toward the end cap.

[0016] In this embodiment, when the maximum area of ​​the protrusion projected toward the end cap is less than or equal to the minimum area of ​​the second blind hole projected toward the end cap, the protrusion can be easily and accurately aligned with and inserted into the second blind hole during the assembly process of the end cap and the lower plastic. This reduces the possibility that the end cap and the lower plastic cannot be connected due to mismatch between the protrusion and the blind hole, and shortens the assembly time of the end cap and the lower plastic, thereby improving assembly efficiency.

[0017] In some embodiments of the first aspect, the first blind hole portion includes a first end face and a second end face, the first end face being located on the side of the second end face away from the electrode assembly, and the cross-sectional area of ​​the first blind hole portion gradually decreases along the thickness direction of the end cap from the first end face to the second end face.

[0018] In this embodiment, the gradually decreasing cross-sectional area of ​​the first blind hole provides a guiding structure for the protrusion of the lower plastic, facilitating its entry into the first blind hole. When the protrusion is a hot-melt column, the hot-melt column melts upon heating, and the gradually decreasing cross-sectional area provides a backflow slope for the molten hot-melt column. As the hot-melt column gradually melts, the liquid hot-melt material flows along the second end face to the first end face, filling the blind hole. This results in a tight and seamless connection between the hot-melt column and the blind hole after solidification, enhancing the stability of the connection. In this way, the battery cell can have a stable connection structure after assembly, improving the integrity and stability of the battery's internal structure.

[0019] In some embodiments of the first aspect, the dimension L2 of the blind hole along the thickness direction of the end cap ranges from 0.5 mm to L2 to 1.5 mm.

[0020] In this embodiment, the dimension of the blind hole along the thickness direction of the end cap is within 0.5mm to 1.5mm, which can improve the strength of the end cap itself. If it is too large, the strength of the entire end cap may be insufficient, which is not conducive to the integrity and stability of the battery cell. In addition, the dimension of the blind hole along the thickness direction of the end cap is within 0.5mm to 1.5mm, which can make the protrusion and the blind hole have a stable connection structure, thus improving the integrity and stability of the internal structure of the battery cell.

[0021] In some embodiments of the first aspect, the end cap includes at least two blind holes, which are evenly distributed near the edge of the end cap.

[0022] In this embodiment, when a battery cell is subjected to external impact, vibration, or pressure, the uniformly distributed blind holes near the edge can evenly disperse stress at the edge of the end cap, effectively preventing stress concentration and improving the end cap's resistance to deformation and the overall structural stability. During assembly, the uniformly distributed blind holes provide positioning references, facilitating the assembly of various structures within the battery cell.

[0023] In some embodiments of the first aspect, the volume of the blind hole is greater than or equal to the volume of the protrusion.

[0024] In this embodiment, the volume of the blind hole is greater than or equal to the volume of the protrusion, allowing the blind hole to accommodate the protrusion and thus enabling a tight connection between the end cap and the lower plastic. A suitable blind hole volume provides more stable support for the protrusion. Furthermore, a suitable volume relationship between the blind hole and the protrusion helps improve the sealing performance of the battery cell. After the protrusion is inserted into the blind hole, a tighter sealing structure can be formed between the two through appropriate manufacturing processes.

[0025] In some embodiments of the first aspect, the protrusion includes a pyramidal head and a prismal body, the maximum area of ​​the pyramidal head projected toward the end cap being equal to the area of ​​the prismal body projected toward the end cap.

[0026] In this embodiment, the pyramidal head design provides guidance for the protrusion during assembly. When assembling the plastic and the end cap, the pyramidal head can easily align with the entrance of the blind hole in the end cap, and even if there is a certain positional deviation, the position can be smoothly corrected during insertion. In addition, the protrusion has a prismatic structure, that is, its projection towards the end cap is rectangular, which can better fit with the blind hole and increase the contact area between the two, thereby improving the stability of the battery cell. Furthermore, the design that the maximum area of ​​the pyramidal head projection is equal to the projection area of ​​the prism-shaped main body ensures a smooth transition when inserting into the blind hole, without any jamming or assembly difficulties caused by abrupt changes in size.

[0027] In some embodiments of the first aspect, the angle between the side edges of the pyramidal head and the bottom surface near the prismal body is... The scope is:

[0028] In this embodiment, the angle between the side edge of the pyramidal head and the bottom surface near the prismal body is within 30° to 60°, which better facilitates the connection between the protrusion and the blind hole, thereby improving the stability of the battery cell. An excessively large angle may reduce the contact area between the pyramidal head and the opening of the blind hole, making it difficult for the protrusion to smoothly enter the blind hole. Conversely, an excessively small angle will slow down the speed at which the protrusion enters the blind hole, reducing production efficiency.

[0029] In some embodiments of the first aspect, the maximum area of ​​the prism-shaped main body portion projected toward the end cap is less than or equal to the minimum area of ​​the second blind hole portion projected toward the end cap.

[0030] In this embodiment, the pyramidal head design provides guidance for the protrusion during assembly. When assembling the lower plastic part and the end cap, the pyramidal head can easily align with the entrance of the blind hole in the end cap, and even if there is a certain positional deviation, the position can be smoothly corrected during insertion. The design that the maximum projected area of ​​the pyramidal head is equal to the projected area of ​​the columnar main body ensures a smooth transition when inserting into the blind hole, without any jamming or assembly difficulties caused by abrupt changes in size.

[0031] In a second aspect, this application provides a battery device, comprising: a plurality of battery cells; the plurality of battery cells including the battery cells in the first aspect; and a battery housing, in which the plurality of battery cells are housed.

[0032] Thirdly, this application provides an electrical device, including a battery device comprising the battery device of the second aspect, the battery device being used to provide electrical energy.

[0033] In some embodiments, the electrical device is a vehicle, a ship, or a spacecraft. Attached Figure Description

[0034] Figure 1 This is a structural diagram of a vehicle provided in an embodiment of this application.

[0035] Figure 2 This is a structural diagram of a battery device provided in an embodiment of this application.

[0036] Figure 3 This is a structural diagram of a battery cell provided in an embodiment of this application.

[0037] Figure 4 An exploded view of a single battery cell provided in an embodiment of this application.

[0038] Figure 5 This is a structural diagram of an end cap provided in an embodiment of this application.

[0039] Figure 6 This is a cross-sectional view of an end cap provided in an embodiment of this application.

[0040] Figure 7 This is a partial cross-sectional view of an end cap provided in an embodiment of this application.

[0041] Figure 8 This is a projection view of an end cap provided in an embodiment of this application.

[0042] Figure 9 This is a cross-sectional view of another end cap provided in an embodiment of this application.

[0043] Figure 10 A cross-sectional view of another end cap provided in an embodiment of this application.

[0044] Figure 11 A cross-sectional view of another end cap provided in an embodiment of this application.

[0045] Figure 12 This is a partial cross-sectional view of another end cap provided in an embodiment of this application.

[0046] Figure 13 This is a projection view of another end cap provided in an embodiment of this application.

[0047] Figure 14 A cross-sectional view of another end cap provided in an embodiment of this application.

[0048] Figure 15 This is a structural diagram of a lower plastic material provided in an embodiment of this application.

[0049] Figure 16 This is a partial structural diagram of a lower plastic material provided in an embodiment of this application.

[0050] Figure 17 This is a structural diagram of a protrusion provided in an embodiment of this application.

[0051] Figure 18 This is another structural diagram of a protrusion provided in an embodiment of this application.

[0052] The accompanying drawings are not drawn to scale.

[0053] Figure label:

[0054] 1000 - Vehicle; 100 - Battery assembly; 10 - Battery housing; 101 - First housing section; 102 - Second housing section; 20 - Battery cell; 21 - Housing; 211 - Opening; 22 - End cap; 221 - Blind hole; 2211 - First blind hole section; 2212 - Second blind hole section; 2213 - Third blind hole section; 2215 - First end face; 2216 - Second end face; 23 - Electrode terminal; 24 - Pressure relief mechanism; 25 - Electrode assembly; 251 - Tab; 26 - Lower plastic; 261 - Protrusion; 2611 - Pyramidal head; 2612 - Prismatic main body section; 200 - Motor; 300 - Controller. Detailed Implementation

[0055] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0056] 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.

[0057] 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.

[0058] In this application, the reference to "embodiment" means that a specific 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

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

[0064] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0065] 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.

[0066] 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.

[0067] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the negative and positive electrodes. 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, reduces the occurrence of short circuits while allowing active ions to pass through.

[0068] 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.

[0069] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0070] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0071] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0072] 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.

[0073] 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.

[0074] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0075] Liquid electrolytes include electrolyte salts and solvents.

[0076] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid—lithium salt.

[0077] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0078] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0079] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0080] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0081] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0082] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0083] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0084] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0085] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby creating an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0086] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0087] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0088] The battery apparatus 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 connected in series, parallel, or mixed connections via a busbar.

[0089] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0090] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0091] In some embodiments, the battery device may be a battery pack, which includes a battery housing and one or more individual battery cells housed within the battery housing.

[0092] As an example, a battery cell assembly can be a battery module, which can be housed in a battery housing by fixing the battery module in the battery housing.

[0093] As an example, battery cell assemblies can also be housed in a battery housing by directly fixing multiple battery cells to the battery housing.

[0094] As an example, the battery housing may include a first battery housing and a second battery housing portion. The first battery housing portion and the second battery housing portion are fastened together to form a closed space inside the battery housing for housing individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first battery housing may be a top cover or a bottom plate.

[0095] As an example, the battery enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, so that the interior of the battery enclosure forms an enclosed space to house individual battery cells.

[0096] In some embodiments, the battery housing may be part of the vehicle's chassis structure. For example, a portion of the battery housing may be at least a part of the vehicle's floor, or a portion of the battery housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0097] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0098] Currently, the reliability of the connection between the top cover and the lower plastic of a battery cell is crucial for improving the cell's insulation and structural strength. Typically, the top cover and lower plastic are connected via a hot-melt column that melts the lower plastic, integrating the melt into the undercut hole of the top cover. However, if the interface morphology of the circular undercut hole and the lower plastic during the hot-melt process is poor, it cannot effectively strengthen the overall structure. Furthermore, increasing the size of the undercut hole requires a larger hot-melt column, necessitating increased hot-melt power and causing shrinkage of the lower plastic. This further leads to physical swelling of the lower plastic after electrolyte wetting, causing it to detach, occupying space in the electrode tabs, and resulting in damage to the electrode tabs or electrode sheets.

[0099] Based on the above considerations, this application provides a battery cell that increases the contact area between the lower plastic and the end cap, thereby increasing the pull force of the end cap on the lower plastic and improving the stability of the battery cell. The battery cell provided in this application includes a housing, an electrode assembly, a lower plastic, and an end cap. The housing includes an opening. The electrode assembly is housed within the housing. The lower plastic covers the opening and includes a protrusion located on the side of the lower plastic away from the electrode assembly. The end cap is connected to the lower plastic to close the opening. The end cap includes a blind hole located on the side of the end cap near the protrusion, and the blind hole engages with the protrusion. The blind hole includes a first blind hole portion and a second blind hole portion. The first blind hole portion is located on the side of the second blind hole portion away from the electrode assembly. The maximum area of ​​the first blind hole portion projected onto the end cap is greater than the maximum area of ​​the second blind hole portion projected onto the end cap, and the projections of the first and second blind hole portions onto the end cap are rectangular.

[0100] In such a battery cell, the blind hole enhances the tension on the lower plastic by using a larger first blind hole portion and a smaller second blind hole portion. When the battery is subjected to external forces such as vibration or impact, the difference in cross-sectional area between the first and second blind hole portions allows the blind hole to hold the protrusion in place, increasing the friction and constraint between them, preventing the protrusion from coming out of the blind hole, reducing the possibility of the lower plastic being pulled off, and improving the stability of the battery cell. Furthermore, when the blind hole projection is circular, the contact with the lower plastic is usually point or line contact, and the contact area is relatively small, which is not conducive to the stability between the protrusion and the blind hole. In this application, the projections of the first and second blind hole portions toward the end cap are rectangular, which can fully utilize the area of ​​the entire rectangle to contact the lower plastic, increasing the contact area between the protrusion and the lower plastic, thereby improving the stability between the protrusion and the blind hole.

[0101] The technical solutions described in this application are applicable to various electrical devices that use battery devices. These electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0102] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0103] For example, Figure 1 This is a structural diagram of a vehicle provided as an embodiment of this application. Figure 1As shown, 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, a motor 200, and a controller 300 can be installed inside vehicle 1000. The controller 300 controls the power supply from the battery device 100 to the motor 200. For example, the battery device 100 can be installed at the bottom, front, or rear of vehicle 1000. The battery device 100 can be used to power vehicle 1000; for example, it can serve as the operating power source for vehicle 1000's electrical system, such as for the power requirements of starting, navigation, and operation. In another embodiment of this application, the battery device 100 can not only serve as the operating power source for vehicle 1000 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving force for vehicle 1000.

[0104] Figure 2 This is a structural diagram of a battery device provided in an embodiment of this application. Figure 2 As shown, the battery device 100 of this application embodiment may include a plurality of battery cells 20 to meet different power usage needs.

[0105] It should be understood that, such as Figure 2 As shown, the battery device 100 in this embodiment may further include a battery housing 10.

[0106] The battery housing 10 may include two parts, referred to herein as a first housing part 101 and a second housing part 102, which are fastened together. The shapes of the first housing part 101 and the second housing part 102 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of multiple battery cells 20 housed inside. At least one of the first housing part 101 and the second housing part 102 has an opening. For example, the first housing part 101 and the second housing part 102 may both be hollow cuboids with one face as an opening. The opening 211 of the first housing part 101 and the opening of the second housing part 102 are arranged opposite to each other, and the first housing part 101 and the second housing part 102 are fastened together to form a battery housing 10 with a closed cavity, which can be used to house multiple battery cells 20. Multiple battery cells 20 are connected in parallel, series, or mixed and placed inside the battery housing 10 formed by the fastening of the first housing part 101 and the second housing part 102.

[0107] For example, one of the first housing portion 101 and the second housing portion 102 may be a hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 102 as a hollow cuboid with one opening, and the first housing portion 101 as a plate-shaped example, then the first housing portion 101 covers the opening 211 of the second housing portion 102 to form a battery housing 10 with a closed chamber, which can be used to accommodate multiple battery cells 20.

[0108] Figure 3 This is a structural diagram of a battery cell provided in an embodiment of this application. Figure 4 An exploded view of a single battery cell provided in an embodiment of this application. Figure 5 This is a structural diagram of an end cap provided in an embodiment of this application. Figure 6 This is a cross-sectional view of an end cap provided in an embodiment of this application. Figure 7 This is a partial cross-sectional view of an end cap provided in an embodiment of this application. Figure 8 This is a projection view of an end cap provided in an embodiment of this application. Figures 3 to 8 As shown, the battery cell 20 in this embodiment includes a housing 21, an electrode assembly 25, a lower plastic 26, and an end cap 22. The housing 21 includes an opening 211; the electrode assembly 25 is housed in the housing 21; the lower plastic 26 covers the opening 211 and includes a protrusion 261 located on the side of the lower plastic 26 away from the electrode assembly 25; the end cap 22 is connected to the lower plastic 26 to close the opening 211, and the end cap 22 includes a blind hole 221 located near the protrusion of the end cap 22. On one side of protrusion 261, blind hole 221 engages with protrusion 261; wherein, blind hole 221 includes a first blind hole portion 2211 and a second blind hole portion 2212, the first blind hole portion 2211 is located on the side of the second blind hole portion 2212 away from electrode assembly 25, the maximum area of ​​the first blind hole portion 2211 projected toward end cover 22 is greater than the maximum area of ​​the second blind hole portion 2212 projected toward end cover 22, and the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward end cover 22 are rectangular.

[0109] In some embodiments, the housing 21 is a hollow structure with an opening 211, and the electrode assembly 25 is housed within the housing 21. The shape of the housing 21 can be determined according to the specific shape of the electrode assembly 25. For example, if the electrode assembly 25 is a cuboid structure, the housing 21 can also be a cuboid structure. Figure 3 and Figure 4 An exemplary case is shown where the housing 21 and electrode assembly 25 are square.

[0110] The shell 21 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this application embodiment does not limit this.

[0111] End cap 22 is used to seal opening 211 to form a sealed mounting space for accommodating electrode assembly 25. The mounting space is also used to accommodate electrolyte, such as electrolyte solution.

[0112] The battery cell 20 may also include electrode terminals 23, a pressure relief mechanism 24, and an electrode assembly 25. The electrode terminals 23 are mounted on the end cap 22 and are used to connect with the electrode assembly 25, that is, the electrode terminals 23 are connected to the tabs 251 of the electrode assembly 25.

[0113] The end cap 22 is also equipped with a pressure relief mechanism 24. When the internal pressure of the battery cell 20 rises abnormally, the pressure relief mechanism 24 can be activated in time to release the excessive pressure inside the battery cell 20, thereby reducing the possibility of dangerous situations such as the battery cell 20 exploding.

[0114] In some embodiments, the shape of the battery cell 20 can be flexibly set according to the actual application, that is, the shell 21 of the battery cell 20 can be any polyhedral structure, for example, it can be set as a cuboid or a cylinder.

[0115] In some embodiments, the lower plastic layer 26 serves as an insulating layer between the internal and external environments of the battery cell 20, providing excellent insulation properties. During battery operation, the electrode assembly 25 generates an electric field, and the lower plastic layer 26 prevents current leakage to the outside, thus avoiding short circuits.

[0116] In this embodiment, the lower plastic 26 is flexible, and during the use of the battery device 100, it may be subjected to various external forces, such as vibration and impact. The flexibility of the lower plastic 26 allows it to absorb energy through its own deformation when subjected to these forces, thereby protecting the electrode assembly 25 inside the battery cell 20. The material of the lower plastic 26 may include rubber-like materials or thermoplastic elastomer-like materials.

[0117] In some embodiments, the end cap 22 is connected to the lower plastic 26 to cover the opening 211, i.e., the lower plastic 26 is located between the end cap 22 and the electrode assembly 25.

[0118] In this embodiment, the end cap 22 includes a blind hole 221, which is a non-permeable hole that does not penetrate the end cap 22. For example, in this embodiment, the depth of the blind hole 221 can be set between 0.5mm and 1.5mm to reduce the halo effect on the top cover. If the blind hole 221 is too shallow, the contact area between the end cap 22 and the lower plastic 26 will be too small, resulting in an unstable connection between the two. If the blind hole 221 is too deep, the top cover will have a halo effect, affecting the overall appearance. In addition, the depth of the blind hole 221 can also be determined according to the thickness of the top cover. For example, if the depth of the blind hole 221 exceeds 50% of the thickness of the top cover, it will cause a halo effect on the front of the top cover, affecting the appearance.

[0119] It should be understood that Figure 5 The side of the end cap 22 facing the electrode assembly 25. Figure 6 for Figure 5 Cross-sectional view at point 22A of the middle end cover. Figure 7 for Figure 6 A partial cross-sectional view of the end cap 22.

[0120] Specifically, the blind hole 221 is located on the side of the end cap 22 facing the electrode assembly 25, and engages with the protrusion 261 of the lower plastic 26, thereby achieving the connection between the end cap 22 and the lower plastic 26.

[0121] In this embodiment of the application, the blind hole 221 is composed of a first blind hole portion 2211 and a second blind hole portion 2212. The first blind hole portion 2211 is located on the side of the second blind hole portion 2212 away from the electrode assembly 25. That is, when the protrusion 261 is connected to the blind hole 221, it first enters the second blind hole portion 2212 and then enters the first blind hole portion 2211.

[0122] The blind hole 221 engages with the protrusion 261. For example, the shape of the protrusion 261 can be the same as that of the blind hole 221, and the two are tightly connected. That is, when the protrusion 261 is inserted into the blind hole 221, the gap between them is extremely small, and they can fit tightly together. Relative displacement will not easily occur, thus making the connection between the end cap 22 and the lower plastic 26 stable.

[0123] For example, the protrusion 261 can also be interference-fitted with the blind hole 221. That is, the size of the protrusion 261 is slightly larger than the size of the blind hole 221. During assembly, a certain amount of external force is required to press the protrusion 261 into the blind hole 221. During this process, the blind hole 221 will undergo a certain amount of elastic deformation. The pressure and friction generated by the interference fit are extremely large, which can enhance the connection strength between the protrusion 261 and the blind hole 221.

[0124] In this embodiment, the maximum area projected onto the end cap 22 by the first blind hole portion 2211 is greater than the maximum area projected onto the end cap 22 by the second blind hole portion 2212, meaning the cross-sectional area of ​​the first blind hole portion 2211 is greater than the cross-sectional area of ​​the second blind hole portion 2212. For example, the first blind hole portion 2211 can be a cylindrical hole with a larger diameter, while the second blind hole portion 2212 can be a cylindrical hole or a hole of other shapes with a smaller diameter, forming a stepped structure between them. As another example, the first blind hole portion 2211 can be a rectangular hole with a larger area, while the second blind hole portion 2212 can be a rectangular hole or a hole of other shapes with a smaller area, forming a stepped structure between them.

[0125] In some embodiments, the area of ​​the first blind hole portion 2211 projected toward the end cap 22 may not be a fixed value, and the area of ​​the second blind hole portion 2212 projected toward the end cap 22 may also not be a fixed value. That is, the first blind hole portion 2211 and the second blind hole portion 2212 may be frustum-shaped, prism-shaped, or polyhedral, as long as the maximum area of ​​the former is greater than the maximum area of ​​the latter.

[0126] For example, the minimum area of ​​the first blind hole portion 2211 projected toward the end cap 22 may be greater than the maximum area of ​​the second blind hole portion 2212 projected toward the end cap 22, and the minimum area of ​​the first blind hole portion 2211 projected toward the end cap 22 may be greater than the minimum area of ​​the second blind hole portion 2212 projected toward the end cap 22.

[0127] It should be understood that the first blind hole portion 2211 has a larger cross-sectional area. After the protrusion 261 is connected to the blind hole 221, as the contact area changes, the blind hole 221 can withstand greater tension, that is, the end cap 22 can withstand greater tension on the lower plastic 26.

[0128] For example, the protrusion 261 on the lower plastic 26 can be a hot melt column, which is a component that achieves a connection function by heating and melting.

[0129] Specifically, when connecting the hot melt column to the blind hole 221, heating equipment must first be prepared. Common heating equipment includes hot air guns, heating plates, and ultrasonic welding equipment. Align the hot melt column with the blind hole 221. Heat the hot melt column using the selected heating equipment. During the heating process, the heating temperature, time, and heating method must be strictly controlled. Excessive temperature may cause the hot melt column to over-melt, flowing to unwanted areas or even damaging the components; insufficient temperature may prevent the hot melt column from melting sufficiently, affecting the bonding effect. During the heating process, the melting state of the hot melt column should be closely observed. When the hot melt column begins to melt, its surface will become smooth and glossy, and gradually soften. After the hot melt column reaches the appropriate melting state, quickly press the lower plastic 26 and the end cap 22 together, so that the molten hot melt column fills the blind hole 221. Maintain constant pressure and allow the molten hot melt column to cool and solidify in the connected state.

[0130] Figure 8 This is a projection view of an end cap 22 provided in an embodiment of this application.

[0131] In some embodiments, such as Figure 8 As shown, the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cap 22 are rectangular. During the pressing process between the lower plastic 26 and the end cap 22, if the projections of the first blind hole portion 2211 and the second blind hole portion 2212 are circular, the contact with the lower plastic 26 is usually point contact or line contact, and the contact area is relatively small. However, by setting the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cap 22 to rectangles, the contact with the lower plastic 26 is usually surface contact, and the contact area is larger, which can improve the friction and constraint between the lower plastic 26 and the end cap 22. In addition, under the same perimeter conditions, the area of ​​the rectangular projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cap 22 is usually larger than the area of ​​the circle. This means that the rectangular blind hole 221 can provide a larger contact area in the direction perpendicular to the depth of the blind hole 221, which helps the hot melt column to contact the hole wall better, thereby improving the filling efficiency and solidification quality.

[0132] It should be understood that the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cap 22 can be squares or other polygons, as long as they can increase the contact area between the lower plastic 26 and the end cap 22, so that the two are firmly connected. This application does not impose any limitations on this.

[0133] In some embodiments, the first blind hole portion 2211 and the second blind hole portion 2212 can be in the shape of a cuboid or a cube, so that the hot melt column is in surface contact with the multiple hole walls of the first blind hole portion 2211 and the second blind hole portion 2212, thereby increasing the contact area between the two, increasing the contact area between the protrusion 261 and the lower plastic 26, and thus improving the stability between the protrusion 261 and the blind hole 221.

[0134] In some embodiments, the cross-sectional area of ​​the first blind hole portion 2211 and / or the second blind hole portion 2212 may gradually decrease or increase along the thickness direction of the end cap 22, providing a guiding structure for the protrusion 261 of the lower plastic 26, so that the protrusion 261 can enter the first blind hole portion 2211 and the second blind hole portion 2212.

[0135] In this embodiment, the blind hole 221 increases the pulling force on the lower plastic 26 through the larger first blind hole portion 2211 and the smaller second blind hole portion 2212. When the battery is subjected to external forces such as vibration or impact, the difference in cross-sectional area between the first blind hole portion 2211 and the second blind hole portion 2212 allows the blind hole to hold the protrusion 261 in place, enhancing the friction and constraint between them, preventing it from coming out of the blind hole 221, reducing the possibility of the lower plastic 26 being pulled off, and improving the stability of the battery cell. Furthermore, when the projection of the blind hole 221 is circular, the contact with the lower plastic 26 is usually a point contact or a line contact, and its contact area is relatively small, which is not conducive to the stability between the protrusion 261 and the blind hole 221. In this application, the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cap 22 are rectangular, which can make full use of the area of ​​the entire rectangle to contact the lower plastic 26, increase the contact area between the protrusion 261 and the lower plastic 26, and thus improve the stability between the protrusion 261 and the blind hole 221.

[0136] Figure 9 This is a cross-sectional view of another end cap 22 provided in an embodiment of this application.

[0137] like Figure 9 As shown, the first blind hole portion 2211 includes a first end face 2215 and a second end face 2216. The first end face 2215 is located on the side of the second end face 2216 away from the electrode assembly 25. From the first end face 2215 to the second end face 2216, the cross-sectional area of ​​the first blind hole portion 2211 gradually decreases along the thickness direction of the end cap 22.

[0138] In some embodiments, the first end face 2215 and the second end face 2216 are the end faces of the first blind hole portion 2211 along the thickness direction of the end cap 22, the first end face 2215 is the end face that coincides with the inner wall of the end cap 22, and the second end face 2216 is the end face that is connected to the second blind hole portion 2212.

[0139] It should be understood that the distance from the first end face 2215 to the second end face 2216 is along the thickness direction of the end cover 22 and points towards the electrode assembly 25.

[0140] In some embodiments, from the first end face 2215 to the second end face 2216, the cross-sectional area of ​​the first blind hole portion 2211 gradually decreases along the thickness direction of the end cap 22. For example, both the first end face 2215 and the second end face 2216 are rectangular, the first blind hole portion 2211 can be cuboid in shape, and the first end face 2215 to the second end face 2216 are inclined surfaces; as another example, from the first end face 2215 to the second end face 2216, the first blind hole portion 2211 presents a stepped shape with a gradually decreasing cross-section.

[0141] It should be understood that the first end face 2215 to the second end face 2216 can be a continuous surface.

[0142] For example, the vertical cross-section of the first blind hole portion 2211 can be trapezoidal.

[0143] In this embodiment, the gradually decreasing cross-sectional area of ​​the first blind hole portion 2211 provides a guiding structure for the protrusion 261 of the lower plastic 26, facilitating the protrusion 261's entry into the first blind hole portion 2211. When the protrusion 261 is a hot-melt column, the hot-melt column melts upon heating. The gradually decreasing cross-sectional area provides a backflow slope for the melting hot-melt column. As the hot-melt column gradually melts, the liquid hot-melt material flows along the second end face 2216 to the first end face 2215, filling the blind hole 221. This results in a tight and seamless connection between the hot-melt column and the blind hole 221 after solidification, enhancing the stability of the connection. In this way, the battery cell 20, after assembly, possesses a stable connection structure, improving the integrity and stability of the battery's internal structure.

[0144] Figure 10 This is a cross-sectional view of another end cap 22 provided in an embodiment of this application.

[0145] Optional, such as Figure 10 As shown, the two ends of the first blind hole portion 2211 away from the bottom of the electrode assembly 25 can be designed as rounded chamfers. This design can increase the flow capacity of the hot melt column during the hot melt process, thereby making the hot melt interface fuller.

[0146] Figure 11 This is a cross-sectional view of another end cap 22 provided in an embodiment of this application. Figure 12 This is a partial cross-sectional view of another end cap 22 provided in an embodiment of this application. Figure 13 This is a projection view of another end cap 22 provided in an embodiment of this application.

[0147] According to some embodiments of this application, optionally, such as Figures 11 to 13As shown, the blind hole 221 also includes a third blind hole portion 2213, which is located on the side of the second blind hole portion 2212 near the electrode assembly 25. The minimum area of ​​the third blind hole portion 2213 projected toward the end cap 22 is greater than the maximum area of ​​the second blind hole portion 2212 projected toward the end cap 22.

[0148] In some embodiments, the third blind hole portion 2213 is located on the side of the second blind hole portion 2212 near the electrode assembly 25. That is, when the protrusion 261 is connected to the blind hole 221, the protrusion 261 sequentially enters the third blind hole portion 2213, the second blind hole portion 2212 and the first blind hole portion 2211.

[0149] In this embodiment, the area of ​​the third blind hole portion 2213 projected toward the end cap 22 may not be a fixed value. The third blind hole portion 2213 may be a regular cuboid or cube. For example, if the third blind hole portion 2213 is a cuboid, it can fit tightly with the protrusion 261 and form multiple contact surfaces with the protrusion 261 for tight connection.

[0150] According to some embodiments of this application, optionally, the minimum area of ​​the third blind hole portion 2213 projected toward the end cap 22 is greater than the maximum area of ​​the second blind hole portion 2212 projected toward the end cap 22, that is, the cross-sectional area of ​​the third blind hole portion 2213 is greater than the cross-sectional area of ​​the second blind hole portion 2212. For example, the third blind hole portion 2213 can be a rectangular hole with a larger area, and the second blind hole portion 2212 can be a rectangular hole with a smaller area, forming a stepped structure between the two.

[0151] It should be understood that the third blind hole portion 2213 has a larger cross-sectional area. After the protrusion 261 is connected to the blind hole 221, as the contact area changes, the blind hole 221 can withstand greater tension, that is, the end cap 22 can withstand greater tension on the lower plastic 26.

[0152] Optionally, there can be multiple second blind holes 2212, and multiple second blind holes 2212 can form multiple stepped structures, maintaining a gradual decrease in cross-sectional area from one end near the first blind hole 2211 to one end near the third blind hole 2213, thereby forming multiple stepped structures, so that the blind hole 221 can withstand greater tensile force, and the end cap 22 can withstand greater tensile force on the lower plastic 26.

[0153] In this embodiment, the first blind hole portion 2211, the second blind hole portion 2212, and the third blind hole portion 2213 form a "multi-level nested" connection, similar to the multiple reinforcement design in a mortise and tenon structure. When the protrusion 261 is connected to the blind hole 221, the first blind hole portion 2211 and the second blind hole portion 2212 can withstand part of the tensile force on the lower plastic 26, improving the stability of the connection. When the battery cell 20 is subjected to external force, this structural design can effectively disperse and buffer stress, and the stress can be dispersed in multiple directions along the contact interface between the wall of the blind hole 221 and the protrusion 261. The connection structure composed of the first blind hole portion 2211, the second blind hole portion 2212, and the third blind hole portion 2213 can adapt to these dynamic changes and maintain the stability of the connection. In addition, a third blind hole 2213 is provided on the side of the second blind hole 2212 near the electrode assembly 25, and the minimum area of ​​the third blind hole 2213 projected toward the end cap 22 is greater than the maximum area of ​​the second blind hole 2212 projected toward the end cap. That is, the area of ​​the third blind hole 2213 that first contacts the protrusion 261 is designed to maximize the area that can be heated and reduce the power during heating. During assembly, the third blind hole 2213 provides a large initial entry space for the protrusion, making it easier for the protrusion 261 to enter the blind hole 221.

[0154] According to some embodiments of this application, optionally, such as Figure 13 As shown, the projection of the third blind hole portion 2213 toward the end cap 22 is rectangular.

[0155] It should be understood that the projection of the third blind hole portion 2213 toward the end cap 22 is rectangular. The shape of the third blind hole portion 2213 can be a cuboid, a cube, or a prism. For example, it can be a prism with a gradually increasing or decreasing cross-sectional area toward the end cap 22. Setting the shape of the third blind hole portion 2213 as a cuboid, a cube, or a prism allows multiple contact areas to be formed between the third blind hole portion 2213 and the hot melt pillar, enabling the end cap 22 to withstand greater tensile force, that is, the end cap 22 can withstand greater tensile force on the lower plastic 26.

[0156] In the embodiments of this application, during the initial contact between the protrusion 261 and the blind hole 221, if the projection of the third blind hole portion 2213 toward the end cover 22 is rectangular, the contact between the two is a surface contact. Therefore, compared with circular point contact or line contact, the technical solution of this application can increase the contact area between the two, thereby improving the stability between the protrusion 261 and the blind hole 221.

[0157] According to some embodiments of this application, optionally, the minimum area of ​​the third blind hole portion 2213 projected toward the end cap 22 is greater than the maximum area of ​​the first blind hole portion 2211 projected toward the end cap 22.

[0158] The minimum area of ​​the third blind hole portion 2213 projected toward the end cap 22 is greater than the maximum area of ​​the first blind hole portion 2211 projected toward the end cap 22, that is, the cross-sectional area of ​​the third blind hole portion 2213 is greater than the cross-sectional area of ​​the first blind hole portion 2211. For example, the third blind hole portion 2213 can be a rectangular hole with a larger cross-sectional area, and the first blind hole portion 2211 can be a rectangular hole with a smaller cross-sectional area.

[0159] Optionally, the cross-sectional area of ​​the third blind hole portion 2213 is larger than that of the first blind hole portion 2211 and the second blind hole portion 2212. In other words, designing the cross-sectional area of ​​the third blind hole portion 2213 to be larger increases the area of ​​heat fusion during heat fusion with the heat-fusion column, thus reducing the power required for heat fusion. Minimizing the cross-sectional area of ​​the second blind hole portion 2212 allows for a more secure connection between the heat-fusion column and the end cap 22. Simultaneously, designing the cross-sectional area of ​​the second blind hole portion 2212 to be larger provides a larger contact area with the heat-fusion column, resulting in a more stable connection.

[0160] In this embodiment, since the minimum area of ​​the third blind hole portion 2213 projected toward the end cap 22 is greater than the maximum area of ​​the first blind hole portion 2211 projected toward the end cap 22, the third blind hole portion 2213 provides a large initial entry space for the protrusion during assembly, which facilitates the protrusion entering the blind hole 221.

[0161] According to some embodiments of this application, optionally, the ratio L1 of the length to the width of the rectangle projected by the third blind hole portion 2213 toward the end cover 22 is in the range of 2≤L1≤4.

[0162] It should be understood that the ratio L1 of the length to the width of the rectangle can take the values ​​of 2, 2.5, 3, 3.5, and 4. In addition, the ratio L1 can be obtained through multiple experiments. For example, the range of the ratio L1 can be obtained by setting multiple third blind holes 2213 of different sizes on the end cap 22.

[0163] In this embodiment, if the ratio of the rectangle's length to its width is too large, i.e., the rectangle's area is too large, the flow of the protrusions during the hot-melting process may be difficult to control, making it hard to accurately fill the blind hole 221. This could lead to overflow into unwanted areas. Furthermore, uneven distribution of the protrusions 261 within the blind hole 221 will result in uneven density of the entire solidified component, affecting the stability of the battery cell. If the ratio of the rectangle's length to its width is too small, i.e., the rectangle's area is too small, the protrusions 261 may have difficulty flowing into the blind hole 221 during the hot-melting process. Additionally, a ratio that is too small may cause air to remain within the blind hole 221, forming bubbles and affecting the stability between the protrusions 261 and the blind hole 221.

[0164] Optionally, the length and width of the rectangle projected by the third blind hole portion 2213 toward the end cap 22 can be determined according to the length and width of the end cap 22. For example, the ratio of the length and width of the rectangle projected by the third blind hole portion 2213 toward the end cap 22 to the length and width of the end cap 22 is in the range of 1 / 50 to 1 / 10, so that the overall strength of the end cap 22 is not affected, while the blind hole 221 can play a good connecting role.

[0165] Optionally, the length and width of the rectangle projected by the third blind hole 2213 toward the end cap 22 can be greater than or equal to 3mm, so that the overall strength of the end cap 22 is not affected, while the blind hole 221 can play a good connecting role.

[0166] According to some embodiments of this application, optionally, the maximum area of ​​the protrusion 261 projected toward the end cap 22 is less than or equal to the minimum area of ​​the second blind hole portion 2212 projected toward the end cap 22.

[0167] In this embodiment, when the maximum area of ​​the protrusion 261 projected toward the end cap 22 is less than or equal to the minimum area of ​​the second blind hole portion 2212 projected toward the end cap 22, the protrusion 261 can easily and accurately align with and insert into the second blind hole portion 2212 during the assembly process of the end cap 22 and the lower plastic 26. This reduces the possibility that the end cap 22 and the lower plastic 26 cannot be connected due to the mismatch between the protrusion 261 and the blind hole 221, and shortens the assembly time of the end cap 22 and the lower plastic 26, thereby improving the assembly efficiency.

[0168] Figure 14 This is a cross-sectional view of another end cap 22 provided in an embodiment of this application.

[0169] According to some embodiments of this application, optionally, such as Figure 14 As shown, the first blind hole portion 2211 includes a first end face 2215 and a second end face 2216. The first end face 2215 is located on the side of the second end face 2216 away from the electrode assembly 25. From the first end face 2215 to the second end face 2216, the cross-sectional area of ​​the first blind hole portion 2211 gradually decreases along the thickness direction of the end cap 22.

[0170] In some embodiments, the first end face 2215 and the second end face 2216 are the end faces of the first blind hole portion 2211 along the thickness direction of the end cap 22, the first end face 2215 is the end face that coincides with the inner wall of the end cap 22, and the second end face 2216 is the end face that is connected to the second blind hole portion 2212.

[0171] It should be understood that the distance from the first end face 2215 to the second end face 2216 is along the thickness direction of the end cover 22 and points towards the electrode assembly 25.

[0172] In some embodiments, from the first end face 2215 to the second end face 2216, the cross-sectional area of ​​the first blind hole portion 2211 gradually decreases along the thickness direction of the end cap 22. For example, both the first end face 2215 and the second end face 2216 are rectangular, the first blind hole portion 2211 can be cuboid in shape, and the first end face 2215 to the second end face 2216 are inclined surfaces; as another example, from the first end face 2215 to the second end face 2216, the first blind hole portion 2211 presents a stepped shape with a gradually decreasing cross-section.

[0173] It should be understood that the first end face 2215 to the second end face 2216 can be a continuous surface.

[0174] For example, the vertical cross-section of the first blind hole portion 2211 can be trapezoidal.

[0175] In this embodiment, the gradually decreasing cross-sectional area of ​​the first blind hole portion 2211 provides a guiding structure for the protrusion 261 of the lower plastic 26, facilitating the protrusion 261's entry into the first blind hole portion 2211. When the protrusion 261 is a hot-melt column, the hot-melt column melts upon heating. The gradually decreasing cross-sectional area provides a backflow slope for the melting hot-melt column. As the hot-melt column gradually melts, the liquid hot-melt material flows along the second end face 2216 to the first end face 2215, filling the blind hole 221. This results in a tight and seamless connection between the hot-melt column and the blind hole 221 after solidification, enhancing the stability of the connection. In this way, the battery cell 20, after assembly, possesses a stable connection structure, improving the integrity and stability of the battery's internal structure.

[0176] According to some embodiments of this application, optionally, the dimension L2 of the blind hole 221 along the thickness direction of the end cap 22 is in the range of 0.5mm≤L2≤1.5mm.

[0177] It should be understood that the dimension L2 of the blind hole 221 along the thickness direction of the end cap 22 refers to the dimension of all blind holes 221 along the thickness direction of the end cap 22. For example, if the blind hole 221 includes a first blind hole portion 2211 and a second blind hole portion 2212, L2 refers to the dimension of the first blind hole portion 2211 and the second blind hole portion 2212 along the thickness direction of the end cap 22. As another example, if the blind hole 221 includes a first blind hole portion 2211, a second blind hole portion 2212, and a third blind hole portion 2213, L2 refers to the dimension L2 of the first blind hole portion 2211, the second blind hole portion 2212, and the third blind hole portion 2213 along the thickness direction of the end cap 22. Additionally, the dimension L2 of the blind hole 221 along the thickness direction of the end cap 22 can also refer to the maximum dimension of all blind holes 221 along the thickness direction of the end cap 22. For example... Figure 9 The L2 shown and, for example Figure 12 L2 is shown.

[0178] The dimension L2 of the blind hole 221 along the thickness direction of the end cap 22 can be set to 0.5mm, 0.8mm, 1.3mm, or 1.5mm.

[0179] In this embodiment, the dimension L2 of the blind hole 221 along the thickness direction of the end cap 22 is within 0.5mm to 1.5mm, which can improve the strength of the end cap 22 itself. If it is too large, the strength of the entire end cap 22 may be insufficient, which is not conducive to the integrity and stability of the battery cell. In addition, the dimension of the blind hole 221 along the thickness direction of the end cap 22 is within 0.5mm to 1.5mm, which can make the protrusion 261 and the blind hole 221 have a stable connection structure, improving the integrity and stability of the internal structure of the battery cell.

[0180] According to some embodiments of this application, optionally, the end cap 22 includes at least two blind holes 221, which are evenly distributed near the edge of the end cap 22.

[0181] For example, the end cap 22 may include a plurality of blind holes 221, which are evenly distributed.

[0182] It should be understood that the edge of end cap 22 refers to the outermost edge of end cap 22. For example, when end cap 22 is square, the edge of end cap 22 refers to the four sides of end cap 22.

[0183] It should be understood that "near the edge of end cap 22" refers to the outermost part of the surface of end cap 22, near the end cap 22.

[0184] According to some embodiments of this application, optionally, a plurality of blind holes 221 are evenly distributed near the edge of the end cap 22, meaning that along the outer side of the end cap 22, the distance between the plurality of blind holes 221 is equal. For example, the end cap 22 may include two blind holes 221, which may be located near two opposite sides of the end cap 22 and are symmetrically distributed; as another example, the end cap 22 may include four blind holes 221, which may be located near four sides of the end cap 22.

[0185] For example, when the end cap 22 includes an even number of blind holes 221, the blind holes 221 can be distributed in an axisymmetric manner.

[0186] Optionally, to ensure the overall tensile strength of the lower plastic 26 meets structural requirements, the number of blind holes 221 can be set to eight or more, distributed at intervals along the length of the end cap 22. Multiple blind holes 221 allow for a more secure connection between the end cap 22 and the lower plastic 26. Furthermore, the spacing between the multiple blind holes 221 can be less than or equal to 28 mm. This design allows for better interlocking between the end cap 22 and the lower plastic 26 without affecting the strength of the end cap 22. For example, the spacing between the multiple blind holes 221 can be set to 8 mm, 10 mm, 15 mm, 19 mm, 20 mm, or 28 mm. Additionally, the number of blind holes 221 can be determined based on the length of the end cap 22; this application does not impose any limitations on this.

[0187] In this embodiment, for the inverted electrode assembly 25 inside the battery cell 20, to prevent the lower plastic 26 from affecting the function of the pressure relief mechanism 24, there is no connection structure between the lower plastic 26 and the end cap 22. In this case, the blind holes 221 distributed around the end cap 22 bear the tension on the lower plastic 26.

[0188] In this embodiment, when the battery cell 20 is subjected to external impact, vibration, or pressure, the blind holes 221 evenly distributed near the edge can evenly disperse the stress at the edge of the end cap 22, effectively avoiding stress concentration and improving the deformation resistance of the end cap 22 and the stability of the overall structure. During assembly, the evenly distributed blind holes 221 provide positioning references, facilitating the assembly of various structures of the battery cell 20.

[0189] According to some embodiments of this application, optionally, the volume of the blind hole 221 is greater than or equal to the volume of the protrusion 261.

[0190] It should be understood that the volume of blind hole 221 is the sum of the volumes of each blind hole 221.

[0191] In some embodiments, provided that the end cap 22 and the lower plastic 26 are tightly connected, the volume of the blind hole 221 can be larger than the volume of the protrusion 261.

[0192] In some embodiments, the larger volume of the blind hole 221 allows the blind hole 221 to have enough space to accommodate the protrusion 261, so that even if there is slight shaking or displacement during insertion, it is not easy to cause wear or cracking of the protrusion 261 or the wall of the blind hole 221.

[0193] In this embodiment, the volume of the blind hole 221 is greater than or equal to the volume of the protrusion 261, allowing the blind hole 221 to accommodate the protrusion 261, thereby enabling a tight connection between the end cap 22 and the lower plastic 26. A suitable volume of the blind hole 221 provides more stable support for the protrusion 261. Furthermore, a suitable volume relationship between the blind hole 221 and the protrusion 261 helps improve the sealing performance of the battery cell 20. After the protrusion 261 is inserted into the blind hole 221, a tighter sealing structure can be formed between the two through a reasonable process.

[0194] Figure 15 This is a structural diagram of a lower plastic 26 provided in an embodiment of this application. Figure 16 This is a partial structural diagram of a lower plastic 26 provided in an embodiment of this application. Figure 17 This is a structural diagram of a protrusion 261 provided in an embodiment of this application. Figure 18 This is a structural diagram of another protrusion 261 provided in an embodiment of this application. (See diagram below.) Figures 15 to 18 As shown, the protrusion 261 includes a pyramidal head 2611 and a prismal body 2612. The maximum area of ​​the pyramidal head 2611 projected toward the end cap 22 is equal to the area of ​​the prismal body 2612 projected toward the end cap 22.

[0195] In some embodiments, when the projection of the blind hole 221 toward the end cap 22 is rectangular, the projection of the corresponding protrusion 261 toward the end cap 22 can also be rectangular.

[0196] According to some embodiments of this application, optionally, the maximum area of ​​the pyramidal head 2611 projected toward the end cap 22 is equal to the area of ​​the prismal main body 2612 projected toward the end cap 22, that is, the length and width of the base of the pyramidal head 2611 are equal to the length and width of the prismal main base.

[0197] For example, the pyramidal head 2611 can be a three-vertebral body, such as... Figures 15 to 17 As shown; it can also be a frustum shape, such as Figure 18 As shown, the larger base of the frustum coincides with the base of the prism-shaped main body 2612.

[0198] It should be understood that the maximum area of ​​the prism-shaped head facing the end cap 22 can be smaller than the area of ​​the prism-shaped body 2612 projected toward the end cap 22.

[0199] In this embodiment of the application, when the protrusion 261 is connected to the blind hole 221, the pyramidal head 2611 enters the blind hole 221 first, and the prismal body 2612 enters the blind hole 221 later.

[0200] In some embodiments, in order to ensure that the protrusion 261 fits tightly with the blind hole 221, the area of ​​the prism-shaped main body portion 2612 projected toward the end cap 22 can be the same as the area of ​​the second blind hole portion 2212 projected toward the end cap 22.

[0201] In this embodiment, the pyramidal head 2611 provides guidance for the protrusion 261 during assembly. When assembling the lower plastic 26 with the end cap 22, the pyramidal head 2611 can easily align with the entrance of the blind hole 221 of the end cap 22, and even if there is a certain positional deviation, the position can be smoothly corrected during insertion. The design that the maximum projected area of ​​the pyramidal head 2611 is equal to the projected area of ​​the prism-shaped main body 2612 ensures a smooth transition when inserting into the blind hole 221, without any jamming or assembly difficulties caused by abrupt changes in size.

[0202] According to some embodiments of this application, optionally, such as Figure 17 As shown, the angle between the side edge of the pyramidal head 2611 and the bottom surface near the prismal body 2612. The scope is:

[0203] It should be understood that The value can be 30°, 40°, 50°, or 60°.

[0204] The lateral edges of the pyramidal head 2611 are line segments connecting the apex of the pyramidal head 2611 to each vertex of the base.

[0205] In this embodiment, the angle between the side edge of the pyramidal head 2611 and the bottom surface near the prismal body 2612 is... An angle between 30° and 60° allows for better connection between the protrusion 261 and the blind hole 221, improving the stability of the battery cell. An excessively large angle may reduce the contact area between the pyramidal head 2611 and the opening of the blind hole 221, making it difficult for the protrusion 261 to smoothly enter the blind hole. Conversely, an excessively small angle will slow down the speed at which the protrusion enters the blind hole 221, reducing production efficiency.

[0206] Optionally, the material of protrusion 261 includes: polyamide, polycarbonate, polypropylene, or epoxy resin.

[0207] It should be understood that polyamide has good mechanical properties, including high strength and toughness. It can withstand a certain degree of tension, bending, and impact, which makes the protrusion 261 less prone to breakage under external force. Its melting point is usually between 200-300℃. When the temperature reaches the melting point range, the polyamide can melt rapidly and uniformly, allowing the protrusion 261 to quickly and stably fill the blind hole 221 during the connection process, achieving a tight bond between the lower plastic 26 and the end cap 22.

[0208] It should be understood that polycarbonate has good thermal stability and can maintain stable performance over a wide temperature range, with a melting point generally around 220-250℃. During the heating and melting process of protrusion 261, it can maintain a stable liquid state over a wide temperature range and is not prone to decomposition or carbonization. After melting, polycarbonate can rapidly cool and solidify when the temperature drops. Rapid cooling and solidification allows protrusion 261 to quickly set, reducing deformation or displacement that may occur due to prolonged liquid state, thus ensuring the accuracy and stability of the connection.

[0209] It should be understood that polypropylene has a low density and is a lightweight material. Its melting point is approximately between 160-170℃. This lower melting point means less energy is required during the heating process of the hot melt column, reducing energy costs in the manufacturing process. Molten polypropylene possesses good melt strength, maintaining a certain shape when filling the blind holes 221 of the end caps 22, and is less prone to flowing or collapsing. This ensures the accuracy and stability of the connection during the hot melt column connection process.

[0210] It should be understood that epoxy resin has excellent bonding properties and can firmly bond with a variety of materials. After curing, it forms a highly cross-linked three-dimensional network structure with high hardness and strength, while also exhibiting good chemical resistance and electrical insulation. The curing process of epoxy resin usually requires the use of a curing agent, and the curing temperature varies depending on the formulation, generally ranging from 80-150℃.

[0211] In this embodiment, polyamide, polycarbonate, polypropylene, or epoxy resin is used as the material for the protrusion 261. After melting, it can fill the blind holes 221, enhancing connection reliability and the safety of the battery cell 20 due to its high bonding strength, good mechanical properties, and sealing performance. Its hot-melt characteristics are easy to control, and it has high dimensional accuracy after curing or cooling. It is adaptable to different production processes, can efficiently complete the connection operation, and can maintain stable performance under different temperature conditions, thus improving the stability of the battery cell 20.

[0212] According to some embodiments of this application, this application also provides a battery device 100, which includes a plurality of battery cells 20 and a battery housing 10, wherein the plurality of battery cells 20 are housed in the battery housing 10. Each battery cell 20 includes a housing 21, an electrode assembly 25, a lower plastic 26, and an end cap 22. The housing 21 includes an opening 211. The electrode assembly 25 is housed in the housing 21. The lower plastic 26 covers the opening 211 and includes a protrusion 261 located on the side of the lower plastic 26 away from the electrode assembly 25. The end cap 22 is connected to the lower plastic 26 to close the opening 211. The end cap 22 includes a blind hole 221 located on the side of the end cap 22 near the protrusion 261, and the blind hole 221 engages with the protrusion 261. The blind hole 221 includes a first blind hole portion 2211 and a second blind hole portion 2212. The first blind hole portion 2211 is located on the side of the second blind hole portion 2212 away from the electrode assembly 25. The maximum area of ​​the first blind hole portion 2211 projected toward the end cover 22 is greater than the maximum area of ​​the second blind hole portion 2212 projected toward the end cover 22, and the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cover 22 are rectangular.

[0213] It should be understood that the battery cell 20 may also be the battery cell 20 of any of the above embodiments.

[0214] In this embodiment, the battery housing 10 may be made of one or more materials. For example, it may include high-strength metallic materials, such as aluminum alloys or steel, to provide good structural strength and stability and ensure the safety of the battery in various environments; it may also include non-metallic materials with excellent insulation properties, such as engineering plastics, to reduce the possibility of safety hazards such as battery leakage; and it may also include materials with good thermal conductivity to facilitate heat dissipation during battery operation and maintain the normal operating temperature of the battery.

[0215] According to some embodiments of this application, this application also provides an electrical device, which includes a battery device 100 for providing electrical energy. The battery device 100 includes a plurality of battery cells 20, each battery cell 20 including a housing 21, an electrode assembly 25, a lower plastic 26, and an end cap 22. The housing 21 includes an opening 211; the electrode assembly 25 is housed within the housing 21; the lower plastic 26 covers the opening 211 and includes a protrusion 261 located on the side of the lower plastic 26 away from the electrode assembly 25; the end cap 22 is connected to the lower plastic 26 to close the opening 211, and the end cap 22 includes a blind hole 221 located at the end cap. On the side of the cover 22 near the protrusion 261, the blind hole 221 engages with the protrusion 261; wherein, the blind hole 221 includes a first blind hole portion 2211 and a second blind hole portion 2212, the first blind hole portion 2211 is located on the side of the second blind hole portion 2212 away from the electrode assembly 25, the maximum area of ​​the first blind hole portion 2211 projected toward the end cover 22 is greater than the maximum area of ​​the second blind hole portion 2212 projected toward the end cover 22, and the projections of the first blind hole portion 2211 and the second blind hole portion 2212 toward the end cover 22 are rectangular.

[0216] It should be understood that the battery cell 20 may also be the battery cell 20 of any of the above embodiments.

[0217] According to some embodiments of this application, see Figures 3 to 18 This application provides a battery cell 20, which includes a housing 21, an electrode assembly 25, a lower plastic 26, and an end cap 22. The housing 21 includes an opening 211; the electrode assembly 25 is housed in the housing 21; the lower plastic 26 covers the opening 211 and includes a protrusion 261 located on the side of the lower plastic 26 away from the electrode assembly 25; the end cap 22 is connected to the lower plastic 26 to close the opening 211, and the end cap 22 includes a blind hole 221 located on the end cap 211. 2. Near the protrusion 261, a blind hole 221 engages with the protrusion 261. The blind hole 221 includes a first blind hole portion 2211 and a second blind hole portion 2212. The first blind hole portion 2211 is located on the side of the second blind hole portion 2212 away from the electrode assembly 25. The maximum area projected by the first blind hole portion 2211 toward the end cap 22 is greater than the maximum area projected by the second blind hole portion 2212 toward the end cap 22, and the projections of both the first and second blind hole portions 2211 toward the end cap 22 are rectangular. The blind hole 221 also includes a third blind hole portion 2213, located on the side of the second blind hole portion 2212 near the electrode assembly 25. The minimum area projected by the third blind hole portion 2213 toward the end cap 22 is greater than the maximum area projected by the second blind hole portion 2212 toward the end cap 22. The projection of the third blind hole portion 2213 toward the end cap 22 is rectangular. The volume of blind hole 221 is greater than or equal to the volume of protrusion 261.

[0218] The protrusion 261 includes a pyramidal head 2611 and a prismal body 2612. The maximum area of ​​the pyramidal head 2611 projected toward the end cap 22 is equal to the area of ​​the prismal body 2612 projected toward the end cap 22.

[0219] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: A housing (21), the housing (21) including an opening (211); Electrode assembly (25), the electrode assembly (25) being housed in the housing (21); A lower plastic (26) that covers the opening (211) includes a protrusion (261) located on the side of the lower plastic (26) away from the electrode assembly (25). End cap (22), the end cap (22) is connected to the lower plastic (26) to cover the opening (211), the end cap (22) includes a blind hole (221), the blind hole (221) is located on the side of the end cap (22) near the protrusion (261), the blind hole (221) engages with the protrusion (261); The blind hole (221) includes a first blind hole portion (2211) and a second blind hole portion (2212). The first blind hole portion (2211) is located on the side of the second blind hole portion (2212) away from the electrode assembly (25). The maximum area of ​​the first blind hole portion (2211) projected toward the end cap (22) is greater than the maximum area of ​​the second blind hole portion (2212) projected toward the end cap (22). The projections of the first blind hole portion (2211) and the second blind hole portion (2212) toward the end cap (22) are rectangular.

2. The battery cell according to claim 1, characterized in that, The blind hole (221) also includes a third blind hole portion (2213), which is located on the side of the second blind hole portion (2212) near the electrode assembly (25). The minimum area of ​​the third blind hole portion (2213) projected toward the end cap (22) is greater than the maximum area of ​​the second blind hole portion (2212) projected toward the end cap (22).

3. The battery cell according to claim 2, characterized in that, The projection of the third blind hole (2213) toward the end cap (22) is rectangular.

4. The battery cell according to claim 2, characterized in that, The minimum area of ​​the third blind hole portion (2213) projected toward the end cap (22) is greater than the maximum area of ​​the first blind hole portion (2211) projected toward the end cap (22).

5. The battery cell according to claim 2, characterized in that, The ratio L1 of the length to width of the rectangle projected by the third blind hole (2213) toward the end cap (22) is in the range of 2≤L1≤4.

6. The battery cell according to claim 1, characterized in that, The maximum area of ​​the protrusion (261) projected toward the end cap (22) is less than or equal to the minimum area of ​​the second blind hole portion (2212) projected toward the end cap (22).

7. The battery cell according to claim 1, characterized in that, The first blind hole portion (2211) includes a first end face (2215) and a second end face (2216). The first end face (2215) is located on the side of the second end face (2216) away from the electrode assembly (25). From the first end face (2215) to the second end face (2216), the cross-sectional area of ​​the first blind hole portion (2211) gradually decreases along the thickness direction of the end cap (22).

8. The battery cell according to any one of claims 1 to 7, characterized in that, The dimension L2 of the blind hole (221) along the thickness direction of the end cap (22) is in the range of 0.5mm≤L2≤1.5mm.

9. The battery cell according to any one of claims 1 to 7, characterized in that, The end cap (22) includes at least two blind holes (221), which are evenly distributed near the edge of the end cap (22).

10. The battery cell according to any one of claims 1 to 7, characterized in that, The volume of the blind hole (221) is greater than or equal to the volume of the protrusion (261).

11. The battery cell according to any one of claims 1 to 7, characterized in that, The protrusion (261) includes a pyramidal head (2611) and a prismal body (2612), the maximum area of ​​the pyramidal head (2611) projected toward the end cap (22) is equal to the area of ​​the prismal body (2612) projected toward the end cap (22).

12. The battery cell according to claim 11, characterized in that, The angle between the side edge of the pyramidal head (2611) and the bottom surface near the prismal body (2612) The scope is:

13. The battery cell according to claim 11, characterized in that, The maximum area of ​​the prismatic main body (2612) projected toward the end cap (22) is less than or equal to the minimum area of ​​the second blind hole (2212) projected toward the end cap (22).

14. A battery device, characterized in that, include: Multiple battery cells; the multiple battery cells include the battery cells according to any one of claims 1 to 13; A battery housing (10) in which the plurality of battery cells are housed.

15. An electrical appliance, characterized in that, include: A battery device, comprising the battery device according to claim 14, the battery device being used to provide electrical energy.

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