Battery cell, end cap assembly, battery device, and electric device

Abstract

This application relates to the field of battery technology, and proposes a battery cell, an end cap assembly, a battery device, and an electrical device. The battery cell includes a casing, an electrode assembly, an end cap, electrode terminals, and a fixing member. The end cap closes to the opening and includes a base layer and a reinforcing layer stacked along the thickness direction of the end cap. The reinforcing layer is disposed on the side of the base layer facing away from the electrode assembly. The electrode terminals are disposed on the end cap and electrically connected to the electrode assembly. The fixing member includes a fixing part, a first main body part, and a first connecting part connected to each other. The fixing part is parallel to the end cap and abuts against the side of the electrode terminals facing away from the electrode assembly. The first main body part is disposed around the electrode terminals. The first connecting part is connected to the reinforcing layer. The matrix material of the reinforcing layer is the same as the matrix material of the fixing member, and the strength of the matrix material of the reinforcing layer is stronger than the strength of the matrix material of the base layer. The technical solution provided by the embodiments of this application improves the energy density of the battery cell by improving the structure of the end cap and electrode terminals.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell, end cap assembly, battery device, and electrical equipment. Background Technology

[0002] End caps and electrode terminals are important components of a battery. Their design not only affects the battery's sealing, safety, and connection reliability, but also its energy density and other performance characteristics. If the structure and dimensions of the end caps and electrode terminals are not designed properly, they may encroach on the available space of core energy storage components such as electrodes and electrolytes, reducing the battery's effective energy storage volume and ultimately leading to a decrease in the battery's energy density. Utility Model Content

[0003] In view of this, embodiments of this application provide a battery cell, an end cap assembly, a battery device, and an electrical device, which improve the energy density of the battery cell by improving the structure of the end cap and electrode terminals.

[0004] An embodiment of the first aspect of this application provides a battery cell, comprising: a housing having an opening and an internal accommodating space; an electrode assembly disposed within the accommodating space; an end cap covering the opening, the end cap comprising a base layer and a reinforcing layer stacked along the thickness direction of the end cap, the reinforcing layer being disposed on the side of the base layer facing away from the electrode assembly; an electrode terminal disposed on the end cap and electrically connected to the electrode assembly; and a fixing member comprising a fixing portion, a first main body portion, and a first connecting portion connected thereto, the fixing portion being parallel to the end cap and abutting against the side of the electrode terminal facing away from the electrode assembly, the first main body portion being disposed around the electrode terminal, and the first connecting portion being connected to the reinforcing layer; wherein the base material of the reinforcing layer is the same as the base material of the fixing member, and the strength of the base material of the reinforcing layer is stronger than the strength of the base material of the base layer.

[0005] The battery cell provided in this embodiment includes an end cap comprising a base layer and a reinforcing layer disposed on the base layer. The strength of the matrix material of the reinforcing layer is greater than that of the matrix material of the base layer. By replacing part of the base layer structure with the reinforcing layer, the overall thickness of the end cap can be reduced while maintaining the overall strength of the end cap, thereby reducing the space occupied by the end cap. The matrix material of the fastener is the same as that of the reinforcing layer. By increasing the strength of the matrix material of the fastener, the thickness of the fastening part can be reduced while maintaining the overall strength of the fastener, thereby reducing the overall size of the fastener. This reduces the constraint of the fastener on the height of the electrode terminals, allowing the electrode terminals to be designed with a lower height, thereby reducing the space occupied by the electrode terminals. By reducing the space occupied by the end cap and electrode terminals in the battery cell, more usable space can be provided for electrode components, electrolyte, etc., thereby increasing the energy density of the battery cell.

[0006] In some embodiments, the outer edge of the electrode terminal on the side opposite to the electrode assembly is provided with a slot, and the fixing part is at least partially disposed in the slot.

[0007] In the above embodiments, by providing a slot on the electrode terminal to accommodate the fixing component, it is beneficial to reduce the overall height of the electrode terminal and the fixing component, thereby further reducing the space occupied by the electrode terminal and the fixing component.

[0008] In some embodiments, the tensile strength of the matrix material of the base layer is T1, the tensile strength of the matrix material of the reinforcing layer is T2, and 1≤T2 / T1≤10.

[0009] In the above embodiments, by limiting the ratio of tensile strength between the substrate material of the base layer and the substrate material of the reinforcing layer, the strength design requirements and thickness design requirements of the end cap can be balanced, thereby keeping the thickness of the base layer and the reinforcing layer in the end cap within a reasonable range. This can both improve the energy density of the battery cell and help reduce the processing difficulty of the end cap.

[0010] In some embodiments, the yield strength of the matrix material of the base layer is σ1, the yield strength of the matrix material of the reinforcing layer is σ2, and 1≤σ2 / σ1≤4.

[0011] In the above embodiments, by limiting the ratio of yield strength between the substrate material of the base layer and the substrate material of the reinforcing layer, the strength design requirements and thickness design requirements of the end cap can be balanced, thereby keeping the thickness of the base layer and the reinforcing layer in the end cap within a reasonable range. This can both improve the energy density of the battery cell and help reduce the processing difficulty of the end cap.

[0012] In some embodiments, the thickness of the end cap is H, and the thickness of the reinforcing layer is H1, where 5% ≤ (H1 / H) × 100% ≤ 40%.

[0013] In the above embodiments, by limiting the thickness ratio of the reinforcing layer, it is helpful to achieve the best match between the end cap strength, weight and manufacturing process, which not only improves the overall performance of the battery cell, but also helps to reduce the processing difficulty of the end cap.

[0014] In some embodiments, the base layer is an aluminum layer and the reinforcing layer is a steel layer.

[0015] In the above embodiments, the tensile strength and yield strength of steel are significantly higher than those of aluminum. Laying a steel layer on the surface of the aluminum layer can effectively improve the strength of the end cap, or reduce the thickness of the end cap while ensuring the same strength. Aluminum and steel are chemically stable, and the two are not prone to chemical reactions and corrosion problems after being combined.

[0016] In some embodiments, the base material of the base layer is the same as the base material of the shell.

[0017] In the above embodiments, the shell and the base layer are designed to be made of the same material to ensure that the contact surfaces of the two have similar physical properties such as melting point and coefficient of thermal expansion. In this way, when the two are connected and fixed by welding, welding defects caused by material differences can be reduced during the welding process, thereby improving the reliability and bonding strength of the welded connection between the shell and the base layer.

[0018] In some embodiments, a reinforcing layer is laid on the entire surface of the base layer facing away from the electrode assembly, and the outer edge of the base layer facing the electrode assembly is welded to the end face of the housing.

[0019] In the above embodiments, an end cap suitable for side-welded connections is provided. The composite structure of the base layer and the reinforcing layer in the end cap is simple and easy to process and manufacture.

[0020] In some embodiments, the outer edge of the substrate layer facing the electrode assembly is provided with a continuous positioning groove, which is used to accommodate part of the housing, and the bottom wall of the positioning groove is welded to the end face of the housing.

[0021] In the above embodiments, the positioning groove can provide precise positioning for the assembly of the end cap and the housing, thereby reducing the assembly error between the end cap and the housing. At the same time, the design of the positioning groove also allows part of the end cap to be housed in the housing, reducing the space occupied by the end cap, thereby helping to reduce the overall volume of the battery cell or increase the energy density of the battery cell.

[0022] In some embodiments, the thickness of the base layer at the location where it is used to connect to the housing is greater than or equal to 0.3 mm.

[0023] In the above embodiments, by reasonably limiting the thickness of the base layer in the connection area, the connection strength and reliability between the end cap and the shell can be improved.

[0024] In some embodiments, a receiving groove is provided on the side of the base layer facing away from the electrode assembly, a reinforcing layer is laid in the receiving groove, and the outer peripheral surface of the base layer is welded to the inner wall of the housing.

[0025] In the above embodiments, an end cap suitable for top-welded connections is provided, wherein the base layer and the reinforcing layer in the end cap are embedded and fitted together, resulting in higher structural stability.

[0026] In some embodiments, the wall thickness of the receiving groove is 0.5mm-5mm.

[0027] In the above embodiments, by reasonably limiting the wall thickness of the mounting groove, the connection strength and reliability between the end cap and the housing can be improved.

[0028] In some embodiments, the battery cell includes an insulating element, which is at least partially disposed between the electrode terminals and the fixing element.

[0029] In the above embodiments, by providing insulating components, electrical insulation can be maintained between the electrode terminals and the metal parts on the end cap, thereby reducing the risk of electrical damage such as short circuits.

[0030] In some embodiments, the insulating element covers the exterior of the fixing portion and the first body portion.

[0031] In the above embodiments, the insulating component has a good insulating effect and can fit tightly with the electrode terminals and end caps, thereby improving the sealing performance at the electrode terminals.

[0032] In some embodiments, the end cap is provided with a liquid injection hole, and the battery cell includes a first sealing pin that covers the liquid injection hole. The base material of the first sealing pin is the same as the base material of the reinforcing layer.

[0033] In the above embodiments, the first sealing nail and the reinforcing layer are designed to be made of the same material, which can avoid the chemical reaction that occurs after the two are assembled and cause corrosion problems. Furthermore, the two can be connected and fixed by welding, thereby having higher connection strength and good sealing performance.

[0034] An embodiment of the second aspect of this application provides an end cap assembly, including: an end cap, comprising a base layer and a reinforcing layer stacked along the thickness direction of the end cap; an electrode terminal disposed on the end cap; and a fastener, comprising a fastening portion, a first main body portion, and a first connecting portion connected to each other, wherein the fastening portion is parallel to the end cap and abuts against the side of the electrode terminal facing away from the end cap, the first main body portion is disposed around the electrode terminal, and the first connecting portion is connected to the reinforcing layer; wherein the matrix material of the reinforcing layer is the same as the matrix material of the fastener, and the strength of the matrix material of the reinforcing layer is stronger than the strength of the matrix material of the base layer.

[0035] The end cap assembly provided in this application improves the structure of the end cap and the fixing member, thereby reducing the end cap thickness and the electrode terminal height. When the end cap assembly is applied to a battery cell, since the end cap and electrode terminals occupy less space, more usable space can be provided for the electrode assembly and electrolyte, thereby effectively increasing the energy density of the battery cell.

[0036] In some embodiments, the tensile strength of the matrix material of the base layer is T1, the tensile strength of the matrix material of the reinforcing layer is T2, and 1≤T2 / T1≤10.

[0037] In the above embodiments, by limiting the ratio of tensile strength between the substrate material of the base layer and the substrate material of the reinforcing layer, the strength design requirements and thickness design requirements of the end cap can be balanced, thereby keeping the thickness of the base layer and the reinforcing layer in the end cap within a reasonable range. This can both improve the energy density of the battery cell and help reduce the processing difficulty of the end cap.

[0038] In some embodiments, the yield strength of the matrix material of the base layer is σ1, the yield strength of the matrix material of the reinforcing layer is σ2, and 1≤σ2 / σ1≤4.

[0039] In the above embodiments, by limiting the ratio of yield strength between the substrate material of the base layer and the substrate material of the reinforcing layer, the strength design requirements and thickness design requirements of the end cap can be balanced, thereby keeping the thickness of the base layer and the reinforcing layer in the end cap within a reasonable range. This can both improve the energy density of the battery cell and help reduce the processing difficulty of the end cap.

[0040] In some embodiments, the thickness of the end cap is H, and the thickness of the reinforcing layer is H1, where 5% ≤ (H1 / H) × 100% ≤ 40%.

[0041] In the above embodiments, by limiting the thickness ratio of the reinforcing layer, it is helpful to achieve the best match between the end cap strength, weight and manufacturing process, which not only improves the overall performance of the battery cell, but also helps to reduce the processing difficulty of the end cap.

[0042] In some embodiments, the base layer is an aluminum layer and the reinforcing layer is a steel layer.

[0043] In the above embodiments, the tensile strength and yield strength of steel are significantly higher than those of aluminum. Laying a steel layer on the surface of the aluminum layer can effectively improve the strength of the end cap, or reduce the thickness of the end cap while ensuring the same strength. Aluminum and steel are chemically stable, and the two are not prone to chemical reactions and corrosion problems after being combined.

[0044] An embodiment of the third aspect of this application provides a battery device including the battery cell of the first aspect.

[0045] The battery device provided in this application improves the energy density and overall performance of the battery device by using the battery cells in the first aspect.

[0046] An embodiment of the fourth aspect of this application provides an electrical device, including a battery cell as described in the first aspect or a battery device as described in the third aspect, wherein the battery cell or battery device is used to store or provide electrical energy.

[0047] The electrical equipment provided in this application improves the battery life and usability by using the battery cells in the first aspect or the battery devices in the third aspect.

[0048] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the vehicle structure provided in the embodiments of this application;

[0051] Figure 2 This is an exploded view of the battery device provided in the embodiments of this application;

[0052] Figure 3 These are exploded views of a single battery cell provided in some embodiments of this application;

[0053] Figure 4 These are exploded views of a battery cell provided in other embodiments of this application;

[0054] Figure 5 These are cross-sectional views of a battery cell provided in some embodiments of this application;

[0055] Figure 6 yes Figure 5 Enlarged view of the structure shown in Figure A;

[0056] Figure 7 This is an exploded view of an end cap assembly provided in some embodiments of this application;

[0057] Figure 8 These are front views of a battery cell provided in some embodiments of this application;

[0058] Figure 9 This is a side view of a battery cell provided in some embodiments of this application;

[0059] Figure 10 This is a top view of a battery cell provided in some embodiments of this application;

[0060] Figure 11 yes Figure 5 Enlarged view of the structure shown in B;

[0061] Figure 12 This is a cross-sectional view of a battery cell provided in other embodiments of this application;

[0062] Figure 13 This is a top view of a battery cell provided in other embodiments of this application;

[0063] Figure 14 This is a schematic diagram of the end cap structure provided in some embodiments of this application;

[0064] Figure 15 yes Figure 12 Enlarged view of the structure shown in C;

[0065] Figure 16 yes Figure 5 An enlarged view of the structure shown in D.

[0066] The markings in the diagram mean:

[0067] 1000, Vehicle; 100, Battery unit; 200, Controller; 300, Motor;

[0068] 10. Box; 11. First box; 12. Second box;

[0069] 20. Battery cell; 21. Housing; 211. Opening; 22. Electrode assembly; 22a. Tab; 23. End cap assembly; 231. End cap; 2311. Base layer; 2312. Reinforcing layer; 2313. Mounting hole; 2314. Mounting groove; 2315. Positioning groove; 2316. Injection hole; 23161. First hole segment; 23162. Second hole segment; 232. Electrode terminal; 2321. Slot; 233. Fixing member; 2331. Fixing part; 2332. First main body part; 2334. First connecting part; 234. Insulating member; 2341. Boss; 235. First sealing pin; 2351. Second main body part; 2352. Second connecting part; 2353. Buffer part; 236. Second sealing pin; 237. Sealing member; 238. Pressure relief mechanism; 239. Lower plastic. Detailed Implementation

[0070] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0072] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0073] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0074] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0075] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0076] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0077] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0078] In battery design, the structure and dimensions of the end caps and electrode terminals affect the overall performance of the battery. On the one hand, the design of the end caps and electrode terminals needs to meet the requirements of airtightness, mechanical strength, and insulation, so that the battery can be used for a long time without safety risks such as electrolyte leakage, short circuits, or mechanical failure. On the other hand, the end caps and electrode terminals occupy internal or external space of the battery, creating rigid constraints on the internal layout. While meeting the requirements of sealing, safety, and connection reliability, it is also necessary to optimize the structural design of the end caps and electrode terminals to maximize the internal space of the battery and improve its energy density.

[0079] In related designs, electrode terminals are fixed to the end cap via structures such as welding rings. The welding rings and end caps are made of the same material and are welded together. The material and shape of the welding rings affect their structural strength, which in turn affects the connection strength between the electrode terminals and the end caps. To improve the reliability of the welding rings, they generally need to be designed with a greater thickness, which leads to an increase in the overall height of the welding rings. The height design of the welding rings, in turn, imposes limitations on the structure of the electrode terminals, requiring them to be designed with a relatively high height to fit the welding ring structure. However, excessively high electrode terminals will encroach on the usable space of core energy storage components such as electrodes and electrolytes, reducing the effective internal volume of the battery and thus affecting its energy density.

[0080] For the reasons mentioned above, this application provides a battery cell including a housing, an electrode assembly, an end cap, electrode terminals, and a fixing member. The end cap covers the opening of the housing and includes a base layer and a reinforcing layer stacked along the thickness direction of the end cap. By replacing part of the base layer with the reinforcing layer, the overall thickness of the end cap can be reduced while maintaining the overall strength of the end cap, thereby reducing the space occupied by the end cap. The electrode terminals are disposed on the end cap and electrically connected to the electrode terminals inside the housing. The fixing member includes a fixing part, a first main body part, and a first connecting part connected to each other. The fixing part is parallel to the end cap and abuts against the side of the electrode terminal facing away from the electrode assembly. The first fixing part is disposed around the electrode terminal, and the first connecting part is connected to the reinforcing layer. The base material of the fixing member is the same as the base material of the reinforcing layer. Thus, by increasing the strength of the base material of the fixing member, the overall size of the fixing member can be reduced while maintaining the overall strength of the fixing member. This reduces the constraint of the fixing member on the height of the electrode terminals, allowing the electrode terminals to be designed with a lower height, thereby reducing the space occupied by the electrode terminals. The above solution reduces the space occupied by the end caps and electrode terminals in the battery cell, thus providing more usable space for electrode components, electrolyte, etc., thereby increasing the energy density of the battery cell.

[0081] The battery device provided in this application embodiment can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. The electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0082] For ease of explanation, this application uses a vehicle 1000 as an example of an electrical device.

[0083] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0084] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0085] Please refer to Figure 2 , Figure 2This is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first housing 11 and a second housing 12, which overlap each other, collectively defining a space for accommodating the battery cell 20. The second housing 12 may be a hollow structure with an opening 211 at one end, while the first housing 11 may be a plate-like structure, covering the opening 211 side of the second housing 12 so that the first housing 11 and the second housing 12 jointly define the space. Alternatively, both the first housing 11 and the second housing 12 may be hollow structures with an opening 211 on one side, with the opening 211 side of the first housing 11 overlapping the opening 211 side of the second housing 12. Of course, the box 10 formed by the first box 11 and the second box 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0086] In some embodiments, the housing 10 may be part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 may be at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 may be at least a portion of the crossbeams and longitudinal beams of the vehicle 1000.

[0087] In some embodiments, the battery device 100 may not include the housing 10, but instead connect multiple battery cells 20 and assemble them into the vehicle 1000 after forming a whole by necessary fixing structures.

[0088] In the battery device 100, there can be multiple battery cells 20. These multiple battery cells 20 can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, multiple battery cells 20 can first be connected in series, parallel, or in a mixed configuration to form a battery cell assembly, and then the battery cell assemblies can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. The battery device 100 may also include other structures; for example, the battery device 100 may also include a busbar component for realizing the electrical connection between the multiple battery cells 20.

[0089] A battery cell 20 refers to the smallest unit that makes up the battery device 100. Each battery cell 20 can be a rechargeable battery, meaning that after the battery cell 20 has been discharged, the active materials can be activated by charging to continue its use. The battery cell 20 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., but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0090] Please refer to Figure 3 , Figure 3 This is an exploded view of a battery cell 20 provided in some embodiments of this application. The battery cell 20 includes an end cap 231, a housing 21, an electrode assembly 22, and other functional components.

[0091] End cap 231 refers to a component that covers the opening 211 of housing 21 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 231 can be adapted to the shape of housing 21 to fit it. Optionally, end cap 231 can be made of a material with certain hardness and strength, so that end cap 231 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved safety performance. Functional components such as electrode terminals 232 can be provided on end cap 231. Electrode terminals 232 can be used for electrical connection with electrode assembly 22 for outputting or inputting electrical energy into battery cell 20. In some embodiments, end cap 231 can also be provided with a pressure relief mechanism 238 for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 231 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, an insulating component may be provided on the inner side of the end cap 231. The insulating component can be used to isolate the electrical connection components within the housing 21 from the end cap 231 to reduce the risk of short circuits. For example, the insulating component may be made of plastic, rubber, etc.

[0092] The housing 21 is a component used to cooperate with the end cap 231 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 21 and the end cap 231 can be independent components. An opening 211 can be provided on the housing 21, and the end cap 231 can close the opening 211 to form the internal environment of the battery cell 20. Alternatively, the end cap 231 and the housing 21 can be integrated. Specifically, the end cap 231 and the housing 21 can form a common connecting surface before other components are inserted into the housing 21. When it is necessary to encapsulate the interior of the housing 21, the end cap 231 closes the housing 21. The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 22. The housing 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0093] Electrode assembly 22 is the component in the battery cell 20 where electrochemical reactions occur. The casing 21 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator may also be provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 22, while the portions of the positive and negative electrode sheets without active material each constitute a tab 22a. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 22a connect to the electrode terminals 232 to form a current loop.

[0094] The technical solutions provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0095] Please refer to Figures 4-7 , Figure 4 This is an exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. Figure 6 for Figure 5 An enlarged view of the structure shown in diagram A. Figure 7This is an exploded view of an end cap assembly 23 provided in some embodiments of this application. An embodiment of a first aspect of this application provides a battery cell 20, including a housing 21, an electrode assembly 22, an end cap 231, electrode terminals 232, and a fastener 233. The housing 21 has an opening 211, and the interior of the housing 21 has a receiving space. The electrode assembly 22 is disposed within the receiving space of the housing 21. End cap 231 covers the opening 211 of housing 21. End cap 231 includes a base layer 2311 and a reinforcing layer 2312 stacked along the thickness direction of end cap 231. Electrode terminal 232 is disposed on end cap 231 and electrically connected to electrode assembly 22. Fixing member 233 includes a fixing part 2331, a first main body part 2332 and a first connecting part 2333 connected to each other. Fixing part 2331 is parallel to end cap 231 and abuts against the side of electrode terminal 232 facing away from electrode assembly 22. First main body part 2332 is disposed around electrode terminal 232. First connecting part 2333 is connected to reinforcing layer 2312. The matrix material of reinforcing layer 2312 is the same as the matrix material of fixing member 233. The strength of matrix material of reinforcing layer 2312 is stronger than the strength of matrix material of base layer 2311.

[0096] The opening 211 of the housing 21 can be one or two. If the opening 211 of the housing 21 is one, then the end cap 231 can be one; if the opening 211 of the housing 21 is two, then the end cap 231 can be two, and the two end caps 231 respectively cover the two openings 211; regardless of location, the opening 211 can be located at the top, bottom or side of the housing 21.

[0097] The base layer 2311 refers to the basic structure located at the bottom layer of the end cap 231. The base layer 2311 faces the interior of the shell 21 and can be directly connected to the shell 21. The base layer 2311 is usually made of a material with a certain mechanical strength, such as aluminum, aluminum alloy, or other weldable metal materials.

[0098] The reinforcing layer 2312 refers to the reinforcing structure located on the top layer of the end cap 231. The reinforcing layer 2312 is located away from the interior of the shell 21 and can be directly connected to structures such as the fastener 233. The reinforcing layer 2312 is typically made of a material with high mechanical strength, such as weldable metals like aluminum alloy, steel, or titanium alloy.

[0099] The base layer 2311 and the reinforcing layer 2312 are combined together to form the end cap 231. The two can be an integral composite part, for example, they can be combined together by rolling, explosive welding, brazing, sintering, etc. to form an inseparable integral structure; or, the two can be separate structures and combined together by mechanical assembly, for example, they can be assembled together by embedding, fastener connection, extrusion casting, etc.

[0100] In this embodiment, the strength of the matrix material of the reinforcing layer 2312 is greater than that of the matrix material of the base layer 2311. Here, "strength" refers to the material's ability to resist permanent deformation or fracture. The standards for measuring material strength may include, but are not limited to, tensile strength, yield strength, compressive strength, fatigue strength, etc. Different types of materials may have different strength measurement indicators, and correspondingly, different testing methods and numerical determination methods. For example, for metallic materials, strength can be experimentally tested according to the specifications in Chinese national standards (GB standards). For instance, tensile strength and yield strength can be determined according to the tensile testing guidelines in GB / T 228, compressive strength can be determined according to the compression testing guidelines in GB / T 7314, and fatigue strength can be determined according to the axial fatigue testing guidelines in GB / T 3073.

[0101] Electrode terminal 232 refers to the component in battery cell 20 used for connecting to an external circuit. Electrode terminal 232 is located on end cap 231. One end of it, facing inwards from the housing 21, can be electrically connected to the tab 22a of electrode assembly 22 inside the housing 21 via an adapter or similar structure. The other end can be electrically connected to an external device via a wire or tab. Electrode terminal 232 serves as a current conduction channel, transferring electrical energy generated inside the battery cell 20 to an external circuit, or introducing electrical energy from an external circuit into the battery cell 20 for charging. Electrode terminal 232 is typically made of a metal with good electrical conductivity, such as copper or aluminum. The surface of electrode terminal 232 can be electroplated to improve oxidation resistance and conductivity. Electrode terminal 232 can be of various shapes and sizes; for example, it can be cylindrical, rectangular, etc. The number of electrode terminals 232 can be two or more; the multiple electrode terminals 232 include at least a positive electrode terminal and a negative electrode terminal, which are used to connect the positive electrode plate and the negative electrode plate, respectively; indiscriminately, the multiple electrode terminals 232 can be disposed on the same end cover 231, or they can be disposed on different end covers 231. It is understood that the end cover 231 is usually provided with a vertically penetrating mounting hole 2313, and the electrode terminals 232 are assembled at the mounting hole 2313. The electrode terminals 232 can partially pass through the mounting hole 2313 to achieve direct or indirect connection with the electrode assembly 22 inside the housing 21.

[0102] The fixing member 233 refers to the structural component in the battery cell 20 used to connect the electrode terminal 232 and the end cap 231. The fixing member 233 is typically made of a material with high mechanical strength, such as weldable metals like aluminum alloy, steel, or titanium alloy; the fixing member 233 can be stamped. The fixing part 2331 refers to the portion that abuts against the end of the electrode terminal 232. The fixing part 2331 can define the position of the electrode terminal 232 in the thickness direction of the end cap 231 to fix the electrode terminal 232 to the end cap 231; the fixing part 2331 can be a plate-like structure arranged axially around the electrode terminal 232. The parallelism of the fixing part 2331 to the end cap 231 can be understood as the normal directions of the two being parallel. The first main body part 2332 is the connecting part between the fixing part 2331 and the first connecting part 2333. The first main body part 2332 can surround the outer periphery of the electrode terminal 232 and support and limit the electrode terminal 232 in the circumferential direction. The first connecting part 2333 refers to the part that contacts the reinforcing layer 2312 and is directly and fixedly connected to the reinforcing layer 2312. The first connecting part 2333 can be used to reliably assemble the fastener 233 onto the end cap 231. In any case, the first connecting part 2333 and the reinforcing layer 2312 can be connected and fixed by welding, bonding, riveting, snap-fitting, fastener connection, etc., where welding includes, but is not limited to, laser welding, ultrasonic welding, etc. It is understood that the fastener 233 and the reinforcing layer 2312 are designed to be of the same material to ensure that their contact surfaces have similar melting points, coefficients of thermal expansion, and other physical properties. This reduces welding defects caused by material differences during the welding process when the two are connected and fixed by welding, thereby improving the reliability and bonding strength of the welded connection between the fastener 233 and the reinforcing layer 2312.

[0103] Please refer to Figure 6 and Figure 7 The fixing part 2331 has a certain thickness along the thickness direction of the end cover 231. Increasing the strength of the base material of the fixing member 233 can at least reduce the thickness of the fixing part 2331, thereby reducing the overall height of the fixing member 233.

[0104] In the embodiments provided in this application, the end cap 231 includes a base layer 2311 and a reinforcing layer 2312 disposed on the base layer 2311. The strength of the matrix material of the reinforcing layer 2312 is stronger than that of the matrix material of the base layer 2311. By replacing part of the base layer 2311 structure with the reinforcing layer 2312, the overall thickness of the end cap 231 can be reduced while maintaining the overall strength of the end cap 231, thereby reducing the space occupied by the end cap 231. The matrix material of the fastener 233 is the same as that of the reinforcing layer 2312. By increasing the matrix of the fastener 233... The strength of the material allows for a reduction in the thickness of the fixing part 2331 while maintaining the overall strength of the fixing member 233. This reduces the overall size of the fixing member 233, thereby reducing the constraint of the fixing member 233 on the height of the electrode terminal 232. The electrode terminal 232 can be designed to be lower, thus reducing the space occupied by the electrode terminal 232. By reducing the space occupied by the end cap 231 and the electrode terminal 232 in the battery cell 20, more usable space can be provided for the electrode assembly 22, electrolyte, etc., thereby increasing the energy density of the battery cell 20.

[0105] It is understandable that designing the end cap 231 as a composite structure of the base layer 2311 and the reinforcing layer 2312 can improve the overall strength of the end cap 231 without changing its thickness.

[0106] Please refer to Figure 6 In some embodiments, the outer edge of the electrode terminal 232 facing away from the electrode assembly 22 is provided with a slot 2321, and the fixing part 2331 is at least partially provided in the slot 2321.

[0107] The slot 2321 refers to the groove provided on the surface of the electrode terminal 232. The slot 2321 can be a continuous groove provided around the outer periphery of the electrode terminal 232, or it can be multiple independent grooves provided intermittently around the outer periphery of the electrode terminal 232.

[0108] Along the radial direction of the electrode terminal 232, the fixing part 2331 is at least partially inserted into the slot 2321 to achieve a limiting engagement with the electrode terminal 232; along the axial direction of the electrode terminal 232, the fixing part 2331 does not protrude from the end face of the electrode terminal 232 to reduce the space occupied in the thickness direction of the end cover 231.

[0109] In the above embodiments, by providing a slot 2321 on the electrode terminal 232 to accommodate the fixing member 233, it is beneficial to reduce the overall height of the electrode terminal 232 and the fixing member 233, thereby further reducing the space occupied by the electrode terminal 232 and the fixing member 233.

[0110] Understandably, in some embodiments, the side of the electrode terminal 232 facing away from the electrode assembly 22 may also be a flat surface, and the fixing part 2331 directly abuts against the edge of the surface of the electrode terminal 232.

[0111] In some embodiments, the tensile strength of the matrix material of the base layer 2311 is T1, the tensile strength of the matrix material of the reinforcing layer 2312 is T2, and 1≤T2 / T1≤10.

[0112] For example, T2 / T1 can be 1, 3, 5, 8, or 10.

[0113] Tensile strength refers to the maximum stress that a material can withstand before it breaks under tension. The greater the tensile strength, the less likely the material is to break. For example, the sample to be tested can be processed into a standard specimen, and the two ends of the specimen can be fixed on the fixture of a universal testing machine. By applying an axial tensile load until the specimen breaks, the tensile strength data of the material can be obtained.

[0114] T1 refers to the maximum tensile stress that the base layer 2311 matrix material can withstand, and T2 refers to the maximum tensile stress that the reinforcing layer 2312 matrix material can withstand. The ratio of T2 / T1 represents the proportional relationship between the tensile strength of the reinforcing layer 2312 matrix material and the base layer 2311 matrix material. The magnitude of this ratio can reflect the strength difference between the matrix materials of the two layers. The larger the T2 / T1 ratio, the stronger the reinforcing layer 2312 matrix material is relative to the base layer 2311 matrix material.

[0115] In the battery cell 20, the design of the end cap 231 needs to meet the strength requirements. The strength of the end cap 231 is directly related to the material and thickness of the base layer 2311 and the reinforcing layer 2312. Under the premise that the material and thickness of the base layer 2311 remain unchanged, the stronger the base material of the reinforcing layer 2312 is relative to the base material of the base layer 2311, the more obvious the effect on improving the strength of the end cap 231, and the smaller the required thickness of the reinforcing layer 2312. The thickness of the base layer 2311 and the reinforcing layer 2312 not only affects the strength of the end cap 231, but also affects the assembly difficulty of the two. The smaller the thickness of the base layer 2311 and the reinforcing layer 2312, or the larger the thickness difference, the higher the composite difficulty.

[0116] In the above embodiments, by limiting the ratio of tensile strength between the substrate material of the base layer 2311 and the substrate material of the reinforcing layer 2312, the strength design requirements and thickness design requirements of the end cover 231 can be balanced, thereby keeping the thickness of the base layer 2311 and the reinforcing layer 2312 in the end cover 231 within a reasonable range. This can both improve the energy density of the battery cell 20 and help reduce the processing difficulty of the end cover 231.

[0117] In some embodiments, the yield strength of the matrix material of the base layer 2311 is σ1, the yield strength of the matrix material of the reinforcing layer 2312 is σ2, and 1≤σ2 / σ1≤4.

[0118] For example, σ2 / σ1 can be 1, 2, 3, or 4.

[0119] Yield strength refers to the maximum stress that a material can withstand before irreversible plastic deformation occurs. The greater the yield strength, the less likely the material is to undergo irreversible deformation. For example, the sample to be tested can be processed into a standard specimen, and the two ends of the specimen can be fixed on the fixture of a universal testing machine. By applying an axial tensile load and measuring the strain using an extensometer, the stress-strain curve can be obtained, thereby obtaining the yield strength data of the material.

[0120] σ1 refers to the critical stress at which the base layer 2311 matrix material undergoes plastic deformation, and σ2 refers to the critical stress at which the reinforcing layer 2312 matrix material undergoes plastic deformation. σ2 / σ1 represents the ratio of the yield strength between the reinforcing layer 2312 matrix material and the base layer 2311 matrix material. The magnitude of this ratio can reflect the strength difference between the matrix materials of the two layers. The larger σ2 / σ1 is, the stronger the reinforcing layer 2312 matrix material is relative to the base layer 2311 matrix material.

[0121] In the battery cell 20, the design of the end cap 231 needs to meet the strength requirements. The strength of the end cap 231 is directly related to the material and thickness of the base layer 2311 and the reinforcing layer 2312. Under the premise that the material and thickness of the base layer 2311 remain unchanged, the stronger the base material of the reinforcing layer 2312 is relative to the base material of the base layer 2311, the more obvious the effect on improving the strength of the end cap 231, and the smaller the required thickness of the reinforcing layer 2312. The thickness of the base layer 2311 and the reinforcing layer 2312 not only affects the strength of the end cap 231, but also affects the assembly difficulty of the two. The smaller the thickness of the base layer 2311 and the reinforcing layer 2312, or the larger the thickness difference, the higher the composite difficulty.

[0122] In the above embodiments, by limiting the ratio of yield strength between the substrate material of the base layer 2311 and the substrate material of the reinforcing layer 2312, the strength design requirements and thickness design requirements of the end cap 231 can be balanced, thereby keeping the thickness of the base layer 2311 and the reinforcing layer 2312 in the end cap 231 within a reasonable range. This can both improve the energy density of the battery cell 20 and help reduce the processing difficulty of the end cap 231.

[0123] Understandably, in some other embodiments, in addition to tensile strength and yield strength, indicators such as elastic modulus, compressive strength, and fatigue strength can also be used to determine the strength of the end cap 231.

[0124] In some embodiments, the thickness of the end cap 231 is H, and the thickness of the reinforcing layer 2312 is H1, where 5% ≤ (H1 / H) × 100% ≤ 40%.

[0125] For example, H1 / H can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.30, 0.35, or 0.4.

[0126] Let the thickness of the reinforcing layer 2312 be H1, and the thickness of the base layer 2311 be H2, then H = H1 + H2. The ratio H1 / H represents the proportional relationship between the thickness of the reinforcing layer 2312 and the total thickness of the end cap 231, that is, the thickness proportion of the reinforcing layer 2312 in the end cap 231. The magnitude of this ratio reflects the thickness difference between the reinforcing layer 2312 and the base layer 2311. The larger H1 / H is, the larger the proportion of the reinforcing layer 2312. Under the premise that the proportion of the reinforcing layer 2312 is not more than half, the thickness difference between the reinforcing layer 2312 and the base layer 2311 is smaller. At the same time, since different materials have different densities, the material and size design of the base layer 2311 and the reinforcing layer 2312 will also affect the weight of the end cap 231. For common metal materials, the stronger the strength, the greater the density. Therefore, the larger the proportion of the reinforcing layer 2312, the more likely it is to increase the weight of the end cap 231.

[0127] In the battery cell 20, the design of the end cap 231 must not only consider the strength requirements, but also the weight and processing difficulty of the end cap 231. The increase in the weight of the end cap 231 will lead to an increase in the weight of the battery cell 20 itself, which will cause an increase in energy consumption when it is used in electrical devices. The base layer 2311 and the reinforcing layer 2312 are made of different materials. The two can be combined together by rolling, explosive welding, brazing, sintering and other methods. For common assembly processes, the greater the difference in thickness between the base layer 2311 and the reinforcing layer 2312, the higher the difficulty of the composite process.

[0128] In the above embodiments, by limiting the thickness ratio of the reinforcing layer 2312, it is helpful to achieve the best match between the strength, weight and manufacturing process of the end cap 231. While improving the overall performance of the battery cell 20, it also helps to reduce the processing difficulty of the end cap 231.

[0129] It should be noted that the base layer 2311 and the reinforcing layer 2312 can be flat structures, or they can be provided with grooves or protrusions in local locations. The thickness in the above embodiments represents the average thickness of the base layer 2311, the reinforcing layer 2312, and the end cap 231 in the main body. For local locations where grooves or protrusions are provided, the thickness ratio of the reinforcing layer 2312 can be within or outside the above range.

[0130] In some embodiments, the base layer 2311 is an aluminum layer and the reinforcing layer 2312 is a steel layer.

[0131] In the above embodiments, the tensile strength and yield strength of steel are significantly higher than those of aluminum. Laying a steel layer on the surface of the aluminum layer can effectively improve the strength of the end cap 231, or reduce the thickness of the end cap 231 while ensuring the same strength. Aluminum and steel have stable chemical properties, and the two are not prone to chemical reaction and corrosion problems after being combined.

[0132] Please refer to Figure 6 and Figure 7 In some embodiments, the end cap 231 is provided with a mounting groove 2314, the groove opening of which is located on the side of the reinforcing layer 2312 away from the base layer 2311. The fixing member 233 is disposed in the mounting groove 2314, and the first connecting part 2333 is welded to the groove wall of the mounting groove 2314. The bottom wall of the mounting groove 2314 is also provided with a vertically penetrating mounting hole 2313, and the electrode terminal 232 is opposite to the mounting hole 2313.

[0133] Mounting groove 2314 refers to a groove provided on the surface of end cap 231. Mounting groove 2314 has a certain depth and can accommodate at least part of electrode terminal 232, fixing member 233 and insulating member 234. Mounting groove 2314 can be manufactured by stamping, machining or other methods.

[0134] As an example, the end cap 231 is provided with a fixing member 233 and an insulating member 234. The fixing part 2331 and the first main body part 2332 of the fixing member 233 are covered inside the insulating member 234. The first connecting part 2333 extends from the bottom of the outer periphery of the insulating member 234 and extends in a direction away from the electrode terminal 232. The first connecting part 2333 is provided in the mounting groove 2314 and its upper surface does not protrude from the outer surface of the end cap 231. The outer surface of the end cap 231 refers to the side of the end cap 231 that is away from the receiving space.

[0135] In the above embodiments, by forming a mounting groove 2314 on the end cover 231 to accommodate the fastener 233, the space utilization efficiency on the end cover 231 can be improved, and the flatness of the outer surface of the end cover 231 can be increased.

[0136] Please refer to Figure 3 , Figure 8 and Figure 9 , Figure 8 This is a front view of a battery cell 20 provided in some embodiments of this application. Figure 9 The image shows a side view of a battery cell 20 provided in some embodiments of this application. In some embodiments, the substrate material of the base layer 2311 is the same as the substrate material of the casing 21.

[0137] Regardless of location, the base layer 2311 and the shell 21 can be connected and fixed by means of welding, bonding, riveting, snap-fitting, fastener connection, etc., wherein welding includes but is not limited to laser welding, ultrasonic welding, etc.

[0138] In the above embodiments, the shell 21 and the base layer 2311 are designed to be made of the same material to ensure that the contact surfaces of the two have similar physical properties such as melting point and coefficient of thermal expansion. In this way, when the two are connected and fixed by welding, welding defects caused by material differences can be reduced during the welding process, thereby improving the reliability and bonding strength of the welded connection between the shell 21 and the base layer 2311.

[0139] Understandably, in some other embodiments, the end cap 231 and the housing 21 can also be assembled together by riveting, snap-fitting, fastener connection or other means. In this design, the base layer 2311 and the housing 21 are made of the same material, which can prevent chemical reaction between the end cap 231 and the housing 21 from affecting the normal use of the battery cell 20.

[0140] Please refer to Figure 5 , Figure 10 and Figure 11 , Figure 10 This is a top view of a battery cell 20 provided in some embodiments of this application. Figure 11 for Figure 5 The enlarged view of the structure shown in B shows that in some embodiments, the reinforcing layer 2312 is laid on the entire surface of the base layer 2311 away from the receiving space, and the outer edge of the base layer 2311 facing the electrode assembly 22 is welded to the end face of the housing 21.

[0141] In the thickness direction of the end cap 231, the base layer 2311 includes two opposing surfaces, and the reinforcing layer 2312 covers one side surface of the base layer 2311, forming a parallel stacked structure. The housing 21 has an opening 211, and the end face of the housing 21 refers to the surface of the housing 21 where the opening 211 is provided.

[0142] As an example, the top of the housing 21 is provided with an opening 211, the end cap 231 is placed on the top of the housing 21 and seals the opening 211, and the surface of the base layer 2311 facing the electrode assembly 22 abuts against and is welded to the end face of the housing 21.

[0143] In the above embodiments, an end cap 231 suitable for side welding connection is provided. The composite structure of the base layer 2311 and the reinforcing layer 2312 in the end cap 231 is simple and easy to process and manufacture.

[0144] In some embodiments, the outer edge of the base layer 2311 facing the electrode assembly 22 is provided with a continuous positioning groove 2315. The positioning groove 2315 is used to accommodate part of the housing 21, and the bottom wall of the positioning groove 2315 is welded to the end wall of the housing 21.

[0145] The positioning groove 2315 is a groove continuously arranged around the edge of the base layer 2311. The positioning groove 2315 has a certain depth, and its width matches the wall thickness of the housing 21. One end of the housing 21 with the opening 211 can be engaged in the positioning groove 2315. It can be understood that since the positioning groove 2315 is arranged around the edge of the base layer 2311, a protruding structure can be formed in the middle of the base layer 2311, and this protruding structure can be fitted into the opening 211 of the housing 21.

[0146] In the above embodiments, the positioning groove 2315 can provide precise positioning for the assembly of the end cap 231 and the housing 21, thereby reducing the assembly error between the end cap 231 and the housing 21. At the same time, the design of the positioning groove 2315 also allows part of the end cap 231 to be housed in the housing 21, reducing the space occupied by the end cap 231, thereby helping to reduce the overall volume of the battery cell 20 or increase the energy density of the battery cell 20.

[0147] Understandably, in some other embodiments, the side of the base layer 2311 away from the reinforcing layer 2312 may also be designed as a flat surface.

[0148] In some embodiments, the thickness of the base layer 2311 at the location where it is connected to the housing 21 is greater than or equal to 0.3 mm.

[0149] The phrase "at the location where the base layer 2311 is used to connect to the housing 21" can be understood as: the area where the base layer 2311 is used for direct contact and welding connection with the end face of the housing 21. For example, please refer to... Figure 5 The outer edge of the base layer 2311, which is used to connect the housing 21, is provided with a continuous positioning groove 2315. Along the thickness direction of the end cap 231, the positioning groove 2315 penetrates part of the base layer 2311. At the location where the positioning groove 2315 is opened, the thickness d of the base layer 2311 that is not penetrated is greater than or equal to 0.3mm.

[0150] The thickness of the base layer 2311 directly affects the reliability of the connection between the end cap 231 and the housing 21. For example, the welding process relies on high temperature to melt the material. If the thickness of the base layer 2311 in the connection area is too thin, the local high temperature during the welding process may cause the base layer 2311 to melt through. The holes generated by the melting through will affect the welding quality and reduce the sealing and bonding strength of the connection.

[0151] In the above embodiments, by reasonably limiting the thickness of the base layer 2311 in the connection area, the connection strength and reliability between the end cap 231 and the housing 21 can be improved.

[0152] Please refer to Figures 12-15 , Figure 12 This is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. Figure 13 This is a top view of a battery cell 20 provided in some embodiments of this application. Figure 14 This is a schematic diagram of the structure of the end cap 231 provided in some embodiments of this application. Figure 15 for Figure 12 The enlarged view of the structure shown in C shows that in some embodiments, the base layer 2311 has a receiving groove (not shown) on the side facing away from the electrode assembly 22, the reinforcing layer 2312 is laid in the receiving groove, and the outer peripheral surface of the base layer 2311 is welded to the inner wall of the housing 21.

[0153] The receiving groove refers to a recess on one side surface of the base layer 2311. The reinforcing layer 2312 is laid in the receiving groove and covers the bottom wall of the receiving groove. The bottom wall of the receiving groove can be designed as a flat plane, or various protrusions or grooves can be designed in local locations. The shell 21 has an internal receiving space. The inner wall of the shell 21 refers to the surface of the side wall of the shell 21 facing the receiving space.

[0154] As an example, the top of the housing 21 is provided with an opening 211, the end cap 231 is embedded in the opening 211, and the outer peripheral surface of the base layer 2311 is attached to and welded to the inner wall of the housing 21.

[0155] In the above embodiments, an end cap 231 suitable for top welding connection is provided, in which the base layer 2311 and the reinforcing layer 2312 are embedded and matched, resulting in higher structural stability.

[0156] In some embodiments, the wall thickness of the mounting groove 2314 is 0.5mm-5mm.

[0157] The wall thickness of the mounting groove 2314 refers to the dimension of the groove wall of the mounting groove 2314 in the direction perpendicular to the thickness of the end cover 231. For example, the wall thickness of the mounting groove 2314 can be 0.5mm, 1.5mm, 3mm, 4.5mm, or 5mm.

[0158] The wall thickness of the mounting groove 2314 directly affects the reliability of the connection between the end cap 231 and the housing 21. For example, the groove wall of the mounting groove 2314 can be used for welding connection with the inner wall of the housing 21. The welding process relies on high temperature to melt the material. If the wall thickness of the mounting groove 2314 is too thin, the local high temperature during the welding process may cause the groove wall of the mounting groove 2314 to melt through. The hole generated by the melting through will affect the welding quality and reduce the sealing and bonding strength of the connection. If the wall thickness of the mounting groove 2314 is too thick, it will encroach on the space of the reinforcing layer 2312 and affect the overall strength of the end cap 231.

[0159] In the above embodiments, by reasonably limiting the wall thickness of the mounting groove 2314, the connection strength and reliability between the end cap 231 and the housing 21 can be improved.

[0160] Please refer to Figure 6 In some embodiments, the battery cell 20 includes an insulating member 234, which is at least partially disposed between the electrode terminal 232 and the fixing member 233.

[0161] Insulating component 234 refers to an insulating structural component surrounding electrode terminal 232. Insulating component 234 can surround the outer periphery of electrode terminal 232 and fit tightly against electrode terminal 232, thereby physically isolating electrode terminal 232 from other metal components on end cap 231. Insulating component 234 is typically made of materials with good insulating properties, such as epoxy resin, rubber, etc. These materials also have good high-temperature resistance and chemical corrosion resistance, enabling long-term use without being corroded by electrolyte.

[0162] In the above design, by setting the insulating component 234, the electrode terminal 232 and the metal parts on the end cover 231 can be kept electrically insulated, thereby reducing the risk of electrical faults such as short circuits.

[0163] In some embodiments, the insulating member 234 covers the exterior of the fixing portion 2331 and the first main body portion 2332.

[0164] Optionally, the fastener 233 can be stamped and integrated with the insulator 234 through an embedded injection molding process.

[0165] As an example, the outer edge of the electrode terminal 232 facing away from the electrode assembly 22 is provided with a slot 2321, and the inner wall of the insulating member 234 is provided with a boss 2341 for fitting the electrode terminal 232. The boss 2341 is used to engage with the slot 2321 for holding. The fixing part 2331 and the first main body part 2332 are covered inside the insulating member 234, and the first connecting part 2333 extends from the bottom of the outer periphery of the insulating member 234 and extends in a direction away from the electrode terminal 232.

[0166] In the above embodiments, the insulating component 234 has a good insulating effect and can fit tightly with the electrode terminal 232 and the end cap 231, thereby improving the sealing performance at the electrode terminal 232.

[0167] Please refer to Figure 5 and Figure 16 , Figure 16 for Figure 5 The enlarged view of the structure shown in D shows that in some embodiments, the end cap 231 is provided with a liquid injection hole 2316, and the battery cell 20 includes a first sealing pin 235, which covers the liquid injection hole 2316. The base material of the first sealing pin 235 is the same as the base material of the reinforcing layer 2312.

[0168] The electrolyte injection hole 2316 is a through hole penetrating the end cap 231. The electrolyte injection hole 2316 is used to inject electrolyte into the internal environment of the battery cell 20 during the assembly process. The electrolyte injection hole 2316 can be of various shapes and sizes, for example, it can be a cylindrical hole, a tapered hole, or a stepped hole.

[0169] The first sealing pin 235 refers to a structural component used to seal the injection hole 2316. The first sealing pin 235 can have various shapes and sizes; for example, it can be a disc-shaped structure, with its outer contour larger than the diameter of the injection hole 2316. The first sealing pin 235 is made of a weldable material with sufficient mechanical strength, such as aluminum alloy, steel, or titanium alloy. In any case, the first sealing pin 235 and the reinforcing layer 2312 can be connected and fixed by welding, bonding, riveting, snap-fitting, fastener connection, etc., including but not limited to laser welding and ultrasonic welding. It is understood that the first sealing pin 235 and the reinforcing layer 2312 are designed to be of the same material to ensure that their contact surfaces have similar melting points, coefficients of thermal expansion, and other physical properties. This reduces welding defects caused by material differences when the two are connected and fixed by welding, thereby improving the reliability and bonding strength of the welded connection between the first sealing pin 235 and the reinforcing layer 2312.

[0170] In the above embodiments, the first sealing nail 235 and the reinforcing layer 2312 of the end cap 231 are designed to be made of the same material, which can avoid the chemical reaction that occurs after the two are assembled and corrosion problems occur. Furthermore, the two can be connected and fixed by welding, thereby having higher connection strength and good sealing performance.

[0171] Please refer to Figure 16In some embodiments, the first sealing nail 235 is welded to the reinforcing layer 2312. The first sealing nail 235 includes a second main body portion 2351, a second connecting portion 2352 and a buffer portion 2353. The second connecting portion 2352 is disposed around the second main body portion 2351. The buffer portion 2353 is connected between the second main body portion 2351 and the second connecting portion 2352. The buffer portion 2353 arches toward the base layer 2311.

[0172] The welding process relies on high temperature to melt the material. When the temperature rises, the first sealing nail 235 expands due to heat, and when the temperature drops, the first sealing nail 235 contracts. During this process, the shape and size of the first sealing nail 235 change, and large stress is easily generated at the welding point with the reinforcing layer 2312. The arched buffer part 2353 can absorb this stress through deformation, thereby reducing the risk of the first sealing nail 235 breaking or the connection failure at the welding point.

[0173] Please refer to Figure 16 In some embodiments, the injection hole 2316 is a stepped hole, which includes a first hole segment 23161 and a second hole segment 23162. The first hole segment 23161 is located on the side of the second hole segment 23162 away from the housing 21, and the diameter of the first hole segment 23161 is larger than the diameter of the second hole segment 23162. The first sealing nail 235 is a disc-shaped structure and covers the first hole segment 23161. The battery cell 20 also includes a second sealing nail 236, which is a columnar structure and is inserted into the second hole segment 23162.

[0174] In the above embodiment, the two sealing pins jointly seal the injection hole 2316, which can effectively improve the reliability of the seal and reduce the risk of leakage at the injection hole 2316.

[0175] Please refer to Figure 7 In some embodiments, the battery cell 20 further includes a lower plastic 239, which is disposed on the side of the base layer 2311 away from the reinforcing layer 2312, for achieving insulation isolation between the end cap 231 and the internal components of the housing 21.

[0176] Please refer to Figure 6 and Figure 7 In some embodiments, the battery cell 20 further includes a seal 237, which is disposed around the electrode terminal 232 and fits against the outer peripheral surface of the electrode terminal 232, and is pressed between the insulating member 234 and the end cap 231.

[0177] The seal 237 refers to the component in the battery cell 20 that serves a sealing function. The seal 237 is located at the bottom of the electrode terminal 232 near the end cap 231, and is used to seal the gap between the electrode terminal 232 and the mounting hole 2313 on the end cap 231. The seal 237 is typically made of a material with good insulation properties and resistance to chemical corrosion, such as epoxy resin, rubber, etc.

[0178] In the above embodiments, by providing a sealing element 237, the sealing performance between the electrode terminal 232 and the end cap 231 can be improved, thereby preventing electrode liquid or gas from leaking from the gap at the assembly position of the electrode terminal 232.

[0179] Please refer to Figure 7 In some embodiments, the battery cell 20 further includes a pressure relief mechanism 238, which is mounted on the end cap 231.

[0180] The pressure relief mechanism 238 is used to release the internal pressure of the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a threshold. The pressure relief mechanism 238 can be an explosion-proof valve, explosion-proof disc, air valve or safety valve, etc.

[0181] Please refer to Figure 5 , Figure 10 and Figure 11In one specific embodiment provided in this application, the battery cell 20 includes a housing 21, an electrode assembly 22, an end cap 231, electrode terminals 232, and a fixing member 233. The housing 21 has an opening 211, and the interior of the housing 21 has a receiving space. The electrode assembly 22 is disposed within the receiving space. The end cap 231 is disposed on the side of the housing 21 where the opening 211 is provided, and is used to seal the opening 211. The end cap 231 includes a base layer 2311 and a reinforcing layer 2312 stacked together, wherein the base layer 2311 faces the electrode assembly 22, and the reinforcing layer 2312 covers the entire surface of the base layer 2311 away from the electrode assembly 22. The outer edge of the surface of the base layer 2311 facing the electrode assembly 22 is also provided with a continuous positioning groove 2315, and the bottom wall of the positioning groove 2315 is tightly fitted and welded to the end face of the end cap 231. Electrode terminal 232, fixing member 233 and insulating member 234 are disposed on the outer surface of end cap 231, wherein insulating member 234 surrounds the outer periphery of electrode terminal 232, fixing member 233 includes fixing part 2331, first main body part 2332 and first connecting part 2333, fixing part 2331 abuts against the side of electrode terminal 232 facing away from electrode assembly 22, first main body part 2332 is disposed around the outer periphery of electrode terminal 232, and first connecting part 2333 is welded to reinforcing layer 2312, wherein fixing part 2331 and first main body part 2332 are covered inside insulating member 234. The end cap 231 is also provided with an injection hole 2316, which is a stepped hole and includes a first hole segment 23161 and a second hole segment 23162 that are connected. The first sealing nail 235 is a disc-shaped structure and is placed on the first hole segment 23161. The second sealing nail 236 is a columnar structure and is held in the second hole segment 23162. The base layer 2311 of the end cap 231 and the base material of the shell 21 are the same. Optionally, the base material of the base layer 2311 and the base material of the shell 21 are both aluminum. The base materials of the reinforcing layer 2312, the fastener 233 and the first sealing nail 235 of the end cap 231 are the same. Optionally, the base materials of the reinforcing layer 2312, the fastener 233 and the first sealing nail 235 are all steel.

[0182] Please refer to Figure 12 , Figure 14 and Figure 15In another specific embodiment provided in this application, the battery cell 20 includes a housing 21, an electrode assembly 22, an end cap 231, electrode terminals 232, and a fixing member 233. The housing 21 has an opening 211, and the interior of the housing 21 has a receiving space. The electrode assembly 22 is disposed within the receiving space. The end cap 231 is embedded in the opening 211 of the housing 21 and is used to seal the opening 211. The end cap 231 includes a base layer 2311 and a reinforcing layer 2312 stacked together, wherein the base layer 2311 faces the electrode assembly 22, and a receiving groove is provided on the side of the base layer 2311 away from the electrode assembly 22, and the reinforcing layer 2312 is laid in the receiving groove. The outer peripheral surface of the base layer 2311 is tightly fitted and welded to the inner wall of the housing 21. Electrode terminal 232, fixing member 233 and insulating member 234 are disposed on the outer surface of end cap 231, wherein insulating member 234 surrounds the outer periphery of electrode terminal 232, fixing member 233 includes fixing part 2331, first main body part 2332 and first connecting part 2333, fixing part 2331 abuts against the side of electrode terminal 232 facing away from electrode assembly 22, first main body part 2332 is disposed around the outer periphery of electrode terminal 232, and first connecting part 2333 is welded to reinforcing layer 2312, wherein fixing part 2331 and first main body part 2332 are covered inside insulating member 234. The end cap 231 is also provided with an injection hole 2316, which is a stepped hole and includes a first hole segment 23161 and a second hole segment 23162 that are connected. The first sealing nail 235 is a disc-shaped structure and is placed on the first hole segment 23161. The second sealing nail 236 is a columnar structure and is held in the second hole segment 23162. The base layer 2311 of the end cap 231 and the base material of the shell 21 are the same. Optionally, the base material of the base layer 2311 and the base material of the shell 21 are both aluminum. The base materials of the reinforcing layer 2312, the fastener 233 and the first sealing nail 235 of the end cap 231 are the same. Optionally, the base materials of the reinforcing layer 2312, the fastener 233 and the first sealing nail 235 are all steel.

[0183] In summary, the battery cell 20 provided in this application embodiment reduces the thickness of the end cap 231 and the height of the electrode terminal 232 by improving the structure of the end cap 231 and the fixing member 233. This optimization scheme can significantly reduce the space occupied by the end cap 231 and the electrode terminal 232, providing more usable space for the electrode assembly 22 and the electrolyte, thereby effectively increasing the energy density of the battery cell 20.

[0184] An embodiment of the second aspect of this application provides an end cap assembly 23, including an end cap 231, an electrode terminal 232, an insulating member 234, and a fixing member 233. The end cap 231 includes a base layer 2311 and a reinforcing layer 2312 stacked along the thickness direction of the end cap 231. The electrode terminal 232 is disposed on the end cap 231. The fixing member 233 includes a fixing portion 2331, a first main body portion 2332, and a first connecting portion 2333 disposed on the insulating member 234 and connected to it. The fixing portion 2331 is parallel to the end cap 231 and abuts against the side of the electrode terminal 232 facing away from the end cap 231. The first main body portion 2332 surrounds the electrode terminal 232, and the first connecting portion 2333 is connected to the reinforcing layer 2312. The base material of the reinforcing layer 2312 is the same as the base material of the fixing member 233, and the strength of the base material of the reinforcing layer 2312 is stronger than the strength of the base material of the base layer 2311.

[0185] The end cap assembly 23 provided in the above embodiments can be applied to the battery cell 20 in the first aspect.

[0186] The end cap assembly 23 provided in this application embodiment reduces the thickness of the end cap 231 and the height of the electrode terminal 232 by improving the structure of the end cap 231 and the fixing member 233. When the end cap assembly 23 is applied in the battery cell 20, since the end cap 231 and the electrode terminal 232 occupy less space, more usable space can be provided for the electrode assembly 22 and the electrolyte, thereby effectively increasing the energy density of the battery cell 20.

[0187] In some embodiments, the tensile strength of the matrix material of the base layer 2311 is T1, the tensile strength of the matrix material of the reinforcing layer 2312 is T2, and 1≤T2 / T1≤10.

[0188] For example, T2 / T1 can be 1, 3, 5, 8, or 10.

[0189] In the above embodiments, by limiting the ratio of tensile strength between the substrate material of the base layer 2311 and the substrate material of the reinforcing layer 2312, the strength design requirements and thickness design requirements of the end cover 231 can be balanced, thereby keeping the thickness of the base layer 2311 and the reinforcing layer 2312 in the end cover 231 within a reasonable range. This can both improve the energy density of the battery cell 20 and help reduce the processing difficulty of the end cover 231.

[0190] In some embodiments, the yield strength of the matrix material of the base layer 2311 is σ1, the yield strength of the matrix material of the reinforcing layer 2312 is σ2, and 1≤σ2 / σ1≤4.

[0191] For example, σ2 / σ1 can be 1, 2, 3, or 4.

[0192] In the above embodiments, by limiting the ratio of yield strength between the substrate material of the base layer 2311 and the substrate material of the reinforcing layer 2312, the strength design requirements and thickness design requirements of the end cap 231 can be balanced, thereby keeping the thickness of the base layer 2311 and the reinforcing layer 2312 in the end cap 231 within a reasonable range. This can both improve the energy density of the battery cell 20 and help reduce the processing difficulty of the end cap 231.

[0193] Understandably, in some other embodiments, in addition to tensile strength and yield strength, indicators such as elastic modulus, compressive strength, and fatigue strength can also be used to determine the strength of the end cap 231.

[0194] In some embodiments, the thickness of the end cap 231 is H, and the thickness of the reinforcing layer 2312 is H1, where 5% ≤ (H1 / H) × 100% ≤ 40%.

[0195] For example, H1 / H can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.30, 0.35, or 0.4.

[0196] In the above embodiments, by limiting the thickness ratio of the reinforcing layer 2312, it is helpful to achieve the best match between the strength, weight and manufacturing process of the end cap 231. While improving the overall performance of the battery cell 20, it also helps to reduce the processing difficulty of the end cap 231.

[0197] It should be noted that the base layer 2311 and the reinforcing layer 2312 can be flat structures, or they can be provided with grooves or protrusions in local locations. The thickness in the above embodiments represents the average thickness of the base layer 2311, the reinforcing layer 2312, and the end cap 231 in the main body. For local locations where grooves or protrusions are provided, the thickness ratio of the reinforcing layer 2312 can be within or outside the above range.

[0198] In some embodiments, the base layer 2311 is an aluminum layer and the reinforcing layer 2312 is a steel layer.

[0199] In the above embodiments, the tensile strength and yield strength of steel are significantly higher than those of aluminum. Laying a steel layer on the surface of the aluminum layer can effectively improve the strength of the end cap 231, or reduce the thickness of the end cap 231 while ensuring the same strength. Aluminum and steel have stable chemical properties, and the two are not prone to chemical reaction and corrosion problems after being combined.

[0200] An embodiment of the third aspect of this application provides a battery device 100, including the battery cell 20 of the first aspect.

[0201] The battery device 100 provided in this application improves the energy density and overall performance of the battery device 100 by adopting the battery cell 20 in the first aspect.

[0202] An embodiment of the fourth aspect of this application provides an electrical device, including a battery cell 20 as in the first aspect or a battery device 100 as in the third aspect, wherein the battery cell 20 or the battery device 100 is used to store or provide electrical energy.

[0203] The electrical equipment provided in this application improves the battery life and usability by using the battery cell 20 in the first aspect or the battery device 100 in the third aspect.

[0204] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, include: A housing having an opening, the interior of which has a receiving space; An electrode assembly is disposed within the accommodating space; An end cap that covers the opening, the end cap comprising a base layer and a reinforcing layer stacked along the thickness direction of the end cap, the reinforcing layer being disposed on the side of the base layer facing away from the electrode assembly; Electrode terminals are disposed on the end cap and electrically connected to the electrode assembly; The fastener includes a fastening part, a first main body part, and a first connecting part connected to each other. The fastening part is parallel to the end cap and abuts against the side of the electrode terminal facing away from the electrode assembly. The first main body part is disposed around the electrode terminal, and the first connecting part is connected to the reinforcing layer. The base material of the reinforcing layer is the same as the base material of the fastener, and the strength of the base material of the reinforcing layer is greater than that of the base material of the base layer.

2. The battery cell of claim 1, wherein, The outer edge of the electrode terminal facing away from the electrode assembly is provided with a slot, and the fixing part is at least partially provided in the slot.

3. The battery cell according to claim 1 or 2, wherein The tensile strength of the matrix material of the base layer is T1, the tensile strength of the matrix material of the reinforcing layer is T2, and 1≤T2 / T1≤10; and / or, the yield strength of the matrix material of the base layer is σ1, and the yield strength of the matrix material of the reinforcing layer is σ2, and 1≤σ2 / σ1≤4.

4. The battery cell of any one of claims 1-3, wherein, The thickness of the end cap is H, and the thickness of the reinforcing layer is H1, where 5% ≤ (H1 / H) × 100% ≤ 40%.

5. The battery cell of any one of claims 1-4, wherein, The base layer is an aluminum layer, and the reinforcing layer is a steel layer.

6. The battery cell of any one of claims 1-5, wherein, The base material of the base layer is the same as the base material of the shell.

7. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. The reinforcing layer is laid on the entire surface of the base layer facing away from the electrode assembly, and the outer edge of the base layer facing the electrode assembly is welded to the end face of the housing.

8. The battery cell of claim 7, wherein the cathode comprises a lithium metal oxide. The outer edge of the base layer facing the electrode assembly has a continuous positioning groove, which is used to accommodate part of the housing. The bottom wall of the positioning groove is welded to the end face of the housing.

9. The battery cell according to claim 7 or 8, wherein The thickness of the base layer at the location where it is connected to the housing is greater than or equal to 0.3 mm.

10. The battery cell of claim 6, wherein, The base layer has a receiving groove on the side facing away from the electrode assembly, the reinforcing layer is laid in the receiving groove, and the outer peripheral surface of the base layer is welded to the inner wall of the housing.

11. The battery cell of claim 10, wherein the cathode comprises a lithium metal oxide. The wall thickness of the receiving groove is 0.5mm-5mm.

12. The battery cell of any one of claims 1-11, wherein, The battery cell includes an insulating component, which is at least partially disposed between the electrode terminal and the fixing component.

13. The battery cell as described in claim 12, characterized in that, The insulating component covers the exterior of the fixing portion and the first main body portion.

14. The battery cell of any one of claims 1-13, wherein, The end cap is provided with a liquid injection hole, and the battery cell includes a first sealing pin, which covers the liquid injection hole. The base material of the first sealing pin is the same as the base material of the reinforcing layer.

15. An end cap assembly characterized by, include: An end cap, comprising a base layer and a reinforcing layer stacked along the thickness direction of the end cap; Electrode terminals are disposed on the end cap; The fastener includes a fastening part, a first main body part, and a first connecting part connected to each other. The fastening part is parallel to the end cap and abuts against the side of the electrode terminal facing away from the end cap. The first main body part is disposed around the electrode terminal. The first connecting part is connected to the reinforcing layer. The base material of the reinforcing layer is the same as the base material of the fastener, and the strength of the base material of the reinforcing layer is greater than that of the base material of the base layer.

16. The end cap assembly of claim 15, wherein, The tensile strength of the matrix material of the base layer is T1, the tensile strength of the matrix material of the reinforcing layer is T2, and 1≤T2 / T1≤10; and / or, the yield strength of the matrix material of the base layer is σ1, and the yield strength of the matrix material of the reinforcing layer is σ2, and 1≤σ2 / σ1≤4.

17. An end cap assembly as claimed in claim 15 or 16, wherein, The thickness of the end cap is H, and the thickness of the reinforcing layer is H1, where 5% ≤ (H1 / H) × 100% ≤ 40%.

18. The end cap assembly of any one of claims 15-17, wherein, The base layer is an aluminum layer, and the reinforcing layer is a steel layer.

19. A battery device characterized by comprising: Includes the battery cell as described in any one of claims 1-14.

20. An electrical device, comprising: Includes a battery cell as described in any one of claims 1-14 or a battery device as described in claim 19, wherein the battery cell or the battery device is used to store or provide electrical energy.

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