Battery cells, batteries and electrical devices

Abstract

This application provides a battery cell, a battery, and an electrical device. The battery cell includes a housing, an electrode assembly, a first electrode terminal, and a cover. The housing includes an integrally formed cylindrical body and a cover, with the cylindrical body having an opening at one end opposite to the cover. The electrode assembly is housed within the housing and includes a first tab. The first electrode terminal is disposed on the cover and used for electrical connection with the first tab. The cover is connected to the cylindrical body and closes the opening. Installing the first electrode terminal onto the cover increases the distance between the connection point of the cylindrical body and the cover and the first electrode terminal, thereby reducing the impact on the connection point of the cylindrical body and the cover when the battery cell is subjected to external impact, reducing the risk of connection failure between the cover and the housing, reducing electrolyte leakage, and improving safety.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to two applications filed on August 23, 2021, entitled “Battery cell and manufacturing method and system thereof, battery and electrical device thereof”, international application number PCT / CN2021 / 114156, and two applications filed on August 23, 2021, entitled “Battery cell and manufacturing method and system thereof, battery and electrical device thereof”, international application number PCT / CN2021 / 114155, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery, and an electrical device. Background Technology

[0004] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and rechargeable alkaline zinc-manganese battery cells, among others.

[0005] Improving the safety of individual battery cells is a research direction in battery technology. Summary of the Invention

[0006] This application provides a battery cell, a battery, and an electrical device that can improve the safety of the battery cell.

[0007] In a first aspect, embodiments of this application provide a battery cell, which includes a housing, an electrode assembly, a first electrode terminal, and a cover plate. The housing includes an integrally formed cylindrical body and a cover, the cylindrical body having an opening at one end opposite to the cover. The electrode assembly is housed within the housing and includes a first electrode tab. The first electrode terminal is disposed on the cover and used for electrical connection with the first electrode tab. The cover plate is connected to the cylindrical body and covers the opening.

[0008] In the above technical solution, by installing the first electrode terminal onto the cover and covering the opening of the cylinder, the distance between the connection between the cylinder and the cover and the first electrode terminal can be increased, thereby reducing the impact on the connection between the cylinder and the cover when the battery cell is subjected to external impact, reducing the risk of connection failure between the cover and the shell, reducing electrolyte leakage, and improving safety.

[0009] In some embodiments, the cover plate is welded to the cylinder.

[0010] In the above technical solution, welding can not only connect the cover plate and the cylinder, but also improve the sealing performance at the connection between the cover plate and the cylinder. Installing the first electrode terminal on the cover plate can increase the distance between the weld joint of the cylinder and the cover plate and the first electrode terminal, thereby reducing the impact on the weld joint of the cover plate and the cylinder when the first electrode terminal is subjected to external force, thus reducing the risk of cracking at the weld joint of the cover plate and the cylinder and improving the sealing performance.

[0011] In some embodiments, the cover plate is sealed to the cylinder by a sealing element.

[0012] In the above technical solution, the sealing performance of the battery cell can be improved by setting a seal between the cover plate and the cylinder.

[0013] In some embodiments, the first electrode terminal is used to connect to the first busbar of the battery. The first electrode terminal serves as the output electrode of a single battery cell and can be connected to the first busbar to facilitate electrical connection between battery cells.

[0014] When a battery cell is subjected to external impact, the first busbar component may pull on the first electrode terminal. The above technical solution places the first electrode terminal on the cover away from the cover plate to increase the distance between the connection between the cylinder and the cover plate and the first electrode terminal. This reduces the impact on the connection between the cylinder and the cover plate when the battery cell is subjected to external impact, reduces the risk of connection failure between the cover plate and the shell, reduces electrolyte leakage, and improves safety.

[0015] In some embodiments, the electrode assembly further includes a second tab, the polarity of which is opposite to that of the first tab. The battery cell also includes a second electrode terminal electrically connected to the second tab, the second electrode terminal being used for connection to a second busbar component of the battery.

[0016] In the above technical solution, the first electrode terminal and the second electrode terminal can serve as the two output electrodes of the battery cell to realize the electrical connection between the battery cell and the external circuit.

[0017] In some embodiments, a second electrode terminal is disposed on the cover.

[0018] In the above technical solution, the first electrode terminal and the second electrode terminal are located at the same end of the battery cell. This allows the first and second busbar components to be assembled onto the same side of the battery cell, simplifying the assembly process and improving the efficiency of assembling multiple battery cells into a group. Positioning the second electrode terminal on the cover away from the cover plate increases the distance between the connection between the casing and the cover plate and the second electrode terminal. This reduces the impact on the connection between the casing and the cover plate when the battery cell is subjected to external impact, lowers the risk of connection failure between the cover plate and the casing, reduces electrolyte leakage, and improves safety.

[0019] In some embodiments, both the first electrode terminal and the second electrode terminal protrude from the outer surface of the cover to reduce the risk of the cover interfering with the busbar component and to simplify the connection process between the busbar component and the electrode terminals.

[0020] In some embodiments, both the first electrode terminal and the second electrode terminal are insulated from the cover.

[0021] In the above technical solution, the casing is not electrified, thereby reducing the risk of leakage and improving safety.

[0022] In some embodiments, the base material of the housing is aluminum.

[0023] In the above technical solution, the aluminum casing has a lighter weight, which can increase the energy density of the battery cell. Since the casing is not charged, the aluminum casing is less susceptible to corrosion by the electrolyte.

[0024] In some embodiments, the electrode assembly further includes a body portion. Both the first tab and the second tab extend from the end of the body portion facing the cover to reduce the distance between the first tab and the first electrode terminal, and the distance between the second tab and the second electrode terminal.

[0025] In some embodiments, the electrode assembly further includes a second tab with a polarity opposite to that of the first tab. A cover is electrically connected to the second tab and is used for connection to a second busbar of the battery.

[0026] In the above technical solution, by using the cover and the first electrode terminal as the two output electrodes of the battery cell, the structure of the battery cell can be simplified while ensuring its current carrying capacity. The first electrode terminal and the cover are located at the same end of the battery cell, allowing the first and second busbar components to be assembled on the same side of the battery cell. This simplifies the assembly process and improves the efficiency of assembling multiple battery cells into a group. Connecting the second busbar component to the cover increases the distance between the connection between the cover and the casing and the connection between the second busbar component and the cover. This reduces the impact on the connection between the casing and the cover when the battery cell is subjected to external impact, lowers the risk of connection failure between the cover and the casing, reduces electrolyte leakage, and improves safety.

[0027] In some embodiments, a first tab is located at the end of the electrode assembly facing the cover, and a second tab is located at the end of the electrode assembly facing the cover. The cover is electrically connected to the second tab via a cylindrical body.

[0028] In the above technical solution, placing the first and second tabs at opposite ends of the electrode assembly increases the distance between them, reduces the risk of continuity between them, and improves safety. Connecting the cover to the second tab via the cylindrical body eliminates the need for a separate component connecting the cover and the second tab. Since the cover and cylindrical body are an integral structure, the resistance at their connection point is low, thereby improving current carrying capacity.

[0029] In some embodiments, the second electrode is a negative electrode, and the base material of the housing is steel.

[0030] The casing is electrically connected to the negative electrode tab, meaning the casing is in a low potential state. In the above technical solution, the steel casing is less susceptible to corrosion by the electrolyte in a low potential state.

[0031] In some embodiments, the cover includes a body portion and a bent portion, the bent portion being integrally connected to the cylinder and the body portion.

[0032] In the above technical solution, the bending part can release stress during the forming process of the shell, reduce stress concentration, and reduce the risk of shell breakage.

[0033] In some embodiments, the thickness of the body portion is greater than the wall thickness of the cylinder.

[0034] In the above technical solution, the thicker body portion can better support components such as the first electrode terminal; when the first electrode terminal is subjected to external force, the thicker body portion deforms less. The cylindrical body mainly isolates the electrode assembly from the outside environment, and it can have a relatively small thickness, thereby reducing the overall weight of the battery cell and increasing the energy density.

[0035] In some embodiments, the cover includes a receiving recess that is recessed from the outer surface of the body portion in a direction facing the electrode assembly. The bottom wall of the receiving recess is provided with a first electrode lead-out hole, and a first electrode terminal is mounted in the first electrode lead-out hole.

[0036] In the above technical solution, by providing a receiving recess, the size of the outer surface of the protruding body of the first electrode terminal can be reduced, thereby reducing the maximum size of the battery cell and increasing the energy density of the battery cell.

[0037] In some embodiments, the thickness D1 of the body and the wall thickness D2 of the cylinder satisfy the following: 0.1 mm ≤ D1 - D2 ≤ 2 mm.

[0038] If D1-D2 is too small, the thickness of the main body will be too small or the thickness of the cylinder will be too large. Insufficient main body thickness will result in insufficient strength, while excessive cylinder thickness will lead to excessive weight, affecting energy density. If D1-D2 is too large, the difference in stretching amount between the main body and the cylinder during the shell stretching process will be too great, making the cylinder prone to breakage during stretching. The above technical solution limits the value of D1-D2 to 0.1mm-2mm, ensuring the shell strength meets requirements and reducing the energy density loss of individual battery cells.

[0039] In some embodiments, the first electrode terminal includes a first recess and a first connecting portion located at the bottom of the first recess. The first connecting portion is used to achieve an electrical connection with the first electrode tab via a first soldering portion.

[0040] In the above technical solution, by creating a first recess on the first electrode terminal to reduce the thickness of the first connecting portion, the welding power required for welding is reduced, heat generation is decreased, the risk of other components being burned is reduced, and safety is improved. The first welding portion can reduce the resistance between the first electrode terminal and the first tab, thereby improving the current carrying capacity.

[0041] In some embodiments, the first connecting portion is welded to the first electrode tab to form a first weld portion.

[0042] The above technical solution can shorten the conductive path between the first electrode terminal and the first tab, reduce resistance, and improve the energy density and overcurrent capacity of the battery cell.

[0043] In some embodiments, the battery cell further includes a current collector connected to a first tab. A first connection portion is welded to the current collector to form a first weld portion.

[0044] In the above technical solution, by setting a current collector, the difference in current path between the first electrode terminal and the first electrode at different positions of the first electrode tab can be reduced, thereby improving the uniformity of current density of the first electrode plate of the electrode assembly, reducing internal resistance, and improving overcurrent capability.

[0045] In some embodiments, the first electrode terminal includes a terminal body and a sealing plate. The terminal body includes a first recess and a first connecting portion, the first connecting portion being located on the side of the first recess facing the electrode assembly. The sealing plate is connected to the terminal body and closes the opening of the first recess.

[0046] In the above technical solution, the sealing plate can protect the first connection part from the outside, reduce external impurities entering the first recess, reduce the risk of the first connection part being damaged by external impurities, and improve the sealing performance of the battery cell.

[0047] In some embodiments, at least a portion of the sealing plate is accommodated in the first recess.

[0048] In the above technical solution, the first recess can provide a space for the sealing plate, thereby reducing the size of the sealing plate protruding from the terminal body, reducing the space occupied by the first electrode terminal, and increasing the energy density of the battery cell.

[0049] In some embodiments, the sealing plate protrudes from the surface of the terminal body away from the electrode assembly.

[0050] In the above technical solution, at least a portion of the sealing plate protrudes from the surface of the terminal body away from the electrode assembly, so as to reduce the risk of the terminal body interfering with the fit between the sealing plate and the first busbar component and reduce the risk of poor soldering.

[0051] In some embodiments, a gap is provided between the sealing plate and the first connecting portion.

[0052] The surface of the first welded part is uneven. If the sealing plate presses against the first welded part, it will cause the sealing plate to wobble during assembly, affecting the sealing effect. The above technical solution provides a gap between the sealing plate and the first connecting part to avoid direct contact between the sealing plate and the first welded part, thereby reducing the wobble of the sealing plate during assembly and ensuring the sealing effect.

[0053] In some embodiments, the first connection portion is provided with a through hole for injecting electrolyte.

[0054] In the above technical solution, by opening a through hole for injecting electrolyte on the first connection part of the first electrode terminal, the deformation of the shell during the electrolyte injection process can be reduced, the structure of the battery cell can be simplified, and the influence of the through hole on the shell strength can be reduced.

[0055] In some embodiments, the electrode assembly further includes a second tab, the polarity of which is opposite to that of the first tab. The battery cell also includes a second electrode terminal disposed on the cover, the second electrode terminal including a second recess and a second connecting portion located at the bottom of the second recess. The second connecting portion is used to achieve an electrical connection with the second tab via a second soldering portion.

[0056] In the above technical solution, by creating a second recess on the second electrode terminal, the thickness of the second connection portion is reduced, thereby reducing the welding power required for welding, reducing heat generation, lowering the risk of other components being burned, and improving safety. The second welding portion can reduce the resistance between the second electrode terminal and the second tab, improving the current carrying capacity.

[0057] Secondly, embodiments of this application provide a battery comprising multiple battery cells provided in any of the embodiments of the first aspect.

[0058] Thirdly, embodiments of this application provide an electrical device including a battery as described in the second aspect, the battery being used to provide electrical energy. Attached Figure Description

[0059] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0060] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0061] Figure 2 Explosion diagrams of batteries provided for some embodiments of this application;

[0062] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0063] Figure 4 A partial cross-sectional schematic diagram of a battery provided for some embodiments of this application;

[0064] Figure 5 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application;

[0065] Figure 6 for Figure 4 The image shows an enlarged view of the battery at box A.

[0066] Figure 7 for Figure 4 An enlarged view of the battery shown in box B;

[0067] Figure 8 This is a partial cross-sectional schematic diagram of the casing of a battery cell provided in some embodiments of this application;

[0068] Figure 9 for Figure 6 Enlarged view of point C in the circle;

[0069] Figure 10 A cross-sectional schematic diagram of a first electrode terminal provided for some embodiments of this application;

[0070] Figure 11 Partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application;

[0071] Figure 12 Cross-sectional schematic diagrams of a battery cell provided for other embodiments of this application;

[0072] Figure 13 for Figure 12 Enlarged view at box D;

[0073] Figure 14 This is a schematic diagram of the battery structure provided in some other embodiments of this application;

[0074] Figure 15 A top view schematic diagram of a battery cell provided for other embodiments of this application;

[0075] Figure 16 for Figure 15 A cross-sectional view of the EE along the line.

[0076] The accompanying drawings are not drawn to scale. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0078] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0079] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0080] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0081] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0082] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0083] In this application, "multiple" means two or more (including two).

[0084] In this application, the term "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.

[0085] In this application, the battery cell may include lithium-ion secondary battery cell, lithium-ion primary battery cell, lithium-sulfur battery cell, sodium lithium-ion battery cell, sodium-ion battery cell, or magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto.

[0086] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0087] A battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode components. The positive electrode includes a positive current collector and a positive active material layer, with the active material layer coated on the surface of the current collector. The current collector includes a positive current-collecting section and a positive electrode tab; the current-collecting section is coated with the positive active material layer, while the positive electrode tab is not. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer, with the active material layer coated on the surface of the current collector. The current collector includes a negative current-collecting section and a negative electrode tab; the current-collecting section is coated with the negative active material layer, while the negative electrode tab is not. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes the negative electrode active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc.

[0088] The battery cell also includes a housing and a cover. The housing has an opening, and the cover is used to close the opening of the housing to enclose a space for accommodating the electrode assembly and electrolyte. During assembly, the electrode assembly can be installed into the housing through the opening, and then the cover and housing are connected to seal the opening of the housing.

[0089] In order to extract electrical energy from the electrode assembly, the battery cell is usually also provided with electrode terminals, which are used to electrically connect the electrode assembly to an external circuit to realize the charging and discharging of the electrode assembly.

[0090] In batteries, electrode terminals need to be connected to external components (such as busbars, detection harnesses, etc.). When a battery cell is subjected to external impact, the external component will pull on the electrode terminals. In related technologies, electrode terminals are usually mounted on a cover plate. Due to the size limitation of the cover plate, the distance between the electrode terminals and the connection between the cover plate and the housing (e.g., the weld) is small. When the electrode terminals are pulled by external components, the electrode terminals will exert a force on the cover plate. This force is transmitted to the connection between the cover plate and the housing, which may cause the connection between the cover plate and the housing to fail, leading to the risk of electrolyte leakage and creating a safety hazard.

[0091] In view of this, the present application provides a technical solution that increases the distance between the connection between the cover plate and the housing and the electrode terminals by installing the electrode terminals to the end of the housing away from the cover plate. This reduces the impact on the connection between the cover plate and the housing when the battery cell is subjected to external impact, thereby reducing the risk of connection failure between the cover plate and the housing and improving safety.

[0092] The technical solutions described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0093] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0094] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0095] Figure 1 The diagram shows the structural features of a vehicle as provided in some embodiments of this application. Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0096] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0097] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0098] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, battery 2 includes a housing 5 and battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0099] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0100] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0101] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0102] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0103] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0104] In some embodiments, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0105] Multiple battery cells 7 in battery module 6 can be electrically connected through busbars 8 to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, and each busbar 8 is used to electrically connect at least two battery cells.

[0106] Figure 4A partial cross-sectional schematic diagram of a battery provided for some embodiments of this application; Figure 5 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application; Figure 6 for Figure 4 The image shows an enlarged view of the battery at box A. Figure 7 for Figure 4 The image shows an enlarged view of the battery at box B.

[0107] like Figures 4 to 7 As shown, in some embodiments of this application, the battery cell 7 includes an electrode assembly 10, a housing 20, a first electrode terminal 30, and a cover plate 40. The housing 20 includes an integrally formed cylindrical body 21 and a cover 22, with the cylindrical body 21 having an opening 211 at one end opposite to the cover 22. The electrode assembly 10 is housed within the housing 20 and includes a first electrode tab 11. The first electrode terminal 30 is disposed on the cover 22 and is used for electrical connection with the first electrode tab 11. The cover plate 40 is connected to the cylindrical body 21 and covers the opening 211.

[0108] The electrode assembly 10 includes a first electrode and a second electrode with opposite polarities. One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. Exemplarily, the electrode assembly 10 generates electrical energy through oxidation and reduction reactions during the insertion / extraction of ions in the positive and negative electrode plates. Optionally, the electrode assembly 10 further includes a separator for insulating and isolating the first electrode and the second electrode.

[0109] In some examples, the first electrode, the second electrode, and the spacer are all strip structures, wound together around a central axis to form a wound structure. The wound structure can be cylindrical, flat, or other shapes. In other examples, the electrode assembly 10 can also be a stacked structure formed by arranging the first electrode, the spacer, and the second electrode in layers.

[0110] The first tab 11 can be the portion of the first electrode sheet that is not coated with the active material layer. The first tab 11 can be a positive tab or a negative tab. Correspondingly, the first electrode terminal 30 can be a positive terminal or a negative terminal.

[0111] The housing 20 is a hollow structure, forming an interior space for accommodating the electrode assembly 10. The housing 20 can be of various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. The shape of the housing 20 can be determined based on the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is cylindrical, a cylindrical housing can be used; if the electrode assembly 10 is cuboid, a cuboid housing can be used.

[0112] The shell 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0113] The casing 20 can be positively charged, negatively charged, or uncharged.

[0114] The cylindrical body 21 is arranged around the outer periphery of the electrode assembly 10. The cylindrical body 21 can be a square tube, a cylindrical tube, or other cylindrical structures, such as a hexagonal tube.

[0115] The cover 22 is connected to one end of the cylinder 21 away from the opening 211. The shape of the cover 22 is adapted to the shape of the cylinder 21. For example, if the cylinder 21 is a square cylinder, the cover 22 can be a square structure; for example, if the cylinder 21 is a round cylinder, the cover 22 can be a round structure.

[0116] The first electrode terminal 30 can be directly connected to the first electrode tab 11 to achieve an electrical connection between the first electrode terminal 30 and the first electrode tab 11. Exemplarily, the first electrode terminal 30 can be connected to the first electrode tab 11 by adhesive bonding, abutment, snap-fitting, welding, or other methods.

[0117] Alternatively, the first electrode terminal 30 can also be indirectly connected to the first tab 11 via other conductive components to achieve an electrical connection between the first electrode terminal 30 and the first tab 11. For example, a conductive component can be simultaneously connected to both the first tab 11 and the first electrode terminal 30 to achieve an electrical connection between the first electrode terminal 30 and the first tab 11.

[0118] The first electrode terminal 30 can serve as an output electrode of the battery cell 7, which can electrically connect the battery cell 7 to an external circuit to achieve charging and discharging of the battery cell 7. Optionally, the first electrode terminal 30 is used to connect to a busbar component to achieve electrical connection between the battery cells 7.

[0119] The first electrode terminal 30 can be insulatedly disposed on the housing 20 or electrically connected to the housing 20. This application embodiment does not limit this, as long as the positive electrode and the negative electrode are prevented from conducting.

[0120] The shape of the cover plate 40 can be adapted to the shape of the cylinder 21 to fit the cylinder 21. For example, if the cylinder 21 is a square cylinder, the cover plate 40 can be a square structure; for example, if the cylinder 21 is a round cylinder, the cover plate 40 can be a round structure.

[0121] The cover plate 40 and the housing 20 can be two separate components, which can be connected together by welding, riveting, bonding, snap-fitting or other means. The connection between the cylinder 21 and the cover plate 40 can refer to the area of ​​the cylinder 21 and the cover plate 40 used to achieve a fixed connection between the two.

[0122] In this embodiment of the application, by installing the first electrode terminal 30 onto the cover 22 and covering the opening 211 of the cylinder 21 with the cover plate 40, the distance between the connection between the cylinder 21 and the cover plate 40 and the first electrode terminal 30 can be increased. This reduces the impact on the connection between the cylinder 21 and the cover plate 40 when the battery cell 7 is subjected to external impact, reduces the risk of connection failure between the cover plate 40 and the housing 20, reduces electrolyte leakage, and improves safety.

[0123] In this embodiment, the cover 22 and the cylinder 21 are integrally formed, which eliminates the need for the connection process between the cover 22 and the cylinder 21.

[0124] In some embodiments, the housing 20 may be formed by a stretching process.

[0125] In some embodiments, the cover plate 40 is welded to the cylinder 21. Exemplarily, the connection between the cover plate 40 and the cylinder 21 may be a weld mark formed by welding the cover plate 40 and the cylinder 21.

[0126] Welding not only connects the cover plate 40 to the cylinder 21, but also improves the sealing performance at the connection point. Installing the first electrode terminal 30 onto the cover 22 increases the distance between the weld point of the cover plate 40 and the cylinder 21 and the first electrode terminal 30. This reduces the impact on the weld point of the cover plate 40 and the cylinder 21 when the first electrode terminal 30 is subjected to external force, thereby lowering the risk of cracking at the weld point and improving sealing performance.

[0127] In some embodiments, the cover plate 40 is connected to the cylinder 21 by laser welding.

[0128] In some embodiments, the first electrode terminal 30 is used to connect to the first busbar component 81 of the battery.

[0129] In the battery, multiple battery cells 7 are electrically connected through multiple busbars. For example, the two output electrodes of the battery cell 7 are electrically connected to two busbars respectively; the busbar for electrically connecting to the first electrode terminal 30 of the battery cell 7 may be referred to as the first busbar 81 corresponding to the battery cell 7.

[0130] The first busbar component 81 can be connected to the first electrode terminal 30 by welding, bonding, riveting or other means to realize the electrical connection between the first busbar component 81 and the first electrode terminal 30.

[0131] For example, the first bus component 81 can connect the first electrode terminal 30 of one battery cell 7 to the output electrode of another battery cell 7 to connect the two battery cells 7 in series or in parallel.

[0132] The first electrode terminal 30 serves as the output electrode of the battery cell 7 and can be connected to the first busbar component 81 to facilitate electrical connection between the battery cells 7.

[0133] When the battery cell 7 is subjected to external impact, the first busbar component 81 may pull on the first electrode terminal 30. In this embodiment, the first electrode terminal 30 is disposed on the cover 22 away from the cover plate 40 to increase the distance between the connection between the cylinder 21 and the cover plate 40 and the first electrode terminal 30. This reduces the impact on the connection between the cylinder 21 and the cover plate 40 when the battery cell 7 is subjected to external impact, reduces the risk of connection failure between the cover plate 40 and the housing 20, reduces electrolyte leakage, and improves safety.

[0134] In some embodiments, the electrode assembly 10 further includes a second tab 12, the polarity of which is opposite to that of the first tab 11. A cover 22 is electrically connected to the second tab 12 and is used to connect to a second busbar 82 of the battery.

[0135] The first tab 11 is the portion of the first electrode sheet that is not coated with an active material layer, and the second tab 12 is the portion of the second electrode sheet that is not coated with an active material layer.

[0136] Exemplarily, the electrode assembly 10 further includes a body portion 13, with a first tab 11 and a second tab 12 protruding from the body portion 13. The body portion 13 includes a portion of the first electrode coated with an active material layer and a portion of the second electrode coated with an active material layer. The first tab 11 and the second tab 12 are used to draw current from the body portion 13.

[0137] The first tab 11 and the second tab 12 can extend from the same side of the main body 13, or they can extend from opposite sides respectively.

[0138] The second tab 12 can be directly electrically connected to the cover 22, or it can be indirectly electrically connected to the cover 22 through one or more conductive structures. For example, the second tab 12 can be electrically connected to the cover 22 through the cylinder 21; or the second tab 12 can also be electrically connected to the cover 22 through the cover plate 40 and the cylinder 21.

[0139] The first electrode terminal 30 is insulated from the cover 22. The first electrode terminal 30 and the cover 22 can have different polarities and can serve as different output electrodes.

[0140] When the second tab 12 is the negative tab and the first tab 11 is the positive tab, the cover 22 is the negative output terminal of the battery cell 7, and the first electrode terminal 30 is the positive output terminal of the battery cell 7.

[0141] The busbar component used for electrical connection with the cover 22 of the battery cell 7 can be referred to as the second busbar component 82 corresponding to the battery cell 7. The second busbar component 82 can be connected to the cover 22 by welding, bonding or other means to realize the electrical connection between the second busbar component 82 and the cover 22.

[0142] For example, the first busbar 81 connects the first electrode terminal 30 of one battery cell 7 to the cover 22 of another battery cell 7, while the second busbar 82 connects the cover 22 of the one battery cell 7 to the first electrode terminal 30 of yet another battery cell 7. In this way, the first busbar 81 and the second busbar 82 connect the three battery cells 7 in series.

[0143] In this embodiment, by using the cover 22 and the first electrode terminal 30 as the two output electrodes of the battery cell 7, the structure of the battery cell 7 can be simplified while ensuring the current carrying capacity of the battery cell 7. The first electrode terminal 30 and the cover 22 are located at the same end of the battery cell 7, so that the first busbar component 81 and the second busbar component 82 can be assembled on the same side of the battery cell 7, which simplifies the assembly process and improves the efficiency of assembling multiple battery cells 7 into a group.

[0144] When the battery cell 7 is subjected to external impact, the second busbar component 82 may pull on the cover 22. Connecting the second busbar component 82 to the cover 22 can increase the distance between the connection between the cover plate 40 and the cylinder 21 and the connection between the second busbar component 82 and the cover 22. This reduces the impact on the connection between the cylinder 21 and the cover plate 40 when the battery cell 7 is subjected to external impact, reduces the risk of connection failure between the cover plate 40 and the housing 20, reduces electrolyte leakage, and improves safety.

[0145] In some embodiments, a first tab 11 is disposed at the end of the electrode assembly 10 facing the cover 22, and a second tab 12 is disposed at the end of the electrode assembly 10 facing the cover plate 40. The cover 22 is electrically connected to the second tab 12 via a cylindrical body 21.

[0146] The cylinder 21 can be directly connected to the second tab 12 to achieve an electrical connection between the cylinder 21 and the second tab 12. Alternatively, the cylinder 21 can also be connected to the second tab 12 through other conductive components to achieve an electrical connection between the cylinder 21 and the second tab 12.

[0147] By placing the first tab 11 and the second tab 12 at opposite ends of the electrode assembly 10, the distance between the first tab 11 and the second tab 12 can be increased, reducing the risk of conduction between the first tab 11 and the second tab 12 and improving safety. The cover 22 and the second tab 12 are electrically connected via the cylinder 21, eliminating the need for a separate component connecting the cover 22 and the second tab 12. Since the cover 22 and the cylinder 21 are an integral structure, the resistance at the connection point is low, thereby improving current carrying capacity.

[0148] In some embodiments, the second electrode 12 is the negative electrode, and the base material of the housing 20 is steel.

[0149] The base material is the main component in the material composition of the shell 20.

[0150] The housing 20 is electrically connected to the negative electrode tab, meaning the housing 20 is in a low potential state. The steel housing 20 is less susceptible to corrosion by the electrolyte in this low potential state.

[0151] In some embodiments, the electrode assembly 10 may be a cylinder.

[0152] The electrode assembly 10 has a central axis. The central axis of the electrode assembly 10 is a virtual straight line. The first electrode, the second electrode, and the separator can be wound with the central axis as a reference.

[0153] In some embodiments, the first tab 11 is wound multiple times around the central axis of the electrode assembly 10; in other words, the first tab 11 comprises multiple tab layers. After winding, the first tab 11 is generally cylindrical, with gaps between adjacent tab layers. Embodiments of this application can process the first tab 11 to reduce the gaps between tab layers, facilitating connection between the first tab 11 and other components. For example, embodiments of this application can flatten the first tab 11 to gather and aggregate the end regions of the first tab 11 away from the main body 13; the flattening process forms a dense end face at the end of the first tab 11 away from the main body 13, reducing the gaps between tab layers and facilitating connection between the first tab 11 and other components. Alternatively, embodiments of this application can also fill the gaps between adjacent tab layers with conductive material to reduce the gaps between tab layers.

[0154] In some embodiments, the second tab 12 is wound around the central axis of the electrode assembly 10 in multiple turns, and the second tab 12 includes multiple tab layers. Exemplarily, the second tab 12 is also flattened to reduce the gaps between the tab layers of the second tab 12.

[0155] In some embodiments, the second tab 12 is electrically connected to the cylinder 21 via the cover plate 40.

[0156] In some embodiments, the battery cell 7 further includes an adapter 51, which connects the cover plate 40 and the second tab 12 to electrically connect the second tab 12 to the cover plate 40. Specifically, the second tab 12 is electrically connected to the cover 22 via the adapter 51, the cover plate 40, and the cylindrical body 21.

[0157] Figure 8 This is a partial cross-sectional schematic diagram of the casing of a battery cell provided in some embodiments of this application.

[0158] Please refer to the above as well. Figures 5 to 8 In some embodiments, the cover 22 includes a body portion 2221 and a bent portion 223, the bent portion 223 being integrally connected to the cylinder 21 and the body portion 2221.

[0159] This embodiment does not limit the thickness of the main body 2221, the thickness of the bent part 223, and the wall thickness of the cylinder 21; the thickness of the three can be determined according to requirements.

[0160] The bent portion 223 surrounds the body portion 2221 and bends relative to the body portion 2221.

[0161] In this embodiment, the bending portion 223 can release stress during the forming process of the housing 20, reduce stress concentration, and lower the risk of the housing 20 breaking.

[0162] In some embodiments, the cover 22 is provided with a first electrode lead-out hole 221, which extends through the cover 22 to facilitate the lead-out of electrical energy from the electrode assembly 10 to the outside of the housing 20. Exemplarily, the first electrode lead-out hole 221 extends through the cover 22 along its thickness direction.

[0163] The first electrode lead-out hole 221 can be formed in the body portion 2221, that is, the first electrode lead-out hole 221 is directly surrounded by the body portion 2221. Alternatively, the first electrode lead-out hole 221 can also be formed in other parts of the cover 22.

[0164] The first electrode terminal 30 is used to mate with the first electrode lead-out hole 221 to cover the first electrode lead-out hole 221. The first electrode terminal 30 may extend into the first electrode lead-out hole 221 or may not extend into the first electrode lead-out hole 221. The first electrode terminal 30 is fixed to the cover 22. The first electrode terminal 30 may be fixed as a whole to the outside of the cover 22, or it may extend into the inside of the housing 20 through the first electrode lead-out hole 221.

[0165] In some embodiments, the cover 22 is electrically connected to the second tab 12. Optionally, at least a portion of the body 2221 is used to connect to the second busbar 82.

[0166] The body portion 2221 can be a plate-like structure. The plate-like structure of the body portion 2221 can better fit with the second busbar component 82, thereby ensuring the connection strength and flow area between the two.

[0167] The second busbar component 82 can be connected to the body 2221 by welding, bonding or other means to realize the electrical connection between the second busbar component 82 and the cover 22.

[0168] In some embodiments, the body portion 2221 is an annular plate-like structure that extends circumferentially along the first electrode lead-out hole 221 to surround the first electrode lead-out hole 221.

[0169] In some embodiments, the cylinder 21 is cylindrical, the first electrode lead-out hole 221 is a circular hole, and the central axis of the cylinder 21 and the central axis of the first electrode lead-out hole 221 are coincidentally arranged. "Coincidentally arranged" does not require that the central axis of the cylinder 21 and the central axis of the first electrode lead-out hole 221 are absolutely and completely coincident, and there may be deviations allowed by the process.

[0170] The first electrode lead-out hole 221 is used to define the position of the first electrode terminal 30. In this embodiment, the central axis of the first electrode lead-out hole 221 is aligned with the central axis of the cylinder 21, so that at least a portion of the first electrode terminal 30 is located at the center of the cover 22. In this way, when multiple battery cells 7 are assembled into a group, the positional accuracy requirement of the first electrode terminal 30 can be reduced, the assembly process can be simplified, and the assembly efficiency can be improved.

[0171] In some embodiments, the thickness of the body portion 2221 is greater than the wall thickness of the cylinder 21.

[0172] The thicker body portion 2221 can better support components such as the first electrode terminal 30; when the first electrode terminal 30 is subjected to external force, the thicker body portion 2221 deforms less. The cylindrical body 21 mainly isolates the electrode assembly 10 from the outside world, and it can have a relatively small thickness, thereby reducing the overall weight of the battery cell 7 and increasing the energy density.

[0173] In some embodiments, the body portion 2221 can be used to connect the second bus component 82. The body portion 2221 needs to have a large thickness to ensure the connection strength between the body portion 2221 and the second bus component 82.

[0174] For example, the body portion 2221 is welded to the second busbar component 82. If the thickness of the body portion 2221 is too small, the body portion 2221 is easily melted through during the welding process; therefore, the body portion 2221 in this embodiment of the application has a large thickness.

[0175] In some embodiments, the body portion 2221 is a flat plate structure with uniform thickness.

[0176] In some embodiments, the body portion 2221 has an inner surface 222a and an outer surface 222b disposed opposite to each other along its own thickness direction. The inner surface 222a of the body portion 2221 faces the electrode assembly 10, and the outer surface 222b of the body portion 2221 faces away from the electrode assembly 10. Optionally, both the inner surface 222a and the outer surface 222b are planar.

[0177] In some embodiments, the thickness D1 of the body portion 2221 and the wall thickness D2 of the cylinder 21 satisfy: 0.1 mm ≤ D1 - D2 ≤ 2 mm.

[0178] If D1-D2 is less than 0.1mm, then the thickness of the body 2221 will be too small or the thickness of the cylinder 21 will be too large. Too small a thickness of the body 2221 will result in insufficient strength, while too large a thickness of the cylinder 21 will result in excessive weight, affecting energy density. The shell 20 can be formed by stretching a flat plate. If D1-D2 is greater than 2mm, then during the stretching process, the difference between the stretching amount of the body 2221 and the stretching amount of the cylinder 21 will be too large, making the cylinder 21 prone to breakage during the stretching process.

[0179] After in-depth research and a large number of experiments, the inventors discovered that limiting the value of D1-D2 to 0.1mm-2mm can ensure that the strength of the casing 20 meets the requirements and reduce the loss of energy density of the battery cell 7.

[0180] Optionally, the values ​​of D1-D2 are 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm.

[0181] In some embodiments, the cover 22 includes a receiving recess 2222 recessed from the outer surface 222b of the body portion 2221 in the direction facing the electrode assembly 10. The bottom wall of the receiving recess 2222 is provided with a first electrode lead-out hole 221, and a first electrode terminal 30 is mounted in the first electrode lead-out hole 221.

[0182] The main body 2221 is disposed around the outer periphery of the receiving recess 2222. The first electrode lead-out hole 221 penetrates the bottom wall of the receiving recess 2222 and communicates the receiving recess 2222 with the interior of the housing 20.

[0183] By providing the receiving recess 2222, the size of the outer surface 222b of the protruding body portion 2221 of the first electrode terminal 30 can be reduced, thereby reducing the maximum size of the battery cell and increasing the energy density of the battery cell.

[0184] In some embodiments, the battery cell 7 further includes a first insulating member 61, and a receiving recess 2222 is configured to receive at least a portion of the first insulating member 61, wherein a portion of the first insulating member 61 received within the receiving recess 2222 is attached to the sidewall and / or bottom wall of the receiving recess 2222.

[0185] The first electrode terminal 30 is fixed to the cover 22. Exemplarily, the bottom wall of the receiving recess 2222 can be used to cooperate with and fix the first electrode terminal 30.

[0186] The first insulating member 61 is used to insulate at least a portion of the first electrode terminal 30 from the cover 22. Exemplarily, at least a portion of the first insulating member 61 is sandwiched between the bottom wall of the receiving recess 2222 and the first electrode terminal 30 to insulate the bottom wall of the receiving recess 2222 and the first electrode terminal 30, thereby reducing the risk of short circuit.

[0187] In this embodiment, either a portion of the first insulating member 61 is accommodated in the accommodating recess 2222, or the entire first insulating member 61 is accommodated in the accommodating recess 2222.

[0188] The portion of the first insulating member 61 housed within the receiving recess 2222 may be attached only to the side wall of the receiving recess 2222, or only to the bottom wall of the receiving recess 2222, or simultaneously to both the bottom wall and the side wall of the receiving recess 2222.

[0189] "Attachment" refers to the process of bringing two components into contact. This attachment can be both fixed and fixed, or it can simply be attached without fixation. For example, the first electrode terminal 30 and the bottom wall of the receiving recess 2222 clamp the portion of the first insulating member 61 contained within the receiving recess 2222 from both sides. Under the clamping force, the portion of the first insulating member 61 contained within the receiving recess 2222 is attached to the bottom wall of the receiving recess 2222. Alternatively, the portion of the first insulating member 61 contained within the receiving recess 2222 can also be attached to the bottom wall of the receiving recess 2222 using an adhesive.

[0190] In this embodiment, the first insulating member 61 can be positioned by providing the receiving recess 2222, simplifying the assembly process. The receiving recess 2222 can accommodate at least a portion of the first insulating member 61, thereby reducing the size of the outer surface 222b of the first insulating member 61 and the first electrode terminal 30 protruding from the body portion 2221, thus reducing the maximum size of the battery cell 7 and increasing the energy density.

[0191] In some embodiments, the outer surface 222b of the body portion 2221 is exposed and is not covered by the first electrode terminal 30 and the first insulating member 61.

[0192] In some embodiments, a cover protrusion 2223 is formed on the cover 22 at a position opposite to the receiving recess 2222, protruding from the inner surface 222a of the body portion 2221 in the direction facing the electrode assembly 10. By providing the cover protrusion 2223, this embodiment increases the thickness of the bottom wall of the receiving recess 2222, thereby improving the strength of the bottom wall of the receiving recess 2222 and enabling the bottom wall of the receiving recess 2222 to effectively support the first electrode terminal 30.

[0193] In some embodiments, the receiving recess 2222 and the cover protrusion 2223 can be formed by stamping the cover 22.

[0194] Figure 9 for Figure 6 Enlarged view at point C in the circle; Figure 10 This is a cross-sectional schematic diagram of a first electrode terminal provided for some embodiments of this application.

[0195] Please refer to the above as well. Figures 6 to 10 In some embodiments, the first electrode terminal 30 includes a first recess 31 and a first connecting portion 32 located at the bottom of the first recess 31. The first connecting portion 32 is used to achieve an electrical connection with the first tab 11 via the first solder portion W1.

[0196] The first recess 31 can be recessed from the side of the first electrode terminal 30 away from the electrode assembly 10 in the direction facing the electrode assembly 10, or it can be recessed from the side of the first electrode terminal 30 facing the electrode assembly 10 in the direction away from the electrode assembly 10.

[0197] The first connecting portion 32 is the portion of the first electrode terminal 30 that corresponds to the bottom surface of the first recess 31.

[0198] The first connecting part 32 is welded to other components to form a first welded part W1. Current is conducted through the first welded part W1 between the first electrode terminal 30 and the first electrode tab 11.

[0199] In some examples, the first connecting portion 32 can be directly welded to the first tab 11 to form the first weld portion W1. For example, a portion of the first connecting portion 32 and a portion of the first tab 11 melt and form a molten pool, which solidifies to form the first weld portion W1.

[0200] In other alternative examples, the first connection portion 32 is welded to other components (e.g., current collectors described later) connected to the first tab 11 to form the first weld portion W1. For example, a portion of the first connection portion 32 and a portion of the current collector melt to form a molten pool, which solidifies to form the first weld portion W1.

[0201] The embodiments of this application do not impose special limitations on the shape, position, depth, and number of the first welding portion W1. For example, the shape of the first welding portion W1 can be straight, C-shaped, annular, spiral, V-shaped, or other shapes. There can be one or more first welding portions W1.

[0202] In this embodiment, by forming a first recess 31 on the first electrode terminal 30, the thickness of the first connecting portion 32 is reduced, thereby reducing the welding power required for welding, reducing heat generation, lowering the risk of other components being burned, and improving safety. The first welding portion W1 can reduce the resistance between the first electrode terminal 30 and the first tab 11, improving the current carrying capacity.

[0203] For example, the welding equipment can irradiate a laser on the surface of the first connecting portion 32 facing the first recess 31. The laser melts a part of the first connecting portion 32 and a part of the component located inside the first connecting portion 32 to form a molten pool. After the molten pool solidifies, it forms the first welded portion W1.

[0204] In some embodiments, the battery cell 7 further includes a current collector 50 connected to the first tab 11. A first connection portion 32 is welded to the current collector 50 to form a first weld portion W1.

[0205] The current collector 50 electrically connects the first tab 11 to the first electrode terminal 30. This application does not limit the connection method between the first tab 11 and the current collector 50; for example, the current collector 50 can be connected to the first tab 11 by welding, abutting, or bonding.

[0206] Due to the size limitation of the first connecting portion 32, the number of tab layers that can be directly connected to the first connecting portion 32 on the first tab 11 is limited, affecting the uniformity of the current density of the first electrode. Compared to the first electrode terminal 30, the current collector 50 can have a larger connection area with the first tab 11, and the current collector 50 can be connected to more tab layers. By providing the current collector 50, the difference in current path between different positions of the first tab 11 and the first electrode terminal 30 can be reduced, improving the uniformity of the current density of the first electrode of the electrode assembly 10, reducing internal resistance, and improving overcurrent capacity.

[0207] In some embodiments, the first electrode terminal 30 includes a terminal body 34 and a sealing plate 33. The terminal body 34 includes a first recess 31 and a first connecting portion 32, with the first connecting portion 32 located on the side of the first recess 31 facing the electrode assembly 10. The sealing plate 33 is connected to the terminal body 34 and closes the opening of the first recess 31.

[0208] The sealing plate 33 can be located entirely outside the first recess 31, or it can be partially accommodated within the first recess 31, as long as the sealing plate 33 can close the opening of the first recess 31.

[0209] The sealing plate 33 can protect the first connection portion 32 from the outside, reduce the external impurities entering the first recess 31, reduce the risk of the first connection portion 32 being damaged by external impurities, and improve the sealing performance of the battery cell 7.

[0210] In some embodiments, at least a portion of the sealing plate 33 is accommodated in the first recess 31.

[0211] The sealing plate 33 can be entirely accommodated within the first recess 31, or it can be partially accommodated within the first recess 31.

[0212] The first recess 31 can provide a space for the sealing plate 33, thereby reducing the size of the sealing plate 33 protruding from the terminal body 34, reducing the space occupied by the first electrode terminal 30, and increasing the energy density of the battery cell 7.

[0213] In some embodiments, the sealing plate 33 can be used to connect to the first busbar component 81 of the battery. When it is necessary to weld the first busbar component 81 and the sealing plate 33, the first busbar component 81 is first attached to the upper surface of the sealing plate 33 (i.e., the outer surface of the sealing plate 33 facing away from the first connecting portion 32), and then the first busbar component 81 and the sealing plate 33 are welded.

[0214] In some embodiments, the sealing plate 33 protrudes from the terminal body 34 away from the surface of the electrode assembly 10.

[0215] At least a portion of the sealing plate 33 protrudes from the surface of the terminal body 34 away from the electrode assembly 10 to reduce the risk of the terminal body 34 interfering with the fit of the sealing plate 33 and the first bus component 81, thereby reducing the risk of poor soldering.

[0216] In some embodiments, a gap is provided between the sealing plate 33 and the first connecting portion 32. The gap can be used to avoid the first weld portion W1.

[0217] The surface of the first welded part W1 is uneven. If the sealing plate 33 presses against the first welded part W1, it will cause the sealing plate 33 to wobble during assembly, affecting the sealing effect. In this embodiment, a gap is provided between the sealing plate 33 and the first connecting part 32 to avoid direct contact between the sealing plate 33 and the first welded part W1, thereby reducing the wobble of the sealing plate 33 during assembly and ensuring the sealing effect.

[0218] In some embodiments, a stepped surface 311 is provided on the sidewall of the first recess 31, at least a portion of the sealing plate 33 is accommodated in the first recess 31, and the stepped surface 311 is used to support the sealing plate 33.

[0219] The first recess 31 is a stepped recess that is larger on the outside and smaller on the inside.

[0220] When assembling the sealing plate 33, the stepped surface 311 can support the sealing plate 33 and position it, thereby simplifying the assembly process and forming a gap between the sealing plate 33 and the first connecting part 32.

[0221] In some embodiments, the sealing plate 33 is welded to the sidewall of the first recess 31 to close the opening of the first recess 31.

[0222] In some embodiments, the first connecting portion 32 is provided with a groove 324 recessed from the first outer surface 322 of the first connecting portion 32 in the direction facing the electrode assembly 10.

[0223] The first connecting portion 32 has a first outer surface 322 and a first inner surface 321 disposed opposite to each other along its own thickness direction. The first inner surface 321 faces the electrode assembly 10, and the first outer surface 322 faces away from the electrode assembly 10. Optionally, both the first outer surface 322 and the first inner surface 321 are planar. The groove 324 is recessed relative to the first outer surface 322 in the direction facing the electrode assembly 10.

[0224] The portion between the bottom surface of the groove 324 and the first inner surface 321 is used for welding with other components to form the first welded portion W1.

[0225] In this embodiment, a groove 324 is formed in the first connecting portion 32 to create a stepped structure. A gap is formed between the first outer surface 322 and the bottom surface of the groove 324.

[0226] During the production of the battery cell 7, external equipment needs to cooperate with the first connecting part 32. The surface of the first welding part W1 is uneven, and if the external equipment is pressed onto the first welding part W1, the external equipment is easily damaged by the first welding part W1. In this embodiment, a groove 324 is provided to form a gap between the first outer surface 322 and the bottom surface of the groove 324. In this way, the first outer surface 322 can be used to support the external equipment, thereby separating the external equipment from the first welding part W1 and reducing the risk of the external equipment being damaged.

[0227] For example, the external device may be a liquid injection device, a vacuuming device, a welding device, or other device used for the battery cell 7.

[0228] In some embodiments, the first connection portion 32 is provided with a through hole 323 for injecting electrolyte.

[0229] There can be one or more through holes 323.

[0230] During the molding process of the battery cell 7, the through hole 323 connects the space outside the housing 20 with the internal space of the housing 20. When electrolyte injection is required, the injection head of the injection device presses against the first connection 32, and then the injection head injects electrolyte into the housing 20 through the through hole 323.

[0231] For example, during electrolyte injection, the injection head presses against the first outer surface 322, which can support the injection head and cooperate with it to achieve a seal, reducing the risk of electrolyte leakage to the outside of the battery cell 7.

[0232] By opening a through hole 323 for injecting electrolyte on the first connection portion 32 of the first electrode terminal 30, the deformation of the housing 20 during the electrolyte injection process can be reduced, the structure of the battery cell 7 can be simplified, and the influence of the through hole 323 on the strength of the housing 20 can be reduced.

[0233] In some embodiments, the sealing plate 33 is used to seal the through hole 323. After the process associated with the through hole 323 is completed, the sealing plate 33 is connected to the terminal body 34 to reduce the risk of electrolyte leakage through the through hole 323 and improve sealing performance.

[0234] In some embodiments, the through-hole 323 can also be applied to other processes, such as the formation process.

[0235] During the formation process of the battery cell 7, gas is generated inside the casing 20. The through hole 323 can also be used to connect with an external negative pressure device to extract the gas inside the casing 20.

[0236] In some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed opposite to each other. The second inner surface 345 faces the electrode assembly 10, and the second outer surface 344 faces away from the electrode assembly 10. A first recess 31 is recessed from the second outer surface 344 in the direction facing the electrode assembly 10 to the first outer surface 322 of the first connecting portion 32. At least a portion of the sealing plate 33 protrudes from the second outer surface 344 of the terminal body 34.

[0237] In some embodiments, the first connecting portion 32 is disposed at one end of the terminal body 34 facing the electrode assembly 10, and the first inner surface 321 of the first connecting portion 32 is flush with the second inner surface 345.

[0238] The second inner surface 345 is the surface of the terminal body 34 facing the electrode assembly 10. The first inner surface 321 of the first connecting portion 32 forms a part of the second inner surface 345. In this way, the terminal body 34 can mate with the current collector 50 having a flat plate structure. In this embodiment, the first connecting portion 32 and the current collector 50 can be attached to the second inner surface 345 to facilitate welding of the first connecting portion 32 and the current collector 50.

[0239] In some embodiments, the terminal body 34 includes a columnar portion 341, a first limiting portion 342, and a second limiting portion 343. At least a portion of the columnar portion 341 is located inside the first electrode lead-out hole 221. A first recess 31 is provided in the columnar portion 341. The first limiting portion 342 and the second limiting portion 343 are both connected to and protrude from the outer side wall of the columnar portion 341. The first limiting portion 342 and the second limiting portion 343 are respectively provided on the outer side and the inner side of the cover 22 and are used to clamp a portion of the cover 22.

[0240] The first limiting part 342 is located on the outer side of the cover 22, meaning that the first limiting part 342 is located on the side of the cover 22 away from the electrode assembly 10; the second limiting part 343 is located on the inner side of the cover 22, meaning that the second limiting part 343 is located on the side of the cover 22 facing the electrode assembly 10.

[0241] In the thickness direction of the cover 22, at least a portion of the first limiting portion 342 overlaps with the cover 22, and at least a portion of the second limiting portion 343 overlaps with the cover 22. A columnar portion 341 passes through the first electrode lead-out hole 221 to connect the first limiting portion 342 and the second limiting portion 343 located on both sides of the cover 22.

[0242] The first limiting part 342 and the second limiting part 343 clamp a portion of the cover 22 from both sides to fix the terminal body 34 to the cover 22. The first limiting part 342 and the second limiting part 343 can clamp the cover 22 directly or indirectly through other components.

[0243] Optionally, the columnar portion 341 is cylindrical. The first limiting portion 342 and the second limiting portion 343 are both annular structures surrounding the columnar portion 341.

[0244] In some embodiments, at least a portion of the first insulating member 61 is disposed between the first limiting portion 342 and the cover 22. Exemplarily, at least a portion of the first insulating member 61 is disposed between the first limiting portion 342 and the bottom surface of the receiving recess 2222. The first insulating member 61 is capable of insulating and isolating the first limiting portion 342 from the cover 22.

[0245] In some embodiments, the battery cell 7 further includes a second insulating member 62, at least a portion of which is disposed between the second limiting portion 343 and the cover 22. Exemplarily, at least a portion of the second insulating member 62 is disposed between the second limiting portion 343 and the top surface of the cover protrusion 2223.

[0246] The second insulating member 62 is capable of insulating at least a portion of the second limiting portion 343 from the cover 22.

[0247] In some embodiments, the first insulating member 61 and the second insulating member 62 are both annular structures arranged around the columnar portion 341.

[0248] In some embodiments, the battery cell 7 further includes a sealing ring 63, which is fitted onto the columnar portion 341 and used to seal the first electrode lead-out hole 221. Optionally, a portion of the sealing ring 63 extends into the first electrode lead-out hole 221 to separate the hole wall of the first electrode lead-out hole 221 from the columnar portion 341.

[0249] Figure 11 This is a partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0250] like Figure 11 As shown, in some embodiments, the first connecting portion 32 is welded to the first tab 11 to form the first welding portion W1.

[0251] The battery cell 7 in this embodiment can omit the current collector, thereby simplifying the internal structure of the battery cell, shortening the conductive path between the first electrode terminal 30 and the first tab 11, reducing resistance, and improving the energy density and overcurrent capability of the battery cell 7.

[0252] Figure 12 A cross-sectional schematic diagram of a battery cell provided for other embodiments of this application; Figure 13 for Figure 12 Enlarged view of box D.

[0253] like Figure 12 and Figure 13 As shown, in some embodiments, the cover plate 40 is sealed to the cylinder 21 by a seal 70. By providing the seal 70 between the cover plate 40 and the cylinder 21, the sealing performance of the battery cell 7 can be improved.

[0254] For example, the connection between the cover plate 40 and the cylinder 21 may be the area where the cover plate 40 and the cylinder 21 jointly clamp the seal 70.

[0255] In some embodiments, the cylinder 21 includes a support portion 212 and a flange portion 213, which are arranged along the axial direction X of the cylinder 21. At least a portion of the cover plate 40 is clamped between the support portion 212 and the flange portion 213 along the axial direction X of the cylinder 21 to fix the cover plate 40.

[0256] In some embodiments, the seal 70 covers the outer periphery of the cover plate 40. In the axial direction X of the cylinder 21, a portion of the seal 70 is clamped between the support portion 212 and the cover plate 40, and a portion is clamped between the flange portion 213 and the cover plate 40, thereby achieving a seal on the opening 211 of the cylinder 21.

[0257] In some embodiments, after the electrode assembly 10 is placed inside the housing 20, the cylinder 21 is rolled from the outside to form an inwardly protruding support portion 212 on the cylinder 21. After the support portion 212 is formed, the cover plate 40 and the sealing member 70 covering the cover plate 40 are placed inside the cylinder 21, and then the end of the cylinder 21 is bent by a flanging process to form a flanged portion 213 on the cylinder 21.

[0258] In some embodiments, the second electrode 12 is electrically connected to the cylinder 21 via an adapter 51.

[0259] In some embodiments, the adapter 51 is welded to the support portion 212 of the cylinder 21 to electrically connect the cylinder 21 and the second tab 12.

[0260] In some embodiments, the seal 70 insulates the cover plate 40 and the cylinder 21.

[0261] Figure 14 This is a schematic diagram of the battery structure provided in some other embodiments of this application; Figure 15 A top view schematic diagram of a battery cell provided for other embodiments of this application; Figure 16 for Figure 15 A cross-sectional view of the EE along the line.

[0262] like Figures 14 to 16 As shown, in some embodiments, the electrode assembly 10 further includes a second tab 12, the polarity of which is opposite to that of the first tab 11. The battery cell 7 also includes a second electrode terminal 90 electrically connected to the second tab 12, the second electrode terminal 90 being used to connect to the second busbar 82 of the battery.

[0263] The second electrode terminal 90 can be disposed on the cover 22 or on the cover plate 40.

[0264] The second electrode terminal 90 can be directly connected to the second electrode tab 12 to achieve an electrical connection between the second electrode terminal 90 and the second electrode tab 12. Exemplarily, the second electrode terminal 90 can be connected to the second electrode tab 12 by adhesive bonding, abutment, snap-fitting, welding, or other methods.

[0265] Alternatively, the second electrode terminal 90 can also be indirectly connected to the second electrode tab 12 via other conductive components to achieve an electrical connection between the second electrode terminal 90 and the second electrode tab 12. For example, a conductive component can be simultaneously connected to both the second electrode tab 12 and the second electrode terminal 90 to achieve an electrical connection between the second electrode terminal 90 and the second electrode tab 12.

[0266] The busbar component used for electrical connection with the second electrode terminal 90 of the battery cell 7 can be referred to as the second busbar component 82 corresponding to the battery cell 7. The second busbar component 82 can be connected to the second electrode terminal 90 by welding, bonding or other means to realize the electrical connection between the second busbar component 82 and the second electrode terminal 90.

[0267] For example, the first busbar 81 connects the first electrode terminal 30 of one battery cell 7 to the second electrode terminal 90 of another battery cell 7, while the second busbar 82 connects the second electrode terminal 90 of the one battery cell 7 to the first electrode terminal 30 of yet another battery cell 7. In this way, the first busbar 81 and the second busbar 82 connect the three battery cells 7 in series.

[0268] The first electrode terminal 30 and the second electrode terminal 90 can serve as the two output electrodes of the battery cell 7 to realize the electrical connection between the battery cell 7 and the external circuit.

[0269] The second electrode terminal 90 replaces the cover 22 as the output electrode, which can reduce the welding stress on the cover 22 and reduce the strength requirements of the housing 20.

[0270] In some embodiments, the second electrode terminal 90 is disposed on the cover 22.

[0271] The first electrode terminal 30 and the second electrode terminal 90 are located at the same end of the battery cell 7. This allows the first busbar component 81 and the second busbar component 82 to be assembled onto the same side of the battery cell 7, simplifying the assembly process and improving the efficiency of assembling multiple battery cells 7 into a group. The second electrode terminal 90 is positioned on the cover 22 away from the cover plate 40 to increase the distance between the connection between the cylinder 21 and the cover plate 40 and the second electrode terminal 90. This reduces the impact on the connection between the cylinder 21 and the cover plate 40 when the battery cell 7 is subjected to external impact, lowers the risk of connection failure between the cover plate 40 and the housing 20, reduces electrolyte leakage, and improves safety.

[0272] In some embodiments, the cover 22 is further provided with a second electrode lead-out hole. The second electrode terminal 90 is mounted in the second electrode lead-out hole.

[0273] In some embodiments, the first electrode terminal 30 and the second electrode terminal 90 both protrude from the outer surface of the cover 22 to reduce the risk of the cover 22 interfering with the busbar component and to simplify the connection process between the busbar component and the electrode terminal.

[0274] In some embodiments, both the first electrode terminal 30 and the second electrode terminal 90 are insulated from the cover 22.

[0275] This embodiment can make the housing 20 non-energized, thereby reducing the risk of leakage and improving safety.

[0276] In some embodiments, the base material of the housing 20 is aluminum. The aluminum housing 20 has a lighter weight, which increases the energy density of the battery cell 7. Since the housing 20 is not charged, the aluminum housing 20 is less susceptible to corrosion by the electrolyte.

[0277] In some embodiments, the electrode assembly 10 further includes a body portion 13. The first electrode tab 11 and the second electrode tab 12 both extend from the end of the body portion 13 facing the cover 22 to reduce the distance between the first electrode tab 11 and the first electrode terminal 30 and the distance between the second electrode tab 12 and the second electrode terminal 90.

[0278] In some embodiments, the first electrode terminal 30 includes a terminal body 34 and a sealing plate 33. The terminal body 34 includes a first recess 31 and a first connecting portion 32, the first connecting portion 32 being located on the side of the first recess 31 facing the electrode assembly 10. The sealing plate 33 is connected to the terminal body 34 and closes the opening of the first recess 31.

[0279] In some alternative embodiments, a through-hole for liquid injection can be provided on the cover 22 or the cover plate 40. Correspondingly, the through-hole on the first connecting portion 32 can be omitted. The sealing plate 33 of the first electrode terminal 30 can be retained or omitted.

[0280] In some embodiments, the electrode assembly 10 further includes a second tab 12, the polarity of which is opposite to that of the first tab 11. The battery cell 7 also includes a second electrode terminal 90 disposed on the cover 22, the second electrode terminal 90 including a second recess 91 and a second connecting portion 92 located at the bottom of the second recess 91. The second connecting portion 92 is used to achieve an electrical connection with the second tab 12 via a second welding portion W2.

[0281] In some examples, the second connecting portion 92 can be directly welded to the second tab 12 to form the second weld portion W2. For example, a portion of the second connecting portion 92 and a portion of the second tab 12 melt and form a molten pool, which solidifies to form the second weld portion W2.

[0282] In other alternative examples, the second connection 92 is welded to other components (e.g., another current collector 52) connected to the second tab 12 to form the second welded portion W2. For example, a portion of the second connection 92 and a portion of the current collector 52 melt and form a molten pool, which solidifies to form the second welded portion W2.

[0283] In this embodiment, the thickness of the second connecting portion 92 is reduced by forming a second recess 91 on the second electrode terminal 90, thereby reducing the welding power required for welding, reducing heat generation, lowering the risk of other components being burned, and improving safety. The second welding portion W2 can reduce the resistance between the second electrode terminal 90 and the second tab 12, improving the overcurrent capacity.

[0284] In some embodiments, the second electrode terminal 90 may have the same structure as the first electrode terminal 30. In other words, the second electrode terminal 90 also includes a terminal body and a sealing plate.

[0285] In some embodiments, the battery cell 7 may be a square battery cell. Exemplarily, the cylindrical body 21 may be a square cylinder.

[0286] In some embodiments, the cover 22 may be rectangular, and the electrode assembly 10 may be flat. The first electrode lead-out hole and the second electrode lead-out hole may be respectively located near the two ends of the cover 22 along its own length direction.

[0287] According to some embodiments of this application, a battery is also provided, comprising a plurality of battery cells of any of the above embodiments.

[0288] According to some embodiments of this application, an electrical device is also provided, including the battery of any of the above embodiments, the battery being used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize a single battery cell.

[0289] Reference Figures 4 to 10 This application provides a cylindrical battery cell 7, which includes an electrode assembly 10, a housing 20, a first electrode terminal 30, a current collector 50, and a cover plate 40. The housing 20 includes an integrally formed cylindrical body 21 and a cover 22, with the cylindrical body 21 having an opening 211 at the end opposite to the cover 22. The electrode assembly 10 is housed within the housing 20 and includes a first tab 11 and a second tab 12. The polarity of the second tab 12 is opposite to that of the first tab 11. The first tab 11 is located at the end of the electrode assembly 10 facing the cover 22, and the second tab 12 is located at the end of the electrode assembly 10 facing the cover plate 40.

[0290] The cover plate 40 is connected to the cylinder 21 and closes the opening. The cover 22 is electrically connected to the second electrode lug 12 through the cylinder 21.

[0291] The first electrode terminal 30 includes a terminal body 34 and a sealing plate 33. The terminal body 34 includes a first recess 31 and a first connecting portion 32 located at the bottom of the first recess 31. A current collector 50 is welded to the first tab 11 and the first connecting portion 32 to electrically connect the terminal body 34 to the first tab 11. At least a portion of the sealing plate 33 is accommodated in the first recess 31 and closes the opening of the first recess 31. The sealing plate 33 is welded to the terminal body 34.

[0292] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0293] Finally, it should be noted that 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 they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these 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.

Claims

1. A battery cell, characterized in that, include: The housing includes an integrally formed cylindrical body and a cover, the cylindrical body having an opening at one end opposite to the cover; An electrode assembly is housed within the housing. The electrode assembly is wound and includes a first electrode tab and a second electrode tab, wherein the polarity of the second electrode tab is opposite to that of the first electrode tab. A first electrode terminal is disposed on the cover and used for electrical connection with the first electrode tab. The first electrode terminal is insulated from the housing and is used for connection with the first current-carrying component of the battery. A cover plate is connected to the cylindrical body and covers the opening. The cover plate is electrically connected to the second tab and is used to connect to the second busbar component of the battery. The first tab is located at the end of the electrode assembly facing the cover plate, and the second tab is located at the end of the electrode assembly facing the cover plate. The cover plate is electrically connected to the second tab through the cylindrical body.

2. The battery cell according to claim 1, characterized in that, The cover plate is welded to the cylinder.

3. The battery cell according to claim 1, characterized in that, The cover plate is sealed to the cylinder by a sealing element.

4. The battery cell according to claim 1, characterized in that, The second electrode tab is the negative electrode tab, and the base material of the shell is steel.

5. The battery cell according to any one of claims 1-4, characterized in that, The cover includes a main body and a bent portion, the bent portion being integrally connected to the cylinder and the main body.

6. The battery cell according to claim 5, characterized in that, The thickness of the main body is greater than the wall thickness of the cylinder.

7. The battery cell according to claim 5, characterized in that, The cover includes a receiving recess that is recessed from the outer surface of the body portion in a direction facing the electrode assembly; The bottom wall of the receiving recess is provided with a first electrode lead-out hole, and the first electrode terminal is installed in the first electrode lead-out hole.

8. The battery cell according to claim 5, characterized in that, The thickness D1 of the main body and the wall thickness D2 of the cylinder satisfy the following condition: 0.1 mm ≤ D1 - D2 ≤ 2 mm.

9. The battery cell according to any one of claims 1-4, characterized in that, The first electrode terminal includes a first recess and a first connecting portion located at the bottom of the first recess; The first connecting part is used to achieve an electrical connection with the first electrode tab through the first welding part.

10. The battery cell according to claim 9, characterized in that, The first connecting portion is welded to the first electrode tab to form the first welded portion.

11. The battery cell according to claim 9, characterized in that, It also includes a current collection component connected to the first electrode tab; The first connecting portion is welded to the current collecting member to form the first welded portion.

12. The battery cell according to claim 9, characterized in that, The first electrode terminal includes a terminal body and a sealing plate. The terminal body includes a first recess and a first connecting portion. The first connecting portion is located on the side of the first recess facing the electrode assembly. The sealing plate is connected to the terminal body and closes the opening of the first recess.

13. The battery cell according to claim 12, characterized in that, At least a portion of the sealing plate is accommodated in the first recess.

14. The battery cell according to claim 13, characterized in that, The sealing plate protrudes from the surface of the terminal body away from the electrode assembly.

15. The battery cell according to claim 12, characterized in that, A gap is provided between the sealing plate and the first connecting part.

16. The battery cell according to claim 9, characterized in that, The first connecting part is provided with a through hole for injecting electrolyte.

17. The battery cell according to claim 9, characterized in that, The electrode assembly further includes a second electrode tab, the polarity of which is opposite to that of the first electrode tab; The battery cell also includes a second electrode terminal disposed on the cover, the second electrode terminal including a second recess and a second connecting portion located at the bottom of the second recess; The second connecting part is used to achieve an electrical connection with the second electrode tab through the second welding part.

18. A battery, characterized in that, It includes multiple battery cells according to any one of claims 1-17.

19. An electrical appliance, characterized in that, Includes the battery according to claim 18, the battery being used to provide electrical energy.

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