Battery cell, method and system for manufacturing the same, battery, and electric device

Abstract

This application provides a battery cell, a manufacturing method and system thereof, a battery, and an electrical device. The battery cell of this application includes: an electrode assembly including a first tab disposed around the central axis of the electrode assembly; a housing for housing the electrode assembly, the housing including a cylindrical body and a cover connected to the cylindrical body, the cylindrical body being disposed around the outer periphery of the electrode assembly, the cover and the cylindrical body being integrally formed, the cover having an electrode lead-out hole, the central axis extending along a first direction and passing through the electrode lead-out hole, the first tab including a first annular portion disposed opposite to the cover, and the projection of the first annular portion in the first direction not overlapping the projection of the electrode lead-out hole in the first direction; an electrode terminal mounted in the electrode lead-out hole; and a current collector, at least partially located between the cover and the first annular portion, the current collector connecting the first annular portion and the electrode terminal to electrically connect the first tab and the electrode terminal.

Description

[0001] This application is a divisional application based on application number 202180081084.4, filed on August 23, 2021, by CATL (Contemporary Amperex Technology Co., Limited), entitled "Battery cell and manufacturing method and system thereof, battery and electrical device". Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery cell and its manufacturing method and system, a battery, and an electrical device. Background Technology

[0003] 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.

[0004] In the development of battery technology, how to improve the overcurrent capacity of individual battery cells is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a battery cell, a method and system for manufacturing the same, a battery, and an electrical device, which can improve the overcurrent capability of the battery cell.

[0006] In a first aspect, embodiments of this application provide a single battery cell, comprising: An electrode assembly includes a first electrode tab, which is arranged around the central axis of the electrode assembly. A housing for accommodating an electrode assembly, the housing including a cylindrical body and a cover connected to the cylindrical body, the cylindrical body being disposed around the outer periphery of the electrode assembly, the cover having an electrode lead-out hole, the central axis extending along a first direction and passing through the electrode lead-out hole, the first electrode tab including a first annular portion, the first annular portion being disposed opposite to the cover, and the projection of the first annular portion in the first direction not overlapping with the projection of the electrode lead-out hole in the first direction. Electrode terminals, mounted in electrode lead-out holes; and A current collector, at least partially located between the cover and the first annular portion, is used to connect the first annular portion and the electrode terminal so that the first tab and the electrode terminal are electrically connected.

[0007] In the above scheme, a current collector is set to connect the electrode terminal and the first annular portion of the first tab. In this way, the current in the electrode assembly can flow to the electrode terminal through the first annular portion and the current collector, thereby shortening the conductive path and improving the overcurrent capacity and charging efficiency of the battery cell.

[0008] In some embodiments, the central axis coincides with the axis of the electrode lead-out hole. The electrode lead-out hole is generally located in the middle of the cover, and correspondingly, the electrode terminals are also mounted in the middle of the cover. When multiple battery cells are assembled into a group, the positioning accuracy requirements of the electrode terminals can be reduced, simplifying the assembly process.

[0009] In some embodiments, the first annular portion is welded to the current collector to form a first welded portion. The first welded portion can reduce the contact resistance between the current collector and the first annular portion, thereby improving the current carrying capacity.

[0010] In some embodiments, the cross-section of the first electrode tab perpendicular to the first direction is annular. The outer radius of the first electrode tab is R, and the minimum distance between the first welded part and the central axis in the second direction is D, both satisfying: 0.2≤D / R≤0.8, where the second direction is the radial direction of the first electrode tab.

[0011] In the above scheme, the values ​​of D and R are set to 0.2≤D / R≤0.8. This can reduce the difference in current path between the parts of the first electrode tab at different positions and the electrode terminals, improve the uniformity of current density of the first electrode plate of the electrode assembly, reduce internal resistance, and improve overcurrent capability.

[0012] In some embodiments, the first weld portion is annular and arranged around a central axis. The annular first weld portion has a large current-carrying area, which can improve the uniformity of the current density of the first electrode, reduce internal resistance, and improve current-carrying capacity. In some embodiments, there are multiple first weld portions, which are arranged at circumferential intervals along the first annular portion. Multiple first weld portions can increase the current-carrying area, improve the uniformity of the current density of the first electrode, reduce internal resistance, and enhance current-carrying capacity.

[0013] In some embodiments, the current collector has a protrusion on the side facing the first electrode tab, and the protrusion is welded to the first annular portion to form a first weld portion. The protrusion can better fit with the first annular portion, reducing the risk of poor welding.

[0014] In some embodiments, the first electrode tab further includes a second annular portion disposed opposite to the electrode lead-out hole along a first direction, and the first annular portion surrounds the outer side of the second annular portion. At least a portion of the second annular portion abuts against the current collector.

[0015] In the above scheme, the flow capacity can be improved by setting the second annular portion. The second annular portion can also support the first annular portion radially, so as to reduce the risk of the first annular portion being crushed and deformed when welding the first annular portion and the current collecting component, and improve the welding stability of the first annular portion and the current collecting component.

[0016] In some embodiments, the electrode terminal includes a terminal body having a first recess. A connecting portion is formed at the bottom of the first recess on the terminal body, and the connecting portion is welded to the current collector to form a second welded portion.

[0017] In the above solution, the thickness of the connecting part is reduced by setting the first recess, which reduces the welding power required to weld the connecting part to the current collector, reduces heat generation, and lowers the risk of other components being burned.

[0018] In some embodiments, a portion of the first recess is located within the electrode lead-out hole.

[0019] In some embodiments, a stress-relieving structure is provided on the connection portion to release stress during welding of the connection portion and the current collector. This embodiment uses the stress-relieving structure to release stress, thereby reducing the risk of deformation and cracking of the connection portion during welding and ensuring the connection strength between the connection portion and the current collector.

[0020] In some embodiments, the connector is provided with a first through hole, which connects the space on the side of the connector away from the electrode assembly to the internal space of the housing. During welding of the connector and the current collector, the first through hole can relieve welding stress and reduce the risk of connector breakage. The first through hole can also be used for processes such as liquid injection and air extraction.

[0021] In some embodiments, the first through-hole is used to inject electrolyte into the internal space of the housing.

[0022] In some embodiments, the current collector is provided with a second through hole, which is configured to be opposite to the first through hole so that the electrolyte can flow into the internal space of the housing through the second through hole.

[0023] In the above scheme, by setting a second through hole on the current collector that is opposite to the first through hole, the obstruction of the current collector to the electrolyte during the liquid injection process can be reduced, so that the electrolyte can flow smoothly into the shell and improve the wetting efficiency of the electrode assembly.

[0024] In some embodiments, the projection of the first through-hole along the first direction lies within the projection of the second through-hole along the first direction. This embodiment can prevent the current collector from blocking the first through-hole in the first direction, allowing the electrolyte to flow smoothly into the housing.

[0025] In some embodiments, the electrode assembly is a wound structure, and the electrode assembly has a third through hole at the center of the winding. The third through hole extends through the electrode assembly along a first direction, and the third through hole is disposed opposite to the first through hole and the second through hole along the first direction, so that electrolyte can flow into the interior of the electrode assembly through the third through hole. The electrolyte can flow into the third through hole through the first through hole and the second through hole, and the electrolyte flowing into the third through hole can wet the electrode assembly from the inside, thereby improving the wetting efficiency of the electrode assembly.

[0026] In some embodiments, the projection of the second through-hole along the first direction lies within the projection of the third through-hole along the first direction. This embodiment can reduce the obstruction of the second through-hole by the first electrode tab, allowing the electrolyte to flow smoothly into the third through-hole.

[0027] In some embodiments, the connection includes a groove, the bottom wall of which is formed with a second welding portion, the groove being configured to be recessed from a first outer surface of the connection in a direction facing the electrode assembly, such that a gap is formed between the first outer surface and the bottom wall of the groove.

[0028] During the production of a battery cell, external equipment can mate with the connecting part. The surface of the second welding part is uneven, and if the external equipment is pressed onto the second welding part, it is easily damaged by the second welding part. This embodiment provides a groove to form a gap between the first outer surface and the bottom wall of the groove. In this way, the first outer surface can be used to support the external equipment, thereby separating the external equipment from the second welding part and reducing the risk of the external equipment being damaged.

[0029] In some embodiments, the terminal body includes a columnar portion, a first limiting portion, and a second limiting portion. At least a portion of the columnar portion is located within an electrode lead-out hole. A first recess is provided in the columnar portion. Both the first limiting portion and the second limiting portion are connected to and protrude from the outer side wall of the columnar portion. The first limiting portion and the second limiting portion are respectively located on the outer and inner sides of the cover body along a first direction and are used to clamp a portion of the cover body. The first limiting portion and the second limiting portion clamp a portion of the cover body from both sides to fix the terminal body to the cover body.

[0030] In some embodiments, the columnar portion, the first limiting portion, and the second limiting portion are an integral structure.

[0031] In some embodiments, the battery cell further includes a first insulating member and a second insulating member, at least a portion of the first insulating member being disposed between the first limiting portion and the cover, and at least a portion of the second insulating member being disposed between the second limiting portion and the cover. The first insulating member and the second insulating member are used to insulate and isolate the terminal body from the cover.

[0032] In some embodiments, the first insulating member and the second insulating member are integrally formed into a structure; or, the first insulating member and the second insulating member are provided separately and abut against each other.

[0033] In some embodiments, one of the first insulating member and the second insulating member is used to seal the electrode lead-out hole.

[0034] In some embodiments, the outer periphery of the first limiting portion is provided with a plurality of protrusions, which are spaced apart circumferentially along the columnar portion. Adjacent protrusions are separated by grooves. This embodiment reduces the difficulty of folding the first limiting portion and decreases stress concentration on the first limiting portion by providing both groove and protrusion structures.

[0035] In some embodiments, the first limiting portion is a flange structure formed by folding outward from the end of the terminal body away from the electrode assembly.

[0036] In some embodiments, the second limiting portion is a limiting structure formed by pressing the end of the terminal body facing the electrode assembly to extend the end of the terminal body facing the electrode assembly outward.

[0037] In some embodiments, the terminal body has a second outer surface and a second inner surface disposed opposite to each other along a first direction, and a first recess is recessed from the second outer surface to the first outer surface of the connection portion along the direction facing the electrode assembly.

[0038] In some embodiments, the electrode terminal further includes a sealing plate, which is connected to the terminal body and closes the opening of the first recess. The sealing plate can protect the connection from the outside, reduce the amount of external impurities entering the first recess, reduce the risk of damage to the connection from external impurities, and improve the sealing performance of the battery cell.

[0039] In some embodiments, a stepped surface is provided on the sidewall of the first recess, at least a portion of the sealing plate is accommodated in the first recess, and the stepped surface is used to support the sealing plate.

[0040] During assembly of the sealing plate, the stepped surface can support and position the sealing plate, thereby simplifying the assembly process. At least a portion of the sealing plate is accommodated in the first recess, which reduces the overall size of the electrode terminal, decreases the space occupied by the electrode terminal, and increases the energy density.

[0041] In some embodiments, a gap is provided between the sealing plate and the connecting portion to avoid the second welding portion. This embodiment, by providing a gap between the sealing plate and the connecting portion, avoids direct contact between the sealing plate and the second welding portion, reduces the shaking of the sealing plate during assembly, and ensures a sealing effect.

[0042] In some embodiments, the connecting portion is disposed at one end of the terminal body facing the electrode assembly, and the first inner surface and the second inner surface of the connecting portion are flush.

[0043] In some embodiments, the terminal body further includes a second recess that is recessed from the second inner surface in a direction away from the electrode assembly to the first inner surface of the connection portion.

[0044] This embodiment of the application reduces the thickness of the connecting portion by simultaneously providing a first recess and a second recess. This reduces the depth requirement for the first recess and simplifies the molding process. Providing the second recess also increases the internal space of the battery cell, thereby improving energy density.

[0045] In some embodiments, the current collector includes a terminal connection portion and a tab connection portion surrounding the outside of the terminal connection portion. The terminal connection portion protrudes relative to the tab connection portion and extends into the second recess, such that the top of the terminal connection portion abuts against the first inner surface of the connection portion.

[0046] In some embodiments, the terminal body has a second outer surface and a second inner surface disposed opposite to each other along a first direction, and a first recess is recessed from the second inner surface to the first inner surface of the connection portion in a direction away from the electrode assembly.

[0047] The above solution places the first recess on the inner side of the terminal body, which ensures the flatness and area of ​​the second outer surface, facilitating the connection between the terminal body and external busbar components. Furthermore, by providing the first recess on the inner side of the terminal body, the internal space of the battery cell can be increased, thereby improving energy density.

[0048] In some embodiments, the current collector includes a terminal connection portion and a tab connection portion surrounding the outside of the terminal connection portion. The terminal connection portion protrudes relative to the tab connection portion and extends into a first recess, such that the top of the terminal connection portion abuts against the first inner surface of the connection portion.

[0049] In some embodiments, the terminal body has a second outer surface and a second inner surface disposed opposite each other along a first direction, and a first recess extends from the second outer surface into the first outer surface of the connection portion in a direction facing the electrode assembly. The electrode terminal also includes a sealing plate connected to the terminal body and closing the opening of the first recess. The sealing plate is used to weld to a current-carrying component of the battery to form a third weld portion. The third weld portion can reduce the contact resistance between the sealing plate and the current-carrying component, improving the current-carrying capacity.

[0050] In some embodiments, at least a portion of the sealing plate protrudes from the second outer surface of the terminal body. This protrusion of the sealing plate from the second outer surface prevents the second outer surface from interfering with the fit between the sealing plate and the busbar component, ensuring a tight fit between the busbar component and the sealing plate.

[0051] In some embodiments, at least a portion of the sealing plate is accommodated in the first recess, and the sidewall of the first recess has a stepped surface for supporting the sealing plate. The sealing plate is welded to the sidewall of the first recess to form a fourth welded portion, which is used to seal the opening of the first recess.

[0052] In the above scheme, the fourth welding part surrounds the outer periphery of the sealing plate to seal the gap between the sealing plate and the side wall of the first recess, thereby improving the sealing performance of the battery cell.

[0053] In some embodiments, the third weld portion is entirely located within the area enclosed by the fourth weld portion. This embodiment can avoid the intersection of the third and fourth weld portions when welding the busbar and the sealing plate, thereby reducing the risk of incomplete welds.

[0054] In some embodiments, the cover and the cylinder are integrally formed. This eliminates the need for the connection process between the cover and the cylinder.

[0055] In some embodiments, the electrode assembly further includes a second tab disposed around the central axis of the electrode assembly. The first and second tabs are respectively located at both ends of the electrode assembly along a first direction. The cylindrical body is used to connect the second tab and the cover to enable electrical connection between the second tab and the cover.

[0056] In the above scheme, the cover and the electrode terminals have different polarities. In this case, one of the cover and the electrode terminals can serve as the positive output terminal of the battery cell, and the other as the negative output terminal. This embodiment places the positive and negative output terminals on the same side of the battery cell, which simplifies the connection process between multiple battery cells.

[0057] In some embodiments, the second tab is the negative tab, and the base material of the housing is steel. The housing is electrically connected to the negative tab, meaning the housing is in a low potential state. The steel housing is less susceptible to corrosion by the electrolyte in a low potential state.

[0058] In some embodiments, the cylinder has an opening at one end away from the cover, and the battery cell also includes a cover for closing the opening.

[0059] In some embodiments, the cylindrical battery cell includes an electrode assembly, a housing, electrode terminals, and a current collector. The electrode assembly includes a first tab disposed around a central axis of the electrode assembly. The housing houses the electrode assembly and includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body surrounds the outer periphery of the electrode assembly, and the cover has an electrode lead-out hole. The central axis extends along a first direction and passes through the electrode lead-out hole. The first tab includes a first annular portion disposed opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. The electrode terminals are mounted in the electrode lead-out hole. At least a portion of the current collector is located between the cover and the first annular portion, and the current collector connects the first annular portion and the electrode terminals, thereby electrically connecting the first tab and the electrode terminals. The electrode terminal includes a terminal body, which includes a columnar portion, a first limiting portion, and a second limiting portion. The columnar portion, the first limiting portion, and the second limiting portion are integral structures. At least a portion of the columnar portion is located inside the electrode lead-out hole. The first limiting portion and the second limiting portion are connected and protrude from the outer side wall of the columnar portion. The first limiting portion and the second limiting portion are respectively located on the outer and inner sides of the cover along the first direction and are used to clamp a portion of the cover. The terminal body has a first recess, which is located in the columnar portion. A connecting portion is formed at the bottom of the first recess. The connecting portion is welded to the current collector and forms a second welding portion. The terminal body has a second outer surface and a second inner surface that are arranged opposite to each other along the first direction. The first recess extends from the second outer surface to the first outer surface of the connecting portion along the direction facing the electrode assembly, and a portion of the first recess is located inside the electrode lead-out hole.

[0060] Secondly, embodiments of this application provide a battery including a plurality of battery cells and a current-connecting component according to any of the embodiments of the first aspect, wherein the current-connecting component is used to electrically connect at least two battery cells.

[0061] 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.

[0062] Fourthly, embodiments of this application provide a method for manufacturing a single battery cell, comprising: A housing and a terminal body are provided. The housing includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body has an opening at one end away from the cover body. The cover body is provided with an electrode lead-out hole. The terminal body is installed in the electrode lead-out hole. An electrode assembly is provided, the electrode assembly including a first electrode tab disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; Provide a current collection component and connect the current collection component to the first annular portion; The electrode assembly and current collector are installed into the housing, and the current collector and terminal body are connected so that the first tab and the terminal body are electrically connected. Provide a cover plate and attach the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0063] In some embodiments, the terminal body has a first recess, and a connecting portion is formed at the bottom of the first recess. The steps of installing the electrode assembly and the current collector into the housing and connecting the current collector and the terminal body include: installing the electrode assembly and the current collector into the housing and pressing the current collector against the connecting portion; and using external welding equipment to weld the connecting portion and the current collector on the surface of the connecting portion away from the current collector.

[0064] The above solution reduces the thickness of the connection by providing a first recess, which reduces the welding power required to weld the connection to the current collector, decreases heat generation, and lowers the risk of other components being burned. When welding from the outside, the housing can protect the electrode assembly, preventing metal particles generated during welding from sputtering onto the electrode assembly and reducing the risk of short circuits.

[0065] In some embodiments, the terminal body has a second outer surface and a second inner surface disposed opposite each other along a first direction, and a first recess extends from the second outer surface into the first outer surface of the connection portion in a direction facing the electrode assembly. The method of manufacturing a battery cell further includes: providing a sealing plate, placing at least a portion of the sealing plate into the first recess, and welding the sealing plate and the sidewall of the first recess to close the opening of the first recess.

[0066] In the above solution, the sealing plate can protect the connection from the outside, reduce the amount of external impurities entering the first recess, reduce the risk of the connection being damaged by external impurities, and improve the sealing performance of the battery cell.

[0067] Fifthly, embodiments of this application provide a manufacturing system for a single battery cell, comprising: A first providing device is used to provide a housing and a terminal body. The housing includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body has an opening at one end away from the cover. The cover is provided with an electrode lead-out hole. The terminal body is installed in the electrode lead-out hole. A second providing device is used to provide an electrode assembly, the electrode assembly including a first electrode tab disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; The third providing device is used to provide the current collecting component and connect the current collecting component to the first annular portion; An assembly device for mounting electrode assemblies and current collectors into a housing and connecting the current collectors and terminal bodies to make the first tab and the terminal body electrically connected. The fourth providing device is used to provide a cover plate and connect the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0068] Sixthly, embodiments of this application provide another method for manufacturing a single battery cell, including: Provide current collector components and terminal bodies, and connect the current collector components and terminal bodies; An electrode assembly is provided, the electrode assembly including a first electrode tab disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; The current collector is connected to the first annular portion so that the first electrode tab and the terminal body are electrically connected; A housing is provided, comprising a cylindrical body and a cover connected to the cylindrical body, the cylindrical body having an opening at one end away from the cover, and the cover having an electrode lead-out hole; The electrode assembly and current collector are installed into the housing, and the terminal body is installed into the electrode lead-out hole; Provide a cover plate and attach the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0069] In some embodiments, the steps of installing the electrode assembly and current collector into the housing and installing the terminal body into the electrode lead-out hole include: installing the electrode assembly and current collector into the housing, and extending the end of the terminal body away from the electrode assembly through the electrode lead-out hole to the outside of the cover; and forming a flange structure by folding the end of the terminal body away from the electrode assembly outward to fix the terminal body to the cover. This embodiment can simplify the assembly process of the terminal body and the cover.

[0070] In other embodiments, the steps of mounting the electrode assembly and current collector into the housing and mounting the terminal body into the electrode lead-out hole include: mounting the electrode assembly and current collector into the housing, and extending the end of the terminal body away from the electrode assembly through the electrode lead-out hole to the outside of the cover; pressing the end of the terminal body away from the electrode assembly to extend the end outward to form a limiting structure, the limiting structure being used to fix the terminal body to the cover. This embodiment can simplify the assembly process of the terminal body and the cover.

[0071] In a seventh aspect, embodiments of this application provide another battery cell manufacturing system, including: A first providing device is used to provide a current collector and a terminal body, and to connect the current collector and the terminal body; A second providing device is used to provide an electrode assembly, the electrode assembly including a first electrode tab disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; A first assembly device is used to connect a current collector to a first annular portion so that the first electrode tab and the terminal body are electrically connected. The third providing device is used to provide a housing, the housing including a cylindrical body and a cover connected to the cylindrical body, the cylindrical body having an opening at one end away from the cover, and the cover having an electrode lead-out hole; The second assembly device is used to install the electrode assembly and current collector into the housing and to install the terminal body into the electrode lead-out hole; The fourth providing device is used to provide a cover plate and connect the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion. Attached Figure Description

[0072] 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.

[0073] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Explosion diagrams of batteries provided for some embodiments of this application; Figure 3 for Figure 2 The diagram shows the structure of the battery module. Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 6 for Figure 5 A partially enlarged schematic diagram of a single battery cell; Figure 7 This is a schematic diagram of the electrode assembly and current collector of a battery cell according to some embodiments of this application after welding. Figure 8 This is a schematic diagram of the electrode assembly and current collector of a battery cell according to other embodiments of this application after welding; Figure 9 for Figure 6 The enlarged schematic diagram of the battery cell shown in box B; Figure 10 An exploded view of the electrode terminals of a battery cell provided in some embodiments of this application; Figure 11 This is a top view schematic diagram of the electrode terminals of a battery cell provided in some embodiments of this application; Figure 12 Partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application; Figure 13 A partial cross-sectional schematic diagram of a battery cell provided for some embodiments of this application; Figure 14 This is a schematic diagram of the structure of a battery cell connected to a busbar component, provided in some embodiments of this application; Figure 15 A schematic flowchart illustrating a method for manufacturing a single battery cell according to some embodiments of this application; Figure 16 A schematic block diagram of a battery cell manufacturing system provided for some embodiments of this application; Figure 17 A schematic flowchart illustrating a method for manufacturing a battery cell according to other embodiments of this application; Figure 18 A schematic block diagram of a battery cell manufacturing system provided for other embodiments of this application.

[0074] The accompanying drawings are not drawn to scale. Detailed Implementation

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] In this application, "multiple" means two or more (including two).

[0082] 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.

[0083] 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.

[0084] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes 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 electrodes. The positive electrode includes a positive current collector and a positive active material layer, the latter coated on the surface of the current collector. The current collector includes a current-collecting section and a tab; the current-collecting section is coated with the positive active material layer, while the 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, the latter coated on the surface of the current collector. The current-collecting section includes a current-collecting section and a tab; the current-collecting section is coated with the negative active material layer, while the 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.

[0085] The battery cell also includes a housing for accommodating the electrode assembly. The housing has electrode lead-out holes for mounting electrode terminals, which are used to electrically connect to the electrode assembly to enable the charging and discharging of the electrode assembly.

[0086] The electrode assembly includes an electrode generating part and a tab connected to the electrode generating part. Taking the positive electrode as an example, the electrode generating part includes a positive current collector and an active material layer coated on the positive current collector. The electrode assembly generally inputs and outputs current through the tab. In the wound electrode assembly, both the tab and the electrode generating part are multi-turn structures. From the inside to the outside, as the number of turns increases, the circumference of each turn of the electrode generating part and the tab gradually increases. Correspondingly, the internal resistance of each turn also gradually increases.

[0087] The housing includes a cover body disposed opposite to the electrode tabs, and electrode lead-out holes are formed on the cover body. The electrode lead-out holes are usually formed in the middle of the cover body, and correspondingly, the electrode terminals are also installed in the middle of the cover body.

[0088] The inventors noted that, due to the limitation of the electrode lead-out hole position, the electrode terminal can only be connected to the inner ring area of ​​the tab to achieve electrical connection between the electrode terminal and the tab, but cannot be connected to the outer ring area of ​​the tab. This results in a longer conductive path and higher internal resistance between the outer ring area of ​​the electrode generation part and the electrode terminal, affecting the overcurrent capacity and charging efficiency of the battery cell.

[0089] In view of this, the present application provides a technical solution that connects the electrode terminal and the electrode tab by setting a current collector, and connects the current collector to the part of the electrode tab that is outside the electrode lead-out hole, so as to shorten the conductive path between the electrode tab and the electrode terminal, reduce the internal resistance, and improve the overcurrent capacity.

[0090] The technical solutions described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0091] 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.

[0092] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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 51 and a second housing portion 52, which overlap each other, and together define a housing space 53 for housing the individual battery cells. The second housing portion 52 may be a hollow structure with one end open, and the first housing portion 51 may be a plate-like structure, with the first housing portion 51 covering the open side of the second housing portion 52 to form a housing 5 with the housing space 53; alternatively, both the first housing portion 51 and the second housing portion 52 may be hollow structures with one side open, with the open side of the first housing portion 51 covering the open side of the second housing portion 52 to form a housing 5 with the housing space 53. Of course, the first housing portion 51 and the second housing portion 52 can have various shapes, such as cylinders, cuboids, etc.

[0098] To improve the sealing performance after the first housing part 51 and the second housing part 52 are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 51 and the second housing part 52.

[0099] Assuming that the first box part 51 covers the top of the second box part 52, the first box part 51 can also be called the upper box cover, and the second box part 52 can also be called the lower box.

[0100] 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.

[0101] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0102] In some embodiments, such as Figure 3As 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.

[0103] Multiple battery cells 7 in battery module 6 can be electrically connected through busbar components 8 to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbar components, and each busbar component 8 is used to electrically connect at least two battery cells.

[0104] Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 6 for Figure 5 A partially enlarged schematic diagram of a single battery cell is shown.

[0105] like Figures 4 to 6 As shown, this application embodiment provides a battery cell 7, including: an electrode assembly 10, including a first tab 11, the first tab 11 being disposed around the central axis 11 of the electrode assembly 10; a housing 20 for accommodating the electrode assembly 10, the housing 20 including a cylindrical body 21 and a cover 22 connected to the cylindrical body 21, the cylindrical body 21 being disposed around the outer periphery of the electrode assembly 10, the cover 22 having an electrode lead-out hole 221, the central axis A extending along a first direction X and passing through the electrode lead-out hole 221, the first tab 11 including a first annular portion 112, the first annular portion 112 being disposed opposite to the cover 22, and the projection of the first annular portion 112 in the first direction X not overlapping the projection of the electrode lead-out hole 221 in the first direction X; an electrode terminal 30, installed in the electrode lead-out hole 221; and a current collector 40, at least partially located between the cover 22 and the first annular portion 112, the current collector 40 being used to connect the first annular portion 112 and the electrode terminal 30, so that the first tab 11 and the electrode terminal 30 are electrically connected.

[0106] The electrode assembly 10 includes a first electrode, a second electrode, and a separator, the separator being used to separate the first electrode and the second electrode. The first electrode and the second electrode have opposite polarities; in other words, one of the first electrode and the second electrode is the positive electrode, and the other of the first electrode and the second electrode is the negative electrode.

[0107] The first electrode, the second electrode, and the separator are all strip-shaped structures, wound together around the central axis A to form a wound structure. The wound structure can be cylindrical, flat, or other shapes.

[0108] From the external shape of the electrode assembly 10, the electrode assembly 10 includes a main body 12, a first electrode tab 11, and a second electrode tab 13, with the first electrode tab 11 and the second electrode tab 13 protruding from the main body 12. The first electrode tab 11 is the portion of the first electrode sheet that is not coated with an active material layer, and the second electrode tab 13 is the portion of the second electrode sheet that is not coated with an active material layer.

[0109] The first electrode tab 11 and the second electrode tab 13 can extend from the same side of the main body 12, or they can extend from opposite sides respectively. For example, the first electrode tab 11 and the second electrode tab 13 are respectively located on both sides of the main body 12 along the first direction X; in other words, the first electrode tab 11 and the second electrode tab 13 are respectively located at both ends of the electrode assembly 10 along the first direction X. The first electrode tab 11 is located at the end of the electrode assembly 10 facing the cover 22, and the second electrode tab 13 is located at the end of the electrode assembly 10 away from the cover 22.

[0110] Optionally, the first tab 11 is wound multiple times around the central axis A of the electrode assembly 10; in other words, the first tab 11 includes multiple tab layers. After winding, the first tab 11 is generally cylindrical, with gaps between adjacent tab layers. In this embodiment, the first tab 11 can be processed to reduce the gaps between tab layers, facilitating connection between the first tab 11 and other conductive structures. For example, in this embodiment, the first tab 11 can be flattened to gather and aggregate the end regions of the first tab 11 away from the main body 12; the flattening process forms a dense end face at the end of the first tab 11 away from the main body 12, reducing the gaps between tab layers and facilitating connection between the first tab 11 and the current collector 40. Alternatively, in this embodiment, conductive material can be filled between adjacent tab layers to reduce the gaps between tab layers.

[0111] Optionally, the second tab 13 is wound around the central axis A of the electrode assembly 10 multiple times, and the second tab 13 includes multiple tab layers. Exemplarily, the second tab 13 is also flattened to reduce the gaps between the tab layers of the second tab 13.

[0112] The housing 20 is a hollow structure, forming an interior space for accommodating the electrode assembly 10. The shape of the housing 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cylindrical structure, a cylindrical housing can be used; if the electrode assembly 10 is a cuboid structure, a cuboid housing can be used. Optionally, both the electrode assembly 10 and the housing 20 are cylindrical; correspondingly, the cylinder 21 is a cylinder, and the cover 22 is a circular plate structure.

[0113] The cover 22 and the cylinder 21 can be an integrally formed structure, that is, the shell 20 is a one-piece component. Of course, the cover 22 and the cylinder 21 can also be two separate components, which are then connected together by welding, riveting, bonding or other methods.

[0114] The casing 20 is a hollow structure with an opening on one side. Specifically, the cylindrical body 21 has an opening 211 at the end opposite to the cover 22. The battery cell 7 also includes a cover plate 50, which covers the opening 211 of the cylindrical body 21 to close it. The cover plate 50 can have various structures, such as a plate-like structure.

[0115] Electrode lead-out hole 221 extends through cover 22 to allow electrical energy in electrode assembly 10 to be led out to the outside of housing 20. Exemplarily, electrode lead-out hole 221 extends through cover 22 along a first direction X.

[0116] The central axis A is a virtual straight line parallel to the first direction X, which passes through the electrode lead-out hole 221. The central axis A of the electrode assembly 10 may or may not coincide with the axis of the electrode lead-out hole 221.

[0117] Electrode terminal 30 is used to mate with electrode lead-out hole 221 to cover electrode lead-out hole 221. Electrode terminal 30 may or may not extend into electrode lead-out hole 221. Electrode terminal 30 is fixed to cover 22. Electrode terminal 30 may be fixed as a whole to the outside of cover 22, or it may extend into the inside of housing 20 through electrode lead-out hole 221.

[0118] The electrode terminal 30 is used to connect to the busbar component to achieve electrical connection between the battery cells 7.

[0119] The electrode terminal 30 can be insulatedly disposed on the cover 22 or electrically connected to the cover 22. This application embodiment does not limit this, as long as the first electrode 11 and the second electrode 13 are prevented from being connected.

[0120] The casing 20 can be positively charged, negatively charged, or uncharged.

[0121] The first electrode 11 can be either a positive electrode or a negative electrode.

[0122] The current collector 40 can be connected to the first annular portion 112 of the first electrode tab 11 by means of welding, abutment, or bonding, and connected to the electrode terminal 30 by means of welding, abutment, bonding, riveting, etc., thereby realizing the electrical connection between the first electrode tab 11 and the electrode terminal 30.

[0123] The first annular portion 112 is an annular structure arranged around the central axis A. It is located outside the electrode lead-out hole 221 along the second direction, which is the radial direction of the first electrode tab 11.

[0124] In this embodiment, the cover 22 refers to the solid portion, which is disposed opposite to the first annular portion 112 in the first direction X. The cover 22 covers the first annular portion 112 in the first direction X.

[0125] The first electrode tab 11 can be entirely located outside the electrode lead-out hole 221 along the second direction, that is, the first electrode tab 11 only includes the first annular portion 112. Of course, a portion of the first electrode tab 11 can also be disposed opposite to the electrode lead-out hole 221 along the first direction X, that is, the projection of the first electrode tab 11 in the first direction X partially overlaps with the projection of the electrode lead-out hole 221 in the first direction X.

[0126] At least a portion of the current collecting member 40 overlaps with the first annular portion 112 in the first direction X, so that the current collecting member 40 can be connected to the first annular portion 112.

[0127] The first annular portion 112 is located outside the electrode lead-out hole 221 along the second direction, and the radius of each loop of the first annular portion 112 is larger than the radius of the electrode lead-out hole 221.

[0128] In the battery cell 7 of this application embodiment, the first annular portion 112 of the first tab 11 is connected to the electrode terminal 30 by providing a current collector 40. In this way, the current in the electrode assembly 10 can flow to the electrode terminal 30 through the first annular portion 112 and the current collector 40, thereby shortening the conductive path, reducing the internal resistance, and improving the overcurrent capacity and charging efficiency of the battery cell 7.

[0129] The outer ring region of the electrogenerating part of the first electrode corresponds to the first annular part 112. The current in the outer ring region can flow to the electrode terminal 30 through the first annular part 112, thereby shortening the conductive path. The inner ring region of the electrogenerating part of the first electrode has a smaller circumference, so the conductive path between the inner ring region and the first annular part 112 is also relatively small. Therefore, this embodiment can shorten the conductive path and reduce the internal resistance.

[0130] In some embodiments, the central axis A coincides with the axis of the electrode lead-out hole 221.

[0131] This embodiment does not require the central axis A to be completely aligned with the axis of the electrode lead-out hole 221; a process-permissible deviation between the two is allowed.

[0132] In this embodiment, the electrode lead-out hole 221 is generally located in the middle of the cover 22, and correspondingly, the electrode terminal 30 is also installed in the middle of the cover 22. When multiple battery cells 7 are assembled into a group, the positioning accuracy requirements of the electrode terminal 30 can be reduced, and the assembly process can be simplified.

[0133] For example, the axis of the electrode lead-out hole 221 coincides with the axis of the cover 22, and the cover 22 is an annular structure arranged around the axis of the electrode lead-out hole 221.

[0134] For example, the axis of the electrode terminal 30 coincides with the axis of the electrode lead-out hole 221.

[0135] In some embodiments, the cover 22 and the cylinder 21 are integrally formed. This eliminates the need for the connection process between the cover 22 and the cylinder 21. The shell 20 can be formed by a stretching process.

[0136] In some embodiments, the electrode assembly 10 further includes a second tab 13, which is disposed around the central axis A of the electrode assembly 10. The first tab 11 and the second tab 13 are respectively disposed at both ends of the electrode assembly 10 along a first direction X. The cylindrical body 21 is used to connect the second tab 13 and the cover 22 so that the second tab 13 and the cover 22 are electrically connected.

[0137] The cylinder 21 can be directly electrically connected to the second electrode 13, or it can be electrically connected to the second electrode 13 through other components. For example, the second electrode 13 is electrically connected to the cylinder 21 through the cover plate 50.

[0138] The cover 22 and the electrode terminal 30 have different polarities. In this case, one of the cover 22 and the electrode terminal 30 can serve as the positive output terminal of the battery cell 7, and the other can serve as the negative output terminal of the battery cell 7. In this embodiment, the positive and negative output terminals are located on the same side of the battery cell 7, which simplifies the connection process between multiple battery cells 7.

[0139] The electrode lead-out hole 221 in this embodiment is formed after the housing 20 is stretched and formed.

[0140] The inventors attempted to roll-press the open end of the cylinder to fold it inward and form a flange structure, which then pressed against the cover plate to secure it. The inventors then mounted electrode terminals onto the cover plate, using the flange structure and electrode terminals as the two output poles of the battery cell. However, the larger the flange structure, the higher the risk of curling and wrinkling after molding. If curling and wrinkling occur, the surface of the flange structure will be uneven, leading to poor welding when it is welded to external busbar components. Therefore, the size of the flange structure is relatively limited, resulting in insufficient current carrying capacity of the battery cell.

[0141] In this embodiment, an electrode lead-out hole 221 for mounting the electrode terminal 30 is formed on the cover 22 using an opening process, so that the positive and negative output terminals are located at the end of the battery cell 7 away from the opening of the cylinder 21. The cover 22 is formed during the molding process of the shell 20, and the opening of the electrode lead-out hole 221 can also ensure flatness and ensure the connection strength between the cover 22 and the busbar component. At the same time, the flatness of the cover 22 is not constrained by its own size, so the cover 22 can have a larger size, thereby improving the current carrying capacity of the battery cell 7.

[0142] In some embodiments, the second electrode 13 is the negative electrode, and the base material of the housing 20 is steel.

[0143] 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.

[0144] In some embodiments, the first annular portion 112 is welded to the current collector 40 to form a first welded portion W1.

[0145] When assembling the battery cell 7, the first annular portion 112 of the first tab 11 of the electrode assembly 10 can be welded to the current collector 40 first, and then the electrode assembly 10 and the current collector 40 can be placed into the housing 20. Specifically, when welding the first annular portion 112 and the current collector 40, the current collector 40 can be pressed against the flattened end face of the first tab 11 first, and then an external welding device emits a laser on the surface of the current collector 40 away from the first tab 11, and the laser welds the current collector 40 and the first annular portion 112 of the first tab 11 together.

[0146] The shape of the first welded part W1 can be straight, C-shaped, ring-shaped, spiral, V-shaped or other shapes, and this embodiment does not limit it.

[0147] The first welding part W1 can be one or more.

[0148] The first welded part W1 can reduce the contact resistance between the current collector 40 and the first annular part 112, thereby improving the current carrying capacity.

[0149] In some embodiments, the cross section of the first electrode tab 11 perpendicular to the first direction X is annular. The outer radius of the first electrode tab 11 is R, and the minimum distance between the first welded part W1 and the central axis A in the second direction is D, which satisfies: 0.2≤D / R≤0.8, where the second direction is the radial direction of the first electrode tab 11.

[0150] After being flattened, the first electrode tab 11 is roughly cylindrical. The cross-section of the first electrode tab 11 perpendicular to the first direction X is not required to be perfectly circular; a certain degree of deviation is permissible.

[0151] The first welded portion W1 is used to transmit current between the current collector 40 and the first tab 11, and its position directly affects the conductive path of each part of the first tab 11. If D / R < 0.2, the distance between the first welded portion W1 and the outermost tab layer is too large, causing a large difference between the current path between the outermost tab layer and the electrode terminal 30 and the current path between the innermost tab layer and the electrode terminal 30, resulting in uneven current density of the first electrode plate of the electrode assembly and increased internal resistance. Conversely, if D / R > 0.8, the distance between the first welded portion W1 and the innermost tab layer is too large, causing a large difference between the current path between the outermost tab layer and the electrode terminal 30 and the current path between the innermost tab layer and the electrode terminal 30, resulting in uneven current density of the first electrode plate and increased internal resistance.

[0152] In this embodiment, the values ​​of D and R are set to 0.2≤D / R≤0.8, which can reduce the difference in current path between different parts of the first tab 11 and the electrode terminal 30, improve the uniformity of current density of the first electrode of the electrode assembly 10, reduce internal resistance, and improve overcurrent capability.

[0153] Optionally, 0.3 ≤ D / R ≤ 0.7. For example, the value of D / R is 0.3, 0.4, 0.5, 0.6 or 0.7.

[0154] In some embodiments, the total number of turns of the tab layer of the first tab 11 is N1, and the total number of turns of the tab layer connected to the first welding part W1 is N2, and both satisfy: 0.3≤N2 / N1≤0.7.

[0155] The first welded portion W1 connects the N2 loop electrode layers together, allowing the current between the N2 loop electrode layers to flow directly to the current collector 40 through the first welded portion W1 without passing through other loop electrode layers. A ratio of N2 / N1 ≥ 0.3 effectively improves the current carrying capacity and reduces the difference in current paths between different parts of the first loop 11 and the electrode terminal 30. If N2 / N1 > 0.7, the first welded portion W1 will be too large in the radial direction of the electrode assembly 10 on the current collector 40, which will affect the welding between the current collector 40 and the electrode terminal 30.

[0156] Optionally, the value of N2 / N1 can be 0.3, 0.4, 0.5, 0.6 or 0.7.

[0157] Figure 7 This is a schematic diagram of the electrode assembly and current collector of a battery cell according to some embodiments of this application after welding. Figure 8 This is a schematic diagram of the electrode assembly and current collector of a battery cell according to other embodiments of this application after welding.

[0158] like Figure 7 As shown, in some embodiments, the first welded portion W1 is annular and arranged around the central axis.

[0159] The annular first welded part W1 has a large current-carrying area, which can improve the uniformity of the current density of the first electrode, reduce the internal resistance, and improve the current-carrying capacity.

[0160] In some embodiments, the ratio of the size of the first weld portion W1 (i.e., the circumference width of the annular first weld portion W1) to the outer radius of the first tab 11 in the radial direction of the electrode assembly 10 is 0.3-0.7.

[0161] like Figure 8 As shown, in some other embodiments, there are multiple first welding portions W1, and the multiple first welding portions W1 are arranged at intervals along the circumferential Y direction of the first annular portion.

[0162] The first welding part W1 can be a straight structure extending radially along the electrode assembly 10, or it can be a V-shaped mechanism, or of course, it can be other structures.

[0163] Multiple first welding parts W1 can increase the current-carrying area, improve the uniformity of the current density of the first electrode, reduce the internal resistance, and improve the current-carrying capacity.

[0164] Figure 9 for Figure 6 The enlarged schematic diagram of the battery cell shown in box B; Figure 10 This is an exploded view of the electrode terminals of a battery cell provided in some embodiments of this application.

[0165] Please refer to Figure 6 , Figure 9 and Figure 10 In some embodiments, the current collector 40 has a protrusion 41 on the side facing the first electrode 11, and the protrusion 41 is welded to the first annular portion 112 to form a first weld portion W1.

[0166] The current collector 40 has a third inner surface 42 and a third outer surface 43 disposed opposite each other along a first direction X, with the third inner surface 42 facing the first electrode tab 11. A protrusion 41 protrudes relative to the third inner surface 42 toward a first annular portion 112 of the first electrode tab 111. The third inner surface 42 and the third outer surface 43 may be planar. In some examples, except for the protrusion 41, the other parts of the current collector 40 are generally flat plate structures.

[0167] When assembling the current collector 40 and the electrode assembly 10, the protrusion 41 of the current collector 40 is first pressed against the first annular portion 112, and then the protrusion 41 and the first annular portion 112 are welded together. The protrusion 41 can fit better with the first annular portion 112, reducing the risk of poor welding.

[0168] In some embodiments, the protrusion 41 can press against and embed into the first annular portion 112, and the third inner surface 42 abuts against the end face of the first annular portion 112. In this way, some current can also be transmitted through the mating point between the third inner surface 42 and the end face of the first annular portion 112, thereby improving the current carrying capacity.

[0169] In some embodiments, the current collecting member 40 forms a third recess 44 at a position corresponding to the protrusion 41. The third recess 44 is recessed relative to the third outer surface 43 in a direction facing the first annular portion 112. A transition portion is formed between the bottom surface of the third recess 44 and the top surface of the protrusion 41. The transition portion is welded to the first annular portion 112 to form a first weld portion W1.

[0170] By providing the third recess 44, the thickness of the adapter can be reduced, thereby reducing the welding power required for welding the adapter to the first annular portion 112, reducing heat generation, and lowering the risk of the electrode assembly 10 being burned.

[0171] The first welded part W1 is formed by welding, and its surface is uneven. In this embodiment, by providing a third recess 44, the surface of the first welded part W1 can be recessed relative to the third outer surface 43, so as to avoid the first welded part W1 from other components (such as electrode terminals 30).

[0172] In some embodiments, a retaining piece (not shown) may be provided within the third recess 44. The retaining piece is used to cover the first welded portion W1 to fix residual metal particles on the first welded portion W1, reducing the risk of metal particles falling into the electrode assembly 10 and causing a short circuit. The retaining piece may be an insulating patch, an insulating adhesive layer, or other structures.

[0173] The first electrode tab 11 also includes a second annular portion 111, which is disposed opposite to the electrode lead-out hole 221 along the first direction X, and the first annular portion 112 surrounds the outside of the second annular portion 111. At least a portion of the second annular portion 111 abuts against the current collector 40.

[0174] The second annular portion 111 being positioned opposite the electrode lead-out hole 221 along the first direction X means that the projection of the second annular portion 111 along the first direction X lies within the projection of the electrode lead-out hole 221 along the first direction X, and the outline of the projection of the second annular portion 111 along the first direction X coincides with the outline of the projection of the electrode lead-out hole 221 along the first direction X. For example, the second annular portion 111 is positioned around the central axis A.

[0175] The first annular portion 112 is connected to the second annular portion 111, and the first annular portion 112 is an annular structure surrounding the outside of the second annular portion 111. The outline of the electrode lead-out hole 221 projected onto the first electrode tab 11 along the first direction X can be considered to coincide with the outline of the boundary line between the second annular portion 111 and the first annular portion 112.

[0176] At least a portion of the second annular portion 111 abuts against the third inner surface 42 of the current collector 40. A portion of the current can be transmitted to the current collector 40 through the point where the second annular portion 111 abuts against the current collector 40.

[0177] This embodiment improves the flow capacity by providing a second annular portion 111. The second annular portion 111 can also support the first annular portion 112 radially, thereby reducing the risk of the first annular portion 112 being crushed and deformed when welding the first annular portion 112 and the current collecting member 40, and improving the welding stability of the first annular portion 112 and the current collecting member 40.

[0178] In some embodiments, the electrode terminal 30 includes a terminal body 34 having a first recess 31. A connecting portion 32 is formed at the bottom of the first recess 31 on the terminal body 34, and the connecting portion 32 is welded to the current collector 40 to form a second welding portion W2.

[0179] The connecting portion 32 has a first inner surface 321 and a first outer surface 322 disposed opposite to each other, with the first inner surface 321 facing the flow collecting member 40. Optionally, both the first inner surface 321 and the first outer surface 322 are planar.

[0180] The first recess 31 can be recessed from the side of the electrode terminal 30 away from the electrode assembly 10 along the direction facing the electrode assembly 10, or it can be recessed from the side of the electrode terminal 30 facing the electrode assembly 10 along the direction away from the electrode assembly 10. In other words, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed along a first direction, and the first recess 31 can be formed either on the second outer surface 344 or on the second inner surface 345.

[0181] The projection of the connecting portion 32 along the first direction X lies within the projection of the electrode lead-out hole 221 along the first direction X. In the first direction X, the current collector 40 is located between the connecting portion 32 and the first electrode tab 11. A portion of the current collector 40 overlaps with the connecting portion 32 in the first direction X to achieve welding between the connecting portion 32 and the current collector 40.

[0182] When the electrode assembly 10 and the current collector 40 are installed into the housing 20 through the opening of the cylinder 21, and the current collector 40 is pressed against the connecting part 32, the external welding equipment can weld the connecting part 32 and the current collector 40 from the side of the connecting part 32 away from the current collector 40 to form a second welded part W2.

[0183] In this embodiment, the thickness of the connecting part 32 is reduced by providing the first recess 31. This reduces the welding power required to weld the connecting part 32 to the current collector 40, reduces heat generation, and lowers the risk of other components (such as the first insulating component 60 described later) being burned.

[0184] In some embodiments, the thickness of the connecting portion 32 is 0.5mm-10mm.

[0185] In some embodiments, in the thickness direction of the connecting portion 32, the second weld portion W2 extends from the first outer surface 322 to the current collector 40, and the second weld portion W2 is spaced at a predetermined distance from the surface of the current collector 40 opposite to the connecting portion 32, so as to avoid the current collector 40 being melted through.

[0186] In some embodiments, the connection portion 32 is provided with a stress relief structure, which is used to release stress when welding the connection portion 32 and the current collector 40.

[0187] During the welding process, the connection part 32 is affected by welding stress. This application releases stress by setting a stress relief structure, thereby reducing the risk of deformation and cracking of the connection part 32 during welding and ensuring the connection strength between the connection part 32 and the current collecting member 40.

[0188] For example, the stress relief structure can be a hole, a slot, or other structure.

[0189] In some embodiments, the connecting portion 32 is provided with a first through hole 323, which is used to connect the space on the side of the connecting portion 32 away from the electrode assembly 10 to the internal space of the housing 20.

[0190] The first through hole 323 extends through the connecting portion 32 along its thickness direction. There may be one or more first through holes 323.

[0191] When welding the connection 32 and the current collecting member 40, the first through hole 323 can release welding stress and reduce the risk of the connection 32 breaking.

[0192] During the molding process of the battery cell 7, the first through hole 323 can be used in multiple molding processes. For example, the first through hole 323 can be applied to the liquid injection process, the formation process, or other processes.

[0193] Specifically, the first through hole 323 is used to inject electrolyte into the internal space of the housing 20. When electrolyte injection is required, the injection head of the injection device presses against the connection 32, and then the injection head injects electrolyte into the housing 20 through the first through hole 323.

[0194] During the formation process of the battery cell 7, gas is generated inside the casing 20. The first through hole 323 can also be used to connect with an external negative pressure device to extract the gas inside the casing 20.

[0195] In some embodiments, the axis of the first through hole 323 coincides with the axis of the electrode lead-out hole 221.

[0196] In some embodiments, the current collector 40 is provided with a second through hole 45, which is configured to be opposite to the first through hole 323 so that the electrolyte can flow into the internal space of the housing 20 through the second through hole 45.

[0197] The projection of the first through hole 323 in the first direction X at least partially overlaps with the projection of the second through hole 45 in the first direction X. This embodiment does not limit the diameter of the second through hole 45; it can be greater than, equal to, or smaller than the diameter of the first through hole 323.

[0198] In this embodiment, by providing a second through hole 45 on the current collector 40 that is opposite to the first through hole 323, the current collector 40 reduces the obstruction of the electrolyte by the current collector 40 during the electrolyte injection process, so that the electrolyte can flow smoothly into the housing 20 and improve the wetting efficiency of the electrode assembly 10.

[0199] In some embodiments, the projection of the first through hole 323 along the first direction X lies within the projection of the second through hole 45 along the first direction X. This embodiment can prevent the current collector 40 from blocking the first through hole 323 in the first direction X, allowing the electrolyte to flow smoothly into the housing 20.

[0200] The first through hole 323 and the second through hole 45 are coaxially arranged, and the diameter of the second through hole 45 can be greater than or equal to the diameter of the first through hole 323.

[0201] In some embodiments, the electrode assembly 10 is a wound structure, and the electrode assembly 10 has a third through hole 14 at the winding center. The third through hole 14 penetrates the electrode assembly 10 along the first direction X. The third through hole 14 is arranged opposite to the first through hole 323 and the second through hole 45 along the first direction X, so that the electrolyte can flow into the interior of the electrode assembly 10 through the third through hole 14.

[0202] The electrode assembly 10 is manufactured by winding a first electrode, a second electrode, and a spacer onto a winding tool. After winding, the winding tool is removed from the electrode assembly 10. After the winding tool is removed, a third through hole 14 is formed in the middle of the electrode assembly 10.

[0203] The axis of the third through hole 14 coincides with the central axis A of the electrode assembly 10. The third through hole 14 passes through the first electrode tab 11, the main body portion 12, and the second electrode tab 13 along the first direction X. The second annular portion 111 of the first electrode tab 11 is a ring-shaped structure surrounding the outside of the third through hole 14, and the first annular portion 112 is a ring-shaped structure surrounding the outside of the second annular portion 111.

[0204] During the electrolyte injection process, the electrolyte can flow into the third through hole 14 through the first through hole 323 and the second through hole 45. The electrolyte flowing into the third through hole 14 can wet the electrode assembly 10 from the inside, thereby improving the wetting efficiency of the electrode assembly 10.

[0205] In some embodiments, the projection of the second through hole 45 along the first direction X lies within the projection of the third through hole 14 along the first direction X. This reduces the obstruction of the second through hole 45 by the first electrode tab 11, allowing the electrolyte to flow smoothly into the third through hole 14.

[0206] In some embodiments, the first through hole 323, the second through hole 45, and the third through hole 14 are coaxially arranged. The diameter of the third through hole 14 may be greater than or equal to the diameter of the second through hole 45.

[0207] In some embodiments, the connecting portion 32 includes a groove 324, the bottom wall of which is formed with a second welding portion W2. The groove 324 is configured to be recessed from the first outer surface 322 of the connecting portion 32 in a direction facing the electrode assembly 10, so that a gap is formed between the first outer surface 322 and the bottom wall of the groove 324.

[0208] The groove 324 is recessed relative to the first outer surface 322 in the direction facing the flow collecting member 40. In this embodiment, by forming the groove 324 on the connecting portion 32, a stepped structure is formed on the connecting portion 32.

[0209] The portion between the bottom wall of the groove 324 and the first inner surface 321 is used for welding to the current collector 40 to form a second welded portion W2. A first through hole 323 extends from the bottom wall of the groove 324 to the first inner surface 321 to allow the connecting portion 32 to pass through.

[0210] During the production of a battery cell, external equipment needs to cooperate with the connecting part 32. The surface of the second welding part W2 is uneven, and if the external equipment is pressed onto the second welding part W2, the external equipment is easily damaged by the second welding part W2. In this embodiment, a groove 324 is provided to form a gap between the first outer surface 322 and the bottom wall 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 second welding part W2 and reducing the risk of the external equipment being damaged.

[0211] External equipment may be liquid injection equipment, air extraction equipment, welding equipment, or equipment used for individual battery cells.

[0212] For example, during electrolyte injection, the injection head presses against the first outer surface 322. The first outer surface 322 can support the injection head and cooperate with the injection head to achieve a seal, reducing the risk of electrolyte leakage to the outside of the battery cell 7.

[0213] Figure 11 This is a top view of the electrode terminals of a battery cell provided in some embodiments of this application.

[0214] Please refer to the above as well. Figures 9 to 11 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 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 along the first direction and are used to clamp a part of the cover 22.

[0215] The first limiting part 342 is provided on the outer side of the cover 22 along the first direction, meaning that the first limiting part 342 is provided on the side of the cover 22 away from the electrode assembly in the first direction; the second limiting part 343 is provided on the inner side of the cover 22 along the first direction, meaning that the second limiting part 343 is provided on the side of the cover 22 facing the electrode assembly in the first direction.

[0216] In the first direction, 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 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.

[0217] 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.

[0218] 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.

[0219] In some embodiments, the battery cell 7 further includes a first insulating member 60 and a second insulating member 70. At least a portion of the first insulating member 60 is disposed between the first limiting portion 342 and the cover 22, and at least a portion of the second insulating member 70 is disposed between the second limiting portion 343 and the cover 22. The first insulating member 60 and the second insulating member 70 are used to insulate and isolate the terminal body 34 from the cover 22.

[0220] Both the first insulating member 60 and the second insulating member 70 are annular structures arranged around the columnar portion 341.

[0221] The first insulating member 60 can insulate and isolate the first limiting part 342 from the cover 22, and the second insulating member 70 can insulate and isolate the second limiting part 343 from the cover 22.

[0222] In some embodiments, one of the first insulating member 60 and the second insulating member 70 separates the columnar portion 341 and the cover 22. For example, a portion of the first insulating member 60 extends into the electrode lead-out hole 221 to separate the hole wall of the electrode lead-out hole 221 from the columnar portion 341.

[0223] In some embodiments, the first insulating member 60 and the second insulating member 70 are integrally formed. Alternatively, in other embodiments, the first insulating member 60 and the second insulating member 70 are provided separately and abut against each other.

[0224] In some embodiments, one of the first insulating member 60 and the second insulating member 70 is used to seal the electrode lead-out hole. In some examples, the first limiting portion 342 and the cover 22 compress the first insulating member 60, compressing and sealing the electrode lead-out hole 221 from the outside. In other examples, the second limiting portion 343 and the cover 22 compress the second insulating member 70, compressing and sealing the electrode lead-out hole 221 from the inside.

[0225] In some embodiments, the battery cell 7 further includes a sealing ring 80, which is fitted onto the columnar portion 341 and used to seal the electrode lead-out hole 221. Optionally, a portion of the sealing ring 80 extends into the electrode lead-out hole 221 to separate the hole wall of the electrode lead-out hole 221 from the columnar portion 341.

[0226] In some embodiments, the outer periphery of the first limiting portion 342 is provided with a plurality of protrusions 342a, and the plurality of protrusions 342a are arranged at intervals along the circumferential direction of the columnar portion 341.

[0227] Optionally, the multiple protrusions 342a can be arranged at equal intervals along the circumference of the columnar portion 341.

[0228] The first limiting part 342 is a flange structure formed by folding the end of the terminal body 34 away from the electrode assembly outward.

[0229] Before the terminal body 34 is assembled to the housing, the first limiting portion 342 of the terminal body 34 is generally cylindrical and located at the upper end of the columnar portion 341, with the outer side wall of the first limiting portion 342 flush with the outer side wall of the columnar portion 341. When assembling the terminal body 34 and the housing, the first limiting portion 342 is passed through the electrode lead-out hole 221, and then the first limiting portion 342 is folded outward by pressing it, and the terminal body 34 is riveted to the cover 22.

[0230] Before the first limiting portion 342 is folded over, a plurality of spaced-apart groove structures 342b are formed on the upper end of the first limiting portion 342; after the first limiting portion 342 is folded over, a plurality of spaced-apart protrusion structures 342a are formed along the circumference of the columnar portion 341, and the groove structures 342b are between adjacent protrusion structures 342a. In this embodiment, by providing groove structures 342b and protrusion structures 342a, the difficulty of folding the first limiting portion 342 is reduced, and the stress concentration on the first limiting portion 342 is reduced.

[0231] In some embodiments, the second limiting portion 343 is a limiting structure formed by pressing the end of the terminal body 34 facing the electrode assembly to extend the end of the terminal body 34 facing the electrode assembly outward. When assembling the cover 22 and the terminal body 34, an external device can press the end of the terminal body 34 facing the electrode assembly, and the end of the terminal body 34 facing the electrode assembly extends outward under pressure to form the protruding second limiting portion 343.

[0232] In some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed opposite to each other in a first direction, and a first recess 31 is recessed from the second outer surface 344 in a direction facing the electrode assembly 10 to the first outer surface 322 of the connection portion 32.

[0233] In some embodiments, the electrode terminal 30 includes a sealing plate 33, which is connected to the terminal body 34 and closes the opening of the first recess 31.

[0234] 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.

[0235] The sealing plate 33 can protect the connection part 32 from the outside, reduce the external impurities entering the first recess 31, reduce the risk of the connection part 32 being damaged by external impurities, and improve the sealing performance of the battery cell 7.

[0236] In addition, the sealing plate 33 also serves to seal the first through hole 323. After the battery cell 7 is formed, the sealing plate 33 can reduce the risk of electrolyte leakage through the first through hole 323 and the first recess 31, thereby improving the sealing performance.

[0237] 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.

[0238] The first recess 31 is a stepped recess that is larger on the outside and smaller on the inside.

[0239] When assembling the sealing plate 33, the stepped surface 311 can support and position the sealing plate 33, thereby simplifying the assembly process. At least a portion of the sealing plate 33 is accommodated in the first recess 31, which can reduce the overall size of the electrode terminal 30 in the first direction, reduce the space occupied by the electrode terminal 30, and improve the energy density.

[0240] 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.

[0241] In some embodiments, a gap is provided between the sealing plate 33 and the connecting portion 32, the gap being used to avoid the second welding portion W2.

[0242] The surface of the second welded part W2 is uneven. If the sealing plate 33 presses against the second welded part W2, 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 connecting part 32 to avoid direct contact between the sealing plate 33 and the second welded part W2, thereby reducing the wobble of the sealing plate 33 during assembly and ensuring the sealing effect.

[0243] In some examples, the first recess 31 has a stepped structure, such that the sealing plate 33 abuts against the stepped surface 311 to form a gap between the sealing plate 33 and the connecting portion 32. In other examples, the connecting portion 32 may also be provided with a stepped structure, such that the sealing plate 33 can abut against the connecting portion 32, and the groove 324 on the connecting portion 32 forms a gap between the sealing plate 33 and the connecting portion 32.

[0244] In some embodiments, the connecting portion 32 is disposed at one end of the terminal body 34 facing the electrode assembly 10, and the first inner surface 321 and the second inner surface 345 of the connecting portion 32 are flush.

[0245] 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 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 40 having a flat plate structure. In this embodiment, the connecting portion 32 and the current collector 40 can be fitted together simply by attaching the third outer surface 43 of the current collector 40 to the second inner surface 345, so as to facilitate the welding of the connecting portion 32 and the current collector 40.

[0246] Figure 12 This is a partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application.

[0247] like Figure 12 As shown, in some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed along a first direction X, and a first recess 31 recesses from the second outer surface 344 in a direction facing the electrode assembly 10 to the first outer surface 322 of the connecting portion 32. The terminal body 34 also includes a second recess 35, which recesses from the second inner surface 345 in a direction away from the electrode assembly to the first inner surface 321 of the connecting portion 32.

[0248] This embodiment of the application reduces the thickness of the connecting portion 32 by simultaneously providing a first recess 31 and a second recess 35. This reduces the depth requirement of the first recess 31 and simplifies the molding process. Providing the second recess 35 also increases the internal space of the battery cell 7, thereby improving energy density.

[0249] In some embodiments, the current collector 40 includes a terminal connection portion 46 and a tab connection portion 47 surrounding the outside of the terminal connection portion 46. The terminal connection portion 46 protrudes from the tab connection portion 47 and extends into the second recess 35, such that the top of the terminal connection portion 46 abuts against the first inner surface 321 of the connection portion 32.

[0250] The electrode connecting portion 47 is located between the cover 22 and the first electrode 11, welded to the first annular portion, and forms the first welded portion W1. Optionally, the electrode connecting portion 47 may be a circular flat plate structure.

[0251] In some embodiments, the current collector 40 has a fourth recess 48 at a position corresponding to the terminal connection portion 46. The fourth recess 48 is recessed relative to the surface of the electrode connection portion 47 facing the first electrode 11. The fourth recess 48 can reduce the space occupied by the terminal connection portion 46 and reduce the weight of the current collector 40. Exemplarily, the terminal connection portion 46 and the fourth recess 48 are formed by stamping the current collector 40.

[0252] Figure 13 This is a partial cross-sectional schematic diagram of a battery cell provided for some embodiments of this application.

[0253] like Figure 13 As shown, in some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed along a first direction X, and a first recess 31 is recessed from the second inner surface 345 in a direction away from the electrode assembly to the first inner surface 321 of the connection portion 32.

[0254] In this embodiment, the first recess 31 is disposed on the inner side of the terminal body 34, which ensures the flatness and area of ​​the second outer surface 344, facilitating the connection between the terminal body 34 and external busbar components. Providing the first recess 31 on the inner side of the terminal body 34 also increases the internal space of the battery cell 7, thereby improving energy density.

[0255] In some embodiments, the current collector 40 includes a terminal connection portion 46 and an electrode connection portion 47 surrounding the outside of the terminal connection portion 46. The terminal connection portion 46 protrudes from the electrode connection portion 47 and extends into the first recess 31, such that the top of the terminal connection portion 46 abuts against the first inner surface 321 of the connection portion 32.

[0256] The electrode connecting portion 47 is located between the cover 22 and the first electrode 11, welded to the first annular portion, and forms the first welded portion W1. Optionally, the electrode connecting portion 47 may be a circular flat plate structure.

[0257] In some embodiments, the current collector 40 has a fourth recess 48 at a position corresponding to the terminal connection portion 46. The fourth recess 48 is recessed relative to the surface of the electrode connection portion 47 facing the first electrode 11. The fourth recess 48 can reduce the space occupied by the terminal connection portion 46 and reduce the weight of the current collector 40. Exemplarily, the terminal connection portion 46 and the fourth recess 48 are formed by stamping the current collector 40.

[0258] Figure 14 This is a schematic diagram of the structure of a battery cell connected to a busbar component, provided in some embodiments of this application.

[0259] like Figure 14 As shown, in some embodiments, the terminal body 34 has a second outer surface 344 and a second inner surface 345 disposed opposite each other along a first direction, and a first recess 31 is recessed from the second outer surface 344 along the direction facing the electrode assembly 10 to the first outer surface 322 of the connecting portion 32. The electrode terminal 30 also includes a sealing plate 33, which is connected to the terminal body 34 and closes the opening of the first recess 31. The sealing plate 33 is used to weld to the battery's busbar component 8 and form a third weld portion W3.

[0260] In the battery, the battery cells 7 are electrically connected through the busbar component 8. The third welded part W3 can reduce the contact resistance between the sealing plate 33 and the busbar component 8, thereby improving the current carrying capacity.

[0261] Optionally, in the battery, the busbar 8 connects the sealing plate 33 of one battery cell 7 and the cover of another battery cell to connect the two battery cells in series.

[0262] In some embodiments, at least a portion of the sealing plate 33 protrudes from the second outer surface 344 of the terminal body 34.

[0263] When it is necessary to weld the manifold 8 and the sealing plate 33, first attach the manifold 8 to the upper surface of the sealing plate 33 (i.e., the outer surface of the sealing plate 33 facing away from the connection part), and then weld the manifold 8 and the sealing plate 33.

[0264] At least a portion of the sealing plate 33 protrudes from the second outer surface 344 to avoid the second outer surface 344 interfering with the fit between the sealing plate 33 and the manifold 8, thus ensuring a tight fit between the manifold 8 and the sealing plate 33.

[0265] In some embodiments, at least a portion of the sealing plate 33 is accommodated in the first recess 31, and the sidewall of the first recess 31 is provided with a stepped surface for supporting the sealing plate 33. The sealing plate 33 is welded to the sidewall of the first recess 31 to form a fourth welded portion W4, which is used to seal the opening of the first recess 31.

[0266] The fourth welding part W4 surrounds the outer periphery of the sealing plate 33 to seal the gap between the sealing plate 33 and the side wall of the first recess 31, thereby improving the sealing performance of the battery cell 7.

[0267] In some embodiments, in the direction away from the connection, the fourth welded part W4 does not extend beyond the upper surface of the sealing plate 33, so as to avoid interference between the fourth welded part W4 and the busbar component 8.

[0268] In some embodiments, the third welded part W3 is entirely located within the area enclosed by the fourth welded part W4.

[0269] The fourth welded part W4 surrounds the outside of the third welded part W3 and is spaced at a predetermined distance from the third welded part W3.

[0270] This embodiment can avoid the intersection of the third welded part W3 and the fourth welded part W4 when welding the busbar component 8 and the sealing plate 33, thereby reducing the risk of incomplete welding.

[0271] Figure 15 This is a schematic flowchart illustrating a method for manufacturing a battery cell according to some embodiments of this application.

[0272] like Figure 15 As shown, the method for manufacturing a single battery cell according to an embodiment of this application includes: S110. Provide a housing and a terminal body. The housing includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body has an opening at one end away from the cover. The cover is provided with an electrode lead-out hole. The terminal body is installed in the electrode lead-out hole. S120. An electrode assembly is provided, the electrode assembly including a first electrode tab, the first electrode tab being disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; S130. Provide a current collection component and connect the current collection component to the first annular portion; S140. Install the electrode assembly and current collector into the housing, and connect the current collector and the terminal body so that the first electrode tab and the terminal body are electrically connected. S150. Provide a cover plate and attach the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0273] In some embodiments, the terminal body has a first recess, and a connecting portion is formed at the bottom of the first recess.

[0274] Step S140 includes: S141. Install the electrode assembly and current collector into the housing, and press the current collector against the connection part; S142. External welding equipment acts on the surface of the connection part away from the current collector to weld the connection part and the current collector.

[0275] External welding equipment welds the connector and the current collector to form a second welded part. In this embodiment, the thickness of the connector is reduced by providing a first recess, which reduces the welding power required to weld the connector to the current collector, decreases heat generation, and lowers the risk of other components being burned. When welding from the outside, the housing protects the electrode assembly, preventing metal particles generated during welding from sputtering onto the electrode assembly and reducing the risk of short circuits.

[0276] In some embodiments, the terminal body has a second outer surface and a second inner surface disposed opposite each other along a first direction, and a first recess extends from the second outer surface into the first outer surface of the connection portion along a direction facing the electrode assembly. The method of manufacturing a battery cell further includes step S160: providing a sealing plate, placing at least a portion of the sealing plate into the first recess, and welding the sealing plate and the sidewall of the first recess to close the opening of the first recess.

[0277] The sealing plate can protect the connection from the outside, reduce the amount of external impurities entering the first recess, reduce the risk of the connection being damaged by external impurities, and improve the sealing performance of the battery cell.

[0278] It should be noted that the relevant structure of the battery cell manufactured by the above-described battery cell manufacturing method can be found in the battery cells provided in the above embodiments.

[0279] When assembling battery cells based on the above-described battery cell manufacturing method, the steps do not necessarily need to be performed sequentially. That is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously. For example, steps S110 and S120 can be performed in any order and can be performed simultaneously.

[0280] Figure 16 This is a schematic block diagram of a battery cell manufacturing system provided for some embodiments of this application.

[0281] like Figure 16 As shown, the battery cell manufacturing system 91 of this application embodiment includes: A first providing device 911 is used to provide a housing and a terminal body. The housing includes a cylindrical body and a cover connected to the cylindrical body. The cylindrical body has an opening at one end away from the cover. The cover is provided with an electrode lead-out hole. The terminal body is installed in the electrode lead-out hole. The second providing device 912 is used to provide an electrode assembly, the electrode assembly including a first electrode tab, the first electrode tab being disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; The third providing device 913 is used to provide the current collecting component and connect the current collecting component to the first annular portion; Assembly device 914 is used to install electrode assembly and current collector into housing and connect current collector and terminal body so that first electrode tab and terminal body are electrically connected. The fourth providing device 915 is used to provide a cover plate and connect the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0282] The relevant structure of the battery cell manufactured by the above-described manufacturing system 91 can be found in the battery cells provided in the above embodiments.

[0283] Figure 17 This is a schematic flowchart illustrating a method for manufacturing a battery cell according to other embodiments of this application.

[0284] like Figure 17 As shown, the method for manufacturing a single battery cell according to an embodiment of this application includes: S210, Provide a current collector and a terminal body, and connect the current collector and the terminal body; S220. An electrode assembly is provided, the electrode assembly including a first electrode tab, the first electrode tab being disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; S230. Connect the current collector to the first annular portion so that the first electrode and the terminal body are electrically connected; S240. A housing is provided, the housing including a cylindrical body and a cover connected to the cylindrical body, the cylindrical body having an opening at one end away from the cover, and the cover having an electrode lead-out hole; S250. Install the electrode assembly and current collector into the housing, and install the terminal body into the electrode lead-out hole; S260. Provide a cover plate and attach the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0285] In some embodiments, step S250 includes: S251. Install the electrode assembly and current collector into the housing, and make the end of the terminal body away from the electrode assembly extend to the outside of the cover through the electrode lead-out hole. S252, A flange structure formed by folding the end of the terminal body away from the electrode assembly outward to install the terminal body into the electrode lead-out hole and fix it to the cover.

[0286] The flange structure formed by folding the terminal body outward can be the first limiting part.

[0287] In this embodiment, the terminal body can be fixed to the cover plate by folding the end of the terminal body, thereby simplifying the assembly process of the terminal body and the cover.

[0288] In other embodiments, step S250 includes: S253. Install the electrode assembly and current collector into the housing, and make the end of the terminal body away from the electrode assembly extend to the outside of the cover through the electrode lead-out hole. S254. The end of the terminal body away from the electrode assembly is pressed to extend the end outward to form a limiting structure for fixing the terminal body to the cover.

[0289] The limiting structure formed by extrusion can be the first limiting part.

[0290] In this embodiment, the terminal body can be fixed to the cover plate by pressing the end of the terminal body, thereby simplifying the assembly process of the terminal body and the cover.

[0291] It should be noted that the relevant structure of the battery cell manufactured by the above-described battery cell manufacturing method can be found in the battery cells provided in the above embodiments.

[0292] In the battery cell manufactured by the above-described battery cell manufacturing method, the first recess and the sealing plate can be omitted.

[0293] When assembling battery cells based on the above-described battery cell manufacturing method, the steps do not necessarily need to be performed sequentially. That is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously. For example, steps S210 and S220 can be performed concurrently without any order.

[0294] Figure 18 A schematic block diagram of a battery cell manufacturing system provided for other embodiments of this application.

[0295] like Figure 18 As shown, the battery cell manufacturing system 92 of this application embodiment includes: The first providing device 921 is used to provide a current collector and a terminal body, and to connect the current collector and the terminal body; The second providing device 922 is used to provide an electrode assembly, the electrode assembly including a first electrode tab, the first electrode tab being disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; The first assembly device 923 is used to connect the current collector to the first annular portion so that the first electrode and the terminal body are electrically connected. The third providing device 924 is used to provide a housing, the housing including a cylindrical body and a cover connected to the cylindrical body, the cylindrical body having an opening at one end away from the cover, and the cover having an electrode lead-out hole; The second assembly device 925 installs the electrode assembly and current collector into the housing and installs the terminal body into the electrode lead-out hole; The fourth providing device 926 provides a cover plate and connects the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along the first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction. At least a portion of the current collecting member is located between the cover and the first annular portion.

[0296] The relevant structure of the battery cell manufactured by the above-described manufacturing system 92 can be found in the battery cells provided in the above embodiments.

[0297] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0298] 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, comprising: an electrode assembly including a first tab disposed around a central axis of the electrode assembly; a case for accommodating the electrode assembly, the case including a barrel disposed around an outer periphery of the electrode assembly and a lid connected to the barrel, the barrel and the lid being formed in one piece, the barrel having an opening at an end thereof facing away from the lid, the lid being provided with an electrode lead-out hole through which the central axis extends in a first direction, the first tab including a first annular portion disposed opposite the lid, and a projection of the first annular portion in the first direction not overlapping a projection of the electrode lead-out hole in the first direction; a cover plate for closing the opening; an electrode terminal mounted to the electrode lead-out hole; and a current collecting member at least partially located between the lid and the first annular portion, the current collecting member connecting the first annular portion and the electrode terminal such that the first tab and the electrode terminal are electrically connected. The central axis coincides with an axis of the electrode lead-out hole. The first annular portion is welded to the current collecting member and forms a first weld. A cross section of the first tab perpendicular to the first direction is circular annular; An outer radius of the first tab is R, and a minimum distance of the first weld from the central axis in a second direction is D, both satisfying 0.2≤D / R≤0.8, wherein the second direction is a radial direction of the first tab. The first weld is annular and disposed around the central axis; or The first weld is a plurality of first welds spaced apart along a circumferential direction of the first annular portion.

2. The battery cell of claim 1, wherein, The current collecting member has a protrusion on a side facing the first tab, the protrusion being welded to the first annular portion to form the first weld.

3. The battery cell of claim 1 or 2, wherein, The current collecting member forms a third recess at a position corresponding to the protrusion, a transition portion between a bottom surface of the third recess and a top surface of the protrusion being welded to the first annular portion and forming the first weld.

4. The battery cell of claim 3, wherein, The first tab further includes a second annular portion disposed opposite the electrode lead-out hole in the first direction, and the first annular portion is disposed outside the second annular portion; At least a portion of the second annular portion abuts the current collecting member.

5. The battery cell of claim 3 or 4, wherein, The electrode terminal includes a terminal body having a first recess; The terminal body forms a connecting portion at a bottom of the first recess, the connecting portion being welded to the current collecting member and forming a second weld.

6. The battery cell of any one of claims 3-5, wherein, The connecting portion is provided with a stress release structure for releasing stress when the connecting portion and the current collecting member are welded.

7. The battery cell of claim 6, wherein, The connecting portion is provided with a first through hole for connecting a space on a side of the connecting portion facing away from the electrode assembly to an internal space of the case.

8. The battery cell of any one of claims 1-7, wherein, The first through hole is used for injecting electrolyte into the internal space of the case. ​ 9. The battery cell of any one of claims 1-8, wherein, ​ ​ 10. The battery cell of claim 9, wherein, ​ 11. The battery cell of claim 9 or 10, wherein, ​ 12. The battery cell of claim 11, wherein, ​ 13. The battery cell of claim 11 or 12, wherein, The current collecting member is provided with a second through hole, which is configured to be opposite to the first through hole so that the electrolyte can flow into the internal space of the housing through the second through hole.

14. The battery cell of claim 13, wherein, The projection of the first through hole along the first direction lies within the projection of the second through hole along the first direction.

15. The battery cell of claim 13 or 14, wherein, The electrode assembly has a wound structure, and the electrode assembly has a third through hole at the center of the winding. The third through hole penetrates the electrode assembly along the first direction. The third through hole is arranged opposite to the first through hole and the second through hole along the first direction, so that the electrolyte can flow into the interior of the electrode assembly through the third through hole.

16. The battery cell of claim 15, wherein, The projection of the second through hole along the first direction lies within the projection of the third through hole along the first direction.

17. The battery cell of any one of claims 9-16, wherein, A portion of the first recess is located within the electrode lead-out hole.

18. The battery cell of any one of claims 9-17, wherein, The connecting portion includes a groove, the bottom wall of which forms the second welding portion. The groove is configured to be recessed from the first outer surface of the connecting portion in a direction facing the electrode assembly, such that a gap is formed between the first outer surface and the bottom wall of the groove.

19. The battery cell of any one of claims 9-18, wherein, The terminal body includes a columnar portion, a first limiting portion, and a second limiting portion. At least a portion of the columnar portion is located inside the electrode lead-out hole. The first recess is provided in the columnar portion. The first limiting portion and the second limiting portion are both connected to and protrude from the outer side wall of the columnar portion. The first limiting portion and the second limiting portion are respectively provided on the outer and inner sides of the cover along the first direction and are used to clamp a portion of the cover.

20. The battery cell of claim 19, wherein, The columnar portion, the first limiting portion, and the second limiting portion are an integral structure.

21. The battery cell of claim 19 or 20, wherein, The battery cell further includes a first insulating member and a second insulating member, at least a portion of the first insulating member being disposed between the first limiting portion and the cover, and at least a portion of the second insulating member being disposed between the second limiting portion and the cover. The first insulating member and the second insulating member are used to insulate and isolate the terminal body from the cover.

22. The battery cell of claim 21, wherein, The first insulating member and the second insulating member are integrally formed into a structure; or, The first insulating member and the second insulating member are provided separately and abut against each other.

23. The battery cell of any one of claims 21-22, wherein, One of the first insulating member and the second insulating member is used to seal the electrode lead-out hole.

24. The battery cell of any one of claims 19-23, wherein, The outer periphery of the first limiting part is provided with a plurality of protruding structures, which are spaced apart along the circumferential direction of the columnar part.

25. The battery cell of claim 24, wherein, The first limiting part is a flange structure formed by folding outward from the end of the terminal body away from the electrode assembly.

26. The battery cell of any one of claims 19-25, wherein, The second limiting portion is a limiting structure formed by pressing the end of the terminal body facing the electrode assembly to extend the end of the terminal body facing the electrode assembly outward.

27. The battery cell of any one of claims 9-26, wherein, The terminal body has a second outer surface and a second inner surface disposed opposite to each other along the first direction, and the first recess extends from the second outer surface to the first outer surface of the connection portion along the direction facing the electrode assembly.

28. The battery cell of claim 27, wherein, The electrode terminal also includes a sealing plate, which is connected to the terminal body and closes the opening of the first recess.

29. The battery cell of claim 28, wherein, The first recess has a stepped surface on its sidewall, at least a portion of the sealing plate is accommodated in the first recess, and the stepped surface is used to support the sealing plate.

30. The battery cell of claim 28 or 29, wherein, A gap is provided between the sealing plate and the connecting part, and the gap is used to avoid the second welding part.

31. The battery cell according to any one of claims 27-30, wherein, The connecting portion is located at one end of the terminal body facing the electrode assembly, and the first inner surface of the connecting portion is flush with the second inner surface.

32. The battery cell according to any one of claims 27-30, wherein, The terminal body further includes a second recess, which is recessed from the second inner surface in a direction away from the electrode assembly to the first inner surface of the connection portion.

33. The battery cell of claim 32, wherein, The current collector includes a terminal connection portion and an electrode connection portion surrounding the outside of the terminal connection portion. The terminal connection portion protrudes relative to the electrode connection portion and extends into the second recess, such that the top of the terminal connection portion abuts against the first inner surface of the connection portion.

34. The battery cell of claim 33, wherein, The current collector has a fourth recess at a position corresponding to the terminal connection portion, and the fourth recess is recessed relative to the surface of the electrode connection portion facing the first electrode.

35. The battery cell of any one of claims 9-26, wherein, The terminal body has a second outer surface and a second inner surface disposed opposite to each other along the first direction, and the first recess extends from the second inner surface into the first inner surface of the connection portion in a direction away from the electrode assembly.

36. The battery cell of claim 35, wherein, The current collector includes a terminal connection portion and an electrode connection portion surrounding the outside of the terminal connection portion. The terminal connection portion protrudes relative to the electrode connection portion and extends into the first recess, such that the top of the terminal connection portion abuts against the first inner surface of the connection portion.

37. The battery cell of any one of claims 9-33, wherein, The terminal body has a second outer surface and a second inner surface disposed opposite to each other along the first direction, and the first recess is recessed from the second outer surface to the first outer surface of the connection portion along the direction facing the electrode assembly; The electrode terminal also includes a sealing plate, which is connected to the terminal body and closes the opening of the first recess. The sealing plate is used to weld to the battery's busbar component and form a third welded part.

38. The battery cell of claim 37, wherein, At least a portion of the sealing plate protrudes from the second outer surface of the terminal body.

39. The battery cell of claim 37 or 38, wherein, At least a portion of the sealing plate is accommodated in the first recess, and a stepped surface for supporting the sealing plate is provided on the side wall of the first recess. The sealing plate is welded to the sidewall of the first recess to form a fourth welded portion, which is used to seal the opening of the first recess.

40. The battery cell of claim 39, wherein, The third welded part is entirely located within the area enclosed by the fourth welded part.

41. The battery cell of claim 39 or 40, wherein, In the direction away from the connection portion, the fourth weld portion does not extend beyond the upper surface of the sealing plate.

42. The battery cell of any one of claims 1-41, wherein, The electrode assembly further includes a second electrode tab, which is disposed around the central axis of the electrode assembly; The first electrode tab and the second electrode tab are respectively disposed at both ends of the electrode assembly along the first direction; The cylindrical body is used to connect the second electrode tab and the cover body so that the second electrode tab and the cover body are electrically connected.

43. The battery cell of claim 42, wherein, The second electrode tab is the negative electrode tab, and the base material of the shell is steel.

44. The battery cell of any one of claims 1-43, wherein, The first tab is wound around the central axis of the electrode assembly to form multiple tab layers; The first annular portion includes at least two rings of the tab layers.

45. The battery cell of claim 44, wherein, The total number of turns of the electrode layer of the first electrode is N1; The first annular portion is welded to the current collecting member to form a first welded portion, and the total number of turns of the tab layer connected to the first welded portion is N2; N1 and N2 satisfy: 0.3≤N2 / N1≤0.

7.

46. The battery cell of any one of claims 1-45, wherein, The electrode assembly includes a negative electrode sheet, and the negative electrode active material of the negative electrode sheet includes silicon.

47. The battery cell of any one of claims 1-46, wherein, The shell is cylindrical.

48. A battery comprising a plurality of battery cells according to any one of claims 1-47 and a busbar, the busbar being used to electrically connect at least two of the battery cells.

49. An electrical device comprising a battery according to claim 48, the battery being used to provide electrical energy.

50. A method for manufacturing a single battery cell, comprising: A housing and a terminal body are provided. The housing includes a cylindrical body and a cover connected to the cylindrical body. The cover and the cylindrical body are integrally formed. The cylindrical body has an opening at one end away from the cover. The cover is provided with an electrode lead-out hole. The terminal body is installed in the electrode lead-out hole. An electrode assembly is provided, the electrode assembly including a first electrode tab disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; Provide a current collection component and connect the current collection component to the first annular portion; The electrode assembly and the current collector are installed into the housing, and the current collector and the terminal body are connected so that the first tab and the terminal body are electrically connected. Provide a cover plate and attach the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along a first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction, and at least a portion of the current collecting member is located between the cover and the first annular portion.

51. The manufacturing method according to claim 50, wherein, The terminal body is provided with a first recess, and a connecting portion is formed at the bottom of the first recess; The step of installing the electrode assembly and the current collector into the housing, and connecting the current collector and the terminal body includes: The electrode assembly and the current collector are installed into the housing, and the current collector is pressed against the connection portion. External welding equipment is applied to the surface of the connection part away from the current collector to weld the connection part and the current collector.

52. The manufacturing method according to claim 51, wherein, The terminal body has a second outer surface and a second inner surface disposed opposite to each other along the first direction, and the first recess is recessed from the second outer surface to the first outer surface of the connection portion along the direction facing the electrode assembly; The manufacturing method further includes: providing a sealing plate, placing at least a portion of the sealing plate into the first recess and welding the sealing plate and the sidewall of the first recess to close the opening of the first recess.

53. A system for manufacturing a single battery cell, comprising: A first providing device is used to provide a housing and a terminal body. The housing includes a cylindrical body and a cover connected to the cylindrical body. The cover and the cylindrical body are integrally formed. The cylindrical body has an opening at one end away from the cover. The cover is provided with an electrode lead-out hole. The terminal body is installed in the electrode lead-out hole. A second providing device is used to provide an electrode assembly, the electrode assembly including a first tab, the first tab being disposed around the central axis of the electrode assembly, the first tab including a first annular portion; A third providing device is used to provide a current collecting component and connect the current collecting component to the first annular portion; An assembly device for installing the electrode assembly and the current collector into the housing, and connecting the current collector and the terminal body so that the first tab and the terminal body are electrically connected; A fourth providing device is used to provide a cover plate and connect the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along a first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction, and at least a portion of the current collecting member is located between the cover and the first annular portion.

54. A method for manufacturing a single battery cell, comprising: A current collector and a terminal body are provided, and the current collector and the terminal body are connected. An electrode assembly is provided, the electrode assembly including a first electrode tab disposed around the central axis of the electrode assembly, the first electrode tab including a first annular portion; The current collector is connected to the first annular portion so that the first electrode tab and the terminal body are electrically connected; A housing is provided, the housing including a cylindrical body and a cover connected to the cylindrical body, the cover and the cylindrical body being integrally formed, the cylindrical body having an opening at one end opposite to the cover, and the cover being provided with an electrode lead-out hole; The electrode assembly and the current collector are installed into the housing, and the terminal body is installed into the electrode lead-out hole; Provide a cover plate and attach the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along a first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction, and at least a portion of the current collecting member is located between the cover and the first annular portion.

55. The manufacturing method of claim 54, wherein, The steps of installing the electrode assembly and the current collector into the housing and installing the terminal body into the electrode lead-out hole include: The electrode assembly and the current collector are installed into the housing, and the end of the terminal body facing away from the electrode assembly extends out of the cover through the electrode lead-out hole; A flange structure is formed by folding the end of the terminal body away from the electrode assembly outward to fix the terminal body to the cover.

56. The manufacturing method of claim 54, wherein, The steps of installing the electrode assembly and the current collector into the housing and installing the terminal body into the electrode lead-out hole include: The electrode assembly and the current collector are installed into the housing, and the end of the terminal body facing away from the electrode assembly extends out of the cover through the electrode lead-out hole; The end of the terminal body facing away from the electrode assembly is squeezed to extend the end outward to form a limiting structure for fixing the terminal body to the cover.

57. A system for manufacturing a single battery cell, comprising: A first providing device is used to provide a current collector and a terminal body, and to connect the current collector and the terminal body; A second providing device is used to provide an electrode assembly, the electrode assembly including a first tab, the first tab being disposed around the central axis of the electrode assembly, the first tab including a first annular portion; A first assembly device is used to connect the current collector to the first annular portion so that the first electrode tab and the terminal body are electrically connected. A third providing device is used to provide a housing, the housing including a cylindrical body and a cover connected to the cylindrical body, the cover and the cylindrical body being integrally formed, the cylindrical body having an opening at one end away from the cover, and the cover having an electrode lead-out hole; The second assembly device is used to install the electrode assembly and the current collector into the housing, and to install the terminal body into the electrode lead-out hole; A fourth providing device is used to provide a cover plate and connect the cover plate to the cylinder to close the opening of the cylinder; The cylindrical body is arranged around the outer periphery of the electrode assembly, the central axis extends along a first direction and passes through the electrode lead-out hole, the first annular portion is arranged opposite to the cover, and the projection of the first annular portion in the first direction does not overlap with the projection of the electrode lead-out hole in the first direction, and at least a portion of the current collecting member is located between the cover and the first annular portion.

Images