CN219937323U

CN219937323U - Battery monomer, battery and power consumption device

Info

Publication number: CN219937323U
Application number: CN202320594570.2U
Authority: CN
Inventors: 林蹬华; 陈龙; 陈新祥; 黄守君; 郑于炼; 王鹏; 金海族
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-03-23
Filing date: 2023-03-23
Publication date: 2023-10-31
Anticipated expiration: 2033-03-23

Abstract

The application discloses a battery monomer, a battery and an electric device, wherein the battery monomer comprises an electrode assembly, a shell and an electrode terminal, the electrode assembly is at least partially accommodated in the shell, the electrode terminal is electrically connected with the electrode assembly, and the electrode terminal is arranged on the wall part of the shell; the electrode terminal comprises a first metal layer body and a second metal layer body which are made of different materials, the first metal layer body is positioned on one side of the second metal layer body facing the electrode assembly along the thickness direction of the wall part, the first metal layer body is connected with the second metal layer body to form a connecting interface, and at least part of the connecting interface is a curved surface. According to the battery monomer provided by the embodiment of the application, at least part of the connecting interface between the first metal layer body and the second metal layer body which are made of different materials is set to be the curved surface, so that the connecting strength between the first metal layer body and the second metal layer body is effectively improved, the risk of fracture of an electrode terminal is reduced, and the performance of the battery monomer is improved.

Description

Battery monomer, battery and power consumption device

Technical Field

The application relates to the technical field of batteries, in particular to a battery monomer, a battery and an electric device.

Background

At present, in order to ensure the connection strength between the electrode terminal and other components of the battery cell, the electrode terminal is usually made of different metal materials in a composite mode, but due to the fact that the connection strength between the two metal materials is poor, two parts of the electrode terminal, which are different in material, are prone to fracture, and the performance of the battery cell is not improved.

Disclosure of Invention

One of the purposes of the embodiments of the present utility model is: a battery cell, a battery and an electric device are provided, and the technical problem that electrode terminals made of different metal materials in a composite mode are easy to break is solved.

In order to solve the technical problems, the technical scheme adopted by the embodiment of the utility model is as follows:

in a first aspect, there is provided a battery cell including an electrode assembly at least partially received in a case, and an electrode terminal electrically connected to the electrode assembly, the electrode terminal being provided on a wall portion of the case; the electrode terminal comprises a first metal layer body and a second metal layer body which are made of different materials, the first metal layer body is positioned on one side of the second metal layer body facing the electrode assembly along the thickness direction of the wall part, the first metal layer body is connected with the second metal layer body to form a connecting interface, and at least part of the connecting interface is a curved surface.

The battery monomer provided by the embodiment of the application has the beneficial effects that: according to the battery monomer provided by the embodiment of the application, at least part of the connecting interface between the first metal layer body and the second metal layer body which are made of different materials is set to be the curved surface, so that the connecting area between the first metal layer body and the second metal layer body is effectively increased, the connecting strength between the first metal layer body and the second metal layer body is effectively improved, the risk of fracture of an electrode terminal is reduced, and the performance of the battery monomer is improved.

In some embodiments of the present application, the electrode terminal has a first central axis parallel to the thickness direction, and the connection interface includes a first connection surface and a second connection surface located at an outer periphery of the first connection surface, the first central axis passing through the first connection surface, the first connection surface being a curved surface.

By adopting the technical scheme, the middle part of the connecting interface is a curved surface, so that the sufficient connecting area is ensured between the middle part of the first metal layer body and the middle part of the second metal layer body, the connecting strength between the first metal layer body and the second metal layer body is effectively improved, and the risk of fracture of the electrode terminal is reduced.

In some embodiments of the application, the first connection surface has a second central axis parallel to the thickness direction, the second central axis coinciding with the first central axis.

Through adopting above-mentioned technical scheme for the connection between first metal layer body and the second metal layer body is in the ascending atress of circumference of electrode terminal more even, but the connecting area between the middle part of further increasing first metal layer body and the middle part of second metal layer body simultaneously, thereby further improved the joint strength between first metal layer body and the second metal layer body, further reduced the risk that electrode terminal appears the fracture condition.

In some embodiments of the present application, the first metal layer is a copper layer, the second metal layer is an aluminum layer, and the first connection surface is concavely disposed in a direction approaching the electrode assembly with respect to the second connection surface in a thickness direction.

By adopting the technical scheme, the material amount of the first metal layer body is effectively reduced, so that the manufacturing cost of the electrode terminal is effectively reduced.

In some embodiments of the present application, the battery cell further includes an adapter for connecting the electrode assembly and the first metal layer body to electrically connect the electrode assembly and the electrode terminal; the first metal layer body comprises a first connecting part for connecting the adapter, and at least one part of the first connecting part is arranged opposite to the first connecting surface.

Through adopting above-mentioned technical scheme for at least a portion of first connecting portion and the relative setting of first junction surface, because first junction surface is the curved surface, the area is great, and junction between first metal layer body and the second metal layer body is great with the joint strength of the corresponding part of first junction surface, can effectively overcome the tractive force that the adaptor acted on first metal layer body, thereby has further reduced the risk that electrode terminal appears the fracture condition.

In some embodiments of the present application, the first connection portion is welded to the adapter and forms a first weld.

By adopting the technical scheme, the electrode terminal is convenient to be connected with the adapter.

In some embodiments of the application, the first weld does not extend beyond the first connection face in a direction in which the electrode assembly points toward the electrode terminal.

By adopting the technical scheme, the connection interface can be prevented from being damaged, so that the connection strength between the first metal layer body and the second metal layer body is ensured, and the risk of fracture of the electrode terminal is further reduced.

In some embodiments of the present application, in the thickness direction, the thickness of the portion of the first connection portion at the first solder is H1, and the thickness of the portion of the first solder located at the first connection portion is H2, 0.6.ltoreq.h2/h1.ltoreq.0.9.

Through adopting above-mentioned technical scheme, both can guarantee the joint strength between first connecting portion and the adaptor, also can reduce first connecting portion and be welded the risk that leads to the connection interface to receive the destruction, effectively guarantee the joint strength between first metal layer body and the second metal layer body to the risk of electrode terminal appearance fracture condition has further been reduced.

In some embodiments of the present application, a positioning structure is disposed between the first metal layer and the adaptor, and the first solder is disposed on an outer periphery of the positioning structure.

Through adopting above-mentioned technical scheme, effectively inject the relative position of adaptor and electrode terminal to improve the condition that appears mutual displacement in the connection in-process of adaptor and electrode terminal, effectively guarantee the connection effect between adaptor and the electrode terminal, can improve simultaneously that first welding seal and location structure produce the condition of interference, effectively improved the coverage area of first welding seal, thereby effectively improved the joint strength between electrode terminal and the adaptor.

In some embodiments of the application, the positioning structure comprises mating protrusions and recesses, one of the first metal layer and the adapter being provided with protrusions and the other being provided with recesses.

By adopting the technical scheme, the relative positions of the adapter and the electrode terminal are conveniently limited.

In some embodiments of the application, the first metal layer is provided with a protrusion, and the adapter is provided with a recess, which is a through hole penetrating the adapter.

In some embodiments of the application, the adapter is provided with a groove, the recess penetrates through the bottom of the groove, and the first welding mark is arranged at the bottom of the groove and is spaced from the recess.

Through adopting above-mentioned technical scheme, be convenient for realize restricting the relative position of adaptor and electrode terminal, can improve simultaneously that first welding seal and location structure produce the condition of interference, effectively improved the coverage area of first welding seal to effectively improved the joint strength between electrode terminal and the adaptor.

In some embodiments of the present application, the adapter is provided with a groove, the recess penetrates the bottom of the groove, and the protrusion penetrates the recess and is fixedly connected to a side of the bottom of the groove facing the electrode assembly.

Through adopting above-mentioned technical scheme, be convenient for realize restricting the relative position of adapter and electrode terminal, effectively improve simultaneously the joint strength between electrode terminal and the adapter.

In some embodiments of the application, the second metal layer body includes a second connection portion for connecting the external bus member, at least a portion of the second connection portion being disposed opposite the first connection face.

Through adopting above-mentioned technical scheme for at least a portion of second connecting portion and the relative setting of first junction surface, because first junction surface is the curved surface, the area is great, and junction between first metal layer body and the second metal layer body is great with the joint strength of the corresponding part of first junction surface, can effectively overcome the tractive force that outside collector acted on the second metal layer body, thereby has further reduced the risk that electrode terminal appears the fracture condition.

In some embodiments of the application, the second connection portion is welded to the external bus bar and forms a second weld.

By adopting the technical scheme, the electrode terminal is convenient to be connected with an external bus piece.

In some embodiments of the application, the second solder marks do not protrude beyond the first connection surface in a direction in which the electrode terminals are directed toward the electrode assembly.

In some embodiments of the present application, a thickness of a portion of the second connection portion at the second solder mark is H3, and a thickness of a portion of the second solder mark at the second connection portion is H4, 0.6.ltoreq.H2 3.ltoreq.0.9 in a thickness direction.

Through adopting above-mentioned technical scheme, both can guarantee the joint strength between second connecting portion and the outside piece that converges, also can reduce the second connecting portion and be welded the risk that leads to the connection interface to receive the destruction, effectively guarantee the joint strength between first metal layer body and the second metal layer body to the risk of electrode terminal appearance fracture condition has further been reduced.

In some embodiments of the application, the second connection surface is a curved surface.

By adopting the technical scheme, the area of the connecting interface can be further increased, so that the connecting strength between the first metal layer body and the second metal layer body is further improved, and the risk of fracture of the electrode terminal is further reduced.

In some embodiments of the application, the electrode terminal has a first central axis parallel to the thickness direction, the connection interface has a second central axis parallel to the thickness direction, and the second central axis coincides with the first central axis; the projection of the connection interface along the thickness direction has a first length in a first direction, the projection of the electrode terminal along the thickness direction has a second length in the first direction, the first length is equal to the second length, and the first direction passes through a first central axis of the electrode terminal and is perpendicular to the thickness direction.

In some embodiments of the present application, the projection of the outer peripheral edge of the connection interface in the thickness direction coincides with the projection of the outer peripheral edge of the electrode terminal in the thickness direction.

By adopting the technical scheme, the area of the connecting interface can be increased to the greatest extent, so that the connecting strength between the first metal layer body and the second metal layer body is further improved, and the risk of fracture of the electrode terminal is further reduced.

In some embodiments of the application, the projection of the wall portion in the thickness direction is rectangular, and the first direction is the length direction or the width direction of the wall portion; alternatively, the projection of the wall portion in the thickness direction is annular, and the first direction is a radial direction of the wall portion.

By adopting the technical scheme, the first direction can be set according to the specific shape of the wall part.

In some embodiments of the application, the point of the connecting interface closest to the electrode assembly is less than or equal to 6mm from the first central axis.

By adopting the technical scheme, the part with larger area of the connecting interface is as close to the first central axis of the electrode terminal as possible, so that the connecting force of the part, near the first central axis of the electrode terminal, of the connection between the first metal layer body and the second metal layer body is increased, the connecting strength between the first metal layer body and the second metal layer body is further improved, and the risk of fracture of the electrode terminal is further reduced.

In some embodiments of the application, the connection interface is located closest to the point of the electrode assembly on the first central axis.

By adopting the technical scheme, the part with larger area of the connecting interface concentrates on the first central axis of the electrode terminal, so that the connecting force of the part, connected between the first metal layer body and the second metal layer body, on the first central axis of the electrode terminal is increased, the connecting strength between the first metal layer body and the second metal layer body is further improved, and the risk of fracture condition of the electrode terminal is further reduced.

In some embodiments of the present application, the distance H5 between the point where the connection interface is farthest from the electrode assembly and the point where the connection interface is closest to the electrode assembly is 1 mm.ltoreq.H5.ltoreq.10mm in the thickness direction.

Through adopting above-mentioned technical scheme, through adopting above-mentioned technical scheme for the height of connection interface in the thickness direction of wall is unlikely to too little, effectively guarantees the area of connection interface, thereby guarantees the joint strength between first metal layer body and the second metal layer body, has reduced the risk that the fracture condition appears in electrode terminal, also makes the height of connection interface in the thickness direction of wall unlikely to too big simultaneously, thereby guarantees that first metal layer body and second metal layer body have sufficient thickness, reduces the risk that first metal layer body runs through the second metal layer body or second metal layer body runs through first metal layer body, is favorable to improving the performance of battery monomer.

In some embodiments of the present application, the battery cell further includes an insulating member and a fixing member, the wall portion is provided with an electrode lead-out hole, the fixing member is connected to the wall portion and is disposed around the electrode lead-out hole, at least a portion of the electrode terminal is accommodated in an accommodating space defined by the fixing member, the insulating member is disposed between the fixing member and the electrode terminal, and the fixing member abuts against the electrode terminal through the insulating member so that the electrode terminal is fixed to the wall portion.

Through adopting above-mentioned technical scheme, the insulating part can be with mounting and electrode terminal insulation separation, reduces the risk that short circuit appears between mounting and the electrode terminal, is favorable to promoting the free performance of battery.

In some embodiments of the application, the battery cell further comprises a seal at least partially between the wall portion and the electrode terminal.

By adopting the technical scheme, the risk that electrolyte in the shell leaks from between the electrode terminal and the wall part is reduced, and the performance of the battery cell is improved.

In some embodiments of the application, the casing includes a housing and an end cap, one end of the housing has an opening, the end cap covers the opening, the housing includes a side wall and a bottom wall, the side wall is arranged on the outer side of the electrode assembly in a surrounding manner, the bottom wall is arranged opposite to the opening, and the wall part is the end cap or the bottom wall or the side wall.

By adopting the technical scheme, the electrode terminal can be arranged on the end cover or the bottom wall or the side wall.

In a second aspect, an embodiment of the present application further provides a battery, including the battery cell of any one of the above embodiments.

The battery provided by the embodiment of the application has the beneficial effects that: the battery provided by the embodiment of the application adopts the battery monomer of any one embodiment, so that the performance of the battery is effectively improved.

In a third aspect, an embodiment of the present application further provides an electrical apparatus, including the above battery.

The power utilization device provided by the embodiment of the application has the beneficial effects that: the power utilization device provided by the embodiment of the application effectively improves the performance of the power utilization device due to the adoption of the battery of any one embodiment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or exemplary technical descriptions will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.

Fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application;

fig. 2 is an exploded view of a battery according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

FIG. 4 is an exploded view of the battery cell shown in FIG. 3;

fig. 5 is a schematic front view of the electrode terminal in the battery cell shown in fig. 4;

fig. 6 is a schematic cross-sectional view of the electrode terminal shown in fig. 5 along the line A-A;

fig. 7 is a schematic view illustrating a connection structure between the battery cell and the external bus bar shown in fig. 3;

FIG. 8 is a schematic cross-sectional view of the structure of FIG. 7 taken along line B-B;

FIG. 9 is an enlarged schematic view of the first structure of FIG. 8 at C;

FIG. 10 is an enlarged schematic diagram of the second structure at C in FIG. 8;

FIG. 11 is an enlarged schematic diagram III of the structure of FIG. 8 at C;

Fig. 12 is a schematic view of a projection structure of an electrode terminal and a connection interface thereof along a thickness direction of a wall portion according to an embodiment of the present application.

Reference numerals illustrate:

1000. a vehicle;

100. a battery;

10. a case; 11. a first portion; 12. a second portion; 13. an accommodation space;

20. a battery cell; 21. a housing; 211. a housing; 212. an end cap; 2121. electrode lead-out holes; 22. an electrode terminal; 221. a first metal layer; 2211. a first connection portion; 2212. a convex portion; 22121. a fourth connecting portion; 222. a second metal layer; 2221. a second connecting portion; 223. a connection interface; 2231. a first connection surface; 2232. a second connection surface; 224. a first central axis; 225. a first solder printing; 226. a second solder printing; 23. an electrode assembly; 231. a tab; 24. an adapter; 241. a concave portion; 242. a groove; 25. an insulating member; 26. a fixing member; 261. a pressing portion; 262. a third connecting portion; 27. a seal; 28. an insulating separator; 29. a pressure release mechanism;

30. an external bus member;

200. a controller;

300. a motor.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. are based on the orientation or positional relationship shown in the drawings, are for convenience of description only, and are not intended to indicate or imply that the apparatus or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the application, and the specific meaning of the terms described above will be understood by those of ordinary skill in the art as appropriate. The terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "a plurality of" is two or more, unless specifically defined otherwise.

In the embodiments of the present application, the same reference numerals denote the same components, and detailed descriptions of the same components are omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width, etc. dimensions of the various components in the embodiments of the application shown in the drawings are merely illustrative and should not be construed as limiting the application in any way.

The battery cell, as a minimum unit constituting the battery, generally includes a case, an electrode assembly, and electrode terminals. The electrode assembly is disposed within the case, and the electrode terminals are disposed on a wall portion of the case. One part of the electrode terminal extends into the internal environment of the battery cell and is connected with the electrode assembly through the adapter, and the other part of the electrode terminal is exposed out of the external environment of the battery cell and is connected with the bus bar so as to input or output electric energy of the battery cell. However, in actual use, the electrode terminals are easily broken, thereby affecting the performance of the battery cell.

One of the reasons why the electrode terminal is easily broken is that: the metal material used for the bus member is different from the metal material used for the adapter, for example, the metal material used for the bus member is aluminum, the metal material used for the adapter is copper, and the connection strength between the different metal materials is poor. In the electrode terminal, the connection interface between the two parts with different materials is usually a plane, so that the area of the connection interface is smaller, resulting in poor connection strength of the two parts with different materials of the electrode terminal.

In order to reduce the risk of fracture of the electrode terminal, the embodiment of the application provides the electrode terminal, wherein at least part of a connecting interface between a first metal layer body and a second metal layer body which are made of different materials is arranged to be a curved surface, so that the connecting area between the first metal layer body and the second metal layer body is effectively increased, the connecting strength between the first metal layer body and the second metal layer body is effectively improved, and the risk of fracture of the electrode terminal is reduced.

The battery cell, the battery and the power utilization device using the battery as the power supply disclosed by the embodiment of the application can be, but are not limited to, vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like. Spacecraft include airplanes, rockets, space planes, spacecraft, and the like. The electric toy includes fixed or mobile electric toys such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy, and the like. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others.

For convenience of description, the following embodiments will take an electric device according to an embodiment of the present application as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to an embodiment of the application. The vehicle 1000 may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. The battery 100 is provided in the interior of the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may be used as an operating power source of the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.

In some embodiments of the application, battery 100 may not only serve as an operating power source for vehicle 1000, but may also serve as a driving power source for vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to an embodiment of the application. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide the accommodating space 13 for the battery cell 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, the first portion 11 and the second portion 12 being overlapped with each other, the first portion 11 and the second portion 12 together defining an accommodating space 13 for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one end opened, the first portion 11 may be a plate-shaped structure, and the first portion 11 is covered on the opening side of the second portion 12, so that the first portion 11 and the second portion 12 together define the accommodating space 13; the first portion 11 and the second portion 12 may be hollow structures with one side open, and the open side of the first portion 11 is disposed on the open side of the second portion 12. Of course, the case 10 formed by the first portion 11 and the second portion 12 may be of various shapes, such as a cylinder, a rectangular parallelepiped, or the like.

In some embodiments, the tank 10 may be part of the chassis structure of the vehicle 1000. For example, a portion of the tank 10 may become at least a portion of the floor of the vehicle 1000, or a portion of the tank 10 may become at least a portion of the cross and side members of the vehicle 1000.

In the battery 100, the plurality of battery cells 20 may be connected in series, parallel or a series-parallel connection, wherein the series-parallel connection refers to that the plurality of battery cells 20 are connected in series or parallel. The plurality of battery cells 20 can be directly connected in series, in parallel or in series-parallel, and then the whole body formed by the plurality of battery cells 20 is accommodated in the box 10. Of course, the battery 100 may also be a battery module formed by connecting a plurality of battery cells 20 in series or parallel or series-parallel connection, and then connecting a plurality of battery modules in series or parallel or series-parallel connection to form a whole and be accommodated in the case 10. The battery 100 may also include other functional components, for example, the battery 100 may also include a buss bar for making electrical connection between the plurality of battery cells 20.

Each of the battery cells 20 may be a secondary battery or a primary battery, where the secondary battery refers to a battery cell that can activate an active material by charging after the battery cell discharges and continue to use, and the primary battery refers to a battery cell that cannot activate an active material by charging after the battery cell is depleted of electric energy; the battery cell 20 may be, but not limited to, a lithium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, or the like. The battery cell 20 may be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or other shaped battery cell, and the prismatic battery cell includes a square case battery cell, a blade battery cell, a polygonal prismatic battery cell, such as a hexagonal battery cell, etc., and the present application is not particularly limited.

Of course, in some embodiments, the battery 100 may not include the case 10, but a plurality of battery cells 20 may be electrically connected and integrated by a necessary fixing structure to be assembled into the power consumption device.

Referring to fig. 3 and fig. 4 together, fig. 3 is a schematic structural diagram of a battery cell 20 according to an embodiment of the application, and fig. 4 is an exploded schematic diagram of the battery cell 20 shown in the drawings. The battery cell 20 refers to the smallest unit constituting the battery 100. The battery cell 20 includes a case 21, an electrode assembly 23, an electrode terminal 22, and other functional components.

The case 21 includes a case 211 and an end cap 212, the case 211 being a member for providing an internal environment of the battery cell 20, wherein the internal environment may be used to accommodate the electrode assembly 23, the electrolyte, and other functional components. The case 211 may be a separate member, and an opening may be provided in the case 211, and the end cap 212 may be provided to the opening to form an internal environment of the battery cell 20 in which the electrode assembly 23, the electrolyte, and the like are accommodated. Specifically, the housing 211 and the end cap 212 may form a common connection surface before other components are put into the housing, and when the interior of the housing 211 needs to be sealed, the end cap 212 is covered on the opening of the housing 211. Alternatively, the housing 211 may be of various shapes and various sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the case 211 may be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 211 may be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and is not particularly limited herein.

The end cap 212 refers to a member that is provided at the opening of the case 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 212 may be adapted to the shape of the housing 211 to fit the housing 211. In some embodiments, the end cap 212 may be made of a material having a certain hardness and strength, so that the end cap 212 is not easy to deform when being impacted by extrusion, so that the battery cell 20 can have a higher structural strength, and the safety performance can be improved. Of course, the material of the end cap 212 is not limited to this embodiment, and the end cap 212 may be made of copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, a pressure relief mechanism 29 may also be provided on the end cap 212 for relieving the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. In some embodiments, an insulating spacer 28 may also be provided at the end cap 212, the insulating spacer 28 may be used to isolate electrical connection components within the housing 211 from the end cap 212 to reduce the risk of shorting. Alternatively, the insulating spacer 28 may be made of, but not limited to, plastic, rubber, etc.

The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. The battery cell 20 may include one or more electrode assemblies 23. The electrode assembly 23 is mainly made of a positive electrode sheet, a negative electrode sheet, and a separator using a winding process or a lamination process.

In some embodiments, the electrode assembly 23 is a coiled structure. The positive plate and the negative plate are wound into a winding structure.

In some embodiments, electrode assembly 23 is a lamination stack.

As an example, a plurality of positive electrode sheets and negative electrode sheets may be provided, respectively, and a plurality of positive electrode sheets and a plurality of negative electrode sheets may be alternately stacked.

As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheets are folded to form a plurality of folded sections arranged in a stacked manner, with one positive electrode sheet sandwiched between adjacent folded sections.

As an example, the positive and negative electrode sheets are each folded to form a plurality of folded sections in a stacked arrangement.

As an example, the separator may be provided in plurality, respectively between any adjacent positive electrode sheet or negative electrode sheet.

As an example, the separator may be continuously provided, being disposed between any adjacent positive or negative electrode sheets by folding or winding.

During charge and discharge of the battery cell 20, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive and negative electrode tabs. The separator is arranged between the positive plate and the negative plate, can play a role in preventing the positive plate and the negative plate from being short-circuited, and can enable active ions to pass through.

The positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

As an example, the positive electrode current collector has two surfaces opposing in its own thickness direction, and the positive electrode active material is provided on either or both of the two surfaces opposing the positive electrode current collector.

As an example, the positive electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, titanium, or the like can be used. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material may be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of the lithium-containing phosphate may include, but are not limited to, at least one of lithium iron phosphate (e.g., liFePO4 (which may also be abbreviated as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., liMnPO 4), a composite of lithium manganese phosphate and carbon, lithium manganese phosphate, and a composite of lithium manganese phosphate and carbon. Examples of the lithium transition metal oxide may include, but are not limited to, at least one of lithium cobalt oxide (e.g., liCoO 2), lithium nickel oxide (e.g., liNiO 2), lithium manganese oxide (e.g., liMnO2, liMn2O 4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide (e.g., liNi1/3Co1/3Mn1/3O2 (may also be abbreviated as NCM 333), lini0.5co0.2mn0.3o2 (may also be abbreviated as NCM 523), lini0.5co0.25mn0.25o2 (may also be abbreviated as NCM 211), lini0.6co0.2mn0.2o2 (may also be abbreviated as NCM 622), lini0.8co0.1mn0.1o2 (may also be abbreviated as NCM 811), lithium nickel cobalt aluminum oxide (e.g., lini0.85co0.15 al0.05o2), and modified compounds thereof.

In some embodiments, the positive electrode may be a metal foam. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, foam carbon or the like. When the metal foam is used as the positive electrode, the surface of the metal foam may not be provided with the positive electrode active material, but may be provided with the positive electrode active material. As an example, a lithium source material, which is lithium metal and/or a lithium-rich material, potassium metal or sodium metal, may also be filled and/or deposited within the foam metal.

The negative electrode sheet may include a negative electrode current collector.

As an example, the negative electrode current collector may employ a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, titanium, or the like can be used. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, foam carbon or the like. The composite current collector may include a polymeric material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

As an example, the anode current collector has two surfaces opposing in its own thickness direction, and the anode active material is provided on either or both of the two surfaces opposing the anode current collector.

As an example, a negative active material known in the art for the battery cell 20 may be used. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like. The silicon-based material may be at least one selected from elemental silicon, silicon oxygen compounds, silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material may be at least one selected from elemental tin, tin oxide, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery anode active material may be used. These negative electrode active materials may be used alone or in combination of two or more.

In some embodiments, the material of the positive electrode current collector may be aluminum and the material of the negative electrode current collector may be copper.

In some embodiments, the separator is a separator film. The type of the separator is not particularly limited, and any known porous separator having good chemical stability and mechanical stability can be used.

As an example, the main material of the separator may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of the respective layers may be the same or different, and are not particularly limited. The separator may be a single member located between the positive electrode sheet and the negative electrode sheet, or may be attached to the surface of the positive electrode sheet and the surface of the negative electrode sheet.

In some embodiments, the separator is a solid state electrolyte. The solid electrolyte is arranged between the positive plate and the negative plate and plays roles in transmitting ions and isolating the positive plate and the negative plate.

In some embodiments, the battery cell 20 further includes an electrolyte that serves to conduct ions between the positive and negative electrode sheets. The application is not particularly limited in the kind of electrolyte, and may be selected according to the need. The electrolyte may be liquid, gel or solid.

Wherein the liquid electrolyte comprises an electrolyte salt and a solvent.

In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, and lithium tetrafluorooxalato phosphate.

In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1, 4-butyrolactone, sulfolane, dimethyl sulfone, methyl sulfone, and diethyl sulfone. The solvent may also be selected from ether solvents. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1, 3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

The gel electrolyte comprises a skeleton network taking a polymer as an electrolyte and is matched with ionic liquid-lithium salt.

Wherein the solid electrolyte comprises a polymer solid electrolyte, an inorganic solid electrolyte and a composite solid electrolyte.

As examples, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single ion polymer, polyion liquid-lithium salt, cellulose, or the like.

As an example, the inorganic solid electrolyte may be one or more of an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), a sulfide solid electrolyte (crystalline lithium super ion conductor (lithium germanium phosphorus sulfide, silver sulfur germanium mine), amorphous sulfide), and a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

In some embodiments, the electrode assembly 23 may have a cylindrical shape, a flat shape, a polygonal column shape, or the like.

In some embodiments, the electrode assembly 23 is provided with tabs 231, and the tabs 231 may direct current from the electrode assembly 23. Tab 231 includes a positive tab and a negative tab.

The electrode terminals 22 are members electrically connected to the electrode assembly 23 for outputting electric power of the battery cells 20 or inputting electric power to the battery cells 20. The electrode terminal 22 may be disposed on the end cap 212, a portion of the electrode terminal 22 extends into the internal environment of the battery cell 20 and is directly or indirectly connected to the tab 231 of the electrode assembly 23, and another portion of the electrode terminal 22 is exposed to the external environment of the battery cell 20 and is connected to a bus bar, a sampling device, etc. Alternatively, the electrode terminal 22 may have a cylindrical structure, such as a cylindrical structure, a prismatic structure, or the like, the electrode terminal 22 may have a plate-like structure, such as a circular plate, a square plate, or the like, and the electrode terminal 22 may have other irregular three-dimensional structures, which are not particularly limited herein. The electrode terminal 22 may be made of one metal material or a plurality of metal materials, and the metal materials may be, but are not limited to, copper, aluminum, nickel, zinc, iron, etc., and are not particularly limited thereto.

In order to explain the technical scheme provided by the application, the following is a detailed description with reference to the specific drawings and embodiments.

In a first aspect, referring to fig. 3 to 6 together, an embodiment of the present application provides a battery cell 20, where the battery cell 20 includes an electrode assembly 23, a housing 21 and an electrode terminal 22, the electrode assembly 23 is at least partially contained in the housing 21, the electrode terminal 22 is electrically connected to the electrode assembly 23, and the electrode terminal 22 is disposed on a wall portion of the housing 21; the electrode terminal 22 includes a first metal layer 221 and a second metal layer 222 made of different materials, the first metal layer 221 is located on a side of the second metal layer 222 facing the electrode assembly 23 along a thickness direction of the wall, the first metal layer 221 and the second metal layer 222 are connected to form a connection interface 223, and at least a portion of the connection interface 223 is a curved surface.

The wall of the housing 21 may be any wall of the housing 211, for example, a side wall of the housing 211, a bottom wall of the housing 211, or the like, or may be a cover plate of the end cap 212, which is not particularly limited herein.

The material of the first metal layer 221 is different from the material of the second metal layer 222, the material of the first metal layer 221 is mainly determined according to the material of the component connected to the first metal layer 221, and the material of the second metal layer 222 is mainly determined according to the material of the component connected to the second metal layer 222, for example, the material of the component connected to the first metal layer 221 is copper, the material of the component connected to the second metal layer 222 is aluminum, and the material of the second metal layer 222 is aluminum; for example, the material of the component connected to the first metal layer 221 is copper, the material of the component connected to the second metal layer 222 is nickel, and the material of the second metal layer 222 is nickel. The first metal layer 221 and the second metal layer 222 are distributed in a thickness direction (X direction shown in fig. 6) of the wall portion of the case 21, specifically, the first metal layer 221 is located at a side of the second metal layer 222 facing the electrode assembly 23, at least a portion of the first metal layer 221 is located in the internal environment of the battery cell 20, and at least a portion of the second metal layer 222 is exposed to the external environment of the battery cell 20, so that the first metal layer 221 and the second metal layer 222 are connected with corresponding parts, for example, the first metal layer 221 is connected with the electrode assembly 23, and the second metal layer 222 is connected with the bus bar.

The connection interface 223 is an interface formed by a portion of the first metal layer 221 contacting the second metal layer 222. The connection interface 223 is at least partially curved, in other words, the connection interface 223 may be entirely curved, the connection interface 223 may be formed by both curved and flat surfaces, for example, a middle portion of the connection interface 223 is curved, an outer peripheral portion of the connection interface 223 is flat, and the connection interface 223 may be formed by both curved and inclined surfaces, for example, a middle portion of the connection interface 223 is curved, and an outer peripheral portion of the connection interface 223 is inclined. Alternatively, the curved surface may be a regular curved surface, such as a spherical surface, a parabolic surface, or the like, and the curved surface may also be an irregular curved surface, which is not particularly limited herein.

In some embodiments, the first metal layer 221 is integrally stamped with the second metal layer 222. Specifically, in order to enable at least part of the connection interface 223 to form a curved surface during the punching, the first metal layer 221 may be punched to form an uneven surface such as a stepped surface, an arc surface, or the like, in the thickness direction, and the second metal layer 222 may be punched to form a flat surface, or the second metal layer 222 may be punched to form an uneven surface such as a stepped surface, an arc surface, or the like, in the thickness direction, and the first metal layer 221 may be punched to form a flat surface, or the first metal layer 221 may be punched to form an uneven surface such as a stepped surface, an arc surface, or the like, in the thickness direction, and the second metal layer 222 may be punched to form an uneven surface such as a stepped surface, an arc surface, or the like, in the thickness direction, in the surface, or the second metal layer 222 may be punched to face away from the first metal layer 221. In this way, any of the plurality of portions of the first metal layer 221 or any of the plurality of portions of the second metal layer 222 are displaced by different magnitudes in the pressing direction, so that at least part of the connection interface 223 between the first metal layer 221 and the second metal layer 222 forms a curved surface.

In other embodiments, the first metal layer 221 may be first processed to form a first surface structure and the second metal layer 222 may be processed to form a second surface structure, at least a portion of the first surface structure and at least a portion of the second surface structure are curved surfaces, the first surface structure and the second surface structure may be concave-convex matched, and the first surface structure and the second surface structure are bonded to form the connecting interface 223, so that the first metal layer 221 and the second metal layer 222 are connected together. Alternatively, the connection between the first and second face structures may be, but is not limited to, friction welding, adhesive bonding, etc., and is not specifically limited herein.

According to the electrode terminal 22 provided by the embodiment of the application, at least part of the connecting interface 223 between the first metal layer 221 and the second metal layer 222 made of different materials is provided with the curved surface, so that the connecting area between the first metal layer 221 and the second metal layer 222 is effectively increased, the connecting strength between the first metal layer 221 and the second metal layer 222 is effectively improved, the risk of fracture of the electrode terminal 22 is reduced, and the performance of the battery cell 20 is improved.

In some embodiments of the present application, referring to fig. 6, the electrode terminal 22 has a first central axis 224 parallel to a thickness direction of the wall portion, the connection interface 223 includes a first connection surface 2231 and a second connection surface 2232 located at an outer periphery of the first connection surface 2231, the first central axis 224 passes through the first connection surface 2231, and the first connection surface 2231 is curved.

The electrode terminal 22 may have a rotationally symmetrical structure, for example, the electrode terminal 22 may have a cylindrical structure, or the electrode terminal 22 may have a non-rotationally symmetrical structure, for example, the electrode terminal 22 may have a square column structure, a prismatic structure, or the like, and is not particularly limited herein.

The first connection surface 2231 is a middle portion of the connection interface 223, the second connection surface 2232 is an outer peripheral portion of the connection interface 223, the second connection surface 2232 may have a ring structure, and the second connection surface 2232 is annularly disposed on the first connection surface 2231. The annular structure may be various, for example, a projection of the first connection surface 2231 in the thickness direction of the wall portion is circular, then a projection of the second connection surface 2232 in the thickness direction of the wall portion is circular, and for example, a projection of the first connection surface 2231 in the thickness direction of the wall portion is square, then a projection of the second connection surface 2232 in the thickness direction of the wall portion is square.

The first connection surface 2231 is a middle portion of the connection interface 223, the second connection surface 2232 is an outer peripheral portion of the connection interface 223, and based on the positions of the first connection surface 2231 and the second connection surface 2232 relative to the first central axis 224, the first connection surface 2231 is a middle portion of the connection interface 223, which indicates that the first connection surface 2231 is closer to the first central axis 224 than the second connection surface 2232, and the center of the first connection surface 2231 is not limited to be located on the first central axis 224, and a certain distance may exist between the first connection surface and the second connection surface.

In some embodiments, the first connection surface 2231 is curved and the second connection surface 2232 is planar.

In other embodiments, the first connecting surface 2231 is curved and the second connecting surface 2232 is sloped.

In still other embodiments, both the first and second attachment surfaces 2231, 2232 are curved.

Alternatively, the curved surface may be a regular curved surface, such as a spherical surface, a parabolic surface, or the like, and the curved surface may also be an irregular curved surface, which is not particularly limited herein.

By adopting the above technical scheme, the middle part of the connecting interface 223 is a curved surface, so that a sufficient connecting area is ensured between the middle part of the first metal layer 221 and the middle part of the second metal layer 222, thereby effectively improving the connecting strength between the first metal layer 221 and the second metal layer 222 and reducing the risk of fracture of the electrode terminal 22.

In some embodiments of the application, the first connection surface 2231 has a second central axis parallel to the thickness direction that coincides with the first central axis 224.

The first connection surface 2231 may have a rotationally symmetrical structure, for example, a projection of the first connection surface 2231 in the thickness direction of the wall portion may have a circular structure, or the first connection surface 2231 may have a non-rotationally symmetrical structure, for example, a projection of the first connection surface 2231 in the thickness direction of the wall portion may have an elliptical structure, a square structure, or the like, which is not particularly limited herein.

By adopting the above technical scheme, the stress of the connection part between the first metal layer 221 and the second metal layer 222 in the circumferential direction of the electrode terminal 22 is more uniform, and meanwhile, the connection area between the middle part of the first metal layer 221 and the middle part of the second metal layer 222 can be further increased, so that the connection strength between the first metal layer 221 and the second metal layer 222 is further improved, and the risk of fracture of the electrode terminal 22 is further reduced.

In some embodiments of the present application, referring to fig. 6, the first metal layer 221 is a copper layer, the second metal layer 222 is an aluminum layer, and the first connection surface 2231 is concavely disposed toward the electrode assembly 23 relative to the second connection surface 2232 in the thickness direction of the wall portion.

In practical use, the material of the negative electrode tab of the electrode assembly 23 is usually copper, and correspondingly, the material of the tab 231 of the negative electrode tab is also copper, and the material of the bus bar is usually aluminum, and the first metal layer 221 of the electrode terminal 22 is a copper layer and the second metal layer 222 is an aluminum layer, in other words, the material of the first metal layer 221 is copper, the material of the second metal layer 222 is aluminum, so that the first metal layer 221 can be connected with the tab 231 of the negative electrode tab of the electrode assembly 23, and the second metal layer 222 can be connected with the bus bar.

The concave arrangement of the first connection surface 2231 with respect to the second connection surface 2232 toward the electrode assembly 23 means that the first connection surface 2231 generally protrudes toward the electrode assembly 23, and the first connection surface 2231 may have a rounded concave surface or a concave surface with a relief structure.

By adopting the above technical scheme, the amount of material used for the first metal layer 221 is effectively reduced, thereby effectively reducing the manufacturing cost of the electrode terminal 22.

In some embodiments of the present application, referring to fig. 7 to 9 together, the battery cell 20 further includes an adapter 24, wherein the adapter 24 is used for connecting the electrode assembly 23 and the first metal layer 221 so as to electrically connect the electrode assembly 23 and the electrode terminal 22; the first metal layer 221 includes a first connection portion 2211 for connecting the adaptor 24, and at least a portion of the first connection portion 2211 is disposed opposite to the first connection surface 2231.

The adaptor 24 is used to connect the electrode assembly 23 and the first metal layer 221 to electrically connect the electrode assembly 23 and the electrode terminal 22, in other words, the adaptor 24 is an electrically conductive connection medium between the electrode assembly 23 and the electrode terminal 22, and the adaptor 24 functions to draw current of the electrode assembly 23 to the electrode terminal 22 to achieve electrical connection between the electrode assembly 23 and the electrode terminal 22. Alternatively, the material of the adaptor 24 may be, but is not limited to, copper, iron, aluminum, steel, aluminum alloy, etc.

The first connection portion 2211 is a portion of the first metal layer 221 for connection with the adapter 24. The arrangement of at least a portion of the first connection portion 2211 opposite to the first connection surface 2231 means that at least a portion of the first connection portion 2211 and the first connection surface 2231 are sequentially arranged in the thickness direction of the wall portion.

In actual use, when the first connection portion 2211 is connected to the adapter 24, the adapter 24 may generate a tensile force acting on the first metal layer 221 and directed to the electrode assembly 23, and the portion of the connection interface 223 opposite to the first connection portion 2211 may be more likely to break due to the tensile force than other portions of the connection interface 223. By arranging at least a portion of the first connection portion 2211 opposite to the first connection surface 2231, since the first connection surface 2231 is a curved surface, the area is larger, and the connection strength of the connection portion between the first metal layer 221 and the second metal layer 222 corresponding to the first connection surface 2231 is larger, the pulling force of the adaptor 24 acting on the first metal layer 221 can be effectively overcome, and thus the risk of occurrence of fracture of the electrode terminal 22 is further reduced.

In some embodiments of the present application, referring to fig. 9, the first connection portion 2211 is welded to the adapter 24 and forms a first solder 225.

The first solder 225 is formed by soldering the first connection portion 2211 and the adapter 24. At least a portion of the first solder 225 is embedded in the first connection portion 2211, at least a portion of the first solder 225 is embedded in the adapter 24, and at least a portion of the first solder 225 is located between the first connection portion 2211 and the adapter 24 to connect the first connection portion 2211 and the adapter 24.

By adopting the above technical scheme, the electrode terminal 22 is conveniently connected with the adapter 24.

In some embodiments of the present application, referring to fig. 9, the first solder 225 does not protrude beyond the first connection surface 2231 in a direction in which the electrode assembly 23 is directed toward the electrode terminal 22 (see X direction shown in fig. 9).

In other words, the thickness of the portion of the first solder 225 embedded in the first connection portion 2211 is smaller than the thickness of the first connection portion 2211 in the direction in which the electrode assembly 23 points to the electrode terminal 22, so that the first solder 225 does not extend to the first connection face 2231 through the first connection portion 2211.

By adopting the above technical scheme, the connection interface 223 can be prevented from being damaged, so that the connection strength between the first metal layer 221 and the second metal layer 222 is ensured, and the risk of fracture of the electrode terminal 22 is further reduced.

In some embodiments of the present application, referring to fig. 9, in the thickness direction of the wall portion, the thickness of the portion of the first connection portion 2211 at the first solder mark 225 is H1, and the thickness of the portion of the first solder mark 225 located at the first connection portion 2211 is H2, 0.6+.h2/h1+.0.9.

The value of H2/H1 may be specifically 0.6, 0.7, 0.8, 0.9, etc., and is not specifically limited herein. If the value of H2/H1 is too small, the depth of the first solder 225 embedded into the first connection portion 2211 is small, resulting in insufficient connection strength between the first connection portion 2211 and the adapter 24, and if the value of H2/H1 is too large, the depth of the first solder 225 embedded into the first connection portion 2211 is large, which easily results in the first solder 225 extending to the first connection surface 2231 through the first connection portion 2211, thereby resulting in insufficient connection strength between the first metal layer 221 and the second metal layer 222.

By adopting the above technical scheme, the risk that the first connection portion 2211 is welded through to cause the connection interface 223 to be damaged can be reduced, and the connection strength between the first metal layer 221 and the second metal layer 222 is effectively ensured, so that the risk that the electrode terminal 22 is broken is further reduced, and meanwhile, the first connection portion 2211 is welded through to cause the connection relationship between the second metal layer 222 and the adapter 24 can be prevented, so that the connection strength between the first connection portion 2211 and the adapter 24 can be ensured.

In some embodiments of the present application, referring to fig. 9 to 11, a positioning structure is disposed between the first metal layer 221 and the adaptor 24, and the first solder 225 is disposed on an outer periphery of the positioning structure.

The positioning structure is used for limiting the relative position between the first metal layer 221 and the adaptor 24. Alternatively, the positioning structure may be a concave-convex mating structure, a clamping positioning structure, a buckling positioning structure, or the like, which is not particularly limited herein.

In some embodiments, the first solder 225 may be disposed at any location on the outer periphery of the positioning structure, for example, the first solder 225 is a solder joint disposed on the outer periphery of the positioning structure.

In other embodiments, the first solder marks 225 may be disposed around the positioning structure, for example, the first solder marks 225 are a plurality of solder spots, and the plurality of solder spots are sequentially distributed along the peripheral direction of the positioning structure; as another example, the first solder 225 is in a ring-like configuration, and the first solder 225 surrounds the positioning structure.

Through adopting above-mentioned technical scheme, effectively inject the relative position of adaptor 24 and electrode terminal 22 to improve the condition that appears mutual displacement in the connection process of adaptor 24 and electrode terminal 22, effectively guarantee the connection effect between adaptor 24 and the electrode terminal 22, can improve simultaneously that first welding seal 225 produces the condition of interference with location structure, effectively improved the coverage area of first welding seal 225, thereby effectively improved the joint strength between electrode terminal 22 and the adaptor 24.

In some embodiments of the present application, referring to fig. 9 to 11, the positioning structure includes a protrusion 2212 and a recess 241, where one of the first metal layer 221 and the adaptor 24 is provided with the protrusion 2212, and the other is provided with the recess 241.

In some embodiments, the first metal layer 221 is provided with a protrusion 2212, where the protrusion 2212 may be disposed on the first connection portion 2211, or may be disposed at other portions of the first metal layer 221, where the protrusion 2212 protrudes along the direction of the electrode terminal 22 toward the electrode assembly 23. The adapter 24 is provided with a recess 241, and the recess 241 is concavely provided in a direction in which the electrode terminal 22 points toward the electrode assembly 23 or penetrates the adapter 24.

In other embodiments, the first metal layer 221 is provided with a concave portion 241, the concave portion 241 may be provided on the first connection portion 2211, or may be provided at other portions of the first metal layer 221, the concave portion 241 is concavely provided along the direction of the electrode assembly 23 toward the electrode terminal 22 but does not penetrate through the first metal layer 221, the adapter 24 is provided with a convex portion 2212, and the convex portion 2212 is convexly provided along the direction of the electrode assembly 23 toward the electrode terminal 22.

It is understood that the number of the protruding portions 2212 and the number of the concave portions 241 may be plural, and the plural protruding portions 2212 are arranged in one-to-one correspondence with the plural concave portions 241.

At the time of assembly, the protruding portion 2212 is inserted into the concave portion 241 to restrict the relative movement of the electrode terminal 22 and the adapter 24 in the circumferential direction of the electrode terminal 22, and then the first connection portion 2211 is welded to the adapter 24, i.e., the connection operation of the electrode terminal 22 and the adapter 24 is completed.

By adopting the above technical scheme, the restriction of the relative positions of the adapter 24 and the electrode terminal 22 is facilitated.

In some embodiments of the present application, referring to fig. 9 to 11, the first metal layer 221 is provided with a protrusion 2212, the adaptor 24 is provided with a recess 241, and the recess 241 is a through hole penetrating through the adaptor 24.

As can be appreciated, the recess 241 is a through hole provided through the adapter 24 in the thickness direction of the wall portion.

In some embodiments of the present application, referring to fig. 10, the adaptor 24 is provided with a groove 242, the recess 241 penetrates through the bottom of the groove 242, and the first solder 225 is disposed at the bottom of the groove 242 and spaced apart from the recess 241.

The grooves 242 are recessed in a direction in which the electrode terminals 22 are directed toward the electrode assembly 23. The recess 241 is disposed at the bottom of the groove 242 and penetrates the bottom of the groove 242, the first solder 225 is disposed at the bottom of the groove 242, in other words, the protrusion 2212 is inserted into the recess 241 through the groove 242, at least part of the first connection portion 2211 is disposed in the groove 242 and soldered with the bottom of the groove 242 to form the first solder 225, and at the same time, the first solder 225 is disposed at intervals from the recess 241 along the circumferential direction of the positioning structure.

By adopting the technical scheme, the relative positions of the adapter 24 and the electrode terminal 22 are conveniently limited, the interference between the first welding mark 225 and the positioning structure can be improved, the coverage area of the first welding mark 225 is effectively increased, and the connection strength between the electrode terminal 22 and the adapter 24 is effectively improved.

In some embodiments of the present application, referring to fig. 11, the adapter 24 is provided with a groove 242, a recess 241 penetrates through the bottom of the groove 242, and a protrusion 2212 penetrates through the recess 241 and is fixedly connected to a side of the bottom of the groove 242 facing the electrode assembly 23.

It is understood that after the protrusion 2212 passes through the recess 241, at least part of the protrusion 2212 protrudes out of the recess 241 along the direction of the electrode terminal 22 toward the electrode assembly 23, the portion of the protrusion 2212 protruding out of the recess 241 is connected to the side of the bottom of the groove 242 facing the electrode assembly 23, specifically, the side of the protrusion 2212 facing away from the second metal layer 222 is provided with a fourth connection portion 22121, the side of the fourth connection portion 22121 facing the electrode assembly 23 is connected to the bottom of the groove 242, and the connection manner between the fourth connection portion 22121 and the bottom of the groove 242 may be, but is not limited to, riveting, welding, and the like, which is not limited thereto.

By adopting the above technical scheme, the relative position of the adapter 24 and the electrode terminal 22 is conveniently limited, and meanwhile, under the dual effects that the first connecting part 2211 is connected with the adapter 24 and the convex part 2212 is connected with the bottom of the groove 242, the connection strength between the electrode terminal 22 and the adapter 24 is effectively improved.

In some embodiments of the present application, referring to fig. 9, the second metal layer 222 includes a second connection portion 2221 for connecting the external bus bar 30, at least a portion of the second connection portion 2221 being disposed opposite to the first connection surface 2231.

The second connection portion 2221 is a portion of the first metal layer 221 for connection with the external bus bar 30. The arrangement of at least a portion of the second connection portion 2221 opposite to the first connection surface 2231 means that at least a portion of the second connection portion 2221 and the first connection surface 2231 are sequentially arranged in the thickness direction of the wall portion.

In actual use, when the second connection portion 2221 is connected to the external bus bar 30, the external bus bar 30 may generate a tensile force acting on the second metal layer 222 and pointing away from the electrode assembly 23, and the portion of the connection interface 223 opposite to the second connection portion 2221 may be more likely to break due to the tensile force than other portions of the connection interface 223. By arranging at least a portion of the second connection portion 2221 opposite to the first connection surface 2231, since the first connection surface 2231 is a curved surface, the area is larger, and the connection strength of the connection portion between the first metal layer 221 and the second metal layer 222 at the portion corresponding to the first connection surface 2231 is larger, the pulling force of the external bus bar 30 acting on the second metal layer 222 can be effectively overcome, thereby further reducing the risk of occurrence of fracture conditions of the electrode terminal 22.

In some embodiments of the present application, referring to fig. 9, the second connection portion 2221 is welded to the external bus bar 30 and forms a second weld 226.

The second solder mark 226 is formed by soldering the second connection portion 2221 and the external bus member 30. At least a portion of the second welding mark 226 is embedded in the second connection portion 2221, at least a portion of the second welding mark 226 is embedded in the external bus member 30, and at least a portion of the second welding mark 226 is located between the second connection portion 2221 and the external bus member 30 to connect the second connection portion 2221 and the external bus member 30.

By adopting the above-described technical scheme, it is convenient to achieve connection of the electrode terminal 22 with the external bus bar 30.

In some embodiments of the present application, referring to fig. 9, the second solder 226 does not protrude beyond the first connection surface 2231 in a direction in which the electrode terminal 22 is directed toward the electrode assembly 23 (in a direction opposite to the X direction shown in fig. 9).

In other words, the thickness of the portion of the second solder 226 embedded in the second connection portion 2221 is smaller than the thickness of the second connection portion 2221 in the direction in which the electrode assembly 23 points to the electrode terminal 22, so that the second solder 226 does not extend to the first connection face 2231 through the second connection portion 2221.

In some embodiments of the present application, referring to fig. 9, in the thickness direction, the thickness of the portion of the second connection portion 2221 at the second solder mark 226 is H3, and the thickness of the portion of the second solder mark 226 at the second connection portion 2221 is H4, 0.6+.h4/h3+.0.9.

The value of H4/H3 may be specifically 0.6, 0.7, 0.8, 0.9, etc., and is not specifically limited herein. If the value of H4/H3 is too small, the depth of the second solder 226 embedded into the second connection portion 2221 is small, resulting in insufficient connection strength between the second connection portion 2221 and the external bus bar 30, and if the value of H4/H3 is too large, the depth of the second solder 226 embedded into the second connection portion 2221 is large, which easily results in the second solder 226 extending to the first connection surface 2231 through the second connection portion 2221, thereby resulting in insufficient connection strength between the first metal layer 221 and the second metal layer 222.

By adopting the above technical scheme, the risk that the second connection portion 2221 is welded through to cause the connection interface 223 to be damaged can be reduced, and the connection strength between the first metal layer 221 and the second metal layer 222 is effectively ensured, so that the risk that the electrode terminal 22 is broken is further reduced, and meanwhile, the second connection portion 2221 is welded through to cause the connection relationship between the part of the first metal layer 221 and the external bus member 30 can be prevented, so that the connection strength between the second connection portion 2221 and the external bus member 30 can be ensured.

In some embodiments of the present application, referring to fig. 6, the second connecting surface 2232 is curved.

By adopting the above technical scheme, the area of the connection interface 223 can be further increased, so that the connection strength between the first metal layer 221 and the second metal layer 222 is further improved, and the risk of fracture of the electrode terminal 22 is further reduced.

In some embodiments of the present application, referring to fig. 12, the electrode terminal 22 has a first central axis 224 parallel to the thickness direction, and the connection interface 223 has a second central axis parallel to the thickness direction of the wall portion, the second central axis coinciding with the first central axis 224; the projection K of the connection interface 223 in the thickness direction of the wall portion has a first length L1 in the first direction, the projection J of the electrode terminal 22 in the thickness direction of the wall portion has a second length L2 in the first direction, the first length L1 is equal to the second length L2, and the first direction passes through the first central axis 224 of the electrode terminal 22 and is perpendicular to the thickness direction of the wall portion.

One plane defined perpendicular to the thickness direction of the wall portion is a projection plane, and two points of the projected outer peripheral edge of the connection interface 223 on the projection plane in the first direction coincide with the projected outer peripheral edge of the electrode terminal 22 on the projection plane, that is, opposite sides of the connection interface 223 in the first direction extend onto the outer peripheral edge of the electrode terminal 22.

The first direction may be any direction passing through the first central axis 224 of the electrode terminal 22 and perpendicular to the thickness direction of the wall portion, for example, the Y direction shown in fig. 6.

In some embodiments of the present application, the projection of the outer peripheral edge of the connection interface 223 in the thickness direction of the wall portion coincides with the projection of the outer peripheral edge of the electrode terminal 22 in the thickness direction of the wall portion.

In other words, the projection of the connection interface 223 on the projection surface and the projection of the electrode terminal 22 on the projection surface are completely overlapped, that is, the outer peripheral edge of the connection interface 223 is overlapped with the outer peripheral edge of the electrode terminal 22.

By adopting the technical scheme, the area of the connecting interface 223 can be increased to the greatest extent, so that the connecting strength between the first metal layer 221 and the second metal layer 222 is further improved, and the risk of fracture of the electrode terminal 22 is further reduced.

The first direction may be set according to the specific shape of the wall portion.

In some embodiments of the application, the wall portion is rectangular in projection in the thickness direction, the first direction being the length direction or the width direction of the wall portion.

In other embodiments of the application, the projection of the wall portion in the thickness direction is annular, the first direction being radial of the wall portion.

In some embodiments of the present application, referring to fig. 6, the point I of the connection interface 223 closest to the electrode assembly 23 is less than or equal to 6mm from the first central axis 224 of the electrode terminal 22.

The point of the connection interface 223 closest to the electrode assembly 23 refers to the point of the connection interface 223 having the smallest distance from the electrode assembly 23, and the distance from the first central axis 224 of the electrode terminal 22 refers to the linear distance between the point and the first central axis 224 of the electrode terminal 22, and the linear distance may be specifically 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, etc., and may be specifically determined according to practical needs.

By adopting the above technical solution, the larger area of the connecting interface 223 is as close to the first central axis 224 of the electrode terminal 22 as possible, so as to increase the connecting force of the portion, near the first central axis 224 of the electrode terminal 22, of the connection between the first metal layer 221 and the second metal layer 222, thereby further improving the connecting strength between the first metal layer 221 and the second metal layer 222 and further reducing the risk of fracture of the electrode terminal 22.

In addition, in the case where the first metal layer 221 is a copper layer and the second metal layer 222 is an aluminum layer, the above-described technical scheme can further reduce the amount of the first metal layer 221, thereby further reducing the manufacturing cost of the electrode terminal 22.

In some embodiments of the application, the point I of the connection interface 223 closest to the electrode assembly 23 is located on the first central axis 224.

By adopting the technical scheme, the area of the connecting interface 223, which is close to the first central axis 224 of the electrode terminal 22, is larger, so that the connecting force of the part, which is connected with the first metal layer 221 and the second metal layer 222 and is positioned on the first central axis 224 of the electrode terminal 22, is increased, the connecting strength between the first metal layer 221 and the second metal layer 222 is further improved, and the risk of fracture of the electrode terminal 22 is further reduced.

In addition, in the case where the first metal layer 221 is a copper layer and the second metal layer 222 is an aluminum layer, the above-mentioned technical scheme can further reduce the amount of the first metal layer 221, thereby further reducing the manufacturing cost of the electrode terminal 22.

In some embodiments of the present application, referring to FIG. 6, in the thickness direction of the wall portion, the distance H5 between the point where the connection interface 223 is farthest from the electrode assembly 23 and the point where the connection interface 223 is closest to the electrode assembly 23 is 1 mm.ltoreq.H5.ltoreq.10mm.

It is understood that the distance H5 between the point of the connection interface 223 farthest from the electrode assembly 23 and the point of the connection interface 223 closest to the electrode assembly 23 is the height of the connection interface 223 in the thickness direction of the wall portion, and the distance H5 may be specifically 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, and may be specifically determined according to practical needs.

By adopting the above technical scheme, the height of the connection interface 223 in the thickness direction of the wall body is not too small, the area of the connection interface 223 is effectively ensured, the connection strength between the first metal layer 221 and the second metal layer 222 is ensured, the risk of fracture of the electrode terminal 22 is reduced, meanwhile, the height of the connection interface 223 in the thickness direction of the wall body is not too large, the first metal layer 221 and the second metal layer 222 are ensured to have enough thickness, the risk that the first metal layer 221 penetrates through the second metal layer 222 or the second metal layer 222 penetrates through the first metal layer 221 is reduced, and the performance of the battery cell 20 is improved.

In some embodiments of the present application, referring to fig. 9 to 11 together, the battery cell 20 further includes an insulating member 25 and a fixing member 26, the wall portion is provided with an electrode lead-out hole 2121, the fixing member 26 is connected to the wall portion and is disposed around the electrode lead-out hole 2121, at least a portion of the electrode terminal 22 is accommodated in the accommodating space 13 defined by the fixing member 26, the insulating member 25 is disposed between the fixing member 26 and the electrode terminal 22, and the fixing member 26 abuts against the electrode terminal 22 through the insulating member 25, so that the electrode terminal 22 is fixed on the wall portion.

The fixing member 26 is a member protruding from the surface of the wall portion of the case 21 and surrounding the electrode lead-out hole 2121, and the electrode terminal 22 is at least partially located in the space surrounded by the fixing member 26, and it is understood that the electrode terminal 22 may be partially or entirely located in the space surrounded by the fixing member 26; the electrode terminal 22 is electrically connected to the adaptor 24 through the electrode lead-out hole 2121, and further electrically connected to the electrode assembly 23, so as to output and input electrical energy from the battery cell 20. For example, the first connection portion 2211 of the first metal layer body 221 is connected to the electrode assembly 23 through the adapter 24 after passing through the electrode lead-out hole 2121; of course, in other implementations, at least a portion of the adapter 24 may be electrically connected to the electrode terminal 22 after passing through the electrode lead hole 2121. In some embodiments, an insulating spacer 28 is also provided between the adaptor 24 and the wall, the insulating spacer 28 insulating the adaptor 24 from the wall, reducing the risk of short circuits.

The fixing member 26 and the wall portion of the housing 21 are integrally formed, and for example, the fixing member 26 and the wall portion of the housing 21 are manufactured and molded by an integral process such as extrusion, injection molding, and die casting. The fixing member 26 may be an annular integral structure, and the fixing member 26 may also be a segmented structure that is annularly provided along the circumferential direction of the electrode terminal 22. Wherein, the fixing piece 26 and the wall part of the shell 21 are of an integrated structure, so that the assembly process can be reduced, the cost can be saved, and the structural strength is good.

The fixing member 26 includes a pressing portion 261 and a third connecting portion 262, the third connecting portion 262 being a portion of the fixing member 26 located between the pressing portion 261 and a wall portion of the housing 21, the third connecting portion 262 serving to connect the pressing portion 261 and the wall portion of the housing 21 and also serving to support the pressing portion 261. The pressing portion 261 is a portion of the fixing member 26 for applying a pressing force to the electrode terminal 22, and the electrode terminal 22 is fixed to the wall portion of the case 21 by the pressing action of the pressing portion 261. The pressing portion 261 may be an annular integral structure that is annularly provided outside the electrode terminal 22, and the pressing portion 261 may also be a segmented structure that is annularly provided along the circumferential direction of the electrode terminal 22.

The insulating member 25 is a member made of an insulating material, and the insulating member 25 is positioned between the fixing member 26 and the electrode terminal 22 to insulate the fixing member 26 from the electrode terminal 22, thereby reducing the risk of short circuit. The insulator 25 may have a ring-shaped structure, and the insulator 25 is disposed around the electrode terminal 22. It will be appreciated that the insulating member 25 is made of an insulating material, alternatively, but not limited to, polyester, epoxy, polyurethane, polybutadiene acid, silicone, polyester imide, polyimide, etc., and is not particularly limited thereto.

By adopting the above technical scheme, the insulating member 25 can insulate and separate the fixing member 26 and the electrode terminal 22, so that the risk of short circuit between the fixing member 26 and the electrode terminal 22 is reduced, and the performance of the battery cell 20 is improved.

In some embodiments of the present application, referring to fig. 9 to 11 together, the battery cell 20 further includes a sealing member 27, and the sealing member 27 is at least partially positioned between the wall portion and the electrode terminal 22.

The seal 27 is a member that can perform a sealing function, and the seal 27 is at least partially sandwiched between the electrode terminal 22 and the wall portion of the case 21, and the seal 27 can deform under the clamping force generated by the combined action of the electrode terminal 22 and the wall portion of the case 21, thereby realizing a gap seal between the electrode terminal 22 and the wall portion of the case 21. The sealing member 27 may have an annular structure, and the sealing member 27 is disposed around the electrode terminal 22. The seal 27 may be, but is not limited to, a gasket, a seal ring. The seal member 27 may be partially sandwiched between the electrode terminal 22 and the wall portion of the case 21, or the entire seal member 27 may be sandwiched between the electrode terminal 22 and the wall portion of the case 21.

By adopting the above technical scheme, the risk of leakage of electrolyte in the casing 21 from between the electrode terminal 22 and the wall portion is reduced, which is beneficial to improving the performance of the battery cell 20.

In some embodiments of the present application, referring to fig. 3 and 4 together, the housing 21 includes a housing 211 and an end cap 212, one end of the housing 211 has an opening, the end cap 212 covers the opening, the housing 211 includes a sidewall and a bottom wall, the sidewall is disposed around the outside of the electrode assembly 23, the bottom wall is disposed opposite to the opening, and the wall is the end cap 212 or the bottom wall or the sidewall.

The side wall of the housing 211 encloses the internal environment of the housing 21, and both ends of the side wall are provided with openings, the bottom wall of the housing 211 is covered on one opening of the side wall, and the end cover 212 is covered on the other opening of the side wall. The electrode terminal 22 may be disposed on the end cap 212, on the side wall of the case 211, or on the bottom wall of the case 211, as may be required.

In a second aspect, an embodiment of the present application further provides a battery 100, referring to fig. 2, where the battery 100 includes the battery cell 20 according to any one of the above embodiments.

The battery 100 according to the embodiment of the present application adopts the battery cell 20 according to any one of the embodiments, so that the performance of the battery 100 is effectively improved.

In a third aspect, an embodiment of the present application further provides an electrical device, referring to fig. 1, where the electrical device includes the battery 100.

The power utilization device provided by the embodiment of the application effectively improves the performance of the power utilization device due to the adoption of the battery 100 of any one of the embodiments.

The foregoing is merely an alternative embodiment of the present application and is not intended to limit the present application. Various modifications and variations of the present application will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A battery cell, the battery cell comprising:

an electrode assembly;

a housing within which the electrode assembly is at least partially housed;

an electrode terminal electrically connected to the electrode assembly, the electrode terminal being provided on a wall portion of the case;

the electrode terminal comprises a first metal layer body and a second metal layer body which are made of different materials, the first metal layer body is located on one side, facing the electrode assembly, of the second metal layer body along the thickness direction of the wall portion, the first metal layer body and the second metal layer body are connected to form a connecting interface, and at least part of the connecting interface is a curved surface.

2. The battery cell according to claim 1, wherein the electrode terminal has a first central axis parallel to the thickness direction, the connection interface includes a first connection surface through which the first central axis passes, and a second connection surface located at an outer periphery of the first connection surface, the first connection surface being a curved surface.

3. The battery cell of claim 2, wherein the first connection surface has a second central axis parallel to the thickness direction, the second central axis coinciding with the first central axis.

4. The battery cell according to claim 2, wherein the first metal layer is a copper layer, the second metal layer is an aluminum layer, and the first connection surface is concavely disposed in a direction approaching the electrode assembly with respect to the second connection surface in the thickness direction.

5. The battery cell of claim 2, further comprising an adapter for connecting the electrode assembly and the first metal layer to electrically connect the electrode assembly and the electrode terminal;

The first metal layer body comprises a first connecting part used for connecting the adapter, and at least one part of the first connecting part is arranged opposite to the first connecting surface.

6. The battery cell of claim 5, wherein the first connection portion is welded to the adapter and forms a first weld.

7. The battery cell of claim 6, wherein the first weld does not extend beyond the first connection face in a direction in which the electrode assembly points toward the electrode terminal.

8. The battery cell according to claim 7, wherein in the thickness direction, a thickness of a portion of the first connection portion at the first solder is H1, and a thickness of a portion of the first solder at the first connection portion is H2, 0.6.ltoreq.h2/H1.ltoreq.0.9.

9. The battery cell of claim 6, wherein a positioning structure is disposed between the first metal layer and the adapter, and the first solder is disposed on an outer periphery of the positioning structure.

10. The battery cell of claim 9, wherein the locating structure comprises mating protrusions and recesses, one of the first metal layer and the adapter being provided with the protrusions and the other being provided with the recesses.

11. The battery cell of claim 10, wherein the first metal layer is provided with a protrusion and the adapter is provided with a recess, the recess being a through hole extending through the adapter.

12. The battery cell of claim 11, wherein the adapter is provided with a recess, the recess extends through a bottom of the recess, and the first solder is disposed on the bottom of the recess and is spaced apart from the recess.

13. The battery cell according to claim 11, wherein the adapter is provided with a groove, the recess penetrates a bottom of the groove, and the protrusion penetrates the recess and is fixedly connected to a side of the bottom of the groove facing the electrode assembly.

14. The battery cell of claim 2, wherein the second metal layer body includes a second connection portion for connecting an external bus member, at least a portion of the second connection portion being disposed opposite the first connection face.

15. The battery cell of claim 14, wherein the second connection portion is welded to the external buss member and forms a second weld.

16. The battery cell of claim 15, wherein the second weld does not extend beyond the first connection face in a direction in which the electrode terminal points toward the electrode assembly.

17. The battery cell according to claim 16, wherein a thickness of a portion of the second connection portion at the second solder joint is H3, and a thickness of a portion of the second solder joint at the second connection portion is H4, 0.6.ltoreq.h4/H3.ltoreq.0.9 in the thickness direction.

18. The battery cell of claim 2, wherein the second connection surface is a curved surface.

19. The battery cell according to claim 1, wherein the electrode terminal has a first central axis parallel to the thickness direction, the connection interface has a second central axis parallel to the thickness direction, and the second central axis coincides with the first central axis;

the projection of the connecting interface along the thickness direction has a first length in a first direction, the projection of the electrode terminal along the thickness direction has a second length in the first direction, the first length is equal to the second length, and the first direction passes through a first central axis of the electrode terminal and is perpendicular to the thickness direction.

20. The battery cell according to claim 19, wherein a projection of an outer peripheral edge of the connection interface in the thickness direction coincides with a projection of an outer peripheral edge of the electrode terminal in the thickness direction.

21. The battery cell of claim 19, wherein the cell comprises a plurality of cells,

the projection of the wall part along the thickness direction is rectangular, and the first direction is the length direction or the width direction of the wall part; or,

the projection of the wall part along the thickness direction is annular, and the first direction is the radial direction of the wall part.

22. The battery cell of claim 19, wherein a point of the connection interface closest to the electrode assembly is less than or equal to 6mm from the first central axis.

23. The battery cell of claim 22, wherein a point of the connection interface closest to the electrode assembly is located on the first central axis.

24. The battery cell of claim 19, wherein in the thickness direction, a distance H5 between a point of the connection interface furthest from the electrode assembly and a point of the connection interface closest to the electrode assembly is 1mm ∈h5 ∈10mm.

25. The battery cell according to any one of claims 1 to 24, further comprising an insulating member and a fixing member, wherein the wall portion is provided with an electrode lead-out hole, the fixing member is connected to the wall portion and is disposed around the electrode lead-out hole, at least a portion of the electrode terminal is accommodated in an accommodation space defined by the fixing member, the insulating member is disposed between the fixing member and the electrode terminal, and the fixing member presses the electrode terminal through the insulating member to fix the electrode terminal to the wall portion.

26. The battery cell of claim 25, further comprising a seal at least partially between the wall portion and the electrode terminal.

27. The battery cell of any one of claims 1-24, wherein the housing comprises a shell and an end cap, wherein the shell has an opening at one end, wherein the end cap covers the opening, wherein the shell comprises a side wall and a bottom wall, wherein the side wall is disposed around the outside of the electrode assembly, wherein the bottom wall is disposed opposite to the opening, and wherein the wall is the end cap or the bottom wall or the side wall.

28. A battery comprising the battery cell of any one of claims 1-27.

29. An electrical device comprising the battery of claim 28.