Battery monomer, battery device and electric device

Abstract

The utility model belongs to the technical field of battery device pole pieces, and particularly relates to a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell and an electrode assembly, and the shell is provided with an electrode leading-out part; the electrode assembly is at least partially accommodated in the shell, the electrode assembly comprises a first pole piece, and the first pole piece comprises a conductive component, a current collector and an active material layer; the conductive member is connected with the electrode lead-out part; the current collector comprises an insulating substrate and a metal layer, and the insulating substrate, the metal layer and the active material layer are stacked in the thickness direction of the current collector; the metal layer comprises a main body part and at least one protruding part, the protruding part extends outwards from the main body part along the end part of the first direction, and each protruding part is connected with the conductive component; the protruding part comprises a first protruding sub-part connected to the main body part; in the second direction, the sum of the sizes of the first protruding sub-parts of all the protruding parts is more than 0.5 times of the size of the main body part, and the second direction is perpendicular to the first direction and the thickness direction of the current collector.

Description

Technical Field

[0001] This application belongs to the technical field of battery fast charging, and particularly relates to a battery cell, a battery device, and an electrical device. Background Art

[0002] Battery cells are widely used in electronic devices, such as mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools, etc.

[0003] A battery device includes one or more battery cells to meet different requirements for capacitance usage; however, in the technology of battery cells, how to improve the fast charging performance of battery cells is an important research direction.

[0004] The above statements are only used to provide background technical information related to this application, and do not necessarily constitute prior art. Summary of the Utility Model

[0005] The purpose of the embodiments of this application is to provide a battery cell, a battery device, and an electrical device, including but not limited to being able to improve the fast charging performance of the battery cell.

[0006] The technical solution adopted in the embodiments of this application is as follows:

[0007] In a first aspect, in some embodiments, a battery cell is provided. The battery cell includes a housing and an electrode assembly. The housing is provided with an electrode lead-out portion; at least a part of the electrode assembly is accommodated in the housing. The electrode assembly includes a first electrode tab. The first electrode tab includes a conductive member, a current collector, and an active material layer; the conductive member is connected to the electrode lead-out portion; the current collector includes an insulating substrate and a metal layer. The insulating substrate, the metal layer, and the active material layer are stacked along the thickness direction of the current collector. At least a part of the metal layer is located between the insulating substrate and the active material layer; the metal layer includes a main body portion and at least one protruding portion. The protruding portion extends outward from an end of the main body portion along a first direction. The first direction is perpendicular to the thickness direction of the current collector. Each protruding portion is connected to the conductive member; at least a part of the area of the main body portion is covered with the active material layer, and at least a part of the protruding portion is not covered with the active material layer; the protruding portion includes a first protruding sub-portion connected to the main body portion; along a second direction, the sum of the sizes of the first protruding sub-portions of all the protruding portions is more than 0.5 times the size of the main body portion, where the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0008] By adopting the technical solution of this embodiment, when the battery cell is in normal use, the electrode lead-out part is used to input or output electric energy, realizing the charging and discharging of the battery cell; and along the second direction, the sum of the sizes of the first protruding sub-parts of all the protruding parts is more than 0.5 times the size of the main body part, increasing the total current-carrying area between the protruding part and the main body part, improving the total current-carrying capacity between the protruding part and the main body part, being beneficial to improving the current-carrying capacity of the first electrode sheet, reducing the heat generation of the battery cell, being beneficial to improving the charging efficiency and discharging efficiency of the battery cell, and improving the fast charging performance of the battery cell. In addition, the current collector adopts a composite structure of an insulating matrix and a metal layer. Compared with a current collector made of pure metal, the thickness of the metal layer is small, and the burrs generated by the metal layer during the manufacturing process of the current collector are small, reducing the risk of internal short circuit of the battery cell and being beneficial to improving the use reliability of the battery cell; therefore, the battery cell of the embodiment of the present application can better balance the current-carrying capacity and use reliability.

[0009] In some embodiments, along the second direction, the sum of the sizes of the first protruding sub-parts of all the protruding parts is more than 0.6 times the size of the main body part.

[0010] By adopting the technical solution of this embodiment, the total current-carrying area between the protruding part and the main body part can be effectively increased, the total current-carrying capacity between the protruding part and the main body part can be improved, being beneficial to improving the current-carrying capacity of the first electrode sheet, reducing the heat generation of the battery cell, being beneficial to improving the charging efficiency and discharging efficiency of the battery cell, and improving the fast charging performance of the battery cell.

[0011] In some embodiments, the conductive member includes a first connection part and at least one second connection part. The first connection part and the second connection part are arranged along the first direction, the first connection part and the second connection part are connected, the second connection part is connected to the electrode lead-out part, the first connection part is welded to the surface of the metal layer facing away from the insulating matrix to form a first welding mark, and the second connection part is located on the side of the protruding part facing away from the main body part; along the first direction, the first welding mark is located on the side of the active material layer facing the protruding part.

[0012] By adopting the technical solution of this embodiment, the first connection part is welded to the metal layer, and the conductive member and the metal layer are connected by welding, which is convenient for the manufacture of the first electrode sheet; the thickness of the metal layer is small, and the surface of the metal layer facing away from the insulating matrix is large, being beneficial to increasing the welding area between the conductive member and the metal layer, increasing the current-carrying area between the conductive member and the metal layer, being beneficial to improving the current-carrying capacity of the first electrode sheet, and improving the fast charging performance of the battery cell; the second connection part protrudes outside the main body part, which is convenient for connecting the second connection part to the electrode lead-out part, and the processing and manufacturing are more convenient; at the same time, the risk of problems such as virtual soldering between the first connection part and the metal layer can also be reduced, being beneficial to improving the connection reliability between the metal layer and the conductive member, and also being beneficial to improving the current-carrying capacity of the first electrode sheet, the fast charging performance and use reliability of the battery cell.

[0013] In some embodiments, the first solder mark includes a first solder mark portion, and the first connecting portion is welded to the surface of the protruding portion facing away from the insulating substrate to form the first solder mark portion.

[0014] By adopting the technical solution of this embodiment, the first connecting portion and the protruding portion are connected by welding, and the connection method is simple, which is convenient for the production of the first pole piece; in addition, the first connecting portion and the protruding portion can directly use the first solder mark portion for current conduction, which is beneficial to improving the current conduction ability between the first connecting portion and the protruding portion.

[0015] In some embodiments, along the second direction, the first solder mark portion extends from one side edge of the protruding portion to the other side edge of the protruding portion.

[0016] By adopting the technical solution of this embodiment, the size of the first solder mark portion along the second direction is large, which is beneficial to increasing the current conduction area between the first connecting portion and the protruding portion, improving the current conduction ability between the first connecting portion and the protruding portion, reducing the heat generation of the battery cell, and improving the fast charging performance and use reliability of the battery cell.

[0017] In some embodiments, the protruding portion further includes a second protruding sub-portion, and the first protruding sub-portion is connected between the second protruding sub-portion and the main body portion; along the second direction, the size of the first protruding sub-portion is larger than that of the second protruding sub-portion; the first solder mark portion includes a first solder mark sub-portion, and the first connecting portion is welded to the first protruding sub-portion to form the first solder mark sub-portion.

[0018] By adopting the technical solution of this embodiment, the first connecting portion is welded to the first protruding sub-portion to form the first solder mark sub-portion. The size of the first protruding sub-portion along the second direction is large, which is beneficial to increasing the welding area between the protruding portion and the first connecting portion, increasing the current conduction area between the protruding portion and the first connecting portion, improving the current conduction ability, reducing the heat generation of the battery cell, and improving the fast charging performance and use reliability of the battery cell; in addition, along the second direction, the size of the second protruding sub-portion is small, which is beneficial to reducing the occupied space of the protruding portion and improving the energy density of the battery cell.

[0019] In some embodiments, along the second direction, the first solder mark sub-portion extends from one side edge of the first protruding sub-portion to the other side edge of the first protruding sub-portion.

[0020] By adopting the technical solution of this embodiment, the size of the first solder mark sub-portion along the second direction is large, which is beneficial to increasing the welding area between the protruding portion and the first connecting portion, increasing the current conduction area between the protruding portion and the main body portion, improving the current conduction ability, reducing the heat generation of the battery cell, and improving the fast charging performance and use reliability of the battery cell.

[0021] In some embodiments, the first welding mark portion further includes a second welding mark sub-portion, and the first connecting portion is welded to the surface of the second protruding sub-portion facing away from the insulating substrate to form the second welding mark sub-portion.

[0022] By adopting the technical solution of this embodiment, the second protruding sub-portion is also welded to the first connecting portion, which is beneficial to increasing the current-carrying area between the first connecting portion and the protruding portion, and is beneficial to improving the current-carrying capacity between the first connecting portion and the protruding portion.

[0023] In some embodiments, along the second direction, the second welding mark sub-portion extends from one side edge of the second protruding sub-portion to the other side edge of the second protruding sub-portion.

[0024] By adopting the technical solution of this embodiment, the size of the second welding mark sub-portion along the second direction is large, which is beneficial to increasing the welding area between the first connecting portion and the protruding portion, increasing the current-carrying area between the first connecting portion and the protruding portion, and is beneficial to improving the current-carrying capacity between the first connecting portion and the protruding portion.

[0025] In some embodiments, the number of protruding portions is multiple, the multiple protruding portions are arranged at intervals along the second direction, and each protruding portion is welded to the first connecting portion.

[0026] By adopting the technical solution of this embodiment, the multiple protruding portions are arranged at intervals along the second direction, which is beneficial to dividing the main body portion into multiple regions along the second direction, and one region can correspond to one protruding portion. The electrons in each region can be transmitted to the electrode lead-out portion through the corresponding protruding portion, so that the electrons are transmitted in sub-regions. The transmission path of the electrons in each region to the corresponding protruding portion is short, which is beneficial to reducing the transmission distance of the electrons, reducing the overall resistance of the first pole piece, and improving the fast charge performance and use reliability of the battery cell.

[0027] In some embodiments, the first connecting portion includes multiple first connecting sub-portions, the multiple first connecting sub-portions are arranged at intervals along the second direction, the number of the second connecting portions is multiple, and each first connecting sub-portion is connected to each second connecting portion in one-to-one correspondence; each first connecting sub-portion is welded to the surface of each protruding portion facing away from the insulating substrate.

[0028] By adopting the technical solution of this embodiment, the multiple first connecting sub-portions of the first connecting portion are arranged at intervals along the second direction, and there is a gap between two adjacent first connecting sub-portions, which can reduce the materials required for the first connecting portion and reduce the manufacturing cost of the battery cell.

[0029] In some embodiments, the main body portion includes a transition portion and a conductive portion, the transition portion is connected between the protruding portion and the conductive portion, the conductive portion is covered with an active material layer, and the transition portion and the protruding portion are not covered with an active material layer; the first connecting portion is connected to the surface of the transition portion facing away from the insulating substrate.

[0030] By adopting the technical solution of this embodiment, the surface of the transition part in the main body part facing away from the insulating substrate is connected to the first connection part, so that a part of the current can flow directly into or out of the first connection part through the transition part, reducing the overcurrent pressure between the protruding part and the main body part, which is beneficial to reducing the heat generation of the battery cell and improving the fast charging performance and service reliability of the battery cell.

[0031] In some embodiments, along the second direction, the size of the conductive part is L1, and the size of the transition part is L2, where 0.8 ≤ L2 / L1 ≤ 1.

[0032] By adopting the technical solution of this embodiment, along the second direction, the size of the transition part is close to that of the conductive part, and the size of the transition part is relatively large, which is beneficial to increasing the connection area between the first connection part and the transition part, improving the overcurrent capacity at the connection between the first connection part and the transition part, enhancing the overcurrent capacity of the first pole piece, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell.

[0033] In some embodiments, the first welding mark further includes a second welding mark part, and the first connection part is welded to the surface of the transition part facing away from the insulating substrate to form the second welding mark part.

[0034] By adopting the technical solution of this embodiment, the first connection part and the transition part are connected by welding, and the connection method is simple, which is beneficial to facilitating the manufacture of the first pole piece; in addition, the second welding mark part can be directly used for overcurrent between the first connection part and the transition part, which is beneficial to improving the overcurrent capacity between the first connection part and the transition part and reducing the heat generation of the battery cell.

[0035] In some embodiments, along the second direction, the size of the transition part is L2, and the size of the second welding mark part is L3, where 0.8 ≤ L3 / L2 ≤ 1.

[0036] By adopting the technical solution of this embodiment, the size of the transition part along the second direction is relatively large, which is beneficial to increasing the connection area between the first connection part and the transition part, improving the overcurrent capacity at the connection between the first connection part and the transition part, enhancing the overcurrent capacity of the first pole piece, reducing the heat generation of the battery cell, and improving the fast charging performance and service reliability of the battery cell.

[0037] In some embodiments, the number of protruding parts is multiple, and the multiple protruding parts are arranged at intervals along the second direction; the first connection part includes a second connection sub - part and multiple first connection sub - parts, the multiple first connection sub - parts are arranged at intervals along the second direction, and each first connection sub - part is welded to the surface of each protruding part facing away from the insulating substrate one by one; the number of second connection parts is multiple, along the first direction, one side of each first connection sub - part is connected to each second connection part one by one, the other side of each first connection sub - part is connected to the second connection sub - part, and the second connection sub - part is continuously arranged along the second direction; the second connection sub - part is welded to the surface of the transition part facing away from the insulating substrate.

[0038] By adopting the technical solution of this embodiment, the second connecting sub - part is continuously arranged along the second direction, and multiple first connecting sub - parts can be connected into a whole. The second connecting sub - part can play a good supporting role for the first connecting sub - part, reducing the risk of the first connecting sub - part being bent when inserted between the first pole piece and the second pole piece, reducing the short - circuit risk, and being beneficial to improving the reliability of use of the battery cell. In addition, along the second direction, the second connecting sub - part has a large size, which is beneficial to increasing the welding area between the second connecting sub - part and the transition part, improving the current - carrying capacity at the connection between the first connecting part and the transition part, increasing the current - carrying capacity of the first pole piece, and improving the fast - charging performance and reliability of use of the battery cell.

[0039] In some embodiments, along the first direction, the first connecting part is spaced apart from the active material layer.

[0040] By adopting the technical solution of this embodiment, the first connecting part does not contact the active species layer, reducing the mutual influence between the two and improving the reliability of use of the battery cell.

[0041] In some embodiments, the electrode assembly further includes an insulating member. The insulating member includes a first insulating part that covers the surface of the metal layer facing away from the insulating substrate, and the entire first insulating part is located between the first welding mark and the active material layer.

[0042] By adopting the technical solution of this embodiment, it is beneficial to reduce the risk of poor soldering between the first connecting part and the metal layer, improving the connection reliability between the first connecting part and the metal layer and also being beneficial to increasing the current - carrying capacity.

[0043] In some embodiments, the first insulating part is located between the first connecting part and the active material layer.

[0044] By adopting the technical solution of this embodiment, the first insulating part can support the part of the metal layer located between the first connecting part and the active material layer, reducing damages such as cracks and fractures that occur in this part during the manufacturing process of the battery device, being beneficial to improving the electron - transfer ability of this part, improving the fast - charging performance and reliability of use of the battery cell. In addition, the first insulating part can also insulate this part, reducing the short - circuit risk of the battery cell and improving the reliability of use of the battery cell.

[0045] In some embodiments, the insulating member further includes a second insulating part, and at least part of the second insulating part covers the first welding mark.

[0046] By adopting the technical solution of this embodiment, the second insulating part can prevent components such as tip protrusions and metal debris on the surface of the first welding mark from piercing through the separator and connecting to the second pole piece, reducing the short - circuit risk of the battery cell and improving the reliability of use of the battery cell.

[0047] In some embodiments, along the first direction, one side of the second insulating portion covers the first welding mark, and the other side of the second insulating portion covers at least a part of the first insulating portion.

[0048] By adopting the technical solution of this embodiment, the second insulating portion and the first insulating portion jointly cover the extending portion, and double-layer insulation can be achieved, which is beneficial to reducing the short-circuit risk of the battery cell and improving the use reliability of the battery cell.

[0049] In some embodiments, the electrode assembly further includes an insulating member, the insulating member includes a second insulating portion, and at least a part of the second insulating portion covers the first welding mark.

[0050] By adopting the technical solution of this embodiment, the second insulating portion covers the surface of the first welding mark, which can prevent components such as tip protrusions and metal debris on the surface of the first welding mark from piercing the separator and connecting with the second electrode sheet, reducing the short-circuit risk of the battery cell and improving the use reliability of the battery cell.

[0051] In some embodiments, along the first direction, one side of the second insulating portion covers the first welding mark, and the other side of the second insulating portion covers at least a part of the active material layer.

[0052] By adopting the technical solution of this embodiment, the second insulating portion extends from the first welding mark to the active material layer, and the coverage area of the second insulating portion is wide and the insulation effect is good, which is beneficial to improving the use reliability of the battery cell.

[0053] In some embodiments, the number of metal layers is two, the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector, the number of active material layers is two, and the two active material layers respectively cover the two metal layers; the number of conductive members is two, and the first connection portions of the two conductive members are respectively welded to the surfaces of the two metal layers facing away from the insulating substrate to form two first welding marks; the number of insulating members is two, and the second insulating portions of the two insulating members respectively cover at least a part of the two first welding marks.

[0054] By adopting the technical solution of this embodiment, the first connection portions of the two conductive members are respectively welded to the metal layers located on opposite sides of the insulating substrate, and the second connection portions of the two conductive members are located on the side of the protruding portion facing away from the main body portion, so that the two metal layers can be directly connected by the second connection portions of the two conductive members, thereby breaking the insulation limitation of the insulating substrate, effectively improving the conductivity of the first electrode sheet, improving the fast charging performance of the battery cell, reducing the heat generation of the battery cell, and improving the use reliability of the battery cell metal layer.

[0055] In some embodiments, the second insulating portion includes a first part and a second part connected to each other. The first part covers at least a portion of the main body portion. Along the direction of the main body portion towards the protruding portion, the second part protrudes from the main body portion, and the second part is located on the side of the protruding portion along the second direction.

[0056] By adopting the technical solution of this embodiment, along the direction of the main body portion pointing to the protruding portion, components such as metal debris at the end face of the main body portion facing the protruding portion can be located between the second parts of the two insulating members, which can reduce the risk of metal debris falling into the electrode assembly and is beneficial to reducing the short-circuit risk.

[0057] In some embodiments, the second parts of the two insulating members are in contact with each other.

[0058] By adopting the technical solution of this embodiment, after the second parts of the two insulating members are in contact with each other, components such as metal debris at the end face of the main body portion facing the protruding portion can be covered, making it difficult for components such as metal debris to fall into the electrode assembly and better reducing the short-circuit risk of the battery cell.

[0059] In some embodiments, the second connecting portions of the two conductive members are welded to form a second weld mark.

[0060] By adopting the technical solution of this embodiment, the second connecting portions of the two conductive members can connect the metal layers on the opposite sides of the insulating substrate, thereby breaking the insulation limitation of the insulating substrate, effectively improving the conductivity of the first pole piece, improving the fast charging performance of the battery cell, reducing the heat generation of the battery cell, and improving the use reliability of the battery cell.

[0061] In some embodiments, the second insulating portion covers the second weld mark. Along the direction of the main body portion pointing to the protruding portion, the second insulating portion protrudes from the edge of the second weld mark facing away from the main body portion.

[0062] By adopting the technical solution of this embodiment, the second insulating portion can completely cover the second weld mark, preventing components such as tip protrusions and metal debris on the second weld mark from piercing the separator and connecting to the second pole piece, reducing the short-circuit risk, and improving the use reliability of the battery cell.

[0063] In some embodiments, the electrode assembly includes a second pole piece having a polarity opposite to that of the first pole piece. The second pole piece includes a main body functional portion and a pole ear portion. The pole ear portion protrudes from the main body functional portion along the first direction; along the direction of the main body portion pointing to the protruding portion, the main body functional portion protrudes from the end face of the insulating member facing the active material layer, and the main body functional portion does not protrude from the end face of the insulating member away from the active material layer.

[0064] By adopting the technical solution of this embodiment, the insulating member can prevent the burrs at the end face of the main functional part of the second pole piece close to the pole ear part from piercing through the separator and connecting with the first pole piece, reducing the short-circuit risk between the first pole piece and the second pole piece, and being beneficial to improving the use reliability of the battery cell.

[0065] In some embodiments, the distance between the first welding mark and the active material layer is S1, where 0.3 mm ≤ S1 ≤ 5 mm. Optionally,

[0066] 0.5 mm ≤ S1 ≤ 2.8 mm.

[0067] By adopting the technical solution of this embodiment, the distance between the active material layer and the first welding mark is more reasonable, which can better balance the connection reliability of the conductive member and the energy density of the battery cell.

[0068] In some embodiments, the current collector further includes a conductive protective layer, at least part of the conductive protective layer is located between the active material layer and the metal layer, and along the first direction, the conductive protective layer and the first welding mark are arranged at intervals.

[0069] By adopting the technical solution of this embodiment, the first connecting part will not be welded to the conductive protective layer, which can reduce risks such as false soldering and is beneficial to improving the welding reliability between the first connecting part and the metal layer.

[0070] In some embodiments, the electrode assembly includes a second pole piece with a polarity opposite to that of the first pole piece. The second pole piece includes a main functional part and a pole ear part, and the pole ear part protrudes from the main functional part along the first direction; along the direction from the main body part to the protruding part, the main functional part protrudes from the end of the main body part facing the protruding part.

[0071] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional part of the second pole piece facing the pole ear part correspond to the hollow area where the main body part does not extend out of the protruding part, which can also reduce the short-circuit risk of the battery cell and improve the use reliability of the battery cell.

[0072] In some embodiments, the current collector further includes a conductive protective layer, and at least part of the conductive protective layer is located between the active material layer and the metal layer.

[0073] By adopting the technical solution of this embodiment, the conductive protective layer can separate the active material layer and the metal layer and play a protective role for the metal layer, reducing risks such as cracks generated in the metal layer due to rolling the active material layer, and being beneficial to improving the current-carrying capacity of the metal layer.

[0074] In some embodiments, along the direction from the main body part to the protruding part, the conductive protective layer protrudes from the end face of the active material layer facing the protruding part.

[0075] By adopting the technical solution of this embodiment, the conductive protective layer can completely separate the active material layer and the metal layer, the conductive protective layer has better protection ability for the metal layer, the current-carrying capacity of the first electrode is better, which is beneficial to improving the fast charging performance and service reliability of the battery cell.

[0076] In some embodiments, along the direction from the main body portion to the protruding portion, the protruding distance of the conductive protective layer protruding from the end face of the active material layer facing the protruding portion ranges from 0.3 mm to 0.8 mm.

[0077] By adopting the technical solution of this embodiment, the current-carrying capacity and energy density of the battery cell can be better balanced.

[0078] In some embodiments, the main body portion includes a transition portion and a conductive portion. The transition portion is connected between the protruding portion and the conductive portion. The conductive portion is covered with an active material layer, and the transition portion is not covered with an active material layer; the transition portion is connected to the conductive member; at least part of the thickness of the conductive portion is less than the thickness of the transition portion.

[0079] By adopting the technical solution of this embodiment, the transition portion has a larger thickness and better current-carrying capacity, which is beneficial to improving the current-carrying capacity of the first electrode, reducing the heat generation of the battery cell, and is beneficial to improving the fast charging performance and service reliability of the battery cell.

[0080] In some embodiments, the conductive portion includes a first sub-portion and a second sub-portion. The first sub-portion is connected between the second sub-portion and the transition portion. The first sub-portion and the second sub-portion are covered with an active material layer. The thickness of the first sub-portion is greater than the thickness of the second sub-portion, and the thickness of the transition portion is greater than or equal to the thickness of the first sub-portion.

[0081] By adopting the technical solution of this embodiment, the current-carrying capacity of the first sub-portion close to the transition portion is greater than that of the second sub-portion far from the transition portion, which can reduce the restriction on the current, improve the current-carrying capacity of the first electrode, reduce the heat generation of the battery cell, and is beneficial to improving the service reliability of the battery cell.

[0082] In some embodiments, the current collector further includes a conductive protective layer. The conductive protective layer includes a first protective portion and a second protective portion. The first protective portion is located between the first sub-portion and the active material layer, and the second protective portion is located between the second sub-portion and the active material layer; wherein, the thickness of the first protective portion is less than the thickness of the second protective portion, and the thickness of the third protective portion is less than or equal to the thickness of the first protective portion.

[0083] By adopting the technical solution of this embodiment, the surface of the conductive protective layer facing away from the insulating substrate is close to a plane, which is beneficial to reducing the rolling damage and improving the current-carrying capacity of the metal layer; in addition, the problem of winding bulging of the current collector can also be reduced.

[0084] In some embodiments, the conductive protective layer further includes a third protective portion that covers the surface of the transition portion facing away from the insulating substrate, and the thickness of the third protective portion is less than or equal to the thickness of the first protective portion.

[0085] By adopting the technical aspect of this embodiment, the setting of the third protective portion can make the conductive protective layer protrude from the active material layer, so that the active material layer and the metal layer can be better separated. In addition, the thickness of the third protective portion is not too large, which is beneficial to reducing material waste and saving the manufacturing cost of the battery cell.

[0086] In some embodiments, the thickness of the protruding portion is greater than or equal to the thickness of the transition portion.

[0087] By adopting the technical solution of this embodiment, the protruding portion has a relatively thick thickness, which can improve the current-carrying capacity of the protruding portion, is beneficial to improving the current-carrying capacity of the first electrode plate, reducing the heat generation of the battery cell, and is beneficial to improving the fast charging performance and use reliability of the battery cell.

[0088] In a second aspect, a battery device is provided, including the battery cell of the above embodiment.

[0089] The battery device of the embodiment of the present application adopts the above battery cell. The battery cell has good fast charging performance and good use reliability, which is beneficial to improving the fast charging performance of the battery device and also beneficial to improving the use reliability of the battery device.

[0090] In a third aspect, an electrical device is provided, including the battery device of the above embodiment.

[0091] The battery device of the embodiment of the present application adopts the above battery device. The battery device has good fast charging performance and good use reliability, which is beneficial to improving the endurance of the electrical device and also beneficial to improving the use reliability of the electrical device.

[0092] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. Description of the Drawings

[0093] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0094] Figure 1Schematic diagram of the structure of a vehicle provided by some embodiments of the present application.

[0095] Figure 2 Exploded schematic diagram of a battery device provided by some embodiments of the present application.

[0096] Figure 3 Exploded schematic diagram of a battery cell provided by some embodiments of the present application.

[0097] Figure 4 Schematic diagram of the structure of an electrode assembly provided by some embodiments of the present application.

[0098] Figure 5 It is a sectional view along the Figure 4 A-A line in

[0099] Figure 6 Schematic diagram of the structure of a first pole piece provided by some embodiments of the present application.

[0100] Figure 7 It is a sectional view along the Figure 6 B-B line in

[0101] Figure 8 It is a Figure 6 partial enlarged view at C in

[0102] Figure 9 Schematic diagram of the structure of the first pole piece after hiding the conductive member provided by some embodiments of the present application.

[0103] Figure 10 It is a Figure 9 partial enlarged view at D in

[0104] Figure 11 Schematic diagram of the structure of a first pole piece provided by some other embodiments of the present application.

[0105] Figure 12 It is a Figure 11 partial enlarged view at E in

[0106] Figure 13 It is a Figure 11 schematic diagram of the structure of the first pole piece shown after hiding the conductive member.

[0107] Figure 14 It is a Figure 13 partial enlarged view at F in

[0108] Figure 15 Schematic diagram of the structure of a first pole piece provided by some other embodiments of the present application.

[0109] Figure 16 It is a sectional view along the Figure 15 H-H line in

[0110] Figure 17 A sectional view taken along line I-I in Figure 15 .

[0111] Figure 18 Schematic structural diagram of a first pole piece provided by some other embodiments of the present application.

[0112] Figure 19 Is Figure 18 a partially enlarged view at J in

[0113] Figure 20 Schematic structural diagram of a first pole piece provided by some other embodiments of the present application.

[0114] Figure 21 A sectional view taken along line K-K in Figure 20 .

[0115] Figure 22 Schematic structural diagram of a second insulating part provided by some embodiments of the present application.

[0116] Figure 23 A sectional view taken along line N-N in Figure 22 .

[0117] Wherein, each reference numeral in the figure:

[0118] 1000, vehicle; 1100, battery device; 1200, controller; 1300, motor; 100, battery cell; 101, electrode assembly; 1, first pole piece; 10, current collector; 11, insulating substrate; 12, metal layer; 121, main body part; 1211, transition part; 1212, conductive part; 12121, first sub-part; 12122, second sub-part; 122, protruding part; 1221, first protruding sub-part; 1222, second protruding sub-part; 13, conductive protective layer; 131, first protective part; 132, second protective part; 133, third protective part; 20, active material layer; 21, first active material part; 22, second active material part; 30, conductive member; 31, first connection part; 311, first connection sub-part; 312, second connection sub-part; 32, second connection part; 40, insulating part; 41, first insulating part; 42, second insulating part; 421, first part; 422, second part; 423, insulating base layer; 424, adhesive layer; 51, first welding mark; 511, first welding mark part; 5111, first welding mark sub-part; 5112, second welding mark sub-part; 512, second welding mark part; 52, second welding mark; 2, second pole piece; 210, main body functional part; 220, pole ear part; 3, separator; 200, outer shell; 201, end cover; 2011, electrode lead-out part; 202, housing; 300, box body; 301, first box body part; 302, second box body part. Detailed implementation manners

[0119] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the following further details the present application in conjunction with the accompanying Figures 1 - 23 drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0120] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above description of the drawings are intended to cover non-exclusive inclusion.

[0121] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0122] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0123] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces). The meaning of "several" is one or more, unless otherwise specifically defined.

[0124] In the description of the embodiments of the present application, technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present application.

[0125] In the description of the embodiments of the present application, unless otherwise clearly specified or limited, technical terms such as "installation", "connection", "attachment", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0126] In the description of the embodiments of the present application, unless otherwise clearly specified or limited, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0127] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging so as to continue to be used.

[0128] The battery cell can include but is not limited to lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-metal hydride battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0129] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a multi-prismatic battery cell, and the multi-prismatic battery cell is, for example, a hexagonal-prismatic battery cell, etc.

[0130] The battery device mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0131] In some embodiments, the battery device can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0132] In some embodiments, the battery device can be a battery pack, and the battery pack includes a box body and battery cells, and the battery cells or the battery module are accommodated in the box body.

[0133] In some embodiments, the box body can be part of the chassis structure of a vehicle. For example, part of the box body can become at least part of the floor of the vehicle, or part of the box body can become at least part of the cross beam and longitudinal beam of the vehicle.

[0134] In some embodiments, the battery device can be an energy storage device. The energy storage device includes an energy storage container, an energy storage electrical cabinet, etc.

[0135] A battery cell generally includes an electrode assembly and a housing, and the electrode assembly is accommodated in the housing. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode.

[0136] In some embodiments, the electrode assembly further includes a separator, which is disposed between the positive electrode and the negative electrode, and can play a role in preventing short circuit between the positive and negative electrodes, and at the same time allow active ions to pass through.

[0137] The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum plastic film, etc.

[0138] In some embodiments, the positive electrode can be a positive electrode sheet, and the positive electrode sheet can include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0139] The current collector (positive electrode current collector or negative electrode current collector) usually adopts a metal material, such as metal aluminum foil and metal copper foil. However, pure metal foils are prone to generating metal burrs, and the burrs penetrate the separator, resulting in an internal short circuit, posing a greater risk of fire and explosion for the battery cell.

[0140] In order to reduce the short circuit risk inside the battery cell, a current collector is proposed. The current collector includes an insulating matrix and a metal layer covering the surface of the insulating matrix, and the active material layer covers the surface of the metal layer facing away from the insulating matrix. The thickness of the metal layer is usually set to be small, so that during the process of foreign objects piercing the electrode sheet, the burrs generated by the metal layer are small and not easily penetrate the separator. Among them, the metal layer usually includes a main body portion and a protruding portion protruding outside the main body portion, and the protruding portion is connected to the electrode lead-out portion on the housing for outputting or inputting the electrical energy of the battery cell. However, the thickness of the metal layer is small, the current-carrying area between the protruding portion and the main body portion is small, and the current-carrying capacity between the protruding portion and the main body portion is not good, which is prone to heat generation and is not conducive to improving the fast charging performance of the battery cell.

[0141] Based on this, the embodiments of the present application provide a technical solution, in which the sum of the sizes of the first protruding sub-portions of all the protruding portions is more than 0.5 times the size of the main body portion, increasing the current-carrying area between all the protruding portions and the main body portion, improving the current-carrying capacity between all the protruding portions and the main body portion, reducing the heat generation of the battery cell, and being beneficial to improving the fast charging performance and use reliability of the battery cell.

[0142] The battery cell described in the embodiments of the present application is applicable to a battery device and an electrical device using the battery device.

[0143] The battery device disclosed in the embodiments of the present application can be used for an electrical device using the battery device as a power source or various energy storage systems using the battery device as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spaceship, and the like.

[0144] For the convenience of description, the following embodiments will be described by taking the electrical device as a vehicle as an example.

[0145] As Figure 1 shown, a battery device 1100 is disposed inside the vehicle 1000, and the battery device 1100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery device 1100 can be used for power supply of the vehicle 1000. For example, the battery device 1100 can be used as an operating power source of the vehicle 1000.

[0146] The vehicle 1000 may further include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0147] In some embodiments of the present application, the battery device 1100 can not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0148] As Figure 2 shown, the battery device 1100 includes a box body 300 and a battery cell 100, and the battery cell 100 is accommodated in the box body 300.

[0149] The housing 300 is used to accommodate the battery cells 100, and the housing 300 can have various structures. In some embodiments, the housing 300 can include a first housing part 301 and a second housing part 302. The first housing part 301 and the second housing part 302 cover each other, and the first housing part 301 and the second housing part 302 jointly define a receiving space for accommodating the battery cells 100. The second housing part 302 can be a hollow structure with an open end, and the first housing part 301 is a plate-like structure. The first housing part 301 covers the open side of the second housing part 302 to form the housing 300 with a receiving space; both the first housing part 301 and the second housing part 302 can also be hollow structures with an open side, and the open side of the first housing part 301 covers the open side of the second housing part 302 to form the housing 300 with a receiving space. Of course, the first housing part 301 and the second housing part 302 can have various shapes, such as a cylinder, a cuboid, etc.

[0150] To improve the sealing performance after the connection between the first housing part 301 and the second housing part 302, a sealing member can also be provided between the first housing part 301 and the second housing part 302, such as sealant, sealing ring, etc.

[0151] Assuming that the first housing part 301 covers the top of the second housing part 302, the first housing part 301 can also be called the upper cover, and the second housing part 302 can also be called the lower housing 300.

[0152] In the battery device 1100, there can be one or more battery cells 100. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection means that there are both series and parallel connections among the multiple battery cells 100.

[0153] The multiple battery cells 100 can be directly connected in series, in parallel, or in a hybrid connection together, and then the whole formed by the multiple battery cells 100 is accommodated in the housing 300; of course, it can also be that the multiple battery cells 100 are first connected in series, in parallel, or in a hybrid connection to form battery modules, and then the multiple battery modules are connected in series, in parallel, or in a hybrid connection to form a whole and are accommodated in the housing 300.

[0154] Exemplarily, the battery cell 100 can be the smallest unit that makes up the battery device 1100.

[0155] Such as Figure 3As shown, in some embodiments, the battery cell 100 includes a housing 200 and an electrode assembly 101 accommodated within the housing 200. The electrode assembly 101 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 100, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. Optionally, the electrode assembly 101 further includes a separator 3 disposed between the positive electrode and the negative electrode. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes and at the same time allow the active ions to pass through.

[0156] The housing 200 is used to encapsulate components such as the electrode assembly 101 and the electrolyte.

[0157] In some embodiments, the housing 200 includes a housing body 202 and an end cap 201. The housing body 202 has an opening, and the end cap 201 is used to cover the opening.

[0158] The housing body 202 is a component for cooperating with the end cap 201 to form an internal cavity of the battery cell 100. The formed internal cavity can be used to accommodate the electrode assembly 101, the electrolyte, and other components.

[0159] The housing body 202 and the end cap 201 can be independent components. Exemplarily, an opening can be provided on the housing body 202, and the end cap 201 is covered at the opening to form an internal cavity of the battery cell 100.

[0160] The housing body 202 can be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing body 202 can be determined according to the specific shape and size of the electrode assembly 101. The material of the housing body 202 can be various. For example, the material of the housing body 202 includes but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum plastic film, steel plastic film, etc.

[0161] The shape of the end cap 201 can be adapted to the shape of the housing body 202 to cooperate with the housing body 202. The material of the end cap 201 can be the same as or different from the material of the housing body 202. Optionally, the end cap 201 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 201 is not easily deformed when being squeezed or collided, enabling the battery cell 100 to have higher structural strength and improved reliability.

[0162] The end cap 201 is connected to the housing body 202 by welding, bonding, clamping or other means.

[0163] The housing 202 can be open at one end or both ends. In some examples, the housing 202 can be a structure with an opening on one side, and the end cap 201 is provided as one and covers the housing 202. In other examples, the housing 202 can also be a structure with openings on both sides, and the end caps 201 are provided as two, and the two end caps 201 respectively cover the two openings of the housing 202.

[0164] In some embodiments, the battery cell 100 includes electrode lead-out portions 2011. The number of the electrode lead-out portions 2011 is two, and the two electrode lead-out portions 2011 are respectively connected to the positive electrode sheet and the negative electrode sheet to output or input the electric energy of the battery cell 100.

[0165] In some embodiments, the battery cell 100 further includes an electrolyte accommodated in the outer shell 200. The electrolyte functions to conduct ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like or solid.

[0166] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0167] In some embodiments, the electrolyte salt may include 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 difluorooxalate borate, lithium bis(oxalate) borate, lithium difluoro bis(oxalate) phosphate, and lithium tetrafluorooxalate phosphate.

[0168] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl 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 ethyl sulfone, and diethyl sulfone.

[0169] The solvent can also be an ether solvent. The ether solvent can 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.

[0170] In some embodiments, the gel-like electrolyte includes a polymer as the skeletal network of the electrolyte, combined with an ionic liquid-lithium salt.

[0171] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0172] As an example, the polymer solid electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single-ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0173] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorus sulfur, argyrodite), amorphous sulfide), and one or more of a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0174] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to the polymer solid electrolyte.

[0175] Referring to Figure 4 and Figure 5 and , the electrode assembly 101 of the embodiment of the present application includes a first pole piece 1 and a second pole piece 2 with opposite polarities.

[0176] Exemplarily, one of the first pole piece 1 and the second pole piece 2 is a positive electrode piece, and the other is a negative electrode piece.

[0177] In some embodiments, the positive electrode piece may include a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector.

[0178] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material layer is provided on any one or both of the two opposite surfaces of the positive electrode current collector.

[0179] As an example, the positive electrode current collector can be made of carbon, metal foil, or composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, titanium, aluminum or stainless steel with silver surface treatment, etc. can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0180] As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. Other conventional materials that can be used as the positive electrode active material layer of the battery device 1100 may also be used for the positive electrode active material. These positive electrode active materials may be used alone or in combination of two or more. Examples of the lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO4 (which may also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and at least one of a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which may also be abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which may also be abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which may also be abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which may also be abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which may also be abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and their modified compounds, etc.

[0181] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector.

[0182] As an example, the negative electrode current collector can be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrodes, nickel, or titanium, etc. can be used. The foam metal can be nickel foam, copper foam, aluminum foam, foam alloy, or foam carbon, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0183] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material can be a negative electrode active material known in the art for the battery cell 100. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials can include at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials can include at least one of elemental tin, tin oxides, and tin alloys. The negative electrode active material of the present application can also use other conventional materials that can be used as the negative electrode active material of the battery device 1100. These negative electrode active materials can be used alone or in combination of two or more.

[0184] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0185] In some embodiments, the electrode assembly 101 further includes a separator 3, and the separator 3 is used to separate the first electrode sheet 1 and the second electrode sheet 2. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes, and at the same time allow active ions to pass through.

[0186] In some embodiments, the separator 3 includes a separator membrane. The separator membrane of the present application can be any known porous structure separator membrane with good chemical stability and mechanical stability.

[0187] As an example, the main materials of the separator membrane can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator membrane can be a single-layer film or a multi-layer composite film. When the separator membrane is a multi-layer composite film, the materials of each layer can be the same or different. The separator 3 can be a separate component located between the positive and negative electrodes, or can be attached to the surfaces of the positive and negative electrodes.

[0188] In some embodiments, the separator 3 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet, and at the same time plays the role of transporting ions and isolating the positive and negative electrodes.

[0189] In some embodiments, the electrode assembly 101 has a wound structure. Exemplarily, both the first electrode tab 1 and the second electrode tab 2 are strip-shaped structures, and the first electrode tab 1, the separator 3, and the second electrode tab 2 are wound into a wound structure.

[0190] In some embodiments, the electrode assembly 101 has a stacked structure.

[0191] As an example, multiple first electrode tabs 1 and multiple second electrode tabs 2 can be respectively provided, and the multiple first electrode tabs 1 and the multiple second electrode tabs 2 are alternately stacked.

[0192] As an example, multiple first electrode tabs 1 can be provided, and the second electrode tab 2 is folded to form multiple folded segments arranged in a stacked manner, and one first electrode tab 1 is clamped between adjacent folded segments.

[0193] As an example, both the first electrode tab 1 and the second electrode tab 2 are folded to form multiple folded segments arranged in a stacked manner.

[0194] As an example, multiple separators 3 can be provided and are respectively disposed between any adjacent first electrode tab 1 or second electrode tab 2.

[0195] As an example, the separator 3 can be continuously provided and is disposed between any adjacent first electrode tab 1 or second electrode tab 2 by means of folding or winding.

[0196] In some embodiments, the shape of the electrode assembly 101 can be cylindrical, flat, prismatic, or the like.

[0197] Please refer to Figures 6 - 10As shown, in some embodiments, a battery cell 100 is provided. The battery cell 100 includes a housing 200 and an electrode assembly 101. The housing 200 is provided with an electrode lead-out portion 2011. At least a part of the electrode assembly 101 is accommodated in the housing 200. The electrode assembly 101 includes a first electrode tab 1, and the first electrode tab 1 includes a conductive member 30, a current collector 10, and an active material layer 20. The conductive member 30 is connected to the electrode lead-out portion 2011. The current collector 10 includes an insulating matrix 11 and a metal layer 12. The insulating matrix 11, the metal layer 12, and the active material layer 20 are stacked along the thickness direction of the current collector 10. At least a part of the metal layer 12 is located between the insulating matrix 11 and the active material layer 20. The metal layer 12 includes a main body portion 121 and at least one protruding portion 122. The protruding portion 122 extends outward from an end of the main body portion 121 in a first direction, and the first direction is perpendicular to the thickness direction of the current collector 10. Each protruding portion 122 is connected to the conductive member 30. At least a part of the main body portion 121 is covered with the active material layer 20, and at least a part of the protruding portion 122 is not covered with the active material layer 20. The protruding portion 122 includes a first protruding sub-portion 1221 connected to the main body portion 121. Along a second direction, the sum of the sizes l1 of the first protruding sub-portions 1221 of all the protruding portions 122 is more than 0.5 times the size l2 of the main body portion 121, where the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0198] A part of the electrode assembly 101 is located inside the housing 200; another part is located outside the housing 200, or the entire electrode assembly 101 is located inside the housing 200.

[0199] In some examples, the first electrode tab 1 is a positive electrode tab, the current collector 10 is a positive current collector, the positive current collector adopts a composite current collector structure, and the active material layer 20 is a positive active material layer; or, the first electrode tab 1 is a negative electrode tab, the current collector 10 is a negative current collector, the negative current collector is a composite current collector structure, and the active material layer 20 is a negative active material layer.

[0200] The conductive member 30 may refer to a component for connecting the electrode lead-out portion 2011 and the current collector 10. The conductive member 30 can adopt copper foil or aluminum foil to facilitate connection with the electrode lead-out portion 2011.

[0201] The electrode lead-out portion 2011 may refer to a conductive component for outputting or inputting electric energy. The electrode lead-out portion 2011 is connected to an external electronic device so that the battery cell 100 outputs or inputs electric energy. The electrode lead-out portion 2011 is also called a terminal post. The electrode lead-out portion 2011 can be provided on the housing 202 or on the end cap 201.

[0202] The electrode lead-out part 2011 is connected to the conductive member 30. The electrode lead-out part 2011 can be directly connected to the conductive member 30. For example, the electrode lead-out part 2011 is directly welded to the conductive member 30. Or, the electrode lead-out part 2011 can be connected to the conductive member 30 through a conductive component (such as a connecting piece, etc.). For example, one end of the conductive component is welded to the conductive member 30, and the other end of the conductive component is welded to the electrode lead-out part 2011.

[0203] The current collector 10 includes a metal layer 12 and an insulating substrate 11. The current collector 10 is a multi-layer structure. The insulating substrate 11 can refer to the component made of an insulating material (such as the above-mentioned polymer base material) in the current collector 10, and the metal layer 12 can refer to the component made of the above-mentioned metal material in the current collector 10.

[0204] The surface of the insulating substrate 11 is covered with a metal layer 12, and the surface of the metal layer 12 facing away from the insulating substrate 11 is covered with an active material layer 20, so that the insulating substrate 11, the metal layer 12, and the active material layer 20 are stacked, and the stacking direction of the insulating substrate 11, the metal layer 12, and the active material layer 20 is the thickness direction of the current collector 10 (see the Y direction in Figure 7 ). Among them, the active material layer 20 can be directly covered on the surface of the metal layer 12, or other substances can be covered on the surface of the metal layer 12 and then the active material layer 20 can be covered.

[0205] In some examples, one surface of the insulating substrate 11 is covered with a metal layer 12.

[0206] In some examples, both opposite surfaces of the insulating substrate 11 are covered with metal layers 12. Among the two metal layers 12, at least one metal layer 12 has an active material layer 20 covering the surface facing away from the insulating body.

[0207] The first direction can refer to the direction perpendicular to the thickness direction of the current collector 10; the second direction can refer to the direction perpendicular to the thickness direction and the first direction of the current collector 10.

[0208] In some examples, the electrode assembly 101 is a wound structure. When the first electrode sheet 1 is in the unfolded state, the first direction can refer to the width direction of the first electrode sheet 1 (see the Z direction in Figure 6 ); the second direction can refer to the length direction of the first electrode sheet 1 (see the X direction in Figure 6 ). When the first electrode sheet 1 is in the wound state, the second direction can also refer to the winding direction of the first electrode sheet 1 (see the direction indicated by the arrow V in Figure 4 ).

[0209] In some examples, the electrode assembly 101 is a stacked structure, and the first direction can be the width direction of the first electrode sheet 1 (see Figure 6in the Z direction), the second direction can refer to the length direction of the first pole piece 1 (which can refer to Figure 6 the X direction in

[0210] The metal layer 12 includes a main body portion 121 and a protruding portion 122. The main body portion 121 is the main part of the metal layer 12; the protruding portion 122 extends outward from the end of the main body portion 121 along the first direction. The protruding portion 122 can be a protruding structure formed at the edge of the main body portion 121 along the first direction; wherein, along the second direction, the dimension l3 of the protruding portion 122 is smaller than the dimension l2 of the main body portion 121, so that the protruding portion 122 and the main body portion 121 form a stepped structure. The number of the protruding portions 122 can be one or more, and multiple protruding portions 122 are arranged at intervals along the second direction.

[0211] The active material layer 20 can cover a part of the main body portion 121, or can cover the entire main body portion 121; the active material layer 20 can also cover the entire protruding portion 122, or can cover a part of the protruding portion 122. For example, the root of the protruding portion 122 close to the main body portion 121 is covered with the active material layer 20.

[0212] The first protruding sub-portion 1221 can refer to the root of the protruding portion 122 close to the main body portion 121; exemplarily, along the second direction, the dimension l3 of the first protruding sub-portion 1221 can refer to the length of the boundary line (which can refer to the dotted line Q) between the protruding portion 122 and the main body portion 121. The dimension l3 of each first protruding sub-portion 1221 along the second direction can be the same or different.

[0213] In some examples, along the first direction, the dimension of the protruding portion 122 in the second direction does not change, that is, the protruding portion 122 is a structure with equal length.

[0214] In some examples, along the direction from the main body portion 121 to the protruding portion 122, the dimension of the protruding portion 122 in the second direction can gradually increase or gradually decrease. Among them, the direction from the main body portion 121 to the protruding portion 122 can refer to Figure 6 the direction indicated by the arrow Z in

[0215] When the number of the protruding portions 122 is one, l1 = l3; when the number of the protruding portions 122 is multiple, along the second direction, the dimension l2 of the main body portion 121 is equal to the sum of the dimensions l3 of the first protruding sub-portions 1221 of all the protruding portions 122; exemplarily, the number of the protruding portions 122 is N, and the dimension l3 of the first protruding sub-portion 1221 of each protruding portion 122 is equal, l1 = N * l3, where N ≥ 2.

[0216] In the second direction, the sum of the sizes l1 of the first protruding sub-parts 1221 of all the protruding parts 122 is more than 0.5 times the size l2 of the main body part 121. It can be understood that 0.5 ≤ l1 / l2 < 1, so that in the second direction, the sum of the sizes l1 of the first protruding sub-parts 1221 of all the protruding parts 122 is greater than or equal to more than half of the size l2 of the main body part 121, increasing the total current-carrying area between the protruding part 122 and the main body part 121 and improving the total current-carrying capacity between the protruding part 122 and the main body part 121. Exemplarily, the sum of the sizes l1 of the first protruding sub-parts 1221 of all the protruding parts 122 in the second direction can be increased by increasing the number of the protruding parts 122, or the sum of the sizes l1 of the first protruding sub-parts 1221 of all the protruding parts 122 in the second direction can also be increased by increasing the size l3 of a single first protruding sub-part 1221 in the second direction.

[0217] In some examples, the value of l1 / l2 can be 0.5 and any value between 0.5 and 1. Exemplarily, the value of l1 / l2 can be, but is not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99.

[0218] In some examples, one end of the conductive member 30 is connected to the electrode lead-out, and the other end of the conductive member 30 is connected to the protruding part 122, thereby electrically connecting the metal layer 12 and the electrode lead-out part 2011, so that current can flow into or out of the battery cell 100 through the electrode lead-out part 2011, the conductive member 30 and the protruding part 122 of the metal layer 12, realizing the charge and discharge of the battery cell 100.

[0219] In some examples, the conductive member 30 is directly connected to the surface of the protruding part 122 facing away from the insulating substrate 11, and the conductive member 30 is not directly connected to the main body part 121.

[0220] In some examples, the surface of the protruding part 122 facing away from the insulating substrate 11 and the surface of the main body part 121 facing away from the insulating substrate 11 are both directly connected to the conductive member 30, thereby increasing the current-carrying area between the conductive member 30 and the metal layer 12, which is beneficial to improving the current-carrying capacity of the first electrode sheet 1 and beneficial to improving the fast charging performance of the battery cell 100.

[0221] In some examples, the conductive member 30 and the electrode lead-out part 2011 can be connected by welding or conductive adhesive, etc., to realize the connection between the conductive member 30 and the electrode lead-out part 2011.

[0222] In some examples, the conductive member 30 is connected to the protruding part 122 by welding or conductive adhesive, etc., to realize the connection between the conductive member 30 and the protruding part 122.

[0223] For the battery cell 100 according to the embodiment of the present application, when the battery cell 100 is in normal use, the electrode lead-out part 2011 is used to input or output electric energy, realizing the charging and discharging of the battery cell 100; and along the second direction, the sum of the sizes of the first protruding sub-parts 1221 of all the protruding parts 122 is more than 0.5 times the size of the main body part 121, increasing the total current-carrying area between the protruding parts 122 and the main body part 121, improving the total current-carrying capacity between the protruding parts 122 and the main body part 121, being beneficial to improving the current-carrying capacity of the first electrode sheet 1, reducing the heat generation of the battery cell 100, being beneficial to improving the charging efficiency and discharging efficiency of the battery cell 100, and improving the fast charging performance of the battery cell 100. In addition, the current collector 10 adopts a composite structure of an insulating matrix 11 and a metal layer 12. Compared with the current collector 10 made of pure metal, the thickness of the metal layer 12 is small, and the burrs generated by the metal layer 12 during the manufacturing process of the current collector 10 are small, reducing the risk of internal short circuit of the battery cell 100 and being beneficial to improving the use reliability of the battery cell 100; therefore, the battery cell 100 according to the embodiment of the present application can better balance the current-carrying capacity and the use reliability.

[0224] In some embodiments, along the second direction, the sum of the sizes l1 of the first protruding sub-parts 1221 of all the protruding parts 122 is more than 0.6 times the size l2 of the main body part 121.

[0225] It can be understood that 0.6 ≤ l1 / l2 < 1, such that along the second direction, the sum of the sizes l1 of the first protruding sub-parts 1221 of all the protruding parts 122 exceeds half of the size l2 of the main body part 121, effectively increasing the total current-carrying area between the protruding parts 122 and the main body part 121 and improving the total current-carrying capacity between the protruding parts 122 and the main body part 121.

[0226] By adopting the technical solution of this embodiment, the total current-carrying area between the protruding parts 122 and the main body part 121 can be effectively increased, the total current-carrying capacity between the protruding parts 122 and the main body part 121 can be improved, the current-carrying capacity of the first electrode sheet 1 can be effectively improved, the heat generation of the battery cell 100 can be reduced, and it is beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0227] In some embodiments, the active material layer 20 includes a first active material part 21 and a second active material part 22. The first active material part 21 is connected to the end of the second active material part 22 facing the protruding part 122, and the thickness of the first active material part 21 is less than the thickness of the second active material part 22.

[0228] In some examples, the first active material portion 21 is located at the edge of the active material layer 20 facing the convex portion 122. Both the first active material portion 21 and the second active material portion 22 cover the conductive portion 1212. The first active material portion 21 may generally have an equal-thickness structure, and the thickness of the first active material portion 21 is less than that of the second active material portion 22, such that the first active material portion 21 and the second active material portion 22 form a stepped structure; in other examples, the thickness of the first active material portion 21 may also decrease stepwise, such that the first active material portion 21 is a stepped structure; or, along the direction of the main body portion 121 facing the convex portion 122, the thickness of the first active material portion 21 may also decrease slowly, such that the thickness of the first active material portion 21 decreases slowly, and the outer shape of the first active material portion 21 is more rounded or smooth.

[0229] During the forming process of the first electrode tab 1, the active material layer 20 can be roll-pressed to compact the active material layer 20; and the setting of the first active material portion 21 can reduce the roll pressure on the edge of the active material layer 20 and reduce the risk of cracking at the edge of the active material layer 20.

[0230] In some embodiments, the conductive member 30 includes a first connection portion 31 and at least one second connection portion 32. The first connection portion 31 and the second connection portion 32 are arranged along a first direction, the first connection portion 31 and the second connection portion 32 are connected, the second connection portion 32 is connected to the electrode lead-out portion 2011, the first connection portion 31 is welded to the surface of the metal layer 12 facing away from the insulating substrate 11 to form a first welding mark 51, and the second connection portion 32 is located at the side of the convex portion 122 facing away from the main body portion 121; along the first direction, the first welding mark 51 is located at the side of the active material layer 20 facing the convex portion 122.

[0231] The first connection portion 31 may refer to the part where the conductive member 30 is welded to the metal layer 12, and the second connection portion 32 may refer to the part where the conductive member 30 is connected to the electrode lead-out portion 2011.

[0232] In some examples, the first connection portion 31 may cover the metal layer 12 and be welded to the metal layer 12, and the second connection portion 32 may extend from the side of the first connection portion 31 facing away from the active material layer 20 along the first direction to protrude outside the insulating substrate 11, that is, along the thickness direction of the current collector 10, the projection of the first connection portion 31 is located within the projection of the metal layer 12, and the projection of the second connection portion 32 is located outside the projection range of the metal layer 12; in this way, the connection positions of the metal layer 12 and the electrode lead-out portion 2011 on the conductive member 30 are different, which is convenient for connection and can also reduce the mutual influence between the two connections, being beneficial to connection reliability.

[0233] In some cases, when the electrode sheet is wound to form the electrode assembly 101, the insulating matrix 11 insulates and separates two adjacent layers of the metal layer 12, making it difficult for the two adjacent layers of the metal layer 12 to be directly connected across the insulating matrix 11 to transfer current outward. As a result, the current can almost only be transferred outward from the outermost layer of the metal layer 12, resulting in poor conductivity, low fast-charging performance, and easy local overheating, which affects the use reliability of the battery cell 100. In the battery cell 100 of the embodiment of the present application, the first connecting portion 31 of the conductive member 30 is welded to the metal layer 12, and the second connecting portion 32 of the conductive member 30 protrudes outside the insulating matrix 11. In this way, the two adjacent layers of the metal layer 12 can be electrically connected through the second connecting portion 32, thereby breaking the insulation limitation of the insulating matrix 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast-charging performance of the battery cell 100, reducing the heat generation of the battery cell, and improving the use reliability of the battery cell 100.

[0234] When the electrode sheets are stacked to form the electrode assembly 101, the insulating matrix 11 insulates and separates two adjacent metal layers 12, making it difficult for the two adjacent metal layers 12 to be directly connected to transfer current outward. As a result, the current can almost only be transferred outward from the outermost metal layer 12, resulting in poor conductivity, low fast-charging performance, and easy local overheating, which affects the use reliability of the battery cell 100. In the battery cell 100 of the embodiment of the present application, the first connecting portion 31 of the conductive member 30 is welded to the metal layer 12, and the second connecting portion 32 of the conductive member 30 protrudes outside the insulating matrix 11. In this way, the two adjacent metal layers 12 can be electrically connected through the second connecting portion 32, thereby breaking the insulation limitation of the insulating matrix 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast-charging performance of the battery cell 100, reducing the heat generation of the battery cell, and improving the use reliability of the battery cell 100.

[0235] The first connecting portion 31 is stacked on the surface of the metal layer 12 facing away from the insulating matrix 11 and welded to the surface of the metal layer 12 facing away from the insulating matrix 11, and the trace formed by the welding is the first welding mark 51.

[0236] "Along the first direction, the first welding mark 51 is located on the side of the active material layer 20 facing the protruding portion 122". It can be understood that along the first direction, the first welding mark 51 is arranged at an interval from the active material layer 20, so that the part of the metal layer 12 facing the protruding portion 122 where the active material layer 20 is not covered is welded to the first connecting portion 31, so that the first connecting portion 31 will not be welded to the active material layer 20, which is beneficial to reducing the risk of problems such as false soldering, and is beneficial to improving the connection reliability and current-carrying capacity between the metal layer 12 and the conductive member 30; or, the edge of the first welding mark 51 is in contact with the edge of the active material layer 20 facing the protruding portion 122, that is, the first connecting portion 31 is welded to the edge of the active material layer 20, and only the edge of the first welding mark 51 coincides with the active material layer 20, resulting in a small risk of false soldering, which is beneficial to improving the connection reliability between the first connecting portion 31 and the metal layer 12.

[0237] In some examples, the first connecting portion 31 may be welded only to the protruding portion 122.

[0238] In some examples, the first connecting portion 31 is welded to the protruding portion 122, and the first connecting portion 31 is also welded to the part of the main body portion 121 facing the protruding portion 122 where the active material layer 20 is not covered.

[0239] In some examples, the second connecting portion 32 and the electrode lead-out portion 2011 can be connected by direct welding, and can also be welded through a conductive member (such as a connecting piece, etc.). By using the welding method, the connection operation is convenient and the processing and manufacturing are convenient. Of course, the connection can also be achieved by other means.

[0240] By adopting the technical solution of this embodiment, the first connecting portion 31 is welded to the metal layer 12, and the conductive member 30 is connected to the metal layer 12 by welding, which is convenient for the production of the first electrode sheet 1; the thickness of the metal layer 12 is small, and the surface of the metal layer 12 facing away from the insulating substrate 11 is large, which is beneficial to increasing the welding area between the conductive member 30 and the metal layer 12, increasing the current-carrying area between the conductive member 30 and the metal layer 12, being beneficial to improving the current-carrying capacity of the first electrode sheet 1, and improving the fast charging performance of the battery cell 100; the second connecting portion 32 protrudes outside the protruding portion 122, which is convenient for the connection between the second connecting portion 32 and the electrode lead-out portion 2011, and the processing and manufacturing are more convenient; at the same time, the risk of problems such as false soldering between the first connecting portion 31 and the metal layer 12 can also be reduced, which is beneficial to improving the connection reliability between the metal layer 12 and the conductive member 30, and is also beneficial to improving the current-carrying capacity of the first electrode sheet 1, and improving the fast charging performance and service reliability of the battery cell 100.

[0241] In some embodiments, the first welding mark 51 includes a first welding mark portion 511, and the first connecting portion 31 is welded to the surface of the protruding portion 122 facing away from the insulating substrate 11 to form the first welding mark portion 511.

[0242] The first connecting portion 31 is stacked on the surface of the protruding portion 122 facing away from the insulating substrate 11 and welded to the protruding portion 122. The trace formed by the welding is the first welding mark portion 511.

[0243] In some examples, the first connecting portion 31 can be welded to the entire protruding portion 122, or the first connecting portion 31 can be welded to a part of the protruding portion 122, and the other part of the first protruding portion 122 is not welded to the first connecting portion 31.

[0244] By adopting the technical solution of this embodiment, the first connecting portion 31 and the protruding portion 122 are connected by welding. The connection method is simple and convenient for the production of the first pole piece 1. In addition, the first connecting portion 31 and the protruding portion 122 can directly use the first welding mark portion 511 for current conduction, which is beneficial to improving the current conduction ability between the first connecting portion 31 and the protruding portion 122.

[0245] In some embodiments, along the second direction, the first welding mark portion 511 extends from one side edge of the protruding portion 122 to the other side edge of the protruding portion 122.

[0246] Along the first direction, the projection of the first welding mark portion 511 falls within the projection of the protruding portion 122.

[0247] During the production process of the first pole piece 1, the conductive member 30 can be welded to the edge of the equal-length current collector 10 by ultrasonic welding (for example: double-roller continuous ultrasonic welding) or other welding methods, and an equal-width welding mark is formed. Then, the conductive member 30 is cut by laser die-cutting or other cutting methods to form a tab to facilitate connection with the electrode lead-out portion 2011. During the cutting process, first cut along the second direction between the equal-width welding mark and the active material layer 20, then cut towards the equal-width welding mark until leaving the equal-width welding mark, continue to cut a certain distance away from the active material layer 20, then move and cut a certain distance along the second direction, and then cut towards the equal-width welding mark until leaving the equal-width welding mark, and then cut along the second direction, so that a first welding mark portion 511 can be obtained. By repeating this process, multiple first welding mark portions 511 can be obtained.

[0248] By adopting the technical solution of this embodiment, along the second direction, the size L4 of the first welding mark portion 511 is large, which is beneficial to increasing the current conduction area between the first connecting portion 31 and the protruding portion 122, beneficial to improving the current conduction ability between the first connecting portion 31 and the protruding portion 122, beneficial to reducing the heat generation of the battery cell 100, and beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0249] In some embodiments, the protruding portion 122 further includes a second protruding sub-portion 1222. The first protruding sub-portion 1221 is connected between the second protruding sub-portion 1222 and the main body portion 121. Along the second direction, the dimension l3 of the first protruding sub-portion 1221 is greater than the dimension l4 of the second protruding sub-portion 1222. The first welding mark portion 511 includes a first welding mark sub-portion 5111. The first connecting portion 31 is welded to the first protruding sub-portion 1221 to form the first welding mark sub-portion 5111.

[0250] Exemplarily, the protruding portion 122 has a stepped structure. Along the first direction, the protruding portion 122 is divided into two parts. The part close to the main body portion 121 is the first protruding sub-portion 1221, and the part far from the main body portion 121 is the second protruding sub-portion 1222. Along the second direction, the dimension l4 of the second protruding sub-portion 1222 is equal to the length of the boundary line (see the dotted line M) between the first protruding sub-portion 1221 and the second protruding sub-portion 1222. The dimension l4 of each second protruding sub-portion 1222 along the second direction may be the same or different.

[0251] l3 > l4, which is equivalent to increasing the dimension l3 of the first protruding sub-portion 1221 along the second direction, increasing the current-carrying area between the protruding portion 122 and the main body portion 121, improving the current-carrying capacity, and reducing the heat generation of the battery cell 100.

[0252] The first connecting portion 31 is welded to the surface of the first protruding sub-portion 1221 facing away from the insulating substrate 11, and the mark generated by the welding is the first welding mark sub-portion 5111.

[0253] Exemplarily, the first connecting portion 31 can be welded to the side of the first protruding sub-portion 1221 facing the main body portion 121, so that the first welding mark sub-portion 5111 is directly connected to the main body portion 121. In this way, the first connecting portion 31 and the main body portion 121 can directly conduct current through the first welding mark portion 5111, which is beneficial to improving the current-carrying capacity between the first connecting portion 31 and the main body portion 121, reducing the heat generation of the battery cell 100, and improving the fast charging performance and service reliability of the battery cell 100. Of course, the first connecting portion 31 can also be welded to the side of the first protruding sub-portion 1221 facing away from the main body portion 121, so that the first welding mark sub-portion 5111 is spaced from the main body portion 121.

[0254] In some examples, one second protruding sub-portion 1222 can protrude from the side of one first protruding sub-portion 1221, or multiple second protruding sub-portion 1222 can protrude. The multiple second protruding sub-portion 1222 are spaced along the second direction.

[0255] By adopting the technical solution of this embodiment, the first connecting portion 31 is welded to the first protruding sub-portion 1221 to form the first welding mark sub-portion 5111. The dimension l3 of the first protruding sub-portion 1221 in the second direction is large, which is beneficial to increasing the welding area between the protruding portion 122 and the first connecting portion 31, increasing the current-carrying area between the protruding portion 122 and the first connecting portion 31, improving the current-carrying capacity, reducing the heat generation of the battery cell 100, and being beneficial to improving the fast charging performance and service reliability of the battery cell 100. In addition, in the second direction, the dimension of the second protruding sub-portion 1222 is small, which is beneficial to reducing the occupied space of the protruding portion 122 and is beneficial to increasing the energy density of the battery cell 100.

[0256] In some embodiments, in the second direction, the first welding mark sub-portion 5111 extends from one side edge of the first protruding sub-portion 1221 to the other side edge of the first protruding sub-portion 1221.

[0257] In the first direction, the projection of the first welding mark sub-portion 5111 falls within the projection of the first protruding sub-portion 1221.

[0258] By adopting the technical solution of this embodiment, the dimension of the first welding mark sub-portion 5111 in the second direction is large, which is beneficial to increasing the welding area between the protruding portion 122 and the first connecting portion 31, increasing the current-carrying area between the protruding portion 122 and the main body portion 121, improving the current-carrying capacity, reducing the heat generation of the battery cell 100, and being beneficial to improving the fast charging performance and service reliability of the battery cell 100.

[0259] In some embodiments, the first welding mark portion 511 further includes a second welding mark sub-portion 5112. The first connecting portion 31 is welded to the surface of the second protruding sub-portion 1222 facing away from the insulating base 11 to form the second welding mark sub-portion 5112.

[0260] Exemplarily, the surface of the second protruding sub-portion 1222 facing away from the insulating base 11 is welded to the first connecting portion 31, and the trace generated by the welding is the second welding mark sub-portion 5112.

[0261] By adopting the technical solution of this embodiment, the second protruding sub-portion 1222 is also welded to the first connecting portion 31, which is beneficial to increasing the current-carrying area between the first connecting portion 31 and the protruding portion 122 and is beneficial to improving the current-carrying capacity between the first connecting portion 31 and the protruding portion 122.

[0262] In some embodiments, in the second direction, the second welding mark sub-portion 5112 extends from one side edge of the second protruding sub-portion 1222 to the other side edge of the second protruding sub-portion 1222.

[0263] In the first direction, the projection of the second welding mark sub-portion 5112 falls within the projection of the second protruding sub-portion 1222.

[0264] By adopting the technical solution of this embodiment, the size of the second welding mark sub - part 5112 in the second direction is large, which is beneficial to increasing the welding area between the first connecting part 31 and the protruding part 122, increasing the current - passing area between the first connecting part 31 and the protruding part 122, and is beneficial to improving the current - passing capacity between the first connecting part 31 and the protruding part 122.

[0265] In some embodiments, the main body part 121 includes a transition part 1211 and a conductive part 1212. The transition part 1211 is connected between the protruding part 122 and the conductive part 1212. The conductive part 1212 is covered with an active material layer 20, and the transition part 1211 and the protruding part 122 are not covered with the active material layer 20. The first connecting part 31 is connected to the surface of the transition part 1211 facing away from the insulating substrate 11.

[0266] Exemplarily, along the first direction, the main body part 121 is divided into two parts. The part close to the protruding part 122 is the transition part 1211, and the part far from the protruding part 122 is the conductive part 1212. The protruding part 122 protrudes away from the conductive part 1212 from the edge of the transition part 1211 facing away from the conductive part 1212; the conductive part 1212 is covered with the active material layer 20, and neither the transition part 1211 nor the protruding part 122 is covered with the active material layer 20 to facilitate connection with the first connecting part 31. Along the second direction, the size L1 of the conductive part 1212 is equal to the size l2 of the main body part 121.

[0267] In some examples, the protruding part 122 extends outward along the first direction from the side of the transition part 1211 facing away from the conductive part 1212 and forms a stepped structure; along the second direction, the sum l1 of the sizes of all the first protruding sub - parts 1221 of the protruding part 122 is less than or equal to the size L2 of the transition part 1211.

[0268] In some examples, the first connecting part 31 is connected to the surface of the transition part 1211 facing away from the insulating substrate 11 by welding or conductive adhesive, etc., to realize the connection between the first connecting part 31 and the transition part 1211.

[0269] By adopting the technical solution of this embodiment, the surface of the transition part 1211 in the main body part 121 facing away from the insulating substrate 11 is connected to the first connecting part 31, so that a part of the current can directly flow into or out of the first connecting part 31 through the transition part 1211, reducing the current - passing pressure between the protruding part 122 and the main body part 121, being beneficial to reducing the heat generation at the first protruding sub - part 1221, and being beneficial to improving the fast - charging performance and service reliability of the battery cell 100.

[0270] In some embodiments, along the second direction, the size of the conductive part 1212 is L1, the size of the transition part 1211 is L2, and 0.8 ≤ L2 / L1 ≤ 1.

[0271] 0.8 ≤ L2 / L1 ≤ 1. Along the second direction, the dimension L2 of the transition portion 1211 is less than or equal to the dimension L1 of the conductive portion 1212, and the dimension L2 of the transition portion 1211 is more than 0.8 times the dimension L1 of the conductive portion 1212. The dimension L2 of the transition portion 1211 exceeds more than half of the dimension L1 of the conductive portion 1212. The larger the dimension L2 of the transition portion 1211, the larger the connection area between the transition portion 1211 and the first connection portion 31 can be set, and the better the current-carrying capacity between the transition portion 1211 and the first connection portion 31.

[0272] In some examples, 0.8 ≤ L2 / L1 < 1. Along the second direction, the transition portion 1211 can be located at the middle position of the conductive portion 1212, and the two ends of the transition portion 1211 are not flush with the conductive portion 1212.

[0273] In some examples, 0.8 ≤ L2 / L1 < 1. Along the second direction, the transition portion 1211 can also be disposed to be biased towards one end of the conductive portion 1212, such that one end of the transition portion 1211 is flush with the conductive portion 1212 and the other end is not flush, or neither end is flush. The value of L2 / L1 can be but is not limited to 0.8, 1, or any value between 0.8 and 1. By way of example, the value of L2 / L1 can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0274] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L2 / L1 ≤ 1 makes the dimension L2 of the transition portion 1211 close to the dimension L1 of the conductive portion 1212 along the second direction. The relatively large dimension of the transition portion 1211 is beneficial to increasing the connection area between the first connection portion 31 and the transition portion 1211, improving the current-carrying capacity at the connection between the first connection portion 31 and the transition portion 1211, improving the current-carrying capacity of the first electrode tab 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance of the battery cell 100.

[0275] In some embodiments, L2 = L1.

[0276] L2 / L1 = 1. Along the second direction, the dimension L2 of the transition portion 1211 is equal to the dimension L1 of the conductive portion 1212. In the second direction, the two ends of the transition portion 1211 are flush with the conductive portion 1212, and the main body portion 121 has an equal-length structure.

[0277] By adopting the technical solution of this embodiment, the design of L2 = L1 makes the dimension of the transition portion 1211 along the second direction relatively large, which is beneficial to designing a relatively large connection area between the first connection portion 31 and the transition portion 1211. The current-carrying capacity at the connection between the first connection portion 31 and the transition portion 1211 is the best, which can effectively improve the current-carrying capacity of the first electrode tab 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell 100.

[0278] Please also refer to FIGS. 11 to 17. In some embodiments, the first solder mark 51 further includes a second solder mark portion 512. The first connecting portion 31 is welded to the surface of the transition portion 1211 facing away from the insulating substrate 11 to form the second solder mark portion 512.

[0279] The first connecting portion 31 is welded to the surface of the transition portion 1211 facing away from the insulating substrate 11, and the mark generated by the welding of the transition portion 1211 and the first connecting portion 31 is the second solder mark portion 512.

[0280] In some examples, the first solder mark 51 includes a second solder mark portion 512 and a first solder mark portion 511. The first solder mark portion 511 is located between the second solder mark portion 512 and the active material layer 20, that is, the first connecting portion 31 is welded to both the transition portion 1211 and the protruding portion 122 simultaneously.

[0281] By adopting the technical solution of this embodiment, the first connecting portion 31 and the transition portion 1211 are connected by welding. The connection method is simple, which is beneficial to the fabrication of the first electrode plate 1. In addition, the second solder mark portion 512 can be directly used for current conduction between the first connecting portion 31 and the transition portion 1211, which is beneficial to improving the current conduction ability between the first connecting portion 31 and the transition portion 1211 and reducing the heat generation of the battery cell 100.

[0282] In some embodiments, the first solder mark 51 can be only the first solder mark portion 511, that is, the first connecting portion 31 is welded to the protruding portion 122 and not welded to the transition portion 1211.

[0283] In some embodiments, the first solder mark 51 can be only the second solder mark portion 512, that is, the first connecting portion 31 is welded to the transition portion 1211 and not welded to the protruding portion 122.

[0284] In some embodiments, along the second direction, the size of the transition portion 1211 is L2, and the size of the second solder mark portion 512 is L3, where 0.8 ≤ L3 / L2 ≤ 1.

[0285] When 0.8 ≤ L3 / L2 ≤ 1, along the second direction, the size L3 of the second solder mark portion 512 can be less than or equal to the size L2 of the transition portion 1211. The size L3 of the second solder mark portion 512 is more than 0.8 times the size L2 of the transition portion 1211, and the size L3 of the second solder mark portion 512 exceeds half of the size L2 of the transition portion 1211. The longer the size L3 of the second solder mark portion 512, the larger the welding area between the transition portion 1211 and the first connecting portion 31, and the better the current conduction ability at the connection between the transition portion 1211 and the first connecting portion 31.

[0286] In some examples, 0.8 ≤ L3 / L2 < 1. Along the second direction, the second welding mark portion 512 can be located at the middle position of the transition portion 1211, and both ends of the second welding mark portion 512 are not flush with the transition portion 1211.

[0287] In some examples, 0.8 ≤ L2 / L1 < 1. Along the second direction, the second welding mark portion 512 can also be disposed to be biased towards one end of the transition portion 1211, such that one end of the transition portion 1211 is flush with the transition portion 1211, the other end is not flush, or neither end is flush.

[0288] The value of L3 / L2 can be but is not limited to 0.8, 1, or any value between 0.8 and 1. By way of example, the value of L3 / L2 can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0289] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L3 / L2 ≤ 1 makes the size of the second welding mark portion 512 larger along the second direction, which is beneficial to increasing the connection area between the first connection portion 31 and the transition portion 1211, improving the current-carrying capacity at the connection between the first connection portion 31 and the transition portion 1211, improving the current-carrying capacity of the first pole piece 1, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell 100.

[0290] In some embodiments, L3 = L2.

[0291] L3 / L2 = 1. Along the second direction, the size L3 of the second welding mark portion 512 is equal to the size L2 of the transition portion 1211, and both ends of the second welding mark portion 512 are flush with the transition portion 1211.

[0292] In some examples, the protruding portion 122 and the transition portion 1211 are simultaneously welded to the first connection portion 31 to form the entire welding mark. Welding the first connection portion 31 to the transition portion 1211 can effectively increase the welding area between the first connection portion 31 and the metal layer 12, increase the current-carrying area between the first connection portion 31 and the metal layer 12, and is beneficial to improving the current-carrying capacity between the first connection portion 31 and the metal layer 12.

[0293] During the process of cutting the conductive member 30, first cut along the second direction on the equal-width solder mark, and then cut along the direction away from the active material layer 20 until leaving the equal-width solder mark. After that, continue to cut along the direction away from the active material layer 20 for a certain distance, then continue to cut along the second direction for a certain distance, and then cut along the direction towards the active material layer 20 until cutting a certain distance of the equal-width solder mark. Then, continue to cut along the second direction on the equal-width solder mark, and so on in a cycle, and the first solder mark 51 can be obtained. Among them, taking the cutting position along the second direction on the equal-width solder mark as a reference, along the first direction, the part of the first solder mark 51 located on the side of the cutting position towards the active material layer 20 is the second solder mark portion 512, and the part located on the side of the cutting position away from the active material layer 20 is the first solder mark portion 511. The first solder mark portion 511 can be a convex structure of the second solder mark portion 512 away from the active material layer 20. After cutting is completed, during the cutting process from the direction away from the active material layer 20 to the direction towards the active material layer 20, a convex portion 122 is cut out from the metal layer 12 of the current collector 10, and during the cutting process along the second direction, a part located between the convex portion 122 and the active material layer 20 forms a transition portion 1211.

[0294] By adopting the technical solution of this embodiment, the design of L3 / L2 = 1 makes the size of the second solder mark portion 512 along the second direction larger, which is beneficial to designing a larger welding area between the first connecting portion 31 and the transition portion 1211. The current-carrying capacity at the connection between the first connecting portion 31 and the transition portion 1211 is the best, which can effectively improve the current-carrying capacity of the first electrode plate 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell 100.

[0295] In some embodiments, along the second direction, the size L4 of the first solder mark portion 511 is smaller than the size L3 of the second solder mark portion 512.

[0296] By adopting the technical solution of this embodiment, along the second direction, the size L3 of the second solder mark portion 512 is large, and the welding area between the transition portion 1211 and the first connecting portion 31 is large, which is beneficial to improving the current-carrying capacity of the first connecting portion 31 and the transition portion 1211, and is beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0297] In some embodiments, the number of the convex portions 122 is multiple, and the multiple convex portions 122 are arranged at intervals along the second direction, and each convex portion 122 is welded to the first connecting portion 31.

[0298] The number of the convex portions 122 is multiple, for example: two, three, four, etc.; the multiple convex portions 122 are arranged at intervals along the second direction.

[0299] In some examples, after the first electrode tab 1 is wound or stacked, multiple protruding portions 122 are stacked together, and at the same time, multiple second connection portions 32 are also stacked together, thereby breaking the insulation limit of the insulating matrix 11, effectively improving the conductivity of the first electrode tab 1, improving the fast charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the reliability of use of the battery cell 100. Metal layer 12.

[0300] The multiple protruding portions 122 are arranged at intervals along the second direction, such that along the second direction, the sum of the sizes l1 of the first protruding sub-portions 1221 of all the protruding portions 122 is smaller than the size l2 of the main body portion 121, the sum of the sizes L4 of all the first welding imprint portions 511 is smaller than the size L3 of the second welding imprint portion 512, and the large size L3 of the second welding imprint portion 512 is beneficial to increasing the welding area between the transition portion 1211 and the first connection portion 31, beneficial to increasing the current-carrying capacity at the connection between the transition portion 1211 and the conductive member 30, beneficial to increasing the current-carrying capacity of the first electrode tab 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance and reliability of use of the battery cell 100.

[0301] Among the multiple first welding imprint portions 511, along the second direction, the sizes L4 of some of the first welding imprint portions 511 may be the same, or the sizes L4 of all the first welding imprint portions 511 may be completely different, or the sizes L4 of all the first welding imprint portions 511 may be the same.

[0302] By adopting the technical solution of this embodiment, the multiple protruding portions 122 are arranged at intervals along the second direction, which is beneficial to dividing the conductive portion 1212 into multiple regions along the second direction, and one region can correspond to one protruding portion 122. The electrons in each region can be transmitted to the electrode lead-out portion 2011 through the corresponding protruding portion 122, so that the electrons of the main body portion 121 are transmitted in sub-regions. The electron transmission path in each region to the corresponding protruding portion 122 is short, which is beneficial to reducing the electron transmission distance, reducing the overall resistance of the first electrode tab 1, and improving the fast charging performance and reliability of use of the battery cell 100.

[0303] In some embodiments, the first connection portion 31 includes multiple first connection sub-portions 311, the multiple first connection sub-portions 311 are arranged at intervals along the second direction, the number of the second connection portions 32 is multiple, and each first connection sub-portions 311 is connected to each second connection portion 32 in one-to-one correspondence; each first connection sub-portions 311 is welded to the surface of each protruding portion 122 facing away from the insulating matrix 11 in one-to-one correspondence.

[0304] The first connecting sub - part 311 may refer to the part of the first connecting part 31 covering the protruding part 122; the number of the first connecting sub - parts 311, the number of the second connecting parts 32, and the number of the protruding parts 122 are the same. One first connecting sub - part 311 corresponds to one protruding part 122, one first connecting sub - part 311 is correspondingly connected to one second connecting part 32, and one first connecting sub - part 311 and one protruding part 122 are welded to form a first welding mark part 511.

[0305] By adopting the technical solution of this embodiment, multiple first connecting sub - parts 311 of the first connecting part 31 are arranged at intervals along the second direction, and there is a gap between two adjacent first connecting sub - parts 311, which can reduce the material required for the first connecting part 31 and lower the manufacturing cost of the battery cell 100.

[0306] In some embodiments, the number of the protruding parts 122 is multiple, and the multiple protruding parts 122 are arranged at intervals along the second direction; the first connecting part 31 includes a second connecting sub - part 312 and multiple first connecting sub - parts 311, the multiple first connecting sub - parts 311 are arranged at intervals along the second direction, and each first connecting sub - part 311 is welded to the surface of each protruding part 122 facing away from the insulating substrate 11; the number of the second connecting parts 32 is multiple, and along the first direction, one side of each first connecting sub - part 311 is correspondingly connected to each second connecting part 32, and the other side of each first connecting sub - part 311 is connected to the second connecting sub - part 312, and the second connecting sub - part 312 is continuously arranged along the second direction; the second connecting sub - part 312 is welded to the surface of the transition part 1211 facing away from the insulating substrate 11.

[0307] The second connecting sub - part 312 may refer to the part of the first connecting part 31 covering the transition part 1211; the second connecting sub - part 312 is continuously arranged along the second direction. For example, along the second direction, the second connecting sub - part 312 extends from one side edge of the transition part 1211 to the other side of the transition part 1211.

[0308] The second connecting sub - part 312 is welded to the surface of the transition part 1211 facing away from the insulating substrate 11 to form a second welding mark part 512.

[0309] By adopting the technical solution of this embodiment, the second connecting sub - part 312 is continuously arranged along the second direction, and multiple first connecting sub - parts 311 can be connected into a whole. The second connecting sub - part 312 can play a good supporting role for the first connecting sub - part 311, reduce the risk of the first connecting sub - part 311 being bent when inserted between the first pole piece 1 and the second pole piece 2, reduce the short - circuit risk, and is beneficial to improving the use reliability of the battery cell 100. In addition, along the second direction, the size of the second connecting sub - part 312 is large, which is beneficial to increasing the welding area between the second connecting sub - part 312 and the transition part 1211, beneficial to improving the current - carrying capacity at the connection between the first connecting part 31 and the transition part 1211, improving the current - carrying capacity of the first pole piece 1, and improving the fast - charging performance and use reliability of the battery cell 100.

[0310] In some embodiments, along the second direction, the sum of the sizes L4 of all the first welding imprints 511 is less than the size L3 of the second welding imprint 512.

[0311] By adopting the technical solution of this embodiment, along the second direction, the sum of the sizes L4 of all the first welding imprints 511 is less than the size L3 of the second welding imprint 512. The large size L3 of the second welding imprint 512 is beneficial to increasing the welding area between the transition part 1211 and the first connecting part 31, beneficial to improving the current - carrying capacity at the connection between the transition part 1211 and the conductive member 30, beneficial to improving the current - carrying capacity of the first pole piece 1, reducing the heat generation of the battery cell 100, and improving the fast - charging performance and use reliability of the battery cell 100.

[0312] In some examples, the second welding imprint 512 and the first welding imprint 511 are directly connected.

[0313] The second welding imprint 512 and the first welding imprint 511 form a whole first welding imprint 51, and there is no obvious boundary line between them; the whole first welding imprint 51 can cover the junction of the protruding part 122 and the transition part 1211; in the actual manufacturing process, the second welding imprint 512 and the first welding imprint 511 are formed by cutting the equal - width welding imprint as described above.

[0314] In some examples, the second welding imprint 512 and the first welding imprint 511 adopt the structure of welding points, and the pitch of the welding points in the second welding imprint 512 is the same as the pitch of the welding points in the first welding imprint 511; for example: the welding points in the second welding imprint 512 and the first welding imprint 511 are not welded to the junction line of the protruding part 122 and the transition part 1211, and the distance between adjacent welding points in the second welding imprint 512 and the first welding imprint 511 is equal to the pitch of the welding points in the second welding imprint 512; for example, the welding points are welded to the junction line of the protruding part 122 and the transition part 1211, thereby connecting the second welding imprint 512 and the first welding imprint 511 into a whole welding imprint.

[0315] By adopting the technical solution of this embodiment, the first welding mark 51 can cover the junction of the protruding portion 122 and the transition portion 1211. A part of the current can directly flow through the transition portion 1211 to the first connection portion 31, reducing the overcurrent pressure at the junction of the protruding portion 122 and the transition portion 1211, which is beneficial to improving the overcurrent capacity of the first electrode sheet 1, reducing the heat generation of the battery cell 100, and is beneficial to improving the fast charging performance of the battery cell 100.

[0316] In some embodiments, along the first direction, the first connection portion 31 is spaced apart from the active material layer 20.

[0317] The first connection portion 31 is not in direct contact with the active material layer 20, but there is a certain gap therebetween, such that the first connection portion 31 does not contact the active material layer 20.

[0318] In some examples, the first electrode sheet 1 is a positive electrode sheet. The non-contact between the first connection portion 31 and the active material layer 20 can reduce risks such as lithium deposition, which is beneficial to improving the use reliability of the battery cell 100. In other examples, the first electrode sheet 1 is a negative electrode sheet, and the first connection portion 31 may or may not be in contact with the active material layer 20.

[0319] By adopting the technical solution of this embodiment, the first connection portion 31 is not in contact with the active species layer, which can reduce the mutual influence therebetween and improve the use reliability of the battery cell 100.

[0320] In some embodiments, the electrode assembly 101 further includes an insulating member 40. The insulating member 40 includes a first insulating portion 41. The first insulating portion 41 covers the surface of the metal layer 12 facing away from the insulating substrate 11, and the entire first insulating portion 41 is located between the first welding mark 51 and the active material layer 20.

[0321] The insulating member 40 may refer to a component capable of insulating. The insulating member 40 includes a first insulating portion 41. The first insulating portion 41 may refer to an insulating component covering the surface of the metal layer 12 facing away from the active material layer 20; the first insulating portion 41 may be, but is not limited to, an insulating coating, an insulating adhesive (such as: hot melt adhesive) or an insulating tape.

[0322] Along the thickness direction of the current collector 10, the first insulating portion 41 does not coincide with the first welding mark 51, and the first insulating portion 41 is spaced apart from the first welding mark 51, such that the first connection portion 31 will not be welded to the first insulating portion 41, which is beneficial to reducing the risk of virtual soldering between the first connection portion 31 and the metal layer 12; or, the first insulating portion 41 coincides with the first welding mark 51 only at the edge, and the edge of the first welding mark 51 coincides with the edge of the first insulating portion 41, which can also reduce the risk of virtual soldering between the first connection portion 31 and the metal layer 12.

[0323] By adopting the technical solution of this embodiment, it is beneficial to reduce the risk of false soldering between the first connecting portion 31 and the metal layer 12, improve the connection reliability between the first connecting portion 31 and the metal layer 12, and also improve the current-carrying capacity.

[0324] In some embodiments, the first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0325] In some examples, the entire first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0326] In some examples, when the first connecting portion 31 is only soldered to the protruding portion 122 and the first connecting portion 31 is spaced from the transition portion 1211, a part of the first insulating portion 41 covers the protruding portion 122, and the other part covers the transition portion 1211. Such a setting can fully cover the part of the metal layer 12 located between the first connecting portion 31 and the active material layer 20. At the same time, it can also support the root of the protruding portion 122, reduce cracks, fractures and other damages that occur at the root of the protruding portion 122 during the manufacturing process of the battery device 1100, and is beneficial to improving the electron transport ability of the root of the protruding portion 122, and improving the fast charging performance and use reliability of the battery cell 100;

[0327] Of course, in other examples, the first insulating portion 41 may only cover the transition portion 1211.

[0328] In some examples, when both the protruding portion 122 and the transition portion 1211 are soldered to the first connecting portion 31, the first insulating portion 41 covers the transition portion 1211.

[0329] By adopting the technical solution of this embodiment, the first insulating portion 41 can support the part of the metal layer 12 located between the first connecting portion 31 and the active material layer 20, reduce cracks, fractures and other damages that occur in this part during the manufacturing process of the battery device 1100, and is beneficial to improving the electron transport ability of this part and the fast charging performance and use reliability of the battery cell 100; In addition, the first insulating portion 41 can also insulate this part, reduce the short-circuit risk of the battery cell 100, and improve the use reliability of the battery cell 100.

[0330] In some embodiments, the insulating member 40 further includes a second insulating portion 42, and at least a part of the second insulating portion 42 covers the first solder mark 51.

[0331] The second insulating portion 42 covers the surface of the first connecting portion 31 facing away from the metal layer 12 and covers at least a part of the first solder bump 51. Among them, the second insulating portion 42 may cover a part of the first solder bump 51 or the entire first solder bump 51. The second insulating portion 42 may be, but is not limited to, an insulating coating, an insulating adhesive (e.g., hot melt adhesive), or an insulating tape. The first insulating portion 41 and the second insulating portion 42 may be an integrally formed structure or two separate components connected together.

[0332] A part of the second insulating portion 42 may cover the first solder bump 51, and another part may cover the first insulating portion 41 or the active material layer 20. Or, the entire second insulating portion 42 covers the first solder bump 51.

[0333] In some examples, the first solder bump 51 includes a first solder bump portion 511, and the second insulating portion 42 covers at least a part of the first solder bump portion 511. The second insulating portion 42 may cover a part of the first solder bump portion 511 or the entire first solder bump portion 511.

[0334] In some examples, the first solder bump 51 includes a second solder bump portion 512 and a first solder bump portion 511, and the second insulating portion 42 covers the second solder bump portion 512 and the first solder bump portion 511.

[0335] After the first connecting portion 31 is welded to the metal layer 12, components such as tip protrusions and metal debris are likely to be generated on the surface of the first solder bump 51. However, in the embodiment of the present application, the second insulating portion 42 covers the surface of the first solder bump 51, which can prevent components such as tip protrusions and metal debris on the surface of the first solder bump 51 from piercing through the separator 3 and connecting to the second pole piece 2, reducing the short - circuit risk of the battery cell 100 and improving the reliability of use of the battery cell 100.

[0336] In some embodiments, along the first direction, one side of the second insulating portion 42 covers the first solder bump 51, and the other side of the second insulating portion 42 covers at least a partial area of the first insulating portion 41.

[0337] It can be understood that among the opposite two sides of the second insulating portion 42 along the first direction, one side covers the first solder bump 51, and the other side may cover the entire first insulating portion 41, or may cover a part of the first insulating portion 41, and even cover the active material layer 20.

[0338] Along the first direction, the second insulating portion 42 extends from the first solder bump 51 to the first insulating portion 41; or, the second insulating portion 42 extends from the first solder bump 51 to the active material layer 20, thereby completely covering the first insulating portion 41.

[0339] By adopting the technical solution of this embodiment, the second insulating part 42 and the first insulating part 41 jointly cover the extending part, enabling double-layer insulation, which is beneficial to reducing the short-circuit risk of the battery cell 100 and improving the usage reliability of the battery cell 100.

[0340] In some embodiments, the electrode assembly 101 further includes an insulating member 40. The insulating member 40 includes a second insulating part 42, and at least a part of the second insulating part 42 covers the first welding mark 51.

[0341] It can be understood that the insulating member 40 includes a second insulating part 42. The insulating member 40 may not include the first insulating part 41, or the insulating member 40 may include both the first insulating part 41 and the second insulating part 42.

[0342] By adopting the technical solution of this embodiment, the second insulating part 42 covers the surface of the first welding mark 51, which can prevent components such as tip protrusions and metal debris on the surface of the first welding mark 51 from piercing through the separator 3 and connecting to the second electrode plate 2, reducing the short-circuit risk of the battery cell 100 and improving the usage reliability of the battery cell 100.

[0343] Please refer to Figures 18 - 21 As shown, in some embodiments, along the first direction, one side of the second insulating part 42 covers the first welding mark 51, and the other side of the second insulating part 42 covers at least a part of the active material layer 20.

[0344] It can be understood that among the two sides of the second insulating part 42 distributed relatively along the first direction, one side covers the first welding mark 51, and the other side covers at least a part of the active material layer 20. Among them, the second insulating part 42 may cover the end of the active material layer 20 facing the first connection part 31, or may cover the entire active material layer 20.

[0345] Along the first direction, the second insulating part 42 extends from the first welding mark 51 to the active material layer 20, so that the part of the metal layer 12 and the first connection part 31 located between the first welding mark 51 and the active material layer 20 is covered. Among them, a first insulating part 41 may or may not be provided between the second insulating part 42 and the metal layer 12.

[0346] In some examples, the metal layer 12 is covered with a first insulating part 41. After the second insulating part 42 completely covers the first insulating part 41, it can further extend to the active material layer 20 to cover the active material layer 20. The metal layer 12 is covered with the first insulating part 41 and the second insulating part 42, achieving double-layer insulation with good insulation effect.

[0347] In some examples, the metal layer 12 is not covered by the first insulating portion 41, and the second insulating portion 42 extends from the first welding mark 51 to the active material layer 20, so as to cover the portion of the metal layer 12 between the first connecting portion 31 and the active material layer 20, reducing the risk of short circuit in this portion, which is beneficial to improving the reliability of use of the battery cell 100. In addition, the first insulating portion 41 can be omitted, saving costs. At the same time, the active material layer 20 can be used to cover the original position of the first insulating portion 41, which can increase the covering area of the active material layer 20 on the metal layer 12, and is beneficial to improving the energy density of the battery cell 100.

[0348] By adopting the technical solution of this embodiment, the second insulating portion 42 extends onto the active material layer 20 from the first welding mark 51. The second insulating portion 42 has a wide covering area and good insulating effect, which is beneficial to improving the reliability of use of the battery cell 100.

[0349] In some embodiments, along the first direction, the dimension of the portion of the insulating member 40 covering the active material layer 20 is H, where 0.2 mm ≤ H ≤ 1.0 mm. Optionally, 0.3 mm ≤ H ≤ 0.8 mm.

[0350] In some examples, the value of H can be 0.2 mm, 1 mm or any value between 0.2 mm and 1.0 mm. Exemplarily, the value of H can be, but is not limited to, 0.2 mm, 0.3 mm, 0.4 mm, 0.6 mm, 0.8 mm, 0.9 mm, 1 mm.

[0351] The design with H ≥ 0.2 mm enables the insulating member 40 to cover the end portion of the active material layer 20 facing the protruding portion 122. The insulating member 40 can block the burrs at the end portion of the active material layer 20 facing the protruding portion 122, improving the reliability of use of the battery cell 100; the design with H ≤ 1.0 mm enables the portion of the insulating member 40 covering the active material layer 20 not to be too large, which is beneficial to reducing the weight and volume of the insulating member 40 and is beneficial to improving the energy density of the battery cell 100.

[0352] In some examples, the insulating member 40 includes a first insulating portion 41. The first insulating portion 41 covers the end portion of the active material layer 20 facing the protruding portion 122. The portion of the first insulating portion 41 covering the active material layer 20 can refer to the mutually soluble region formed by the first insulating portion 41 and the active material layer 20, so that the fixation of the first insulating portion 41 is more stable.

[0353] In some examples, the insulating member 40 includes a second insulating portion 42. The second insulating portion 42 covers the end portion of the active material layer 20 facing the protruding portion 122.

[0354] By adopting the technical solution of this embodiment, along the first direction, the size of the part of the second insulating portion 42 covering the active material layer 20 is reasonable, and it can take into account both the burr at the end of the main body portion 121 facing the protruding portion 122 and the energy density of the battery cell 100.

[0355] In some embodiments, 0.3 mm ≤ H ≤ 0.8 mm.

[0356] By adopting the technical solution of this embodiment, along the first direction, the size of the part of the second insulating portion 42 covering the active material layer 20 is more reasonable, and it can better take into account the burr at the end of the main body portion 121 facing the protruding portion 122 and the energy density problem of the battery cell 100.

[0357] In some embodiments, along the direction from the main body portion 121 to the protruding portion 122, the second insulating portion 42 protrudes from the end face of the first protruding sub - portion 1221 facing away from the main body portion 121.

[0358] Along the thickness direction of the current collector 10, the projection of the end face of the first protruding sub - portion 1221 facing away from the main body portion 121 falls within the projection of the second insulating portion 42.

[0359] During the manufacturing process of the electrode, the end face of the first protruding sub - portion 1221 facing away from the main body portion 121 is obtained by cutting, resulting in burrs being easily generated on the end face of the first protruding sub - portion 1221 facing away from the main body portion 121. The second insulating portion 42 can block the burrs at the end face of the first protruding sub - portion 1221 facing away from the main body portion 121, reducing the short - circuit risk inside the battery cell 100 and being beneficial to improving the use reliability of the battery cell 100. In addition, the second insulating portion 42 can completely cover the first welding mark sub - portion 5111, reducing the risk of short - circuit caused by burrs, metal debris and other components on the first welding mark sub - portion 5111, and being beneficial to improving the use reliability of the battery cell 100.

[0360] In some embodiments, along the direction from the main body portion 121 to the protruding portion 122, the second insulating portion 42 protrudes from the edge of the second welding mark sub - portion 5112 facing away from the first protruding sub - portion 1221.

[0361] Along the thickness direction of the current collector 10, the projection of the edge of the second welding mark sub - portion 5112 facing away from the first protruding sub - portion 1221 falls within the projection of the second insulating portion 42, so that the second insulating portion 42 can completely cover the second welding mark sub - portion 5112 and the first welding mark sub - portion 5111.

[0362] During the production process of the electrode tab, the second insulating portion 42 can completely cover the second welding imprint sub-portion 5112 and the first welding imprint sub-portion 5111, reducing the risk of short circuit caused by burrs, metal debris and other components on the second welding imprint sub-portion 5112 and the first welding imprint sub-portion 5111, which is beneficial to improving the use reliability of the battery cell 100.

[0363] In some embodiments, the number of the metal layers 12 is two, and the two metal layers 12 are disposed on opposite sides of the insulating substrate 11 along the thickness direction of the current collector 10. The number of the active material layers 20 is two, and the two active material layers 20 respectively cover the two metal layers 12. The number of the conductive members 30 is two, and the first connection portions 31 of the two conductive members 30 are respectively welded to the surfaces of the two metal layers 12 facing away from the insulating substrate 11 to form two first welding imprints 51. The number of the insulating members 40 is two, and the second insulating portions 42 of the two insulating members 40 respectively cover at least a part of the two first welding imprints 51.

[0364] The number of the metal layers 12, the number of the insulating members 40, the number of the active material layers 20 and the number of the conductive members 30 are all two. The two metal layers 12 respectively cover opposite sides of the insulating substrate 11 along the thickness direction. The two active material layers 20 respectively cover the conductive portions 1212 of the two metal layers 12. The first connection portion 31 of one conductive member 30 is welded to the surface of one metal layer 12 facing away from the insulating substrate 11 to form a first welding imprint 51, and the first connection portion 31 of the other conductive member 30 is welded to the other metal layer 12 to also form a first welding imprint 51. The second insulating portions 42 of the two insulating members 40 are located on opposite sides of the insulating substrate 11 along the thickness direction and respectively cover the two first welding imprints 51.

[0365] By adopting the technical solution of this embodiment, the first connection portions 31 of the two conductive members 30 are respectively welded to the metal layers 12 located on opposite sides of the insulating substrate 11, and the second connection portions 32 of the two conductive members 30 are located on the side of the protruding portion 122 facing away from the main body portion 121. In this way, the two metal layers 12 can be directly connected by using the second connection portions 32 of the two conductive members 30, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductive ability of the first electrode tab 1, improving the fast charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the use reliability of the battery cell 100 and the metal layer 12.

[0366] In some embodiments, the second insulating portion 42 includes a first portion 421 and a second portion 422 connected to each other. The first portion 421 covers at least a part of the main body portion 121. Along the direction of the main body portion 121 towards the protruding portion 122, the second portion 422 protrudes from the main body portion 121, and the second portion 422 is located on the side of the protruding portion 122 along the second direction.

[0367] In some examples, the insulating member 40 has a constant width structure. The insulating member 40 covers the conductive member 30 and the metal layer 12 along the length direction of the first pole piece 1. Along the thickness direction of the current collector 10, the part of the second insulating portion 42 within the projection range of the metal layer 12 and the conductive member 30 is the first part 421, and the part of the second insulating portion 42 outside the projection range of the metal layer 12 and the conductive member 30 is the second part 422.

[0368] In some examples, during the process of cutting the conductive member 30, burrs are likely to be formed at the end face of the transition portion 1211 facing the protruding portion 122. In particular, during the process of cutting the conductive member 30 at the first welding mark 51, larger burrs are likely to be formed at the end face of the transition portion 1211 facing the protruding portion 122. The second insulating portion 42 of the embodiment of the present application can block the burrs at the end face of the transition portion 1211 facing the protruding portion 122 from piercing through the separator 3 and contacting the second pole piece 2, thereby reducing the short - circuit risk of the battery cell 100 and being beneficial to improving the use reliability of the battery cell 100.

[0369] In some examples, the end of the main body portion 121 facing the protruding portion 122 is easily impacted to generate metal debris, and the metal debris is likely to fall into the electrode assembly 101, resulting in a short - circuit of the battery cell 100. For example, the end of the transition portion 1211 facing the protruding portion 122 is easily impacted to generate metal debris, and the metal debris is likely to fall into the electrode assembly 101, resulting in a short - circuit of the battery cell 100.

[0370] By adopting the technical solution of this embodiment, along the direction from the main body portion 121 to the protruding portion 122, components such as metal debris at the end face of the main body portion 121 facing the protruding portion 122 can be located between the second parts 422 of the two insulating members 40. In this way, the risk of metal debris falling into the electrode assembly 101 can be reduced, which is beneficial to reducing the short - circuit risk.

[0371] In some embodiments, the second parts 422 of the two insulating members 40 are in contact with each other.

[0372] In some examples, the second parts 422 of the two insulating members 40 are located in the hollow area where the transition portion 1211 does not extend beyond the protruding portion 122, so that the second parts 422 of the two insulating members 40 can be close to each other and then fit together.

[0373] The second parts 422 of the two insulating members 40 can be pasted together, or can be statically adsorbed together. Of course, there can also be other fitting methods.

[0374] By adopting the technical solution of this embodiment, after the second parts 422 of the two insulating members 40 are fitted together, components such as metal debris at the end face of the main body portion 121 facing the protruding portion 122 can be covered, so that components such as metal debris are not easily dropped into the electrode assembly 101, and the short - circuit risk of the battery cell 100 can be better reduced.

[0375] In some embodiments, along the direction of the main body portion 121 facing the protruding portion 122, the second connecting portions 32 of the two conductive members 30 are welded to form a second weld mark 52.

[0376] In some examples, along the direction of the main body portion 121 pointing to the protruding portion 122, the portion of the conductive member 30 protruding from the protruding portion 122 forms the second connecting portion 32, so that the second connecting portions 32 of the two conductive members 30 can be directly opposite and close to each other for welding, and the trace left by welding is the second weld mark 52. The second connecting portions 32 of the two conductive members 30 can be welded by ultrasonic welding, laser welding and other methods.

[0377] By adopting the technical solution of this embodiment, the second connecting portions 32 of the two conductive members 30 can connect the metal layers 12 on the opposite sides of the insulating substrate 11, thus breaking the insulation limit of the insulating substrate 11, effectively improving the conductivity of the first pole piece 1, improving the fast - charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the use reliability of the battery cell 100.

[0378] In some embodiments, the second insulating portion 42 covers the second weld mark 52, and along the direction of the main body portion 121 pointing to the protruding portion 122, the second insulating portion 42 protrudes from the edge of the second weld mark 52 facing away from the main body portion 121.

[0379] Along the thickness direction of the current collector 10, the projection of the second weld mark 52 falls within the projection of the second insulating portion 42, so that the second insulating portion 42 can completely cover the second weld mark 52.

[0380] By adopting the technical solution of this embodiment, the second insulating portion 42 can completely cover the second weld mark 52, block components such as burrs and metal debris on the second weld mark 52 from piercing through the separator 3 and connecting with the second pole piece 2, reduce the short - circuit risk, and improve the use reliability of the battery cell 100.

[0381] In some embodiments, the electrode assembly 101 includes a second pole piece 2 with a polarity opposite to that of the first pole piece 1. The second pole piece 2 includes a main body functional portion 210 and a pole ear portion 220. The pole ear portion 220 protrudes from the main body functional portion 210 along the first direction; along the direction of the main body portion 121 pointing to the protruding portion 122, the main body functional portion 210 protrudes from the end face of the insulating member 40 close to the active material layer 20, and the main body functional portion 210 does not protrude from the end face of the insulating member 40 away from the active material layer 20.

[0382] The second electrode tab 2 may refer to an electrode tab with a polarity opposite to that of the first electrode tab 1. Among them, the first electrode tab 1 is a positive electrode tab and the second electrode tab 2 is a negative electrode tab, or the first electrode tab 1 is a negative electrode tab and the second electrode tab 2 is a positive electrode tab. The first electrode tab 1 and the second electrode tab 2 can be wound after being stacked to form a wound electrode assembly 101; a plurality of first electrode tabs 1 and a plurality of second electrode tabs 2 are stacked to form a stacked electrode assembly 101.

[0383] The second electrode tab 2 includes a main functional part 210 and an electrode ear part 220. The main functional part 210 may refer to the main body part of the second electrode tab 2, and the electrode ear part 220 may refer to the part of the second electrode tab 2 that protrudes from the main functional part 210; when the second electrode tab 2 is a negative electrode tab, the electrode ear part 220 may refer to the protruding structure located at the edge of the negative current collector mentioned above, and the main functional part 210 may include the part of the negative current collector other than the protruding structure and the negative active material layer. When the second electrode tab 2 is a positive electrode tab, the electrode ear part 220 may refer to the protruding structure located at the edge of the positive current collector mentioned above, and the main functional part 210 may include the part of the positive current collector other than the protruding structure and the positive active material layer.

[0384] During the manufacturing process of the second electrode tab 2, the edge of the second electrode tab 2 is die-cut to obtain the electrode ear part 220 and the main functional part 210. During the die-cutting process, burrs are likely to be generated on the end face of the main functional part 210 facing the electrode ear part 220.

[0385] Exemplarily, along the thickness direction of the current collector 10, the projection of the end face of the main functional part 210 close to the electrode ear part 220 falls within the projection of the first insulating part 41 or the projection of the second insulating part 42.

[0386] By adopting the technical solution of this embodiment, the insulating part 40 can prevent the burrs at the end face of the main functional part 210 of the second electrode tab 2 close to the electrode ear part 220 from piercing through the separator 3 and connecting to the first electrode tab 1, reducing the short-circuit risk between the first electrode tab 1 and the second electrode tab 2, and being beneficial to improving the use reliability of the battery cell 100.

[0387] In some embodiments, the electrode assembly 101 includes a second electrode tab 2 with a polarity opposite to that of the first electrode tab 1. The second electrode tab 2 includes a main functional part 210 and an electrode ear part 220. The electrode ear part 220 protrudes from the main functional part 210 along a first direction; along the direction from the main body part 121 to the protruding part 122, the main functional part 210 protrudes from the end of the main body part 121 facing the protruding part 122.

[0388] In the thickness direction of the current collector 10, the projection of the end face of the main functional part 210 facing the tab part 220 does not coincide with the projection of the main body part 121, so that the burrs at the end face of the main functional part 210 of the second electrode plate 2 facing the tab part 220 correspond to the hollow area of the main body part 121 where the convex part 122 is not extended.

[0389] In some examples, in the thickness direction of the current collector 10, the projection of the second welding mark part 512 may fall within the projection of the main functional part 210, and the second welding mark part 512 may be covered with the second insulating part 42, so that the second insulating part 42 can prevent burrs, metal debris and other components on the first welding mark 51 from piercing the separator 3 and connecting with the second electrode plate 2, reducing the risk of short circuit and improving the use reliability of the battery cell 100.

[0390] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional part 210 of the second electrode plate 2 facing the tab part 220 correspond to the hollow area of the main body part 121 where the convex part 122 is not extended, which can also reduce the short circuit risk of the battery cell 100 and improve the use reliability of the battery cell 100.

[0391] In some embodiments, along the first direction, the first welding mark 51 is arranged at an interval from the active material layer 20.

[0392] The first connecting part 31 will not be welded to the active material layer 20, which can reduce the risk of problems such as poor welding between the first connecting part 31 and the metal layer 12, is beneficial to improving the welding reliability between the first connecting part 31 and the metal layer 12, and is beneficial to improving the current-carrying capacity of the first electrode plate 1.

[0393] In some embodiments, along the first direction, the distance between the first welding mark 51 and the active material layer 20 is S1, where 0.3 mm ≤ S1 ≤ 5 mm.

[0394] In some examples, when the first welding mark 51 includes the first welding mark part 511 and does not include the second welding mark part 512, S1 is the distance from the first welding mark part 511 to the active material layer 20.

[0395] In some examples, when the first welding mark 51 includes the first welding mark part 511 and the second welding mark part 512, S1 is the distance from the second welding mark part 512 to the active material layer 20.

[0396] The design of S1 ≥ 0.3 mm makes there be a distance between the first welding mark 51 and the active material layer 20, so that the conductive component 30 will not be welded to the active material layer 20, reducing the risk of problems such as poor welding; the design of S1 ≤ 5 mm makes the distance between the first welding mark 51 and the active material layer 20 not too large, which is beneficial to increasing the covering area of the active material layer 20 on the metal layer 12 and is beneficial to improving the energy density of the battery cell 100.

[0397] The value of S1 can be 0.3 mm, 5 mm, or any value between 0.3 mm and 5 mm. By way of example, the value of S1 can be, but is not limited to, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 2.5 mm, 2.8 mm, 3 mm, 4 mm, 5 mm.

[0398] By adopting the technical solution of this embodiment, the design of 0.3 mm ≤ S1 ≤ 5 mm ensures that the first solder mark 51 will not be welded to the active material layer 20, reducing problems such as false soldering and facilitating the improvement of the connection reliability between the first connection portion 31 and the metal layer 12. Additionally, since the distance between the active material layer 20 and the first solder mark 51 is small, the active material layer 20 can be relatively close to the first solder mark 51. Then, when the size of the metal layer 12 in the first direction is fixed, the area that the active material layer 20 can cover is larger, which is conducive to improving the energy density of the battery cell 100.

[0399] In some embodiments, 0.5 mm ≤ S1 ≤ 2.8 mm.

[0400] By adopting the technical solution of this embodiment, the design of 0.5 mm ≤ S1 ≤ 2.8 mm makes the distance between the active material layer 20 and the first solder mark 51 more reasonable, better balancing the connection reliability of the conductive member 30 and the energy density of the battery cell 100.

[0401] In some embodiments, along the first direction, the first solder mark 51 is spaced from the end face of the first connection portion 31 facing the active material layer 20.

[0402] In some examples, the first electrode tab 1 is a positive electrode tab, and there is a gap between the first solder mark 51 and the active material layer 20. This gap can provide a spacing space between the conductive member 30 and the active material layer 20 to reduce the risk of lithium deposition caused by the contact between the conductive member 30 and the active material layer 20. Additionally, it can also provide a spacing space between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20, preventing the first solder mark 51 from extending to the end face of the first connection portion 31 facing the active material layer 20 and reducing the risks of the end face of the first connection portion 31 facing the active material layer 20 being burned through or cracked. This is conducive to reducing the burrs generated during welding and improving the service reliability of the battery cell 100.

[0403] In some examples, the first pole piece 1 is a negative pole piece, and there is a gap between the first welding mark 51 and the active material layer 20, which can provide a spaced space for the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, so that the second welding mark portion 512 will not extend to the end face of the first connecting portion 31 facing the active material layer 20, reducing the risks such as the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, which is beneficial to reducing the burrs generated by welding and is beneficial to improving the service reliability of the battery cell 100; wherein, the conductive member 30 may or may not be in contact with the active material layer 20.

[0404] There is a gap between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, so that the first welding mark 51 will not extend to the end face of the first connecting portion 31 facing the active material layer 20, reducing the risks such as the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, which is beneficial to reducing the burrs generated by welding and is beneficial to improving the service reliability of the battery cell 100.

[0405] In some embodiments, along the first direction, the spacing range between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20 is 0.3 mm to 1.2 mm.

[0406] Along the first direction, the spacing between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20 is S2, where 0.3 mm ≤ S2 ≤ 1.2 mm.

[0407] The design of S2 ≥ 0.3 mm makes there be a spacing between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, so that the first welding mark 51 will not extend to the end face of the first connecting portion 31 facing the active material layer 20, reducing the risks such as the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked; the design of S2 ≤ 1.2 mm makes the spacing between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20 not too large, which is beneficial to increasing the coverage area of the active material layer 20 on the metal layer 12 and is beneficial to improving the energy density of the battery cell 100.

[0408] The value of S2 can be 0.3 mm, 1.2 mm, and any value between 0.3 mm and 1.2 mm. Exemplarily, the value of S2 can be but is not limited to 0.3 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm.

[0409] By adopting the technical solution of this embodiment, the service reliability and energy density of the battery cell 100 can be better balanced.

[0410] In some embodiments, the current collector 10 further includes a conductive protective layer 13, and at least a part of the conductive protective layer 13 is located between the active material layer 20 and the metal layer 12.

[0411] The conductive protective layer 13 may refer to a conductive structure disposed between the active material layer 20 and the metal layer 12. This conductive structure can conduct electricity, enabling the battery cell 100 to output or input electrical energy. The conductive protective layer 13 can be a structure with equal thickness or an unequal-thickness structure.

[0412] Exemplarily, a part of the conductive protective layer 13 is located between the active material layer 20 and the conductive part 1212, and another part covers the transition part 1211 and protrudes outside the active material layer 20.

[0413] Exemplarily, the entire conductive protective layer 13 is located between the active material layer 20 and the conductive part 1212.

[0414] In some examples, the conductive protective layer 13 may contain conductive carbon black and a binder. On the one hand, it plays a buffering and lubricating role between the active material and the metal layer, and can alleviate the damage of the particles in the active material layer 20 to the metal layer 12 during the rolling process of the first electrode sheet 1. On the other hand, the conductive carbon black can reduce the contact resistance between the particles and the metal layer 12, which is beneficial to improving the performance of the battery cell 100.

[0415] During the rolling process of the first electrode sheet 1, the thickness of the metal layer 12 is relatively thin, and the particles in the active material layer 20 will cause damage to the metal layer 12, resulting in problems such as cracks in the metal layer 12. However, the conductive protective layer 13 in the embodiments of the present application can separate the active material layer 20 and the metal layer 12 and at the same time play a protective role for the metal layer 12, reducing the risks such as cracks in the metal layer 12 caused by rolling the active material layer 20, which is beneficial to improving the current-carrying capacity of the metal layer 12.

[0416] In some embodiments, along the direction from the main body part 121 to the protruding part 122, the conductive protective layer 13 protrudes from the end face of the active material layer 20 facing the protruding part 122.

[0417] The conductive protective layer 13 protrudes from the active material layer 20. The conductive protective layer 13 can completely separate the metal layer 12 and the active material layer 20. In addition, it can provide an extension space during the rolling process of the active material layer 20, which is beneficial to the subsequent conductive protective layer 13 being able to completely separate the metal layer 12 and the active material layer 20.

[0418] By adopting the technical solution of this embodiment, the conductive protective layer 13 can completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 13 has better protection ability for the metal layer 12, and the first electrode sheet 1 has better current-carrying capacity, which is beneficial to improving the fast charging performance and service reliability of the battery cell 100.

[0419] In some embodiments, along the direction from the main body portion 121 towards the protruding portion 122, the protruding distance range of the conductive protective layer 13 from the end face of the active material layer 20 facing the protruding portion 122 is 0.3 mm to 0.8 mm.

[0420] The protruding distance of the conductive protective layer 13 from the end face of the active material layer 20 facing the protruding portion 122 is S3, where 0.3 mm ≤ S3 ≤ 0.8 mm. The value of S3 can be 0.3 mm, 0.8 mm, and any value between 0.3 mm and 0.8 mm. For example, the value of S3 can be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm.

[0421] The design of S3 ≥ 0.3 mm enables the conductive protective layer 13 to completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 13 has better protection ability for the metal layer 12, and the current-carrying capacity of the first electrode tab 1 is better, which is beneficial to improving the fast charging performance and service reliability of the battery cell 100. The design of S3 ≤ 0.8 mm ensures that the conductive protective layer 13 is not too large and does not occupy space, which is beneficial to saving the internal space of the battery cell 100 and improving the energy density of the battery cell 100.

[0422] By adopting the technical solution of this embodiment, the current-carrying capacity and energy density of the battery cell 100 can be better balanced.

[0423] In some embodiments, the current collector 10 further includes a conductive protective layer 13. At least part of the conductive protective layer 13 is located between the active material layer 20 and the metal layer 12. Along the first direction, the conductive protective layer 13 and the first welding mark 51 are arranged at intervals.

[0424] In some examples, the conductive protective layer 13 and the first connecting portion 31 are arranged at intervals, and the first insulating portion 41 covers the part of the conductive protective layer 13 located between the first connecting portion 31 and the active material layer 20.

[0425] By adopting the technical solution of this embodiment, the first connecting portion 31 will not be welded to the conductive protective layer 13, which can reduce risks such as false soldering and is beneficial to improving the welding reliability between the first connecting portion 31 and the metal layer 12.

[0426] In some embodiments, the second insulating portion 42 is connected to the first electrode tab 1.

[0427] The second insulating portion 42 can be connected to the metal layer 12, the conductive member 30, or the active material layer 20. Among them, the second insulating portion 42 can be connected to the first electrode tab 1 by bonding or pasting.

[0428] By adopting the technical solution of this embodiment, the second insulating part 42 is connected to the first pole piece 1, and the second insulating part 42 can be fixed, so as to stably block the burrs at the end of the main body part 121 facing the protruding part 122, which is beneficial to improving the use reliability of the battery cell 100.

[0429] Please refer to Figure 22 and Figure 23 As shown, in some embodiments, the second insulating part 42 includes an insulating base layer 423 and an adhesive layer 424, and the adhesive layer 424 is bonded between the insulating base layer 423 and the first pole piece 1.

[0430] The second insulating part 42 adopts the structural form of a tape; the insulating base layer 423 may refer to the main body part of the second insulating part 42, and the adhesive layer 424 may refer to the adhesive covering the surface of the insulating base layer 423. The material of the insulating base layer 423 includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene and their block copolymers. The material of the adhesive layer 424 includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene or butyl rubber.

[0431] By adopting the technical solution of this embodiment, the second insulating part 42 adopts the structural form of a tape, and the tape is easy to cover comprehensively, which is beneficial to reducing the risk of missed coverage and reducing the risk of internal short circuit of the battery cell 100; the insulating base layer 423 can improve the structural strength of the second insulating part 42 and reduce the deformation during the fitting process of the second insulating part 42, which is beneficial to improving the insulation effect; the adhesive layer 424 can stably fix the insulating base layer 423 on the first pole piece 1 and reduce the risk of the insulating tape falling off.

[0432] In some embodiments, the layer thickness range of the insulating base layer 423 is 6μm to 15μm.

[0433] The layer thickness of the insulating base layer 423 is T1, 6μm ≤ T1 ≤ 15μm. It can be understood that the value of T1 can be 6μm, 15μm and any value between 6μm and 15μm. Exemplarily, the value of T1 can be but not limited to 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm.

[0434] The design of T1 ≥ 6μm enables the insulating base layer 423 to have a certain thickness to block burrs and achieve insulation; the design of T1 ≤ 15μm enables the thickness of the insulating base layer 423 not to be too large, which is beneficial to reducing the volume occupied by the second insulating part 42 and improving the energy density of the battery cell 100.

[0435] By adopting the technical solution of this embodiment, the internal insulation and energy density of the battery cell 100 can be taken into account at the same time.

[0436] In some embodiments, the thickness of the adhesive layer 424 ranges from 0.5 μm to 3 μm.

[0437] The thickness of the adhesive layer 424 is T2, where 0.5 μm ≤ T2 ≤ 3 μm. It can be understood that the value of T2 can be 0.3 μm, 3 μm, or any value between 0.3 μm and 3 μm. By way of example, the value of T2 can be, but is not limited to, 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm.

[0438] The design with T2 ≥ 0.5 μm gives the adhesive layer 424 a certain thickness, enabling the second insulating portion 42 to be stably adhered to the first pole piece 1, and the insulating reliability of the second insulating portion 42 is good. The design with T2 ≤ 3 μm ensures that the thickness of the adhesive layer 424 is not too large, which is beneficial for reducing the volume occupied by the second insulating portion 42 and for increasing the energy density of the battery cell 100.

[0439] By adopting the technical solution of this embodiment, both the insulating reliability and the energy density of the battery cell 100 can be taken into account simultaneously.

[0440] In some embodiments, the thickness of the insulating base layer 423 ranges from 6 μm to 15 μm; the thickness of the adhesive layer 424 ranges from 0.5 μm to 3 μm.

[0441] By adopting the technical solution of this embodiment, both the insulating reliability and the energy density of the battery cell 100 can be taken into account simultaneously.

[0442] In some embodiments, along the first direction, the dimension of the insulating member 40 is W, where 3 mm ≤ W ≤ 9 mm.

[0443] In some examples, the insulating member 40 includes the second insulating portion 42, and W is equal to the dimension of the second insulating portion 42 along the first direction.

[0444] In some examples, the insulating member 40 includes the second insulating portion 42 and the first insulating portion 41, and W is equal to the overall dimension of the second insulating portion 42 and the insulating coating along the first direction.

[0445] 3 mm ≤ W ≤ 9 mm. It can be understood that the value of W can be 3 mm, 9 mm, or any value between 3 mm and 9 mm. By way of example, the value of W can be, but is not limited to, 3 mm, 4 mm, 4.5 mm, 5 mm, 6 mm, 6.5 mm, 7 mm, 8 mm, 9 mm.

[0446] The design with W≥3mm gives the insulating member 40 a certain dimension in the first direction, which is beneficial to achieving internal insulation of the battery cell 100; the design with W≤9mm ensures that the dimension of the insulating member 40 in the first direction is not too large, which is conducive to reducing the occupied volume of the insulating member 40 and improving the energy density of the battery cell 100.

[0447] By adopting the technical solution of this embodiment, both the insulation reliability and energy density of the battery cell 100 can be taken into account simultaneously.

[0448] In some embodiments, 4.5mm≤W≤6.5mm.

[0449] By adopting the technical solution of this embodiment, the dimension of the insulating member 40 in the first direction is relatively reasonable, and it can better balance the insulation reliability and energy density of the battery cell 100.

[0450] In some embodiments, the main body portion 121 includes a transition portion 1211 and a conductive portion 1212. The transition portion 1211 is connected between the protruding portion 122 and the conductive portion 1212. The conductive portion 1212 is covered with an active material layer 20, and the transition portion 1211 is not covered with the active material layer 20; the transition portion 1211 is connected to the conductive member 30; at least part of the thickness of the conductive portion 1212 is less than the thickness of the transition portion 1211.

[0451] Exemplarily, the transition portion 1211 is an equal-thickness structure or substantially an equal-thickness structure, and the conductive portion 1212 is also an equal-thickness structure or substantially an equal-thickness structure. The thickness t1 of the transition portion 1211 is greater than the thickness of the conductive portion 1212.

[0452] Exemplarily, the conductive portion 1212 can have unequal thickness. Along the direction from the main body portion 121 to the protruding portion 122, the thickness of the conductive portion 1212 is set to increase. Specifically, it can increase step by step or increase slowly. The thickness of the part of the conductive portion 1212 far from the transition portion 1211 is less than the thickness of the transition portion 1211.

[0453] By adopting the technical solution of this embodiment, the thickness t1 of the transition portion 1211 is relatively large, and the current-carrying capacity of the transition portion 1211 is good, which is beneficial to improving the current-carrying capacity of the first electrode sheet 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance and service reliability of the battery cell 100.

[0454] In some embodiments, the conductive part 1212 includes a first sub - part 12121 and a second sub - part 12122. The first sub - part 12121 is connected between the second sub - part 12122 and the transition part 1211. The first sub - part 12121 and the second sub - part 12122 are covered with an active material layer 20. The thickness of the first sub - part 12121 is greater than the thickness of the second sub - part 12122, and the thickness of the transition part 1211 is greater than or equal to the thickness of the first sub - part 12121.

[0455] The conductive part 1212 can be a structure with unequal thicknesses. Along the direction from the main body part 121 to the protruding part 122, the conductive part 1212 is divided into two parts. The part close to the transition part 1211 is the first sub - part 12121, and the part far from the transition part 1211 is the second sub - part 12122. Both the first sub - part 12121 and the second sub - part 12122 are covered with the active material layer 20.

[0456] In some examples, the first sub - part 12121 can be a structure with uniform thickness, and the second sub - part 12122 can be a structure with uniform thickness; the thickness t2 of the first sub - part 12121 is greater than the thickness t3 of the second sub - part 12122, and the thickness t1 of the transition part 1211 is greater than or equal to the thickness t2 of the first sub - part 12121, such that the first sub - part 12121 and the second sub - part 12122 form a stepped structure; the thickness t1 of the transition part 1211 can be equal to the thickness t2 of the first sub - part 12121, such that the transition part 1211 and the first sub - part 12121 form a structure with uniform thickness; or, the thickness t1 of the transition part 1211 can be greater than the thickness t3 of the second sub - part 12122, such that the first sub - part 12121 and the transition part 1211 form a stepped structure.

[0457] In some examples, the first sub - part 12121 can also be a multi - segment structure. Along the direction from the main body part 121 to the protruding part 122, the thickness of each segment increases in sequence; for example, the first sub - part 12121 includes a first segment and a second segment. The first segment is located between the second segment and the second sub - part 12122. Along the direction from the main body part 121 to the protruding part 122, the thickness of the first segment gradually increases. The second segment is generally a structure with uniform thickness, and the thickness of the second segment is equal to the thickness t1 of the transition part 1211; the thickness of the first segment gradually increases from the thickness t3 of the second sub - part 12122 to the thickness of the second segment. With such a setting, the first segment can be smoothly connected to the second segment and the second sub - part 12122, which is beneficial to reducing stress concentration and improving the structural strength. The thickness of the first segment can be equal to the thickness t1 of the transition part 1211, or the thickness t1 of the transition part 1211 can also be greater than the thickness of the first segment.

[0458] During the use of the battery cell 100, electrons and ions generated by the active material layer 20 gradually converge on the transition part 1211 through the conductive part 1212 along the direction from the main body part 121 to the protruding part 122. The number of electrons and ions flowing through the part of the conductive part 1212 close to the transition part 1211 is more than that flowing through the part of the conductive part 1212 far from the transition part 1211. Therefore, the current-carrying capacity of the part of the conductive part 1212 close to the transition part 1211 should be greater than that of the part of the conductive part 1212 far from the transition part 1211.

[0459] In the embodiment of the present application, the first sub-part 12121 is connected between the second sub-part 12122 and the transition part 1211, and the thickness t2 of the first sub-part 12121 is greater than the thickness t3 of the second sub-part 12122, so that the current-carrying capacity of the first sub-part 12121 close to the transition part 1211 is greater than that of the second sub-part 12122 far from the transition part 1211. This can reduce the limitation of the current, improve the current-carrying capacity of the first electrode plate 1, reduce the heat generation of the battery cell 100, and is beneficial to improving the use reliability of the battery cell 100.

[0460] In some embodiments, the current collector 10 further includes a conductive protective layer 13. The conductive protective layer 13 includes a first protective part 131 and a second protective part 132. The first protective part 131 is located between the first sub-part 12121 and the active material layer 20, and the second protective part 132 is located between the second sub-part 12122 and the active material layer 20; wherein, the thickness of the first protective part 131 is less than the thickness of the second protective part 132, and the thickness of the third protective part 133 is less than or equal to the thickness of the first protective part 131.

[0461] In some examples, along the first direction, the part of the conductive protective layer 13 located between the first sub-part 12121 and the active material layer 20 may be the first protective part 131, and the part of the conductive protective layer 13 located between the second sub-part 12122 and the active material layer 20 may be the second protective part 132. Wherein, the thickness t4 of the first protective part 131 is less than the thickness t5 of the second protective part 132, and the thickness t2 of the first sub-part 12121 is greater than the thickness t3 of the second sub-part 12122, which can reduce the thickness difference between the first protective part 131 and the second protective part 132 of the current collector 10.

[0462] Exemplarily, the first sub - part 12121 is divided into a third part and a fourth part. The third part is located between the above - mentioned first section and the active material layer 20, and the fourth part is located between the above - mentioned second section and the active material layer 20. The third part is located between the fourth part and the second protection part 132. Along the direction from the main body part 121 to the protruding part 122, the thickness of the third part gradually decreases, and the fourth part is generally of an equal - thickness structure, such that the thickness t4 of the first protection part 131 can be adapted to the thickness t2 of the first sub - part 12121, making the surface of the conductive protection layer 13 facing away from the insulating substrate 11 close to a plane.

[0463] By adopting the technical solution of this embodiment, the surface of the conductive protection layer 13 facing away from the insulating substrate 11 is close to a plane, which is beneficial to reducing rolling damage and improving the current - carrying capacity of the metal layer 12. Additionally, it can also reduce the problem of winding bulging of the current collector 10.

[0464] In some embodiments, the conductive protection layer 13 further includes a third protection part 133. The third protection part 133 covers the surface of the transition part 1211 facing away from the insulating substrate 11, and the thickness of the third protection part 133 is less than or equal to the thickness of the first protection part 131.

[0465] In some examples, along the first direction, the conductive protection layer 13 can be divided into three parts. A part close to the conductive member 30 is the third protection part 133, a part far from the conductive member 30 is the second protection part 132, and the part in the middle is the first protection part 131. Among them, the thickness t4 of the first protection part 131 is less than the thickness t5 of the second protection part 132, and the thickness t2 of the first sub - part 12121 is greater than the thickness t5 of the second protection part 132, which can reduce the thickness difference between the current collector 10 at the first protection part 131 and the second protection part 132. Similarly, the thickness t6 of the third protection part 133 is less than or equal to the thickness t4 of the first protection part 131, and the thickness t1 of the transition part 1211 is greater than or equal to the thickness t2 of the first sub - part 12121, which can reduce the thickness difference between the current collector 10 at the first protection part 131 and the third protection part 133, being beneficial to the surface of the conductive protection layer 13 facing away from the metal layer 12 approaching a plane.

[0466] Exemplarily, the second protection part 132, the third protection part 133, the transition part 1211, and the second sub - part 12122 are all of equal - thickness structures, while the first sub - part 12121 and the first protection part 131 are both of unequal - thickness structures. The thickness t2 of the first sub - part 12121 is adapted to the thickness t4 of the first protection part 131 so that the surface of the conductive protection layer 13 facing away from the insulating substrate 11 is close to a plane.

[0467] By adopting the technical aspects of this embodiment, the setting of the third protection part 133 enables the conductive protection layer 13 to protrude from the active material layer 20, so that the active material layer 20 and the metal layer 12 can be better separated. In addition, the thickness of the third protection part 133 is not too large, which is conducive to reducing material waste and saving the manufacturing cost of the battery cell 100.

[0468] In some embodiments, the thickness t7 of the protruding part 122 is greater than or equal to the thickness t1 of the transition part 1211.

[0469] Exemplarily, the thickness t7 of the protruding part 122 may be equal to the thickness t1 of the transition part 1211, so that the protruding part 122 and the transition part 1211 form an isometric structure.

[0470] Exemplarily, the thickness t7 of the protruding part 122 may also be greater than the thickness t1 of the transition part 1211, so that the protruding part 122 and the transition part 1211 form a stepped structure.

[0471] By adopting the technical solution of this embodiment, the relatively thick thickness t7 of the protruding part 122 can improve the current-carrying capacity of the protruding part 122, which is conducive to improving the current-carrying capacity of the first pole piece 1, reducing the heat generation of the battery cell 100, and is conducive to improving the fast charging performance and use reliability of the battery cell 100.

[0472] In some embodiments, the thickness of the second active material part 22 is t8, where 0.002 ≤ (t1 - t3) / t8 ≤ 0.08.

[0473] t1 - t3 may refer to the thickness difference between the transition part 1211 and the second sub-part 12122.

[0474] (t1 - t3) / t8 can be 0.002, 0.08, and any value between 0.002 and 0.08; Exemplarily, the value of (t1 - t3) / t8 can be but not limited to 0.002, 0.003, 0.004, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08.

[0475] By adopting the technical solution of this embodiment, the setting of 0.002 ≤ (t1 - t3) / t8 ≤ 0.08 enables the thickness difference between the transition part 1211 and the second sub-part 12122 to be within the thickness error range of the active material layer 20. In this way, thickening the transition part 1211 is not likely to cause the surface of the active material layer 20 to protrude, which can reduce subsequent rolling damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, and is conducive to improving the use reliability of the battery cell 100.

[0476] In some embodiments, 0.003 ≤ (t1 - t3) / t8 ≤ 0.06.

[0477] By adopting the technical solution of this embodiment, the setting of 0.003 ≤ (t1 - t3) / t8 ≤ 0.06 enables the thickness difference between the transition part 1211 and the second sub-part 12122 to be better within the thickness difference range of the active material layer 20. In this way, thickening the transition part 1211 is less likely to cause the surface of the active material layer 20 to bulge, which can reduce subsequent rolling damage and the extrusion damage between the first electrode sheet 1 and other electrode sheets, and is beneficial to improving the service reliability of the battery cell 100.

[0478] In some embodiments, 60μm ≤ t8 ≤ 250μm.

[0479] It can be understood that the value of t8 can be 60μm, 250μm, and any value between 60μm and 250μm; for example, the value of t8 can be, but is not limited to, 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, 250μm.

[0480] The design of t8 ≥ 60μm enables the battery cell 100 to have a higher capacity; the design of t3 ≤ 250μm makes the distance for electrons to escape in the part of the active material layer 20 close to the metal layer 12 not too long, and it is easy for electrons to escape in the part of the active material layer 20 close to the metal layer 12, which is beneficial to improving the capacity of the battery cell 100.

[0481] By adopting the technical solution of this embodiment, the thickness of the second active material part 22 is within a suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and service reliability of the battery cell 100, and can also reduce the risk of difficult ion escape in the area of the active material layer 20 close to the conductive layer, improving the performance of the battery cell 100.

[0482] In some embodiments, 80μm ≤ t8 ≤ 180μm.

[0483] By adopting the technical solution of this embodiment, the setting of 80μm ≤ t8 ≤ 180μm makes the thickness of the second active material part 22 within a more suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and service reliability of the battery cell 100, and can also reduce the risk of difficult ion escape in the area of the active material layer 20 close to the conductive layer, improving the performance of the battery cell 100.

[0484] In some embodiments, 0.2μm ≤ t1 - t3 ≤ 4.5μm.

[0485] t1 - t3 may refer to the thickness difference between the transition part 1211 and the second sub - part 12122, so as to characterize the thickening degree of the transition part 1211.

[0486] 0.2μm ≤ t1 - t3 ≤ 4.5μm. It can be understood that the value of t1 - t3 can be 0.2μm, 4.5μm, or any value between 0.2μm and 4.5μm; for example, the value of t1 - t3 can be, but is not limited to, 0.2μm, 0.3μm, 0.1μm, 0.5μm, 1μm, 1.5μm, 1.75μm, 2μm, 3μm, 4μm, 4.5μm.

[0487] By adopting the technical solution of this embodiment, with the design of 0.2μm ≤ t1 - t3 ≤ 4.5μm, the thickening degree of the transition part 1211 is reasonable. On the basis of improving the current - carrying capacity, it can also prevent the thickness of the transition part 1211 from being too large, thus occupying less space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0488] In some embodiments, 0.3μm ≤ t1 - t3 ≤ 1.75μm.

[0489] By adopting the technical solution of this embodiment, with the design of 0.3μm ≤ t1 - t3 ≤ 1.75μm, the thickening degree of the transition part 1211 is more reasonable, the current - carrying capacity is better, and it is also more beneficial to improving the energy density of the battery cell 100.

[0490] In some embodiments, 1 < t1 / t3 ≤ 4. Optionally, 1.5 < t1 / t3 ≤ 2.5.

[0491] t1 / t3 may refer to the ratio of the thickness t1 of the transition part 1211 to the thickness t3 of the second sub - part 12122, and can also characterize the thickening degree of the transition part 1211.

[0492] 1 < t1 / t3 ≤ 4. It can be understood that the value of t1 / t3 can be 4 or any value between 1 and 4; for example, the value of t1 / t3 can be, but is not limited to, 1.1, 1.5, 2, 2.5, 3, 3.5, 4.

[0493] By adopting the technical solution of this embodiment, with the design of 1 < t1 / t3 ≤ 4, the thickening degree of the transition part 1211 is reasonable. On the basis of improving the current - carrying capacity, in addition, the thickness of the transition part 1211 is not too large to occupy a large amount of space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0494] In some embodiments, 1.5 < t1 / t3 ≤ 2.5.

[0495] By adopting the technical solution of this embodiment, with the design of 1.5 < t1 / t3 ≤ 2.5, the thickening degree of the transition part 1211 is more reasonable, the current-carrying capacity is better, and it is also more conducive to improving the energy density of the battery cell 100.

[0496] In some embodiments, 1μm ≤ t1 ≤ 5μm.

[0497] For 1μm ≤ t1 ≤ 5μm, it can be understood that the value of t1 can be 1μm, 5μm, or any value between 1μm and 5μm; by way of example, the value of t1 can be, but is not limited to, 1μm, 1.1μm, 1.2μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 5μm.

[0498] By adopting the technical solution of this embodiment, with the design of 1μm ≤ t1 ≤ 5μm, the thickness design of the transition part 1211 is reasonable, which is conducive to improving the current-carrying capacity. In addition, the thickness of the transition part 1211 is not too large to occupy a large space and weight, which is conducive to improving the energy density of the battery cell 100.

[0499] In some embodiments, 1.2μm ≤ t1 ≤ 3.5μm.

[0500] By adopting the technical solution of this embodiment, with the design of 1.2μm ≤ t1 ≤ 3.5μm, the thickness design of the transition part 1211 is more reasonable, the current-carrying capacity is better, and it is also more conducive to improving the energy density of the battery cell 100.

[0501] In some embodiments, 0.03 ≤ t6 / t5 ≤ 0.95.

[0502] t6 / t5 can refer to the ratio of the thickness of the third protection part 133 to the thickness of the second protection part 132, which can characterize the thinning degree of the third protection part 133 relative to the second protection part 132.

[0503] For 0.03 ≤ t6 / t5 ≤ 0.95, it can be understood that the value of t6 / t5 can be 0.03, 0.95, or any value between 0.03 and 0.95; by way of example, the value of t6 / t5 can be, but is not limited to, 0.03, 0.1, 0.125, 0.15, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95.

[0504] By adopting the technical solution of this embodiment, with the design of 0.03 ≤ t6 / t5 ≤ 0.95, the thinning degree of the conductive protection layer 13 is reasonable, which can be well adapted to the thickening degree of the transition part 1211, is conducive to the surface of the conductive protection layer 13 facing away from the metal layer 12 approaching a plane, is conducive to reducing the rolling damage, and improving the current-carrying capacity of the metal layer 12.

[0505] In some embodiments, 0.125 ≤ t6 / t5 ≤ 0.8.

[0506] By adopting the technical solution of this embodiment, with the design of 0.03 ≤ t6 / t5 ≤ 0.95, the thinning degree of the conductive protection layer 13 is more reasonable, and it can better adapt to the thickening degree of the transition part 1211, which is beneficial to making the surface of the conductive protection layer 13 facing away from the metal layer 12 approach a plane, beneficial to reducing roll pressing damage, and improving the current-carrying capacity of the metal layer 12.

[0507] In some embodiments, 0.5 μm ≤ t6 ≤ 4 μm.

[0508] For 0.5 μm ≤ t6 ≤ 4 μm, it can be understood that the value of t6 can be 0.5 μm, 4 μm, or any value between 0.5 μm and 4 μm; for example, the value of t6 can be but is not limited to 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm.

[0509] By adopting the technical solution of this embodiment, with the setting of 0.5 μm ≤ t6 ≤ 4 μm, the third protection part 133 has a certain thickness, thereby reducing the risk of cracking of the metal layer 12; in addition, it will not cause the third protection part 133 to protrude from the second protection part 132 away from the metal layer 12 due to being too thick, and can also reduce material accumulation and production cost.

[0510] In some embodiments, 1 μm ≤ t6 ≤ 2 μm.

[0511] By adopting the technical solution of this embodiment, with the setting of 1 μm ≤ t6 ≤ 2 μm, the third protection part 133 has a more reasonable thickness, thereby better reducing the risk of cracking of the metal layer 12 and production cost.

[0512] In some embodiments, along the first direction, the size of the first sub-part 12121 is W1, and the size of the second sub-part 12122 is W2, where W1 / (W1 + W2) ≤ 0.45.

[0513] For example, the size W1 of the first sub-part 12121 may refer to the width of the first sub-part 12121, and the size W2 of the second sub-part 12122 may refer to the width of the second sub-part 12122. W1 + W2 may refer to the width of the conductive part 1212.

[0514] W1 / (W1 + W2) may refer to the proportion of the first sub-part 12121 occupying the conductive part 1212 in the width direction of the first pole piece 1.

[0515] W1 / (W1 + W2) ≤ 0.45. It can be understood that the value of W1 / (W1 + W2) can be 0.45 and any value between 0 and 0.45; for example, the value of W1 / (W1 + W2) can be, but is not limited to, 0.001, 0.1, 0.2, 0.3, 0.4, 0.45.

[0516] By adopting the technical solution of this embodiment, the design of W1 / (W1 + W2) ≤ 0.45 enables the active material layer 20 to cover the first sub - part 12121, so as to improve the over - current capacity and reduce the heat generation of the battery cell 100; in addition, along the second direction, the first sub - part 12121 does not occupy too much area, which is beneficial to reducing the occupied space and weight of the first sub - part 12121 and improving the energy density of the battery cell 100.

[0517] In some embodiments, along the first direction, the size of the first sub - part 12121 is W2, where 10 mm ≤ W2 ≤ 100 mm.

[0518] It can be understood that the value of W2 can be 10 mm, 100 mm and any value between 10 mm and 100 mm; for example, the value of W2 can be, but is not limited to, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm.

[0519] By adopting the technical solution of this embodiment, the design of 10 mm ≤ W2 ≤ 100 mm enables the active material layer 20 to cover the first sub - part 12121, so as to improve the over - current capacity and reduce the heat generation of the battery cell 100; in addition, along the second direction, the first sub - part 12121 does not occupy too much area, which is beneficial to reducing the occupied space and weight of the first sub - part 12121 and improving the energy density of the battery cell 100.

[0520] The battery cell 100 of the present application will be described below in conjunction with some embodiments.

[0521] Embodiment 1

[0522] In this embodiment, as shown in Figures 3 - 10 the battery cell 100 includes an end cap 201, a housing 202 and an electrode assembly 101. The electrode assembly 101 is installed at the housing 202, and the end cap 201 covers the opening of the housing 202 to seal the housing 202. The end cap 201 is provided with an electrode lead - out portion 2011.

[0523] In this embodiment, the electrode assembly 101 includes a first electrode tab 1, a second electrode tab 2, and a separator 3 that are wound. The separator 3 is located between the first electrode tab 1 and the second electrode tab 2. The polarities of the first electrode tab 1 and the second electrode tab 2 are opposite. Among them, the first electrode tab 1 can be a positive electrode tab, and the second electrode tab 2 is a negative electrode tab.

[0524] In this embodiment, the first electrode tab 1 includes a current collector 10, an active material layer 20, and a conductive member 30. The current collector 10 includes an insulating substrate 11, a metal layer 12, and a conductive protective layer 13. The metal layer 12 covers opposite surfaces of the insulating substrate 11 in the thickness direction. The conductive protective layer 13 covers the surface of the metal layer 12 facing away from the insulating substrate. The active material layer 20 covers the surface of the conductive protective layer 13 facing away from the insulating substrate.

[0525] In this embodiment, the two metal layers 12 are both welded with a conductive member 30. The conductive member 30 includes a first connection portion 31 and a second connection portion 32 that are connected. The first connection portion 31 is welded to the metal layer 12 to form a first weld mark 51. The second connection portions 32 of the two conductive members 30 are welded to form a second weld mark 52.

[0526] In this embodiment, the electrode assembly 101 further includes an insulating member 40. The insulating member 40 includes a first insulating portion 41. The first insulating portion 41 is located between the first connection portion 31 and the active material layer 20.

[0527] In this embodiment, the metal layer 12 includes a main body portion 121 and at least one protruding portion 122. The main body portion 121 includes a transition portion 1211 and a conductive portion 1212. The transition portion 1211 is connected between the conductive portion 1212 and the protruding portion 122. The protruding portion 122 protrudes from the transition portion 1211 in a first direction perpendicular to the thickness direction of the current collector 10. The active material layer 20 covers the conductive portion 1212. The protruding portion 122 and the transition portion 1211 are not covered with the active material layer 20.

[0528] In this embodiment, the number of the protruding portions 122 is multiple. The multiple protruding portions 122 are arranged at intervals in a second direction perpendicular to the first direction and the thickness direction of the current collector 10.

[0529] In this embodiment, the protruding portion 122 includes a first protruding sub-portion 1221 and a second protruding sub-portion 1222. The first protruding sub-portion 1221 is connected between the second protruding sub-portion 1222 and the transition portion. The dimension of the second protruding sub-portion 1222 in the second direction is smaller than the dimension of the first protruding sub-portion 1221 in the second direction. The first protruding sub-portion 1221 is welded to the first connecting portion 31 to form a first welding mark sub-portion 5111, and the second protruding sub-portion 1222 is welded to the first connecting portion 31 to form a second welding mark portion 5112. The first welding mark sub-portion 5111 and the second welding mark sub-portion 5112 form a first welding mark portion 511, that is, the first welding mark portion 511 is the first welding mark 51.

[0530] In this embodiment, along the second direction, the sum l1 of the dimensions of the first protruding sub-portions 1221 of all the protruding portions 122 is more than 0.5 times the dimension l2 of the main body portion 121.

[0531] Embodiment Two

[0532] The difference between this embodiment and Embodiment One is as follows: Refer to Figures 11 - 17 As shown, the protruding portion 122 includes a first protruding sub-portion 1221. The first connecting portion 31 is welded to the first protruding sub-portion 1221 to form a first welding mark portion 511, and the first connecting portion 31 is welded to the transition portion 1211 to form a second welding mark portion 512. The first welding mark portion 511 and the second welding mark portion 512 form the first welding mark 51.

[0533] The insulating member 40 further includes a second insulating portion 42. One side of the second insulating portion 42 covers the first welding mark 51 and the second welding mark 52, and the other side covers the first insulating portion 41.

[0534] In this embodiment, the protruding portion 122 is welded to the first connecting portion 31 to form a first welding mark portion 511, and the transition portion 1211 is welded to the first connecting portion 31 to form a second welding mark portion 512; the first welding mark portion 511 and the second welding mark portion 512 form the first welding mark 51.

[0535] Embodiment Three

[0536] The difference between this embodiment and Embodiment Two is as follows: Refer to Figures 18 - 21 As shown, the insulating member 40 includes a second insulating portion 42 and does not include the first insulating portion 41. One side of the second insulating portion 42 covers the first welding mark 51, and the other side of the second insulating portion 42 covers the active material layer 20.

[0537] In some embodiments, refer to Figure 2 As shown, a battery device 1100 is provided, including the battery cell 100 of the above embodiment.

[0538] The battery device 1100 according to the embodiment of the present application uses the above-mentioned battery cell 100. The battery cell 100 has good fast charging performance and good use reliability, which is beneficial to improving the fast charging performance of the battery device 1100 and also beneficial to improving the use reliability of the battery device 1100.

[0539] In some embodiments, referring to Figure 1 as shown, an electrical device is provided, including the battery device 1100 as described in the above embodiment.

[0540] The battery device 1100 according to the embodiment of the present application uses the above-mentioned battery device 1100. The battery device 1100 has good fast charging performance and good use reliability, which is beneficial to improving the endurance of the electrical device and also beneficial to improving the use reliability of the electrical device.

[0541] The descriptions of the above embodiments tend to emphasize the differences between the embodiments. The same or similar parts can be referred to each other. For the sake of brevity, they will not be repeated herein.

[0542] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A housing having an electrode lead-out portion; an electrode assembly, at least partially contained in the housing, the electrode assembly comprising a first pole piece, the first pole piece comprising a conductive member, a current collector and an active material layer; The conductive member is connected to the electrode lead-out portion; the current collector includes an insulating substrate and a metal layer, the insulating substrate, the metal layer and the active material layer are stacked along the thickness direction of the current collector, and at least a portion of the metal layer is located between the insulating substrate and the active material layer; The metal layer includes a main body and at least one protrusion, the protrusion extending outward from an end of the main body along a first direction, the first direction is perpendicular to the thickness direction of the current collector, and each of the protrusions is connected to the conductive member; at least a portion of the main body is covered with the active material layer, and at least a portion of the protrusion is not covered with the active material layer; The protrusion includes a first protrusion sub-portion connected to the main body; along the second direction, the sum of the sizes of the first protrusion sub-portions of all the protrusions is more than 0.5 times the size of the main body, wherein the second direction is perpendicular to the first direction and the thickness direction of the collector.

2. The battery cell according to claim 1, characterized in that: Along the second direction, the sum of the sizes of the first protruding sub-portions of all the protruding portions is greater than 0.6 times the size of the main body portion.

3. The battery cell according to claim 1, characterized in that: The conductive member includes a first connection portion and at least one second connection portion, the first connection portion and the second connection portion are arranged along the first direction, the first connection portion and the second connection portion are connected, the second connection portion is connected to the electrode lead portion, the first connection portion is welded to the surface of the metal layer facing away from the insulating substrate to form a first weld mark, and the second connection portion is located on the side of the protruding portion facing away from the main body; Along the first direction, the first weld mark is located on a side of the active material layer facing the protruding portion.

4. The battery cell according to claim 3, characterized in that: The first weld print includes a first weld print portion, and the first connection portion is welded to a surface of the protruding portion facing away from the insulating substrate to form the first weld print portion.

5. The battery cell according to claim 4, characterized in that: Along the second direction, the first welding portion extends from one side of the protruding portion to the other side of the protruding portion.

6. The battery cell according to claim 4, characterized in that: The protruding portion further includes a second protruding sub-portion, wherein the first protruding sub-portion is connected between the second protruding sub-portion and the main body portion; Along the second direction, the size of the first protruding sub-portion is greater than the size of the second protruding sub-portion; The first weld print portion includes a first weld print sub-portion, and the first connection portion is welded to the first protruding sub-portion to form the first weld print sub-portion.

7. The battery cell according to claim 6, characterized in that: Along the second direction, the first weld sub-portion extends from one side of the first protruding sub-portion to the other side of the first protruding sub-portion.

8. The battery cell according to claim 6, characterized in that: The first weld print portion further includes a second weld print sub-portion, and the first connection portion is welded to a surface of the second protruding sub-portion facing away from the insulating substrate to form the second weld print sub-portion.

9. The battery cell according to claim 8, characterized in that: Along the second direction, the second weld sub-portion extends from one side of the second protruding sub-portion to the other side of the second protruding sub-portion.

10. The battery cell according to any one of claims 3 to 9, characterized in that: There are multiple protrusions, which are arranged at intervals along the second direction, and each of the protrusions is welded to the first connecting portion.

11. The battery cell according to claim 10, characterized in that: The first connection portion includes a plurality of first connection sub-portions, the plurality of first connection sub-portions are arranged at intervals along the second direction, the number of the second connection portions is multiple, and each of the first connection sub-portions is connected to each of the second connection portions in a one-to-one correspondence; The first connecting sub-portions are welded one by one to the surface of the protruding portions facing away from the insulating substrate.

12. The battery cell according to any one of claims 3 to 9, characterized in that: The main body includes a transition portion and a conductive portion, the transition portion is connected between the protruding portion and the conductive portion, the conductive portion is covered with the active material layer, and the transition portion and the protruding portion are not covered with the active material layer; the first connecting portion is connected to the surface of the transition portion facing away from the insulating substrate.

13. The battery cell according to claim 12, characterized in that: Along the second direction, the size of the conductive portion is L1, the size of the transition portion is L2, and 0.8≤L2 / L1≤1.

14. The battery cell according to claim 12, characterized in that: The first weld print includes a second weld print portion, and the first connection portion is welded to a surface of the transition portion facing away from the insulating substrate to form the second weld print portion.

15. The battery cell according to claim 14, characterized in that: Along the second direction, the size of the transition portion is L2, the size of the second weld portion is L3, and 0.8≤L3 / L2≤1.

16. The battery cell according to claim 12, characterized in that: There are multiple protrusions, and the multiple protrusions are arranged at intervals along the second direction; The first connecting portion includes a second connecting sub-portion and a plurality of first connecting sub-portions, the plurality of first connecting sub-portions are arranged at intervals along the second direction, and the first connecting sub-portions are welded one by one to the surface of each protruding portion facing away from the insulating substrate; There are multiple second connection parts, and along the first direction, one side of each first connection sub-part is connected to each second connection part in a one-to-one correspondence, and the other side of each first connection sub-part is connected to the second connection sub-part, and the second connection sub-parts are continuously arranged along the second direction; The second connecting sub-portion is welded to a surface of the transition portion facing away from the insulating substrate.

17. The battery cell according to any one of claims 3 to 9, characterized in that: Along the first direction, the first connection portion is spaced apart from the active material layer.

18. The battery cell according to any one of claims 3 to 9, characterized in that: The electrode assembly further includes an insulating member, which includes a first insulating portion, the first insulating portion covers a surface of the metal layer facing away from the insulating substrate, and the entire first insulating portion is located between the first weld print and the active material layer.

19. The battery cell according to claim 18, characterized in that: The first insulating portion is located between the first connecting portion and the active material layer.

20. The battery cell according to claim 19, characterized in that: The insulating member further includes a second insulating portion, at least a portion of the second insulating portion covers the first weld mark.

21. The battery cell according to claim 20, characterized in that: Along the first direction, one side of the second insulating portion covers the first weld mark, and the other side of the second insulating portion covers at least a portion of the first insulating portion.

22. The battery cell according to claim 3, characterized in that: The electrode assembly further includes an insulating member, wherein the insulating member includes a second insulating portion, and at least a portion of the second insulating portion covers the first weld mark.

23. The battery cell according to claim 22, characterized in that: Along the first direction, one side of the second insulating portion covers the first weld mark, and the other side of the second insulating portion covers at least a portion of the active material layer.

24. The battery cell according to any one of claims 20 to 23, characterized in that: The number of the metal layers is two, and the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector. The number of the active material layers is two, and the two active material layers cover the two metal layers respectively. There are two conductive members, and the first connection portions of the two conductive members are respectively welded to the surfaces of the two metal layers facing away from the insulating substrate to form two first weld marks; The number of the insulating members is two, and the second insulating parts of the two insulating members respectively cover at least a portion of the two first weld marks.

25. The battery cell according to claim 24, characterized in that: The second insulating portion includes a first portion and a second portion connected to each other, wherein the first portion covers at least a portion of the main body portion, and the second portion protrudes from the main body portion along a direction from the main body portion toward the protruding portion, and the second portion is located on a side of the protruding portion along the second direction.

26. The battery cell according to claim 25, characterized in that: The second parts of the two insulating members are in contact with each other.

27. The battery cell according to claim 24, characterized in that: The second connection portions of the two conductive members are welded to form a second weld mark.

28. The battery cell according to claim 27, characterized in that: The second insulating portion covers the second weld mark, and is along a direction from the main body to the protruding portion, and the second insulating portion protrudes from an edge of the second weld mark facing away from the main body.

29. The battery cell according to claim 18, characterized in that: The electrode assembly comprises a second pole piece having a polarity opposite to that of the first pole piece, the second pole piece comprises a main functional portion and a pole ear portion, the pole ear portion protruding from the main functional portion along the first direction; Along the direction from the main body to the protruding portion, the main functional portion protrudes from the end surface of the insulating member facing the active material layer, and the main functional portion does not protrude from the end surface of the insulating member away from the active material layer.

30. The battery cell according to any one of claims 3 to 9, characterized in that: The distance between the first weld mark and the active material layer is S1, wherein 0.3 mm ≤ S1 ≤ 5 mm, and optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

31. The battery cell according to any one of claims 3 to 9, characterized in that: The current collector further includes a conductive protective layer, at least a portion of which is located between the active material layer and the metal layer, and along the first direction, the conductive protective layer and the first weld print are spaced apart.

32. The battery cell according to any one of claims 1 to 9, characterized in that: The electrode assembly comprises a second pole piece having a polarity opposite to that of the first pole piece, the second pole piece comprises a main functional portion and a pole ear portion, the pole ear portion protruding from the main functional portion along the first direction; Along the direction from the main body portion to the protruding portion, the main functional portion protrudes from an end portion of the main body portion facing the protruding portion.

33. The battery cell according to any one of claims 1 to 9, characterized in that: The current collector further includes a conductive protection layer, at least a portion of which is located between the active material layer and the metal layer.

34. The battery cell according to claim 33, characterized in that: Along the direction from the main body to the protruding portion, the conductive protection layer protrudes from the end surface of the active material layer facing the protruding portion.

35. The battery cell according to claim 34, characterized in that: Along the direction from the main body to the protruding portion, the conductive protection layer protrudes from the end surface of the active material layer toward the protruding portion by a distance ranging from 0.3 mm to 0.8 mm.

36. The battery cell according to any one of claims 1 to 9, characterized in that: The main body portion includes a transition portion and a conductive portion, the transition portion is connected between the protruding portion and the conductive portion, the conductive portion is covered with the active material layer, and the transition portion is not covered with the active material layer; the transition portion is connected to the conductive component; the thickness of at least part of the conductive portion is smaller than the thickness of the transition portion.

37. The battery cell according to claim 36, characterized in that: The conductive portion includes a first sub-portion and a second sub-portion, the first sub-portion is connected between the second sub-portion and the transition portion, the first sub-portion and the second sub-portion are covered with the active material layer, the thickness of the first sub-portion is greater than the thickness of the second sub-portion, and the thickness of the transition portion is greater than or equal to the thickness of the first sub-portion.

38. The battery cell according to claim 37, characterized in that: The current collector also includes a conductive protective layer, which includes a first protective portion and a second protective portion, wherein the first protective portion is located between the first sub-portion and the active material layer, and the second protective portion is located between the second sub-portion and the active material layer; wherein the thickness of the first protective portion is less than the thickness of the second protective portion.

39. The battery cell according to claim 38, characterized in that: The conductive protection layer further includes a third protection portion, the third protection portion covers a surface of the transition portion facing away from the insulating substrate, and a thickness of the third protection portion is less than or equal to a thickness of the first protection portion.

40. The battery cell according to claim 36, characterized in that: The thickness of the protruding portion is greater than or equal to the thickness of the transition portion.

41. A battery device, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 40.

42. An electrical device, characterized in that: A battery device comprising the battery device of claim 41.

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