Battery monomer, battery device and electric device

Abstract

The utility model belongs to the technical field of battery insulation, and particularly relates to a single battery, a battery device and a power utilization device. The shell is provided with an electrode leading-out part; the electrode assembly is accommodated in the shell, the electrode assembly comprises a first pole piece and an insulating part, and the first pole piece comprises a conductive component, a current collector and an active substance layer; the current collector comprises an insulating substrate and a metal layer; the conductive component is connected with the electrode lead-out part and the metal layer; the metal layer is positioned between the insulating substrate and the active material layer; the metal layer comprises a main body part and at least one protruding part, the protruding part extends outwards from the end part of the main body part along a first direction, and the first direction is perpendicular to the thickness direction of the current collector; the main body part is covered with an active material layer, and the protruding part is not covered with the active material layer; the insulating part comprises a first insulating part which is positioned on the side part, back to the insulating substrate, of the main body part; the first insulation part protrudes out of the end part, facing the protruding part, of the main body part in the direction from the main body part to the protruding part.

Description

Technical Field

[0001] This application belongs to the technical field of battery insulation, 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 capacitance usage requirements; however, in the technology of battery cells, how to improve the usage reliability 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 improving the usage reliability of battery cells.

[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, and the electrode assembly includes a first electrode plate and an insulating member. The first electrode plate includes a conductive member, a current collector, and an active material layer; the current collector includes an insulating matrix and a metal layer, and the conductive member connects the electrode lead-out portion and the metal layer; the insulating matrix, the metal layer, and the active material layer are stacked along the thickness direction of the current collector, and at least a part of the metal layer is located between the insulating matrix 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, and the first direction is perpendicular to the thickness direction of the current collector; at least a part 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 insulating member includes a first insulating portion, and the first insulating portion is located on a side of the main body portion facing away from the insulating matrix; along the direction from the main body portion to the protruding portion, the first insulating portion protrudes from an end of the main body portion facing the protruding portion.

[0008] For the battery cell of the embodiment of the present application, the first insulating part can prevent burrs at the end face of the main body part facing the protruding part from piercing the separator and contacting the second pole piece, thereby reducing the short-circuit risk of the battery cell and being beneficial to improving the use reliability of the battery cell. Additionally, 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 are small, reducing the internal short-circuit risk 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 overcurrent capacity and use reliability.

[0009] In one embodiment, 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 a 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 close to the protruding part.

[0010] 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 production of the first pole piece. Additionally, the thickness of the metal layer is small, and the surface of the metal layer facing away from the insulating matrix is large, which is beneficial to increasing the welding area between the conductive member and the metal layer, increasing the overcurrent area between the conductive member and the metal layer, being beneficial to improving the overcurrent capacity of the first pole piece, and improving the fast charging performance of the battery cell. The second connection part protrudes outside the main body part, which facilitates the connection between the second connection part and the electrode lead-out part, and the processing and production are more convenient. At the same time, it can also reduce the risk of problems such as false soldering, being beneficial to improving the connection reliability between the metal layer and the conductive member, and also being beneficial to improving the overcurrent capacity of the first pole piece and the fast charging performance of the battery cell.

[0011] In one embodiment, the first insulating part covers at least a part of the first welding mark.

[0012] By adopting the technical solution of this embodiment, the first insulating part can prevent components such as tip protrusions and metal debris on the surface of the first welding mark from piercing the separator and connecting to the second pole piece, reducing the short-circuit risk of the battery cell and improving the use reliability of the battery cell.

[0013] In one embodiment, along the first direction, the first connection part and the active material layer are arranged at intervals.

[0014] By adopting the technical solution of this embodiment, the first connection part does not contact the active material layer, which can reduce the mutual influence between the two and improve the use reliability of the battery cell.

[0015] In one embodiment, the insulating member includes a second insulating portion that covers the surface of the metal layer facing away from the insulating substrate, and the entire second insulating portion is located between the first solder pad and the active material layer.

[0016] By adopting the technical solution of this embodiment, it is beneficial to reduce the risk of false soldering between the first connecting portion and the metal layer, improve the connection reliability between the first connecting portion and the metal layer, and also beneficial to improve the overcurrent capacity.

[0017] In one embodiment, the second insulating portion is located between the first connecting portion and the active material layer.

[0018] By adopting the technical solution of this embodiment, the second insulating portion can support the part of the metal layer located between the first connecting portion and the active material layer, reduce damages such as cracks and fractures that occur in this part during the manufacturing process of the battery device, be beneficial to improving the electron transport capacity of this part, improving the fast charging performance and service reliability of the battery cell; in addition, the first insulating portion can also insulate this part, reduce the short-circuit risk of the battery cell, and improve the service reliability of the battery cell.

[0019] In one embodiment, along the first direction, one side of the first insulating portion covers the first solder pad, and the other side of the first insulating portion covers at least part of the second insulating portion.

[0020] By adopting the technical solution of this embodiment, the second insulating portion and the first insulating portion jointly cover the metal layer, which can achieve double-layer insulation, be beneficial to reducing the short-circuit risk of the battery cell, and be beneficial to improving the service reliability of the battery cell.

[0021] In one embodiment, along the first direction, one side of the first insulating portion covers the first solder pad, and the other side of the first insulating portion covers at least part of the active material layer.

[0022] By adopting the technical solution of this embodiment, the first insulating portion extends from the first solder pad to the active material layer, and the coverage area of the first insulating portion is wide and the insulation effect is good, which is beneficial to improving the service reliability of the battery cell.

[0023] In one embodiment, the first solder pad includes a first solder pad portion, the first connecting portion is welded to the surface of the protruding portion facing away from the insulating substrate to form the first solder pad portion, and the first insulating portion covers at least part of the first solder pad portion.

[0024] By adopting the technical solution of this embodiment, the first connecting portion and the protruding portion are connected by welding. The connection method is simple and convenient for the production of the first pole piece. The first connecting portion and the protruding portion can directly use the first welding mark portion for current conduction, which is beneficial to improving the current-carrying capacity between the first connecting portion and the protruding portion. The first insulating portion can prevent components such as burrs and metal debris on the first welding mark portion from passing through the separator and connecting with the second pole piece, which is beneficial to improving the use reliability of the battery cell.

[0025] In one embodiment, the first welding mark portion includes a first welding mark sub-portion, the protruding portion includes a first protruding sub-portion and 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, and the second direction is perpendicular to the first direction and the thickness direction of the current collector. The first connecting portion is welded to the surface of the first protruding sub-portion facing away from the insulating substrate to form the first welding mark sub-portion, and the first insulating portion covers at least a part of the first welding mark sub-portion.

[0026] By adopting the technical solution of this embodiment, the first connecting portion is welded to the first protruding sub-portion to form the first welding mark sub-portion. The large size of the first protruding sub-portion along the second direction is beneficial to increasing the welding area between the protruding portion and the first connecting portion, increasing the current-carrying area between the protruding portion and the first connecting portion, improving the current-carrying capacity, reducing the heat generation of the battery cell, and being beneficial to improving the fast charging performance and use reliability of the battery cell. In addition, along the second direction, the small size of the second protruding sub-portion is beneficial to reducing the occupied space of the protruding portion and being beneficial to improving the energy density of the battery cell. In addition, the first insulating portion can prevent components such as burrs and metal debris on the first welding mark sub-portion from passing through the separator and connecting with the second pole piece, which is beneficial to improving the use reliability of the battery cell.

[0027] In one embodiment, along the direction from the main body portion to the protruding portion, the first insulating portion protrudes from the end surface of the first protruding sub-portion facing away from the main body portion.

[0028] By adopting the technical solution of this embodiment, along the second direction, the large size of the first welding mark sub-portion is beneficial to increasing the welding area between the protruding portion and the first connecting portion, increasing the current-carrying area between the protruding portion and the main body portion, improving the current-carrying capacity, reducing the heat generation of the battery cell, and being beneficial to improving the fast charging performance and use reliability of the battery cell.

[0029] In one embodiment, along the second direction, the first welding 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.

[0030] By adopting the technical solution of this embodiment, along the second direction, the size of the first welding mark sub - part is large, which is beneficial to increasing the welding area between the protruding part and the first connecting part, increasing the current - carrying area between the protruding part and the main body part, improving the current - carrying capacity, reducing the heat generation of the battery cell, and being beneficial to improving the fast - charging performance and service reliability of the battery cell.

[0031] In one embodiment, the first welding mark part further includes a second welding mark sub - part. The first connecting part is welded to the surface of the second protruding sub - part facing away from the insulating matrix to form the second welding mark sub - part, and the first insulating part covers at least part of the second welding mark sub - part.

[0032] By adopting the technical solution of this embodiment, the second protruding sub - part is also welded to the first connecting part, which is beneficial to increasing the current - carrying area between the first connecting part and the protruding part and improving the current - carrying capacity between the first connecting part and the protruding part. In addition, the first insulating part can prevent burrs, metal debris and other components on the second welding mark sub - part from passing through the separator and connecting to the second pole piece, which is beneficial to improving the service reliability of the battery cell.

[0033] In one embodiment, along the direction from the main body part to the protruding part, the first insulating part protrudes from the edge of the second welding mark sub - part facing away from the first protruding sub - part.

[0034] By adopting the technical solution of this embodiment, the first insulating part can completely cover the second welding mark sub - part and the first welding mark sub - part, reducing the risk of short - circuit caused by burrs, metal debris and other components on the second welding mark sub - part and the first welding mark sub - part, which is beneficial to improving the service reliability of the battery cell.

[0035] In one embodiment, along the second direction, the second welding mark sub - part extends from one side edge of the second protruding sub - part to the other side edge of the second protruding sub - part.

[0036] By adopting the technical solution of this embodiment, the size of the second welding mark sub - part along the second direction is large, which is beneficial to increasing the welding area between the first connecting part and the protruding part, increasing the current - carrying area between the first connecting part and the protruding part, and being beneficial to improving the current - carrying capacity between the first connecting part and the protruding part.

[0037] In one embodiment, the number of protruding parts is multiple. The multiple protruding parts are arranged at intervals along the second direction. Each protruding part is welded to the first connecting part, and the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0038] By adopting the technical solution of this embodiment, a plurality of protruding parts are arranged at intervals in the second direction, which is conducive to dividing the main body part into a plurality of regions in the second direction, and one region can correspond to one protruding part. Electrons in each region can be transmitted to the electrode lead-out part through the corresponding protruding part, so that the electrons in the main body part are transmitted in sub-regions. The electron transmission path in each region to the corresponding protruding part is short, which is conducive to reducing the electron transmission distance, reducing the overall resistance of the first pole piece, and improving the fast charging performance and use reliability of the battery cell.

[0039] In some embodiments, the first connecting part includes a plurality of first connecting sub-parts, the plurality of first connecting sub-parts are arranged at intervals in the second direction, the number of the second connecting parts is plural, and each first connecting sub-part is connected to each second connecting part in one-to-one correspondence; each first connecting sub-part is welded to the surface of each protruding part facing away from the insulating matrix.

[0040] By adopting the technical solution of this embodiment, the plurality of first connecting sub-parts of the first connecting part are arranged at intervals in the second direction, and there is a gap between two adjacent first connecting sub-parts, which can reduce the material required for the first connecting part and reduce the manufacturing cost of the battery cell.

[0041] In one embodiment, the main body part includes a conductive part and a transition part, the transition part is connected between the conductive part and the protruding part, the transition part and the protruding part are not covered with an active material layer, and the conductive part is covered with an active material layer; the first insulating part covers at least part of the surface of the transition part facing away from the insulating matrix; along the direction from the main body part to the protruding part, the first insulating part protrudes from the end of the transition part facing away from the conductive part.

[0042] By adopting the technical solution of this embodiment, the surface of the transition part of the main body part facing away from the insulating matrix is connected to the first connecting part, so that a part of the current can flow directly into or out of the first connecting part through the transition part, reducing the overcurrent pressure between the protruding part and the main body part, which is conducive to reducing the heat generation at the first protruding sub-part and improving the fast charging performance and use reliability of the battery cell.

[0043] In one embodiment, along the second direction, the size of the conductive part is L1, the size of the transition part is L2, and 0.8≤L2 / L1≤1, where the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0044] By adopting the technical solution of this embodiment, the size of the transition part in the second direction is large, which is conducive to increasing the connection area between the first connecting part and the transition part, improving the overcurrent capacity at the connection between the first connecting part and the transition part, improving 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.

[0045] In one embodiment, the first welding mark further includes a second welding mark portion. The first connecting portion is welded to the surface of the transition portion facing away from the insulating substrate to form the second welding mark portion, and the first insulating portion covers at least a part of the second welding mark portion.

[0046] By adopting the technical solution of this embodiment, the first connecting portion and the transition portion are connected by welding, and the connection method is simple, which is beneficial to the production of the first pole piece. In addition, the second welding mark portion can be directly used for current conduction between the first connecting portion and the transition portion, which is beneficial to improving the current-carrying capacity between the first connecting portion and the transition portion and reducing the heat generation of the battery cell. In addition, the first insulating portion can prevent burrs, metal debris and other components on the second welding mark portion from passing through the separator and connecting with the second pole piece, which is beneficial to improving the use reliability of the battery cell.

[0047] In one embodiment, along the direction from the protruding portion to the main body portion, the first insulating portion protrudes from the edge of the second welding mark portion facing the active material layer.

[0048] By adopting the technical solution of this embodiment, the first insulating portion can completely cover the second welding mark portion, and the first insulating portion can prevent burrs, metal debris and other components on the entire second welding mark portion from passing through the separator and connecting with the second pole piece, which is beneficial to improving the use reliability of the battery cell.

[0049] In one embodiment, along the second direction, the size of the transition portion is L2, and the size of the second welding mark portion is L3, where 0.8 ≤ L3 / L2 ≤ 1. Here, the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0050] By adopting the technical solution of this embodiment, the size of the transition portion along the second direction is relatively large, which is beneficial to increasing the connection area between the first connecting portion and the transition portion, improving the current-carrying capacity at the connection between the first connecting portion and the transition portion, improving the current-carrying capacity of the first pole piece, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell.

[0051] In one embodiment, the number of the protruding portions is multiple, and the multiple protruding portions are arranged at intervals along the second direction, where the second direction is perpendicular to the first direction and the thickness direction of the current collector; the first connecting portion includes a second connecting sub-portion and multiple first connecting sub-portions, and the multiple first connecting sub-portions are arranged at intervals along the second direction. Each first connecting sub-portion is welded to the surface of each protruding portion facing away from the insulating substrate; the number of the second connecting portions is multiple. Along the first direction, one side of each first connecting sub-portion is connected to each second connecting portion in one-to-one correspondence, and the other side of each first connecting sub-portion is connected to the second connecting sub-portion. The second connecting sub-portion is continuously arranged along the second direction; the second connecting sub-portion is welded to the surface of the transition portion facing away from the insulating substrate.

[0052] 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, reduce the risk of the first connecting sub - part being bent when inserted between the first pole piece and the second pole piece, reduce the short - circuit risk, and is beneficial to improving the use reliability 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 use reliability of the battery cell.

[0053] In one embodiment, the number of metal layers is two, and the two metal layers are arranged on opposite sides of the insulating matrix 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 parts of the two conductive members are respectively welded to the surfaces of the two metal layers facing away from the insulating matrix to form two first weld marks. The number of insulating parts is two, and the first insulating parts of the two insulating parts respectively cover at least part of the two first weld marks.

[0054] By adopting the technical solution of this embodiment, the first connection parts of the two conductive members are respectively welded to the metal layers located on opposite sides of the insulating matrix, and the second connection parts of the two conductive members are located on the side of the protruding part facing away from the main body part. In this way, the two metal layers can be directly connected by using the second connection parts of the two conductive members, thereby breaking the insulation limit of the insulating matrix, effectively improving the conductive ability 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's metal layer.

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

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

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

[0058] By adopting the technical solution of this embodiment, after the second parts of the two insulating parts are fitted together, components such as metal debris on the end face of the main body part facing the protruding part can be wrapped, so that components such as metal debris are not easily dropped into the electrode assembly, and the short - circuit risk of the battery cell can be better reduced.

[0059] In one embodiment, the second connecting parts 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 parts 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 one embodiment, the first insulating part covers at least part of the second weld mark.

[0062] By adopting the technical solution of this embodiment, the first insulating part can prevent 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 one embodiment, along the direction from the main body part to the protruding part, the first insulating part protrudes from the edge of the second weld mark away from the main body part.

[0064] By adopting the technical solution of this embodiment, the first insulating part can completely cover the second weld mark, prevent components such as tip protrusions and metal debris on the entire second weld mark from piercing the separator and connecting to the second pole piece, reduce the short - circuit risk, and improve the use reliability of the battery cell.

[0065] In one embodiment, along the first direction, the distance between the first weld mark and the active material layer is S1, where 0.3mm ≤ S1 ≤ 5mm, optionally, 0.5mm ≤ S1 ≤ 2.8mm.

[0066] By adopting the technical solution of this embodiment, the first weld mark will not be welded to the active material layer, reducing problems such as false soldering, which is beneficial to improving the connection reliability between the first connecting part and the metal layer. In addition, since the distance between the active material layer and the first weld mark is small, the active material layer can be relatively close to the first weld mark. Then, when the size of the metal layer in the first direction is fixed, the area that the active material layer can cover is larger, which is beneficial to improving the energy density of the battery cell.

[0067] In one embodiment, the current collector further includes a conductive protection layer, and at least part of the conductive protection layer is located between the active material layer and the metal layer.

[0068] By adopting the technical solution of this embodiment, the conductive protective layer can separate the active material layer and the metal layer while protecting the metal layer, reducing the risks such as cracks generated in the metal layer due to rolling the active material layer, which is beneficial to improving the current-carrying capacity of the metal layer.

[0069] In one embodiment, along the direction from the main body portion towards the protruding portion, the conductive protective layer protrudes from the end face of the active material layer towards the protruding portion.

[0070] By adopting the technical solution of this embodiment, the conductive protective layer can completely separate the active material layer and the metal layer, the protective ability of the conductive protective layer for the metal layer is better, the current-carrying capacity of the first pole piece is better, which is beneficial to improving the fast charging performance and service reliability of the battery cell.

[0071] In one embodiment, along the direction from the main body portion towards the protruding portion, the protruding length range of the conductive protective layer protruding from the end face of the active material layer towards the protruding portion is 0.3 mm to 0.8 mm.

[0072] By adopting the technical solution of this embodiment, the current-carrying capacity and energy density of the battery cell can be better balanced.

[0073] In one embodiment, along the first direction, the conductive protective layer and the first welding mark are arranged at intervals.

[0074] By adopting the technical solution of this embodiment, the first connecting portion will not be welded to the conductive protective layer, which can reduce the risks such as false soldering, and is beneficial to improving the welding reliability between the first connecting portion and the metal layer.

[0075] In one embodiment, along the first direction, the size of the part of the insulating member covering the active material layer is H, where 0.2 mm ≤ H ≤ 1.0 mm, optionally, 0.3 mm ≤ H ≤ 0.8 mm.

[0076] By adopting the technical solution of this embodiment, along the first direction, the size of the part of the first insulating portion covering the active material layer is reasonable, which can balance the burrs at the end of the main body portion towards the protruding portion and the energy density problem of the battery cell at the same time.

[0077] In one embodiment, the first insulating portion is connected to the first pole piece.

[0078] By adopting the technical solution of this embodiment, the first insulating portion is connected to the first pole piece, and the first insulating portion can be fixed, so as to stably block the burrs at the end of the main body portion towards the protruding portion, which is beneficial to improving the service reliability of the battery cell.

[0079] In one embodiment, the first insulating portion includes an insulating base layer and an adhesive layer, and the adhesive layer is bonded between the insulating base layer and the first pole piece.

[0080] By adopting the technical solution of this embodiment, the first insulating part adopts the structure of an insulating base layer and an adhesive layer. The insulating base layer can improve the structural strength of the first insulating part, reduce the deformation during the fitting process of the first insulating part, and is beneficial to improving the insulation effect; the adhesive layer can stably fix the insulating base layer on the first pole piece and reduce the risk of the insulating tape falling off.

[0081] In one embodiment, the layer thickness range of the insulating base layer is 6μm to 15μm; and / or, the layer thickness range of the adhesive layer is 0.5μm to 3μm.

[0082] By adopting the technical solution of this embodiment, the internal insulation and energy density of the battery cell can be taken into account simultaneously.

[0083] In one embodiment, along the first direction, the size of the insulating part is W, where 3mm ≤ W ≤ 9mm, and optionally, 4.5mm ≤ W ≤ 6.5mm.

[0084] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell can be taken into account simultaneously.

[0085] In one embodiment, the electrode assembly further includes a second pole piece having 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 towards the protruding part, the main functional part protrudes from the end face of the insulating part close to the active material layer, and the main functional part does not protrude from the end face of the insulating part away from the active material layer.

[0086] By adopting the technical solution of this embodiment, the insulating part can prevent the burrs at the end face of the main functional part of the second pole piece near the pole ear part from piercing through the separator and connecting with the first pole piece, reducing the risk of short circuit between the first pole piece and the second pole piece, and being beneficial to improving the use reliability of the battery cell.

[0087] In one embodiment, the electrode assembly further includes a second pole piece having 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 towards the protruding part, the main functional part protrudes from the end of the main body part towards the protruding part.

[0088] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional part of the second pole piece towards 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 risk of short circuit of the battery cell and improve the use reliability of the battery cell.

[0089] In one embodiment, the main body part includes a transition part and a conductive part. The transition part is connected between the protruding part and the conductive part. The conductive part is covered with an active material layer, and the transition part is not covered with an active material layer; the transition part is connected to the conductive member; at least part of the thickness of the conductive part is less than the thickness of the transition part.

[0090] By adopting the technical solution of this embodiment, the thickness of the transition part is relatively large, and the current-carrying capacity of the transition part is good, which is beneficial to improving the current-carrying capacity of the first pole piece, reducing the heat generation of the battery cell, and is beneficial to improving the fast charging performance and service reliability of the battery cell.

[0091] In one embodiment, the conductive part includes a first sub-part and a second sub-part. The first sub-part is connected between the second sub-part and the transition part. The first sub-part and the second sub-part are covered with an active material layer. The thickness of the first sub-part is greater than that of the second sub-part, and the thickness of the transition part is greater than or equal to the thickness of the first sub-part.

[0092] By adopting the technical solution of this embodiment, the current-carrying capacity of the first sub-part close to the transition part is greater than that of the second sub-part far from the transition part. In this way, the restriction on the current can be reduced, the current-carrying capacity of the first pole piece can be improved, the heat generation of the battery cell can be reduced, and it is beneficial to improve the service reliability of the battery cell.

[0093] In one embodiment, the current collector further includes a conductive protection layer. The conductive protection layer includes a first protection part and a second protection part. The first protection part is located between the first sub-part and the active material layer, and the second protection part is located between the second sub-part and the active material layer; wherein, the thickness of the first protection part is less than that of the second protection part.

[0094] By adopting the technical solution of this embodiment, the surface of the conductive protection 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.

[0095] In one embodiment, the conductive protection layer further includes a third protection part. The third protection part covers the surface of the transition part facing away from the insulating substrate, and the thickness of the third protection part is less than or equal to the thickness of the first protection part.

[0096] By adopting the technical aspect of this embodiment, the setting of the third protection part can make the conductive protection 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 protection part is not too large, which is beneficial to reducing the waste of materials and saving the manufacturing cost of the battery cell.

[0097] In one embodiment, the thickness of the protruding part is greater than or equal to the thickness of the transition part.

[0098] By adopting the technical solution of this embodiment, the thickness of the protruding part is relatively thick, which can improve the current-carrying capacity of the protruding part, is beneficial to improving the current-carrying capacity of the first pole piece, reducing the heat generation of the battery cell, and is beneficial to improving the fast charging performance and service reliability of the battery cell.

[0099] In a second aspect, a battery device is provided, including the battery cell of the above embodiment.

[0100] For the battery device of the embodiment of the present application, by adopting the above battery cell, the use reliability of the battery cell is good, which is beneficial to improving the use reliability of the battery device.

[0101] In a third aspect, an electrical device is provided, including the battery device of the above embodiment.

[0102] For the battery device of the embodiment of the present application, by adopting the above battery cell, the use reliability of the battery device is good, which is beneficial to improving the use reliability of the electrical device.

[0103] The above description is only an overview of the technical solution of the present application. In order 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 given below. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] 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, other drawings can be obtained according to these drawings without creative efforts.

[0105] Figure 1 It is a schematic structural diagram of a vehicle provided by some embodiments of the present application.

[0106] Figure 2 It is an exploded view of a battery device provided by some embodiments of the present application.

[0107] Figure 3 It is an exploded view of a battery cell provided by some embodiments of the present application.

[0108] Figure 4 It is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application.

[0109] Figure 5 It is a sectional view taken along line A-A in Figure 4

[0110] Figure 6 It is a schematic structural diagram of a first electrode tab provided by some embodiments of the present application.

[0111] Figure 7 It is a sectional view taken along line B-B in Figure 6

[0112] Figure 8Schematic diagram of the first pole piece provided in some other embodiments of the present application.

[0113] Figure 9 For Figure 8 Partial enlarged view at position C in

[0114] Figure 10 Schematic diagram of the first pole piece with the conductive member hidden provided in some embodiments of the present application.

[0115] Figure 11 For Figure 10 Partial enlarged view at position D in

[0116] Figure 12 Schematic diagram of the first pole piece provided in some other embodiments of the present application.

[0117] Figure 13 For Figure 12 Partial enlarged view at position F in

[0118] Figure 14 For Figure 13 Schematic diagram of the first pole piece with the conductive member hidden shown in

[0119] Figure 15 For Figure 14 Partial enlarged view at position G in

[0120] Figure 16 Schematic diagram of the first pole piece provided in some other embodiments of the present application.

[0121] Figure 17 Along Figure 16 Cross-sectional view taken along line H-H in

[0122] Figure 18 Along Figure 16 Cross-sectional view taken along line I-I in

[0123] Figure 19 Schematic diagram of the first pole piece provided in some other embodiments of the present application.

[0124] Figure 20 For Figure 19 Partial enlarged view at position J in

[0125] Figure 21 Schematic diagram of the first pole piece provided in some other embodiments of the present application.

[0126] Figure 22 Along Figure 21 Cross-sectional view taken along line K-K in

[0127] Figure 23 Schematic diagram of the first insulating part provided in some embodiments of the present application.

[0128] Figure 24 A sectional view along the Figure 23 N-N line in the middle.

[0129] Among them, the reference numerals in the figure are as follows:

[0130] 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 connecting part; 311, first connecting sub-part; 312, second connecting sub-part; 32, second connecting part; 40, insulating part; 41, second insulating part; 42, first 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

[0131] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the following further describes the present application in detail with reference to the Figures 1 - 24 accompanying 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.

[0132] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0133] 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 construed as indicating or implying relative importance or implicitly specifying 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.

[0134] In the description of the embodiments of the present application, the term "and / or" is merely a description of the relationship between 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. Additionally, the character " / " in this text generally indicates an "or" relationship between the associated objects before and after.

[0135] In the description of the embodiments of the present application, the term "plural" 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 and clearly defined.

[0136] 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. This is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the embodiments of the present application.

[0137] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "coupling", "fixation", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may also 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 elements or the interaction relationship between two elements. 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.

[0138] In the description of the embodiments of the present application, unless otherwise clearly specified and 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.

[0139] 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 to continue to be used.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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 battery modules are accommodated in the box body.

[0145] 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.

[0146] In some embodiments, the battery device can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0147] The 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.

[0148] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode, which can prevent short - circuit between the positive and negative electrodes and allow active ions to pass through.

[0149] The outer shell is used to encapsulate components such as the electrode assembly and the electrolyte. The outer shell 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.

[0150] 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.

[0151] The current collector (positive electrode current collector or negative electrode current collector) is usually made of a metal material, such as aluminum metal foil and copper metal foil. However, pure metal foils are prone to generating metal burrs. The burrs penetrate the separator, resulting in an internal short - circuit, and there is a relatively high risk of fire and explosion in the battery cell.

[0152] In order to reduce the short - circuit risk in 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. 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 a foreign object piercing the electrode sheet, the burrs generated by the metal layer are small and not easily penetrate the separator. However, in the actual process of manufacturing the electrode sheet, the edge of the electrode sheet needs to be cut, so that the metal layer is divided into a protruding part and a main body part. The end face of the main body part facing the protruding part is obtained by cutting, and large burrs are easily generated at the cut end face, thus affecting the use reliability of the battery cell.

[0153] Based on this, the embodiments of the present application provide a technical solution. By setting an insulating member, and the first insulating part of the insulating member protrudes from the end of the main body part facing the protruding part, the first insulating part can block the burrs at the end face of the main body part facing the protruding part, reducing the risk of short - circuit caused by the burrs at this place piercing the separator, which is beneficial to improving the use reliability of the battery cell.

[0154] The battery cell described in the embodiments of the present application is applicable to battery devices and electrical devices using the battery devices.

[0155] The battery device disclosed in the embodiments of the present application can be used in electrical devices that use the battery device as a power source or various energy storage systems that use 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, a power tool, a battery car, an electric vehicle, a ship, a spacecraft, and the like. Among them, the electric toy can include a stationary 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.

[0156] For the convenience of description, the following embodiments will be described by taking the electrical device as a vehicle as an example.

[0157] As Figure 1 shown, a battery device 1100 is provided inside the vehicle 1000. The battery device 1100 can be provided at the bottom, head, or tail of the vehicle 1000. The battery device 1100 can be used to supply power to the vehicle 1000. For example, the battery device 1100 can be used as the operating power source of the vehicle 1000.

[0158] 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.

[0159] In some embodiments of the present application, the battery device 1100 can not only be used as the operating power source of the vehicle 1000, but also be used as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000. Figure 2 It is an exploded view of the battery device 1100 provided in some embodiments of the present application. As Figure 2 shown, the battery device 1100 includes a box body 300 and battery cells. The battery cells are accommodated in the box body 300.

[0160] The housing 300 is used to accommodate battery cells, and the housing 300 can have various structures. In some embodiments, the housing 300 can include a first housing portion 301 and a second housing portion 302. The first housing portion 301 and the second housing portion 302 are covered with each other, and the first housing portion 301 and the second housing portion 302 jointly define an accommodation space for accommodating battery cells. The second housing portion 302 can be a hollow structure with an open end, and the first housing portion 301 is a plate-like structure. The first housing portion 301 covers the open side of the second housing portion 302 to form the housing 300 with an accommodation space; both the first housing portion 301 and the second housing portion 302 can also be hollow structures with an open side, and the open side of the first housing portion 301 covers the open side of the second housing portion 302 to form the housing 300 with an accommodation space. Of course, the first housing portion 301 and the second housing portion 302 can have various shapes, such as a cylinder, a cuboid, etc.

[0161] To improve the sealing performance after the connection between the first housing portion 301 and the second housing portion 302, a sealing member, such as sealant, sealing ring, etc., can also be provided between the first housing portion 301 and the second housing portion 302.

[0162] Assume that the first housing portion 301 covers the top of the second housing portion 302. The first housing portion 301 can also be called the upper cover, and the second housing portion 302 can also be called the lower housing 300.

[0163] In the battery device 1100, there can be one or multiple battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells.

[0164] The multiple battery cells can be directly connected in series, parallel, or in a mixed connection together, and then the whole formed by the multiple battery cells is accommodated in the housing 300; of course, it can also be that multiple battery cells are first connected in series, parallel, or in a mixed connection to form battery modules, and then the multiple battery modules are connected in series, parallel, or in a mixed connection to form a whole and are accommodated in the housing 300.

[0165] Exemplarily, the battery cell can be the smallest unit constituting the battery device 1100.

[0166] As Figure 3 shown, in some embodiments, the battery cell includes a housing 200 and an electrode assembly 101 accommodated in the housing 200. The electrode assembly 101 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. 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 can also allow active ions to pass through.

[0167] The outer shell 200 is used to encapsulate components such as the electrode assembly 101 and the electrolyte.

[0168] In some embodiments, the outer shell 200 includes a housing 202 and an end cap 201. The housing 202 has an opening, and the end cap 201 is used to cover the opening.

[0169] The housing 202 is a component used to cooperate with the end cap 201 to form the internal cavity of the battery cell. The formed internal cavity can be used to accommodate the electrode assembly 101, the electrolyte, and other components.

[0170] The housing 202 and the end cap 201 can be independent components. Exemplarily, an opening can be provided on the housing 202, and the end cap 201 is covered at the opening to form the internal cavity of the battery cell.

[0171] The housing 202 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 202 can be determined according to the specific shape and size of the electrode assembly 101. The material of the housing 202 can be various. For example, the material of the housing 202 includes but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum plastic film, steel plastic film, etc.

[0172] The shape of the end cap 201 can be adapted to the shape of the housing 202 to cooperate with the housing 202. The material of the end cap 201 can be the same as or different from the material of the housing 202. Optionally, the end cap 201 can be made of a material with 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 to have higher structural strength and improved reliability.

[0173] The end cap 201 is connected to the housing 202 by welding, bonding, clamping, or other means.

[0174] The housing 202 can have an opening at one end or two 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.

[0175] In some embodiments, the battery cell includes electrode lead-out parts 2011. The number of the electrode lead-out parts 2011 is two, and the two electrode lead-out parts 2011 are respectively connected to the positive electrode plate and the negative electrode plate to output or input the electric energy of the battery cell.

[0176] In some embodiments, the battery cell further includes an electrolyte accommodated in the housing 200. The electrolyte functions to conduct ions between the positive and negative electrodes. The electrolyte can be liquid, gel - state, or solid - state.

[0177] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0178] 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 difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro - bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0179] 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.

[0180] The solvent may also be an ether - type solvent. The ether - type solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3 - dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0181] In some embodiments, the gel - state electrolyte includes a polymer as the skeletal network of the electrolyte, combined with an ionic liquid - lithium salt.

[0182] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0183] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single - ion polymer, poly(ionic liquid) - lithium salt, cellulose, etc.

[0184] As an example, the inorganic solid electrolyte may 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.

[0185] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0186] Referring to Figure 4 and Figure 5 In the embodiment of the present application, the electrode assembly 101 includes a first electrode tab 1 and a second electrode tab 2 with opposite polarities.

[0187] Exemplarily, one of the first electrode tab 1 and the second electrode tab 2 is a positive electrode tab, and the other is a negative electrode tab.

[0188] In some embodiments, the positive electrode tab 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.

[0189] 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.

[0190] 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 substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0191] As an example, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds. The positive electrode active material can also use other conventional materials that can be used as the positive electrode active material layer of the battery device 1100. These positive electrode active materials can be used alone or in combination of two or more. Examples of lithium-containing phosphate may include, but are not limited to, lithium iron phosphate (such as LiFePO4 (which can 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, a composite material of lithium manganese iron phosphate and carbon, etc. Examples of 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 can also be abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3O2 (which can also be abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0192] 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.

[0193] 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, a carbon electrode, nickel, or titanium, etc. can be used. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. 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 copper, copper 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.).

[0194] 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 use in a battery cell. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials may include at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials may 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.

[0195] 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.

[0196] In some embodiments, the electrode assembly 101 further includes a separator 3, which 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 allow active ions to pass through.

[0197] In some embodiments, the separator 3 includes a separator membrane. The separator membrane of the present application can be any well-known porous structure separator membrane with good chemical stability and mechanical stability.

[0198] As an example, the main materials of the separator membrane may 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 attached to the surfaces of the positive and negative electrodes.

[0199] 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 simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0200] In some embodiments, the electrode assembly 101 has a wound structure. Exemplarily, both the first electrode sheet 1 and the second electrode sheet 2 are strip-shaped structures, and the first electrode sheet 1, the separator 3, and the second electrode sheet 2 are wound into a wound structure.

[0201] In some embodiments, the electrode assembly 101 has a stacked structure.

[0202] As an example, multiple first electrode sheets 1 and multiple second electrode sheets 2 can be respectively provided, and the multiple first electrode sheets 1 and the multiple second electrode sheets 2 are alternately stacked.

[0203] As an example, multiple first electrode sheets 1 can be provided, and the second electrode sheet 2 is folded to form multiple stacked folding segments, and a first electrode sheet 1 is clamped between adjacent folding segments.

[0204] As an example, both the first electrode sheet 1 and the second electrode sheet 2 are folded to form multiple stacked folding segments.

[0205] As an example, multiple separators 3 can be provided and respectively disposed between any adjacent first electrode sheets 1 or second electrode sheets 2.

[0206] As an example, the separator 3 can be continuously provided and disposed between any adjacent first electrode sheets 1 or second electrode sheets 2 by folding or winding.

[0207] In some embodiments, the shape of the electrode assembly 101 can be cylindrical, flat, prismatic, etc.

[0208] Please refer to Figure 6 andFigure 7 As shown, in some embodiments, a battery cell is provided. The battery cell 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 an insulating member 40. The first electrode tab 1 includes a conductive member 30, a current collector 10, and an active material layer 20. The current collector 10 includes an insulating substrate 11 and a metal layer 12. The conductive member 30 connects the electrode lead-out portion 2011 and the metal layer 12. The insulating substrate 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 substrate 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. The first direction is perpendicular to the thickness direction of the current collector 10. At least a part of the main body portion 121 is covered with the active material layer 20. At least a part of the protruding portion 122 is not covered with the active material layer 20. The insulating member 40 includes a first insulating portion 42. The first insulating portion 42 is located on a side of the main body portion 121 facing away from the insulating substrate 11. Along the direction from the main body portion 121 to the protruding portion 122, the first insulating portion 42 protrudes from an end of the main body portion 121 facing the protruding portion 122.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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 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.

[0213] The electrode lead-out part 2011 is connected to the conductive member 30, and 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; alternatively, the electrode lead-out part 2011 can be connected to the conductive member 30 through a conductive part (such as a transfer piece, etc.). For example, one end of the conductive part is welded to the conductive member 30, and the other end of the conductive part is welded to the electrode lead-out part 2011.

[0214] 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 substrate 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.

[0215] 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.

[0216] In some examples, one surface of the insulating substrate 11 is covered with a metal layer 12.

[0217] 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 covered on the surface facing away from the insulating body.

[0218] 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.

[0219] 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 ).

[0220] 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

[0221] The metal layer 12 includes a main body portion 121 and a protruding portion 122. The main body portion 121 is the main body portion of the metal layer 12; the protruding portion 122 extends outward from the end of the main body portion 121 in the first direction. The protruding portion 122 can be a protruding structure formed on the side edge of the main body portion 121 in the first direction. Among them, along the second direction, the size of the protruding portion 122 is smaller than that 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. 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

[0222] 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.

[0223] The insulating member 40 can refer to a component that can insulate. The insulating member 40 can refer to an integrated structure or can also be multiple parts that are separately formed and then assembled together; the insulating member 40 includes a first insulating portion 42, and the first insulating portion 42 can be but is not limited to an insulating coating, insulating glue (such as hot melt glue, etc.) or insulating tape.

[0224] The first insulating portion 42 is located on the side portion of the first pole piece 1 in the thickness direction, and the first insulating portion 42 at least partially covers the junction of the main body portion 121 and the protruding portion 122; exemplarily, along the thickness direction of the current collector 10, the projection of the end face of the main body portion 121 facing the protruding portion 122 coincides with the projection of the first insulating portion 42, so that the first insulating portion 42 can cover the end face where the main body portion 121 leads out the protruding portion 122.

[0225] For the battery cell according to the embodiment of the present application, when the battery cell 100 is in normal use, the electrode lead-out portion 2011 is used for inputting or outputting electric energy, realizing the charging and discharging of the battery cell 100; the first insulating portion 42 can prevent the burrs at the end face of the main body portion 121 facing the protruding portion 122 from piercing through the separator 3 and contacting the second electrode sheet 2, thereby reducing the short-circuit risk of the battery cell and being beneficial to improving the use reliability of the battery cell; in addition, the current collector 10 adopts a composite structure of an insulating substrate 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 internal short-circuit risk of the battery cell and being beneficial to improving the use reliability of the battery cell; therefore, the battery cell according to the embodiment of the present application can better balance the over-current capacity and the use reliability.

[0226] In some embodiments, the active material layer 20 includes a first active material portion 21 and a second active material portion 22. The end of the first active material portion 21 facing the protruding portion 122 is connected to the end of the second active material portion 22, and the thickness of the first active material portion 21 is less than the thickness of the second active material portion 22.

[0227] In some examples, the first active material portion 21 is located at the edge of the active material layer 20 facing the protruding 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 can be generally of an equal-thickness structure, and the thickness of the first active material portion 21 is less than the thickness of the second active material portion 22, so 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 can also decrease step by step, so that the first active material portion 21 is a stepped structure; or, along the direction of the main body portion 121 facing the protruding portion 122, the thickness of the first active material portion 21 can also decrease slowly, so 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.

[0228] During the forming process of the first electrode sheet 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 received by the edge of the active material layer 20 and reduce the risk of cracking at the edge of the active material layer 20.

[0229] Please refer to Figures 8 - 14As shown, 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. The second connection portion 32 is located on the side of the protruding portion 122 facing away from the main body portion 121. Along the first direction, the first welding mark 51 is located on the side of the active material layer 20 close to the protruding portion 122.

[0230] 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.

[0231] In some examples, the first connection portion 31 may cover the metal layer 12 and be welded to the metal layer 12. The second connection portion 32 may extend out along the first direction from the side of the first connection portion 31 facing away from the active material layer 20 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 the connection reliability.

[0232] In some cases, when the electrode sheet is wound to form the electrode assembly 101, the insulating substrate 11 insulates the adjacent two layers of the metal layer 12, making it difficult for the adjacent two layers of the metal layer 12 to be directly connected across the insulating substrate 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, affecting the use reliability of the battery cell 100. However, for the battery cell 100 in the embodiment of the present application, the first connection portion 31 of the conductive member 30 is welded to the metal layer 12, and the second connection portion 32 of the conductive member 30 protrudes outside the insulating substrate 11. In this way, the adjacent two layers of the metal layer 12 can be electrically conducted through the second connection portion 32, thereby breaking the insulation limitation of the insulating substrate 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.

[0233] When forming the electrode assembly 101 by stacking the electrode tabs, the insulating substrate 11 insulates and separates two adjacent metal layers 12 from each other, 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 by the outermost metal layer 12, resulting in poor conductivity, low fast-charging performance, and easy local overheating, which affects the reliability of the battery cell 100. However, for 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 substrate 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 substrate 11, effectively improving the conductivity of the first electrode tab 1, enhancing the fast-charging performance of the battery cell 100, reducing the heat generation of the battery cell, and improving the reliability of the battery cell 100.

[0234] The first connecting portion 31 is stacked on the surface of the metal layer 12 facing away from the insulating substrate 11 and welded to the surface of the metal layer 12 facing away from the insulating substrate 11. The trace formed by the welding is the first welding mark 51.

[0235] "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 spaced from the active material layer 20, so that the part of the metal layer 12 facing the protruding portion 122 that is not covered by the active material layer 20 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 over-current capacity of 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.

[0236] In some examples, the first connecting portion 31 may be welded only to the protruding portion 122.

[0237] 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 that is not covered by the active material layer 20.

[0238] In some examples, the second connecting portion 32 and the electrode lead-out portion 2011 can be connected by direct welding, or can also be welded through a conductive member (such as a transfer piece, etc.). The welding method is convenient for connection operation and processing. Of course, the connection can also be achieved by other means.

[0239] By adopting the technical solution of this embodiment, the first connection part 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 manufacture of the first pole piece 1. In addition, the metal layer 12 has a small thickness and a large surface facing away from the insulating substrate 11, 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, beneficial to improving the current-carrying capacity of the first pole piece 1, and improving the fast charging performance of the battery device 1100 single cell. The second connection part 32 protrudes outside the main body part 121, which facilitates the connection between the second connection part 32 and the electrode lead-out part 2011, and the processing and manufacture are more convenient. At the same time, it can also reduce the risk of problems such as false soldering, 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 pole piece 1 and the fast charging performance of the battery device 1100 single cell.

[0240] In some embodiments, the first insulating part 42 covers at least part of the first welding mark 51.

[0241] The first insulating part 42 covers the surface of the first connection part 31 facing away from the metal layer 12 and covers at least part of the first welding mark 51. Among them, the first insulating part 42 can cover a part of the first welding mark 51 or can cover the entire first welding mark 51.

[0242] After the first connection part 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 welding mark 51. However, the first insulating part 42 of the embodiment of the present application covers the surface of the first welding mark 51, which can prevent components such as burrs and metal debris on the surface of the first welding mark 51 from piercing through the separator 3 and connecting to the second pole piece 2, reducing the short-circuit risk of the battery single cell and improving the use reliability of the battery single cell.

[0243] In some embodiments, along the first direction, the first connection part 31 and the active material layer 20 are arranged at intervals.

[0244] The first connection part 31 and the active material layer 20 do not directly contact each other, but there is a certain gap, so that the first connection part 31 does not contact the active material layer 20.

[0245] In some examples, the first pole piece 1 is a positive electrode piece, and the first connection part 31 does not contact the active material layer 20, which can reduce risks such as lithium deposition and is beneficial to improving the use reliability of the battery single cell. In other examples, the first pole piece 1 is a negative electrode piece, and the first connection part 31 can contact the active material layer 20 or can not contact it.

[0246] By adopting the technical solution of this embodiment, the first connection part 31 does not contact the active material layer 20, which can reduce the mutual influence between the two and improve the use reliability of the battery single cell.

[0247] Please refer to Figures 15 - 17 As shown, in some embodiments, the insulating member 40 includes a second insulating portion 41 that covers the surface of the metal layer 12 facing away from the insulating substrate 11, and the entire second insulating portion 41 is located between the first solder mark 51 and the active material layer 20.

[0248] The second insulating portion 41 may refer to an insulating component that covers the surface of the metal layer 12 facing away from the active material layer 20; the second insulating portion 41 may be, but is not limited to, an insulating coating, an insulating adhesive (e.g., a hot melt adhesive, etc.), or an insulating tape.

[0249] In the thickness direction of the current collector 10, the second insulating portion 41 does not overlap with the first solder mark 51, and the second insulating portion 41 is spaced from the first solder mark 51, such that the first connecting portion 31 will not be welded to the second insulating portion 41, which is beneficial to reducing the risk of poor soldering between the first connecting portion 31 and the metal layer 12; alternatively, the second insulating portion 41 and the first solder mark 51 only overlap at the edges, and the edges of the first solder mark 51 coincide with the edges of the second insulating portion 41, which can also reduce the risk of poor soldering between the first connecting portion 31 and the metal layer 12.

[0250] By adopting the technical solution of this embodiment, it is beneficial to reduce the risk of poor 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 is also beneficial to improving the current-carrying capacity.

[0251] In some embodiments, the second insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0252] The second insulating portion 41 may refer to the part of the second insulating portion 41 located between the first connecting portion 31 and the active material layer 20.

[0253] In some examples, the entire second insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0254] By adopting the technical solution of this embodiment, the second 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 damages such as cracks and fractures that occur in this part during the manufacturing process of the battery device 1100, is beneficial to improving the electron transmission ability of this part, and improving the fast charging performance and use reliability of the single battery device 1100; in addition, the first insulating portion 42 can also insulate this part, reduce the short-circuit risk of the single battery device 1100, and improve the use reliability of the single battery device 1100.

[0255] In some embodiments, along the first direction, one side of the first insulating portion 42 covers the first solder pad 51, and the other side of the first insulating portion 42 covers at least a part of the second insulating portion 41.

[0256] It can be understood that, among the opposite two sides of the first insulating portion 42 along the first direction, one side covers the first solder pad 51, and the other side can cover the entire second insulating portion 41, or can cover a part of the second insulating portion 41, or even cover the active material layer 20.

[0257] Along the first direction, the first insulating portion 42 extends from the first solder pad 51 to the second insulating portion 41; or, the first insulating portion 42 extends from the first solder pad 51 to the active material layer 20, so as to completely cover the second insulating portion 41.

[0258] By adopting the technical solution of this embodiment, in addition to covering at least a part of the first solder pad 51 and the second insulating portion 41, the first insulating portion 42 can also cover the part of the first connecting portion 31 located between the second insulating portion 41 and the first solder pad 51. The coverage of the insulating member 40 is more comprehensive, which is more beneficial to reducing the short - circuit risk and improving the use reliability of the battery cell.

[0259] Please refer to Figures 18 - 21 As shown, in some embodiments, along the first direction, one side of the first insulating portion 42 covers the first solder pad 51, and the other side of the first insulating portion 42 covers at least a part of the active material layer 20.

[0260] It can be understood that, among the two sides of the first insulating portion 42 that are oppositely distributed along the first direction, one side covers the first solder pad 51, and the other side covers at least a part of the active material layer 20. Among them, the first insulating portion 42 can cover the end of the active material layer 20 facing the first connecting portion 31, or can cover the entire active material layer 20.

[0261] Along the first direction, the first insulating portion 42 extends from the first solder pad 51 to the active material layer 20, so as to cover the part of the metal layer 12 and the first connecting portion 31 located between the first solder pad 51 and the active material layer 20. Among them, a second insulating portion 41 can be provided between the first insulating portion 42 and the metal layer 12, or the second insulating portion 41 can not be provided.

[0262] In some examples, the metal layer 12 is covered with the second insulating portion 41. After the first insulating portion 42 completely covers the second insulating portion 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 second insulating portion 41 and the first insulating portion 42, realizing two - layer insulation with good insulation effect.

[0263] In some examples, the metal layer 12 is not covered with the second insulating portion 41, and the first insulating portion 42 extends from the first solder pad 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 service reliability of the battery cell. In addition, the second 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 second insulating portion 41, which can increase 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.

[0264] By adopting the technical solution of this embodiment, the first insulating portion 42 extends onto the active material layer 20 from the first solder pad 51. The first insulating portion 42 has a wide coverage area and good insulation effect, which is beneficial to improving the service reliability of the battery cell.

[0265] In some embodiments, along the first direction, the size 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.

[0266] 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.

[0267] The design of 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 service reliability of the battery cell. The design of 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.

[0268] In some examples, the insulating member 40 includes a second insulating portion 41. The second insulating portion 41 covers the end portion of the active material layer 20 facing the protruding portion 122. The portion of the second insulating portion 41 covering the active material layer 20 may refer to the mutually soluble region formed by the second insulating portion 41 and the active material layer 20, so that the fixing of the second insulating portion 41 is more stable.

[0269] In some examples, the insulating member 40 includes a first insulating portion 42. The first insulating portion 42 covers the end portion of the active material layer 20 facing the protruding portion 122.

[0270] By adopting the technical solution of this embodiment, along the first direction, the size of the part of the first 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 problem of the battery cell.

[0271] In some embodiments, 0.3 mm ≤ H ≤ 0.8 mm.

[0272] By adopting the technical solution of this embodiment, along the first direction, the size of the part of the first insulating portion 42 covering the active material layer 20 is more reasonable, and it can better take into account both 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.

[0273] Please refer to Figures 6 - 11 As shown, in some embodiments, the first welding mark 51 includes a first welding mark portion 511. The first connecting portion 31 is welded to the surface of the protruding portion 122 facing away from the insulating base 11 to form the first welding mark portion 511, and the first insulating portion 42 covers at least part of the first welding mark portion 511.

[0274] The first connecting portion 31 is stacked on the surface of the protruding portion 122 facing away from the insulating base 11 and welded to the protruding portion 122, and the trace formed by the welding is the first welding mark portion 511.

[0275] 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.

[0276] The first insulating portion 42 can cover a part of the first welding mark portion 511, or can cover the entire first welding mark portion 511.

[0277] By adopting the technical solution of this embodiment, the first connecting portion 31 and the protruding portion 122 are connected by welding, and the connection method is simple, which is convenient for the production of the first pole piece 1; 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; the first insulating portion 42 can prevent burrs, metal debris and other components on the first welding mark portion 511 from passing through the separator 3 and connecting with the second pole piece 2, which is beneficial to improving the use reliability of the battery cell.

[0278] 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.

[0279] Along the first direction, the projection of the first welding mark portion 511 falls within the projection of the protruding portion 122.

[0280] During the manufacturing process of the first electrode tab 1, the conductive member 30 can be welded to the edge of the equal-length current collector 10 by ultrasonic welding (e.g., double-roll continuous ultrasonic welding) or other welding methods to form an equal-width weld mark, and then the conductive member 30 is cut by laser die-cutting or other cutting methods to form a tab for facilitating connection with the electrode lead-out portion 2011. During the cutting process, first, a cut is made in the second direction between the equal-width weld mark and the active material layer 20, and then a cut is made toward the equal-width weld mark until after leaving the equal-width weld mark. After continuing to cut a certain distance away from the active material layer 20, a cut is made in the second direction for a certain distance, and then a cut is made in the direction toward the equal-width weld mark until after leaving the equal-width weld mark, and then a cut is made in the second direction, thus obtaining a first weld mark portion 511. By repeating this cycle, multiple first weld mark portions 511 are obtained.

[0281] By adopting the technical solution of this embodiment, along the second direction, the dimension of the first weld mark portion 511 in the second direction is large, which is beneficial to increasing the current-carrying area between the first connection portion 31 and the protruding portion 122, beneficial to improving the current-carrying capacity between the first connection portion 31 and the protruding portion 122, beneficial to reducing the risk of heat generation, and beneficial to improving the fast charging performance and service reliability of the battery cell.

[0282] In some embodiments, the first weld mark portion 511 includes a first weld mark sub-portion 5111, the protruding portion 122 includes a first protruding sub-portion 1221 and a second protruding sub-portion 1222, and 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 l1 of the first protruding sub-portion 1221 is greater than the dimension l2 of the second protruding sub-portion 1222. The second direction is perpendicular to the first direction and the thickness direction of the current collector 10. The first connection portion 31 is welded to the surface of the first protruding sub-portion 1221 facing away from the insulating matrix 11 to form the first weld mark sub-portion 5111, and the first insulating portion 42 covers at least a part of the first weld mark sub-portion 5111.

[0283] 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 of the first protruding sub-portion 1221 is greater than the dimension of the second protruding sub-portion 1222, which is equivalent to increasing the dimension of the first protruding sub-portion 1221 in 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.

[0284] The first protruding sub - part 1221 may refer to the root of the protruding part 122 close to the main body part 121; by way of example, along the second direction, the dimension l1 of the first protruding sub - part 1221 may refer to the length of the demarcation line (see the dotted line Q) between the protruding part 122 and the main body part 121. The dimension l1 of each first protruding sub - part 1221 along the second direction may be the same or different.

[0285] Along the second direction, the dimension l2 of the second protruding sub - part 1222 is equal to the length of the demarcation line (see the dotted line M) between the first protruding sub - part 1221 and the second protruding sub - part 1222. The dimension l2 of each second protruding sub - part 1222 along the second direction may be the same or different.

[0286] l1>l2, which is equivalent to increasing the dimension l1 of the first protruding sub - part 1221 along the second direction, increasing the current - passing area between the protruding part 122 and the main body part 121, improving the current - passing capacity, and reducing the heat generation of the battery cell 100.

[0287] The first connecting part 31 is welded to the surface of the first protruding sub - part 1221 facing away from the insulating substrate 11, and the trace generated by the welding is the first welding mark sub - part 5111.

[0288] By way of example, the first connecting part 31 can be welded to the side of the first protruding sub - part 1221 facing the main body part 121, so that the first welding mark sub - part 5111 is directly connected to the main body part 121; in this way, the first connecting part 31 and the main body part 121 can directly pass current through the first welding mark part 511, which is beneficial to improving the current - passing capacity between the first connecting part 31 and the main body part 121, reducing the heat generation of the battery cell 100, and improving the fast - charging performance and use reliability of the battery cell; of course, the first connecting part 31 can also be welded to the side of the first protruding sub - part 1221 facing away from the main body part 121, so that the first welding mark sub - part 5111 is spaced from the main body part 121.

[0289] The first insulating part 42 can cover a part of the first welding mark sub - part 5111 or can cover the entire first welding mark sub - part 5111.

[0290] 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 welded mark sub-portion 5111. The dimension 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. In addition, along 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. In addition, the first insulating portion 42 can prevent components such as burrs and metal debris on the first welded mark sub-portion 5111 from passing through the separator 3 and connecting to the second pole piece 2, which is beneficial to improving the service reliability of the battery cell.

[0291] In some embodiments, along the second direction, the sum l3 of the dimensions of the first protruding sub-portions 1221 of all the protruding portions 122 is more than 0.5 times the dimension l4 of the main body portion 121. It can be understood that 0.5 ≤ l3 / l4 < 1, so that along the second direction, the sum l3 of the dimensions of the first protruding sub-portions 1221 of all the protruding portions 122 is greater than or equal to half of the dimension l4 of the main body portion 121, increasing the total current-carrying area between the protruding portion 122 and the main body portion 121 and improving the total current-carrying capacity between the protruding portion 122 and the main body portion 121. Exemplarily, the sum l3 of the dimensions of the first protruding sub-portions 1221 of all the protruding portions 122 in the second direction can be increased by increasing the number of the protruding portions 122, or the sum l1 of the dimensions of the first protruding sub-portions 1221 of all the protruding portions 122 in the second direction can be increased by increasing the dimension l4 of a single first protruding sub-portion 1221 in the second direction.

[0292] In some examples, the value of l3 / l4 can be 0.5 and any value between 0.5 and 1. Exemplarily, among them, the value of l3 / l4 can be, but is not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99.

[0293] In some embodiments, along the direction from the main body portion 121 to the protruding portion 122, the first insulating portion 42 protrudes from the end face of the first protruding sub-portion 1221 facing away from the main body portion 121.

[0294] In 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 first insulating portion 42.

[0295] During the production process of the electrode tab, the end face of the first protruding sub - portion 1221 facing away from the main body portion 121 is obtained by cutting, which makes it easy for burrs to be generated on the end face of the first protruding sub - portion 1221 facing away from the main body portion 121. The first 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 risk of short - circuit inside the battery cell and being beneficial to improving the use reliability of the battery cell. Additionally, the first insulating portion 42 can completely cover the first welding imprint sub - portion 5111, reducing the risk of short - circuit caused by burrs, metal debris and other components on the first welding imprint sub - portion 5111, which is beneficial to improving the use reliability of the battery cell.

[0296] In some embodiments, along the second direction, the first welding imprint 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.

[0297] Along the first direction, the projection of the first welding imprint sub - portion 5111 falls within the projection of the first protruding sub - portion 1221.

[0298] By adopting the technical solution of this embodiment, the first welding imprint sub - portion 5111 has a large size along the second direction, 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 use reliability of the battery cell.

[0299] In some embodiments, the first welding imprint portion 511 further includes a second welding imprint 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 substrate 11 to form the second welding imprint sub - portion 5112, and the first insulating portion 42 covers at least a part of the second welding imprint sub - portion 5112.

[0300] Exemplarily, the surface of the second protruding sub - portion 1222 facing away from the insulating substrate 11 is welded to the first connecting portion 31, and the trace generated by the welding is the second welding imprint sub - portion 5112.

[0301] The first insulating portion 42 can cover a part of the second welding imprint sub - portion 5112 or can cover the entire second welding imprint sub - portion 5112.

[0302] 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. Additionally, the first insulating portion 42 can block burrs, metal debris and other components on the second welding imprint sub - portion 5112 from passing through the separator 3 and connecting to the second electrode tab 2, which is beneficial to improving the use reliability of the battery cell.

[0303] In some embodiments, along the direction from the main body portion 121 towards the protruding portion 122, the first insulating portion 42 protrudes beyond the edge of the second welding imprint sub-portion 5112 facing away from the first protruding sub-portion 1221.

[0304] In the thickness direction of the current collector 10, the projection of the edge of the second welding imprint sub-portion 5112 facing away from the first protruding sub-portion 1221 falls within the projection of the first insulating portion 42, such that the first insulating portion 42 can completely cover the second welding imprint sub-portion 5112 and the first welding imprint sub-portion 5111.

[0305] By adopting the technical solution of this embodiment, the first 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.

[0306] In some embodiments, along the second direction, the second welding imprint 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.

[0307] Along the first direction, the projection of the second welding imprint sub-portion 5112 falls within the projection of the second protruding sub-portion 1222. The second welding imprint sub-portion 5112.

[0308] By adopting the technical solution of this embodiment, the dimension of the second welding imprint sub-portion 5112 along the second direction is large, which is beneficial to increasing the welding area between the first connecting portion 31 and the protruding portion 122, 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.

[0309] Please refer to Figures 12 - 22 As shown, in some embodiments, the main body portion 121 includes a conductive portion 1212 and a transition portion 1211. The transition portion 1211 is connected between the conductive portion 1212 and the protruding portion 122. The transition portion 1211 and the protruding portion 122 are not covered with the active material layer 20, and the conductive portion 1212 is covered with the active material layer 20; the first insulating portion 42 covers at least a part of the surface of the transition portion 1211 facing away from the insulating substrate 11; along the direction from the main body portion 121 towards the protruding portion 122, the first insulating portion 42 protrudes beyond the end of the transition portion 1211 facing away from the conductive portion 1212.

[0310] Exemplarily, along the first direction, the main body portion 121 is divided into two parts. Among them, the part close to the protruding portion 122 is the transition portion 1211, and the part far from the protruding portion 122 is the conductive portion 1212. The protruding portion 122 protrudes away from the conductive portion 1212 from the edge of the transition portion 1211 that is far from the conductive portion 1212; the conductive portion 1212 is covered with an active material layer 20, and neither the transition portion 1211 nor the protruding portion 122 is covered with the active material layer 20 to facilitate connection with the first connection portion 31.

[0311] In some examples, the first connection portion 31 is connected to the surface of the transition portion 1211 facing away from the insulating substrate 11 by means of welding or conductive adhesive, etc., to realize the connection between the first connection portion 31 and the transition portion 1211.

[0312] By adopting the technical solution of this embodiment, the surface of the transition portion 1211 in the main body portion 121 facing away from the insulating substrate 11 is connected to the first connection portion 31, so that a part of the current can flow directly into or out of the first connection portion 31 through the transition portion 1211, reducing the overcurrent pressure between the protruding portion 122 and the main body portion 121, which is beneficial to reducing the heat generation at the first protruding sub-portion 1221 and is beneficial to improving the fast charging performance and use reliability of the battery cell.

[0313] In some embodiments, along the second direction, the size of the conductive portion 1212 is L1, and the size of the transition portion 1211 is L2, where 0.8 ≤ L2 / L1 ≤ 1. Here, the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0314] 0.8 ≤ L2 / L1 ≤ 1. Along the second direction, the size L2 of the transition portion 1211 is less than or equal to the size L1 of the conductive portion 1212, and the size L2 of the transition portion 1211 is greater than or equal to 0.8 times the size L1 of the conductive portion 1212. The size L2 of the transition portion 1211 exceeds more than half of the size L1 of the conductive portion 1212. The larger the size 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 overcurrent capacity between the transition portion 1211 and the first connection portion 31.

[0315] 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.

[0316] In some examples, 0.8 ≤ L2 / L1 < 1. Along the second direction, the transition part 1211 may also be disposed towards one end of the conductive part 1212, such that one end of the transition part 1211 is flush with the conductive part 1212, and the other end is not flush, or neither end is flush. The value of L2 / L1 may be, but is not limited to, 0.8, 1, or any value between 0.8 and 1. Exemplarily, the value of L2 / L1 may be, but is not limited to, 0.8, 0.85, 0.9, 0.95, 1.

[0317] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L2 / L1 ≤ 1 makes the size of the transition part 1211 along the second direction large, which is beneficial to increasing the connection area between the first connection part 31 and the transition part 1211, improving the current-carrying capacity at the connection between the first connection part 31 and the transition part 1211, enhancing 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 of the battery cell.

[0318] In some embodiments, L2 = L1.

[0319] L2 / L1 = 1. Along the second direction, the size L2 of the transition part 1211 is equal to the size L1 of the conductive part 1212. In the second direction, both ends of the transition part 1211 are flush with the conductive part 1212, and the main body part 121 has an equal-length structure.

[0320] By adopting the technical solution of this embodiment, the design of L2 = L1 makes the size of the transition part 1211 along the second direction relatively large, which is beneficial to designing a relatively large connection area between the first connection part 31 and the transition part 1211. The current-carrying capacity at the connection between the first connection part 31 and the transition part 1211 is the best, which can effectively improve the current-carrying capacity of the first pole piece 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell.

[0321] In some embodiments, the first welding mark 51 further includes a second welding mark part 512. The first connection part 31 is welded to the surface of the transition part 1211 facing away from the insulating base 11 to form the second welding mark part 512, and the first insulating part 42 covers at least a part of the second welding mark part 512.

[0322] The first connection part 31 is welded to the surface of the transition part 1211 facing away from the insulating base 11, and the trace generated by the welding of the transition part 1211 and the first connection part 31 is the second welding mark part 512.

[0323] In some examples, the first welding mark 51 only includes the second welding mark part 512, that is, the first connection part 31 is only welded to the transition part 1211.

[0324] In some examples, the first welding mark 51 includes a second welding mark portion 512 and a first welding mark portion 511. The first welding mark portion 511 is located between the second welding mark portion 512 and the active material layer 20, that is, the first connecting portion 31 is welded to the transition portion 1211 and the protruding portion 122 simultaneously.

[0325] The first insulating portion 42 may cover a part of the second welding mark portion 512 or may cover the entire first insulating portion 42.

[0326] 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 tab 1. In addition, the second welding 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. In addition, the first insulating portion 42 can prevent burrs, metal debris and other components on the second welding mark portion 512 from passing through the separator 3 and connecting to the second electrode tab 2, which is beneficial to improving the reliability of the battery cell in use.

[0327] In some embodiments, along the direction from the protruding portion 122 to the main body portion 121, the first insulating portion 42 protrudes from the edge of the second welding mark portion 512 facing the active material layer 20.

[0328] Along the thickness direction of the current collector 10, the projection of the edge of the second welding mark portion 512 facing away from the active material layer 20 falls within the projection of the first insulating portion 42, so that the first insulating portion 42 can completely cover the second welding mark portion 512.

[0329] By adopting the technical solution of this embodiment, the first insulating portion 42 can completely cover the second welding mark portion 512, and the first insulating portion 42 can prevent burrs, metal debris and other components on the entire second welding mark portion 512 from passing through the separator 3 and connecting to the second electrode tab 2, which is beneficial to improving the reliability of the battery cell in use.

[0330] In some embodiments, along the second direction, the size of the transition portion 1211 is L2, and the size of the second welding mark portion 512 is L3, where 0.8 ≤ L3 / L2 ≤ 1, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0331] 0.8 ≤ L3 / L2 ≤ 1. Along the second direction, the dimension L3 of the second welding imprint portion 512 can be less than or equal to the dimension L2 of the transition portion 1211. The dimension L3 of the second welding imprint portion 512 is greater than or equal to 0.8 times the dimension L2 of the transition portion 1211. The dimension L3 of the second welding imprint portion 512 exceeds half of the dimension L2 of the transition portion 1211. The longer the dimension L3 of the second welding imprint portion 512, the larger the welding area between the transition portion 1211 and the first connecting portion 31, and the better the current-carrying capacity at the connection between the transition portion 1211 and the first connecting portion 31.

[0332] In some examples, 0.8 ≤ L3 / L2 < 1. Along the second direction, the second welding imprint portion 512 can be located at the middle position of the transition portion 1211, and both ends of the second welding imprint portion 512 are not flush with the transition portion 1211.

[0333] In some examples, 0.8 ≤ L2 / L1 < 1. Along the second direction, the second welding imprint portion 512 can also be disposed to bias 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.

[0334] 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.

[0335] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L3 / L2 ≤ 1 makes the dimension of the transition portion 1211 along the second direction larger, which is conducive to increasing the connection area between the first connecting portion 31 and the transition portion 1211, improving the current-carrying capacity at the connection between the first connecting 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 100, and improving the fast charging performance of the battery cell.

[0336] In some embodiments, L3 = L2.

[0337] L3 / L2 = 1. Along the second direction, the dimension L3 of the second welding imprint portion 512 is equal to the dimension L2 of the transition portion 1211, and both ends of the second welding imprint portion 512 are flush with the transition portion 1211.

[0338] In some examples, the protruding portion 122 and the transition portion 1211 are simultaneously welded to the first connecting portion 31 to form the entire welding imprint. Welding the first connecting portion 31 to the transition portion 1211 can effectively increase the welding area between the first connecting portion 31 and the metal layer 12, increase the current-carrying area between the first connecting portion 31 and the metal layer 12, and is conducive to improving the current-carrying capacity between the first connecting portion 31 and the metal layer 12.

[0339] 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 cyclic manner, 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 part 512, and the part located on the side of the cutting position away from the active material layer 20 is the first solder mark part 511. The first solder mark part 511 can be a convex structure of the second solder mark part 512 away from the active material layer 20. After the 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 part 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 part 122 and the active material layer 20 forms a transition part 1211.

[0340] By adopting the technical solution of this embodiment, the design of L3 / L2 = 1 makes the size of the second solder mark part 512 along the second direction relatively large, which is beneficial to designing a relatively large welding area between the first connecting part 31 and the transition part 1211. The current-carrying capacity at the connection between the first connecting part 31 and the transition part 1211 is the best, which can effectively improve the current-carrying capacity of the first electrode sheet 1, reduce the heat generation of the battery cell 100, and improve the fast charging performance of the battery cell.

[0341] In some examples, the second solder mark part 512 and the first solder mark part 511 are directly connected.

[0342] The second solder mark part 512 and the first solder mark part 511 form an integral first solder mark 51, and there is no obvious boundary between them. The integral first solder mark 51 can cover the junction of the convex part 122 and the transition part 1211. In the actual manufacturing process, the second solder mark part 512 and the first solder mark part 511 are formed by cutting the above-mentioned equal-width solder mark.

[0343] In some examples, the second welding mark portion 512 and the first welding mark portion 511 adopt the structure of welding spots, and the pitch of the welding spots in the second welding mark portion 512 is the same as that in the first welding mark portion 511; For example: the welding spots in the second welding mark portion 512 and the first welding mark portion 511 are not welded to the intersection line of the protruding portion 122 and the transition portion 1211, and the pitch between two adjacent welding spots in the second welding mark portion 512 and the first welding mark portion 511 is equal to the pitch of the welding spots in the second welding mark portion 512; For example, the welding spots are welded to the intersection line of the protruding portion 122 and the transition portion 1211, so as to connect the second welding mark portion 512 and the first welding mark portion 511 into a whole welding mark.

[0344] By adopting the technical solution of this embodiment, the first welding mark 51 can cover the intersection of the protruding portion 122 and the transition portion 1211. When a part of the current flows to the intersection of the transition portion 1211 and the protruding portion 122, it can directly flow through the first welding mark 51 to the first connection portion 31, reducing the overcurrent pressure at the intersection of the protruding portion 122 and the transition portion 1211, which is beneficial to improving the overcurrent capacity of the first pole piece 1, reducing the heat generation of the battery cell 100, and is beneficial to improving the fast charging performance of the battery cell.

[0345] In some embodiments, the number of the protruding portions 122 is multiple, and the multiple protruding portions 122 are arranged at intervals along the second direction. Each protruding portion 122 is welded to the first connection portion 31, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0346] The number of the protruding portions 122 is multiple, for example: two, three, four, etc.; The multiple protruding portions 122 are arranged at intervals along the second direction.

[0347] In some examples, after the first pole piece 1 is wound or stacked, the multiple protruding portions 122 are stacked together, and at the same time, the multiple second connection portions 32 are also stacked together, thereby breaking the insulation limitation of the insulating matrix 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, the metal layer 12.

[0348] The multiple protruding portions 122 are arranged at intervals along the second direction, so that along the second direction, the sum of the sizes of all the protruding portions 122 is smaller than the size of the main body portion 121, the sum of the sizes L4 of all the first welding mark portions 511 is smaller than the size L3 of the second welding mark portion 512, and the large size L3 of the second welding mark portion 512 is beneficial to increasing the welding area between the transition portion 1211 and the first connection portion 31, beneficial to improving the overcurrent capacity at the connection between the transition portion 1211 and the conductive member 30, beneficial to improving the overcurrent 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.

[0349] Among the multiple first welding imprint parts 511, along the second direction, the sizes of some of the first welding imprint parts 511 may be the same, or the sizes of all the first welding imprint parts 511 may be completely different, or the sizes of all the first welding imprint parts 511 may be the same.

[0350] By adopting the technical solution of this embodiment, the multiple protruding parts 122 are arranged at intervals along the second direction, which is beneficial to dividing the main body part 121 into multiple regions along the second direction, and one region can correspond to one protruding part 122. The electrons in each region can be transmitted to the electrode lead-out part 2011 through the corresponding protruding part 122, so that the electrons of the main body part 121 are transmitted in sub-regions. The electron transmission path in each region to the corresponding protruding part 122 is short, which is beneficial to reducing the electron transmission distance, reducing the overall resistance of the first pole piece 1, and improving the fast charging performance and service reliability of the single battery device 1100.

[0351] In some embodiments, the first connection part 31 includes multiple first connection sub-parts 311. The multiple first connection sub-parts 311 are arranged at intervals along the second direction. The number of the second connection parts 32 is multiple, and each first connection sub-part 311 is connected to each second connection part 32 in one-to-one correspondence; each first connection sub-part 311 is welded to the surface of each protruding part 122 facing away from the insulating substrate 11.

[0352] The first connection sub-part 311 may refer to the part of the first connection part 31 covering the protruding part 122; the number of the first connection sub-parts 311, the number of the second connection parts 32, and the number of the protruding parts 122 are the same. One first connection sub-part 311 corresponds to one protruding part 122, one first connection sub-part 311 is correspondingly connected to one second connection part 32, and one first connection sub-part 311 and one protruding part 122 are welded to form one first welding imprint part 511.

[0353] By adopting the technical solution of this embodiment, the multiple first connection sub-parts 311 of the first connection part 31 are arranged at intervals along the second direction, and there is a gap between two adjacent first connection sub-parts 311, which can reduce the material required for the first connection part 31 and reduce the manufacturing cost of the single battery device 1100.

[0354] In one embodiment, the number of the protruding portions 122 is plural, and the plural protruding portions 122 are arranged at intervals in the second direction; the first connecting portion 31 includes a second connecting sub-portion 312 and plural first connecting sub-portions 311, the plural first connecting sub-portions 311 are arranged at intervals in the second direction, and each first connecting sub-portion 311 is welded to the surface of each protruding portion 122 facing away from the insulating substrate 11 in a one-to-one correspondence; the number of the second connecting portions 32 is plural, and along the first direction, one side of each first connecting sub-portion 311 is connected to each second connecting portion 32 in a one-to-one correspondence, and the other side of each first connecting sub-portion 311 is connected to the second connecting sub-portion 312, and the second connecting sub-portion 312 is continuously arranged in the second direction; the second connecting sub-portion 312 is welded to the surface of the transition portion 1211 facing away from the insulating substrate 11.

[0355] The second connecting sub-portion 312 may refer to the portion of the first connecting portion 31 covering the transition portion 1211; the second connecting sub-portion 312 is continuously arranged in the second direction. By way of example, along the second direction, the second connecting sub-portion 312 extends from one side edge of the transition portion 1211 to the other side of the transition portion 1211.

[0356] The second connecting sub-portion 312 is welded to the surface of the transition portion 1211 facing away from the insulating substrate 11 to form a second welding mark portion 512.

[0357] By adopting the technical solution of this embodiment, the second connecting sub-portion 312 is continuously arranged in the second direction, and the plural first connecting sub-portions 311 can be connected into a whole. The second connecting sub-portion 312 can play a good supporting role for the first connecting sub-portions 311, and can reduce the risk of the first connecting sub-portions 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 single battery device 1100; in addition, along the second direction, the second connecting sub-portion 312 has a large size, which is beneficial to increasing the welding area between the second connecting sub-portion 312 and the transition portion 1211, is beneficial to improving the current-carrying capacity at the connection between the first connecting portion 31 and the transition portion 1211, improving the current-carrying capacity of the first pole piece 1, and improving the fast-charging performance and use reliability of the single battery device 1100.

[0358] In some embodiments, the number of the metal layers 12 is two, the two metal layers 12 are arranged 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 connecting 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 marks 51; the number of the insulating members 40 is two, and the first insulating portions 42 of the two insulating members 40 respectively cover at least part of the two first welding marks 51.

[0359] 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 in the thickness direction. The two active material layers 20 respectively cover the conductive portions 1212 of the two metal layers 12. The first connecting 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 mark 51. The first connecting portion 31 of the other conductive member 30 is welded to the other metal layer 12 to also form a first welding mark 51. The first insulating portions 42 of the two insulating members 40 are located on opposite sides of the insulating substrate 11 in the thickness direction and respectively cover the two first welding marks 51.

[0360] By adopting the technical solution of this embodiment, the first connecting 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 connecting 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 the second connecting portions 32 of the two conductive members 30, thereby breaking the insulation limit of the insulating substrate 11, effectively improving the conductive ability of the first electrode sheet 1, improving the fast charging performance of the single battery device 1100, reducing the heat generation of the single battery device 1100, and improving the use reliability of the single battery device 1100, the metal layer 12.

[0361] In some embodiments, the first insulating portion 42 includes a first part 421 and a second part 422 connected to each other. The first part 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 part 422 protrudes from the main body portion 121. The second part 422 is located on the side of the protruding portion 122 in the second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0362] In some examples, the insulating member 40 has an equal-width structure. The insulating member 40 covers the first welding mark 51 along the length direction of the first electrode sheet 1 and also covers the end face of the main body portion 121 facing the protruding portion 122. In the thickness direction of the current collector 10, the part of the first insulating portion 42 located within the projection range of the metal layer 12 and the conductive member 30 is the first part 421, and the part of the first insulating portion 42 located outside the projection range of the metal layer 12 and the conductive member 30 is the second part 422.

[0363] 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, relatively large burrs are likely to be formed at the end face of the transition portion 1211 facing the protruding portion 122. The first insulating portion 42 of the embodiment of the present application can prevent 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.

[0364] In some examples, the end of the main body portion 121 facing the protruding portion 122 is prone to being impacted to generate metal debris, and the metal debris is likely to fall into the electrode assembly 101, thereby causing a short - circuit of the battery cell 100. For example, the end of the transition portion 1211 facing the protruding portion 122 is prone to being impacted to generate metal debris, and the metal debris is likely to fall into the electrode assembly 101, thereby causing a short - circuit of the battery cell 100.

[0365] 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.

[0366] In some embodiments, the second parts 422 of the two insulating members 40 are in contact with each other.

[0367] 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 out of 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.

[0368] The second parts 422 of the two insulating members 40 can be pasted together or statically adsorbed together. Of course, there can also be other fitting methods.

[0369] By adopting the technical solution of this embodiment, after the second parts 422 of the two insulating members 40 are in contact with each other, 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 the metal debris and other components are not likely to fall into the electrode assembly 101, and the short - circuit risk of the battery device 1100 monomer can be better reduced.

[0370] In some embodiments, the second connection portions 32 of the two conductive members 30 are welded to form a second welding mark 52.

[0371] In some examples, along the direction from the main body portion 121 towards the protruding portion 122, the portion of the conductive member 30 protruding from the protruding portion 122 forms a second connection portion 32, such that the second connection portions 32 of the two conductive members 30 can be directly opposed and brought close to each other for welding together, and the trace left by the welding is the second welding mark 52. The second connection portions 32 of the two conductive members 30 can be welded by means such as ultrasonic welding or laser welding.

[0372] By adopting the technical solution of this embodiment, the second connection portions 32 of the two conductive members 30 can connect the metal layers 12 on the opposite sides of the insulating matrix 11, thereby breaking the insulation limitation 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 use reliability of the battery cell 100.

[0373] In some embodiments, the first insulating portion 42 covers at least a part of the second welding mark 52.

[0374] The first insulating portion 42 covers a part of the second welding mark 52, and may also cover the entire second welding mark 52.

[0375] By adopting the technical solution of this embodiment, the first insulating portion 42 can prevent burrs, metal debris and other components on the second welding mark 52 from piercing through the separator 3 and connecting to the second electrode tab 2, reducing the risk of short circuit and improving the use reliability of the battery cell.

[0376] In some embodiments, along the direction from the main body portion 121 towards the protruding portion 122, the first insulating portion 42 protrudes from the edge of the second welding mark 52 away from the main body portion 121.

[0377] By adopting the technical solution of this embodiment, the first insulating portion 42 can completely cover the second welding mark 52, prevent burrs, metal debris and other components on the entire second welding mark 52 from piercing through the separator 3 and connecting to the second electrode tab 2, reducing the risk of short circuit and improving the use reliability of the battery cell.

[0378] 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, and optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

[0379] In some examples, when the first welding mark 51 includes the first welding mark portion 511 and does not include the second welding mark portion 512, S1 is the distance from the first welding mark portion 511 to the active material layer 20.

[0380] In some examples, when the first welding mark 51 includes the first welding mark portion 511 and the second welding mark portion 512, S1 is the distance from the second welding mark portion 512 to the active material layer 20.

[0381] The design with S1≥0.3mm allows for a gap between the first welding mark 51 and the active material layer 20, preventing the conductive member 30 from being welded to the active material layer 20 and reducing the risk of problems such as false soldering. The design with S1≤5mm ensures that the gap between the first welding mark 51 and the active material layer 20 is not too large, which is beneficial for increasing the coverage area of the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell.

[0382] The value of S1 can be 0.3mm, 5mm, or any value between 0.3mm and 5mm. For example, the value of S1 can be, but is not limited to, 0.3mm, 0.5mm, 1mm, 2mm, 2.5mm, 2.8mm, 3mm, 4mm, 5mm.

[0383] By adopting the technical solution of this embodiment, the design with 0.3mm≤S1≤5mm prevents the first welding mark 51 from being welded to the active material layer 20, reducing problems such as false soldering and improving the connection reliability between the first connecting portion 31 and the metal layer 12. In addition, since the gap between the active material layer 20 and the first welding mark 51 is small, the active material layer 20 can be closer to the first welding mark 51. Therefore, when the size of the metal layer 12 in the first direction is fixed, the active material layer 20 can cover a larger area, which is beneficial for increasing the energy density of the battery cell.

[0384] In some embodiments, 0.5mm≤S1≤2.8mm.

[0385] By adopting the technical solution of this embodiment, the design with 0.5mm≤S1≤2.8mm makes the distance between the active material layer 20 and the first welding mark 51 more reasonable, better balancing the connection reliability of the conductive member 30 and the energy density of the battery cell.

[0386] In some embodiments, along the first direction, the first welding mark 51 is spaced from the end face of the first connecting portion 31 facing the active material layer 20.

[0387] In some examples, the first electrode plate 1 is a positive electrode plate, and there is a gap between the first welding mark 51 and the active material layer 20. This gap can provide a spaced 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. In addition, it can also provide a spaced space between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, preventing the first welding mark 51 from extending to the end face of the first connecting portion 31 facing the active material layer 20 and reducing the risk of the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked. This is beneficial for reducing the burrs generated during welding and improving the service reliability of the battery cell.

[0388] 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-apart 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 does not extend to the end face of the first connecting portion 31 facing the active material layer 20, reducing the risks such as being welded through or cracked at the end face of the first connecting portion 31 facing the active material layer 20, being beneficial to reducing the burrs generated by welding, and being beneficial to improving the use reliability of the battery cell; wherein, the conductive member 30 may or may not be in contact with the active material layer 20.

[0389] 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 does not extend to the end face of the first connecting portion 31 facing the active material layer 20, reducing the risks such as being welded through or cracked at the end face of the first connecting portion 31 facing the active material layer 20, being beneficial to reducing the burrs generated by welding, and being beneficial to improving the use reliability of the battery cell.

[0390] 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.

[0391] 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.

[0392] 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 does not extend to the end face of the first connecting portion 31 facing the active material layer 20, reducing the risks such as being welded through or cracked at the end face of the first connecting portion 31 facing the active material layer 20; 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 be too large, being beneficial to increasing the coverage area of the active material layer 20 on the metal layer 12 and being beneficial to improving the energy density of the battery cell.

[0393] 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.

[0394] By adopting the technical solution of this embodiment, the use reliability and energy density of the battery cell can be better balanced.

[0395] 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.

[0396] The conductive protective layer 13 may refer to a conductive structure provided between the active material layer 20 and the metal layer 12. This conductive structure can conduct electricity, enabling the battery cell to output or input electrical energy. The conductive protective layer 13 can be of an equal-thickness structure or an unequal-thickness structure.

[0397] 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.

[0398] Exemplarily, the entire conductive protective layer 13 is located between the active material layer 20 and the conductive part 1212.

[0399] 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.

[0400] 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 embodiment of the present application can separate the active material layer 20 and the metal layer 12 and play a protective role for the metal layer 12 at the same time, 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.

[0401] In some embodiments, along the direction of the main body part 121 towards the protruding part 122, the conductive protective layer 13 protrudes from the end face of the active material layer 20 towards the protruding part 122.

[0402] 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.

[0403] 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.

[0404] The protruding distance S3 of the conductive protective layer 13 from the end face of the active material layer 20 facing the protruding portion 122 is such that 0.3 mm ≤ S3 ≤ 0.8 mm. The value of S3 can be 0.3 mm, 0.8 mm, or 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.

[0405] The design with 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 pole piece 1 is better, which is beneficial to improving the fast charging performance and service reliability of the battery cell. The design with 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 and improving the energy density of the battery cell.

[0406] By adopting the technical solution of this embodiment, the current-carrying capacity and energy density of the battery cell can be better balanced.

[0407] 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.

[0408] In some examples, the conductive protective layer 13 is arranged at intervals from the first connecting portion 31, and the second 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.

[0409] 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.

[0410] Please refer to Figures 22 - 24 As shown, in some embodiments, the first insulating portion 42 is connected to the first pole piece 1.

[0411] The first insulating portion 42 can be connected to the metal layer 12, the conductive member 30, or the active material layer 20. Among them, the first insulating portion 42 can be connected to the first pole piece 1 by bonding or pasting.

[0412] By adopting the technical solution of this embodiment, the first insulating portion 42 is connected to the first pole piece 1, and the first insulating portion 42 can be fixed, thereby stably blocking the burrs at the end of the main body portion 121 facing the protruding portion 122, which is beneficial to improving the service reliability of the battery cell.

[0413] In some embodiments, the first insulating portion 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 electrode tab 1.

[0414] The first insulating portion 42 is in the form of a tape; the insulating base layer 423 may refer to the main body portion of the first insulating portion 42, and the adhesive layer 424 may refer to an adhesive covering the surface of the insulating base layer 423. The material of the first insulating portion 42 in the form of a tape 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.

[0415] By adopting the technical solution of this embodiment, the first insulating portion 42 is in the form of a tape, and the tape is easy to fully cover, which is beneficial to reducing the risk of missed coverage and reducing the risk of internal short circuit in the battery cell 100; the insulating base layer 423 can improve the structural strength of the first insulating portion 42, reduce the deformation during the fitting process of the first insulating portion 42, and is beneficial to improving the insulation effect; the adhesive layer 424 can stably fix the insulating base layer 423 on the first electrode tab 1 and reduce the risk of the insulating tape falling off.

[0416] In some embodiments, the layer thickness range of the insulating base layer 423 is 6 μm to 15 μm.

[0417] The layer thickness of the insulating base layer 423 is T1, 6 μm ≤ T1 ≤ 15 μm. It can be understood that the value of T1 can be 6 μm, 15 μm, and any value between 6 μm and 15 μm. Exemplarily, the value of T1 can be but is not limited to 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm.

[0418] The design of T1 ≥ 6 μm enables the insulating base layer 423 to have a certain thickness to block burrs and achieve insulation; the design of T1 ≤ 15 μm enables the thickness of the insulating base layer 423 not to be too large, which is beneficial to reducing the volume occupied by the first insulating portion 42 and improving the energy density of the battery cell.

[0419] By adopting the technical solution of this embodiment, the internal insulation and energy density of the battery cell can be taken into account simultaneously.

[0420] In some embodiments, the layer thickness range of the adhesive layer 424 is 0.5 μm to 3 μm.

[0421] The layer 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, and any value between 0.3 μm and 3 μm. Exemplarily, 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.

[0422] The design with T2 ≥ 0.5 μm makes the adhesive layer 424 have a certain thickness, enabling the first insulating part 42 to be stably adhered to the first pole piece 1, and the insulating reliability of the first insulating part 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 to reducing the volume occupied by the first insulating part 42 and improving the energy density of the battery cell.

[0423] By adopting the technical solution of this embodiment, the insulating reliability and energy density of the battery cell can be taken into account simultaneously.

[0424] In some embodiments, the layer thickness range of the insulating base layer 423 is 6 μm to 15 μm; the layer thickness range of the adhesive layer 424 is 0.5 μm to 3 μm.

[0425] By adopting the technical solution of this embodiment, the insulating reliability and energy density of the battery cell can be taken into account simultaneously.

[0426] In some embodiments, along the first direction, the size of the insulating member 40 is W, where 3 mm ≤ W ≤ 9 mm.

[0427] In some examples, the insulating member 40 includes a first insulating part 42, and W is equal to the size of the first insulating part 42 along the first direction.

[0428] In some examples, the insulating member 40 includes a first insulating part 42 and a second insulating part 41, and W is equal to the overall size of the first insulating part 42 and the insulating coating along the first direction.

[0429] 3 mm ≤ W ≤ 9 mm. It can be understood that the value of W can be 3 mm, 9 mm, and any value between 3 mm and 9 mm. Exemplarily, 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.

[0430] The design with W ≥ 3 mm makes the insulating member 40 have a certain size along the first direction, enabling the insulating member 40 to better block the burrs at the end of the main body part 121 facing the protruding part 122, achieving internal insulation of the battery cell 100; achieving internal insulation of the battery cell. The design with W ≤ 9 mm ensures that the size of the insulating member 40 along the first direction is not too large, which is beneficial to reducing the volume occupied by the insulating member 40 and improving the energy density of the battery cell.

[0431] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell can be taken into account simultaneously.

[0432] In some embodiments, 4.5 mm ≤ W ≤ 6.5 mm.

[0433] By adopting the technical solution of this embodiment, along the first direction, the size of the insulating member 40 is relatively reasonable, and the insulation reliability and energy density of the battery cell can be better taken into account.

[0434] In some embodiments, the electrode assembly 101 further includes a second electrode tab 2 having a polarity opposite to that of the first electrode tab 1. The second electrode tab 2 includes a main functional portion 210 and an ear portion 220. The ear portion 220 protrudes from the main functional portion 210 along the first direction; along the direction in which the main body portion 121 faces the protruding portion 122, the main functional portion 210 protrudes from the end face of the insulating member 40 close to the active material layer 20, and the main functional portion 210 does not protrude from the end face of the insulating member 40 away from the active material layer 20.

[0435] The second electrode tab 2 may refer to an electrode tab having 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.

[0436] The second electrode tab 2 includes a main functional portion 210 and an ear portion 220. The main functional portion 210 may refer to the main body portion 121 of the second electrode tab 2, and the ear portion 220 may refer to the portion of the second electrode tab 2 protruding from the main functional portion 210; when the second electrode tab 2 is a negative electrode tab, the ear portion 220 may refer to a protruding structure located at the edge of the negative current collector, and the main functional portion 210 may include the portion 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 ear portion 220 may refer to a protruding structure located at the edge of the positive current collector, and the main functional portion 210 may include the portion of the positive current collector other than the protruding structure and the positive active material layer.

[0437] During the manufacturing process of the second electrode tab 2, the edge of the second electrode tab 2 is die-cut to obtain the ear portion 220 and the main functional portion 210. During the die-cutting process, burrs are likely to be generated on the end face of the main functional portion 210 facing the ear portion 220.

[0438] Exemplarily, along the thickness direction of the current collector 10, the projection of the end face of the main functional portion 210 close to the ear portion 220 falls within the projection of the second insulating portion 41 or the projection of the first insulating portion 42.

[0439] By adopting the technical solution of this embodiment, the insulating member 40 can prevent the burrs at the end face of the main functional part 210 of the second pole piece 2 close to the pole ear part 220 from piercing through the separator 3 and connecting with the first pole piece 1, reducing the short - circuit risk between the first pole piece 1 and the second pole piece 2, and being beneficial to improving the usage reliability of the battery cell.

[0440] In some embodiments, the electrode assembly 101 further 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 functional part 210 and a pole ear part 220. The pole ear part 220 protrudes from the main functional part 210 along a first direction; along the direction of the main body part 121 towards the protruding part 122, the main functional part 210 protrudes from the end of the main body part 121 towards the protruding part 122.

[0441] In the thickness direction of the current collector 10, the projection of the end face of the main functional part 210 of the second pole piece 2 facing the pole ear part 220 does not coincide with the projection of the main body part 121, such that the burrs at the end face of the main functional part 210 of the second pole piece 2 facing the pole ear part 220 correspond to the hollowed - out area where the main body part 121 does not extend beyond the protruding part 122.

[0442] In some examples, in the thickness direction of the current collector 10, the projection of the second welding mark part 512 can fall within the projection of the main functional part 210, and the second welding mark part 512 can be covered with a first insulating part 42, such that the first insulating part 42 can prevent burrs, metal debris and other components on the first welding mark 51 from piercing through the separator 3 and connecting with the second pole piece 2, reducing the short - circuit risk and improving the usage reliability of the battery cell.

[0443] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional part 210 of the second pole piece 2 facing the pole ear part 220 correspond to the hollowed - out area where the main body part 121 does not extend beyond the protruding part 122, which can also reduce the short - circuit risk of the battery cell and improve the usage reliability of the battery cell.

[0444] In some embodiments, the electrode assembly 101 further 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 functional part 210 and a pole ear part 220. The pole ear part 220 protrudes from the main functional part 210 along a first direction; along the direction of the main body part 121 towards the protruding part 122, the main functional part 210 protrudes from the end face of the insulating member 40 close to the active material layer 20, and the main functional part 210 does not protrude from the end face of the insulating member 40 away from the active material layer 20.

[0445] 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 a part of the thickness of the conductive portion 1212 is smaller than the thickness of the transition portion 1211.

[0446] Exemplarily, the transition portion 1211 is of uniform thickness or substantially of uniform thickness, and the conductive portion 1212 is also of uniform thickness or substantially of uniform thickness. The thickness t1 of the transition portion 1211 is greater than the thickness of the conductive portion 1212.

[0447] Exemplarily, the conductive portion 1212 may have non-uniform 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 may increase in a stepped manner or increase slowly. The thickness of the part of the conductive portion 1212 far from the transition portion 1211 is smaller than the thickness of the transition portion 1211.

[0448] 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 pole piece 1, reducing the heat generation of the battery cell 100, and is beneficial to improving the fast charging performance and service reliability of the battery cell.

[0449] In some embodiments, the conductive portion 1212 includes a first sub-portion 12121 and a second sub-portion 12122. The first sub-portion 12121 is connected between the second sub-portion 12122 and the transition portion 1211. The first sub-portion 12121 and the second sub-portion 12122 are covered with the active material layer 20. The thickness of the first sub-portion 12121 is greater than the thickness of the second sub-portion 12122. The thickness of the transition portion 1211 is greater than or equal to the thickness of the first sub-portion 12121.

[0450] The conductive portion 1212 may have a non-uniform thickness structure. Along the direction from the main body portion 121 to the protruding portion 122, the conductive portion 1212 is divided into two parts. The part close to the transition portion 1211 is the first sub-portion 12121, and the part far from the transition portion 1211 is the second sub-portion 12122. Both the first sub-portion 12121 and the second sub-portion 12122 are covered with the active material layer 20.

[0451] In some examples, the first sub - part 12121 may be a structure with uniform thickness, and the second sub - part 12122 may 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 may 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 may 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.

[0452] In some examples, the first sub - part 12121 may 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 may be equal to the thickness t1 of the transition part 1211, or the thickness t1 of the transition part 1211 may also be greater than the thickness of the first segment.

[0453] During the use of the battery cell, along the direction from the main body part 121 to the protruding part 122, the electrons and ions generated by the active material layer 20 are gradually collected on the transition part 1211 through the conductive part 1212. The electrons and ions flowing through the part of the conductive part 1212 close to the transition part 1211 are more than those flowing through the part of the conductive part 1212 far from the transition part 1211. This requires that the current - carrying capacity of the part of the conductive part 1212 close to the transition part 1211 be greater than that of the part of the conductive part 1212 far from the transition part 1211.

[0454] 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, such 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 restriction on the current, improve the current - carrying capacity of the first pole piece 1, reduce the heat generation of the battery cell 100, and is beneficial to improving the use reliability of the battery cell.

[0455] In some embodiments, the current collector 10 further includes a conductive protective layer 13. The conductive protective layer 13 includes a first protective portion 131 and a second protective portion 132. The first protective portion 131 is located between the first sub-portion 12121 and the active material layer 20, and the second protective portion 132 is located between the second sub-portion 12122 and the active material layer 20. Among them, the thickness of the first protective portion 131 is less than that of the second protective portion 132, and the thickness of the third protective portion 133 is less than or equal to that of the first protective portion 131.

[0456] In some examples, along the first direction, the portion of the conductive protective layer 13 located between the first sub-portion 12121 and the active material layer 20 may be the first protective portion 131, and the portion of the conductive protective layer 13 located between the second sub-portion 12122 and the active material layer 20 may be the second protective portion 132. Among them, the thickness t4 of the first protective portion 131 is less than the thickness t5 of the second protective portion 132, and the thickness t2 of the first sub-portion 12121 is greater than the thickness t3 of the second sub-portion 12122, which can reduce the thickness difference between the current collector 10 at the first protective portion 131 and the second protective portion 132.

[0457] Exemplarily, the first sub-portion 12121 is divided into a third portion and a fourth portion. The third portion is located between the above-mentioned first section and the active material layer 20, and the fourth portion is located between the above-mentioned second section and the active material layer 20. The third portion is located between the fourth portion and the second protective portion 132. Along the direction from the main body portion 121 to the protruding portion 122, the thickness of the third portion gradually decreases, and the fourth portion is generally an equi-thickness structure, so that the thickness t4 of the first protective portion 131 can be adapted to the thickness t2 of the first sub-portion 12121, making the surface of the conductive protective layer 13 facing away from the insulating substrate 11 close to a plane.

[0458] By adopting the technical solution of this embodiment, the surface of the conductive protective 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. In addition, the problem of winding bulging of the current collector 10 can also be reduced.

[0459] In some embodiments, the conductive protective layer 13 further includes a third protective portion 133. The third protective portion 133 covers the surface of the transition portion 1211 facing away from the insulating substrate 11, and the thickness of the third protective portion 133 is less than or equal to that of the first protective portion 131.

[0460] In some examples, along the first direction, the conductive protective layer 13 can be divided into three parts. A part close to the conductive member 30 is the third protective part 133, a part far from the conductive member 30 is the second protective part 132, and the middle part is the first protective part 131. Among them, the thickness t4 of the first protective part 131 is less than the thickness t5 of the second protective part 132, while the thickness t2 of the first sub - part 12121 is greater than the thickness t5 of the second protective part 132, which can reduce the thickness difference between the collector 10 at the first protective part 131 and the second protective part 132. Similarly, the thickness t6 of the third protective part 133 is less than or equal to the thickness t4 of the first protective 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 collector 10 at the first protective part 131 and the third protective part 133, facilitating the surface of the conductive protective layer 13 facing away from the metal layer 12 to approach a plane.

[0461] Exemplarily, the second protective part 132, the third protective 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 protective part 131 are both of unequal - thickness structures. The thickness t2 of the first sub - part 12121 and the thickness t4 of the first protective part 131 are adapted to make the surface of the conductive protective layer 13 facing away from the insulating substrate 11 approach a plane.

[0462] By adopting the technical aspect of this embodiment, the setting of the third protective part 133 can make the conductive protective layer 13 protrude from the active material layer 20, enabling the active material layer 20 and the metal layer 12 to be better separated. In addition, the thickness of the third protective part 133 is not too large, which is conducive to reducing material waste and saving the manufacturing cost of the battery cell 100.

[0463] 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.

[0464] Exemplarily, the thickness t7 of the protruding part 122 can be equal to the thickness t1 of the transition part 1211, making the protruding part 122 and the transition part 1211 form an equal - thickness structure.

[0465] Exemplarily, the thickness t7 of the protruding part 122 can also be greater than the thickness t1 of the transition part 1211, making the protruding part 122 and the transition part 1211 form a stepped structure.

[0466] 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 beneficial to improving the fast - charging performance and service reliability of the battery cell.

[0467] In some embodiments, the thickness of the second active material portion 22 is t8, where 0.002 ≤ (t1 - t3) / t8 ≤ 0.08.

[0468] t1 - t3 may refer to the difference in thickness between the transition portion 1211 and the second sub-portion 12122 to characterize the thickening degree of the transition portion 1211.

[0469] (t1 - t3) / t8 can have values of 0.002, 0.08, and any value between 0.002 and 0.08; exemplarily, the value of (t1 - t3) / t8 can be but is 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.

[0470] 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 portion 1211 and the second sub-portion 12122 to be within the thickness error range of the active material layer 20. In this way, the thickening of the transition portion 1211 is not likely to cause the surface of the active material layer 20 to protrude, 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 use reliability of the battery cell.

[0471] In some embodiments, 0.003 ≤ (t1 - t3) / t8 ≤ 0.06.

[0472] 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 portion 1211 and the second sub-portion 12122 to be better within the thickness difference range of the active material layer 20. In this way, the thickening of the transition portion 1211 is even less likely to cause the surface of the active material layer 20 to protrude, 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 use reliability of the battery cell.

[0473] In some embodiments, 60μm ≤ t8 ≤ 250μm.

[0474] It can be understood that the value of t8 can be 60μm, 250μm, and any value between 60μm and 250μm; exemplarily, the value of t8 can be but is not limited to 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, 250μm.

[0475] With the design where t8≥60μm, the battery cell 100 can have a higher capacity; with the design where t3≤250μm, the distance for electrons to escape from the part of the active material layer 20 close to the metal layer 12 is not too long, and it is easy for electrons to escape from the part of the active material layer 20 close to the metal layer 12, which is beneficial to increasing the capacity of the battery cell 100.

[0476] 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, thereby improving the performance of the battery cell 100.

[0477] In some embodiments, 80μm≤t8≤180μm.

[0478] By adopting the technical solution of this embodiment, with the setting of 80μm≤t8≤180μm, the thickness of the second active material part 22 is 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, thereby improving the performance of the battery cell 100.

[0479] In some embodiments, 0.2μm≤t1 - t3≤4.5μm.

[0480] For 0.2μm≤t1 - t3≤4.5μm, it can be understood that the value of t1 - t3 can be 0.2μm, 4.5μm, and any value between 0.2μm and 4.5μm; exemplarily, 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.

[0481] 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 overcurrent capacity, the thickness of the transition part 1211 will not be too large to occupy a large space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0482] In some embodiments, 0.3μm≤t1 - t3≤1.75μm.

[0483] 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 overcurrent capacity is better, and it is more beneficial to improving the energy density of the battery cell.

[0484] In some embodiments, 1 < t1 / t3 ≤ 4, optionally, 1.5 < t1 / t3 ≤ 2.5.

[0485] t1 / t3 may refer to the ratio of the thickness t1 of the transition portion 1211 to the thickness t3 of the second sub - portion 12122, and may also characterize the thickening degree of the transition portion 1211.

[0486] For 1 < t1 / t3 ≤ 4, it can be understood that the value of t1 / t3 can be 4 and any value between 1 and 4; exemplarily, the value of t1 / t3 can be but is not limited to 1.1, 1.5, 2, 2.5, 3, 3.5, 4.

[0487] By adopting the technical solution of this embodiment, with the design of 1 < t1 / t3 ≤ 4, the thickening degree of the transition portion 1211 is reasonable. On the basis of improving the current - carrying capacity, in addition, the thickness of the transition portion 1211 is not too large to occupy a large space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0488] In some embodiments, 1.5 < t1 / t3 ≤ 2.5.

[0489] By adopting the technical solution of this embodiment, with the design of 1.5 < t1 / t3 ≤ 2.5, the thickening degree of the transition portion 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.

[0490] In some embodiments, 1 μm ≤ t1 ≤ 5 μm.

[0491] For 1 μm ≤ t1 ≤ 5 μm, it can be understood that the value of t1 can be 1 μm, 5 μm and any value between 1 μm and 5 μm; exemplarily, the value of t1 can be but is not limited to 1 μm, 1.1 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 5 μm.

[0492] By adopting the technical solution of this embodiment, with the design of 1 μm ≤ t1 ≤ 5 μm, the thickness design of the transition portion 1211 is reasonable, which is beneficial to improving the current - carrying capacity. In addition, the thickness of the transition portion 1211 is not too large to occupy a large space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0493] In some embodiments, 1.2 μm ≤ t1 ≤ 3.5 μm.

[0494] By adopting the technical solution of this embodiment, with the design of 1.2 μm ≤ t1 ≤ 3.5 μm, the thickness design of the transition portion 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.

[0495] In some embodiments, 0.03 ≤ t6 / t5 ≤ 0.95.

[0496] t6 / t5 may 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.

[0497] For 0.03 ≤ t6 / t5 ≤ 0.95, it can be understood that the value of t6 / t5 can be 0.03, 0.95, and 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.

[0498] 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, and it can be better adapted to the thickening degree of the transition part 1211, which is beneficial to the surface of the conductive protection layer 13 facing away from the metal layer 12 approaching a plane, beneficial to reducing roll pressing damage, and improving the current-carrying capacity of the metal layer 12.

[0499] In some embodiments, 0.125 ≤ t6 / t5 ≤ 0.8.

[0500] 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 be better adapted to the thickening degree of the transition part 1211, which is beneficial to the surface of the conductive protection layer 13 facing away from the metal layer 12 approaching a plane, beneficial to reducing roll pressing damage, and improving the current-carrying capacity of the metal layer 12.

[0501] In some embodiments, 0.5 μm ≤ t6 ≤ 4 μm.

[0502] For 0.5 μm ≤ t6 ≤ 4 μm, it can be understood that the value of t6 can be 0.5 μm, 4 μm, and any value between 0.5 μm and 4 μm; by way of 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.

[0503] 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, thus 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 facing away from the metal layer 12 due to the excessive thickness of the third protection part 133, and it can also reduce material accumulation and production costs.

[0504] In some embodiments, 1 μm ≤ t6 ≤ 2 μm.

[0505] By adopting the technical solution of this embodiment, the setting of 1μm≤t6≤2μm makes the third protection part 133 have a more reasonable thickness, thereby better reducing the cracking risk of the metal layer 12 and the manufacturing cost.

[0506] 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.

[0507] Exemplarily, 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.

[0508] 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.

[0509] For 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; exemplarily, 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.

[0510] 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 is beneficial to improving the energy density of the battery cell 100.

[0511] In some embodiments, along the first direction, the size of the first sub - part 12121 is W2, where 10mm≤W2≤100mm.

[0512] It can be understood that the value of W2 can be 10mm, 100mm and any value between 10mm and 100mm; exemplarily, the value of W2 can be but is not limited to 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm.

[0513] 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 will not occupy too much area, which is beneficial to reducing the occupied space and weight of the first sub - part 12121 and is conducive to improving the energy density of the battery cell 100.

[0514] The battery cells of the present application will be described below in conjunction with some embodiments.

[0515] Embodiment 1

[0516] Refer to Figures 3 - 11 As shown, in this embodiment, the battery cell includes an end - cover 201, a housing 202 and an electrode assembly 101. The electrode assembly 101 is installed at the housing 202, and the end - cover 201 covers the opening of the housing 202 to seal the housing 202. The end - cover 201 is provided with an electrode lead - out part 2011.

[0517] In this embodiment, the electrode assembly 101 includes a first electrode tab 1, a second electrode tab 2 and a separator 3 which are wound. The separator 3 is located between the first electrode tab 1 and the second electrode tab 2, and 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.

[0518] 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 two opposite surfaces of the insulating substrate 11 in the thickness direction are covered with the metal layer 12. The surface of the metal layer 12 facing away from the insulating substrate is covered with the conductive protective layer 13, and the surface of the conductive protective layer 13 facing away from the insulating substrate is covered with the active material layer 20.

[0519] In this embodiment, the two metal layers 12 are both welded with the conductive member 30. The conductive member 30 includes a first connection part 31 and a second connection part 32 which are connected. The first connection part 31 is welded with the metal layer 12 to form a first weld mark 51, and the second connection parts 32 of the two conductive members 30 are welded to form a second weld mark 52.

[0520] In this embodiment, the electrode assembly 101 further includes an insulating member 40. The insulating member 40 includes a second insulating part 41, and the second insulating part 41 is located between the first connection part 31 and the active material layer 20.

[0521] 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. The active material layer 20 covers the metal layer 12, and the protruding portion 122 and the transition portion 1211 are not covered by the active material layer 20. The first direction is perpendicular to the thickness direction of the current collector 10.

[0522] In this embodiment, the number of the protruding portions 122 is multiple, and the multiple protruding portions 122 are arranged at intervals in a second direction. The second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0523] 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 sub-portion 5112. The first welding mark sub-portion 5111 and the second welding mark sub-portion 5112 form a first welding mark portion 511, and the first welding mark portion 511 is the first welding mark 51.

[0524] In this embodiment, the insulating member 40 includes a first insulating portion 42. The first insulating portion 42 covers the first welding mark 51, and in the direction from the main body portion 121 to the protruding portion 122, the first insulating portion 42 protrudes from the end of the main body portion 121 facing the protruding portion 122.

[0525] Embodiment Two

[0526] Refer to Figures 12 - 18 As shown, the difference between this embodiment and Embodiment One is that: the first connecting portion 31 is welded to the protruding portion 122 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.

[0527] In this embodiment, the insulating member 40 further includes a first insulating portion 42. One side of the first insulating portion 42 covers the first welding mark 51 and the second welding mark 52, and the other side covers the second insulating portion 41.

[0528] 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.

[0529] Embodiment III

[0530] The difference between this embodiment and Embodiment II is as follows: Refer to Figures 19 - 22 As shown, the insulating member 40 includes a first insulating portion 42 and does not include a second insulating portion 41. One side of the first insulating portion 42 covers the first solder mark 51, and the other side of the first insulating portion 42 covers the active material layer 20.

[0531] In some embodiments, refer to Figure 2 As shown, a battery device 1100 is provided, including the battery cell of the above embodiment.

[0532] For the battery device 1100 of the embodiment of the present application, the above-mentioned battery cell is adopted, and the use reliability of the battery cell is good, which is beneficial to improving the use reliability of the battery device 1100.

[0533] In some embodiments, refer to Figure 1 As shown, an electrical device is provided, including the battery device 1100 as in the above embodiment.

[0534] For the battery device 1100 of the embodiment of the present application, the above-mentioned battery cell is adopted, and the use reliability of the battery device 1100 is good, which is beneficial to improving the use reliability of the electrical device.

[0535] The descriptions of the above embodiments tend to emphasize the differences between the embodiments. Their similarities or similarities can be referred to each other. For the sake of brevity, they will not be elaborated herein.

[0536] 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 in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, Comprising: A housing provided with an electrode lead-out portion; An electrode assembly, at least partially accommodated in the housing, the electrode assembly including a first electrode tab and an insulating member, the first electrode tab including a conductive member, a current collector, and an active material layer; The current collector includes an insulating substrate and a metal layer, and the conductive member connects the electrode lead-out portion and the metal layer; The insulating substrate, the metal layer, and the active material layer are stacked in 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 portion and at least one protruding portion, the protruding portion extending outward from an end of the main body portion in a first direction, the first direction being perpendicular to the thickness direction of the current collector; At least a portion of the main body portion is covered with the active material layer, and at least a portion of the protruding portion is not covered with the active material layer; The insulating member includes a first insulating portion located on a side of the main body portion facing away from the insulating substrate; in a direction from the main body portion towards the protruding portion, the first insulating portion protrudes from an end of the main body portion facing the protruding portion.

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

3. The battery cell according to claim 2, characterized in that: The first insulating portion covers at least a portion of the first weld mark.

4. The battery cell according to claim 2, wherein: In the first direction, the first connecting portion and the active material layer are spaced apart.

5. The battery cell according to claim 2, characterized in that, The insulating member includes a second insulating portion covering a surface of the metal layer facing away from the insulating substrate, and the entire second insulating portion is located between the first weld mark and the active material layer.

6. The battery cell according to claim 5, characterized in that: The second insulating portion is located between the first connecting portion and the active material layer.

7. The battery cell according to claim 6, characterized in that: In the first direction, one side of the first insulating portion covers the first weld mark, and the other side of the first insulating portion covers at least a portion of the second insulating portion.

8. The battery cell according to any one of claims 2 to 7, characterized in that: In the first direction, one side of the first insulating portion covers the first weld mark, and the other side of the first insulating portion covers at least a portion of the active material layer.

9. The battery cell according to any one of claims 2 to 7, characterized in that: The first weld mark includes a first weld mark portion, the first connecting portion is welded to a surface of the protruding portion facing away from the insulating substrate to form the first weld mark portion, and the first insulating portion covers at least a portion of the first weld mark portion.

10. The battery cell according to claim 9, wherein: The first weld mark portion includes a first weld mark sub-portion, the protruding portion includes a first protruding sub-portion and a second protruding sub-portion, and the first protruding sub-portion is connected between the second protruding sub-portion and the main body portion; In a second direction, the size of the first protruding sub-portion is larger than the size of the second protruding sub-portion, the second direction being perpendicular to the first direction and the thickness direction of the current collector; The first connecting portion is welded to the surface of the first protruding sub-portion facing away from the insulating substrate to form the first welding imprint sub-portion, and the first insulating portion covers at least a part of the first welding imprint sub-portion.

11. The battery cell according to claim 10, wherein: Along the direction from the main body portion to the protruding portion, the first insulating portion protrudes from the end face of the first protruding sub-portion facing away from the main body portion.

12. The battery cell according to claim 10, characterized in that: Along the second direction, the first welding imprint sub-portion extends from one side edge of the first protruding sub-portion to the other side edge of the first protruding sub-portion.

13. The battery cell according to claim 10, wherein: The first welding imprint portion further includes a second welding imprint sub-portion. 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 imprint sub-portion, and the first insulating portion covers at least a part of the second welding imprint sub-portion.

14. The battery cell according to claim 13, wherein: Along the direction from the main body portion to the protruding portion, the first insulating portion protrudes from the edge of the second welding imprint sub-portion facing away from the first protruding sub-portion.

15. The battery cell according to claim 13, characterized in that: Along the second direction, the second welding imprint sub-portion extends from one side edge of the second protruding sub-portion to the other side edge of the second protruding sub-portion.

16. The battery cell according to any one of claims 2 to 7, characterized in that: The number of the protruding portions is multiple, and the multiple protruding portions are arranged at intervals along the second direction. Each protruding portion is welded to the first connecting portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector.

17. The battery cell according to claim 16, characterized in that: The first connecting portion includes multiple first connecting sub-portions, and 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 of the first connecting sub-portions is connected to each of the second connecting portions in a one-to-one correspondence; Each of the first connecting sub-portions is welded to the surface of each of the protruding portions facing away from the insulating substrate in a one-to-one correspondence.

18. The battery cell according to any one of claims 2 to 7, characterized in that: The main body portion includes a conductive portion and a transition portion. The transition portion is connected between the conductive portion and the protruding portion. The transition portion and the protruding portion are not covered with the active material layer, and the conductive portion is covered with the active material layer; the first insulating portion covers at least a part of the surface of the transition portion facing away from the insulating substrate; Along the direction from the main body portion to the protruding portion, the first insulating portion protrudes from the end of the transition portion facing away from the conductive portion.

19. The battery cell according to claim 18, wherein: Along the second direction, the size of the conductive portion is L1, and the size of the transition portion is L2, where 0.8 ≤ L2 / L1 ≤ 1. Here, the second direction is perpendicular to the first direction and the thickness direction of the current collector.

20. The battery cell according to claim 18, wherein: The first welding imprint further includes a second welding imprint portion. The first connecting portion is welded to the surface of the transition portion facing away from the insulating substrate to form the second welding imprint portion, and the first insulating portion covers at least a part of the second welding imprint portion.

21. The battery cell according to claim 20, wherein: Along the direction from the protruding portion to the main body portion, the first insulating portion protrudes from the edge of the second welding imprint portion facing the active material layer.

22. The battery cell according to claim 20, wherein: Along the second direction, the size of the transition portion is L2, and the size of the second welding imprint portion is L3, where 0.8 ≤ L3 / L2 ≤ 1. Here, the second direction is perpendicular to the first direction and the thickness direction of the current collector.

23. The battery cell according to claim 18, wherein: The number of the protruding portions is multiple, and the multiple protruding portions are arranged at intervals along the second direction. The second direction is perpendicular to the first direction and the thickness direction of the current collector; 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 in the second direction, and each of the first connecting sub-portions is welded to the surface of each of the protruding portions facing away from the insulating substrate one by one; The number of the second connecting portions is a plurality. Along the first direction, one side of each of the first connecting sub-portions is connected to each of the second connecting portions one by one, and the other side of each of the first connecting sub-portions is connected to the second connecting sub-portion. The second connecting sub-portion is continuously arranged in the second direction; The second connecting sub-portion is welded to the surface of the transition portion facing away from the insulating substrate.

24. The battery cell according to any one of claims 2 to 7, characterized in that: The number of the metal layers is two. The two metal layers are arranged on opposite sides of the insulating substrate in the thickness direction of the current collector. The number of the active material layers is two. The two active material layers respectively cover the two metal layers; The number of the conductive members is two. The first connecting 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 solder marks; The number of the insulating members is two. The first insulating portions of the two insulating members respectively cover at least part of the two first solder marks.

25. The battery cell according to claim 24, characterized in that: The first insulating portion includes a first part and a second part connected to each other. The first part covers at least part of the main body portion. Along the direction of the main body portion facing the protruding portion, the second part protrudes from the main body portion. The second part is located on the side of the protruding portion in the second direction. The second direction is perpendicular to the first direction and the thickness direction of the current collector.

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, wherein: The second connecting portions of the two conductive members are welded to form a second solder mark.

28. The battery cell according to claim 27, wherein: The first insulating portion covers at least part of the second solder mark.

29. The battery cell according to claim 28, characterized in that: Along the direction of the main body portion pointing to the protruding portion, the first insulating portion protrudes from the edge of the second solder mark away from the main body portion.

30. The battery cell according to any one of claims 2 to 7, characterized in that: Along the first direction, the distance between the first solder mark and the active material layer is S1, where 0.3 mm ≤ S1 ≤ 5 mm. Optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

31. The battery cell according to any one of claims 2 to 7, characterized in that: 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.

32. The battery cell according to claim 31, wherein: Along the direction of the main body portion facing the protruding portion, the conductive protective layer protrudes from the end face of the active material layer facing the protruding portion.

33. The battery cell according to claim 32, characterized in that: The protruding length range of the conductive protective layer protruding from the end face of the active material layer facing the protruding portion is 0.3 mm to 0.8 mm along the direction of the main body portion facing the protruding portion.

34. The battery cell according to claim 31, wherein: Along the first direction, the conductive protective layer and the first solder mark are arranged at intervals.

35. The battery cell according to any one of claims 1 to 7, characterized in that: Along the first direction, the size of the part of the insulating member covering the active material layer is H, where 0.2 mm ≤ H ≤ 1.0 mm. Optionally, 0.3 mm ≤ H ≤ 0.8 mm.

36. The battery cell according to any one of claims 1 to 7, characterized in that: The first insulating portion is connected to the first pole piece.

37. The battery cell according to claim 36, characterized in that: The first insulating portion includes an insulating base layer and an adhesive layer. The adhesive layer is bonded between the insulating base layer and the first pole piece.

38. The battery cell according to claim 37, wherein: The layer thickness of the insulating base layer ranges from 6 μm to 15 μm; and / or, the layer thickness of the adhesive layer ranges from 0.5 μm to 3 μm.

39. The battery cell according to any one of claims 1 to 7, characterized in that: Along the first direction, the size of the insulating member is W, where 3 mm ≤ W ≤ 9 mm, and optionally, 4.5 mm ≤ W ≤ 6.5 mm.

40. The battery cell according to any one of claims 1 to 7, characterized in that: The electrode assembly further includes a second electrode tab having a polarity opposite to that of the first electrode tab. The second electrode tab includes a main functional portion and an electrode ear portion, and the electrode ear portion protrudes from the main functional portion along the first direction. Along the direction from the main body portion towards the protruding portion, the main functional portion protrudes from the end face of the insulating member close to the active material layer, and the main functional portion does not protrude from the end face of the insulating member away from the active material layer.

41. The battery cell according to any one of claims 1 to 7, characterized in that: The electrode assembly further includes a second electrode tab having a polarity opposite to that of the first electrode tab. The second electrode tab includes a main functional portion and an electrode ear portion, and the electrode ear portion protrudes from the main functional portion along the first direction. Along the direction from the main body portion towards the protruding portion, the main functional portion protrudes from the end of the main body portion towards the protruding portion.

42. The battery cell according to any one of claims 1 to 7, 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 member; at least part of the thickness of the conductive portion is less than the thickness of the transition portion.

43. The battery cell according to claim 42, wherein: 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.

44. The battery cell according to claim 43, characterized in that: 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.

45. The battery cell according to claim 44, wherein: The conductive protective layer further includes a third protective portion. The third protective portion 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.

46. The battery cell according to claim 42, wherein: The thickness of the protruding portion is greater than or equal to the thickness of the transition portion.

47. A battery device, characterized in that: Including the battery cell according to any one of claims 1 to 46.

48. An electrical device, characterized in that: Including the battery device according to claim 47.

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