Battery monomer, battery device and electric device

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a single battery, a battery device and a power utilization device.The single battery comprises a shell and an electrode assembly, and the shell is provided with an electrode leading-out part; at least part of the electrode assembly is accommodated in the shell, the electrode assembly comprises a first pole piece and a first insulating part, the first pole piece comprises a conductive component, a current collector and an active substance layer, and the current collector comprises an insulating substrate and a metal layer; the metal layer comprises a main body part; the main body part comprises a transition part and a conductive part; the conductive part is at least partially covered with an active material layer, and the transition part is not covered with the active material layer; the conductive component comprises a first connecting part connected with the metal layer and a second connecting part electrically connected with the electrode leading-out part, the first connecting part comprises a first connecting sub-part, and the first connecting sub-part covers the surface, back on to the insulating substrate, of the transition part; along the direction from the conductive part to the transition part, the first insulating part protrudes out of the edge of the first connector part away from the active material layer, thereby reducing the short-circuit risk of the battery monomer.

Description

[0001] This application claims priority to international patent application PCT / CN2024 / 106988, filed on July 23, 2024, entitled “Battery Cell, Battery Device, and Electrical Device,” and the entire contents of the above application are incorporated herein by reference. Technical Field

[0002] The present application belongs to the field of battery technology, and in particular relates to a battery cell, a battery device, and an electrical device. Background Art

[0003] Battery cells are widely used in electronic devices such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0004] A battery device includes one or more battery cells to meet different capacity usage requirements. However, in battery cell technology, how to improve the reliability of battery cells is an important research direction.

[0005] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art. Utility Model Content

[0006] The purpose of the embodiments of the present application is to provide a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery cell.

[0007] The technical solution adopted in the embodiment of this application is:

[0008] On the first aspect, in some embodiments, a battery cell includes a shell and an electrode assembly, the shell is provided with an electrode lead-out portion; at least a portion of the electrode assembly is accommodated in the shell, the electrode assembly includes a first pole piece and a first insulating member, the first pole piece includes a conductive component, a current collector and an active material layer, the current collector includes an insulating substrate and a metal layer; the insulating substrate, the metal layer and the active material layer are stacked along the thickness direction of the current collector, and at least a portion of the metal layer is located between the insulating substrate and the active material layer; the metal layer includes a main body, the main body includes a transition portion and a conductive portion arranged and connected along a first direction, the first direction is perpendicular to the thickness direction of the current collector; at least a portion of the conductive portion is covered with the active material layer, and the transition portion is not covered with the active material layer; the conductive member includes a connected first connecting portion and at least one second connecting portion, the first connecting portion is connected to the metal layer, the second connecting portion is electrically connected to the electrode lead-out portion, the first connecting portion includes a first connecting sub-portion, the first connecting sub-portion covers the surface of the transition portion facing away from the insulating substrate; along the direction from the conductive portion to the transition portion, the first insulating member protrudes from the edge of the first connecting sub-portion away from the active material layer.

[0009] By adopting the technical solution of this embodiment, the first insulating part can block the burrs, metal debris and other components at the edge of the first connecting sub-part away from the active material layer, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell. In addition, the current collector adopts a composite structure of an insulating substrate and a metal layer. Compared with the pure metal current collector, the thickness of the metal layer is small, and the burrs generated by the current collector during the manufacturing process are smaller, which reduces the internal short circuit risk of the battery cell and is conducive to improving the reliability of the battery cell.

[0010] In some embodiments, along a direction from the transition portion to the conductive portion, the first insulating member protrudes beyond the first connecting sub-portion close to an edge of the active material layer.

[0011] By adopting the technical solution of this embodiment, the first insulating part can cover the edge of the first connecting sub-part close to the active material layer, thereby blocking burrs, metal debris and other components at the edge of the first connecting sub-part close to the active material layer, reducing the short circuit risk of the battery cell, and improving the reliability of the battery cell; in addition, the first insulating part can cover the entire first connecting sub-part to achieve overall insulation of the first connecting sub-part, which can effectively reduce the short circuit of the battery cell and improve the reliability of the battery cell.

[0012] In some embodiments, along the first direction, an edge of the transition portion away from the conductive portion is flush with an edge of the first connecting sub-portion away from the active material layer.

[0013] By adopting the technical solution of this embodiment, along the first direction, the edge of the transition part away from the conductive part is flush with the edge of the first connecting sub-part away from the active material layer. The structure of the first pole piece is regular, which is convenient for processing and manufacturing. It can also reduce the redundancy of the first connecting sub-part or the transition part, save space, and improve the energy density of the battery cell. In addition, the first insulating part also protrudes from the edge of the transition part away from the active material layer, blocking burrs, metal debris and other components at the edge of the transition part away from the active material layer, reducing the short circuit risk of the battery cell, and improving the reliability of the battery cell.

[0014] In some embodiments, along the second direction, a size of the conductive portion is L1, a size of the transition portion is L2, and 0.8≤L2 / L1≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0015] By adopting the technical solution of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition portion along the second direction large, which is beneficial to increasing the connection area between the first connecting sub-portion and the transition portion, improving the current flow capacity between the first connecting sub-portion and the transition portion, improving the current flow capacity of the first pole piece, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell.

[0016] In some embodiments, the first connection portion is welded to a surface of the metal layer facing away from the insulating substrate to form a first weld mark. Along the first direction, the first weld mark is located on a side of the active material layer close to the transition portion.

[0017] By adopting the technical solution of this embodiment, the first connecting portion is welded to the metal layer, the welding operation is simple, and the production and processing of the first electrode sheet are convenient; the first weld mark is located on the side of the active material layer close to the transition portion, so that the first weld mark is separated from the active material layer, reducing the risk of cold welding between the first connecting portion and the metal layer due to the active material layer, which is beneficial to improving the reliability of the battery cell.

[0018] In some embodiments, the first insulating member covers at least a portion of the first weld print.

[0019] By adopting the technical solution of this embodiment, the first insulating member can block burrs, metal debris and other components on the first weld mark, reduce the short circuit risk of the battery cell, and improve the reliability of the battery cell.

[0020] In some embodiments, the first weld print includes a first weld print portion, and the first connecting sub-portion is welded to a surface of the transition portion facing away from the insulating base to form the first weld print portion.

[0021] By adopting the technical solution of this embodiment, the first connecting sub-part is welded to the transition part, so that the current can flow directly to the conductive component through the transition part, which is beneficial to improving the current flow capacity of the first pole piece and improving the fast charging performance of the battery cell.

[0022] In some embodiments, along the second direction, a size of the transition portion is L2, a size of the first weld print is L3, and 0.8≤L3 / L2≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0023] By adopting the technical solution of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the first weld portion along the second direction larger, which is beneficial to increasing the connection area between the first connecting sub-portion and the transition portion, improving the flow capacity of the connection between the first connecting sub-portion and the transition portion, improving the flow capacity of the first pole piece, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell.

[0024] In some embodiments, the first insulating member covers at least a portion of the first weld print.

[0025] By adopting the technical solution of this embodiment, the first insulating member can block burrs, metal debris and other components on the first weld print portion, reduce the short circuit risk of the battery cell, and improve the reliability of the battery cell.

[0026] In some embodiments, along the direction from the transition portion to the conductive portion, the first insulating member protrudes from the first weld portion close to the edge of the active material layer; and / or, along the direction from the conductive portion to the transition portion, the first insulating member protrudes from the first weld portion away from the edge of the active material layer.

[0027] By adopting the technical solution of this embodiment, the first insulating member can cover the edges of the first weld print portion that are relatively distributed along the first direction, and can block burrs, metal debris and other components at the edges of the first weld print portion that are relatively distributed along the first direction, thereby effectively reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0028] In some embodiments, along the first direction, an edge of the first weld portion away from the active material layer is flush with an edge of the first connecting sub-portion away from the active material layer.

[0029] By adopting the technical solution of this embodiment, along the first direction, the edge of the first weld mark away from the active material layer is flush with the edge of the first connecting sub-portion away from the active material layer, the structure of the first pole piece is regular, the processing and manufacturing of the first pole piece can be facilitated, the redundancy of the first connecting sub-portion can be reduced, space can be saved, and the energy density of the battery cell can be improved; in addition, the first insulating part also protrudes from the edge of the first weld mark away from the active material layer, and the first insulating part can cover the edge of the first weld mark away from the active material layer, thereby blocking the burrs at the edge of the first weld mark away from the active material layer, reducing the short circuit risk of the battery cell, and improving the reliability of the battery cell.

[0030] In some embodiments, along the second direction, two opposite edges of the transition portion are flush with two opposite edges of the first connecting sub-portion, and two opposite edges of the first welded portion are flush with two opposite edges of the first connecting sub-portion.

[0031] By adopting the technical solution of this embodiment, the structures of the two side surfaces of the first pole piece relatively distributed along the second direction are regular, which can facilitate the processing and production of the first pole piece, reduce the redundancy of the first connecting sub-part and the transition part, save space, and improve the energy density of the battery cell; in addition, along the second direction, the size of the first welded part is equal to the size of the transition part, which increases the welding area between the transition part and the first connecting sub-part, which is beneficial to improving the current flow capacity of the first pole piece and improving the fast charging performance of the battery cell.

[0032] In some embodiments, the metal layer also includes at least one protrusion, and the transition portion is connected between the protrusion and the conductive portion; along the second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the transition portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; the first connecting portion includes at least one second connecting sub-portion, the second connecting sub-portion is connected between the first connecting sub-portion and the second connecting portion, and the second connecting sub-portion covers the surface of the protrusion facing away from the insulating substrate, and the second connecting sub-portion and the protrusion correspond one to one.

[0033] By adopting the technical solution of this embodiment, along the second direction, the size of the protrusion is smaller than the size of the transition portion, which can eliminate the edge redundancy of the current collector, save space, and improve the energy density of the battery cell; in addition, the protrusion can also be connected to the second connecting sub-part, thereby increasing the connection area between the metal layer and the first connecting part, improving the current flow capacity between the metal layer and the first connecting part, and improving the fast charging performance of the battery cell.

[0034] In some embodiments, the first weld print includes at least one second weld print portion, and the second connecting sub-portion is welded to the corresponding protruding portion to form a second weld print portion.

[0035] By adopting the technical solution of this embodiment, the second connecting sub-part is welded to the protruding part, thereby achieving connection between the first connecting part and the metal layer.

[0036] In some embodiments, the first insulating member covers at least a portion of the second weld print.

[0037] By adopting the technical solution of this embodiment, the first insulating member can block burrs, metal debris and other components on the second weld print portion, reduce the short circuit risk of the battery cell, and improve the reliability of the battery cell.

[0038] In some embodiments, along the direction from the transition portion to the conductive portion, the first insulating member protrudes from the second weld mark portion close to the edge of the active material layer; and / or, along the direction from the conductive portion to the transition portion, the first insulating member protrudes from the second weld mark portion away from the edge of the active material layer.

[0039] By adopting the technical solution of this embodiment, the first insulating member can cover the edges of the second weld print portion that are relatively distributed along the first direction, and can block burrs, metal debris and other components at the edges of the second weld print portion that are relatively distributed along the first direction, thereby effectively reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0040] In some embodiments, along the direction from the transition portion to the conductive portion, the first insulating member protrudes from the second connecting sub-portion close to the edge of the active material layer; and / or, along the direction from the conductive portion to the transition portion, the first insulating member protrudes from the second connecting sub-portion away from the edge of the active material layer.

[0041] By adopting the technical solution of this embodiment, the first insulating part can cover the edges of the second connecting sub-part that are relatively distributed along the first direction, and can block burrs, metal debris and other components at the edges of the second connecting sub-part that are relatively distributed along the first direction, thereby effectively reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0042] In some embodiments, the first insulating member includes a first insulating portion and at least one second insulating portion, the first insulating portion covers the first connecting sub-portion, the second insulating portion covers the second connecting sub-portion, and the second insulating portion corresponds to the second connecting sub-portion one-to-one.

[0043] By adopting the technical solution of this embodiment, the first insulating member can cover the first connecting sub-portion and the second connecting sub-portion, thereby increasing the coverage area of ​​the first insulating member, improving the insulation effect of the first insulating member, reducing the short circuit risk of the battery cell, and improving the reliability of the battery cell.

[0044] In some embodiments, along the second direction, at least one of the two opposite sides of the first insulating portion protrudes beyond a corresponding side surface of the first connecting sub-portion.

[0045] By adopting the technical solution of this embodiment, the first insulating portion can block the burrs on the side surface of the first connecting sub-portion along the second direction, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0046] In some embodiments, there are multiple protrusions, there are multiple second connecting sub-parts, multiple protrusions are arranged at intervals along the second direction, multiple second connecting sub-parts are arranged at intervals along the second direction, multiple protrusions and multiple second connecting sub-parts are arranged in one-to-one correspondence, there are multiple second connecting parts, multiple second connecting parts are arranged at intervals along the second direction, the second connecting sub-parts are connected to the second connecting parts in one-to-one correspondence, and multiple second connecting sub-parts are connected to the edge of the first connecting sub-part facing away from the active material layer; the first connecting sub-parts are continuously arranged along the second direction; there are multiple second insulating parts, multiple second insulating parts are arranged along the second direction, and the second insulating parts correspond to the second connecting sub-parts one-to-one.

[0047] By adopting the technical solution of this embodiment, the first connecting sub-portion is continuously arranged along the second direction, and multiple second connecting sub-portions can be connected into a whole. The first connecting sub-portion can provide good support for the second connecting sub-portion, which can reduce the risk of the second connecting sub-portion being inserted between the first electrode sheet and the second electrode sheet when being bent, reduce the risk of short circuit of the battery cell, and help improve the reliability of the battery cell; along the second direction, the size of the first connecting sub-portion is large, which is conducive to increasing the welding area between the first connecting sub-portion and the transition portion, and is conducive to improving the flow capacity between the first connecting sub-portion and the transition portion, improving the flow capacity of the first electrode sheet, and improving the fast charging performance and reliability of the battery cell; multiple protrusions are arranged at intervals along the second direction, which is conducive to dividing the main body into multiple regions along the second direction, and each region can correspond to one protrusion. The electrons in each region can be transmitted to the electrode lead-out portion through the corresponding protrusion, which can realize the regional transmission of electrons in the main body. The electron transmission path in each region is short to the corresponding protrusion, which is conducive to reducing the transmission distance of the electrons, reducing the overall resistance of the first electrode sheet, and improving the fast charging performance and reliability of the battery cell.

[0048] In some embodiments, two adjacent second insulating portions are connected.

[0049] By adopting the technical solution of this embodiment, two adjacent second insulating parts can be directly connected to form an integral structure, which can facilitate the installation of the first insulating part; at the same time, the second insulating part can also cover the two opposite edges of the second connecting sub-part along the second direction, blocking the pointed protrusions, metal debris and other components on the two opposite side surfaces of the second connecting sub-part along the second direction, thereby increasing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0050] In some embodiments, along the first direction, the first weld print and the active material layer are spaced apart.

[0051] By adopting the technical solution of this embodiment, a gap is formed between the first weld mark and the active material layer, so that the welding of the first connecting part and the metal layer will not be welded to the active material layer, reducing the risk of cold welding between the first connecting part and the metal layer and improving the reliability of the battery cell.

[0052] In some embodiments, along the first direction, a distance between the first weld mark and the active material layer is S1, wherein 0.3 mm ≤ S1 ≤ 5 mm, optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

[0053] By adopting the technical solution of this embodiment, the design of 0.3mm≤S1≤5mm ensures that the first weld mark will not be welded to the active material layer, reducing the risk of cold welding between the first connection part and the metal layer, which is beneficial to improving the connection reliability between the first connection part and the metal layer, and improving the reliability of the battery cell. In addition, the spacing between the active material layer and the first weld mark is reasonable, and the active material layer is close to the first weld mark. Then, when the size of the metal layer in the first direction is constant, the active material layer can cover a larger area, which is beneficial to improving the energy density of the battery cell.

[0054] In some embodiments, the electrode assembly includes a second insulating member, which covers the surface of the metal layer facing away from the insulating substrate, and the entire second insulating member is located between the first weld mark and the active material layer.

[0055] By adopting the technical solution of this embodiment, the second insulating member covers the portion of the metal layer between the first weld mark and the active material layer, thereby achieving insulation of this portion, which is beneficial to reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0056] In some embodiments, along the first direction, the first connecting sub-portion is spaced apart from the active material layer.

[0057] By adopting the technical solution of this embodiment, the first connecting sub-portion is not in contact with the active material layer, which can reduce the mutual influence between the two and is conducive to improving the performance of the battery cell.

[0058] In some embodiments, at least a portion of the second insulating member is located between the first connecting sub-part and the active material layer.

[0059] By adopting the technical solution of this embodiment, the second insulating member covers the portion of the transition part located between the first connecting sub-part and the active material layer. The second insulating member can support this portion, thereby reducing the risk of cracks in this portion. In addition, the second insulating member covers the portion of the transition part located between the first connecting sub-part and the active material layer, and can also achieve insulation of this portion, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0060] In some embodiments, the electrode assembly also includes a second pole piece with opposite polarity to the first pole piece, and the second pole piece includes a main functional portion and a pole ear portion arranged along the first direction, the end of the main functional portion close to the transition portion has a first end face, and the pole ear portion extends outward from the first end face; along the thickness direction of the current collector, the projection of the first end face is located within the projection of the second insulating member.

[0061] By adopting the technical solution of this embodiment, the first end face and the second insulating member are arranged opposite to each other, and the second insulating member can block the burrs at the first end face, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0062] In some embodiments, along the first direction, one side of the first insulating member covers the first connecting sub-portion, and the other side of the first insulating member covers at least a portion of the second insulating member.

[0063] By adopting the technical solution of this embodiment, the first insulating member and the second insulating member can achieve double-layer insulation, thereby reducing the short-circuit risk of the battery cell and improving the reliability of the battery cell.

[0064] In some embodiments, along the first direction, one side of the first insulating member covers the first connecting sub-portion, and the other side of the first insulating member covers at least a portion of the active material layer.

[0065] By adopting the technical solution of this embodiment, the first insulating member has a wide coverage area and a good insulating effect, which is beneficial to improving the reliability of the battery cell; the first insulating member can cover the end of the active material layer close to the transition part, and can block the burrs of the active material layer close to the transition part, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0066] In some embodiments, along the first direction, a size of a portion of the first insulating member covering the active material layer is H, wherein 0.2 mm ≤ H ≤ 1.0 mm, optionally, 0.3 mm ≤ H ≤ 0.8 mm.

[0067] By adopting the technical solution of this embodiment, along the first direction, the size of the portion of the first insulating member covering the active material layer is reasonable, which can simultaneously take into account the problem of blocking burrs at the end of the active material layer near the transition part and the energy density of the battery cell.

[0068] In some embodiments, the electrode assembly also includes a second electrode plate with opposite polarity to the first electrode plate, and the second electrode plate includes a main functional portion and a pole ear portion arranged along a first direction, the end of the main functional portion close to the transition portion has a first end face, and the pole ear portion extends outward from the first end face; along the direction of the conductive portion toward the transition portion, the side of the first connecting sub-portion away from the active material layer does not protrude beyond the first end face; or, along the thickness direction of the current collector, the projection of the first end face is located within the projection of the first connecting sub-portion.

[0069] By adopting the technical solution of this embodiment, the side of the first connector away from the active material layer does not protrude beyond the first end surface, allowing the first end surface to be positioned opposite the hollowed-out area of ​​the conductive member. This reduces the risk of short circuits in the battery cells and improves the reliability of the battery cells. Along the thickness of the current collector, the projection of the first end surface lies within the projection of the first connector. This prevents the edge of the first connector away from the active material layer from being positioned opposite the main functional portion, reducing the risk of short circuits in the battery cells and improving the reliability of the battery cells.

[0070] In some embodiments, the electrode assembly also includes a second pole piece with opposite polarity to the first pole piece, and the second pole piece includes a main functional portion and a pole ear portion arranged along the first direction, the end of the main functional portion close to the transition portion has a first end face, and the pole ear portion extends outward from the first end face; along the thickness direction of the current collector, the projection of the first end face is located within the projection of the first insulating member.

[0071] By adopting the technical solution of this embodiment, the first insulating member can block the pointed protrusion at the first end surface, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0072] In some embodiments, the number of metal layers is two, and the two metal layers cover the opposite sides of the insulating substrate along the thickness direction of the current collector; the number of active material layers is two, and the two active material layers respectively cover the conductive parts of the two metal layers; the number of conductive components is two, and the first connecting parts of the two conductive components are respectively connected to the two metal layers; the number of first insulating parts is two, and the two first insulating parts respectively cover the first connecting sub-parts of the two conductive components.

[0073] By adopting the technical solution of this embodiment, the first connecting parts of the two conductive components are respectively welded to the metal layers located on opposite sides of the insulating substrate, so that the second connecting parts of the two conductive components can be connected, thereby electrically conducting the two metal layers, 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 heating risk of the battery cell, and improving the reliability of the battery cell.

[0074] In some embodiments, along the direction of the conductive portion pointing to the transition portion, the portion of the first insulating member protruding from the first connecting sub-portion forms a blocking portion, and along the second direction, the blocking portion is located on the side of the second connecting portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0075] By adopting the technical solution of this embodiment, the blocking portion can block burrs, metal debris and other components at the edge of the first connecting sub-portion away from the active material layer, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0076] In some embodiments, the blocking portions of the two first insulating members are in contact with each other.

[0077] By adopting the technical solution of this embodiment, after the blocking parts of the two first insulating parts are bonded together, the burrs, metal debris and other components at the edge of the first connecting sub-part away from the active material layer can be wrapped, thereby blocking the burrs at the edge of the first connecting sub-part away from the active material layer, reducing the risk of metal debris falling, reducing the risk of short circuit of the battery cell, and improving the reliability of the battery cell.

[0078] In some embodiments, the second connection portions of the two conductive members are welded to form a second weld mark.

[0079] By adopting the technical solution of this embodiment, the welding of the second connecting parts of the two conductive components can electrically connect the metal layers located on opposite sides of the insulating substrate, thereby breaking the insulation limitations 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 reliability of the battery cell.

[0080] In some embodiments, the first insulating member covers at least a portion of the second weld mark.

[0081] By adopting the technical solution of this embodiment, the first insulating member can cover the second weld mark, blocking the pointed protrusions, metal debris and other components on the second weld mark, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0082] In some embodiments, along a direction from the conductive portion to the transition portion, the first insulating member protrudes beyond an edge of the second weld mark away from the active material layer.

[0083] By adopting the technical solution of this embodiment, the first insulating member can cover the entire second weld mark, blocking burrs, metal debris and other components on the second weld mark, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0084] In some embodiments, the current collector includes a conductive protection layer, at least a portion of which is located between the active material layer and the conductive portion.

[0085] By adopting the technical solution of this embodiment, the conductive protective layer can separate the active material layer and the conductive part, thereby protecting the conductive part and reducing the risk of cracks in the conductive part caused by rolling the active material layer, which is beneficial to improving the electron transmission capacity of the conductive part and improving the fast charging performance of the battery cell.

[0086] In some embodiments, along the direction from the conductive portion to the transition portion, the conductive protection layer protrudes from the end portion of the active material layer close to the first connecting sub-portion.

[0087] By adopting the technical solution of this embodiment, the conductive protective layer can completely separate the active material layer and the metal layer, the conductive protective layer has better protection capability for the metal layer, and the first electrode has better current carrying capacity, which is beneficial to improving the fast charging performance and use reliability of the battery cell.

[0088] In some embodiments, along the direction from the conductive portion to the transition portion, the conductive protection layer protrudes from the active material layer by a length ranging from 0.3 mm to 0.8 mm.

[0089] By adopting the technical solution of this embodiment, the current capacity and energy density of the battery cell can be better taken into account.

[0090] In some embodiments, the first connecting portion is welded to the surface of the metal layer facing away from the insulating substrate to form a first weld mark, and along the first direction, the conductive protective layer and the first weld mark are spaced apart.

[0091] 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 risk of cold welding between the first connecting portion and the metal layer, and is conducive to improving the reliability of welding between the first connecting portion and the metal layer.

[0092] In some embodiments, the first insulating member is connected to the first pole piece.

[0093] By adopting the technical solution of this embodiment, the first insulating member is connected to the first pole piece, and the first insulating member can be fixed, thereby stably blocking the first connecting sub-part from burrs, metal debris and other components at the edge of the active material layer, which is beneficial to improving the reliability of the battery cell.

[0094] In some embodiments, the first insulating member 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.

[0095] By adopting the technical solution of this embodiment, the first insulating member adopts the structural form of tape, and the first insulating member can be directly adhered to the first pole piece, reducing the risk of leakage coverage; the insulating base layer and the adhesive layer cover the first pole piece to block the burrs on the first pole piece, and the thickness of the insulating base layer and the adhesive layer do not need to be set large, which is beneficial to improving the energy density of the battery cell; the insulating base layer has good structural strength, which can stably block the burrs on the first pole piece and improve the reliability of the battery cell; the adhesive layer can stably fix the insulating base layer on the first pole piece, reducing the risk of the first insulating member falling off; metal debris on the first pole piece can also be adhered to the adhesive layer, which can effectively reduce the risk of metal debris on the first pole piece falling off and reduce the short circuit risk of the battery cell.

[0096] In some embodiments, the thickness of the insulating base layer is in a range of 6 μm to 15 μm; and / or the thickness of the adhesive layer is in a range of 0.5 μm to 3 μm.

[0097] By adopting the technical solution of this embodiment, both the internal insulation and energy density of the battery cell can be taken into consideration.

[0098] In some embodiments, along the first direction, the first insulating member has a dimension W, wherein 3 mm ≤ W ≤ 9 mm, optionally, 4.5 mm ≤ W ≤ 6.5 mm.

[0099] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell can be taken into account.

[0100] In some embodiments, at least a portion of the conductive portion has a thickness smaller than a thickness of the transition portion.

[0101] By adopting the technical solution of this embodiment, the thickness of the transition part can be greater than the thickness of at least part of the conductive part. The large thickness of the transition part improves the current flow capacity of the transition part, reduces the heat generation of the transition part, reduces the melting risk of the first insulating part, and improves the reliability of the battery cell. In addition, it also improves the current flow capacity of the transition part, which is also conducive to improving the fast charging performance of the battery cell.

[0102] In some embodiments, the conductive portion includes a first sub-portion and a second sub-portion, the first sub-portion is connected between the second sub-portion and the transition portion, the first sub-portion and the second sub-portion are covered with an active material layer, the thickness of the first sub-portion is greater than the thickness of the second sub-portion, and the thickness of the transition portion is greater than or equal to the thickness of the first sub-portion.

[0103] By adopting the technical solution of this embodiment, the thickness of the first sub-section is greater than the thickness of the second sub-section, so that the current flow capacity of the first sub-section is greater than the current flow capacity of the second sub-section. This can reduce the restriction on current, improve the current flow capacity of the first electrode, reduce the heat generation of the battery cell, and help improve the reliability of the battery cell.

[0104] In some embodiments, the current collector also 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.

[0105] By adopting the technical solution of this embodiment, the surface of the conductive protective layer facing away from the insulating substrate is close to a plane, which is beneficial to reducing rolling damage and improving the current carrying capacity of the metal layer; in addition, it can also reduce the winding bulging problem of the current collector.

[0106] In some embodiments, the conductive protection layer further includes a third protection portion, the third protection portion covers a surface of the transition portion facing away from the insulating substrate, and a thickness of the third protection portion is less than or equal to a thickness of the first protection portion.

[0107] By adopting the technical solution of this embodiment, the provision of the third protective portion can make the conductive protective layer protrude from the active material layer, so that the active material layer and the metal layer can be better separated. In addition, the thickness of the third protective portion is not too large, which is beneficial to reduce material waste and save the production cost of battery cells.

[0108] In some embodiments, the metal layer further includes at least one protrusion, and the transition portion is connected between the protrusion and the conductive portion; along the second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the transition portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; the thickness of the protrusion is greater than or equal to the thickness of the transition portion.

[0109] By adopting the technical solution of this embodiment, the thickness of the protrusion is larger, which can improve the current flow capacity of the protrusion, which is beneficial to improving the current flow capacity of the first pole piece, reducing the heat generation of the battery cell, and improving the fast charging performance and use reliability of the battery cell.

[0110] In a second aspect, in some embodiments, a battery device includes the battery cell of the above embodiment.

[0111] The battery device of the embodiment of the present application adopts the above-mentioned battery cell, and the battery cell has good reliability in use, and the battery device has good reliability in use.

[0112] In a third aspect, in some embodiments, the electrical device includes a battery device as described in the above embodiments.

[0113] The electrical device of the embodiment of the present application adopts the above-mentioned battery device, which has good reliability in use and is conducive to improving the reliability of the electrical device.

[0114] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0115] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0116] Figure 1 A schematic structural diagram of a vehicle provided for some embodiments of the present application.

[0117] Figure 2 A schematic structural diagram of a battery device provided in some embodiments of the present application.

[0118] Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application.

[0119] Figure 4A schematic structural diagram of the electrode assembly provided in some embodiments of the present application.

[0120] Figure 5 For the Figure 4 Sectional view along line AA.

[0121] Figure 6 Schematic diagram of the structure of the first pole piece, the first insulating member and the second insulating member provided in some embodiments of the present application.

[0122] Figure 7 For the Figure 6 Sectional view along the midline BB.

[0123] Figure 8 Schematic diagram of the structure of the first pole piece and the second insulating member provided in some embodiments of the present application.

[0124] Figure 9 for Figure 8 A partial enlarged view of point D in the middle.

[0125] Figure 10 A schematic diagram of the structure of the first pole piece after hiding the conductive component provided in some embodiments of the present application.

[0126] Figure 11 for Figure 10 A partial enlarged view of point E in the middle.

[0127] Figure 12 For the Figure 6 Sectional view of the midline CC.

[0128] Figure 13 The first pole piece, the first insulating member and the second insulating member provided in other embodiments of the present application are Figure 6 Sectional view along the midline BB.

[0129] Figure 14 A schematic structural diagram of the first insulating member provided in some embodiments of the present application.

[0130] Figure 15 For the Figure 14 Sectional view along the midline FF.

[0131] Among them, the reference numerals in the figures are:

[0132] 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; 1211, conductive part; 12111, first sub-part; 12112, second sub-part; 1212, transition part; 122, protrusion; 13, conductive protective layer; 131, first protective part; 132, second protective part; 133, third protective part; 20, active material layer; 30, conductive member; 31, first connecting part; 311, first connecting sub-part; 312, first connecting sub-part; Second connecting sub-part; 32, second connecting part; 41, first insulating member; 4111, insulating base layer; 4112, adhesive layer; 4121, first insulating part; 4122, second insulating part; 4131, blocking part; 42, second insulating member; 51, first weld mark; 511, first weld mark part; 512, second weld mark part; 52, second weld mark; 2, second pole piece; 210, main functional part; 2101, first end face; 220, pole ear part; 3, isolating member; 200, outer shell; 201, end cover; 2011, electrode lead-out part; 202, shell; 300, box body; 301, first box body part; 302, second box body part. DETAILED DESCRIPTION

[0133] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0134] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0135] In the description of the embodiments of this application, the technical terms "first," "second," etc., are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance, or to implicitly specify the quantity, specific order, or primary-secondary relationship of the technical features indicated. Therefore, a feature designated "first" or "second" may explicitly or implicitly include one or more of such features.

[0136] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least some embodiments of the present application. The appearance of such phrases in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments in any suitable manner.

[0137] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0138] In the description of the embodiments of this application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more (including two groups), and "multiple sheets" refers to two or more (including two sheets). "Several" means one or more, unless otherwise specifically defined.

[0139] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0140] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0141] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, when an element is referred to as being “fixed to” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0142] Battery cells may include but are 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-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0143] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell or a battery cell of another shape. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery cell, such as a hexagonal battery cell.

[0144] 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.

[0145] In some embodiments, the battery device may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0146] In some embodiments, the battery device may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0147] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0148] In some embodiments, the battery device may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0149] A battery cell typically consists of an electrode assembly and a housing. The electrode assembly is housed within 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 inserted and removed back and forth between the positive and negative electrodes.

[0150] In some embodiments, the electrode assembly further includes a separator, which is disposed between the positive electrode and the negative electrode to prevent a short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0151] The housing is used to encapsulate the electrode assembly and electrolyte components. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film.

[0152] In some embodiments, the positive electrode may be a positive electrode sheet, which may 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 may be a negative electrode sheet, which may 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.

[0153] Current collectors (positive or negative) are typically made of metal, such as aluminum foil or copper foil. However, pure metal foil is prone to burrs, which can penetrate the separator and cause internal short circuits, posing a significant risk of fire and explosion in battery cells.

[0154] In order to reduce the risk of short circuit in battery cells, a current collector is proposed, which includes an insulating substrate and a metal layer covering the surface of the insulating substrate, and an active material layer covering the surface of the metal layer facing away from the insulating substrate. Compared with pure metal, the metal layer has a smaller thickness, and the burrs generated after the metal layer is cut are smaller, and it is not easy to pierce the diaphragm, thereby reducing the short circuit risk of the battery cell; the edge of the metal layer is usually connected to a conductive component, and the conductive component includes a first connecting part and a second connecting part connected to each other, the first connecting part is connected to the metal layer, and the second connecting part is electrically connected to the electrode lead-out part, thereby realizing the input or output of electrical energy of the battery cell; but during the use of the battery cell, the first connecting part includes a first connecting sub-part, and the first connecting sub-part covers the edge of the main body of the metal layer. The edge of the first connecting sub-part away from the active material layer is prone to burrs during the manufacturing process, thereby increasing the short circuit risk of the battery cell, which is not conducive to improving the reliability of the battery cell.

[0155] Based on this, an embodiment of the present application provides a technical solution, in which the conductive component of the battery cell includes a first connecting part and at least one second connecting part connected to each other, the first connecting part includes a first connecting sub-part, and the first connecting sub-part is covered on the transition part of the main part of the metal layer. The battery cell also includes a first insulating part, and the first insulating part is covered on the first connecting sub-part, and along the direction of the conductive part pointing to the transition part, the first insulating part protrudes from the edge of the first connecting sub-part away from the active material layer, so that the first insulating part can block the burrs at the edge of the first connecting sub-part away from the active material layer, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0156] The battery cells described in the embodiments of the present application are applicable to battery devices and electrical devices using the battery devices.

[0157] The battery device disclosed in the embodiments of the present application can be used in various energy storage systems that use the battery device as a power source or use the battery device as an energy storage element. The power device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like, and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0158] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0159] like Figure 1 As shown, a battery device 1100 is provided inside the vehicle 1000, and 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 power the vehicle 1000, for example, the battery device 1100 can serve as an operating power source for the vehicle 1000.

[0160] 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, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0161] In some embodiments of the present application, the battery device 1100 can not only serve as the operating power source of the vehicle 1000, but also serve 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 Schematic diagram of an explosion of a battery device 1100 provided in some embodiments of the present application. Figure 2 As shown, the battery device 1100 includes a housing 300 and battery cells, wherein the battery cells are accommodated in the housing 300 .

[0162] The housing 300 is used to house battery cells and 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 overlap each other, and the first housing portion 301 and the second housing portion 302 together define a storage space for accommodating the battery cells. The second housing portion 302 can be a hollow structure with one end open. The first housing portion 301 is a plate-like structure, and the first housing portion 301 overlaps the open side of the second housing portion 302 to form the housing 300 with a storage space. The first housing portion 301 and the second housing portion 302 can also each be a hollow structure with one end open. The open side of the first housing portion 301 overlaps the open side of the second housing portion 302 to form the housing 300 with a storage space. Of course, the first housing portion 301 and the second housing portion 302 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0163] In order to improve the sealing performance after the first box body 301 and the second box body 302 are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 301 and the second box body 302 .

[0164] Assuming that the first box portion 301 covers the top of the second box portion 302 , the first box portion 301 can also be referred to as an upper box cover, and the second box portion 302 can also be referred to as a lower box 300 .

[0165] In the battery device 1100 , there can be one or more battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in a mixed connection. Mixed connection means that the multiple battery cells are connected in both series and parallel.

[0166] Multiple battery cells can be directly connected in series, in parallel, or mixed together, and then the whole formed by the multiple battery cells can be accommodated in the box 300; of course, multiple battery cells can also be first connected in series, in parallel, or mixed together to form a battery module, and then the multiple battery modules can be connected in series, in parallel, or mixed together to form a whole and accommodated in the box 300.

[0167] For example, a battery cell may be the smallest unit constituting the battery device 1100 .

[0168] like Figure 3 As shown, in some embodiments, a battery cell includes a housing 200 and an electrode assembly 101 housed 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 also 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 while allowing active ions to pass through.

[0169] The housing 200 is used to encapsulate the electrode assembly 101 and components such as the electrolyte.

[0170] In some embodiments, the housing 200 includes a shell 202 and an end cover 201 . The shell 202 has an opening, and the end cover 201 is used to cover the opening.

[0171] The housing 202 is a component used to cooperate with the end cap 201 to form an internal cavity of the battery cell. The formed internal cavity can be used to accommodate the electrode assembly 101, electrolyte and other components.

[0172] The housing 202 and the end cap 201 may be separate components. For example, an opening may be provided on the housing 202, and the end cap 201 may be placed over the opening to form an internal cavity of the battery cell.

[0173] The housing 202 can have various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 202 can be determined based on the specific shape and size of the electrode assembly 101. The housing 202 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0174] The shape of the end cap 201 can be adapted to the shape of the housing 202 to fit 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 a certain hardness and strength (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 201 is less likely to deform when subjected to compression or collision, thereby providing the battery cell with higher structural strength and improved reliability.

[0175] The end cover 201 is connected to the housing 202 by welding, bonding, clamping or other methods.

[0176] The housing 202 may be open at one end or at both ends. In some examples, the housing 202 may be open at one end, with one end cap 201 provided to cover the housing 202. In other examples, the housing 202 may be open at both ends, with two end caps 201 provided to cover the two openings of the housing 202, respectively.

[0177] In some embodiments, the battery cell includes two electrode lead-out portions 2011. The two electrode lead-out portions 2011 are connected to the positive electrode sheet and the negative electrode sheet, respectively, for outputting or inputting electrical energy of the battery cell.

[0178] In some embodiments, the battery cell further includes an electrolyte contained within the housing 200. The electrolyte serves to conduct ions between the positive and negative electrodes and can be in liquid, gel, or solid form.

[0179] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0180] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0181] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0182] The solvent may also be an ether solvent, which 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.

[0183] In some embodiments, the gel electrolyte includes a polymer as an electrolyte skeleton network and an ionic liquid-lithium salt.

[0184] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, or a composite solid electrolyte.

[0185] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0186] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0187] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0188] Reference Figure 4 and Figure 5 The electrode assembly 101 of the embodiment of the present application includes a first electrode piece 1 and a second electrode piece 2 with opposite polarities.

[0189] Exemplarily, one of the first electrode sheet 1 and the second electrode sheet 2 is a positive electrode sheet, and the other is a negative electrode sheet.

[0190] In some embodiments, the positive electrode sheet may 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.

[0191] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0192] As an example, the positive electrode current collector may be made of carbon, metal foil, or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, aluminum or stainless steel with a nickel, titanium, or silver surface treatment may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0193] 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 may also use other traditional materials that can be used as the positive electrode active material layer of the battery device 1100. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. 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 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3O2 (also referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to 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.).

[0194] In some embodiments, the negative electrode sheet may 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.

[0195] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (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.).

[0196] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may be a negative electrode active material for a battery cell that is well known in the art. 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, lithium titanate, etc. The silicon-based material may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may include at least one of elemental tin, tin oxide compounds, and tin alloys. The negative electrode active material of the present application may also use other traditional materials that can be used as negative electrode active materials of the battery device 1100. These negative electrode active materials may be used alone or in combination of two or more.

[0197] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0198] In some embodiments, the electrode assembly 101 further includes a separator 3, which is used to separate the first electrode 1 from the second electrode 2. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0199] In some embodiments, the separator 3 includes an isolation membrane. The isolation membrane of the present application can be any known porous structure isolation membrane with good chemical stability and mechanical stability.

[0200] As an example, the primary material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator 3 may be a separate component positioned between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0201] 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 serves to transmit ions and isolate the positive and negative electrodes.

[0202] In some embodiments, the electrode assembly 101 is a wound structure. For example, the first electrode sheet 1 and the second electrode sheet 2 are both strip-shaped structures, and the first electrode sheet 1, the separator 3 and the second electrode sheet 2 are wound into a wound structure.

[0203] In some embodiments, the electrode assembly 101 is a laminated structure.

[0204] As an example, a plurality of first pole pieces 1 and a plurality of second pole pieces 2 may be provided respectively, and the plurality of first pole pieces 1 and the plurality of second pole pieces 2 may be alternately stacked.

[0205] As an example, a plurality of first pole pieces 1 may be provided, and the second pole piece 2 may be folded to form a plurality of stacked folded segments, with one first pole piece 1 being sandwiched between adjacent folded segments.

[0206] As an example, the first pole piece 1 and the second pole piece 2 are both folded to form a plurality of stacked folded segments.

[0207] As an example, a plurality of spacers 3 may be provided, each spacer 3 being provided between any adjacent first pole pieces 1 or second pole pieces 2 .

[0208] As an example, the spacer 3 may be provided continuously, and may be provided between any adjacent first pole pieces 1 or second pole pieces 2 by folding or winding.

[0209] In some embodiments, the shape of the electrode assembly 101 can be cylindrical, flat, or polygonal.

[0210] like Figures 6-11As shown, in some embodiments, the battery cell 100 includes a shell 200 and an electrode assembly 101; the shell 200 is provided with an electrode lead-out portion 2011; at least a portion of the electrode assembly 101 is accommodated in the shell 200, the electrode assembly 101 includes a first pole piece 1 and a first insulating member 41, the first pole piece 1 includes a conductive member 30, a current collector 10 and an active material layer 20, the current collector 10 includes an insulating base 11 and a metal layer 12; the insulating base 11, the metal layer 12 and the active material layer 20 are stacked along the thickness direction of the current collector 10, and at least a portion of the metal layer 12 is located between the insulating base 11 and the active material layer 20; the metal layer 12 includes a main body 121, and the main body 121 includes a transition portion arranged and connected along the first direction. The conductive portion 1212 and the conductive portion 1211 have a first direction perpendicular to the thickness direction of the current collector 10; at least a portion of the conductive portion 1211 is covered with the active material layer 20, and the transition portion 1212 is not covered with the active material layer 20; the conductive member 30 includes a first connecting portion 31 and at least one second connecting portion 32 connected to each other, the first connecting portion 31 is connected to the metal layer 12, and the second connecting portion 32 is electrically connected to the electrode lead-out portion 2011, the first connecting portion 31 includes a first connecting sub-portion 311, and the first connecting sub-portion 311 is covered on the surface of the transition portion 1212 facing away from the insulating substrate 11; along the direction of the conductive portion 1211 pointing to the transition portion 1212, the first insulating member 41 protrudes from the first connecting sub-portion 311 away from the edge of the active material layer 20.

[0211] A portion of the electrode assembly 101 is located inside the housing 200 , and another portion is located outside the housing 200 ; alternatively, the entire electrode assembly 101 is located inside the housing 200 .

[0212] In some examples, the first electrode sheet 1 is a positive electrode sheet, the current collector 10 is a positive electrode current collector, the positive electrode current collector adopts a composite current collector 10 structure, and the active material layer 20 is a positive electrode active material layer 20; or, the first electrode sheet 1 is a negative electrode sheet, the current collector 10 is a negative electrode current collector, the negative electrode current collector has a composite current collector 10 structure, and the active material layer 20 is a negative electrode active material layer 20.

[0213] 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 may refer to a component in the current collector 10 made of insulating material (for example, the above-mentioned polymer substrate), and the metal layer 12 may refer to a component in the current collector 10 made of the above-mentioned metal material.

[0214] 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 Figure 7The active material layer 20 may be directly covered on the surface of the metal layer 12, or the surface of the metal layer 12 may be covered with other materials (eg, the conductive protective layer 13) and then covered with the active material layer 20.

[0215] In some examples, a surface of the insulating substrate 11 is covered with a metal layer 12 .

[0216] In some examples, two opposite surfaces of the insulating substrate 11 are covered with metal layers 12 . Among the two metal layers 12 , a surface of at least one metal layer 12 facing away from the insulating substrate 11 is covered with an active material layer 20 .

[0217] The metal layer 12 includes a main body portion 121 , which may refer to a main part of the metal layer 12 .

[0218] In some examples, the metal layer 12 may be a structure with a uniform width, and the metal layer 12 is the main body 121 .

[0219] In some examples, the edge of the metal layer 12 has a protruding structure (eg, protruding portion 122), and the rest of the metal layer 12 except the protruding structure constitutes the main body 121. Of course, in other examples, other structures are also possible.

[0220] In some examples, along the first direction, the main body 121 is divided into two parts, the part covered with the active material layer 20 is the conductive part 1211, and the part not covered with the active material layer 20 is the transition part 1212; the interface between the conductive part 1211 and the transition part 1212 can refer to the end surface of the active material layer 20 close to the transition part 1212 (see Figure 7 The end portion of the active material layer 20 near the transition portion 1212 may be thinned to reduce the roller pressure applied to the end portion of the active material layer 20 near the transition portion 1212 during rolling of the active material layer 20, thereby reducing damage to the metal layer 12. The end surface of the active material layer 20 near the transition portion 1212 may be a plane or may be approximately a straight line.

[0221] In some examples, the conductive portion 1211 has a uniform width, and the transition portion 1212 may have a uniform width as the conductive portion 1211 .

[0222] The first direction may refer to a direction perpendicular to the thickness direction of the current collector 10, or a direction close to perpendicular to the current collector 10; the second direction may refer to a direction perpendicular to the thickness direction of the current collector 10 and the first direction, or a direction close to perpendicular to the thickness direction of the current collector 10 and the first direction.

[0223] In some examples, the electrode assembly 101 is a wound structure. When the first electrode sheet 1 is in an unfolded state, the first direction can refer to the width direction of the first electrode sheet 1 (refer to Figure 6 The second direction can refer to the length direction of the first pole piece 1 (see Figure 6 When the first pole piece 1 is in the winding state, the second direction can also refer to the winding direction of the first pole piece 1 (see Figure 4 direction indicated by arrow V).

[0224] In some examples, the electrode assembly 101 is a laminated structure, and the first direction may be the width direction of the first electrode 1 (see Figure 6 The second direction can refer to the length direction of the first pole piece 1 (see Figure 6 The direction of the conductive portion 1211 pointing to the transition portion 1212 can be referred to in Figure 7 The positive direction of the Z direction; the direction of the transition portion 1212 pointing to the conductive portion 1211 can be referred to Figure 7 The negative Z direction.

[0225] The conductive member 30 may refer to a component used to connect the electrode lead portion 2011 and the metal layer 12 . The conductive member 30 may be made of copper foil or aluminum foil to improve the current carrying capacity of the conductive member 30 .

[0226] The electrode lead-out portion 2011 may refer to a metal component used to output or input electrical energy. The electrode lead-out portion 2011 is connected to an external electronic device so that the battery cell 100 outputs or inputs electrical energy. The electrode lead-out portion 2011 may also be called a pole. The electrode lead-out portion 2011 may be provided on the shell 202 or on the end cover 201.

[0227] The conductive member 30 includes a first connecting portion 31 and at least one second connecting portion 32. The first connecting portion 31 may be the portion connecting the conductive member 30 to the metal layer 12, and the second connecting portion 32 may be the portion connecting the conductive member 30 to the electrode lead portion 2011. The first connecting portion 31 includes a first connecting sub-portion 311. The first connecting sub-portion 311 may be the portion of the first connecting portion 311 that covers the surface of the transition portion 1212 facing away from the insulating substrate 11. The first connecting sub-portion 311 may cover a portion of the transition portion 1212 or the entire transition portion 1212.

[0228] In some examples, the second connecting portion 32 can extend directly from the side of the first connecting portion 31 facing away from the active material layer 20 along the first direction and away from the active material layer 20, so that the second connecting portion 32 protrudes out of the insulating base 11, that is, along the thickness direction of the current collector 10, the projection of the first connecting portion 31 is located within the projection of the metal layer 12, the projection of the second connecting portion 32 is located outside the projection range of the metal layer 12, and the projection of the first connecting sub-portion 311 is located within the projection range of the transition portion 1212; the connection positions of the metal layer 12 and the electrode lead portion 2011 on the conductive component 30 are different, the connection is convenient, and the mutual influence between the connections between the two can also be reduced, which is beneficial to the connection reliability.

[0229] In some examples, the second connection portion 32 and the electrode lead portion 2011 can be electrically connected by direct welding, or by welding through a conductive member (e.g., an adapter plate, etc.). Welding is convenient for connection and manufacturing. Of course, other methods can also be used to achieve electrical connection.

[0230] In some examples, when the electrode sheet is wound to form the electrode assembly 101, the insulating substrate 11 insulates and separates the two adjacent layers of the metal layer 12, resulting in that it is not easy for the two adjacent layers of the metal layer 12 to directly connect across the insulating substrate 11 and pass current outward, so that the current can almost only be transmitted outward from the outermost layer of the metal layer 12, resulting in poor conductivity and low fast charging performance, and easily causing local overheating, affecting the reliability of the battery cell 100; the battery cell 100 of the embodiment of the present application can use the second connecting portion 32 to electrically connect the two adjacent layers of the metal layer 12, thereby breaking the insulation limitation of the insulating substrate 11, which can effectively improve the conductivity of the first electrode sheet 1, improve the fast charging performance of the battery cell 100, reduce the heat generation of the battery cell 100, and improve the reliability of the battery cell 100.

[0231] In some examples, when the pole pieces are stacked to form the electrode assembly 101, the insulating matrix 11 insulates and separates two adjacent metal layers 12, making it difficult for the two adjacent metal layers 12 to directly connect across the insulating matrix 11 and transmit current outward. As a result, current can almost only be transmitted outward through the outermost metal layer 12, resulting in poor conductivity, low fast-charging performance, and easy local overheating, affecting the reliability of the battery cell 100. The battery cell 100 of the embodiment of the present application can use the second connecting portion 32 to electrically connect the two adjacent metal layers 12, 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 reliability of the battery cell 100.

[0232] The first insulating member 41 is made of insulating material, such as PP (polypropylene), PET (polyethylene terephthalate), etc. The first insulating member 41 can be, but is not limited to, an insulating coating, an insulating adhesive (such as hot melt adhesive), or an insulating tape.

[0233] In some examples, the first insulating member 41 can be fixed to the first connecting sub-portion 311 by adhesion or static adsorption.

[0234] In some examples, along the direction from the conductive portion 1211 to the transition portion 1212, the first insulating member 41 protrudes beyond the edge of the first connecting sub-portion 311 away from the active material layer 20. Of the two side surfaces of the first connecting sub-portion 311 opposite each other along the first direction, the side surface away from the active material layer 20 may be the edge of the first connecting sub-portion 311 away from the active material layer 20. Along the thickness direction of the current collector 10, the projection of the edge of the first connecting sub-portion 311 away from the active material layer 20 is located within the projection of the first insulating member 41.

[0235] By adopting the technical solution of this embodiment, the first insulating member 41 can block the burrs at the edge of the first connecting sub-portion 311 away from the active material layer 20, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100; in addition, the current collector 10 adopts a composite structure of an insulating substrate 11 and a metal layer 12. Compared with the pure metal current collector 10, the thickness of the metal layer 12 is small, and the burrs generated by the current collector 10 during the manufacturing process are smaller, which reduces the internal short circuit risk of the battery cell 100 and is conducive to improving the reliability of the battery cell 100.

[0236] During the use of some battery cells 100, the edge of the first connecting sub-portion 311 away from the active material layer 20 may be impacted, thereby generating metal debris. The metal debris falls between the first pole piece 1 and the second pole piece 2, increasing the short circuit risk of the battery cell 100 and reducing the reliability of the battery cell 100. However, in the battery cell 100 of the embodiment of the present application, the first insulating member 41 can block the metal debris, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0237] In some embodiments, see Figure 6 and Figure 7 As shown, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes from the edge of the first connecting sub-portion 311 close to the active material layer 20 .

[0238] In some examples, of the two side surfaces of the first connecting sub-portion 311 that are opposite to each other along the first direction, the side surface close to the active material layer 20 may refer to an edge of the first connecting sub-portion 311 close to the active material layer 20. Along the thickness direction of the current collector 10, the projection of the edge of the first connecting sub-portion 311 close to the active material layer 20 is located within the projection of the first insulating member 41.

[0239] In some examples, along the first direction, opposite sides of the first insulating member 41 protrude from opposite edges of the first connecting sub-portion 311 respectively; along the thickness direction of the current collector 10, the projection of the first connecting sub-portion 311 is located within the projection of the first insulating member 41, so that the first insulating member 41 can cover the entire first connecting sub-portion 311, thereby achieving insulation of the entire first connecting sub-portion 311.

[0240] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the edge of the first connecting sub-portion 311 close to the active material layer 20, thereby blocking the burrs at the edge of the first connecting sub-portion 311 close to the active material layer 20, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100; in addition, the first insulating member 41 can cover the entire first connecting sub-portion 311 to achieve overall insulation of the first connecting sub-portion 311, which can effectively reduce the short circuit of the battery cell 100 and improve the reliability of the battery cell 100.

[0241] In some embodiments, see Figure 12 As shown, along the first direction, the edge of the transition portion 1212 away from the conductive portion 1211 is flush with the edge of the first connecting sub-portion 311 away from the active material layer 20 .

[0242] In some examples, among the two side surfaces of the transition portion 1212 that are opposite to each other along the first direction, the side surface away from the conductive portion 1211 may refer to an edge of the transition portion 1212 away from the conductive portion 1211 .

[0243] Along the thickness direction of the current collector 10, the projection of the edge of the transition portion 1212 away from the active material layer 20 coincides with the edge of the first connecting sub-portion 311 away from the active material layer 20, so that the side of the first connecting sub-portion 311 away from the active material layer 20 is flush with the side of the transition portion 1212 away from the active material layer 20.

[0244] During the production process of some first pole pieces 1, the conductive component 30 is connected to the metal layer 12 of the current collector 10, and the conductive component 30 and the current collector 10 are cut to obtain the transition portion 1212 and the first connecting sub-portion 311. The side of the transition portion 1212 away from the active material layer 20 and the side of the first connecting sub-portion 311 away from the active material layer 20 are obtained by cutting at the same time, so that the side of the first connecting sub-portion 311 away from the active material layer 20 is flush with the side of the transition portion 1212 away from the active material layer 20.

[0245] By adopting the technical solution of this embodiment, along the first direction, the edge of the transition portion 1212 away from the conductive portion 1211 is flush with the edge of the first connecting sub-portion 311 away from the active material layer 20, the structure of the first pole piece 1 is regular, and processing and manufacturing are convenient, and the redundancy of the first connecting sub-portion 311 or the transition portion 1212 can be reduced, thereby saving space and improving the energy density of the battery cell 100; in addition, the first insulating member 41 also protrudes from the edge of the transition portion 1212 away from the active material layer 20, blocking burrs, metal debris and other components at the edge of the transition portion 1212 away from the active material layer 20, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0246] In some embodiments, see Figure 8 As shown, along the second direction, the size of the conductive portion 1211 is L1, the size of the transition portion 1212 is L2, 0.8≤L2 / L1≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0247] 0.8≤L2 / L1≤1, along the second direction, the size of the transition portion 1212 is less than or equal to the size of the conductive portion 1211, and the size of the transition portion 1212 is greater than or equal to 0.8 times the size of the conductive portion 1211, so that the size of the transition portion 1212 is not much different from or equal to the size of the conductive portion 1211, wherein, the larger the size of the transition portion 1212, the larger the connection area between the transition portion 1212 and the first connecting sub-portion 311 can be set, and the better the current flow capacity between the transition portion 1212 and the first connecting sub-portion 311.

[0248] The value of L2 / L1 may be, but is not limited to, 0.8, 1, or any value between 0.8 and 1. For example, the value of L2 / L1 may be, but is not limited to, 0.8, 0.85, 0.9, 0.95, or 1.

[0249] In some examples, 0.8≤L2 / L1<1, and along the second direction, the transition portion 1212 may be located in the middle of the conductive portion 1211 , and both ends of the transition portion 1212 are not flush with the conductive portion 1211 .

[0250] In some examples, 0.8≤L2 / L1<1, and along the second direction, the transition portion 1212 is arranged with one end of the conductive portion 1211, which may also be biased toward the conductive portion 1211, so that one end of the transition portion 1212 is flush with the conductive portion 1211 and the other end is not flush, or both ends are not flush.

[0251] In some examples, L2=L1, in the second direction, the size of the transition portion 1212 is equal to the size of the conductive portion 1211, and in the second direction, both ends of the transition portion 1212 are flush with the conductive portion 1211, and the transition portion 1212 and the conductive portion 1211 are equal length structures.

[0252] By adopting the technical solution of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition portion 1212 along the second direction large, which is beneficial to increasing the connection area between the first connecting sub-portion 311 and the transition portion 1212, improving the flow capacity between the first connecting sub-portion 311 and the transition portion 1212, improving the flow 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 100.

[0253] In some embodiments, see Figures 7-9 As shown, 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 weld mark 51 . Along the first direction, the first weld mark 51 is located on the side of the active material layer 20 close to the transition portion 1212 .

[0254] The first connecting portion 31 is welded to the side of the metal layer 12 located near the transition portion 1212 of the active material layer 20. The weld mark formed by the welding is the first weld mark 51. The first weld mark 51 can be a single piece or a combination of multiple weld marks. The first connecting sub-portion 311 can be welded to the transition portion 1212 or not.

[0255] By adopting the technical solution of this embodiment, the first connection portion 31 is welded to the metal layer 12, the welding operation is simple, and the production and processing of the first electrode 1 are convenient; the first weld mark 51 is located on the side of the active material layer 20 close to the transition portion 1212, so that the first weld mark 51 is separated from the active material layer 20, reducing the risk of cold welding between the first connection portion 31 and the metal layer 12 due to the active material layer 20, which is beneficial to improving the reliability of the battery cell 100.

[0256] In some embodiments, see Figure 7 As shown, the first insulating member 41 covers at least a portion of the first weld mark 51 .

[0257] The first insulating member 41 may cover a portion of the first weld mark 51 or may cover the entire first weld mark 51 .

[0258] By adopting the technical solution of this embodiment, the first insulating member 41 can block burrs, metal debris and other components on the first weld mark 51, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0259] In some embodiments, see Figures 7-9 As shown, the first weld mark 51 includes a first weld mark portion 511 , and the first connecting sub-portion 311 is welded to the surface of the transition portion 1212 facing away from the insulating base 11 to form the first weld mark portion 511 .

[0260] The first connecting sub-portion 311 is welded to the surface of the transition portion 1212 facing away from the insulating base 11 , and a weld mark formed by the welding is a first weld mark portion 511 .

[0261] By adopting the technical solution of this embodiment, the first connecting sub-part 311 is welded to the transition part 1212, so that the current can flow directly to the conductive component 30 through the transition part 1212, which is beneficial to improving the current flow capacity of the first pole piece 1 and improving the fast charging performance of the battery cell 100.

[0262] In some embodiments, see Figure 8 As shown, along the second direction, the size of the transition portion 1212 is L2, the size of the first weld print portion 511 is L3, 0.8≤L3 / L2≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0263] 0.8≤L3 / L2≤1. Along the second direction, the size L3 of the first weld mark 511 may be less than or equal to the size L2 of the transition portion 1212. The size L3 of the first weld mark 511 is greater than or equal to 0.8 times the size L2 of the transition portion 1212. The size L3 of the first weld mark 511 exceeds more than half of the size L2 of the transition portion 1212. The longer the size L3 of the first weld mark 511, the larger the welding area between the transition portion 1212 and the first connecting sub-portion 311, and the better the flow capacity of the connection between the transition portion 1212 and the first connecting sub-portion 311.

[0264] In some examples, 0.8≤L3 / L2<1, along the second direction, the first weld print 511 may be located in the middle of the transition portion 1212 , and opposite edges of the first weld print 511 are not flush with opposite side surfaces of the transition portion 1212 .

[0265] In some examples, 0.8≤L3 / L2<1, and along the second direction, the first weld print 511 is arranged at one end that may also be biased toward the transition portion 1212, so that one edge of the first weld print 511 is flush with one side surface of the transition portion 1212, and the other edge of the first weld print 511 is not flush with the other side surface of the transition portion 1212.

[0266] In some examples, L3 = L2 , and along the second direction, the dimension L3 of the first weld print 511 is equal to the dimension L2 of the transition portion 1212 , and opposite edges of the first weld print 511 are flush with opposite side surfaces of the transition portion 1212 .

[0267] The value of L3 / L2 may be, but is not limited to, 0.8, 1, or any value between 0.8 and 1. For example, the value of L3 / L2 may be, but is not limited to, 0.8, 0.85, 0.9, 0.95, or 1.

[0268] By adopting the technical solution of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the first weld portion 511 along the second direction larger, which is beneficial to increasing the connection area between the first connecting sub-portion 311 and the transition portion 1212, improving the flow capacity at the connection between the first connecting sub-portion 311 and the transition portion 1212, improving the flow 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 100.

[0269] In some embodiments, see Figure 7 As shown, the first insulating member 41 covers at least a portion of the first weld print 511 .

[0270] In some examples, the first insulating member 41 covers a portion of the first weld print 511 . For example, along the thickness direction of the current collector 10 , the projection of the first insulating member 41 partially overlaps with the projection of the first weld print 511 .

[0271] In some examples, the first insulating member 41 covers the entire first weld print 511 . For example, along the thickness direction of the current collector 10 , the projection of the first weld print 511 falls within the projection range of the first insulating member 41 .

[0272] By adopting the technical solution of this embodiment, the first insulating member 41 can block burrs, metal debris and other components on the first weld print portion 511 , thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100 .

[0273] In some embodiments, see Figures 6-9 As shown, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes from the first weld mark 511 close to the edge of the active material layer 20 ; and / or, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the first weld mark 511 away from the edge of the active material layer 20 .

[0274] Among the two edges of the first weld print 511 that are relatively distributed along the first direction, the edge close to the active material layer 20 is the edge of the first weld print 511 close to the active material layer 20 , and the edge away from the active material layer 20 is the edge of the first weld print 511 close to the active material layer 20 .

[0275] In some examples, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes beyond the first weld print 511 and approaches an edge of the active material layer 20 .

[0276] Along the thickness direction of the current collector 10, the projection of the edge of the first weld mark 511 close to the active material layer 20 is located within the projection of the first insulating member 41, and the first insulating member 41 covers the edge of the first weld mark 511 close to the active material layer 20; the first insulating member 41 can block burrs, metal debris and other components at the edge of the first weld mark 511 close to the active material layer 20, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0277] In some examples, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes beyond the first weld print 511 away from the edge of the active material layer 20 .

[0278] Along the thickness direction of the current collector 10, the projection of the edge of the first weld mark 511 away from the active material layer 20 is located within the projection of the first insulating member 41, and the first insulating member 41 covers the edge of the first weld mark 511 away from the active material layer 20; the first insulating member 41 can block burrs, metal debris and other components at the edge of the first weld mark 511 away from the active material layer 20, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0279] For example, the first insulating member 41 covers the first weld print portion 511 , and the first insulating member 41 can extend from the first weld print portion 511 back to the active material layer 20 until it protrudes from the edge of the first connecting sub-portion 311 away from the active material layer 20 , so that the first insulating member 41 covers the edge of the first connecting sub-portion 311 away from the active material layer 20 .

[0280] In some examples, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes from the first weld print 511 close to the edge of the active material layer 20 ; along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the first weld print 511 away from the edge of the active material layer 20 .

[0281] For example, along the thickness direction of the current collector 10, the projection of the first weld print 511 is located within the first insulating member 41, and the first insulating member 41 covers the entire first weld print 511. The first insulating member 41 can also cover the entire first weld print 511, thereby blocking burrs, metal debris and other components on the entire first weld print 511, thereby effectively reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0282] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the edges of the first weld print 511 that are relatively distributed along the first direction, and can block burrs, metal debris and other components at the edges of the first weld print 511 that are relatively distributed along the first direction, thereby effectively reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0283] In some embodiments, see Figure 8 and Figure 9 As shown, along the first direction, the edge of the first weld portion 511 away from the active material layer 20 is flush with the edge of the first connecting sub-portion 311 away from the active material layer 20 .

[0284] In some examples, along the thickness direction of the current collector 10, the projection of the edge of the first weld print 511 away from the active material layer 20 coincides with the edge of the first connecting sub-portion 311 away from the active material layer 20, so that the side of the first connecting sub-portion 311 away from the active material layer 20 is flush with the edge of the first weld print 511 away from the active material layer 20.

[0285] During the production process of some first pole pieces 1, the conductive component 30 is welded to the metal layer 12 of the current collector 10 and forms an equal-width weld mark extending along the second direction. During the cutting process of the first pole piece 1, cutting can be performed along the second direction on the equal-width weld mark to obtain the first connecting sub-portion 311 and the first weld mark portion 511, and cutting along the second direction on the equal-width weld mark is performed so that the edge of the first weld mark portion 511 away from the active material layer 20 and the side of the first connecting sub-portion 311 away from the active material layer 20 are cut at the same time, so that the side of the first connecting sub-portion 311 away from the active material layer 20 is flush with the edge of the first weld mark portion 511 away from the active material layer 20. The edge of the first weld mark 511 away from the active material layer 20 is cut, so that large burrs may be generated at the edge of the first weld mark 511 away from the active material layer 20, increasing the short circuit risk of the battery cell 100; and the first insulating member 41 protrudes from the edge of the first connecting sub-portion 311 away from the active material layer 20, so that the first insulating member 41 also protrudes from the edge of the first weld mark 511 away from the active material layer 20. The first insulating member 41 can cover the edge of the first weld mark 511 away from the active material layer 20, thereby blocking the burrs at the edge of the first weld mark 511 away from the active material layer 20, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0286] By adopting the technical solution of this embodiment, along the first direction, the edge of the first weld mark 511 away from the active material layer 20 is flush with the edge of the first connecting sub-portion 311 away from the active material layer 20, and the structure of the first electrode 1 is regular, which can facilitate the processing and production of the first electrode 1, and can also reduce the redundancy of the first connecting sub-portion 311, save space, and improve the energy density of the battery cell 100; in addition, the first insulating member 41 also protrudes from the edge of the first weld mark 511 away from the active material layer 20. The first insulating member 41 can cover the edge of the first weld mark 511 away from the active material layer 20, thereby blocking the burrs at the edge of the first weld mark 511 away from the active material layer 20, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0287] In some embodiments, see Figure 8 and Figure 9 As shown, along the second direction, two opposite edges of the transition portion 1212 are flush with two opposite edges of the first connecting sub-portion 311 , and two opposite edges of the first welded portion 511 are flush with two opposite edges of the first connecting sub-portion 311 .

[0288] In some examples, the two side surfaces of the transition portion 1212 that are relatively distributed along the second direction may refer to the two opposite edges of the transition portion 1212 along the second direction, and the two side surfaces of the first connecting sub-portion 311 that are relatively distributed along the second direction may refer to the two opposite edges of the first connecting sub-portion 311 along the second direction; among the two side surfaces of the transition portion 1212 that are relatively distributed along the second direction, the first weld print portion 511 extends from one of the side surfaces to the other side surface of the transition portion 1212, wherein the first weld print portion 511 may extend straightly along the second direction, or may extend obliquely or in an arc shape relative to the second direction, etc.; along the second direction, the size of the first weld print portion 511, the size of the transition portion 1212, and the size of the first connecting sub-portion 311 are equal.

[0289] In some examples, along the thickness direction of the current collector 10 , projections of two opposite edges of the transition portion 1212 along the second direction, projections of two opposite edges of the first connecting sub-portion 311 along the second direction, and projections of two opposite edges of the first weld print 511 along the second direction coincide with each other.

[0290] During the production process of some first pole pieces 1, the pole piece sheet has a weld mark continuously arranged along the second direction, and the pole piece sheet is cut at a distance along the second direction to obtain a plurality of first pole pieces 1. Along the second direction, the two opposite edges of the transition portion 1212 and the two opposite edges of the first connecting sub-portion 311 are obtained by cutting, so that along the second direction, the two opposite edges of the transition portion 1212 are respectively flush with the two opposite edges of the first connecting sub-portion 311, and the weld mark continuously arranged along the second direction is also cut into a plurality of first weld marks 511, so that along the second direction, the two opposite edges of the first weld mark 511 are respectively flush with the two opposite edges of the first connecting sub-portion 311.

[0291] By adopting the technical solution of this embodiment, the structures of the two side surfaces of the first pole piece 1 relatively distributed along the second direction are regular, which can facilitate the processing and production of the first pole piece 1, and can also reduce the redundancy of the first connecting sub-portion 311 and the transition portion 1212, save space, and improve the energy density of the battery cell 100; in addition, along the second direction, the size of the first weld portion 511 is equal to the size of the transition portion 1212, which increases the welding area between the transition portion 1212 and the first connecting sub-portion 311, which is beneficial to improving the current flow capacity of the first pole piece 1 and improving the fast charging performance of the battery cell 100.

[0292] In some embodiments, see Figures 7-11 As shown, the metal layer 12 also includes at least one protrusion 122, and the transition portion 1212 is connected between the protrusion 122 and the conductive portion 1211; along the second direction, the sum of the sizes of all the protrusions 122 is smaller than the size of the transition portion 1212, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10; the first connecting portion 31 includes at least one second connecting sub-portion 312, and the second connecting sub-portion 312 is connected between the first connecting sub-portion 311 and the second connecting portion 32, and the second connecting sub-portion 312 covers the surface of the protrusion 122 facing away from the insulating base 11, and the second connecting sub-portion 312 and the protrusion 122 correspond one to one.

[0293] Along the first direction, the protrusion 122 may refer to a protruding structure on the edge of the main body 121, that is, the protrusion 122 may be extended outward along the first direction from the side of the transition portion 1212 away from the conductive portion 1211. The protrusion 122 is not covered with the active material layer 20. The portion of the first connecting portion 31 covering the protrusion 122 forms the second connecting sub-portion 312. That is, the first connecting portion 31 is divided into two parts along the first direction, wherein the portion covering the protrusion 122 is the second connecting sub-portion 312, and the portion covering the transition portion 1212 is the first connecting sub-portion 311. The second connecting sub-portion 312 is connected between the first connecting sub-portion 311 and the second connecting portion 32. The interface between the first connecting sub-portion 311 and the second connecting sub-portion 312 can be referred to the side of the transition portion 1212 away from the active material layer 20 (refer to Figure 12 The dotted line N in the figure indicates that the transition portion 1212 leads to the side of the protruding portion 122; the interface between the second connecting sub-portion 312 and the second connecting portion 32 can be seen from the side of the protruding portion 122 facing away from the transition portion 1212 (see Figure 7 The dotted line M in the figure).

[0294] In some examples, along the second direction, the size of the protrusion 122 is l1, and the number of the protrusions 122 is N, wherein the number of the protrusions 122 is 1, and the protrusion 122 and the transition portion 1212 form a step structure, L2>l1; the number of the protrusions 122 is multiple, and the multiple protrusions 122 protrude from the edge on the same side of the transition portion 1212, and the multiple protrusions 122 are spaced apart along the second direction, and the structures of the multiple protrusions 122 are the same, L2>N*l1.

[0295] By adopting the technical solution of this embodiment, along the second direction, the size of the protrusion 122 is smaller than the size of the transition portion 1212, which can remove the edge redundancy of the current collector 10, save space, and improve the energy density of the battery cell 100; in addition, the protrusion 122 can also be connected to the second connecting sub-portion 312, thereby increasing the connection area between the metal layer 12 and the first connecting portion 31, improving the current flow capacity between the metal layer 12 and the first connecting portion 31, and improving the fast charging performance of the battery cell 100.

[0296] In some embodiments, see Figures 7-11 As shown, the first weld mark 51 includes at least one second weld mark portion 512 , and the second connecting sub-portion 312 is welded to the corresponding protruding portion 122 to form a second weld mark portion 512 .

[0297] The second connector portion 312 is welded to the surface of the corresponding protrusion 122 facing away from the insulating base 11, and the weld mark formed by the welding is the second weld mark portion 512. The second connector portion 312 and the second weld mark portion 512 are arranged in a one-to-one correspondence.

[0298] In some examples, the first weld mark 51 may only include the second weld mark portion 512 , that is, the second connecting sub-portion 312 is welded to the protruding portion 122 , and the first connecting sub-portion 311 is not welded to the transition portion 1212 .

[0299] In some examples, the first weld mark 51 may include a first weld mark portion 511 and a second weld mark portion 512, that is, the first connecting sub-portion 311 is welded to the transition portion 1212, and the second connecting sub-portion 312 is welded to the protrusion 122, which increases the welding area between the first connecting portion 31 and the metal layer 12, which is beneficial to improving the flow capacity between the first connecting portion 31 and the metal layer 12, and improving the fast charging capability of the battery cell 100.

[0300] In some examples, the first weld print portion 511 and the second weld print portion 512 can form a whole weld print; for example, the whole weld print can be obtained by cutting the above-mentioned equal-width weld print, and the boundary line between the first weld print portion 511 and the second weld print portion 512 can refer to the side of the second connecting sub-portion 312 away from the active material layer 20.

[0301] In some examples, the first weld print portion 511 and the second weld print portion 512 may also be two separate weld prints.

[0302] By adopting the technical solution of this embodiment, the second connecting sub-portion 312 is welded to the protruding portion 122 , thereby achieving connection between the first connecting portion 31 and the metal layer 12 .

[0303] Of course, in other examples, the first weld mark 51 may only include the first weld mark portion 511 , that is, the first connecting sub-portion 311 is welded to the transition portion 1212 , and the second connecting sub-portion 312 is not welded to the protruding portion 122 .

[0304] In some embodiments, see Figures 6 to 9 As shown, the first insulating member 41 covers at least a portion of the second weld print portion 512 .

[0305] In some examples, the first insulating member 41 covers a portion of the second weld print 512 . For example, along the thickness direction of the current collector 10 , the projection of the first insulating member 41 partially overlaps with the projection of the second weld print 512 .

[0306] In some examples, the first insulating member 41 covers the entire second weld print 512 . For example, along the thickness direction of the current collector 10 , the projection of the second weld print 512 falls within the projection range of the first insulating member 41 .

[0307] By adopting the technical solution of this embodiment, the first insulating member 41 can block burrs, metal debris and other components on the second weld print portion 512 , thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100 .

[0308] In some embodiments, see Figures 6-9 As shown, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes from the second weld portion 512 close to the edge of the active material layer 20 ; and / or, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the second weld portion 512 away from the edge of the active material layer 20 .

[0309] Among the two edges of the second weld print 512 that are relatively distributed along the first direction, the edge close to the active material layer 20 is the edge of the second weld print 512 close to the active material layer 20, and the edge away from the active material layer 20 is the edge of the second weld print 512 on the active material layer 20.

[0310] In some examples, the first weld print 511 and the second weld print 512 form a whole weld print, and the edge of the second weld print 512 close to the active material layer 20 coincides with the edge of the first weld print 511 away from the active material layer 20, that is, the edge of the second weld print 512 close to the active material layer 20 and the edge of the first weld print 511 away from the active material layer 20 can refer to the dividing line between the first weld print 511 and the second weld print 512.

[0311] In some examples, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes beyond the second weld print 512 and approaches an edge of the active material layer 20 .

[0312] Along the thickness direction of the current collector 10, the projection of the edge of the second weld mark 512 close to the active material layer 20 is located within the projection of the first insulating member 41, and the first insulating member 41 covers the edge of the second weld mark 512 close to the active material layer 20; the first insulating member 41 can block burrs, metal debris and other components at the edge of the second weld mark 512 close to the active material layer 20, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0313] For example, the first insulating member 41 covers the first connecting sub-portion 311 , and the first insulating member 41 can extend from the first connecting sub-portion 311 back to the active material layer 20 to the second weld print portion 512 , so that the first insulating member 41 covers the edge of the second weld print portion 512 close to the active material layer 20 .

[0314] In some examples, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes beyond the second weld print 512 away from the edge of the active material layer 20 .

[0315] Along the thickness direction of the current collector 10, the projection of the edge of the second weld mark 512 away from the active material layer 20 is located within the projection of the first insulating member 41, and the first insulating member 41 covers the edge of the second weld mark 512 away from the active material layer 20; the first insulating member 41 can block burrs, metal debris and other components at the edge of the second weld mark 512 away from the active material layer 20, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0316] For example, the first insulating member 41 covers the first connecting sub-portion 311, and the first insulating member 41 can extend from the first connecting sub-portion 311 back to the active material layer 20 to the second weld print portion 512 and extend outside the second weld print portion 512, so that the first insulating member 41 covers the edge of the second weld print portion 512 away from the active material layer 20.

[0317] In some examples, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes from the second weld portion 512 close to the edge of the active material layer 20 ; along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the second weld portion 512 away from the edge of the active material layer 20 .

[0318] For example, along the thickness direction of the current collector 10, the projection of the second weld print 512 is located within the first insulating member 41, and the first insulating member 41 covers the entire second weld print 512. The first insulating member 41 can also cover the entire second weld print 512, thereby blocking burrs, metal debris and other components on the entire second weld print 512, thereby effectively reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0319] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the edges of the second weld print 512 that are relatively distributed along the first direction, and can block burrs, metal debris and other components at the edges of the second weld print 512 that are relatively distributed along the first direction, thereby effectively reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0320] In some embodiments, see Figures 6 to 9 As shown, along the direction from the transition portion 1212 to the conductive portion 1211, the first insulating member 41 protrudes from the second connecting sub-portion 312 close to the edge of the active material layer 20; and / or, along the direction from the conductive portion 1211 to the transition portion 1212, the first insulating member 41 protrudes from the second connecting sub-portion 312 away from the edge of the active material layer 20.

[0321] Among the two side surfaces of the second connecting sub-portion 312 that are relatively distributed along the first direction, the side surface close to the active material layer 20 is the edge of the second connecting sub-portion 312 close to the active material layer 20 , and the side surface away from the active material layer 20 is the edge of the active material layer 20 of the second connecting sub-portion 312 .

[0322] In some examples, the first connecting sub-portion 311, the second connecting sub-portion 312 and the second connecting sub-portion 32 are an integrated structure, and the side of the second connecting sub-portion 312 close to the active material layer 20 coincides with the side of the first connecting sub-portion 311 away from the active material layer 20. The side of the second connecting sub-portion 312 close to the active material layer 20 and the side of the first connecting sub-portion 311 away from the active material layer 20 may refer to the interface between the first connecting sub-portion 311 and the second connecting sub-portion 312; the side of the second connecting sub-portion 32 close to the active material layer 20 coincides with the side of the second connecting sub-portion 312 away from the active material layer 20. The side of the second connecting sub-portion 32 close to the active material layer 20 and the side of the second connecting sub-portion 312 away from the active material layer 20 may refer to the interface between the second connecting sub-portion 32 and the second connecting sub-portion 312.

[0323] In some examples, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes beyond the second connecting sub-portion 312 close to the edge of the active material layer 20 .

[0324] Along the thickness direction of the current collector 10, the projection of the edge of the second connecting sub-portion 312 close to the active material layer 20 is located within the projection of the first insulating member 41, and the first insulating member 41 covers the edge of the second connecting sub-portion 312 close to the active material layer 20; the first insulating member 41 can block burrs, metal debris and other components at the edge of the second connecting sub-portion 312 close to the active material layer 20, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0325] For example, the first insulating member 41 covers the first connecting sub-portion 311 , and the first insulating member 41 can extend from the first connecting sub-portion 311 back to the active material layer 20 to the second connecting sub-portion 312 , so that the first insulating member 41 covers the edge of the second connecting sub-portion 312 close to the active material layer 20 .

[0326] In some examples, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes beyond the second connecting sub-portion 312 away from the edge of the active material layer 20 .

[0327] Along the thickness direction of the current collector 10, the projection of the edge of the second connecting sub-portion 312 away from the active material layer 20 is located within the projection of the first insulating member 41, and the first insulating member 41 covers the edge of the second connecting sub-portion 312 away from the active material layer 20; the first insulating member 41 can block burrs, metal debris and other components at the edge of the second connecting sub-portion 312 away from the active material layer 20, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0328] For example, the first insulating member 41 covers the first connecting sub-portion 311, and the first insulating member 41 can extend from the first connecting sub-portion 311 back to the active material layer 20 to the second connecting sub-portion 312 and extend outside the second connecting sub-portion 312, so that the first insulating member 41 covers the edge of the second connecting sub-portion 312 away from the active material layer 20.

[0329] In some examples, along the direction from the transition portion 1212 to the conductive portion 1211 , the first insulating member 41 protrudes from the second connecting sub-portion 312 close to the edge of the active material layer 20 ; along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the second connecting sub-portion 312 away from the edge of the active material layer 20 .

[0330] For example, along the thickness direction of the current collector 10, the projection of the second connecting sub-portion 312 is located within the first insulating member 41, and the first insulating member 41 covers the entire second connecting sub-portion 312. The first insulating member 41 can also cover the entire second connecting sub-portion 312, thereby blocking burrs, metal debris and other components on the entire second connecting sub-portion 312, thereby effectively reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0331] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the edges of the second connecting sub-portion 312 that are relatively distributed along the first direction, and can block burrs, metal debris and other components at the edges of the second connecting sub-portion 312 that are relatively distributed along the first direction, thereby effectively reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0332] In some embodiments, see Figures 6-9 As shown, the first insulating member 41 includes a first insulating portion 4121 and at least one second insulating portion 4122 . The first insulating portion 4121 covers the first connecting sub-portion 311 , and the second insulating portion 4122 covers the second connecting sub-portion 312 . The second insulating portion 4122 corresponds to the second connecting sub-portion 312 one by one.

[0333] In some examples, the portion of the first insulating member 41 covering the first connecting sub-portion 311 is the first insulating portion 4121, and the portion of the first insulating member 41 covering the second connecting sub-portion 312 is the second insulating portion 4122. The first insulating portion 4121 and the second insulating portion 4122 are arranged along the first direction, and the first insulating portion 4121 is closer to the active material layer 20 than the second insulating portion 4122. The number of the second insulating portions 4122 is the same as the number of the second connecting sub-portions 312, and the second insulating portions 4122 cover the second connecting sub-portions 312 in a one-to-one correspondence. The interface between the first insulating portion 4121 and the second insulating portion 4122 can be referred to as the side of the second connecting sub-portion 312 away from the active material layer 20 (see Figure 12 The dashed line N in the figure).

[0334] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the first connecting sub-portion 311 and the second connecting sub-portion 312, thereby increasing the coverage area of ​​the first insulating member 41, improving the insulation effect of the first insulating member 41, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0335] In some embodiments, see Figure 6 As shown, along the second direction, at least one of the two opposite sides of the first insulating portion 4121 protrudes from the corresponding side surface of the first connecting sub-portion 311 .

[0336] Among the two side portions of the first insulating portion 4121 that are opposite to each other along the second direction, one side portion protrudes from the side surface of the first connecting sub-portion 311 located on the same side as the side portion, and the other side portion protrudes from or does not protrude from the other side surface of the first connecting sub-portion 311.

[0337] During the production process of some first pole pieces 1, after the pole piece sheet is cut, burrs may be generated on the side of the first connecting sub-portion 311 along the second direction, thereby causing a short circuit in the battery cell 100; in particular, the second welded portion 512 obtained by cutting may cause large burrs to be generated on the side of the first connecting sub-portion 311 along the second direction, thereby increasing the risk of a short circuit in the battery cell 100.

[0338] By adopting the technical solution of this embodiment, the first insulating portion 4121 can block the burrs on the side of the first connecting sub-portion 311 along the second direction, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0339] In some embodiments, see Figures 6 to 9 As shown, there are multiple protrusions 122, multiple second connecting sub-parts 312, multiple protrusions 122 are arranged at intervals along the second direction, multiple second connecting sub-parts 312 are arranged at intervals along the second direction, multiple protrusions 122 and multiple second connecting sub-parts 312 are arranged in a one-to-one correspondence, there are multiple second connecting parts 32, multiple second connecting parts 32 are arranged at intervals along the second direction, the second connecting sub-parts 312 are connected to the second connecting parts 32 in a one-to-one correspondence, and multiple second connecting sub-parts 312 are connected to the edge of the first connecting sub-part 311 facing away from the active material layer 20; the first connecting sub-part 311 is continuously arranged along the second direction; there are multiple second insulating parts 4122, multiple second insulating parts 4122 are arranged along the second direction, and the second insulating parts 4122 are in a one-to-one correspondence with the second connecting sub-parts 312.

[0340] In some examples, there are multiple protrusions 122, which are spaced apart along the second direction. Each protrusion 122 is covered with a corresponding second connecting sub-portion 312, and each second connecting sub-portion 312 is connected to a corresponding second connecting portion 32. The multiple second connecting portions 32 are spaced apart along the second direction, and each second connecting sub-portion 312 is covered with a corresponding second insulating portion 4122. After the electrode sheet is wound, the multiple protrusions 122 can be stacked together, so that the multiple second connecting portions 32 are also stacked together to facilitate electrical connection with the electrode lead portion 2011.

[0341] By adopting the technical solution of this embodiment, the first connecting sub-part 311 is continuously arranged along the second direction, and multiple second connecting sub-parts 312 can be connected into a whole. The first connecting sub-part 311 can play a good supporting role for the second connecting sub-part 312, which can reduce the risk of the second connecting sub-part 312 being bent and inserted between the first pole piece 1 and the second pole piece 2, reduce the short circuit risk of the battery cell 100, and help improve the reliability of the battery cell 100; along the second direction, the size of the first connecting sub-part 311 is large, which is conducive to increasing the welding area between the first connecting sub-part 311 and the transition part 1212, and is conducive to increasing the welding area between the first connecting part 31 and the transition part 1212. The current-carrying capacity between the electrodes 121 and 122 is improved, the current-carrying capacity of the first electrode piece 1 is improved, and the fast charging performance and the reliability of the battery cell 100 are improved; the multiple protrusions 122 are arranged at intervals along the second direction, which is conducive to dividing the main body 121 into multiple areas along the second direction, and one area can correspond to one protrusion 122. The electrons in each area can be transmitted to the electrode lead-out portion 2011 through the corresponding protrusion 122, which can realize the regional transmission of electrons in the main body 121. The electron transmission path in each area is short to the corresponding protrusion 122, which is conducive to reducing the transmission distance of electrons, reducing the overall resistance of the first electrode piece 1, and improving the fast charging performance and the reliability of the battery cell 100.

[0342] In some embodiments, see Figure 6 As shown, two adjacent second insulating portions 4122 are connected.

[0343] In some examples, the sides of two adjacent second insulating portions 4122 that are close to each other are connected to form a whole.

[0344] In some examples, the first insulating member 41 extends along the second direction and is an equal-width structure. The first insulating member 41 is divided into two parts in the first direction, where the part close to the active material layer 20 is the first insulating part 4121, and the part away from the active material layer 20 can be divided into multiple second insulating parts 4122 along the second direction. The multiple second insulating parts 4122 are connected in sequence along the second direction to form an integral structure.

[0345] By adopting the technical solution of this embodiment, two adjacent second insulating parts 4122 can be directly connected to form an integral structure, which can facilitate the installation of the first insulating part 41; at the same time, the second insulating part 4122 can also cover the two opposite edges of the second connecting sub-part 312 along the second direction, blocking the pointed protrusions, metal debris and other components on the two opposite side surfaces of the second connecting sub-part 312 along the second direction, thereby increasing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0346] In some embodiments, see Figure 8 and Figure 9 As shown, along the first direction, the first weld mark 51 and the active material layer 20 are spaced apart.

[0347] Along the thickness direction of the current collector 10 , the projection of the first weld mark 51 does not overlap with the projection of the active material layer 20 .

[0348] In some examples, the first electrode 1 is a positive electrode, and there is a gap between the first weld mark 51 and the active material layer 20. The gap can be used to provide a spacing space between the first connecting sub-portion 311 and the active material layer 20 to reduce the risk of lithium plating in the first electrode 1 caused by the contact between the first connecting sub-portion 311 and the active material layer 20. In addition, a spacing space can be provided between the first weld mark 51 and the side of the first connecting sub-portion 311 close to the active material layer 20, so that the first weld mark 51 will not extend to the side of the first connecting sub-portion 311 close to the active material layer 20, reducing the risk of the first connecting sub-portion 311 being welded through or cracked at the side of the active material layer 20, which is beneficial to reducing burrs, metal debris and other components generated by welding, and is beneficial to improving the reliability of the battery cell 100.

[0349] In some examples, the first electrode 1 is a negative electrode, and there is a gap between the first weld mark 51 and the active material layer 20, which can provide a spacing space between the first weld mark 51 and the side of the first connecting sub-portion 311 close to the active material layer 20, so that the first weld mark 51 will not extend to the side of the first connecting sub-portion 311 close to the active material layer 20, reducing the risk of the first connecting sub-portion 311 being welded through or cracked at the side of the active material layer 20, which is beneficial to reducing burrs, metal debris and other components generated by welding, and is beneficial to improving the reliability of the battery cell 100; wherein, the first connecting sub-portion 311 can be connected to the active material layer 20, or can be set at intervals.

[0350] By adopting the technical solution of this embodiment, a gap is formed between the first weld mark 51 and the active material layer 20, so that the welding of the first connection part 31 and the metal layer 12 will not be welded to the active material layer 20, reducing the risk of cold welding between the first connection part 31 and the metal layer 12, and improving the reliability of the battery cell 100.

[0351] In some embodiments, see Figure 8 and Figure 9 As shown, along the first direction, the distance between the first weld mark 51 and the active material layer 20 is S1, wherein 0.3 mm ≤ S1 ≤ 5 mm.

[0352] In some examples, the first weld mark 51 only includes a first weld mark portion 511 , and S1 is a distance between the first weld mark portion 511 and the active material layer 20 .

[0353] In some examples, the first weld mark 51 only includes the second weld mark portion 512 , and S1 is the distance between the second weld mark portion 512 and the active material layer 20 .

[0354] In some examples, the first weld mark 51 includes a first weld mark portion 511 and a second weld mark portion 512 , and S1 is a distance between the first weld mark portion 511 and the active material layer 20 .

[0355] The design of S1 ≥ 0.3 mm ensures that there is a distance between the first weld mark 51 and the active material layer 20, and the first connection portion 31 will not be welded to the active material layer 20, reducing the risk of cold welding between the first connection portion 31 and the metal layer 12. The design of S1 ≤ 5 mm prevents the distance between the first weld mark 51 and the active material layer 20 from being too large, which is beneficial to increasing the coverage area of ​​the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell 100.

[0356] The value of S1 can be 0.3 mm, 5 mm, or any value between 0.3 mm and 5 mm. For example, the value of S1 can be, but is not limited to, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 2.5 mm, 2.8 mm, 3 mm, 4 mm, or 5 mm.

[0357] By adopting the technical solution of this embodiment, the design of 0.3mm≤S1≤5mm prevents the first weld mark 51 from being welded to the active material layer 20, reducing the risk of cold welding between the first connecting portion 31 and the metal layer 12, which is beneficial to improving the connection reliability between the first connecting portion 31 and the metal layer 12, and improving the reliability of the battery cell 100. In addition, the spacing between the active material layer 20 and the first weld mark 51 is reasonable, and the active material layer 20 and the first weld mark 51 are relatively close. Then, when the size of the metal layer 12 in the first direction is constant, the active material layer 20 can cover a larger area, which is beneficial to improving the energy density of the battery cell 100.

[0358] In some embodiments, 0.5 mm ≤ S1 ≤ 2.8 mm.

[0359] By adopting the technical solution of this embodiment and the design of 0.5 mm ≤ S1 ≤ 2.8 mm, the distance between the active material layer 20 and the first weld mark 51 is more reasonable, which can better balance the connection reliability of the first connecting portion 31 and the energy density of the battery cell 100.

[0360] In some embodiments, see Figures 7-9 As shown, the electrode assembly 101 includes a second insulating member 42 , which covers the surface of the metal layer 12 facing away from the insulating substrate 11 . The entire second insulating member 42 is located between the first weld mark 51 and the active material layer 20 .

[0361] The second insulating member 42 may be a component made of an insulating material, such as PP (polypropylene), PET (polyethylene terephthalate), etc. The second insulating member 42 may be, but is not limited to, an insulating coating, an insulating adhesive (such as hot melt adhesive), or an insulating tape.

[0362] The second insulating member 42 covers a portion of the metal layer 12 between the first weld mark 51 and the active material layer 20 .

[0363] In some examples, a portion of the second insulating member 42 may be located between the first connecting sub-portion 311 and the metal layer 12, and another portion of the second insulating member 42 may be located between the first connecting sub-portion 311 and the active material layer 20; or, the entire second insulating member 42 may be located between the first connecting sub-portion 311 and the active material layer 20.

[0364] By adopting the technical solution of this embodiment, the second insulating member 42 covers the portion of the metal layer 12 located between the first weld mark 51 and the active material layer 20, thereby achieving insulation of this portion, which is beneficial to reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0365] In some embodiments, see Figure 12 As shown, along the first direction, the first connecting sub-portion 311 is spaced apart from the active material layer 20 .

[0366] Along the thickness direction of the current collector 10 , the projection of the first connecting sub-portion 311 does not overlap with the projection of the active material layer 20 .

[0367] By adopting the technical solution of this embodiment, the first connecting sub-portion 311 is not in contact with the active material layer 20 , which can reduce the mutual influence between the two and is conducive to improving the performance of the battery cell 100 .

[0368] In some embodiments, at least a portion of the second insulating member 42 is located between the first connecting sub-portion 311 and the active material layer 20 .

[0369] In some examples, a portion of the second insulating member 42 is located in the space formed by the first connecting sub-portion 311 and the active material layer 20 , and another portion of the second insulating member 42 is located between the first connecting sub-portion 311 and the metal layer 12 .

[0370] In some examples, the entire second insulating member 42 is located in the spacing space formed by the first connecting sub-portion 311 and the active material layer 20, and the second insulating member 42 does not extend between the first connecting sub-portion 311 and the metal layer 12. This is conducive to the spacing of the first weld mark 51 and the second insulating member 42, reducing the risk of cold welding between the first connecting portion 31 and the metal layer 12.

[0371] In some battery cells 100, the second connecting portion 32 is bent and then connected to the electrode lead-out portion 2011. In the process of bending the second connecting portion 32, the transition portion 1212 will be bent accordingly, so that the portion of the transition portion 1212 located between the first connecting sub-portion 311 and the active material layer 20 may have problems such as cracks. The second insulating member 42 covers the portion of the transition portion 1212 located between the first connecting sub-portion 311 and the active material layer 20. The second insulating member 42 can support this portion, thereby reducing the risk of cracks in this portion. In addition, the second insulating member 42 covers the portion of the transition portion 1212 located between the first connecting sub-portion 311 and the active material layer 20, and can also achieve insulation of this portion, reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0372] In some embodiments, see Figures 5-7 As shown, the electrode assembly 101 also includes a second pole piece 2 with opposite polarity to the first pole piece 1, and the second pole piece 2 includes a main functional portion 210 and a pole ear portion 220 arranged along a first direction, and the end of the main functional portion 210 close to the transition portion 1212 has a first end face 2101, and the pole ear portion 220 extends outward from the first end face 2101; along the thickness direction of the current collector 10, the projection of the first end face 2101 is located within the projection of the second insulating member 42.

[0373] The main functional part 210 may refer to the main structure of the second pole piece 2, and the pole ear part 220 may refer to the protruding structure extending from the end of the main functional part 210 near the transition part 1212. The pole ear part 220 is used to be electrically connected to the electrode lead-out part 2011. The conductive component 30 and the pole ear part 220 are electrically connected to the electrode lead-out part 2011 with different polarity to realize the charging and discharging of the battery cell 100.

[0374] Among the two end surfaces of the main functional portion 210 that are opposite to each other along the first direction, the end surface close to the transition portion 1212 forms a first end surface 2101 .

[0375] By adopting the technical solution of this embodiment, the first end surface 2101 and the second insulating member 42 are arranged opposite to each other, and the second insulating member 42 can block the burrs at the first end surface 2101, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0376] In some embodiments, see Figure 7 As shown, along the first direction, one side of the first insulating member 41 covers the first connecting sub-portion 311 , and the other side of the first insulating member 41 covers at least a portion of the second insulating member 42 .

[0377] Along the thickness direction of the current collector 10 , the projection of the first insulating member 41 partially overlaps with the projection of the second insulating member 42 .

[0378] The first insulating member 41 may cover a portion of the second insulating member 42 , or may cover the entire second insulating member 42 .

[0379] In some examples, the first insulating member 41 may be fixed to the second insulating member 42 by bonding or static adsorption. In other examples, the first insulating member 41 may be fixed to the second insulating member 42 by other methods.

[0380] By adopting the technical solution of this embodiment, the first insulating member 41 and the second insulating member 42 can achieve double-layer insulation, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0381] In some embodiments, see Figure 13 As shown, along the first direction, one side of the first insulating member 41 covers the first connecting sub-portion 311 , and the other side of the first insulating member 41 covers at least a portion of the active material layer 20 .

[0382] It can be understood that, of the two side portions of the first insulating member 41 relatively distributed along the first direction, one side portion covers the first connecting sub-portion 311, and the other side portion covers at least a portion of the active material layer 20, wherein the first insulating member 41 can cover the end of the active material layer 20 facing the first connecting sub-portion 311, or can cover the entire active material layer 20.

[0383] In some examples, along the first direction, the first insulating member 41 may extend from the active material layer 20 to the first connecting sub-portion 311 and beyond the first connecting sub-portion 311, so that the portion of the metal layer 12 between the first connecting sub-portion 311 and the active material layer 20 is covered by the first insulating member 41, thereby achieving insulation of this portion. The portion of the metal layer 12 between the first connecting sub-portion 311 and the active material layer 20 may be covered by the second insulating member 42 or may not be covered by the second insulating member 42.

[0384] In some examples, a portion of the metal layer 12 between the first connecting sub-portion 311 and the active material layer 20 may be covered with the second insulating member 42 , and the first insulating member 41 may completely cover the second insulating member 42 .

[0385] In some examples, the portion of the metal layer 12 located between the first connecting sub-portion 311 and the active material layer 20 may not be covered by the second insulating member 42, and the first insulating member 41 may cover the portion of the metal layer 12 located between the first connecting sub-portion 311 and the active material layer 20 to achieve insulation of this portion, which is beneficial to improving the reliability of the battery cell 100. In addition, the second insulating member 42 can be omitted to save costs. At the same time, the active material layer 20 can be used to cover the original position of the second insulating member 42, which can increase the coverage area of ​​the active material layer 20 on the metal layer 12, which is beneficial to improving the energy density of the battery cell 100.

[0386] By adopting the technical solution of this embodiment, the first insulating member 41 has a wide coverage area and a good insulation effect, which is beneficial to improving the reliability of the battery cell 100; the first insulating member 41 can cover the end of the active material layer 20 close to the transition portion 1212, and can block the burrs of the active material layer 20 close to the transition portion 1212, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0387] In some embodiments, see Figure 13 As shown, along the first direction, the size of the portion of the first insulating member 41 covering the active material layer 20 is H, wherein 0.2 mm ≤ H ≤ 1.0 mm.

[0388] The design of H≥0.2mm enables the first insulating member 41 to cover the end of the active material layer 20 near the transition portion 1212. The first insulating member 41 can block the burrs at the end of the active material layer 20 near the transition portion 1212, thereby improving the reliability of the battery cell 100. The design of H≤1.0mm enables the portion of the first insulating member 41 covering the active material layer 20 to not be too large, thereby reducing the weight and volume of the first insulating member 41, thereby improving the energy density of the battery cell 100.

[0389] In some examples, the value of H may be 0.2 mm, 1 mm, or any value between 0.2 mm and 1.0 mm. For example, the value of H may be, but is not limited to, 0.2 mm, 0.3 mm, 0.4 mm, 0.6 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0390] By adopting the technical solution of this embodiment, along the first direction, the size of the portion of the first insulating member 41 covering the active material layer 20 is reasonable, which can simultaneously take into account the burrs at the end of the active material layer 20 near the transition portion 1212 and the energy density of the battery cell 100.

[0391] In some embodiments, 0.3 mm ≤ H ≤ 0.8 mm.

[0392] By adopting the technical solution of this embodiment, along the first direction, the size of the portion of the first insulating member 41 covering the active material layer 20 is more reasonable, which can better balance the problem of blocking the burrs at the end of the active material layer 20 near the transition portion 1212 and the energy density of the battery cell 100.

[0393] In some embodiments, see Figure 5 and Figure 12 As shown, the electrode assembly 101 also includes a second electrode plate 2 with opposite polarity to the first electrode plate 1, and the second electrode plate 2 includes a main functional portion 210 and a pole ear portion 220 arranged along a first direction, and the end of the main functional portion 210 close to the transition portion 1212 has a first end face 2101, and the pole ear portion 220 extends outward from the first end face 2101; along the direction of the conductive portion 1211 toward the transition portion 1212, the first connecting sub-portion 311 away from the side of the active material layer 20 does not protrude from the first end face 2101.

[0394] Along the thickness direction of the current collector 10, the projection of the side of the first connecting sub-portion 311 away from the active material layer 20 falls within the projection range of the main functional portion 210, so that the first end face 2101 is arranged opposite to the hollow area of ​​the conductive component 30 where the second connecting portion 32 or the second connecting sub-portion 312 does not extend.

[0395] By adopting the technical solution of this embodiment, the first end surface 2101 is arranged opposite to the hollow area of ​​the conductive component 30, which can reduce the short circuit risk of the battery cell 100 and is conducive to improving the reliability of the battery cell 100.

[0396] In some embodiments, see Figure 5 and Figure 12 As shown, along the thickness direction of the current collector 10 , the projection of the first end surface 2101 is located within the projection of the first connecting sub-portion 311 .

[0397] Along the direction of the conductive part 1211 toward the transition part 1212, the first connecting sub-part 311 protrudes from the first end face 2101 away from the side of the active material layer 20, so that the edge of the first connecting sub-part 311 away from the active material layer 20 is not arranged opposite to the main functional part 210, which can reduce the short circuit risk of the battery cell 100 and is conducive to improving the reliability of the battery cell 100.

[0398] In some embodiments, see Figure 5 and Figure 7 As shown, the electrode assembly 101 also includes a second pole piece 2 with opposite polarity to the first pole piece 1, and the second pole piece 2 includes a main functional portion 210 and a pole ear portion 220 arranged along a first direction, and the end of the main functional portion 210 close to the transition portion 1212 has a first end face 2101, and the pole ear portion 220 extends outward from the first end face 2101; along the thickness direction of the current collector 10, the projection of the first end face 2101 is located within the projection of the first insulating member 41.

[0399] In some examples, the first insulating member 41 includes a first insulating portion 4121 and a second insulating portion 4122. Along the thickness direction of the current collector 10, the projection of the first end face 2101 is located within the projection of the first insulating portion 4121, the first end face 2101 is arranged opposite to the first connecting sub-portion 311, and along the direction from the conductive portion 1211 to the transition portion 1212, the main functional portion 210 does not protrude beyond the first connecting sub-portion 311 away from the edge of the active material layer 20; or, the projection of the first end face 2101 is located within the projection of the second insulating portion 4122, the first end face 2101 is arranged opposite to the second insulating portion 4122, and along the direction from the conductive portion 1211 to the transition portion 1212, the main functional portion 210 protrudes beyond the first connecting sub-portion 311 away from the edge of the active material layer 20.

[0400] By adopting the technical solution of this embodiment, the first insulating member 41 can block the pointed protrusion at the first end surface 2101 , thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100 .

[0401] In some embodiments, see Figure 7 As shown, there are two metal layers 12, which cover the opposite sides of the insulating base 11 along the thickness direction of the current collector 10; there are two active material layers 20, which cover the conductive parts 1211 of the two metal layers 12 respectively; there are two conductive components 30, which have first connecting parts 31 connected to the two metal layers 12 respectively; there are two first insulating parts 41, which cover the first connecting sub-parts 311 of the two conductive components 30 respectively.

[0402] The number of metal layers 12, the number of first insulating parts 41, the number of active material layers 20 and the number of conductive components 30 are all two. The two metal layers 12 are respectively covered on the opposite sides of the insulating base 11 along the thickness direction, and the two active material layers 20 are respectively covered on the conductive parts 1211 of the two metal layers 12; the first connecting part 31 of one conductive component 30 is connected to the surface of one of the metal layers 12 facing away from the insulating base 11, and the first connecting part 31 of the other conductive component 30 is connected to the surface of the other metal layer 12 facing away from the insulating base 11. The two first insulating parts 41 are located on the opposite sides of the insulating base 11 along the thickness direction and respectively cover the first connecting sub-parts 311 of the two conductive components 30.

[0403] By adopting the technical solution of this embodiment, the first connecting parts 31 of the two conductive components 30 are respectively welded to the metal layers 12 located on opposite sides of the insulating base 11, so that the second connecting parts 32 of the two conductive components 30 can be connected, thereby electrically conducting the two metal layers 12, thereby breaking the insulation limitation of the insulating base 11, and effectively improving the conductivity of the first pole piece 1, improving the fast charging performance of the battery cell 100, reducing the heating risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0404] In some embodiments, see Figure 6 As shown, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the first connecting sub-portion 311 to form a blocking portion 4131 , and along the second direction, the blocking portion 4131 is located on the side of the second connecting portion 32 , wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10 .

[0405] The blocking portion 4131 may refer to a portion of the first insulating member 41 protruding from an edge of the first connecting sub-portion 311 away from the active material layer 20 , and is located on one of two opposite sides of the second connecting portion 32 along the second direction.

[0406] In some examples, along the thickness direction of the current collector 10 , the barrier portion 4131 may refer to a portion of the first insulating member 41 that is located outside the projection of the metal layer 12 .

[0407] In some examples, the first insulating member 41 includes a first insulating portion 4121 and a second insulating portion 4122. The portions of two adjacent first insulating portions 4121 corresponding to the area where the first connector 311 does not extend from the second connector 312 form a blocking portion 4131. During the manufacture or use of the battery cell 100, burrs, metal debris, and other components may form in the area where the first connector 311 does not extend from the second connector 312, increasing the risk of a short circuit in the battery cell 100. The blocking portion 4131 can block burrs, metal debris, and other components in these areas, reducing the risk of a short circuit in the battery cell 100 and improving the reliability of the battery cell 100.

[0408] By adopting the technical solution of this embodiment, the blocking portion 4131 can block the first connecting sub-portion 311 from burrs, metal debris and other components at the edge of the active material layer 20, reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0409] In some embodiments, see Figure 12 As shown, the blocking portions 4131 of the two first insulating members 41 are in contact with each other.

[0410] Along the thickness direction of the current collector 10, the two first insulating members 41 are located on opposite sides of the first pole piece 1, and the blocking portions 4131 of the two first insulating members 41 are staggered with the second connecting sub-portion 312 and the second connecting portion 32 of the conductive component 30, so that the blocking portions 4131 of the two first insulating members 41 can be directly bonded together, wherein the blocking portions 4131 of the two first insulating members 41 can be bonded together by, but not limited to, bonding or static adsorption.

[0411] By adopting the technical solution of this embodiment, after the blocking parts 4131 of the two first insulating parts 41 are bonded together, the burrs, metal debris and other components at the edge of the first connecting sub-part 311 away from the active material layer 20 can be wrapped, thereby blocking the burrs at the edge of the first connecting sub-part 311 away from the active material layer 20, reducing the risk of metal debris falling, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0412] In some embodiments, see Figure 7 As shown, the second connection portions 32 of the two conductive members 30 are welded to form a second weld mark 52 .

[0413] In some examples, along the direction from the conductive portion 1211 to the transition portion 1212, the portion of the conductive member 30 that protrudes from the side of the protrusion 122 away from the active material layer 20 forms the second connecting portion 32. In this way, the second connecting portions 32 of the two conductive members 30 can be directly brought into close proximity and welded together, and the welding mark left is the second weld mark 52. The second connecting portions 32 of the two conductive members 30 can be welded by ultrasonic welding, laser welding, or the like.

[0414] By adopting the technical solution of this embodiment, the second connecting parts 32 of the two conductive components 30 are welded to electrically connect the metal layers 12 located on opposite sides of the insulating substrate 11, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductivity of the first pole piece 1, improving the fast charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the reliability of the battery cell 100.

[0415] In some embodiments, see Figure 7 As shown, the first insulating member 41 covers at least a portion of the second weld mark 52 .

[0416] The first insulating member 41 may cover a portion of the second weld mark 52 , or the first insulating member 41 may cover the entire second weld mark 52 .

[0417] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the second weld mark 52, thereby blocking the pointed protrusions, metal debris and other components on the second weld mark 52, reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0418] In some embodiments, see Figure 7 As shown, along the direction from the conductive portion 1211 to the transition portion 1212 , the first insulating member 41 protrudes from the edge of the second weld mark 52 away from the active material layer 20 .

[0419] Among the two edges of the second weld mark 52 that are opposite to each other along the first direction, the edge away from the active material layer 20 is the edge of the second weld mark 52 away from the active material layer 20 .

[0420] In some examples, along the direction from the conductive portion 1211 to the transition portion 1212, the first insulating member 41 may extend from the first connecting sub-portion 311 back toward the active material layer 20 to the second connecting portion 32 and protrude the edge of the second weld mark 52 back toward the active material layer 20; that is, along the thickness direction of the current collector 10, the projection of the second weld mark 52 falls within the projection of the first insulating member 41, so that the first insulating member 41 can cover the entire second weld mark 52.

[0421] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the entire second weld mark 52, blocking burrs, metal debris and other components on the second weld mark 52, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0422] In some embodiments, see Figure 7 As shown, the current collector 10 includes a conductive protection layer 13 , at least a portion of which is located between the active material layer 20 and the conductive portion 1211 .

[0423] In some examples, the conductive protective layer 13 may refer to a conductive structure disposed between the active material layer 20 and the conductive portion 1211. This conductive structure is electrically conductive, enabling electrons to be transferred between the active material layer 20 and the conductive portion 1211, thereby enabling electrical energy input or output of the battery cell 100. The conductive protective layer 13 may have a uniform thickness or a variably thick structure.

[0424] For example, a portion of the conductive protection layer 13 is located between the active material layer 20 and the conductive portion 1211 , and another portion covers the transition portion 1212 and protrudes out of the active material layer 20 .

[0425] Illustratively, the entire conductive protection layer 13 is located between the active material layer 20 and the conductive portion 1211 .

[0426] In some examples, the conductive protective layer 13 may contain conductive carbon black and a binder, which, on the one hand, acts as a buffer and lubricant between the active material layer 20 and the conductive portion 1211, thereby alleviating the damage to the metal layer 12 caused by particles in the active material layer 20 during the rolling process of the first electrode 1; on the other hand, the conductive carbon black can reduce the contact resistance between the particles in the active material layer 20 and the conductive portion 1211, thereby improving the performance of the battery cell 100.

[0427] 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 damage the metal layer 12, thereby causing the conductive part 1211 to be prone to cracks and other problems. The conductive protective layer 13 of the embodiment of the present application can separate the active material layer 20 and the conductive part 1211, thereby protecting the conductive part 1211 and reducing the risk of cracks in the conductive part 1211 caused by rolling the active material layer 20, which is beneficial to improving the electron transmission capacity of the conductive part 1211 and improving the fast charging performance of the battery cell 100.

[0428] In some embodiments, see Figure 7 As shown, along the direction from the conductive portion 1211 to the transition portion 1212 , the conductive protection layer 13 protrudes from the end of the active material layer 20 close to the first connecting sub-portion 311 .

[0429] In some examples, a portion of the conductive protective layer 13 covers the conductive portion 1211, and another portion covers the transition portion 1212. The conductive protective layer 13 protrudes from the active material layer 20, and the conductive protective layer 13 can completely separate the metal layer 12 and the active material layer 20; in addition, it can also provide an epitaxial space for the active material layer 20 during the rolling process, which is beneficial to reduce the risk of direct contact between the active material layer 20 and the metal layer 12.

[0430] 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 for the metal layer 12, and the first pole piece 1 has better current carrying capacity, which is beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0431] In some embodiments, see Figure 7 As shown, along the direction from the conductive portion 1211 to the transition portion 1212 , the protruding length of the conductive protection layer 13 protruding from the active material layer 20 ranges from 0.3 mm to 0.8 mm.

[0432] The protruding distance of the conductive protection layer 13 from the active material layer 20 is S2, where 0.3 mm ≤ S2 ≤ 0.8 mm. The value of S2 can be 0.3 mm, 0.8 mm, or any value between 0.3 mm and 0.8 mm. For example, the value of S2 can be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm.

[0433] The design of S2≥0.3mm allows 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 for the metal layer 12, and the first pole piece 1 has better current carrying capacity, which is beneficial to improving the fast charging performance and reliability of the battery cell 100. The design of S2≤0.8mm prevents the conductive protective layer 13 from protruding too much from the active material layer 20 and occupying more space, which is beneficial to saving the internal space of the battery cell 100 and improving the energy density of the battery cell 100.

[0434] By adopting the technical solution of this embodiment, the current capacity and energy density of the battery cell 100 can be better taken into account.

[0435] In some embodiments, the first connection portion 31 is welded to the surface of the metal layer 12 facing away from the insulating base 11 to form a first weld mark 51 . Along the first direction, the conductive protection layer 13 and the first weld mark 51 are spaced apart.

[0436] In some examples, the conductive protection layer 13 is spaced apart from the first connecting sub-portion 311 , and the second insulating portion 4122 covers a portion of the conductive protection layer 13 between the first connecting sub-portion 311 and the active material layer 20 .

[0437] By adopting the technical solution of this embodiment, the first connection part 31 will not be welded to the conductive protective layer 13, which can reduce the risk of cold welding between the first connection part 31 and the metal layer 12 and is conducive to improving the reliability of welding between the first connection part 31 and the metal layer 12.

[0438] In some embodiments, see Figure 7 As shown, the first insulating member 41 is connected to the first pole piece 1 .

[0439] In some examples, the first insulating member 41 may be connected to the transition portion 1212 , the conductive component 30 , or the active material layer 20 , wherein the first insulating member 41 may be connected to the first pole piece 1 by bonding or static adsorption.

[0440] By adopting the technical solution of this embodiment, the first insulating member 41 is connected to the first pole piece 1, and the first insulating member 41 can be fixed, thereby stably blocking the first connecting sub-portion 311 from burrs, metal debris and other components at the edge of the active material layer 20, which is beneficial to improving the reliability of the battery cell 100.

[0441] In some embodiments, see Figure 7 、 Figure 14 and Figure 15 As shown, the first insulating member 41 includes an insulating base layer 4111 and an adhesive layer 4112 , and the adhesive layer 4112 is bonded between the insulating base layer 4111 and the first pole piece 1 .

[0442] The first insulating member 41 is in the form of an adhesive tape. The insulating base layer 4111 may refer to the main body 121 of the first insulating member 41. The adhesive layer 4112 may refer to the adhesive covering the surface of the insulating base layer 4111. The insulating base layer 4111 may be made of polyethylene terephthalate, polypropylene, or the like. The adhesive layer 4112 may be made of acrylic, rubber, latex, or the like. The structure of the first insulating member 41 may be the same as or different from that of the second insulating member 42.

[0443] In some battery cells 100, insulating glue (for example, hot melt glue, etc.) can be applied to the first weld mark 51 to form the first insulating part 41, but the coating operation may have the risk of missing coating. In addition, the insulating glue also needs to be applied thickly to cover burrs, metal debris and other components on the first weld mark 51, which is not conducive to improving the volume energy density of the battery cell 100.

[0444] By adopting the technical solution of this embodiment, the first insulating member 41 adopts the structure of tape, and the first insulating member 41 can be directly adhered to the first pole piece 1, reducing the risk of leakage coverage; the insulating base layer 4111 and the adhesive layer 4112 cover the first pole piece 1 to block the burrs on the first pole piece 1, and the thickness of the insulating base layer 4111 and the adhesive layer 4112 do not need to be set to be large, which is beneficial to improving the energy density of the battery cell 100; the insulating base layer 4111 has good structural strength and can stably block the burrs on the first pole piece 1, thereby improving the reliability of the battery cell 100; the adhesive layer 4112 can stably fix the insulating base layer 4111 on the first pole piece 1, thereby reducing the risk of the first insulating member 41 falling off; the metal debris on the first pole piece 1 can also be adhered to the adhesive layer 4112, which can effectively reduce the risk of metal debris on the first pole piece 1 falling off and reduce the short circuit risk of the battery cell 100.

[0445] In some embodiments, see Figure 7 、 Figure 14 and Figure 15 As shown, the thickness of the insulating base layer 4111 is in the range of 6 μm to 15 μm; and / or the thickness of the adhesive layer 4112 is in the range of 0.5 μm to 3 μm.

[0446] In some examples, the thickness of the insulating base layer 4111 ranges from 6 μm to 15 μm.

[0447] The layer thickness of the insulating base layer 4111 is T1, 6μm≤T1≤15μm. It can be understood that the value of T1 can be 6μm, 15μm and any value between 6μm and 15μm. For example, the value of T1 can be but is not limited to 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, and 16μm.

[0448] The design of T1≥6μm ensures that the insulating base layer 4111 has a certain thickness to block burrs and achieve insulation; the design of T1≤15μm ensures that the thickness of the insulating base layer 4111 is not too large, which is beneficial to reducing the volume occupied by the first insulating part 41 and improving the energy density of the battery cell 100.

[0449] By adopting the technical solution of this embodiment, both the internal insulation and the energy density of the battery cell 100 can be taken into consideration.

[0450] In some examples, the thickness of the adhesive layer 4112 ranges from 0.5 μm to 3 μm.

[0451] The thickness of the adhesive layer 4112 is T2, 0.5μm≤T2≤3μm. It can be understood that the value of T2 can be 0.3μm, 3μm, and any value between 0.3μm and 3μm. For example, the value of T2 can be but is not limited to 0.3μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, and 3μm.

[0452] The design of T2≥0.5μm ensures that the bonding layer 4112 has a certain thickness, so that the first insulating member 41 can be stably bonded to the first pole piece 1, and the insulation reliability of the first insulating member 41 is good; the design of T2≤3μm ensures that the thickness of the bonding layer 4112 is not too large, which is beneficial to reducing the volume occupied by the first insulating member 41 and improving the energy density of the battery cell 100.

[0453] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell 100 can be taken into consideration.

[0454] In some examples, the thickness of the insulating base layer 4111 ranges from 6 μm to 15 μm; the thickness of the adhesive layer 4112 ranges from 0.5 μm to 3 μm.

[0455] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell 100 can be taken into consideration.

[0456] In one embodiment, see Figure 7 As shown, along the first direction, the size of the first insulating member 41 is W, wherein 3 mm ≤ W ≤ 9 mm.

[0457] In some examples, the first insulating member 41 includes a first insulating portion 4121 and a second insulating portion 4122 , and W is equal to an overall size of the first insulating portion 4121 and the second insulating portion 4122 along the first direction.

[0458] 3mm≤W≤9mm. It can be understood that the value of W can be 3mm, 9mm, and any value between 3mm and 9mm. For example, the value of W can be but is not limited to 3mm, 4mm, 4.5mm, 5mm, 6mm, 6.5mm, 7mm, 8mm, and 9mm.

[0459] The design of W≥3mm ensures that the first insulating member 41 has a certain size along the first direction. The first insulating member 41 can better block the burrs at the edge of the first connecting sub-portion 311 facing away from the active material layer 20, thereby realizing the internal insulation of the battery cell 100; the design of W≤9mm ensures that the size of the first insulating member 41 along the first direction is not too large, which is beneficial to reducing the volume occupied by the first insulating member 41 and improving the energy density of the battery cell 100.

[0460] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell 100 can be taken into consideration.

[0461] In some embodiments, 4.5 mm ≤ W ≤ 6.5 mm.

[0462] By adopting the technical solution of this embodiment, the size of the first insulating member 41 along the first direction is relatively reasonable, which can better balance the insulation reliability and energy density of the battery cell 100.

[0463] In some embodiments, see Figure 7 As shown, the thickness of at least a portion of the conductive portion 1211 is smaller than the thickness of the transition portion 1212 .

[0464] In some examples, the minimum thickness of the conductive portion 1211 is t1, the thickness of the transition portion 1212 is t2, and t1<t2.

[0465] In some examples, the transition portion 1212 is a structure of equal thickness or substantially equal thickness, the conductive portion 1211 is also a structure of equal thickness or substantially equal thickness, and the thickness of the transition portion 1212 is greater than the minimum thickness of the conductive portion 1211 .

[0466] In some examples, the transition portion 1212 is a structure of equal thickness or a structure of substantially equal thickness, and the conductive portion 1211 may be a structure of unequal thickness. The thickness of the conductive portion 1211 is set to increase in the direction from the conductive portion 1211 to the transition portion 1212. Specifically, the thickness may be increased in steps or slowly. The thickness of the portion of the conductive portion 1211 away from the transition portion 1212 is less than the thickness of the transition portion 1212.

[0467] By adopting the technical solution of this embodiment, the thickness of the transition portion 1212 can be greater than the thickness of at least part of the conductive portion 1211. The large thickness of the transition portion 1212 improves the current flow capacity of the transition portion 1212, reduces the heat generation of the transition portion 1212, reduces the melting risk of the first insulating member 41, and improves the reliability of the battery cell 100. In addition, the current flow capacity of the transition portion 1212 is also improved, which is also beneficial to improving the fast charging performance of the battery cell 100.

[0468] In some embodiments, see Figure 7 As shown, the conductive portion 1211 includes a first sub-portion 12111 and a second sub-portion 12112, the first sub-portion 12111 is connected between the second sub-portion 12112 and the transition portion 1212, the first sub-portion 12111 and the second sub-portion 12112 are covered with an active material layer 20, the thickness of the first sub-portion 12111 is greater than the thickness of the second sub-portion 12112, and the thickness of the transition portion 1212 is greater than or equal to the thickness of the first sub-portion 12111.

[0469] In some examples, the conductive portion 1211 may be a structure of unequal thickness. Along the direction of the conductive portion 1211 pointing to the transition portion 1212, the conductive portion 1211 is divided into two parts. The part close to the transition portion 1212 is the first sub-portion 12111, and the part away from the transition portion 1212 is the second sub-portion 12112. Both the first sub-portion 12111 and the second sub-portion 12112 are covered with an active material layer 20.

[0470] In some examples, the first subsection 12111 may be an equal-thickness structure, and the second subsection 12112 may be an equal-thickness structure; the thickness of the first subsection 12111 is greater than the thickness of the second subsection 12112, and the thickness of the transition section 1212 is greater than or equal to the thickness of the first subsection 12111, the thickness of the first subsection 12111 is t3, and the thickness of the second subsection 12112 is t4, t3>t4, t2≥t3, t1=t4; wherein, the first subsection 12111 and the second subsection 12112 form a step structure; the thickness of the transition section 1212 may be equal to the thickness of the first subsection 12111, so that the transition section 1212 and the first subsection 12111 form an equal-thickness structure; or, the thickness of the transition section 1212 may be greater than the thickness of the second subsection 12112, so that the first subsection 12111 and the transition section 1212 form a step structure.

[0471] In some examples, the first sub-section 12111 may also have a multi-segment structure, with the thickness of each segment increasing in sequence along the direction from the conductive portion 1211 to the transition portion 1212. For example, the first sub-section 12111 includes a first segment and a second segment, with the first segment connected between the second segment and the second sub-section 12112. The thickness of the first segment gradually increases along the direction from the conductive portion 1211 to the transition portion 1212, while the second segment is generally of uniform thickness, with the thickness of the second segment equal to the thickness of the transition portion 1212, i.e., t3 may be equal to the thickness of the second segment. The thickness of the first segment gradually increases from the thickness of the second sub-section 12112 to the thickness of the second segment. This configuration allows the first segment to smoothly transition to the second segment and the second sub-section 12112, thereby reducing stress concentration and improving structural strength. The thickness of the first segment may be equal to the thickness of the transition portion 1212, or the thickness of the transition portion 1212 may be greater than the thickness of the first segment.

[0472] During the use of the battery cell 100, the electrons generated by the active material layer 20 are gradually gathered on the transition part 1212 through the conductive part 1211 along the direction from the conductive part 1211 to the transition part 1212. The electrons flowing through the first sub-part 12111 are more than the electrons flowing through the second sub-part 12112, which requires that the current flow capacity of the first sub-part 12111 is greater than the current flow capacity of the second sub-part 12112.

[0473] The thickness of the first sub-section 12111 in the embodiment of the present application is greater than the thickness of the second sub-section 12112, so that the current flow capacity of the first sub-section 12111 is greater than the current flow capacity of the second sub-section 12112. This can reduce the restriction on the current, improve the current flow capacity of the first pole piece 1, reduce the heat generation of the battery cell 100, and help improve the reliability of the battery cell 100.

[0474] In some embodiments, see Figure 7 As shown, the current collector 10 also includes a conductive protective layer 13, which includes a first protective portion 131 and a second protective portion 132. The first protective portion 131 is located between the first sub-portion 12111 and the active material layer 20, and the second protective portion 132 is located between the second sub-portion 12112 and the active material layer 20; wherein the thickness of the first protective portion 131 is less than the thickness of the second protective portion 132.

[0475] In some examples, along the first direction, the portion of the conductive protection layer 13 located between the first sub-portion 12111 and the active material layer 20 may be the first protection portion 131, and the portion of the conductive protection layer 13 located between the second sub-portion 12112 and the active material layer 20 may be the second protection portion 132, wherein the thickness of the first protection portion 131 is t5, and the thickness of the second protection portion 132 is t6, t5<t6, which can reduce the thickness difference between the current collector 10 at the first protection portion 131 and the second protection portion 132.

[0476] In some examples, the first protection portion 131 may be a structure of equal thickness or unequal thickness, and t5 may be the maximum thickness of the first protection portion 131 ; the second protection portion 132 may be a structure of equal thickness or unequal thickness, and t6 may be the minimum thickness of the second protection portion 132 .

[0477] For example, the first protective portion 131 includes a first portion and a second portion. The first portion is located between the first section and the active material layer 20, and the second protective portion 132 is located between the second sub-portion 12112 and the active material layer 20. The thickness of the first portion gradually decreases along the direction from the conductive portion 1211 to the transition portion 1212, while the second portion has a substantially uniform thickness. This allows the thickness of the first protective portion 131 to match the thickness of the first sub-portion 12111, resulting in a nearly flat surface on the surface of the conductive protective layer 13 facing away from the insulating substrate 11. Here, t5 is equal to the thickness of the second portion.

[0478] 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, it can also reduce the winding bulging problem of the current collector 10.

[0479] In some embodiments, the conductive protection layer 13 further includes a third protection portion 133 . The third protection portion 133 covers the surface of the transition portion 1212 facing away from the insulating base 11 . The thickness of the third protection portion 133 is less than or equal to the thickness of the first protection portion 131 .

[0480] In some examples, along the first direction, the conductive protection layer 13 can be divided into three parts, a part close to the conductive component 30 is the third protection part 133, a part away from the conductive component 30 is the second protection part 132, and the middle part is the first protection part 131, wherein the thickness of the third protection part 133 is t7, t7≤t5<t6; in addition, the thickness of the transition part 1212 is greater than or equal to the thickness of the first sub-part 12111, which can reduce the thickness difference between the current collector 10 at the first protection part 131 and the third protection part 133, which is conducive to the surface of the conductive protection layer 13 facing away from the metal layer 12 being close to the plane.

[0481] For example, the second protective portion 132, the third protective portion 133, the transition portion 1212 and the second sub-portion 12112 are all structures of equal thickness, and the first sub-portion 12111 and the first protective portion 131 are both structures of unequal thickness; the thickness of the first sub-portion 12111 is adapted to the thickness of the first protective portion 131 so that the surface of the conductive protective layer 13 facing away from the insulating substrate 11 is close to a plane.

[0482] By adopting the technical solution of this embodiment, the provision of the third protection portion 133 can make the conductive protection layer 13 protrude from the active material layer 20, so that the active material layer 20 and the metal layer 12 can be better separated. In addition, the thickness of the third protection portion 133 is not too large, which is beneficial to reduce material waste and save the production cost of the battery cell 100.

[0483] In some embodiments, the metal layer 12 also includes at least one protrusion 122, and the transition portion 1212 is connected between the protrusion 122 and the conductive portion 1211; along the second direction, the sum of the sizes of all the protrusions 122 is smaller than the size of the transition portion 1212, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10; the thickness of the protrusion 122 is greater than or equal to the thickness of the transition portion 1212.

[0484] For example, the thickness of the protruding portion 122 may be equal to the thickness of the transition portion 1212 , such that the protruding portion 122 and the transition portion 1212 form a structure of equal thickness.

[0485] For example, the thickness of the protruding portion 122 may also be greater than the thickness of the transition portion 1212 , so that the protruding portion 122 and the transition portion 1212 form a stepped structure.

[0486] By adopting the technical solution of this embodiment, the thickness of the protrusion 122 is larger, which can improve the current flow capacity of the protrusion 122, which is beneficial to improving the current flow capacity of the first pole piece 1, reducing the heat generation of the battery cell 100, and improving the fast charging performance and usage reliability of the battery cell 100.

[0487] The battery cell 100 of the present application is described below in conjunction with some embodiments.

[0488] Example 1

[0489] In this embodiment, see Figures 3 to 12 As shown, the battery cell 100 includes an end cap 201 , a shell 202 and an electrode assembly 101 . The electrode assembly 101 is installed in the shell 202 . The end cap 201 covers the opening of the shell 202 to seal the shell 202 . The end cap 201 is provided with an electrode lead-out portion 2011 .

[0490] In this embodiment, the electrode assembly 101 includes a first electrode plate 1, a second electrode plate 2 and an isolating member 3 which are wound together. The isolating member 3 is located between the first electrode plate 1 and the second electrode plate 2. The polarities of the first electrode plate 1 and the second electrode plate 2 are opposite. The first electrode plate 1 can be a positive electrode plate and the second electrode plate 2 can be a negative electrode plate.

[0491] In this embodiment, the first electrode 1 includes a current collector 10, an active material layer 20 and a conductive component 30. The current collector 10 includes an insulating base 11, a metal layer 12 and a conductive protective layer 13. The two opposite surfaces of the insulating base 11 along the thickness direction are covered with the metal layer 12, the surface of the metal layer 12 facing away from the insulating base 11 is covered with the conductive protective layer 13, and the surface of the conductive protective layer 13 facing away from the insulating base 11 is covered with the active material layer 20.

[0492] In this embodiment, the metal layer 12 includes a main body 121 and at least one protrusion, the main body 121 includes a transition portion 1212 and a conductive portion 1211, the protrusion 122, the transition portion 1212 and the conductive portion 1211 are arranged along a first direction, the transition portion 1212 is connected between the conductive portion 1211 and the protrusion 122, the active material layer 20 covers the conductive portion 1211, the protrusion 122 and the transition portion 1212 are not covered with the active material layer 20, and the first direction is perpendicular to the thickness direction of the current collector 10.

[0493] In this embodiment, both metal layers 12 are welded with conductive components 30, and the conductive components 30 include a first connecting portion 31 and a second connecting portion 32 connected to each other. The first connecting portion 31 is welded to the metal layer 12 to form a first weld mark 51, and the second connecting portions 32 of the two conductive components 30 are welded to form a second weld mark 52.

[0494] In this embodiment, the first weld mark 51 includes a first weld mark portion 511 and a second weld mark portion 512, the first connecting portion 31 includes a first connecting sub-portion 311 and at least one second connecting sub-portion 312, the first connecting sub-portion 311 is connected to the second connecting portion 32 and the second connecting sub-portion 312, the first connecting sub-portion 311 is welded to the transition portion 1212 to form the first weld mark portion 511, and the second connecting sub-portion 312 is welded to the protruding portion 122 to form the second weld mark portion 512.

[0495] In this embodiment, there are a plurality of protrusions 122 , and the protrusions 122 are arranged at intervals along the second direction, which is perpendicular to the first direction and the thickness direction of the current collector 10 .

[0496] In this embodiment, the electrode assembly 101 includes a first insulating member 41 . The first insulating member 41 protrudes from an edge of the first connecting sub-portion 311 away from the active material layer 20 . The first insulating member 41 covers the first weld mark 51 and the second weld mark 52 .

[0497] In this embodiment, the first insulating member 41 includes a first insulating portion 4121 and a plurality of second insulating portions 4122. The first insulating portion 4121 is continuously arranged along the second direction, the first insulating portion 4121 covers the first connecting sub-portion 311, and the plurality of second insulating portions 4122 are connected to the side of the first insulating portion 4121 away from the active material layer 20; the plurality of second insulating portions 4122 are sequentially connected along the second direction to form a whole, the second insulating portions 4122 cover the second connecting sub-portion 312 one by one, and the two adjacent first insulating portions 4121 and the portion corresponding to the area of ​​the first connecting sub-portion 311 where the second connecting sub-portion 312 is not led out form a blocking portion 4131; the blocking portions 4131 of the two second insulating portions 4122 are in contact with each other.

[0498] In this embodiment, the electrode assembly 101 also includes a second insulating member 42, which covers the surface of the transition portion 1212 facing away from the insulating base 11. The second insulating member 42 is located between the first connecting sub-portion 311 and the active material layer 20, and the first insulating member 41 covers the second insulating member 42.

[0499] Example 2

[0500] The difference between this embodiment and the first embodiment is that: Figure 13 As shown, the electrode assembly 101 does not include the second insulating member 42 , one side of the first insulating member 41 covers the first weld mark 51 , and the other side of the first insulating member 41 covers the active material layer 20 .

[0501] Example 3

[0502] The difference between this embodiment and the first embodiment is that: Figure 13 、 Figure 14 and Figure 15 As shown, the first insulating member 41 includes an insulating base layer 4111 and an adhesive layer 4112 , and the adhesive layer 4112 is bonded to the first pole piece 1 .

[0503] In some embodiments, as shown in the figure, a battery device 1100 is provided, including the battery cell 100 of the above embodiment.

[0504] The battery device 1100 of the embodiment of the present application adopts the above-mentioned battery cell 100 . The battery cell 100 has good reliability in use, and the battery device 1100 has good reliability in use.

[0505] In some embodiments, an electrical device is provided, comprising the battery device 1100 according to the above embodiment.

[0506] The electrical device according to the embodiment of the present application adopts the above-mentioned battery device 1100 . The battery device 1100 has good reliability in use, which is beneficial to improving the reliability of the electrical device.

[0507] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0508] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: The housing is provided with an electrode lead portion; an electrode assembly, at least partially housed in the housing, the electrode assembly comprising a first pole piece and a first insulating member, the first pole piece comprising a conductive member, a current collector, and an active material layer, the current collector comprising an insulating substrate and a metal layer; The insulating substrate, the metal layer, and the active material layer are stacked along the thickness direction of the current collector, and at least a portion of the metal layer is located between the insulating substrate and the active material layer; The metal layer includes a main body portion, the main body portion includes a transition portion and a conductive portion arranged and connected along a first direction, the first direction being perpendicular to the thickness direction of the current collector; at least a portion of the conductive portion is covered with the active material layer, and the transition portion is not covered with the active material layer; The conductive component includes a first connecting portion and at least one second connecting portion connected to each other, the first connecting portion is connected to the metal layer, the second connecting portion is electrically connected to the electrode lead portion, the first connecting portion includes a first connecting sub-portion, the first connecting sub-portion covers the surface of the transition portion facing away from the insulating substrate; along the direction of the conductive portion pointing to the transition portion, the first insulating member protrudes from the first connecting sub-portion away from the edge of the active material layer.

2. The battery cell according to claim 1, wherein: Along a direction from the transition portion to the conductive portion, the first insulating member protrudes beyond the first connecting sub-portion close to an edge of the active material layer.

3. The battery cell according to claim 1, wherein: Along the first direction, an edge of the transition portion away from the conductive portion is flush with an edge of the first connecting sub-portion away from the active material layer.

4. The battery cell according to any one of claims 1 to 3, characterized in that: Along the second direction, the size of the conductive portion is L1, the size of the transition portion is L2, 0.8≤L2 / L1≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

5. The battery cell according to any one of claims 1 to 3, characterized in that: The first connection portion is welded to the surface of the metal layer facing away from the insulating substrate to form a first weld mark. Along the first direction, the first weld mark is located on a side of the active material layer close to the transition portion.

6. The battery cell according to claim 5, characterized in that: The first insulating member covers at least a portion of the first weld print.

7. The battery cell according to claim 5, characterized in that: The first weld print includes a first weld print portion, and the first connecting sub-portion is welded to a surface of the transition portion facing away from the insulating base to form the first weld print portion.

8. The battery cell according to claim 7, characterized in that: Along the second direction, the size of the transition portion is L2, the size of the first weld print portion is L3, 0.8≤L3 / L2≤1, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

9. The battery cell according to claim 7, wherein: The first insulating member covers at least a portion of the first weld print.

10. The battery cell according to claim 9, characterized in that: Along the direction from the transition portion to the conductive portion, the first insulating member protrudes beyond the first weld mark and approaches the edge of the active material layer; and / or, along the direction from the conductive portion to the transition portion, the first insulating member protrudes beyond the first weld mark and away from the edge of the active material layer.

11. The battery cell according to claim 7, characterized in that: Along the first direction, an edge of the first weld portion away from the active material layer is flush with an edge of the first connecting sub-portion away from the active material layer.

12. The battery cell according to claim 7, characterized in that: Along the second direction, the two opposite edges of the transition portion are flush with the two opposite edges of the first connecting sub-portion, and the two opposite edges of the first welded portion are flush with the two opposite edges of the first connecting sub-portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

13. The battery cell according to claim 5, characterized in that: The metal layer further includes at least one protruding portion, and the transition portion is connected between the protruding portion and the conductive portion; Along a second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the transition portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; The first connecting portion includes at least one second connecting sub-portion, which is connected between the first connecting sub-portion and the second connecting portion. The second connecting sub-portion covers the surface of the protrusion facing away from the insulating base, and the second connecting sub-portion corresponds to the protrusion one-to-one.

14. The battery cell according to claim 13, characterized in that: The first weld print includes at least one second weld print portion, and the second connecting sub-portion is welded to the corresponding protruding portion to form a second weld print portion.

15. The battery cell according to claim 14, characterized in that: The first insulating member covers at least a portion of the second weld print portion.

16. The battery cell according to claim 15, characterized in that: Along the direction from the transition portion to the conductive portion, the first insulating member protrudes beyond the second weld mark to the edge of the active material layer; and / or, along the direction from the conductive portion to the transition portion, the first insulating member protrudes beyond the second weld mark to the edge of the active material layer.

17. The battery cell according to claim 13, characterized in that: Along the direction from the transition portion to the conductive portion, the first insulating member protrudes from the second connecting sub-portion close to the edge of the active material layer; and / or, along the direction from the conductive portion to the transition portion, the first insulating member protrudes from the second connecting sub-portion away from the edge of the active material layer.

18. The battery cell according to claim 13, wherein: The first insulating member includes a first insulating portion and at least one second insulating portion. The first insulating portion covers the first connecting sub-portion, and the second insulating portion covers the second connecting sub-portion. The second insulating portion corresponds to the second connecting sub-portion in a one-to-one manner.

19. The battery cell according to claim 18, wherein: Along the second direction, at least one of the two opposite sides of the first insulating portion protrudes from a corresponding side surface of the first connecting sub-portion.

20. The battery cell according to claim 18, wherein: There are multiple protrusions, there are multiple second connecting sub-parts, multiple protrusions are arranged at intervals along the second direction, multiple second connecting sub-parts are arranged at intervals along the second direction, multiple protrusions and multiple second connecting sub-parts are arranged in one-to-one correspondence, there are multiple second connecting parts, multiple second connecting parts are arranged at intervals along the second direction, the second connecting sub-parts are connected to the second connecting parts in one-to-one correspondence, and multiple second connecting sub-parts are connected to the edge of the first connecting sub-part facing away from the active material layer; the first connecting sub-parts are continuously arranged along the second direction; there are multiple second insulating parts, multiple second insulating parts are arranged along the second direction, and the second insulating parts are in one-to-one correspondence with the second connecting sub-parts.

21. The battery cell according to claim 20, characterized in that: Two adjacent second insulating parts are connected to each other.

22. The battery cell according to claim 5, characterized in that: Along the first direction, the first weld mark and the active material layer are spaced apart.

23. The battery cell according to claim 22, characterized in that: Along the first direction, a distance between the first weld mark and the active material layer is S1, wherein 0.3 mm ≤ S1 ≤ 5 mm, optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

24. The battery cell according to claim 22, characterized in that The electrode assembly includes a second insulating member, which covers the surface of the metal layer facing away from the insulating substrate, and the entire second insulating member is located between the first weld mark and the active material layer.

25. The battery cell according to claim 24, characterized in that: Along the first direction, the first connecting sub-portion is spaced apart from the active material layer.

26. The battery cell according to claim 25, characterized in that: At least a portion of the second insulating member is located between the first connecting sub-part and the active material layer.

27. The battery cell according to claim 26, characterized in that: The electrode assembly also includes a second pole piece with opposite polarity to the first pole piece, and the second pole piece includes a main functional portion and a pole ear portion arranged along the first direction, the main functional portion has a first end face at an end close to the transition portion, and the pole ear portion extends outward from the first end face; along the thickness direction of the current collector, the projection of the first end face is located within the projection of the second insulating member.

28. The battery cell according to claim 24, wherein: Along the first direction, one side of the first insulating member covers the first connecting sub-portion, and the other side of the first insulating member covers at least a portion of the second insulating member.

29. The battery cell according to any one of claims 1 to 3, characterized in that: Along the first direction, one side of the first insulating member covers the first connecting sub-portion, and the other side of the first insulating member covers at least a portion of the active material layer.

30. The battery cell according to claim 29, wherein: Along the first direction, a size of a portion of the first insulating member covering the active material layer is H, wherein 0.2 mm ≤ H ≤ 1.0 mm, optionally, 0.3 mm ≤ H ≤ 0.8 mm.

31. The battery cell according to any one of claims 1 to 3, characterized in that: The electrode assembly also includes a second pole piece with opposite polarity to the first pole piece, and the second pole piece includes a main functional portion and a pole ear portion arranged along the first direction, the end of the main functional portion close to the transition portion has a first end face, and the pole ear portion extends outward from the first end face; along the direction of the conductive portion toward the transition portion, the side of the first connecting sub-portion away from the active material layer does not protrude from the first end face; or, along the thickness direction of the current collector, the projection of the first end face is located within the projection of the first connecting sub-portion.

32. The battery cell according to any one of claims 1 to 3, characterized in that: The electrode assembly also includes a second pole piece with opposite polarity to the first pole piece, and the second pole piece includes a main functional portion and a pole ear portion arranged along the first direction, the main functional portion has a first end face at an end close to the transition portion, and the pole ear portion extends outward from the first end face; along the thickness direction of the current collector, the projection of the first end face is located within the projection of the first insulating member.

33. The battery cell according to any one of claims 1 to 3, characterized in that: There are two metal layers, which cover opposite sides of the insulating substrate along the thickness direction of the current collector; there are two active material layers, which cover the conductive portions of the two metal layers respectively; There are two conductive members, and the first connecting portions of the two conductive members are connected to the two metal layers respectively; There are two first insulating members, and the two first insulating members respectively cover the first connecting sub-portions of the two conductive components.

34. The battery cell according to claim 33, wherein: Along the direction from the conductive portion to the transition portion, the first insulating member protrudes from the first connecting sub-portion to form a blocking portion, and along the second direction, the blocking portion is located on the side of the second connecting portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

35. The battery cell according to claim 34, characterized in that: The blocking portions of the two first insulating members are in contact with each other.

36. The battery cell according to claim 33, wherein: The second connection portions of the two conductive members are welded to form a second weld mark.

37. The battery cell according to claim 36, characterized in that: The first insulating member covers at least a portion of the second weld mark.

38. The battery cell according to claim 37, characterized in that: Along the direction from the conductive portion to the transition portion, the first insulating member protrudes from an edge of the second weld mark away from the active material layer.

39. The battery cell according to any one of claims 1 to 3, characterized in that: The current collector includes a conductive protective layer, at least a portion of which is located between the active material layer and the conductive portion.

40. The battery cell according to claim 39, wherein: Along the direction from the conductive portion to the transition portion, the conductive protection layer protrudes from the end portion of the active material layer close to the first connecting sub-portion.

41. The battery cell according to claim 40, characterized in that: Along the direction from the conductive portion to the transition portion, the length of the conductive protection layer protruding from the active material layer ranges from 0.3 mm to 0.8 mm.

42. The battery cell according to claim 39, wherein: The first connecting portion is welded to the surface of the metal layer facing away from the insulating substrate to form a first weld mark. Along the first direction, the conductive protective layer and the first weld mark are spaced apart.

43. The battery cell according to any one of claims 1 to 3, characterized in that: The first insulating member is connected to the first pole piece.

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

45. The battery cell according to claim 44, characterized in that: The thickness of the insulating base layer is in the range of 6 μm to 15 μm; and / or the thickness of the adhesive layer is in the range of 0.5 μm to 3 μm.

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

47. The battery cell according to any one of claims 1 to 3, characterized in that: The thickness of at least a portion of the conductive portion is smaller than the thickness of the transition portion.

48. The battery cell according to claim 47, characterized in that: The conductive portion includes a first sub-portion and a second sub-portion, the first sub-portion is connected between the second sub-portion and the transition portion, the first sub-portion and the second sub-portion are covered with the active material layer, the thickness of the first sub-portion is greater than the thickness of the second sub-portion, and the thickness of the transition portion is greater than or equal to the thickness of the first sub-portion.

49. The battery cell according to claim 48, characterized in that: The current collector also includes a conductive protective layer, which includes a first protective portion and a second protective portion, wherein the first protective portion is located between the first sub-portion and the active material layer, and the second protective portion is located between the second sub-portion and the active material layer; wherein the thickness of the first protective portion is less than the thickness of the second protective portion.

50. The battery cell according to claim 49, wherein: The conductive protection layer further includes a third protection portion, which covers a surface of the transition portion facing away from the insulating substrate, and a thickness of the third protection portion is less than or equal to a thickness of the first protection portion.

51. The battery cell according to any one of claims 1 to 3, characterized in that: The metal layer further includes at least one protruding portion, and the transition portion is connected between the protruding portion and the conductive portion; Along a second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the transition portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; The thickness of the protruding portion is greater than or equal to the thickness of the transition portion.

52. A battery device, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 51.

53. An electrical device, characterized in that: A battery device comprising the battery device of claim 52.

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