Battery monomer, battery device and electric device

Abstract

The utility model belongs to the technical field of battery insulation, and particularly relates to a single battery, a battery device and a power utilization device.The single battery comprises a shell and an electrode assembly arranged in the shell, and the shell is provided with an electrode leading-out part; the electrode assembly comprises a first pole piece, the first pole piece comprises a current collector, a conductive component and an active substance layer, and the conductive component is connected with the electrode leading-out part; the current collector comprises an insulating substrate and a metal layer, the insulating substrate, the metal layer and the active material layer are stacked in the thickness direction of the current collector, and the metal layer is located between the insulating substrate and the active material layer; the metal layer comprises a first metal part and a second metal part which extends outwards from the end part of the first metal part along the first direction; the first metal part is covered with an active material layer, and the second metal part is not covered with the active material layer; the conductive component is welded to the second metal part and forms a first welding mark; and the first pole piece further comprises an insulating part, and the insulating part comprises a first insulating part covering the first welding mark, so that the use reliability of the single battery can be improved.

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 insulation 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] In a first aspect, in some embodiments, a battery cell is provided, which 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 arranged in the shell, the electrode assembly includes a first pole piece, the first pole piece includes a current collector, a conductive component and an active material layer, and the conductive component is electrically connected to the electrode lead-out portion; the current collector includes an insulating base and a metal layer, the insulating base, 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 base and the active material layer; the metal layer includes a first metal part and a second metal part arranged and connected along a first direction, and the first direction is perpendicular to the thickness direction of the current collector; at least a portion of the first metal part is covered with the active material layer, and at least a portion of the second metal part is not covered with the active material layer; the conductive component is welded to the surface of the second metal part facing away from the insulating base and forms a first weld mark; the electrode assembly includes a first insulating member, and the first insulating member covers at least a portion of the first weld mark.

[0009] By adopting the technical solution of this embodiment, the first insulating member covers at least a portion of the first weld mark, and the first insulating member can block the burrs of the first weld mark, thereby reducing the short circuit risk of the battery cell, and is beneficial to improving the reliability of the battery cell; the current collector adopts a composite structure of an insulating substrate and a metal layer. Compared with a pure metal current collector, the metal layer has a smaller thickness, and the burrs generated by the current collector during the manufacturing process are smaller, thereby reducing the internal short circuit risk of the battery cell, and is beneficial to improving the reliability of the battery cell.

[0010] In some embodiments, the first insulating member protrudes from the edge of the first weld mark away from the active material layer along the direction from the first metal portion to the second metal portion; and / or, the first insulating member protrudes from the edge of the first weld mark close to the active material layer along the direction from the second metal portion to the first metal portion.

[0011] By adopting the technical solution of this embodiment, the first insulating member can block the burrs at the edges of the first weld mark that are relatively distributed along the first direction, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0012] In some embodiments, the conductive component includes a first connecting portion and at least one second connecting portion, the first connecting portion is connected to the second connecting portion, the second connecting portion is electrically connected to the electrode lead portion, and the first connecting portion is welded to the surface of the second metal portion facing away from the insulating substrate to form a first weld mark.

[0013] By adopting the technical solution of this embodiment, the provision of the second connecting portion can facilitate the connection between the second connecting portion and the electrode lead-out portion, making the production of the battery cell more convenient.

[0014] In some embodiments, the second metal part includes at least one protrusion; along the second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the first metal part, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector; the first connecting part includes at least one first connecting sub-part, the first connecting sub-part is connected to the second connecting part, the first connecting sub-part covers the surface of the protrusion facing away from the insulating substrate, and the first connecting sub-part corresponds to the protrusion one-to-one.

[0015] By adopting the technical solution of this embodiment, along the second direction, the size of all the protrusions is smaller than that of the first metal part. The small size of the protrusions along the second direction can save space and is conducive to improving the volume energy density of the battery cell.

[0016] In some embodiments, the first insulating member includes at least one first insulating portion, the first insulating portion covers a surface of the first connecting sub-portion facing away from the protruding portion, and the first connecting sub-portions correspond to each other one-to-one.

[0017] By adopting the technical solution of this embodiment, the first insulating portion covers the first connecting sub-portion, thereby achieving insulation of the first connecting sub-portion, which is beneficial to reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0018] In some embodiments, the first weld print includes at least one first weld print portion, the first connecting sub-portion is welded to the surface of the protrusion facing away from the insulating base to form the first weld print portion; the first insulating portion covers at least a portion of the first weld print portion.

[0019] By adopting the technical solution of this embodiment, the first connecting sub-part is welded to the protruding part to achieve connection between the first connecting sub-part and the protruding part, which has a simple structure and is easy to manufacture; the first insulating part can block burrs on the first weld print part, reduce the risk of short circuit of the battery cell, and improve the reliability of the battery cell.

[0020] In some embodiments, the protrusion includes a first protruding sub-portion and a second protruding sub-portion, the first protruding sub-portion is connected between the second protruding sub-portion and the first metal portion; along the second direction, the size of the first protruding sub-portion is larger than the size of the second protruding sub-portion; the first weld portion includes a first weld sub-portion, the first connecting portion is welded to the first protruding sub-portion and forms the first weld sub-portion, and the first insulating portion covers at least a portion of the first weld sub-portion; and / or, the first weld portion includes a second weld sub-portion, the first connecting portion is welded to the second protruding sub-portion and forms the second weld sub-portion, and the first insulating portion covers at least a portion of the second weld sub-portion.

[0021] By adopting the technical solution of this embodiment, along the second direction, the size of the first protruding sub-portion is large, which is beneficial to increasing the welding area between the first protruding sub-portion and the first connecting portion, increasing the flow area between the protruding portion and the first connecting portion, improving the flow capacity between the protruding portion and the first connecting portion, reducing the heat generation of the battery cell, and improving the fast charging performance and use reliability of the battery cell; along the second direction, the size of the second protruding sub-portion is small relative to the size of the first protruding sub-portion, which is beneficial to reducing the space occupied by the protruding portion and improving the energy density of the battery cell.

[0022] In some embodiments, along the direction from the first metal portion to the second metal portion, the first insulating portion protrudes from the edge of the first weld print portion away from the active material layer; and / or, along the direction from the second metal portion to the first metal portion, the first insulating portion protrudes from the edge of the first weld print portion close to the active material layer.

[0023] By adopting the technical solution of this embodiment, the first insulating portion can block the burrs at the edge of the first weld mark, reduce the short circuit risk of the battery cell, and improve the reliability of the battery cell.

[0024] In some embodiments, along the second direction, two opposite side surfaces of the protruding portion are flush with two opposite side surfaces of the corresponding first connecting sub-portion, and two opposite edges of the first welding portion are flush with two opposite side surfaces of the corresponding first connecting sub-portion.

[0025] By adopting the technical solution of this embodiment, along the second direction, the two opposite side surfaces of the protrusion are respectively flush with the two opposite side surfaces of the corresponding first connecting sub-part, the structure is regular, and the processing and manufacturing are convenient. In addition, it can also reduce redundancy, save space, and improve the energy density of the battery cell; along the second direction, the first weld portion extends from one side of the first connecting sub-part to the other side of the second connecting sub-part. Along the second direction, the size of the first weld portion is large, which is conducive to increasing the welding area between the protrusion and the first connecting part, increasing the flow area between the protrusion and the first connecting part, improving the flow capacity, reducing the heat generation of the battery cell, and improving the fast charging performance and reliability of the battery cell.

[0026] In some embodiments, along the second direction, at least one of the two opposite side portions of the first insulating portion protrudes beyond a side surface of the corresponding first connecting sub-portion located on the same side.

[0027] By adopting the technical solution of this embodiment, the first insulating portion can block the pointed protrusions at the sides of the first connecting sub-portion relatively distributed along the second direction, reducing the short circuit risk of the battery cell and helping to improve the reliability of the battery cell.

[0028] In some embodiments, along the direction from the first metal part to the second metal part, the first insulating part protrudes from the side of the corresponding first connecting sub-part away from the active material layer; and / or, along the direction from the second metal part to the first metal part, the first insulating part protrudes from the side of the corresponding first connecting sub-part close to the active material layer.

[0029] By adopting the technical solution of this embodiment, the first insulating part can cover the side of the first connecting sub-part close to and / or away from the active material layer, block the burrs on the side of the first connecting sub-part close to and / or away from the active material layer, and reduce the short circuit risk of the battery cell.

[0030] In some embodiments, there are multiple protrusions, the first connection part includes multiple first connection sub-parts, the multiple protrusions are arranged at intervals along the second direction, and the multiple first connection sub-parts are arranged at intervals along the second direction; there are multiple second connection parts, the multiple second connection parts are arranged at intervals along the second direction, and the first connection sub-parts are connected one-to-one with the second connection parts.

[0031] By adopting the technical solution of this embodiment, multiple protrusions are arranged at intervals along the second direction, which is conducive to dividing the first metal part into multiple regions along the second direction, and one 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 first metal part. The electron transmission path in each region to the corresponding protrusion is short, which is conducive to reducing the transmission distance of electrons, reducing the overall resistance of the first electrode sheet, and improving the fast charging performance and usage reliability of the battery cell.

[0032] In some embodiments, two adjacent first insulating portions are disconnected or connected.

[0033] By adopting the technical solution of this embodiment, two adjacent first insulating parts are arranged at intervals, which can save space and is conducive to improving the energy density of the battery cell; the two adjacent first insulating parts can be directly connected to form an integral structure, which can facilitate the installation of the first insulating parts; at the same time, the first insulating part can also cover the opposite side surfaces of the first connecting sub-part along the second direction, blocking the tip protrusions at the opposite side surfaces of the first connecting sub-part along the second direction, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0034] In some embodiments, the second metal portion includes a transition portion and at least one protrusion, the transition portion being connected between the protrusion and the first metal portion; along the second direction, a size of the transition portion is greater than the sum of sizes of all protrusions, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0035] By adopting the technical solution of this embodiment, the transition part has a large size along the second direction, so that the transition part can have a larger area to connect with the first connecting part, so that the electrons of the first metal part and the active material layer can flow directly to the first connecting part through the transition part, which can reduce the overcurrent pressure between the protrusion and the transition part, reduce the heat at the connection between the protrusion and the transition part, and improve the fast charging performance of the battery cell.

[0036] In some embodiments, along the second direction, a dimension of the first metal portion is L1, a dimension of the transition portion is L2, and 0.8≤L2 / L1≤1.

[0037] By adopting the technical solution of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition part large along the second direction, which is beneficial to increasing the connection area between the first connection part and the transition part, improving the flow capacity of the connection between the first connection part and the transition part, 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.

[0038] In some embodiments, the first weld print includes a second weld print portion, the first connecting portion includes a second connecting sub-portion connected to the second connecting portion, and the second connecting sub-portion is welded to the transition portion to form the second weld print portion.

[0039] By adopting the technical solution of this embodiment, the surface of the transition part facing away from the insulating base is welded to the first connecting part, so that a part of the current can directly flow into or out of the first connecting part through the transition part, reducing the overcurrent pressure between the protrusion and the transition part, which is beneficial to reducing the heat generation at the connection between the protrusion and the transition part, and improving the fast charging performance of the battery cell.

[0040] In some embodiments, along the second direction, a dimension of the transition portion is L2, a dimension of the second weld print portion is L3, and 0.8≤L3 / L2≤1.

[0041] By adopting the technical solution of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the second weld portion along the second direction larger, which is beneficial to increasing the connection area between the second connecting sub-portion and the transition portion, improving the flow capacity of the connection between the second 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.

[0042] In some embodiments, the side of the transition portion facing away from the first metal portion, the edge of the second weld portion away from the active material layer, and the side of the second connector portion facing away from the active material layer are flush.

[0043] By adopting the technical solution of this embodiment, the second weld portion, the second connecting sub-portion and the transition portion have regular structures and are easy to process and manufacture. In addition, the redundancy of the second connecting sub-portion and the transition portion can be reduced, space can be saved, and the energy density of the battery cell can be improved.

[0044] In some embodiments, the first insulating member includes a second insulating portion, and the second insulating portion covers at least a portion of the second weld print portion.

[0045] By adopting the technical solution of this embodiment, the second insulating portion can block the burrs on the second weld print portion, reducing the short circuit risk of the battery cell, which is conducive to improving the reliability of the battery cell.

[0046] In some embodiments, along the direction from the first metal portion to the second metal portion, the second insulating portion protrudes from the second weld print portion away from the edge of the active material layer; and / or, along the direction from the second metal portion to the first metal portion, the second insulating portion protrudes from the second weld print portion close to the edge of the active material layer.

[0047] By adopting the technical solution of this embodiment, the second insulating portion can block the burrs at the edges of the second weld print portion that are relatively distributed along the first direction, reducing the short circuit risk of the battery cell and helping to improve the reliability of the battery cell.

[0048] In some embodiments, along the direction from the first metal portion to the second metal portion, the second insulating portion protrudes from a side of the second connecting sub-portion away from the active material layer.

[0049] By adopting the technical solution of this embodiment, the second insulating part can block burrs, metal debris and other components on the side of the second connecting sub-part facing away from the active material layer, reducing the risk of short circuit in the battery cell and helping to improve the reliability of the battery cell.

[0050] In some embodiments, along the second direction, two opposite side surfaces of the transition portion are flush with two opposite side surfaces of the second connecting sub-portion, and two opposite edges of the second weld portion are flush with two opposite side surfaces of the second connecting sub-portion.

[0051] By adopting the technical solution of this embodiment, the edge structure of the first pole piece relatively distributed along the second direction is regular, which can facilitate the processing and production of the first pole piece, and can also reduce the redundancy of the second connecting sub-portion and the transition portion, save space, and improve the energy density of the battery cell; in addition, along the second direction, the size of the second weld portion is equal to the size of the transition portion, and the first weld portion extends from one side of the transition portion along the second direction to the other side. The welding area between the transition portion and the first connecting sub-portion is large, which is conducive to improving the current flow capacity of the first pole piece and improving the fast charging performance of the battery cell.

[0052] In some embodiments, along the second direction, at least one of the two opposite sides of the second insulating portion protrudes beyond a corresponding side surface of the second connecting sub-portion.

[0053] By adopting the technical solution of this embodiment, the second insulating portion can block the burrs on the side of the second 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.

[0054] In some embodiments, along the direction from the first metal portion to the second metal portion, the second insulating portion protrudes from the side of the second connecting sub-portion facing away from the active material layer; and / or, along the direction from the second metal portion to the first metal portion, the second insulating portion protrudes from the side of the second connecting sub-portion facing toward the active material layer.

[0055] By adopting the technical solution of this embodiment, the second insulating portion blocks the burrs on the side surfaces of the second connecting sub-portion that are relatively distributed along the first direction, 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, the first connecting portion includes at least one first connecting sub-portion, the first connecting sub-portion is connected between the second connecting portion and the second connecting sub-portion, the first connecting sub-portion covers the surface of the protrusion facing away from the insulating base, and the first connecting sub-portion corresponds one-to-one to the protrusion; the first insulating part includes at least one first insulating portion, the first insulating portion is connected to the second insulating portion, the first insulating portion covers the surface of the first connecting sub-portion facing away from the protrusion, and the first insulating portion corresponds one-to-one to the first connecting sub-portion.

[0057] By adopting the technical solution of this embodiment, the first insulating part covers the first connecting sub-part, the second insulating part covers the second connecting sub-part, and the first insulating part covers the first connecting sub-part and the second connecting sub-part. The coverage area of ​​the first insulating part is large, and the insulating effect of the first insulating part is good, which reduces the short circuit risk of the battery cell and improves the reliability of the battery cell.

[0058] In some embodiments, there are multiple protrusions, and the multiple protrusions are arranged at intervals along the second direction; there are multiple first connecting sub-parts, and the multiple first connecting sub-parts are arranged at intervals along the second direction; there are multiple second connecting parts, and the multiple second connecting parts are arranged at intervals along the second direction; the first connecting sub-parts are connected to the second connecting parts in a one-to-one correspondence, and the multiple first connecting sub-parts are connected to the side of the second connecting sub-parts facing away from the active material layer; the second connecting sub-parts are continuously arranged along the second direction.

[0059] By adopting the technical solution of this embodiment, the second connecting sub-part is continuously arranged along the second direction, and multiple first connecting sub-parts can be connected into a whole. The second connecting sub-part can play a good supporting role for the first connecting sub-part, which can reduce the risk of the first connecting sub-part being bent and inserted between the first pole piece and the second pole piece, reduce the short circuit risk of the battery cell, and help improve the reliability of the battery cell; in addition, along the second direction, the size of the second connecting sub-part is large, which is conducive to increasing the welding area between the second connecting sub-part and the transition part, which is conducive to improving the flow capacity of the connection between the first connecting sub-part and the transition part, improving the flow capacity of the first pole piece, and improving the fast charging performance and reliability of the battery cell.

[0060] 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 main functional portion has a first end face at an end close to the second metal portion, and the pole ear portion extends outward from the first end face; along the direction from the first metal portion toward the second metal portion, the side of the second 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 second connecting sub-portion.

[0061] By adopting the technical solution of this embodiment, the side of the second connecting sub-part away from the active material layer does not protrude from the first end face, so that the first end face is arranged opposite to the hollow area of ​​the conductive component, which can reduce the short circuit risk of the battery cell and is beneficial to improving the reliability of the battery cell; along the thickness direction of the current collector, the projection of the first end face is located within the projection of the second connecting sub-part, so that the side of the second connecting sub-part facing away from the active material layer is not arranged opposite to the main functional part, which can reduce the short circuit risk of the battery cell and is beneficial to improving the reliability of the battery cell.

[0062] In some embodiments, the first insulating member protrudes from a side of the first connecting portion away from the active material layer along the direction from the first metal portion to the second metal portion; and / or, the first insulating member protrudes from a side of the first connecting portion close to the active material layer along the direction from the second metal portion to the first metal portion.

[0063] By adopting the technical solution of this embodiment, the first insulating part can cover the side surfaces of the first connecting portion that are relatively distributed along the first direction, and can block burrs, metal debris and other components on the side surfaces of the first connecting portion that are relatively distributed along the first direction, 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, the first weld mark is spaced apart from the active material layer.

[0065] 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 poor welding between the first connecting part and the metal layer, and improving the reliability of the battery cell.

[0066] In some embodiments, the electrode assembly further includes a second insulating member, the second insulating member covering a surface of the second metal portion facing away from the insulating substrate, and the second insulating member is located between the first weld mark and the active material layer.

[0067] 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.

[0068] In some embodiments, along the first direction, the first connecting portion is spaced apart from the active material layer.

[0069] By adopting the technical solution of this embodiment, the first connecting portion does not contact the active material layer, which can reduce the mutual influence between the two and is conducive to improving the performance of the battery cell.

[0070] In some embodiments, at least a portion of the second insulating member is located between the first connecting portion and the active material layer.

[0071] By adopting the technical solution of this embodiment, the second insulating member covers the portion of the second metal part located between the connecting portion 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 second metal part located between the first connecting portion 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.

[0072] 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 a first direction, the main functional portion has a first end face at an end close to the second metal 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.

[0073] In some embodiments, along the first direction, one side of the first insulating member covers the first weld mark, and the other side of the first insulating member covers at least a portion of the second insulating member.

[0074] 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.

[0075] In some embodiments, the second insulating member includes a first phase-change heat storage layer, and the first phase-change heat storage layer covers a surface of the second metal portion facing away from the insulating substrate.

[0076] By adopting the technical solution of this embodiment, during the charging and discharging process of the battery cell, the first phase change heat storage layer can absorb the heat of the second metal part, lower the temperature of the second metal part, and reduce the risk of cracks and breakage of the second metal part, which is beneficial to improving the electron transmission capacity of the second metal part and improving the fast charging performance and usage reliability of the battery cell.

[0077] In some embodiments, the first phase-change heat storage layer includes an organic heat storage material layer or an inorganic heat storage material layer.

[0078] By adopting the technical solution of this embodiment, the first phase change heat storage layer is made of an organic heat storage material. The organic heat storage material has good cycle stability and thermal stability, which is conducive to maintaining the stable structural form of the second insulating member, improving the stability of the second insulating member fixed on the second metal part, reducing the risk of the second insulating member falling off, and improving the reliability of the battery cell; the first phase change heat storage layer is made of an inorganic heat storage material. The inorganic heat storage material has a strong heat storage capacity, which is conducive to reducing the temperature of the second metal part and improving the reliability of the battery cell. In addition, the cost of the inorganic heat storage material is low, which is conducive to reducing the production cost of the battery cell.

[0079] In some embodiments, the first phase change heat storage layer includes an organic heat storage material layer, and the organic heat storage material layer includes a fatty acid layer, a paraffin layer, a linear alkane layer, a fatty alcohol layer, or an ester material layer.

[0080] By adopting the technical solution of this embodiment, the organic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell, the first phase change heat storage layer can better absorb the heat of the second metal part, reduce the temperature of the second metal part, and improve the reliability of the battery cell. In addition, the first phase change heat storage layer can also maintain a stable structural form, reduce the risk of the second insulating part falling off, and is conducive to improving the reliability of the battery cell.

[0081] In some embodiments, the first phase change heat storage layer includes an inorganic heat storage material layer, and the inorganic heat storage material layer includes a nitrate layer, a carbonate layer, a fluoride salt layer, or a hydrochloride layer.

[0082] By adopting the technical solution of this embodiment, the inorganic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell, the first phase change heat storage layer can better absorb the heat of the second metal part, reduce the temperature of the second metal part, and improve the reliability of the battery cell. In addition, the first phase change heat storage layer can also maintain a stable structural form, reduce the risk of the second insulating part falling off, and is conducive to improving the reliability of the battery cell.

[0083] In some embodiments, along the first direction, one side of the first insulating member covers the first weld mark, and the other side of the first insulating member covers the active material layer.

[0084] By adopting the technical solution of this embodiment, the first insulating member extends from the first weld mark to the active material layer. The first insulating member has a wide coverage area and a good insulation effect, which is beneficial to improving the reliability of the battery cell.

[0085] 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 first metal 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 welded to the second metal parts of the two metal layers to form two first weld marks; the number of first insulating parts is two, and the two first insulating parts respectively cover the two first weld marks.

[0086] 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 connecting 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.

[0087] In some embodiments, along the direction pointing from the first metal part to the second metal part, the portion of the first insulating member protruding from the metal layer 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.

[0088] By adopting the technical solution of this embodiment, the blocking portion can block burrs, metal debris and other components at the edge of the metal layer, reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0089] In some embodiments, the blocking portions of the two first insulating members are in contact with each other.

[0090] By adopting the technical solution of this embodiment, after the blocking parts of the two first insulating parts are bonded together, burrs, metal debris and other components on the edge of the metal layer can be wrapped, 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.

[0091] In some embodiments, the second connection portions of the two conductive members are welded to form a second weld mark.

[0092] 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.

[0093] In some embodiments, the first insulating member covers at least a portion of the second weld mark.

[0094] By adopting the technical solution of this embodiment, the first insulating member can cover the second weld mark, thereby 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.

[0095] In some embodiments, along a direction from the first metal portion toward the second metal portion, the first insulating member protrudes beyond an edge of the second weld mark away from the active material layer.

[0096] 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.

[0097] 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 a first direction, the main functional portion has a first end face at an end close to the second metal 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.

[0098] 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.

[0099] In some embodiments, the glass transition temperature of the first insulating member is greater than or equal to 150°C. Optionally, the glass transition temperature of the first insulating member is greater than or equal to 200°C.

[0100] By adopting the technical solution of this embodiment, during the charging and discharging process of the battery cell, the first insulating part can maintain a stable structural form, reducing the risk of melting of the first insulating part, reducing the risk of exposure of burrs, metal debris and other components on the first weld mark, reducing the short circuit risk of the battery cell, and improving the reliability of the battery cell.

[0101] In some embodiments, the specific heat capacity of the first insulating member is greater than or equal to 1.2 J / g·°C.

[0102] By adopting the technical solution of this embodiment, the specific heat capacity of the first insulating member is designed to be greater than or equal to 1.2 J / g·°C. Therefore, during the charge and discharge process of the battery cell, the first insulating member can absorb the heat at the first weld mark, thereby reducing the temperature of the first weld mark. In addition, the temperature rise of the first insulating member is small, thereby reducing the risk of melting of the first insulating member. The first insulating member can stably block the burrs of the first weld mark, thereby reducing the short circuit risk of the battery cell and improving the reliability of the battery cell.

[0103] In some embodiments, the first insulating member includes a first insulating base layer and a first adhesive layer, and the first adhesive layer is bonded between the first weld print and the first insulating base layer.

[0104] By adopting the technical solution of this embodiment, the first insulating member adopts the structure of a tape, and the first insulating member can be directly attached to the first weld mark, reducing the risk of missing coverage; the first insulating base layer and the first adhesive layer cover the first weld mark to block the burrs of the first weld mark, and the thickness of the first insulating base layer and the thickness of the first adhesive layer do not need to be set large, which is beneficial to improving the energy density of the battery cell; the first insulating base layer has good structural strength, which can stably block the burrs of the first weld mark and improve the reliability of the battery cell; the first adhesive layer can stably fix the first insulating base layer on the first weld mark, reducing the risk of the first insulating member falling off; metal debris of the first weld mark can also be adhered to the first adhesive layer, which can effectively reduce the risk of metal debris of the first weld mark falling off and reduce the short circuit risk of the battery cell.

[0105] In some embodiments, the first insulating member further includes a second phase change heat storage layer, the second phase change heat storage layer is connected between the first insulating base layer and the first adhesive layer, and the first adhesive layer is bonded between the second phase change heat storage layer and the first weld print.

[0106] By adopting the technical solution of this embodiment, the second phase change heat storage layer can be used to absorb the heat at the first weld mark during the phase change process, thereby reducing the temperature rise of the first insulating base layer and the first adhesive layer, and reducing the risk of melting of the first insulating base layer and the first adhesive layer, which is beneficial to maintaining the structural stability of the first insulating part and improving the reliability of the battery cell.

[0107] In some embodiments, the second phase-change heat storage layer includes an organic heat storage material layer or an inorganic heat storage material layer.

[0108] By adopting the technical solution of this embodiment, the second phase change heat storage layer is made of organic heat storage material. The organic heat storage material has good cycle stability and thermal stability, which is conducive to maintaining the stable structural form of the first insulating member, improving the stability of the first insulating member fixed on the first weld mark, reducing the risk of the first insulating member falling off, and improving the reliability of the battery cell; the second phase change heat storage layer is made of inorganic heat storage material. The inorganic heat storage material has a strong heat storage capacity, which is conducive to reducing the temperature at the first weld mark and improving the reliability of the battery cell. In addition, the cost of the inorganic heat storage material is low, which is conducive to reducing the production cost of the battery cell.

[0109] In some embodiments, the second phase-change heat storage layer includes an organic heat storage material layer, and the organic heat storage material layer includes a fatty acid layer, a paraffin layer, a linear alkane layer, a fatty alcohol layer, or an ester material layer.

[0110] By adopting the technical solution of this embodiment, the organic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell, the second phase change heat storage layer can better absorb the heat at the first weld mark, reduce the temperature rise of the first insulating base layer and the first adhesive layer, which is beneficial for the first insulating base layer to maintain a stable structural form, and can stably block burrs, metal debris and other components on the first weld mark, reduce the risk of the first insulating component falling off, and improve the reliability of the battery cell.

[0111] In some embodiments, the second phase-change heat storage layer includes an inorganic heat storage material layer, and the inorganic heat storage material layer includes a nitrate layer, a carbonate layer, a fluoride salt layer, or a hydrochloride layer.

[0112] By adopting the technical solution of this embodiment, the inorganic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell, the second phase change heat storage layer can better absorb the heat at the first weld mark, reduce the temperature rise of the first insulating base layer and the first adhesive layer, which is beneficial for the first insulating base layer to maintain a stable structural form, and can stably block burrs, metal debris and other components on the first weld mark, reduce the risk of the first insulating component falling off, and improve the reliability of the battery cell.

[0113] In some embodiments, the second phase-change heat storage layer has a thickness ranging from 1 μm to 5 μm.

[0114] By adopting the technical solution of this embodiment, the design of the second phase change heat storage layer having a thickness greater than or equal to 1 μm enables the second phase change heat storage layer to absorb heat at the first weld mark, reduce the temperature at the first weld mark, and is beneficial to maintaining the mechanical strength and structural stability of the first insulating member, and improving the reliability of the battery cell; the design of the second phase change heat storage layer having a thickness less than or equal to 5 μm is beneficial to reducing the space and weight occupied by the phase change heat storage, and is beneficial to improving the energy density of the battery cell.

[0115] In some embodiments, the glass transition temperature of the first adhesive layer is greater than the phase change temperature of the second phase change heat storage layer, and / or the glass transition temperature of the first insulating base layer is greater than the phase change temperature of the second phase change heat storage layer.

[0116] By adopting the technical solution of this embodiment, when the second phase change heat storage layer absorbs heat and undergoes phase change, the first insulating member can maintain a stable structural form, which is beneficial to maintaining the mechanical strength and structural stability of the first insulating member, reducing the risk of insulation failure of the first insulating member, and improving the reliability of the battery cell.

[0117] In some embodiments, the first insulating base layer includes a polypropylene layer, a polyethylene terephthalate layer, a aramid 1313 layer, a polyvinylidene fluoride layer, or a cellulose layer.

[0118] By adopting the technical solution of this embodiment, the first insulating base layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell, the first insulating base layer can maintain a stable structural form and is not prone to melting. The first insulating component has good high temperature resistance, which is conducive to improving the reliability of the battery cell.

[0119] In some embodiments, the first adhesive layer includes a latex acrylic layer, an ethylene acrylic acid copolymer layer, a latex layer, or a latex layer.

[0120] By adopting the technical solution of this embodiment, the first adhesive layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell, the first adhesive layer can maintain a stable structural form and is not prone to melting. The first insulating part can be stably bonded to the first weld mark, reducing the risk of the first insulating part falling off, which is beneficial to improving the reliability of the battery cell.

[0121] In some embodiments, the first adhesive layer has a thickness ranging from 1 μm to 7 μm.

[0122] By adopting the technical solution of this embodiment, the design of the thickness of the first adhesive layer being greater than or equal to 1 μm enables the first adhesive layer to stably bond the second phase change heat storage layer and the first weld print together, reduces the risk of the first insulating part falling off, and improves the reliability of the battery cell; the design of the thickness of the first adhesive layer being less than or equal to 7 μm can reduce the risk of glue overflow in the first adhesive layer.

[0123] In some embodiments, the first insulating base layer has a thickness ranging from 1 μm to 10 μm.

[0124] By adopting the technical solution of this embodiment, the design of the first insulating base layer having a thickness greater than or equal to 1 μm enables the first insulating base layer to better block the burrs of the first weld mark, thereby improving the reliability of the battery cell; the design of the first insulating base layer having a thickness less than or equal to 10 μm reduces the space occupied and weight of the first insulating base layer, which is conducive to improving the energy density of the battery cell.

[0125] In some embodiments, the current collector further includes a conductive protection layer, at least a portion of which is located between the active material layer and the first metal part.

[0126] By adopting the technical solution of this embodiment, the conductive protective layer can separate the active material layer and the metal layer, play a protective role on the metal layer, reduce the risk of cracks in the metal layer caused by rolling the active material layer, and help improve the current carrying capacity of the metal layer.

[0127] In some embodiments, along a direction from the first metal portion toward the second metal portion, the conductive protection layer protrudes from an end portion of the active material layer close to the second metal portion.

[0128] 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.

[0129] In some embodiments, at least a portion of the first metal portion has a thickness smaller than a thickness of the second metal portion.

[0130] By adopting the technical solution of this embodiment, the thickness of the second metal part can be greater than the thickness of at least part of the first metal part. The large thickness of the second metal part improves the current-carrying capacity of the second metal part, reduces the heat generation of the second metal 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-carrying capacity of the second metal part, which is also beneficial to improving the fast charging performance of the battery cell.

[0131] In some embodiments, the first metal part includes a first sub-part and a second sub-part, the first sub-part is connected between the second sub-part and the second metal part, the first sub-part and the second sub-part are covered with an active material layer, the thickness of the first sub-part is greater than the thickness of the second sub-part, and the thickness of the second metal part is greater than or equal to the thickness of the first sub-part.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] In some embodiments, the conductive protection layer further includes a third protection portion, the third protection portion covers a surface of the second metal 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.

[0136] 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.

[0137] In a second aspect, a battery device is provided, comprising the battery cell of the above embodiment.

[0138] 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.

[0139] In a third aspect, a battery device is provided, comprising the battery cell of the above embodiment.

[0140] 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.

[0141] 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

[0142] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions 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.

[0143] Figure 1 A schematic structural diagram of a vehicle provided for some embodiments of the present application.

[0144] Figure 2 This is a schematic exploded view of a battery device provided in some embodiments of the present application.

[0145] Figure 3 Schematic diagram of an exploded view of a battery cell provided in some embodiments of the present application.

[0146] Figure 4 A schematic structural diagram of the electrode assembly provided in some embodiments of the present application.

[0147] Figure 5 For the Figure 4 Sectional view along line AA.

[0148] Figure 6Schematic 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.

[0149] Figure 7 For the Figure 6 Sectional view along the midline BB.

[0150] 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.

[0151] Figure 9 for Figure 8 A partial enlarged view of point C in the middle.

[0152] Figure 10 for Figure 8 The diagram shows the structure of the first pole piece hiding the second insulating member and the conductive component.

[0153] Figure 11 for Figure 10 A partial enlarged view of point D in the middle.

[0154] Figure 12 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.

[0155] Figure 13 Schematic diagram of the structure of the first pole piece and the second insulating member provided in some embodiments of the present application.

[0156] Figure 14 for Figure 13 A partial enlarged view of point F in the middle.

[0157] Figure 15 A schematic diagram of the structure of the first pole piece after hiding the conductive component provided in some embodiments of the present application.

[0158] Figure 16 for Figure 15 A partial enlarged view of point G in the middle.

[0159] Figure 17 The first pole piece, the first insulating member and the second insulating member provided in some embodiments of the present application are arranged along Figure 6 Sectional view along the midline BB.

[0160] Figure 18 For the Figure 12 Sectional view along line EE.

[0161] Figure 19 A schematic structural diagram of the first insulating member provided in some embodiments of the present application.

[0162] Figure 20 For the Figure 19 Sectional view along the midline HH.

[0163] Figure 21 The first insulating member provided in some embodiments of the present application is along Figure 19 Sectional view along the midline HH.

[0164] Among them, the reference numerals in the figures are:

[0165] 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, first metal portion; 1211, first sub-portion; 1212, second sub-portion; 122, second metal portion; 1221, transition portion; 1222, protrusion; 12221, first protrusion sub-portion; 12222, second protrusion sub-portion; 13, conductive protective layer; 131, first protective portion; 132, second protective portion; 133, third protective portion; 20, active material layer; 30, conductive member; 31, first connecting portion; 311, first connecting sub-portion; 312, second connecting sub-portion; 32. Second connecting portion; 41. First insulating member; 4111. First insulating base layer; 4112. First adhesive layer; 4113. Second phase-change heat storage layer; 4121. First insulating portion; 4122. Second insulating portion; 4131. Blocking portion; 42. Second insulating member; 51. First weld mark; 511. First weld mark portion; 5111. First weld mark sub-portion; 5112. Second weld mark sub-portion; 512. Second weld mark portion; 52. Second weld mark; 2. Second pole piece; 210. Main functional portion; 2101. First end face; 220. Pole ear portion; 3. Isolator; 200. Shell; 201. End cover; 2011. Electrode lead portion; 202. Shell; 300. Box; 301. First box portion; 302. Second box portion. DETAILED DESCRIPTION

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0175] 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.

[0176] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal battery cells. Polygonal battery cells are, for example, hexagonal battery cells.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] In some embodiments, the battery device may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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 is thinner, 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 welded with a conductive component and electrically connected to the electrode lead-out part of the battery cell through the conductive component, thereby realizing the input or output of electrical energy of the battery cell; the conductive component and the metal layer are welded to form a weld mark, and the weld mark is prone to burrs. The burrs have the risk of piercing the diaphragm and causing a short circuit in the battery cell, affecting the reliability of the battery cell.

[0188] Based on this, an embodiment of the present application provides a technical solution, in which the metal layer of the battery cell is welded to the conductive component to form a first weld mark, and at least part of the first weld mark is covered with a first insulating member. The first insulating member is used to block the burrs on the first weld mark, thereby reducing the risk of short circuit in the battery cell and improving the reliability of the battery cell.

[0189] The battery cells described in the embodiments of the present application are applicable to battery devices and electrical devices using the battery devices.

[0190] 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.

[0191] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0192] 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.

[0193] 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.

[0194] 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 .

[0195] 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.

[0196] 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 .

[0197] 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 .

[0198] 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.

[0199] 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.

[0200] For example, a battery cell may be the smallest unit constituting the battery device 1100 .

[0201] 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.

[0202] The housing 200 is used to encapsulate the electrode assembly 101 and components such as the electrolyte.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] The end cover 201 is connected to the housing 202 by welding, bonding, clamping or other methods.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] In some embodiments, the gel electrolyte includes a polymer as an electrolyte skeleton network and an ionic liquid-lithium salt.

[0217] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, or a composite solid electrolyte.

[0218] 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.

[0219] 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.

[0220] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.).

[0226] 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.).

[0227] 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.

[0228] 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.).

[0229] 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.

[0230] 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] In some embodiments, the electrode assembly 101 is a laminated structure.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] 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 .

[0241] 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.

[0242] In some embodiments, the shape of the electrode assembly 101 can be cylindrical, flat, or polygonal.

[0243] Please also refer to Figures 6-9As 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 provided in the shell 200, the electrode assembly 101 includes a first pole piece 1, the first pole piece 1 includes a current collector 10, a conductive member 30 and an active material layer 20, the conductive member 30 is electrically connected to the electrode lead-out portion 2011; the current collector 10 includes an insulating substrate 11 and a metal layer 12, the insulating substrate 11, the metal layer 12 and the active material layer 20 are stacked along the thickness direction of the current collector 10, and at least a portion of the metal layer 12 is provided. The metal layer 12 includes a first metal portion 121 and a second metal portion 122 arranged and connected along a first direction, and the first direction is perpendicular to the thickness direction of the current collector 10; at least a portion of the first metal portion 121 is covered with the active material layer 20, and at least a portion of the second metal portion 122 is not covered with the active material layer 20; the conductive member 30 is welded to the surface of the second metal portion 122 facing away from the insulating substrate 11 and forms a first weld mark 51; the electrode assembly 101 includes a first insulating member 41, and the first insulating member 41 covers at least a portion of the first weld mark 51.

[0244] 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 .

[0245] 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 structure, and the active material layer 20 is a positive electrode active material layer; 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 structure, and the active material layer 20 is a negative electrode active material layer.

[0246] 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 .

[0247] 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.

[0248] The electrode lead-out portion 2011 is electrically connected to the conductive component 30, and the electrode lead-out portion 2011 can be directly connected to the conductive component 30; for example, the electrode lead-out portion 2011 is directly welded to the conductive component 30; or, the electrode lead-out portion 2011 can be connected to the conductive component 30 through a conductive member (for example, an adapter, etc.), for example, one end of the conductive member is welded to the conductive component 30, and the other end of the conductive member is welded to the electrode lead-out portion 2011.

[0249] 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.

[0250] 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 7 The 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.

[0251] In some examples, a surface of the insulating substrate 11 is covered with a metal layer 12 .

[0252] In some examples, two opposite surfaces of the insulating base 11 are covered with metal layers 12 , and among the two metal layers 12 , a surface of at least one metal layer 12 facing away from the insulating base 11 is covered with an active material layer 20 .

[0253] 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.

[0254] 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).

[0255] 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 from the first metal portion 121 to the second metal portion 122 can be referred to in FIG. Figure 7 The positive direction of the Z direction; the direction of the second metal portion 122 pointing to the first metal portion 121 can be referred to Figure 7 The negative Z direction.

[0256] In some examples, along the first direction, the metal layer 12 is divided into two parts, the part covered with the active material layer 20 is the first metal part 121, and the part not covered with the active material layer 20 is the second metal part 122. The first metal part 121 has a uniform width structure, and the second metal part 122 can be a structure with the same width as the first metal part 121. The second metal part 122 can also be a protruding structure provided on one side of the first metal part 121, or other structures. The interface between the first metal part 121 and the second metal part 122 can refer to the end surface of the active material layer 20 close to the second metal part 122 (see Figure 7 The end portion of the active material layer 20 near the second metal portion 122 may be thinned to reduce the roller pressure applied to the end portion of the active material layer 20 near the second metal portion 122 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 second metal portion 122 may be a plane or may be approximately a straight line.

[0257] In some examples, the conductive member 30 and the electrode lead portion 2011 can be electrically connected to each other by welding or using conductive adhesive.

[0258] In some examples, the conductive component 30 is welded to the surface of the second metal part 122 facing away from the insulating base 11. Compared with the conductive component 30 welded to the end face of the second metal part 122 facing away from the first metal part 121, the surface area of ​​the second metal part 122 facing away from the insulating base 11 is larger, which is beneficial to increase the welding area between the conductive component 30 and the second metal part 122, improve the flow area between the conductive component 30 and the second metal part 122, improve the flow capacity of the first pole piece 1, and improve the fast charging performance of the battery cell 100.

[0259] A weld mark formed by welding the conductive member 30 to the surface of the second metal portion 122 facing away from the insulating base 11 is a first weld mark 51 .

[0260] The electrode assembly 101 includes a first insulating member 41, which covers the surface of the conductive component 30 facing away from the second metal part 122 and covers the first weld mark 51. The first insulating member 41 can cover a portion of the first weld mark 51 or the entire first weld mark 51. The first insulating member 41 can block the burrs of the first weld mark 51, thereby reducing the risk of the burrs of the first weld mark 51 piercing the isolation member 3 and contacting the second electrode 2, reducing the short circuit risk of the battery cell 100, and helping to improve the reliability of the battery cell 100.

[0261] 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.

[0262] In some examples, the first insulating member 41 may be fixed to the first weld mark 51 by bonding or static adsorption.

[0263] By adopting the technical solution of this embodiment, the first insulating member 41 covers at least a portion of the first weld mark 51. The first insulating member 41 can block the burrs of the first weld mark 51, reduce the short circuit risk of the battery cell 100, and help improve the reliability of the battery cell 100. The current collector 10 adopts a composite structure of an insulating substrate 11 and a metal layer 12. Compared with the current collector 10 of pure metal, the thickness of the metal layer 12 is small, and the burrs generated by the current collector 10 during the manufacturing process are small, which reduces the internal short circuit risk of the battery cell 100 and helps improve the reliability of the battery cell 100.

[0264] In some embodiments, see Figure 7 、 Figure 8 and Figure 9 As shown, the conductive component 30 includes a first connecting portion 31 and at least one second connecting portion 32. The first connecting portion 31 is welded to the surface of the second metal portion 122 facing away from the insulating substrate 11 and forms a first weld mark 51. The second connecting portion 32 is connected to the side of the first connecting portion 31 facing away from the active material layer 20. The second connecting portion 32 is electrically connected to the electrode lead portion 2011.

[0265] The first connection portion 31 may refer to a portion where the conductive member 30 is welded to the second metal portion 122 , and the second connection portion 32 may refer to a portion where the conductive member 30 is connected to the electrode lead-out portion 2011 .

[0266] In some examples, the first connection portion 31 may cover the second metal portion 122 and be welded to the second metal portion 122, the second connection portion 32 may extend from the side of the first connection portion 31 facing away from the active material layer 20 along the first direction and away from the active material layer 20, the second connection 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 connection portion 31 is located within the projection of the second metal portion 122, and the projection of the second connection portion 32 is located outside the projection range of the second metal portion 122, the first connection portion 31 and the second connection portion 32 are divided based on the end face of the second metal portion 122 facing away from the first metal portion 121; the second metal portion 122 and the electrode lead portion 2011 have different connection positions on the conductive component 30, which is convenient for connection and can also reduce the mutual influence between the two connections, which is beneficial to connection reliability.

[0267] In some examples, the first connection portion 31 is stacked on the surface of the second metal portion 122 facing away from the insulating base 11 and welded to the surface of the second metal portion 122 facing away from the insulating base 11 . The weld mark formed by the welding is the first weld mark 51 .

[0268] 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.

[0269] 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 the two adjacent layers of the metal layer 12 are not easily directly connected across the insulating substrate 11 and transmit 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; while the battery cell 100 of the embodiment of the present application utilizes the first connecting portion 31 of the conductive member 30 to be welded to the second metal portion 122, and the second connecting portion 32 of the conductive member 30 protrudes out of the insulating substrate 11, so that the second connecting portion 32 can be used 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.

[0270] In some examples, when the electrode sheets are stacked to form the electrode assembly 101, the insulating substrate 11 insulates and separates the two adjacent metal layers 12, making it difficult for the two adjacent metal layers 12 to directly connect across the insulating substrate 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 and low fast charging performance. It is also easy to cause local overheating, affecting the reliability of the battery cell 100. In the battery cell 100 of the embodiment of the present application, the first connecting portion 31 of the conductive member 30 is welded to the second metal portion 122, and the second connecting portion 32 of the conductive member 30 protrudes from the insulating substrate 11. In this way, the second connecting portion 32 can be used to electrically connect the two adjacent metal layers 12, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast charging performance of the battery cell 100, reducing the heat generation of the battery cell 100, and improving the reliability of the battery cell 100.

[0271] By adopting the technical solution of this embodiment, the provision of the second connecting portion 32 can facilitate the connection between the second connecting portion 32 and the electrode lead-out portion 2011 , making the manufacture of the battery cell 100 more convenient.

[0272] In some embodiments, see Figures 8-11 As shown, the second metal part 122 includes at least one protrusion 1222; along the second direction, the sum of the sizes of all the protrusions 1222 is smaller than the size of the first metal part 121, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10; the first connecting part 31 includes at least one first connecting sub-part 311, the first connecting sub-part 311 is connected to the second connecting part 32, and the first connecting sub-part 311 covers the surface of the protrusion 1222 facing away from the insulating base 11, and the first connecting sub-part 311 corresponds one-to-one to the protrusion 1222.

[0273] The protrusion 1222 may refer to a protruding structure formed on the edge of the metal layer 12, so that the edge of the metal layer 12 is a step structure, and the number of protrusions 1222 may be one or more; the number of protrusions 1222 is one, and along the second direction, the size of the protrusion 1222 is smaller than the size of the first metal part 121; the number of protrusions 1222 is multiple, and multiple protrusions 1222 are spaced apart along the second direction, and along the second direction, the sum of the sizes of all the protrusions 1222 is smaller than the size of the first metal part 121.

[0274] In some examples, along the second direction, the size of the protrusion 1222 is l1, the size of the first metal part 121 is L1, and the number of the protrusions 1222 is N, wherein the number of the protrusions 1222 is 1, l1<L1; the number of the protrusions 1222 is multiple, and the multiple protrusions 1222 adopt the same structure, N*l1<L1.

[0275] In some examples, the second metal portion 122 includes only the protrusion 1222 , and the protrusion 1222 may be a protruding structure directly extending from the edge of the first metal portion 121 .

[0276] In some examples, the second metal portion 122 includes a protrusion 1222 and another portion (eg, a transition portion 1221 ) connected between the protrusion 1222 and the first metal portion 121 . The protrusion 1222 extends outward from a side of the portion facing away from the first metal portion 121 .

[0277] The first connecting sub-portion 311 may refer to the portion of the first connecting portion 31 covering the surface of the protrusion 1222 facing away from the insulating base 11 ; in some examples, 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 protrusion 1222 .

[0278] In some examples, the number of the protrusions 1222 is the same as the number of the first connecting sub-portions 311 , and the first connecting sub-portions 311 cover the protrusions 1222 in a one-to-one correspondence.

[0279] By adopting the technical solution of this embodiment, along the second direction, the size of all the protrusions 1222 is smaller than that of the first metal part 121 . The small size of the protrusions 1222 along the second direction can save space, which is beneficial to improving the volume energy density of the battery cell 100 .

[0280] In some embodiments, see Figures 7-11 As shown, the first insulating member 41 includes at least one first insulating portion 4121 . The first insulating portion 4121 covers the surface of the first connecting sub-portion 311 facing away from the protruding portion 1222 . The first connecting sub-portions 311 correspond to each other one by one.

[0281] The first insulating portion 4121 may refer to the portion of the first insulating member 41 covering the first connecting sub-portion 311 ; the first insulating portion 4121 may cover a portion of the first connecting sub-portion 311 or the entire first connecting sub-portion 311 .

[0282] In some examples, the number of the first insulating portions 4121 is the same as the number of the first connecting sub-portions 311 , and the first insulating portions 4121 and the first connecting sub-portions 311 are provided in a one-to-one correspondence.

[0283] By adopting the technical solution of this embodiment, the first insulating portion 4121 covers the first connecting sub-portion 311 , thereby achieving insulation of the first connecting sub-portion 311 , which is beneficial for reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100 .

[0284] In some embodiments, see Figures 7-11As shown, the first weld mark 51 includes at least one first weld mark portion 511 , the first connecting sub-portion 311 is welded to the surface of the protrusion 1222 facing away from the insulating base 11 to form the first weld mark portion 511 ; the first insulating portion 4121 covers at least part of the first weld mark portion 511 .

[0285] The first weld mark portion 511 may refer to a weld mark formed by welding the first connecting sub-portion 311 and the protruding portion 1222 .

[0286] The first insulating portion 4121 may cover a portion of the first weld print portion 511 , or the first insulating portion 4121 may cover the entire first weld print portion 511 .

[0287] During the production of some first pole pieces 1, the conductive component 30 can be welded to the edge of the equal-length current collector 10 by ultrasonic welding (for example, double-roller continuous ultrasonic welding) or other welding methods to form an equal-width weld mark, and then the conductive component 30 is cut by laser die-cutting or other cutting methods to form a pole ear to facilitate connection with the electrode lead-out portion 2011; and in the cutting process, first cutting is performed along the second direction at a position between the equal-width weld mark and the active material layer 20, and then cutting is performed toward the equal-width weld mark until it leaves the equal-width weld mark, and then cutting is continued for a distance away from the active material layer 20, and then cutting is continued for a distance along the second direction, and then cutting is performed in the direction toward the equal-width weld mark until it leaves the equal-width weld mark, and then cutting is performed along the second direction, so that a first weld mark portion 511 can be obtained. After multiple cuttings, multiple first weld marks 511 can be obtained.

[0288] By adopting the technical solution of this embodiment, the first connecting sub-portion 311 is welded to the protrusion 1222 to achieve the connection between the first connecting sub-portion 311 and the protrusion 1222, which has a simple structure and is easy to manufacture; the first insulating portion 4121 can block the burrs on the first weld portion 511, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0289] In some embodiments, see Figures 7-11 As shown, the protrusion 1222 includes a first protruding sub-portion 12221 and a second protruding sub-portion 12222, and the first protruding sub-portion 12221 is connected between the second protruding sub-portion 12222 and the first metal portion 121; along the second direction, the size of the first protruding sub-portion 12221 is larger than the size of the second protruding sub-portion 12222; the first weld portion 511 includes a first weld sub-portion 5111, the first connecting portion 31 is welded to the first protruding sub-portion 12221 and forms the first weld sub-portion 5111, and the first insulating portion 4121 covers at least a portion of the first weld sub-portion 5111.

[0290] The protrusion 1222 has a step structure. Along the first direction, the protrusion 1222 is divided into two parts, the part close to the first metal part 121 is the first protruding sub-part 12221, and the part away from the first metal part 121 is the second protruding sub-part 12222; along the second direction, the size of the first protruding sub-part 12221 is l2, and the size of the second protruding sub-part 12222 is l3, l2>l3, which is equivalent to increasing the size of the first protruding sub-part 12221 along the second direction, increasing the flow area between the protrusion 1222 and the first metal part 121, 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.

[0291] The first connection portion 31 is welded to the surface of the first protruding sub-portion 12221 facing away from the insulating base 11 , and a weld mark produced by the welding is a first weld mark sub-portion 5111 .

[0292] The first insulating portion 4121 may cover a portion of the first weld sub-portion 5111 , or may cover the entire first weld sub-portion 5111 .

[0293] By adopting the technical solution of this embodiment, along the second direction, the size of the first protruding sub-portion 12221 is large, which is conducive to increasing the welding area between the first protruding sub-portion 12221 and the first connecting portion 31, increasing the flow area between the protruding portion 1222 and the first connecting portion 31, improving the flow capacity between the protruding portion 1222 and the first connecting portion 31, reducing the heat generation of the battery cell 100, and improving the fast charging performance and use reliability of the battery cell 100; along the second direction, the size of the second protruding sub-portion 12222 is small relative to the size of the first protruding sub-portion 12221, which is conducive to reducing the space occupied by the protruding portion 1222, and improving the energy density of the battery cell 100; the first insulating portion 4121 covers at least a portion of the first weld sub-portion 5111, and the first insulating portion 4121 can block the burrs of the first weld sub-portion 5111, which is conducive to improving the use reliability of the battery cell 100.

[0294] In some embodiments, see Figures 7-11 As shown, the first weld portion 511 includes a second weld sub-portion 5112 , the first connection portion 31 is welded to the second protruding sub-portion 12222 to form the second weld sub-portion 5112 , and the first insulating portion 4121 covers at least a portion of the second weld sub-portion 5112 .

[0295] The second protruding portion 12222 is welded to the first connecting portion 31 on the surface facing away from the insulating base 11, and the weld mark formed by the welding is the second weld mark portion 5112. The first insulating portion 4121 may cover a portion of the second weld mark portion 5112 or the entire second weld mark portion 5112.

[0296] By adopting the technical solution of this embodiment, the second protruding sub-portion 12222 is welded to the first connecting portion 31, thereby realizing a welded connection between the protruding portion 1222 and the first connecting portion 31; the first insulating portion 4121 covers at least a portion of the second weld sub-portion 5112, and the first insulating portion 4121 can block the burrs of the second weld sub-portion 5112, which is beneficial to improving the reliability of the battery cell 100.

[0297] In some embodiments, see Figures 7-11 As shown, the first weld print portion 511 includes a first weld print sub-portion 5111, the first connecting portion 31 is welded to the first protruding sub-portion 12221 and forms the first weld print sub-portion 5111, and the first insulating portion 4121 covers at least a portion of the first weld print sub-portion 5111; the first weld print portion 511 includes a second weld print sub-portion 5112, the first connecting portion 31 is welded to the second protruding sub-portion 12222 and forms the second weld print sub-portion 5112, and the first insulating portion 4121 covers at least a portion of the second weld print sub-portion 5112.

[0298] By adopting the technical solution of this embodiment, the first protruding sub-portion 12221 and the second protruding sub-portion 12222 are both welded to the first connecting portion 31, thereby increasing the welding area between the first connecting portion 31 and the protruding portion 1222, increasing the current flow capacity between the first connecting portion 31 and the protruding portion 1222, and improving the fast charging performance of the battery cell 100; in addition, the first insulating portion 4121 covers the first weld sub-portion 5111 and the second weld sub-portion 5112, and the first insulating portion 4121 can block the burrs of the first weld sub-portion 5111 and the burrs of the second weld sub-portion 5112, thereby reducing the short circuit risk of the battery cell 100 and helping to improve the reliability of the battery cell 100.

[0299] In some embodiments, see Figures 7-11 As shown, along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating portion 4121 protrudes from the edge of the first weld print 511 away from the active material layer 20 .

[0300] 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 is located within the projection of the first insulating portion 4121 .

[0301] In some examples, along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating portion 4121 protrudes from an edge of the first weld print 511 that is farthest from the active material layer 20 .

[0302] In some examples, the first weld print portion 511 only includes the first weld sub-portion 5111 , and along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating portion 4121 protrudes from the edge of the first weld sub-portion 5111 away from the active material layer 20 .

[0303] In some examples, the first weld print portion 511 only includes the second weld sub-portion 5112 , and along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating portion 4121 protrudes from the second weld sub-portion 5112 away from the edge of the active material layer 20 .

[0304] In some examples, the first weld print portion 511 includes a first weld print sub-portion 5111 and a second weld print sub-portion 5112. The first weld print sub-portion 5111 and the second weld print sub-portion 5112 can be directly connected to each other, that is, the first weld print sub-portion 5111 and the second weld print sub-portion 5112 can be a whole weld print; of course, the first weld print sub-portion 5111 and the second weld print sub-portion 5112 can also be arranged at intervals; along the direction from the first metal portion 121 to the second metal portion 122, the first insulating portion 4121 protrudes from the edge of the second weld print sub-portion 5112 away from the active material layer 20.

[0305] In some examples, the first weld print portion 511 includes a first weld sub-portion 5111 and a second weld sub-portion 5112 . Along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating portion 4121 may also protrude from the edge of the first weld sub-portion 5111 away from the active material layer 20 .

[0306] By adopting the technical solution of this embodiment, the first insulating portion 4121 covers the edge of the first weld mark 51 away from the active material layer 20. The first insulating portion 4121 can block the burrs at the edge of the first weld mark 51 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.

[0307] In some embodiments, see Figures 7-11 As shown, along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating portion 4121 protrudes from the edge of the first weld print 511 close to the active material layer 20 .

[0308] 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 is located within the projection of the first insulating portion 4121 .

[0309] In some examples, along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating portion 4121 protrudes beyond the edge of the first weld print 511 closest to the active material layer 20 .

[0310] In some examples, the first weld print portion 511 only includes the first weld sub-portion 5111 , and along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating portion 4121 protrudes from the edge of the first weld sub-portion 5111 close to the active material layer 20 .

[0311] In some examples, the first weld print portion 511 only includes the second weld sub-portion 5112 , and along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating portion 4121 protrudes from the edge of the second weld sub-portion 5112 close to the active material layer 20 .

[0312] In some examples, the first weld print portion 511 includes a first weld print sub-portion 5111 and a second weld print sub-portion 5112. The first weld print sub-portion 5111 and the second weld print sub-portion 5112 can be directly connected to each other or can be arranged at intervals, along the direction of the second metal portion 122 pointing to the first metal portion 121, and the first insulating portion 4121 protrudes from the edge of the first weld print sub-portion 5111 close to the active material layer 20.

[0313] In some examples, the first weld print portion 511 includes a first weld sub-portion 5111 and a second weld sub-portion 5112 , and the first insulating portion 4121 protrudes from the edge of the second weld sub-portion 5112 near the active material layer 20 along the direction from the second metal portion 122 to the first metal portion 121 .

[0314] By adopting the technical solution of this embodiment, the first insulating portion 4121 covers the edge of the first weld mark 51 close to the active material layer 20. The first insulating portion 4121 can block the burrs at the edge of the first weld mark 51 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.

[0315] In some embodiments, see Figures 7-11 As shown, along the direction from the first metal part 121 to the second metal part 122, the first insulating part 4121 protrudes from the edge of the first weld print 511 away from the active material layer 20; along the direction from the second metal part 122 to the first metal part 121, the first insulating part 4121 protrudes from the edge of the first weld print 511 close to the active material layer 20.

[0316] 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 portion 4121 , and 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 portion 4121 .

[0317] In some examples, along the thickness direction of the current collector 10 , the projection of the first weld print 511 is located within the projection of the first insulating portion 4121 , so as to achieve full coverage of the first weld print 511 .

[0318] By adopting the technical solution of this embodiment, along the first direction, the opposite sides of the first insulating portion 4121 can protrude from the opposite edges of the first weld print portion 511. The first insulating portion 4121 has a large coverage area, effectively blocks burrs on the first weld print portion 511, reduces the short circuit risk of the battery cell 100, and improves the reliability of the battery cell 100.

[0319] In some embodiments, see Figures 7-11 As shown, along the second direction, the two opposite side surfaces of the protruding portion 1222 are flush with the two opposite side surfaces of the corresponding first connecting sub-portion 311 , and the two opposite edges of the first welding portion 511 are flush with the two opposite side surfaces of the corresponding first connecting sub-portion 311 .

[0320] In the second direction, the protrusion 1222 overlaps with the corresponding connecting sub-section, and the size of the protrusion 1222 is the same as the size of the corresponding first connecting sub-section 311. The size of the first connecting sub-section 311 is the same as the size of the corresponding first weld stamp 511. In the second direction, the first weld stamp 511 extends from one side of the corresponding first connecting sub-section 311 to the other side of the first connecting sub-section 311.

[0321] In some examples, the protrusion 1222 includes a first protruding sub-portion 12221 and a second protruding sub-portion 12222. Along the second direction, the first connecting sub-portion 311 covers the first protruding sub-portion 12221 on two opposite side surfaces, respectively, and is flush with the two opposite side surfaces of the first protruding sub-portion 12221. The first welding sub-mark extends from one side of the first protruding sub-portion 12221 to the other side of the first protruding sub-portion 12221. Along the second direction, the first connecting sub-portion 311 covers the second protruding sub-portion 12222 on two opposite side surfaces, respectively, and is flush with the two opposite side surfaces of the second protruding sub-portion 12222. The second welding sub-mark extends from one side of the second protruding sub-portion 12222 to the other side of the second protruding sub-portion 12222.

[0322] During the production process of some first pole pieces 1, the protrusion 1222, the first connecting portion 31 and the second connecting portion 32 are obtained by cutting, and along the second direction, the opposite side surfaces of the protrusion 1222, the opposite side surfaces of the corresponding first connecting sub-portion 311 and the opposite edges of the first weld print portion 511 are obtained by cutting, so that along the second direction, the opposite side surfaces of the protrusion 1222 are respectively flush with the opposite side surfaces of the corresponding first connecting sub-portion 311, and the opposite edges of the first weld print portion 511 are respectively flush with the opposite side surfaces of the corresponding first connecting sub-portion 311.

[0323] By adopting the technical solution of this embodiment, along the second direction, the two opposite side surfaces of the protrusion 1222 are respectively flush with the two opposite side surfaces of the corresponding first connecting sub-portion 311, the structure is regular, and the processing and manufacturing are convenient. In addition, it can also reduce redundancy, save space, and improve the energy density of the battery cell 100; along the second direction, the first weld stamp 511 extends from one side of the first connecting sub-portion 311 to the other side of the second connecting sub-portion 312. Along the second direction, the size of the first weld stamp 511 is large, which is conducive to increasing the welding area between the protrusion 1222 and the first connecting portion 31, increasing the flow area between the protrusion 1222 and the first connecting portion 31, improving the flow capacity, reducing the heat generation of the battery cell 100, and improving the fast charging performance and reliability of the battery cell 100.

[0324] In some embodiments, see Figure 7 As shown, along the second direction, at least one of the two opposite sides of the first insulating portion 4121 protrudes from the side surface of the corresponding first connecting sub-portion 311 located on the same side.

[0325] Along the second direction, one side of the first insulating portion 4121 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 of the first insulating portion 4121 protrudes from or does not protrude from the other side surface of the first connecting sub-portion 311 .

[0326] In some battery cells 100, after the first connecting sub-portion 311 is cut, a pointed protrusion may be generated on the side of the first connecting sub-portion 311 along the second direction. The distance between the first connecting sub-portion 311 and the active material layer 20 is relatively close, and the distance between the first connecting sub-portion 311 and the second electrode 2 is relatively close. The pointed protrusion may overlap with the second electrode 2, thereby causing a short circuit in the battery cell 100; in particular, along the second direction, the two opposite edges of the first weld print 511 are obtained by cutting, and a large pointed protrusion may be generated on the edge of the first weld print 511; and along the second direction, the side of the first insulating portion 4121 protrudes beyond the corresponding edge of the first weld print 511, which can block the pointed protrusion and better improve the reliability of the battery cell 100.

[0327] By adopting the technical solution of this embodiment, the first insulating portion 4121 can block the pointed protrusions at the sides of the first connecting sub-portion 311 relatively distributed along the second direction, reducing the short circuit risk of the battery cell 100 and helping to improve the reliability of the battery cell 100.

[0328] In some embodiments, along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating portion 4121 protrudes from a side of the corresponding first connecting sub-portion 311 away from the active material layer 20 .

[0329] Along the thickness direction of the current collector 10 , the projection of the side surface of the first connector 311 away from the active material layer 20 falls within the projection of the first insulating portion 4121 .

[0330] In some examples, the side of the first connecting sub-portion 311 away from the active material layer 20 can refer to the interface between the first connecting sub-portion 311 and the second connecting portion 32. The interface between the second connecting sub-portion 312 and the second connecting portion 32 can refer to the end surface of the protrusion 1222 facing away from the first metal portion 121 (see Figure 7 The first insulating portion 4121 protrudes from the interface between the first connecting portion 311 and the second connecting portion 32 , and the first insulating portion 4121 can extend to the second connecting portion 32 .

[0331] In some examples, a portion of the first insulating portion 4121 may cover a partial area of ​​the second connecting portion 32 close to the first connecting sub-portion 311 or cover the entire first connecting sub-portion 311, and another portion of the first insulating portion 4121 may cover a partial area of ​​the second connecting portion 32 close to the first connecting sub-portion 311, and a partial area of ​​the second connecting portion 32 away from the first connecting sub-portion 311 is not covered by the first insulating portion 4121, so as to facilitate electrical connection between the partial area of ​​the second connecting portion 32 away from the first connecting sub-portion 311 and the electrode lead-out portion 2011.

[0332] In some examples, when the first weld mark 511 is covered with the first insulating portion 4121, the first insulating portion 4121 can cover the edge of the first weld mark 51 away from the active material layer 20. The first insulating portion 4121 can block the burrs at the edge of the first weld mark 51 close to the active material layer 20, thereby reducing the short circuit risk of the battery cell 100.

[0333] By adopting the technical solution of this embodiment, the first insulating portion 4121 can extend from the first weld mark 51 to the second connection portion 32, so that the first insulating portion 4121 can cover the edge of the first weld mark 51 facing away from the active material layer 20. The first insulating member 41 can block the burrs at the edge of the first weld mark 511 facing away from the active material layer 20, thereby reducing the short circuit risk of the battery cell 100; in addition, the first insulating portion 4121 can cover at least a portion of the second connection portion 32, thereby achieving insulation of at least a portion of the second connection portion 32, which is beneficial to reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0334] In some embodiments, along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating portion 4121 protrudes from a side of the corresponding first connecting sub-portion 311 close to the active material layer 20 .

[0335] Along the thickness direction of the current collector 10 , the projection of the side surface of the first connecting sub-portion 311 close to the active material layer 20 falls within the projection of the corresponding first insulating portion 4121 .

[0336] In some examples, along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating portion 4121 protrudes from a side surface of the first connecting sub-portion 311 close to the active material layer 20 .

[0337] In some examples, when the first weld mark 511 is covered with the first insulating portion 4121, the first insulating portion 4121 can cover the edge of the first weld mark 51 close to the active material layer 20. The first insulating portion 4121 can block the burrs at the edge of the first weld mark 51 close to the active material layer 20, thereby reducing the short circuit risk of the battery cell 100.

[0338] By adopting the technical solution of this embodiment, the first insulating part 4121 can cover the side of the first connecting sub-part 311 close to the active material layer 20, block the burrs on the side of the first connecting sub-part 311 close to the active material layer 20, and reduce the short circuit risk of the battery cell 100.

[0339] In some embodiments, see Figures 7-11 As shown, along the direction from the second metal part 122 to the first metal part 121, the first insulating part 4121 protrudes from the side of the corresponding first connecting sub-part 311 close to the active material layer 20, and along the direction from the second metal part 122 to the first metal part 121, the first insulating part 4121 protrudes from the side of the corresponding first connecting sub-part 311 close to the active material layer 20.

[0340] In the first direction, two opposite sides of the first insulating portion 4121 protrude from two opposite side surfaces of the first connecting sub-portion 311 .

[0341] In some examples, the first connecting sub-portion 311 is welded to the protrusion 1222 to form a first weld print portion 511. In the first direction, the first insulating portion 4121 can cover the entire first weld print portion 511. The first insulating portion 4121 can block the burrs at the edge of the first weld print 511 close to the active material layer 20, thereby reducing the short circuit risk of the battery cell 100.

[0342] By adopting the technical solution of this embodiment, in the first direction, the first insulating portion 4121 can completely cover the first connecting sub-portion 311, thereby improving the insulation effect of the first connecting sub-portion 311, which is beneficial to reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0343] In some embodiments, see Figures 7-11As shown, there are multiple protrusions 1222, the first connection part 31 includes multiple first connection sub-parts 311, the multiple protrusions 1222 are arranged at intervals along the second direction, and the multiple first connection sub-parts 311 are arranged at intervals along the second direction; there are multiple second connection parts 32, the multiple second connection parts 32 are arranged at intervals along the second direction, and the first connection sub-parts 311 are connected one-to-one with the second connection parts 32.

[0344] When there are multiple protrusions 1222, the multiple protrusions 1222 are spaced apart along the second direction, each protrusion 1222 is correspondingly covered with a first connecting sub-portion 311, each first connecting sub-portion 311 is correspondingly connected to a second connecting portion 32, the multiple second connecting portions 32 are spaced apart along the second direction, and each first connecting sub-portion 311 is correspondingly covered with a first insulating portion 4121. After the electrode sheet is wound, the multiple protrusions 1222 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.

[0345] By adopting the technical solution of this embodiment, multiple protrusions 1222 are arranged at intervals along the second direction, which is beneficial to dividing the first metal part 121 into multiple regions along the second direction, and one region can correspond to one protrusion 1222. The electrons in each region can be transmitted to the electrode lead-out portion 2011 through the corresponding protrusion 1222, thereby realizing the regional transmission of electrons in the first metal part 121. The electron transmission path in each region to the corresponding protrusion 1222 is short, which is beneficial to reducing the transmission distance of electrons, reducing the overall resistance of the first electrode sheet 1, and improving the fast charging performance and usage reliability of the battery cell 100.

[0346] In some embodiments, two adjacent first insulating portions 4121 are disconnected.

[0347] By adopting the technical solution of this embodiment, two adjacent first insulating portions 4121 are spaced apart from each other, which can save space and is beneficial for improving the energy density of the battery cell 100 .

[0348] In some implementations, see Figure 6 and Figure 12 As shown, two adjacent first insulating portions 4121 are connected.

[0349] For some examples, see Figure 6 As shown, the first insulating member 41 extends along the second direction and is of equal width. The first insulating member 41 is divided into a plurality of first insulating portions 4121 along the second direction. The plurality of first insulating portions 4121 are sequentially connected along the second direction to form an integral structure.

[0350] For some examples, see Figure 12As shown, 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, wherein the part close to the active material layer 20 is the second insulating part 4122, and the part away from the active material layer 20 can be divided into multiple first insulating parts 4121 along the second direction. The multiple first insulating parts 4121 are connected in sequence along the second direction to form an overall structure.

[0351] By adopting the technical solution of this embodiment, two adjacent first insulating parts 4121 can be directly connected to form an integral structure, which facilitates the installation of the first insulating part 4121; at the same time, the first insulating part 4121 can also cover the two opposite side surfaces of the first connecting sub-part 311 along the second direction, blocking the tip protrusions of the two opposite side surfaces of the first connecting sub-part 311 along the second direction, thereby increasing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0352] In some embodiments, please refer to Figures 12-16 As shown, the second metal part 122 includes a transition part 1221 and at least one protrusion 1222, and the transition part 1221 is connected between the protrusion 1222 and the first metal part 121; along the second direction, the size of the transition part 1221 is greater than the sum of the sizes of all the protrusions 1222, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0353] Along the first direction, the second metal portion 122 is divided into two parts: the portion close to the first metal portion 121 is the transition portion 1221, and the portion away from the first metal portion 121 is the first metal portion 121. The protrusion 1222 protrudes from the edge of the transition portion 1221 away from the first metal portion 121, away from the first metal portion 121. The first metal portion 121 is covered with the active material layer 20, while neither the transition portion 1221 nor the protrusion 1222 is covered with the active material layer 20. Along the second direction, the size of the transition portion 1221 is larger than the sum of the sizes of all the protrusions 1222, so that the size of the transition portion 1221 can approach the size of the first metal portion 121.

[0354] In some examples, the protrusion 1222 extends outward along the first direction from the side of the transition portion 1221 away from the first metal portion 121; the number of the protrusion 1222 is one, the protrusion 1222 and the transition portion 1221 form a step structure, and along the second direction, the size of the transition portion 1221 is L2, L2>l1; the number of the protrusion 1222 is multiple, the multiple protrusions 1222 protrude from the edge on the same side of the transition portion 1221, the multiple protrusions 1222 are spaced apart along the second direction, the structures of the multiple protrusions 1222 are the same, and L2>N*l1.

[0355] By adopting the technical solution of this embodiment, the transition portion 1221 has a large size along the second direction, so that the transition portion 1221 can have a larger area to connect with the first connecting portion 31, so that the electrons of the first metal portion 121 and the active material layer 20 can flow directly to the first connecting portion 31 through the transition portion 1221, which can reduce the overflow pressure between the protrusion 1222 and the transition portion 1221, reduce the heat at the connection between the protrusion 1222 and the transition portion 1221, and improve the fast charging performance of the battery cell 100.

[0356] In some embodiments, please refer to Figures 12-16 As shown, along the second direction, the size of the first metal portion 121 is L1, the size of the transition portion 1221 is L2, and 0.8≤L2 / L1≤1.

[0357] 0.8≤L2 / L1≤1, along the second direction, the size of the transition portion 1221 is less than or equal to the size of the first metal portion 121, and the size of the transition portion 1221 is greater than or equal to 0.8 times the size of the first metal portion 121, so that the size of the transition portion 1221 is not much different from or equal to the size of the first metal portion 121, wherein, the larger the size of the transition portion 1221, the larger the connection area between the transition portion 1221 and the first connecting portion 31 can be set, and the better the flow capacity between the transition portion 1221 and the first connecting portion 31.

[0358] 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.

[0359] In some examples, 0.8≤L2 / L1<1, and along the second direction, the transition portion 1221 may be located in the middle of the first metal portion 121 , and both ends of the transition portion 1221 are not flush with the first metal portion 121 .

[0360] In some examples, 0.8≤L2 / L1<1, and along the second direction, the transition portion 1221 may be arranged with one end of the first metal portion 121 or may be biased toward the first metal portion 121, so that one end of the transition portion 1221 is flush with the first metal portion 121 and the other end is not flush, or both ends are not flush.

[0361] In some examples, L2=L1, in the second direction, the size of the transition portion 1221 is equal to the size of the first metal portion 121, and in the second direction, both ends of the transition portion 1221 are flush with the first metal portion 121, and the transition portion 1221 and the first metal portion 121 are equal length structures.

[0362] By adopting the technical solution of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition portion 1221 large along the second direction, which is beneficial to increasing the connection area between the first connection portion 31 and the transition portion 1221, improving the flow capacity at the connection between the first connection portion 31 and the transition portion 1221, 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.

[0363] In some embodiments, please refer to Figures 12-16 As shown, the first weld mark 51 includes a second weld mark portion 512 , the first connecting portion 31 includes a second connecting sub-portion 312 connected to the second connecting portion 32 , and the second connecting sub-portion 312 is welded to the transition portion 1221 to form the second weld mark portion 512 .

[0364] The second connecting sub-portion 312 may refer to the portion where the first connecting portion 31 is connected to the transition portion 1221 ; a weld mark formed by welding the second connecting sub-portion 312 to the surface of the transition portion 1221 facing away from the insulating base 11 is a second weld mark portion 512 .

[0365] In some examples, the first connecting portion 31 includes a first connecting sub-portion 311 and a second connecting sub-portion 312. The first connecting sub-portion 311 is connected to the second connecting sub-portion 312 and the second connecting portion 32. The interface between the first connecting sub-portion 311 and the second connecting sub-portion 312 can refer to the end surface of the transition portion 1221 leading to the protrusion 1222 (see Figure 18 The dashed line N in the figure).

[0366] In some examples, the first connecting sub-portion 311 is welded to the protruding portion 1222 to form a first weld print portion 511, and the second connecting sub-portion 312 is welded to the transition portion 1221 to form a second weld print portion 512. The first weld print portion 511 and the second weld print portion 512 together form a first weld print 51, and the first weld print portion 511 is located between the second weld print portion 512 and the active material layer 20, that is, the first connecting portion 31 is welded to the transition portion 1221 and the protruding portion 1222 at the same time.

[0367] In some examples, the second connecting sub-portion 312 is welded to the transition portion 1221 to form a second weld mark portion 512 , the protruding portion 1222 is not welded to the first connecting sub-portion 311 , and the second weld mark portion 512 is the first weld mark 51 .

[0368] In the manufacturing process of some first electrode sheets 1, cutting is first performed along the second direction on the equal-width weld mark, and then cutting is performed in the direction away from the active material layer 20 until leaving the equal-width weld mark, and then cutting is continued for a distance in the direction away from the active material layer 20, and then cutting is continued for a distance in the second direction, and then cutting is continued in the direction toward the active material layer 20 until the equal-width weld mark is cut for a distance, and then cutting is continued along the second direction on the equal-width weld mark to obtain a second weld mark portion 512 and a first weld mark portion 511. After multiple cutting, multiple first weld marks 511 can be obtained; wherein, cutting is performed along the direction away from the active material layer 20 for a distance. The cutting position along the second direction is printed as a reference. Along the first direction, the portion of the first weld mark 51 located on the side of the cutting position facing the active material layer 20 is the second weld mark 512, and the portion located on the side of the cutting position facing away from the active material layer 20 is the first weld mark 511. The first weld mark 511 can be a protruding structure extending from the side of the second weld mark 512 facing away from the active material layer 20. After the cutting is completed, the metal layer 12 of the current collector 10 is cut out with a protruding portion 1222, and the portion of the metal layer 12 located between the protruding portion 1222 and the active material layer 20 forms a transition portion 1221.

[0369] By adopting the technical solution of this embodiment, the surface of the transition portion 1221 facing away from the insulating base 11 is welded to the first connecting portion 31, so that a portion of the current can directly flow into or out of the first connecting portion 31 through the transition portion 1221, reducing the overcurrent pressure between the protrusion 1222 and the transition portion 1221, which is beneficial to reducing the heat generation at the connection between the protrusion 1222 and the transition portion 1221, and improving the fast charging performance of the battery cell 100.

[0370] In some embodiments, please refer to Figures 12-16 As shown, the second connecting sub-portion 312 is not welded to the transition portion 1221 , and the protruding portion 1222 is welded to the first connecting sub-portion 311 to form a first weld mark portion 511 , which is a first weld mark 51 .

[0371] In some embodiments, along the second direction, the size of the transition portion 1221 is L2, the size of the second weld print portion 512 is L3, and 0.8≤L3 / L2≤1.

[0372] 0.8≤L3 / L2≤1. Along the second direction, the size L3 of the second weld mark 512 may be less than or equal to the size L2 of the transition portion 1221. The size L3 of the second weld mark 512 is greater than or equal to 0.8 times the size L2 of the transition portion 1221. The size L3 of the second weld mark 512 exceeds more than half of the size L2 of the transition portion 1221. The longer the size L3 of the second weld mark 512, the larger the welding area between the transition portion 1221 and the second connecting sub-portion 312, and the better the flow capacity of the connection between the transition portion 1221 and the second connecting sub-portion 312.

[0373] In some examples, 0.8≤L3 / L2<1, and along the second direction, the second weld print 512 may be located in the middle of the transition portion 1221 , and opposite edges of the second weld print 512 are not flush with opposite side surfaces of the transition portion 1221 .

[0374] In some examples, 0.8≤L3 / L2<1, and along the second direction, the second weld print portion 512 is arranged at one end that may also be biased toward the transition portion 1221, so that one edge of the second weld print portion 512 is flush with one side surface of the transition portion 1221, and the other edge of the second weld print portion 512 is not flush with the other side surface of the transition portion 1221.

[0375] In some examples, L3 = L2 , and along the second direction, the dimension L3 of the second weld print 512 is equal to the dimension L2 of the transition portion 1221 , and opposite edges of the second weld print 512 are flush with opposite side surfaces of the transition portion 1221 .

[0376] 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.

[0377] By adopting the technical solution of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the second weld portion 512 along the second direction larger, which is beneficial to increasing the connection area between the second connecting sub-portion 312 and the transition portion 1221, improving the flow capacity of the connection between the second connecting sub-portion 312 and the transition portion 1221, 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.

[0378] In some embodiments, please refer to Figures 12-16 As shown, the side of the transition portion 1221 facing away from the first metal portion 121 , the edge of the second weld print 512 away from the active material layer 20 , and the side of the second connecting sub-portion 312 facing away from the active material layer 20 are flush.

[0379] Along the thickness direction of the current collector 10 , the transition portion 1221 faces away from the side of the first metal portion 121 , and the edge of the second welded portion 512 away from the active material layer 20 overlaps with the side of the second connector 312 facing away from the active material layer 20 .

[0380] During the production process of the first electrode 1, after cutting the equal-width weld prints along the second direction, the side of the transition portion 1221 facing away from the first metal portion 121, the edge of the second weld print portion 512 away from the active material layer 20 and the side of the second connecting sub-portion 312 facing away from the active material layer 20 are flush.

[0381] By adopting the technical solution of this embodiment, the second weld portion 512, the second connecting sub-portion 312 and the transition portion 1221 have a regular structure and are easy to process and manufacture. In addition, the redundancy of the second connecting sub-portion 312 and the transition portion 1221 can be reduced, space can be saved, and the energy density of the battery cell 100 can be improved.

[0382] In some embodiments, please refer to Figures 12-16 As shown, the first insulating member 41 includes a second insulating portion 4122 , and the second insulating portion 4122 covers at least a portion of the second weld print portion 512 .

[0383] The second insulating portion 4122 may refer to the portion of the first insulating member 41 covering the second weld print 512. The second insulating portion 4122 may cover a portion of the second weld print 512, or may cover the entire second weld print 512.

[0384] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block the burrs on the second weld print portion 512 , reducing the short circuit risk of the battery cell 100 , and helping to improve the reliability of the battery cell 100 .

[0385] In some embodiments, along the direction from the first metal portion 121 to the second metal portion 122 , the second insulating portion 4122 protrudes from the edge of the second weld print 512 away from the active material layer 20 .

[0386] Along the thickness direction of the current collector 10 , the projection of the edge of the second weld print 512 away from the active material layer 20 is located within the projection of the second insulating portion 4122 .

[0387] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block the burrs at the edge of the second weld mark 512 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.

[0388] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the second metal portion 122 to the first metal portion 121 , the second insulating portion 4122 protrudes from the edge of the second weld print 512 close to the active material layer 20 .

[0389] Along the thickness direction of the current collector 10 , the projection of the edge of the second weld print 512 close to the active material layer 20 is located within the projection of the second insulating portion 4122 .

[0390] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block the burrs at the edge of the second weld mark 512 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.

[0391] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal part 121 to the second metal part 122, the second insulating part 4122 protrudes from the edge of the second weld print 512 away from the active material layer 20; along the direction from the second metal part 122 to the first metal part 121, the second insulating part 4122 protrudes from the edge of the second weld print 512 close to the active material layer 20.

[0392] In some examples, along the thickness direction of the current collector 10 , the projection of the second weld print 512 is located within the projection of the second insulating portion 4122 , and the second weld print 512 may be completely covered.

[0393] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block the burrs at the two opposite edges of the second weld portion 512 along the first direction, reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0394] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal portion 121 to the second metal portion 122 , the second insulating portion 4122 protrudes from a side of the second connecting sub-portion 312 away from the active material layer 20 .

[0395] Along the thickness direction of the current collector 10 , the projection of the side surface of the second connector 312 away from the active material layer 20 is located within the projection of the second insulating portion 4122 .

[0396] In some battery cells 100, burrs may be generated on the side of the second connecting sub-portion 312 facing away from the active material layer 20 during the manufacturing process, thereby causing a short circuit in the battery cell 100; in addition, during the manufacturing and use of the battery cell 100, the side of the second connecting sub-portion 312 facing away from the active material layer 20 is easily impacted and generates metal debris, and the metal debris may fall between the first pole piece 1 and the second pole piece 2, thereby causing a short circuit in the battery cell 100; in particular, the edge of the second weld stamp 512 facing away from the active material layer 20 is obtained by cutting, so that the side of the transition portion 1221 facing away from the first metal portion 121, the edge of the second weld stamp 512 away from the active material layer 20 and the side of the second connecting sub-portion 312 facing away from the active material layer 20 are flush, and large burrs may be generated on the side of the second connecting sub-portion 312 facing away from the active material layer 20, resulting in a short circuit risk in the battery cell 100.

[0397] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block burrs, metal debris and other components on the side of the second connecting sub-portion 312 facing away from the active material layer 20, reducing the risk of short circuit in the battery cell 100 and helping to improve the reliability of the battery cell 100.

[0398] In some embodiments, along the second direction, opposite side surfaces of the transition portion 1221 are flush with opposite side surfaces of the second connecting sub-portion 312 , and opposite edges of the second weld print portion 512 are flush with opposite side surfaces of the second connecting sub-portion 312 .

[0399] Along the thickness direction of the current collector 10, the projections of two opposing side surfaces of the transition portion 1221 along the second direction coincide with the projections of two opposing side surfaces of the second connecting sub-portion 312 along the second direction. The projections of two opposing edges of the second welded portion 512 along the second direction coincide with the projections of two opposing side surfaces of the second connecting sub-portion 312 along the second direction. Along the second direction, the second welded portion 512 extends from one side edge of the second connecting sub-portion 312 to the other side edge of the second connecting sub-portion 312.

[0400] In 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. In this process, along the second direction, the opposite side surfaces of the transition portion 1221 and the opposite side surfaces of the second connecting sub-portion 312 are cut so that along the second direction, the opposite side surfaces of the transition portion 1221 are respectively flush with the opposite side surfaces of the second connecting sub-portion 312, and the weld mark continuously arranged along the second direction is also cut into a plurality of second weld marks 512, so that in the first pole piece 1 obtained by cutting, along the second direction, the opposite edges of the second weld mark 512 are respectively flush with the opposite side surfaces of the second connecting sub-portion 312.

[0401] By adopting the technical solution of this embodiment, the edge structure of the first pole piece 1 relatively distributed along the second direction is regular, which can facilitate the processing and production of the first pole piece 1, and can also reduce the redundancy of the second connecting sub-portion 312 and the transition portion 1221, save space, and improve the energy density of the battery cell 100; in addition, along the second direction, the size of the second weld mark 52 portion 512 is equal to the size of the transition portion 1221, and the first weld mark 51 portion extends from one side of the transition portion 1221 along the second direction to the other side. The welding area between the transition portion 1221 and the first connecting sub-portion 311 is large, 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.

[0402] In some embodiments, please refer to Figures 12-16 As shown, along the second direction, at least one of the two opposite sides of the second insulating portion 4122 protrudes from the corresponding side surface of the second connecting sub-portion 312 .

[0403] Among the two side portions of the second insulating portion 4122 that are opposite to each other along the second direction, one side portion protrudes from the side surface of the second connecting sub-portion 312 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 second connecting sub-portion 312.

[0404] 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 second connecting sub-portion 312 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 second connecting sub-portion 312 along the second direction, thereby increasing the risk of a short circuit in the battery cell 100.

[0405] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block the burrs on the side of the second connecting sub-portion 312 along the second direction, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0406] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal portion 121 to the second metal portion 122 , the second insulating portion 4122 protrudes from the side of the second connecting sub-portion 312 facing away from the active material layer 20 .

[0407] Along the thickness direction of the current collector 10 , the projection of the side surface of the second connector 312 facing away from the active material layer 20 falls within the projection of the second insulating portion 4122 .

[0408] In some examples, the protrusion 1222 is covered with the first connecting sub-portion 311, and the first connecting sub-portion 311 is connected between the second connecting sub-portion 32 and the second connecting sub-portion 312. The side of the first connecting sub-portion 311 facing 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 interface between the first connecting sub-portion 311 and the second connecting sub-portion 312 may refer to the side of the transition portion 1221 facing away from the first metal portion 121, that is, the side of the transition portion 1221 leading out of the protrusion 1222.

[0409] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block the burrs on the side of the second connecting sub-portion 312 facing away from the active material layer 20 , thereby reducing the short circuit risk of the battery cell 100 .

[0410] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the second metal portion 122 to the first metal portion 121 , the second insulating portion 4122 protrudes from the side of the second connecting sub-portion 312 facing the active material layer 20 .

[0411] Along the thickness direction of the current collector 10 , the projection of the side surface of the second connector 312 facing the active material layer 20 falls within the projection of the second insulating portion 4122 .

[0412] By adopting the technical solution of this embodiment, the second insulating portion 4122 can block burrs on the side of the second connecting sub-portion 312 facing the active material layer 20 , thereby reducing the short circuit risk of the battery cell 100 .

[0413] In some embodiments, along the direction from the first metal portion 121 to the second metal portion 122, the second insulating portion 4122 protrudes from the side of the second connecting sub-portion 312 facing away from the active material layer 20; along the direction from the second metal portion 122 to the first metal portion 121, the second insulating portion 4122 protrudes from the side of the second connecting sub-portion 312 facing the active material layer 20.

[0414] Along the thickness direction of the current collector 10 , the projection of the second connector 312 falls within the projection of the second insulating portion 4122 , which may cover the entire second connector 312 or the second weld print 512 on the second connector 312 .

[0415] By adopting the technical solution of this embodiment, the second insulating portion 4122 can achieve overall insulation of the second connecting sub-portion 312 , which is beneficial to reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100 .

[0416] In some embodiments, please refer to Figures 12-16 As shown, the first connecting portion 31 includes at least one first connecting sub-portion 311, the first connecting sub-portion 311 is connected between the second connecting portion 32 and the second connecting sub-portion 312, the first connecting sub-portion 311 covers the surface of the protrusion 1222 facing away from the insulating base 11, and the first connecting sub-portion 311 corresponds one-to-one with the protrusion 1222; the first insulating part 41 includes at least one first insulating portion 4121, the first insulating portion 4121 is connected to the second insulating portion 4122, the first insulating portion 4121 covers the surface of the first connecting sub-portion 311 facing away from the protrusion 1222, and the first insulating portion 4121 corresponds one-to-one with the first connecting sub-portion 311.

[0417] In some examples, the second connecting sub-portion 312 is a protruding structure on the side facing away from the active material layer 20, and the side of the second connecting sub-portion 312 facing away from the active material layer 20 extends outward along the first direction to form the first connecting sub-portion 311; the first sub-portion 1211 is covered with the first insulating portion 4121, and the second insulating portion 4122 is connected to the first insulating portion 4121. The interface between the first insulating portion 4121 and the second insulating portion 4122 can refer to the interface between the second connecting sub-portion 312 and the first connecting sub-portion 311 (can refer to Figure 18 The dashed line N in the figure).

[0418] By adopting the technical solution of this embodiment, the first insulating part 4121 covers the first connecting sub-part 311, the second insulating part 4122 covers the second connecting sub-part 312, the first insulating part 4121 covers the first connecting sub-part 311 and the second connecting sub-part 312, the coverage area of ​​the first insulating part 41 is large, and the insulating effect of the first insulating part 41 is good, which reduces the short circuit risk of the battery cell 100 and improves the reliability of the battery cell 100.

[0419] In some embodiments, there are multiple protrusions 1222, and the multiple protrusions 1222 are spaced apart along the second direction; there are multiple first connecting sub-portions 311, and the multiple first connecting sub-portions 311 are spaced apart along the second direction; there are multiple second connecting portions 32, and the multiple second connecting portions 32 are spaced apart along the second direction; the first connecting sub-portions 311 are connected to the second connecting portions 32 in a one-to-one correspondence, and the multiple first connecting sub-portions 311 are connected to the side of the second connecting sub-portions 312 facing away from the active material layer 20; the second connecting sub-portions 312 are continuously arranged along the second direction.

[0420] By adopting the technical solution of this embodiment, the second connecting sub-portion 312 is continuously arranged along the second direction, and multiple first connecting sub-portions 311 can be connected into a whole. The second connecting sub-portion 312 can provide good support for the first connecting sub-portion 311, reduce the risk of the first connecting sub-portion 311 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; in addition, along the second direction, the size of the second connecting sub-portion 312 is large, which is conducive to increasing the welding area between the second connecting sub-portion 312 and the transition portion 1221, and is conducive to improving the flow capacity at the connection between the first connecting portion 31 and the transition portion 1221, improving the flow capacity of the first pole piece 1, and improving the fast charging performance and reliability of the battery cell 100.

[0421] In some embodiments, please refer to Figure 5 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 second metal portion 122 has a first end face 2101, and the pole ear portion 220 extends outward from the first end face 2101; along the direction from the first metal portion 121 toward the second metal portion 122, the second connecting sub-portion 312 is away from the side of the active material layer 20 and does not protrude from the first end face 2101.

[0422] 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 close to the second metal part 122. 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 polarities to realize the charging and discharging of the battery cell 100.

[0423] 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 second metal portion 122 forms a first end surface 2101 .

[0424] Along the thickness direction of the current collector 10, the projection of the side of the second connecting sub-portion 312 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 first connecting sub-portion 311 does not extend.

[0425] 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.

[0426] In some embodiments, please refer to Figure 5 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 second connecting sub-portion 312 .

[0427] Along the direction from the first metal part 121 to the second metal part 122, the second connecting sub-part 312 protrudes from the first end face 2101 away from the side of the active material layer 20, so that the side of the second connecting sub-part 312 facing 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 beneficial to improving the reliability of the battery cell 100.

[0428] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating member 41 protrudes from the edge of the first weld mark 51 away from the active material layer 20 .

[0429] Along the thickness direction of the current collector 10 , the projection of the edge of the first weld mark 51 away from the active material layer 20 is located within the projection range of the first insulating member 41 . The first insulating member 41 can cover the edge of the first weld mark 51 away from the active material layer 20 .

[0430] In some examples, the first weld mark 51 includes a first weld mark portion 511 , and the edge of the first weld mark 51 away from the active material layer 20 may refer to the edge of the first weld mark portion 511 away from the active material layer 20 .

[0431] In some examples, the first weld mark 51 includes a second weld mark portion 512 , and the edge of the first weld mark 51 away from the active material layer 20 may refer to the edge of the second weld mark portion 512 away from the active material layer 20 .

[0432] In some examples, the first weld print 511 includes a first weld print portion 511 and a second weld print portion 512 , and the edge of the first weld print 511 away from the active material layer 20 may refer to the edge of the first weld print 511 away from the active material layer 20 .

[0433] In some examples, the first weld print 511 includes a first weld print 511 and a second weld print 512 , and the edge of the first weld print 511 away from the active material layer 20 may refer to the edge of the second weld print 512 away from the active material layer 20 .

[0434] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the edge of the first weld mark 51 away from the active material layer 20, blocking the burrs at the edge of the first weld mark 51 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.

[0435] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating member 41 protrudes from the edge of the first weld mark 51 close to the active material layer 20 .

[0436] Along the thickness direction of the current collector 10 , the projection of the edge of the first weld mark 51 close to the active material layer 20 is located within the projection range of the first insulating member 41 , and the first insulating member 41 may cover the edge of the first weld mark 51 close to the active material layer 20 .

[0437] In some examples, the first weld mark 51 includes a first weld mark portion 511 , and the edge of the first weld mark 51 close to the active material layer 20 may refer to the edge of the first weld mark portion 511 close to the active material layer 20 .

[0438] In some examples, the first weld mark 51 includes a second weld mark portion 512 , and the edge of the first weld mark 51 close to the active material layer 20 may refer to the edge of the second weld mark portion 512 close to the active material layer 20 .

[0439] In some examples, the first weld print 511 includes a first weld print 511 and a second weld print 512 . The edge of the first weld print 511 away from the active material layer 20 may refer to the edge of the second weld print 512 close to the active material layer 20 .

[0440] In some examples, the first weld print 511 includes a first weld print portion 511 and a second weld print portion 512 , and the edge of the first weld print 511 away from the active material layer 20 may refer to the edge of the first weld print 511 close to the active material layer 20 .

[0441] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the edge of the first weld mark 51 close to the active material layer 20, thereby blocking the burrs at the edge of the first weld mark 51 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.

[0442] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal part 121 to the second metal part 122, the first insulating member 41 protrudes from the edge of the first weld mark 51 away from the active material layer 20; along the direction from the second metal part 122 to the first metal part 121, the first insulating member 41 protrudes from the edge of the first weld mark 51 close to the active material layer 20.

[0443] In some examples, along the thickness direction of the current collector 10 , the projection of the first weld mark 51 is located within the projection range of the first insulating member 41 , and the first insulating member 41 may cover the entire first weld mark 51 .

[0444] By adopting the technical solution of this embodiment, the coverage area of ​​the first insulating member 41 is increased, the short circuit risk of the battery cell 100 is reduced, and the reliability of the battery cell 100 is improved.

[0445] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating member 41 protrudes from a side of the first connecting portion 31 away from the active material layer 20 .

[0446] Along the thickness direction of the current collector 10 , the projection of the side of the first connecting portion 31 away from the active material layer 20 falls within the projection range of the first insulating member 41 , and the first insulating member 41 may cover the second connecting portion 32 .

[0447] In some examples, the first connecting portion 31 includes only the first connecting sub-portion 311 , and the side of the first connecting portion 31 away from the active material layer 20 may refer to the side of the first connecting sub-portion 311 away from the active material layer 20 .

[0448] In some examples, the first connecting portion 31 includes only the second connecting sub-portion 312 , and the side of the first connecting portion 31 away from the active material layer 20 may refer to the side of the second connecting sub-portion 312 away from the active material layer 20 .

[0449] In some examples, the first connecting portion 31 includes a first connecting sub-portion 311 and a second connecting sub-portion 312, the first connecting sub-portion 311 is connected between the second connecting sub-portion 312, and the side of the first connecting portion 31 away from the active material layer 20 may refer to the side of the first connecting sub-portion 311 away from the active material layer 20.

[0450] In some examples, the first connecting portion 31 includes a first connecting sub-portion 311 and a second connecting sub-portion 312, the first connecting sub-portion 311 is connected between the second connecting sub-portions 312, and the side of the first connecting portion 31 away from the active material layer 20 may refer to the side of the second connecting sub-portion 312 away from the active material layer 20.

[0451] By adopting the technical solution of this embodiment, the first insulating member 41 can extend from the first weld mark 51 to the second connecting portion 32, 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.

[0452] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the second metal portion 122 to the first metal portion 121 , the first insulating member 41 protrudes from a side of the first connecting portion 31 close to the active material layer 20 .

[0453] Along the thickness direction of the current collector 10, the projection of the side of the first connecting part 31 close to the active material layer 20 falls within the projection range of the first insulating part 41. The first insulating part 41 can cover the part of the metal layer 12 located between the first connecting part 31 and the active material layer 20, and can even cover the active material layer 20.

[0454] In some examples, the first connecting portion 31 includes only the first connecting sub-portion 311 , and the side of the first connecting portion 31 close to the active material layer 20 may refer to the side of the first connecting sub-portion 311 close to the active material layer 20 .

[0455] In some examples, the first connecting portion 31 includes only the second connecting sub-portion 312 , and the side of the first connecting portion 31 close to the active material layer 20 may refer to the side of the second connecting sub-portion 312 close to the active material layer 20 .

[0456] In some examples, the first connecting portion 31 includes a first connecting sub-portion 311 and a second connecting sub-portion 312, the first connecting sub-portion 311 is connected between the second connecting sub-portions 312, and the side of the first connecting portion 31 close to the active material layer 20 may refer to the side of the second connecting sub-portion 312 close to the active material layer 20.

[0457] In some examples, the first connecting portion 31 includes a first connecting sub-portion 311 and a second connecting sub-portion 312, the first connecting sub-portion 311 is connected between the second connecting sub-portions 312, and the side of the first connecting portion 31 close to the active material layer 20 may refer to the side of the first connecting sub-portion 311 close to the active material layer 20.

[0458] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the side of the first connecting portion 31 close to the active material layer 20, thereby blocking burrs on the side, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0459] In some embodiments, please refer to Figures 12-16 As shown, along the direction from the first metal part 121 to the second metal part 122, the first insulating part 41 protrudes from the side of the first connecting part 31 away from the active material layer 20, and along the direction from the second metal part 122 to the first metal part 121, the first insulating part 41 protrudes from the side of the first connecting part 31 close to the active material layer 20.

[0460] In some examples, along the thickness direction of the current collector 10 , the projection of the first connection portion 31 is located within the projection range of the first insulating member 41 . The first insulating member 41 may cover the entire first connection portion 31 or completely cover the first weld mark 51 on the first connection portion 31 .

[0461] By adopting the technical solution of this embodiment, the first insulating member 41 can cover the entire first connecting portion 31, thereby increasing the coverage area 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.

[0462] In some embodiments, please refer to Figure 7 As shown, along the first direction, the first weld mark 51 is spaced apart from the active material layer 20 .

[0463] 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 .

[0464] 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 part 31 and the active material layer 20 to reduce the risk of lithium plating caused by the contact between the first connecting part 31 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 part 31 close to the active material layer 20, so that the first weld mark 51 will not extend to the side of the first connecting part 31 close to the active material layer 20, reducing the risk of the first connecting part 31 being welded through or cracked at the side close to 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.

[0465] 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 portion 31 close to the active material layer 20, so that the first weld mark 51 will not extend to the side of the first connecting portion 31 close to the active material layer 20, reducing the risk of the first connecting portion 31 being welded through or cracked at the side close to 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 portion 31 can be connected to the active material layer 20, or can be set at intervals.

[0466] 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 connecting portion 31 and the metal layer 12 will not be welded to the active material layer 20, reducing the risk of poor welding between the first connecting portion 31 and the metal layer 12, and improving the reliability of the battery cell 100.

[0467] In some embodiments, please refer to Figure 7 As shown, the electrode assembly 101 further includes a second insulating member 42 . The second insulating member 42 covers the surface of the second metal portion 122 facing away from the insulating substrate 11 . The second insulating member 42 is located between the first weld mark 51 and the active material layer 20 .

[0468] 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.

[0469] 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 .

[0470] In some examples, a portion of the second insulating member 42 may be located between the first connecting portion 31 and the metal layer 12, and another portion of the second insulating member 42 may be located between the first connecting portion 31 and the active material layer 20; or, the entire second insulating member 42 may be located between the first connecting portion 31 and the active material layer 20.

[0471] 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.

[0472] In some embodiments, please refer to Figure 7 As shown, along the first direction, the first connection portion 31 is spaced apart from the active material layer 20 .

[0473] Along the thickness direction of the current collector 10 , the projection of the first connecting portion 31 does not overlap with the projection of the active material layer 20 .

[0474] By adopting the technical solution of this embodiment, the first connecting portion 31 does not contact 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 .

[0475] In some embodiments, please refer to Figure 7 As shown, at least a portion of the second insulating member 42 is located between the first connecting portion 31 and the active material layer 20 .

[0476] A portion of the second insulating member 42 is located between the first connecting portion 31 and the active material layer 20 , or the entire second insulating member 42 is located between the first connecting portion 31 and the active material layer 20 .

[0477] In some examples, the first connecting portion 31 only includes the first connecting sub-portion 311. Along the first direction, the first connecting sub-portion 311 is spaced apart from the transition portion 1221. The second insulating member 42 may cover the portion of the protrusion 1222 close to the transition portion 1221, or may cover the transition portion 1221, or may cover the portion of the protrusion 1222 close to the transition portion 1221 and the transition portion 1221 at the same time.

[0478] In some examples, the first connection portion 31 includes a first connection sub-portion 311 and a second connection sub-portion 312 , and the second insulating member 42 covers the transition portion 1221 and is located between the second connection sub-portion 312 and the active material layer 20 .

[0479] 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 second metal portion 122 will be bent accordingly, so that the portion of the second metal portion 122 located between the first connecting portion 31 and the active material layer 20 may have problems such as cracks. The second insulating member 42 covers the portion of the second metal portion 122 located between the first connecting portion 31 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 second metal portion 122 located between the first connecting portion 31 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.

[0480] In some embodiments, please refer to Figure 5 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 second metal portion 122 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.

[0481] 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.

[0482] In some embodiments, please refer to Figure 7 As shown, along the first direction, 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 at least a portion of the second insulating member 42 .

[0483] 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 .

[0484] The first insulating member 41 may cover a portion of the second insulating member 42 , or may cover the entire second insulating member 42 .

[0485] 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.

[0486] 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.

[0487] In some embodiments, please refer to Figure 7 As shown, the second insulating member 42 includes a first phase-change heat storage layer, and the first phase-change heat storage layer covers the surface of the second metal portion 122 facing away from the insulating base 11 .

[0488] The second insulating member 42 includes a first phase-change heat storage layer or other layer structure, wherein the second insulating member 42 can adopt a multi-layer structure. For example, the second insulating member 42 includes a second insulating base layer and a second adhesive layer, the first phase-change heat storage layer is connected between the second insulating base layer and the second adhesive layer, and the second adhesive layer is bonded between the second metal part 122 and the first phase-change heat storage layer; the second insulating base layer and the second adhesive layer can be used to support the first phase-change heat storage layer to maintain the stable structural form of the second insulating member 42 and reduce the risk of the second insulating member 42 falling off.

[0489] The second insulating member 42 only includes the first phase-change heat storage layer, that is, the second insulating member 42 is the first phase-change heat storage layer.

[0490] The first phase change heat storage layer may refer to a layer structure made of a phase change heat storage material; a phase change heat storage material is a type of material that can store and release a large amount of heat energy through phase transition (such as from solid to liquid or from liquid to gas) within a specific temperature range. The latent heat absorbed or released by such a material during the phase change process is much greater than the heat that can be stored through heat conduction or convection within the same temperature range. Among them, the phase change heat storage material may have the stable property of not reacting with or dissolving the electrolyte, so that the second phase change heat storage layer 4113 can stably function in the battery cell 100. The phase change heat storage material may be, but is not limited to, fatty acids, paraffin, nitrates, carbonates, and the like.

[0491] During the charge and discharge process of the battery cell 100 , the second metal portion 122 is prone to heat up. The temperature of the second metal portion 122 rises, which may increase the risk of cracks or breakage in the second metal portion 122 and affect the electron transmission capability of the second metal portion 122 .

[0492] By adopting the technical solution of this embodiment, during the charging and discharging process of the battery cell 100, the first phase change heat storage layer can absorb the heat of the second metal part 122, reduce the temperature of the second metal part 122, and reduce the risk of cracks and breakage of the second metal part 122, which is beneficial to improving the electron transmission capacity of the second metal part 122 and improving the fast charging performance and usage reliability of the battery cell 100.

[0493] In some embodiments, the first phase-change heat storage layer includes an organic heat storage material layer or an inorganic heat storage material layer.

[0494] The organic heat storage material layer may refer to a layer structure made of an organic heat storage material. It is understandable that the organic heat storage material layer may be made of only the organic heat storage material, or may be made by mixing the organic heat storage material with other materials.

[0495] The inorganic heat storage material layer may refer to a layer structure made of inorganic heat storage material. It can be understood that the inorganic heat storage material layer may be made of only inorganic heat storage material, or may be made by mixing inorganic heat storage material with other materials.

[0496] In some examples, the first phase change heat storage layer includes an organic heat storage material layer. The first phase change heat storage layer is made of organic heat storage material. The organic heat storage material has good cycle stability and thermal stability, which is conducive to maintaining the stable structural form of the second insulating member 42, improving the stability of the second insulating member 42 fixed on the second metal part 122, reducing the risk of the second insulating member 42 falling off, and improving the reliability of the battery cell 100.

[0497] In some examples, the first phase change heat storage layer includes an inorganic heat storage material layer. The first phase change heat storage layer is made of inorganic heat storage material. The inorganic heat storage material has a strong heat storage capacity, which is beneficial to reducing the temperature of the second metal part 122 and improving the reliability of the battery cell 100. In addition, the cost of the inorganic heat storage material is low, which is beneficial to reducing the production cost of the battery cell 100.

[0498] In some examples, the first phase-change heat storage layer includes an organic heat storage material layer and an inorganic heat storage material layer.

[0499] By adopting the technical solution of this embodiment, the first phase-change heat storage layer can have the performance of both the organic heat storage material layer and the inorganic heat storage material layer, which is beneficial to improving the performance and reliability of the battery cell 100.

[0500] In some embodiments, the first phase-change heat storage layer includes an organic heat storage material layer, and the organic heat storage material layer includes a fatty acid layer, a paraffin layer, a linear alkane layer, a fatty alcohol layer, or an ester material layer.

[0501] The fatty acid layer may refer to a layer structure made of fatty acids. It is understandable that the fatty acid layer may be made of fatty acids alone or may be made by mixing fatty acids with other materials.

[0502] The paraffin layer may refer to a layer structure made of paraffin. It is understandable that the paraffin layer may be made of paraffin only or may be made of a mixture of paraffin and other materials.

[0503] The linear alkane layer may refer to a layer structure made of linear alkanes. It is understandable that the linear alkane layer may be made of linear alkanes alone or may be made by mixing linear alkanes with other materials.

[0504] The fatty alcohol layer may refer to a layer structure made of fatty alcohol. It is understandable that the fatty alcohol layer may be made of fatty alcohol alone or a mixture of fatty alcohol and other materials.

[0505] The ester material layer may refer to a layer structure made of ester material. It is understandable that the ester material layer may be made of ester material alone, or may be made by mixing ester material with other materials.

[0506] The organic heat storage material layer may include one or more of a fatty acid layer, a paraffin layer, a linear alkane layer, a fatty alcohol layer, and an ester material layer; for example, some of these layers can maintain a stable structural morphology below 200°C.

[0507] By adopting the technical solution of this embodiment, the organic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell 100, the first phase change heat storage layer can better absorb the heat of the second metal part 122, reduce the temperature of the second metal part 122, and improve the reliability of the battery cell 100; in addition, the first phase change heat storage layer can also maintain a stable structural form, reduce the risk of the second insulating member 42 falling off, and is conducive to improving the reliability of the battery cell 100.

[0508] In some embodiments, the first phase change heat storage layer includes an inorganic heat storage material layer, and the inorganic heat storage material layer includes a nitrate layer, a carbonate layer, a fluoride salt layer, or a hydrochloride layer.

[0509] The nitrate layer may refer to a layer structure made of nitrate. It is understandable that the nitrate layer may be made of nitrate alone or may be made by mixing nitrate with other materials.

[0510] The carbonate layer may refer to a layer structure made of carbonate. It is understandable that the carbonate layer may be made of carbonate alone or may be made by mixing carbonate with other materials.

[0511] The fluoride salt layer may refer to a layer structure made of fluoride salt. It is understandable that the fluoride salt layer may be made of fluoride salt alone or may be made by mixing fluoride salt with other materials.

[0512] The hydrochloride layer may refer to a layer structure made of hydrochloride. It is understandable that the hydrochloride layer may be made of hydrochloride alone or may be made by mixing hydrochloride with other materials.

[0513] The inorganic heat storage material layer includes one or more of a nitrate layer, a carbonate layer, a fluoride layer and a hydrochloride layer. For example, some of these layers can maintain a stable structural morphology within a temperature range of 200°C to 900°C.

[0514] By adopting the technical solution of this embodiment, the inorganic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell 100, the first phase change heat storage layer can better absorb the heat of the second metal part 122, reduce the temperature of the second metal part 122, and improve the reliability of the battery cell 100. In addition, the first phase change heat storage layer can also maintain a stable structural form, reducing the risk of the second insulating member 42 falling off, which is conducive to improving the reliability of the battery cell 100.

[0515] In some embodiments, please refer to Figure 17 As shown, along the first direction, 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 .

[0516] It can be understood that, of the two sides of the first insulating member 41 relatively distributed along the first direction, one side covers the first weld mark 51, and the other side 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 portion 31, or can cover the entire active material layer 20.

[0517] Along the first direction, the first insulating member 41 extends from the first weld mark 51 to the active material layer 20, so that the portions of the metal layer 12 and the first connection portion 31 located between the first weld mark 51 and the active material layer 20 are covered by the first insulating member 41. The portion of the metal layer 12 located between the first weld mark 51 and the active material layer 20 may or may not be covered by the second insulating member 42.

[0518] In some examples, a portion of the metal layer 12 between the first weld mark 51 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 .

[0519] In some examples, the portion of the metal layer 12 located between the first weld mark 51 and the active material layer 20 may not be covered by the second insulating member 42. The first insulating member 41 extends from the first weld mark 51 to the active material layer 20, thereby covering the portion of the metal layer 12 located between the first connecting portion 31 and the active material layer 20, thereby achieving 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, thereby increasing 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.

[0520] By adopting the technical solution of this embodiment, the first insulating member 41 extends from the first weld mark 51 to the active material layer 20. The first insulating member 41 has a wide coverage area and a good insulation effect, which helps to improve the reliability of the battery cell 100. The first insulating member 41 can cover the end of the active material layer 20 near the second metal portion 122, thereby blocking burrs on the active material layer 20 near the second metal portion 122, reducing the risk of short circuits in the battery cell 100 and improving the reliability of the battery cell 100.

[0521] In some embodiments, please refer to Figure 7 As shown, there are two metal layers 12, which cover the opposite sides of the insulating substrate 11 along the thickness direction of the current collector 10; there are two active material layers 20, which cover the first metal parts 121 of the two metal layers 12 respectively; there are two conductive components 30, which have first connecting parts 31 welded to the second metal parts 122 of the two metal layers 12 respectively to form two first weld marks 51; there are two first insulating parts 41, which cover the two first weld marks 51 respectively.

[0522] 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 first metal parts 121 of the two metal layers 12; the first connecting part 31 of a conductive component 30 is welded to the surface of the second metal part 122 of one of the metal layers 12 facing away from the insulating base 11 and forms a first weld mark 51, and the first connecting part 31 of the other conductive component 30 is welded to the surface of the second metal part 122 of the other metal layer 12 facing away from the insulating base 11 and also forms a first weld mark 51. 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 two first weld marks 51.

[0523] 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 connecting the two metal layers 12, thereby breaking the insulation limitation of the insulating base 11, 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.

[0524] In some embodiments, please refer to Figure 18 As shown, along the direction from the first metal part 121 to the second metal part 122, the first insulating member 41 protrudes from the metal layer 12 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.

[0525] The blocking portion 4131 may refer to a portion of the first insulating member 41 that protrudes from a side of the metal layer 12 away from the active material layer 20 . The blocking portion 4131 is located on one side of the second connection portion 32 along the second direction.

[0526] 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 .

[0527] In some examples, the first connecting portion 31 only includes a first connecting sub-portion 311. Along the first direction, one side of the first insulating member 41 can cover the first metal portion 121, and the other side of the first insulating member 41 covers the first weld print 511 on the first connecting sub-portion 311. Along the direction from the first metal portion 121 to the second metal portion 122, the first insulating member 41 protrudes from the first metal portion 121 and forms a blocking portion 4131 corresponding to the area of ​​the first metal portion 121 where the protrusion 1222 is not led out. During the manufacture or use of the battery cell 100, burrs, metal debris and other components may be generated in the area of ​​the first metal portion 121 where the protrusion 1222 is not led out, thereby increasing the short circuit risk of the battery cell 100. The blocking portion 4131 can block the burrs, metal debris and other components in these areas, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0528] In some examples, the first connector 31 includes a first connector sub-portion 311 and a second connector sub-portion 312. The first insulating member 41 covers the first connector sub-portion 311 and the second connector sub-portion 312. Along the direction from the first metal portion 121 to the second metal portion 122, the first insulating member 41 protrudes from the second connector sub-portion 312 and forms a blocking portion 4131 corresponding to the area where the second connector sub-portion 312 is not extended from the first connector sub-portion 311. During the manufacture or use of the battery cell 100, burrs, metal debris, and other components may form in the area where the second connector sub-portion 312 is not extended from the first connector sub-portion 311, increasing the risk of short circuits in the battery cell 100. The blocking portion 4131 can block burrs, metal debris, and other components in these areas, reducing the risk of short circuits in the battery cell 100 and improving the reliability of the battery cell 100.

[0529] By adopting the technical solution of this embodiment, the blocking portion 4131 can block burrs, metal debris and other components at the edge of the metal layer 12, reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0530] In some embodiments, please refer to Figure 18 As shown, the blocking portions 4131 of the two first insulating members 41 are in contact with each other.

[0531] 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 protruding portions 1222 of the metal layer 12, 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.

[0532] By adopting the technical solution of this embodiment, after the blocking parts 4131 of the two first insulating parts 41 are bonded together, burrs, metal debris and other components on the edge of the metal layer 12 can be wrapped, thereby 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.

[0533] In some embodiments, please refer to Figure 7 As shown, the second connection portions 32 of the two conductive members 30 are welded to form a second weld mark 52 .

[0534] In some examples, along the direction from the first metal portion 121 to the second metal portion 122, the portion of the conductive member 30 protruding from the side of the protrusion 1222 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.

[0535] 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.

[0536] In some embodiments, please refer to Figure 7 As shown, the first insulating member 41 covers at least a portion of the second weld mark 52 .

[0537] 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 .

[0538] 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.

[0539] In some embodiments, along the direction from the first metal portion 121 to the second metal portion 122 , the first insulating member 41 protrudes beyond the second weld mark 52 away from the edge of the active material layer 20 .

[0540] 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 .

[0541] 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 completely cover the second weld mark 52 .

[0542] 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.

[0543] In some embodiments, please refer to Figure 5As 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 second metal portion 122 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.

[0544] In some examples, the first insulating member 41 includes a first insulating portion 4121. 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 and the first insulating portion 4121 are arranged opposite to each other. The first insulating portion 4121 can block the pointed protrusion at the first end face 2101, thereby reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0545] In some examples, the first insulating member 41 includes a second insulating portion 4122. Along the thickness direction of the current collector 10, the projection of the first end surface 2101 is located within the projection of the second insulating portion 4122. The first end surface 2101 and the second insulating portion 4122 are disposed opposite each other. The second insulating portion 4122 can block the pointed protrusion at the first end surface 2101, thereby reducing the risk of short circuits in the battery cell 100 and improving the reliability of the battery cell 100. Along the thickness direction of the current collector 10, the projection of the first end surface 2101 can be located within the projection of the second connecting sub-portion 312.

[0546] 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 first metal portion 121 to the second metal portion 122, the main functional portion 210 protrudes from the second connecting sub-portion 312 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 first metal portion 121 to the second metal portion 122, the main functional portion 210 does not protrude from the second connecting sub-portion 312 away from the side of the active material layer 20.

[0547] 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 .

[0548] In some embodiments, the first insulating member 41 has a glass transition temperature greater than or equal to 150° C.

[0549] The glass transition temperature (GTT) refers to the temperature at which a material transitions from a glassy state to a highly elastic state. When the temperature is below the GTT, the first insulating member 41 maintains a stable structure. When the temperature is above the GTT, the first insulating member 41 melts. The higher the GTT of the first insulating member 41, the better its high-temperature resistance and structural stability in high-temperature environments.

[0550] The glass transition temperature of the first insulating member 41 may be measured in accordance with the national standard GB / T 19466.1-2004.

[0551] In some examples, the glass transition temperature of the first insulating member 41 may be 150°C or any value above 150°C. For example, the glass transition temperature of the first insulating member 41 may be, but is not limited to, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 220°C, 250°C, 300°C, or 350°C.

[0552] During the charge and discharge process of some battery cells 100, heat may occur at the first weld mark 51. The temperature increase at the first weld mark 51 may cause the first insulating member 41 to melt, thereby exposing burrs, metal debris and other components on the first weld mark 51, thereby increasing the short circuit risk of the battery cell 100 and reducing the reliability of the battery cell 100.

[0553] By adopting the technical solution of this embodiment, the glass transition temperature of the first insulating member 41 is greater than or equal to 150°C, so that during the charging and discharging process of the battery cell 100, the first insulating member 41 can maintain a stable structural form, reducing the risk of melting of the first insulating member 41, reducing the risk of exposure of burrs, metal debris and other components on the first weld mark 51, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0554] In some embodiments, the glass transition temperature of the first insulating member 41 is greater than or equal to 200° C.

[0555] By adopting the technical solution of this embodiment, the glass transition temperature of the first insulating member 41 is greater than or equal to 200°C, so that during the charging and discharging process of the battery cell 100, the first insulating member 41 can better maintain a stable structural shape, the first insulating member 41 is not prone to melting, and the first insulating member 41 can stably block the burrs of the first weld mark 51, which is beneficial to reducing the short circuit risk of the battery cell 100 and improving the reliability of the battery cell 100.

[0556] In some embodiments, the specific heat capacity of the first insulating member 41 is greater than or equal to 1.2 J / g·°C.

[0557] Specific heat capacity refers to the amount of heat absorbed (or released) per unit mass of a substance when its temperature rises (or falls) by 1°C. Specific heat capacity is an important thermal property of a substance, reflecting its ability to store thermal energy. Given a constant temperature rise, the greater the specific heat capacity of a substance, the more heat it absorbs.

[0558] The larger the specific heat capacity of the first insulating member 41 is, the smaller the temperature rise of the first insulating member 41 will be after the first insulating member 41 absorbs more heat, thereby making the first insulating member 41 exhibit better heat resistance.

[0559] The specific heat capacity of the first insulating member 41 may be measured in accordance with the method described in the national standard GB / T 5990-2021.

[0560] In some examples, the specific heat capacity of the first insulating member 41 may be 1.2 J / g·°C or any value above 1.2 J / g·°C. For example, the specific heat capacity of the first insulating member 41 may be, but is not limited to, 1.2 J / g·°C, 1.5 J / g·°C, 2 J / g·°C, or 3 J / g·°C.

[0561] By adopting the technical solution of this embodiment, the specific heat capacity of the first insulating member 41 is designed to be greater than or equal to 1.2 J / g·°C. Therefore, during the charge and discharge process of the battery cell 100, the first insulating member 41 can absorb the heat at the first weld mark 51, thereby reducing the temperature of the first weld mark 51. The temperature rise of the first insulating member 41 is small, which reduces the risk of melting of the first insulating member 41. The first insulating member 41 can stably block the burrs of the first weld mark 51, reduce the short circuit risk of the battery cell 100, and improve the reliability of the battery cell 100.

[0562] In some embodiments, the glass transition temperature of the first insulating member 41 is greater than or equal to 150° C.; and the specific heat capacity of the first insulating member 41 is greater than or equal to 1.2 J / g·° C.

[0563] By adopting the technical solution of this embodiment, the specific heat capacity of the first insulating member 41 is set to be greater than or equal to 1.2 J / g·°C, so that the first insulating member 41 can absorb heat at the first weld mark 51 and generate a small temperature rise. The design of the glass transition temperature of the first insulating member 41 being greater than or equal to 150°C ensures that after the first insulating member 41 absorbs heat and heats up, the temperature of the first insulating member 41 is unlikely to exceed the glass transition temperature of the first insulating member 41, so that the first insulating member 41 can maintain reliable mechanical strength and structural integrity. Therefore, throughout the life cycle of the battery cell 100, the first insulating member 41 can effectively cover burrs, metal debris and other components of the first weld mark 51, reducing the risk of insulation failure caused by heat at the first weld mark 51, which is conducive to improving the reliability of the battery cell 100.

[0564] In some embodiments, see Figures 19-21 As shown, the first insulating member 41 includes a first insulating base layer 4111 and a first adhesive layer 4112 , and the first adhesive layer 4112 is bonded between the first weld mark 51 and the first insulating base layer 4111 .

[0565] The first insulating member 41 is constructed in the form of an adhesive tape. The first insulating base layer 4111 may refer to the main body of the first insulating member 41. The first adhesive layer 4112 may refer to the adhesive coating the surface of the first insulating base layer 4111. Materials for the first insulating base layer 4111 may include polyethylene terephthalate, polypropylene, etc. Materials for the first adhesive layer 4112 may include acrylic, rubber, and latex. The first insulating base layer 4111 and the second insulating base layer may be the same or different. The first adhesive layer 4112 and the second adhesive layer may be the same or different.

[0566] In some battery cells 100, insulating glue (for example, hot melt glue, etc.) can be applied on 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.

[0567] By adopting the technical solution of this embodiment, the first insulating member 41 adopts a tape structure, and the first insulating member 41 can be directly attached to the first weld mark 51, reducing the risk of missing coverage; the first insulating base layer 4111 and the first adhesive layer 4112 cover the first weld mark 51 to block burrs on the first weld mark 51. The thickness of the first insulating base layer 4111 and the first 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 first insulating base layer 4111 has good structural strength and can stably block burrs on the first weld mark 51, thereby improving the reliability of the battery cell 100; the first adhesive layer 4112 can stably fix the first insulating base layer 4111 to the first weld mark 51, reducing the risk of the first insulating member 4111 falling off; metal debris from the first weld mark 51 can also adhere to the first adhesive layer 4112, which can effectively reduce the risk of metal debris from the first weld mark 51 falling off and reduce the risk of short circuit in the battery cell 100.

[0568] In some embodiments, see Figures 19-21 As shown, the first insulating member 41 further includes a second phase change heat storage layer 4113 , which is connected between the first insulating base layer 4111 and the first adhesive layer 4112 , and the first adhesive layer 4112 is bonded between the second phase change heat storage layer 4113 and the first weld mark 51 .

[0569] The second phase-change heat storage layer 4113 may be a component made of a phase-change heat storage material. The phase-change heat storage material may be stable, non-reactive and insoluble in the electrolyte, enabling the second phase-change heat storage layer 4113 to function stably within the battery cell 100. Phase-change heat storage materials may include, but are not limited to, fatty acids, paraffin wax, nitrates, carbonates, and the like. The first phase-change heat storage layer and the second phase-change heat storage layer 4113 may be the same or different.

[0570] The insulating base 11, the second phase change heat storage layer 4113 and the first adhesive layer 4112 are stacked, and the second phase change heat storage layer 4113 is connected between the insulating base 11 and the first adhesive layer 4112. When the first insulating member 41 covers the first weld mark 51, the insulating base 11, the second phase change heat storage layer 4113 and the first adhesive layer 4112 are stacked along the thickness direction of the current collector 10, and the first adhesive layer 4112 is located between the first weld mark 51 and the second phase change heat storage layer 4113.

[0571] By adopting the technical solution of this embodiment, the second phase change heat storage layer 4113 can be used to absorb heat at the first weld mark 51 during the phase change process, thereby reducing the temperature rise of the first insulating base layer 4111 and the first adhesive layer 4112, and reducing the risk of melting of the first insulating base layer 4111 and the first adhesive layer 4112, which is beneficial to maintaining the structural stability of the first insulating member 41 and improving the reliability of the battery cell 100.

[0572] In some embodiments, the second phase-change heat storage layer 4113 includes an organic heat storage material layer or an inorganic heat storage material layer.

[0573] In some examples, the second phase change heat storage layer 4113 includes an organic heat storage material layer. The second phase change heat storage layer 4113 is made of an organic heat storage material. The organic heat storage material has good cycle stability and thermal stability, which is conducive to maintaining the stable structural form of the first insulating part 41, improving the stability of the first insulating part 41 fixed on the first weld mark 51, reducing the risk of the first insulating part 41 falling off, and improving the reliability of the battery cell 100.

[0574] In some examples, the second phase change heat storage layer 4113 includes an inorganic heat storage material layer. The second phase change heat storage layer 4113 is made of inorganic heat storage material. The inorganic heat storage material has a strong heat storage capacity, which is beneficial to reducing the temperature at the first weld mark 51 and improving the reliability of the battery cell 100. In addition, the cost of the inorganic heat storage material is low, which is beneficial to reducing the production cost of the battery cell 100.

[0575] In some examples, the second phase-change heat storage layer 4113 includes an organic heat storage material layer and an inorganic heat storage material layer.

[0576] By adopting the technical solution of this embodiment, the second phase-change heat storage layer 4113 can simultaneously combine the performance of the organic heat storage material layer and the inorganic heat storage material layer, which is beneficial to improving the performance and reliability of the battery cell 100.

[0577] In some embodiments, the second phase-change heat storage layer 4113 includes an organic heat storage material layer, and the organic heat storage material layer includes a fatty acid layer, a paraffin layer, a linear alkane layer, a fatty alcohol layer, or an ester material layer.

[0578] The organic heat storage material layer may include one or more of a fatty acid layer, a paraffin layer, a linear alkane layer, a fatty alcohol layer, and an ester material layer; for example, some of these layers can maintain a stable structural morphology below 200°C.

[0579] By adopting the technical solution of this embodiment, the organic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell 100, the second phase change heat storage layer 4113 can effectively absorb the heat at the first weld mark 51, reducing the temperature rise of the first insulating base layer 4111 and the first adhesive layer 4112. This is conducive to maintaining a stable structural form of the first insulating base layer 4111, and can stably block burrs, metal debris and other components on the first weld mark 51, reducing the risk of the first insulating component 41 falling off, and improving the reliability of the battery cell 100.

[0580] In some embodiments, the second phase-change heat storage layer 4113 includes an inorganic heat storage material layer, and the inorganic heat storage material layer includes a nitrate layer, a carbonate layer, a fluoride salt layer, or a hydrochloride layer.

[0581] By adopting the technical solution of this embodiment, the inorganic heat storage material layer adopts the above-mentioned structure. During the charging and discharging process of the battery cell 100, the second phase change heat storage layer 4113 can effectively absorb the heat at the first weld mark 51, reducing the temperature rise of the first insulating base layer 4111 and the first adhesive layer 4112, which is conducive to maintaining a stable structural form of the first insulating base layer 4111, and can stably block burrs, metal debris and other components on the first weld mark 51, reducing the risk of the first insulating component 41 falling off, and improving the reliability of the battery cell 100.

[0582] In some embodiments, see Figures 19-21 As shown, the thickness of the second phase change heat storage layer 4113 ranges from 1 μm to 5 μm.

[0583] The thickness of the second phase-change heat storage layer 4113 is T1, where 1 μm≤T1≤5 μm.

[0584] The value of T1 may be 1 μm, 5 μm, or any value between 1 μm and 5 μm; for example, the value of T1 may be, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm.

[0585] By adopting the technical solution of this embodiment, the design of the second phase change heat storage layer 4113 having a thickness greater than or equal to 1 μm enables the second phase change heat storage layer 4113 to absorb heat at the first weld mark 51, thereby reducing the temperature at the first weld mark 51, which is beneficial to maintaining the mechanical strength and structural stability of the first insulating member 41 and improving the reliability of the battery cell 100; the design of the second phase change heat storage layer 4113 having a thickness less than or equal to 5 μm is beneficial to reducing the space and weight occupied by the phase change heat storage and improving the energy density of the battery cell 100.

[0586] In some embodiments, the glass transition temperature of the first adhesive layer 4112 is greater than the phase change temperature of the second phase change heat storage layer 4113 , and / or the glass transition temperature of the first insulating base layer 4111 is greater than the phase change temperature of the second phase change heat storage layer 4113 .

[0587] Phase transition temperature can refer to the phase transition temperature in an endothermic process. The phase transition temperature in an endothermic process usually refers to the specific temperature that a substance needs to absorb heat to reach when it changes from one phase to another. The following are some common endothermic phase transition types and their corresponding phase transition temperatures:

[0588] Melting: When a solid melts into a liquid, it needs to absorb heat, and its phase change temperature is called the melting point.

[0589] Evaporation: When a liquid evaporates into a gas, it absorbs heat. The boiling point of a liquid can be considered an example of an endothermic phase change temperature.

[0590] Sublimation: When a solid sublimates directly into a gas, it needs to absorb heat, and its phase change temperature is called the sublimation point.

[0591] In some examples, the glass transition temperature of the first adhesive layer 4112 is greater than the phase change temperature of the second phase change heat storage layer 4113. When the second phase change heat storage layer 4113 undergoes an endothermic phase change, the first adhesive layer 4112 has a stable structural morphology, which is beneficial to maintaining the mechanical strength, structural stability and adhesion of the first insulating member 41, so that the first insulating member 41 can be stably fixed on the first weld 51, reducing the risk of insulation failure of the first insulating member 41, and helping to improve the reliability of the battery cell 100.

[0592] In some examples, the glass transition temperature of the first insulating base layer 4111 is greater than the phase change temperature of the second phase change heat storage layer 4113. When the second phase change heat storage layer 4113 undergoes an endothermic phase change, the first insulating base layer 4111 is in a stable structural form, which is beneficial to maintaining the mechanical strength and structural stability of the first insulating member 41, reducing the risk of insulation failure of the first insulating member 41, and improving the reliability of the battery cell 100.

[0593] In some examples, the glass transition temperature of the first adhesive layer 4112 is greater than the phase change temperature of the second phase change heat storage layer 4113, and the glass transition temperature of the first insulating base layer 4111 is greater than the phase change temperature of the second phase change heat storage layer 4113; when the glass transition temperature of the first insulating base layer 4111 is greater than the phase change temperature of the second phase change heat storage layer 4113, and the second phase change heat storage layer 4113 undergoes an endothermic phase change, the first insulating base layer 4111 and the first adhesive layer 4112 are in a stable structural form, which is beneficial to maintaining the mechanical strength, structural stability and adhesion of the first insulating member 41, so that the first insulating member 41 can be stably fixed to the first weld mark 51, reducing the risk of insulation failure of the first insulating member 41, and helping to improve the reliability of the battery cell 100.

[0594] By adopting the technical solution of this embodiment, it is beneficial to maintain the mechanical strength and structural stability of the first insulating member 41 , reduce the risk of insulation failure of the first insulating member 41 , and improve the reliability of the battery cell 100 .

[0595] In some embodiments, the first insulating base layer 4111 includes a polypropylene layer, a polyethylene terephthalate layer, an aramid 1313 layer, a polyvinylidene fluoride layer, or a cellulose layer.

[0596] The polypropylene layer may refer to a layer structure made of polypropylene. It is understandable that the polypropylene layer may be made of polypropylene alone or may be made by mixing polypropylene with other materials.

[0597] The polyethylene terephthalate layer may refer to a layer structure made of polyethylene terephthalate. It is understandable that the polyethylene terephthalate layer may be made of polyethylene terephthalate alone or may be made of a mixture of polyethylene terephthalate and other materials.

[0598] The aramid 1313 layer may refer to a layer structure made of aramid 1313. It is understandable that the aramid 1313 layer may be made of only aramid 1313 or may be made of a mixture of aramid 1313 and other materials.

[0599] The polyvinylidene fluoride layer may refer to a layer structure made of polyvinylidene fluoride. It is understandable that the polyvinylidene fluoride layer may be made of polyvinylidene fluoride alone or may be made of a mixture of polyvinylidene fluoride and other materials.

[0600] The cellulose layer may refer to a layer structure made of cellulose. It is understandable that the cellulose layer may be made of cellulose alone or may be made of a mixture of cellulose and other materials.

[0601] The first insulating base layer 4111 includes one or more of a polypropylene layer, a polyethylene terephthalate layer, an aramid 1313 layer, a polyvinylidene fluoride layer, and a cellulose layer.

[0602] By adopting the technical solution of this embodiment, the first insulating base layer 4111 adopts the above-mentioned structure. During the charging and discharging process of the battery cell 100, the first insulating base layer 4111 can maintain a stable structural form and is not prone to melting. The first insulating part 41 has good high temperature resistance, which is beneficial to improving the reliability of the battery cell 100.

[0603] In some embodiments, the first adhesive layer 4112 includes a latex acrylic layer, an ethylene acrylic acid copolymer layer, a latex layer, or a latex layer.

[0604] The acrylic layer may refer to a layer structure made of acrylic acid. It is understandable that the acrylic layer may be made of acrylic acid alone or may be made by mixing acrylic acid with other materials.

[0605] The ethylene acrylic acid copolymer layer may refer to a layer structure made of ethylene acrylic acid copolymer. It is understandable that the ethylene acrylic acid copolymer layer may be made of only ethylene acrylic acid copolymer or may be made by mixing ethylene acrylic acid copolymer with other materials.

[0606] The latex layer may refer to a layer structure made of latex. It is understandable that the latex layer may be made of latex alone or may be made by mixing latex with other materials.

[0607] The rubber layer may refer to a layer structure made of rubber. It is understandable that the rubber layer may be made of rubber alone or may be made by mixing rubber with other materials.

[0608] The first adhesive layer 4112 includes one or more of an acrylic layer, an ethylene acrylic acid copolymer layer, a latex layer, and a latex layer latex.

[0609] By adopting the technical solution of this embodiment, the first adhesive layer 4112 adopts the above-mentioned structure. During the charging and discharging process of the battery cell 100, the first adhesive layer 4112 can maintain a stable structural form and is not prone to melting. The first insulating member 41 can be stably bonded to the first weld mark 51, reducing the risk of the first insulating member 41 falling off, which is beneficial to improving the reliability of the battery cell 100.

[0610] In some embodiments, see Figures 19-21 As shown, the thickness of the first adhesive layer 4112 ranges from 1 μm to 7 μm.

[0611] The thickness of the first adhesive layer 4112 is T2, where 1 μm ≤ T2 ≤ 7 μm.

[0612] The value of T2 may be 1 μm, 7 μm, or any value between 1 μm and 7 μm. For example, the value of T2 may be, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, or 7 μm.

[0613] By adopting the technical solution of this embodiment, the design of the first adhesive layer 4112 having a thickness greater than or equal to 1 μm enables the first adhesive layer 4112 to stably bond the second phase change heat storage layer 4113 and the first weld mark 51 together, reducing the risk of the first insulating member 41 falling off and improving the reliability of the battery cell 100; the design of the first adhesive layer 4112 having a thickness less than or equal to 7 μm can reduce the risk of glue overflow in the first adhesive layer 4112.

[0614] In some embodiments, see Figures 19-21 As shown, the thickness of the first insulating base layer 4111 is in the range of 1 μm to 10 μm.

[0615] The thickness of the first insulating base layer 4111 is T3, where 1 μm≤T3≤10 μm.

[0616] The value of T3 may be 1 μm, 10 μm, or any value between 1 μm and 10 μm; for example, the value of T3 may be, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm.

[0617] By adopting the technical solution of this embodiment, the design of the first insulating base layer 4111 having a thickness greater than or equal to 1 μm enables the first insulating base layer 4111 to better block the burrs of the first weld mark 51, thereby improving the reliability of the battery cell 100; the design of the first insulating base layer 4111 having a thickness less than or equal to 10 μm reduces the space occupied and the weight of the first insulating base layer 4111, which is conducive to improving the energy density of the battery cell 100.

[0618] In some embodiments, see Figure 7 As shown, the current collector 10 further includes a conductive protection layer 13 , at least a portion of which is located between the active material layer 20 and the first metal portion 121 .

[0619] In some examples, the conductive protective layer 13 may be a conductive structure disposed between the active material layer 20 and the first metal portion 121. This conductive structure is electrically conductive, enabling electrons to be transferred between the active material layer 20 and the metal layer 12, 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.

[0620] For example, a portion of the conductive protection layer 13 is located between the active material layer 20 and the first metal portion 121 , and another portion covers the transition portion 1221 and protrudes out of the active material layer 20 .

[0621] Illustratively, the entire conductive protection layer 13 is located between the active material layer 20 and the first metal part 121 .

[0622] 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 metal layer 12, 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 metal layer 12, thereby improving the electron transmission capacity of the metal layer 12 and improving the fast charging performance of the battery cell 100.

[0623] During the rolling process of the first electrode 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 metal layer 12 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 metal layer 12, thereby protecting the metal layer 12, reducing the risk of cracks in the metal layer 12 caused by rolling the active material layer 20, and helping to improve the current carrying capacity of the metal layer 12.

[0624] In some embodiments, see Figure 7 As shown, along the direction from the first metal portion 121 to the second metal portion 122 , the conductive protection layer 13 protrudes from the end portion of the active material layer 20 close to the second metal portion 122 .

[0625] In some examples, a portion of the conductive protective layer 13 covers the first metal portion 121, and another portion covers the transition portion 1221. 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.

[0626] 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.

[0627] In some embodiments, see Figure 7 As shown, the thickness of at least a portion of the first metal portion 121 is smaller than the thickness of the second metal portion 122 .

[0628] The minimum thickness of the first metal portion 121 is t1 , and the thickness of the second metal portion 122 is t2 , where t1 < t2 .

[0629] In some examples, the second metal portion 122 has a uniform thickness or substantially uniform thickness structure, the first metal portion 121 also has a uniform thickness or substantially uniform thickness structure, and the thickness of the second metal portion 122 is greater than the minimum thickness of the first metal portion 121 .

[0630] In some examples, the second metal part 122 is a structure of equal thickness or a structure of substantially equal thickness, and the first metal part 121 may be a structure of unequal thickness. The thickness of the first metal part 121 is set to increase along the direction from the first metal part 121 to the second metal part 122. Specifically, it can be a step-by-step increase or a slow increase. The thickness of the part of the first metal part 121 away from the transition part 1221 is less than the thickness of the second metal part 122.

[0631] By adopting the technical solution of this embodiment, the thickness of the second metal part 122 can be greater than the thickness of at least part of the first metal part 121. The large thickness of the second metal part 122 improves the current-carrying capacity of the second metal part 122, reduces the heat generation of the second metal part 122, reduces the melting risk of the first insulating part 41, and improves the reliability of the battery cell 100. In addition, the current-carrying capacity of the second metal part 122 is also improved, which is also conducive to improving the fast charging performance of the battery cell 100.

[0632] In some embodiments, see Figure 7 As shown, the first metal part 121 includes a first sub-part 1211 and a second sub-part 1212, the first sub-part 1211 is connected between the second sub-part 1212 and the second metal part 122, the first sub-part 1211 and the second sub-part 1212 are covered with an active material layer 20, the thickness of the first sub-part 1211 is greater than the thickness of the second sub-part 1212, and the thickness of the second metal part 122 is greater than or equal to the thickness of the first sub-part 1211.

[0633] The first metal part 121 can be a structure of unequal thickness. Along the direction from the first metal part 121 to the second metal part 122, the first metal part 121 is divided into two parts. The part close to the second metal part 122 is the first sub-part 1211, and the part away from the second metal part 122 is the second sub-part 1212. Both the first sub-part 1211 and the second sub-part 1212 are covered with an active material layer 20.

[0634] In some examples, the first sub-section 1211 may be an equal-thickness structure, and the second sub-section 1212 may be an equal-thickness structure; the thickness of the first sub-section 1211 is greater than the thickness of the second sub-section 1212, and the thickness of the second metal section 122 is greater than or equal to the thickness of the first sub-section 1211, wherein the thickness of the first sub-section 1211 is t3, and the thickness of the second sub-section 1212 is t4, t3>t4, t2≥t3, t1=t4; the first sub-section 1211 and the second sub-section 1212 form a step structure; the thickness of the second metal section 122 may be equal to the thickness of the first sub-section 1211, so that the second metal section 122 and the first sub-section 1211 form an equal-thickness structure; or, the thickness of the second metal section 122 may be greater than the thickness of the second sub-section 1212, so that the first sub-section 1211 and the second metal section 122 form a step structure.

[0635] In some examples, the first sub-section 1211 may also have a multi-segment structure, with the thickness of each segment increasing in sequence along the direction from the first metal section 121 to the second metal section 122. For example, the first sub-section 1211 includes a first segment and a second segment, with the first segment located between the second segment and the second sub-section 1212. The thickness of the first segment gradually increases along the direction from the first metal section 121 to the second metal section 122, while the second segment is generally of uniform thickness, with the thickness of the second segment equal to the thickness of the second metal section 122, 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 1212 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 1212, thereby reducing stress concentration and improving structural strength. The thickness of the first segment may be equal to the thickness of the second metal section 122, and the thickness of the second metal section 122 may also be greater than the thickness of the first segment.

[0636] During the use of the battery cell 100, the electrons generated by the active material layer 20 are gradually gathered on the second metal part 122 through the first metal part 121 along the direction from the first metal part 121 to the second metal part 122. The electrons flowing through the first sub-part 1211 are more than the electrons flowing through the second sub-part 1212, which requires that the current flow capacity of the first sub-part 1211 is greater than the current flow capacity of the second sub-part 1212.

[0637] The thickness of the first sub-section 1211 in the embodiment of the present application is greater than the thickness of the second sub-section 1212, so that the current flow capacity of the first sub-section 1211 is greater than the current flow capacity of the second sub-section 1212. 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.

[0638] In some embodiments, see Figure 7As 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 1211 and the active material layer 20, and the second protective portion 132 is located between the second sub-portion 1212 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.

[0639] In some examples, along the first direction, the portion of the conductive protection layer 13 located between the first sub-portion 1211 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 1212 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.

[0640] 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 .

[0641] For example, the first protective portion 131 includes a first portion and a second portion. The first portion is located between the aforementioned first section and the active material layer 20, the second portion is located between the aforementioned second section and the active material layer 20, and the second protective portion 132 is located between the second sub-portion 1212 and the active material layer 20. Along the direction from the first metal portion 121 to the second metal portion 122, the thickness of the first portion gradually decreases, while the second portion is generally of uniform thickness. This allows the thickness of the first protective portion 131 to match the thickness of the first sub-portion 1211, making the surface of the conductive protective layer 13 facing away from the insulating substrate 11 nearly flat. Here, t5 is equal to the thickness of the second portion.

[0642] 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.

[0643] In some embodiments, see Figure 7 As shown, the conductive protection layer 13 further includes a third protection portion 133 , which covers the surface of the second metal portion 122 facing away from the insulating base 11 . The thickness of the third protection portion 133 is less than or equal to that of the first protection portion 131 .

[0644] In some examples, along the first direction, the conductive protection layer 13 can be divided into three parts: a portion close to the conductive member 30 is a third protection portion 133, a portion away from the conductive member 30 is a second protection portion 132, and a portion in the middle is a first protection portion 131. The thickness of the third protection portion 133 is t7, where t7 ≤ t5 < t6. Furthermore, the thickness of the second metal portion 122 is greater than or equal to the thickness of the first sub-portion 1211. This can reduce the thickness difference between the first protection portion 131 and the third protection portion 133 of the current collector 10, helping the surface of the conductive protection layer 13 facing away from the metal layer 12 to be closer to a plane. The third protection portion 133 can cover the transition portion 1221.

[0645] For example, the second protective portion 132, the third protective portion 133, the second metal portion 122 and the second sub-portion 1212 are all structures of equal thickness, and the first sub-portion 1211 and the first protective portion 131 are both structures of unequal thickness; the thickness of the first sub-portion 1211 and the thickness of the first protective portion 131 are adapted to make the surface of the conductive protective layer 13 facing away from the insulating substrate 11 close to a plane.

[0646] 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.

[0647] The battery cell 100 of the present application is described below in conjunction with some embodiments.

[0648] Example 1

[0649] See Figures 3 to 11 and Figure 18 As shown, in this embodiment, 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.

[0650] 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.

[0651] 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.

[0652] In this embodiment, the metal layer 12 includes a first metal part 121 and a second metal part 122, the second metal part 122 includes a transition part 1221 and at least one protrusion 1222, the protrusion 1222, the transition part 1221 and the first metal part 121 are arranged along a first direction, the transition part 1221 is connected between the first metal part 121 and the protrusion 1222, the active material layer 20 covers the first metal part 121, the protrusion 1222 and the transition part 1221 are not covered with the active material layer 20, and the first direction is perpendicular to the thickness direction of the current collector 10.

[0653] 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 and the second metal portion 122 are welded 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.

[0654] In this embodiment, the first weld mark 51 includes a first weld mark portion 511. The protruding portion 1222 includes a first protruding sub-portion 12221 and a second protruding sub-portion 12222. The first protruding sub-portion 12221 is connected between the second protruding sub-portion 12222 and the transition portion 1221. The dimension of the second protruding sub-portion 12222 along the second direction is smaller than the dimension of the first protruding sub-portion 12221 along the second direction. The first protruding sub-portion 12221 is welded to the first connecting portion 31 to form a first weld mark sub-portion 5111. The second protruding sub-portion 12222 is welded to the first connecting portion 31 to form a second weld mark sub-portion 5112. The first weld mark sub-portion 5111 and the second weld mark sub-portion 5112 form the first weld mark portion 511. The second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0655] In this embodiment, there are multiple protrusions 1222 , and the multiple protrusions 1222 are arranged at intervals along the second direction, which is perpendicular to the first direction and the thickness direction of the current collector 10 .

[0656] In this embodiment, the electrode assembly 101 includes a first insulating member 41 , and the first insulating member 41 covers the first weld mark 51 and the second weld mark 52 .

[0657] In this embodiment, the first insulating member 41 includes a plurality of first insulating portions 4121. Along the first direction, one side of the first insulating portion 4121 covers the second weld mark 52, and the other side of the first insulating portion 4121 covers the transition portion 1221. The plurality of first insulating portions 4121 are sequentially connected along the second direction to form a whole. The first insulating portions 4121 cover the protrusion 1222 one by one, and the portions of the two adjacent first insulating portions 4121 and the transition portion 1221 corresponding to the area where the protrusion 1222 is not led out form a blocking portion 4131; the blocking portions 4131 of the two first insulating members 41 are in contact with each other.

[0658] In this embodiment, the electrode assembly 101 further includes a second insulating member 42, which covers the surface of the second metal portion 122 facing away from the insulating substrate 11. The second insulating member 42 is located between the first connecting portion 31 and the active material layer 20, and the first insulating member 41 covers the second insulating member 42. The second insulating member 42 serves as the first phase-change heat storage layer.

[0659] Example 2

[0660] The difference between this embodiment and the first embodiment is that: Figures 12-16 As shown, the first weld mark 51 includes a first weld mark portion 511 and a second weld mark portion 512, the first connecting portion 31 also includes a 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 and the protruding portion 1222 are welded to form the first weld mark portion 511, and the second connecting sub-portion 312 and the transition portion 1221 are welded to form the second weld mark portion 512.

[0661] In this embodiment, the first insulating member 41 further includes a second insulating portion 4122 . The second insulating portion 4122 is connected to the first insulating portion 4121 and covers the second weld portion 512 .

[0662] Example 3

[0663] The difference between this embodiment and the first embodiment is that: Figure 17 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 .

[0664] Example 4

[0665] The difference between this embodiment and the first embodiment is that: Figure 19 and Figure 20 As shown, the first insulating member 41 includes a first insulating base 11 and a first adhesive layer 4112 , and the first adhesive layer 4112 is bonded between the first weld mark 51 and the first insulating base 11 .

[0666] Example 5

[0667] The difference between this embodiment and the fourth embodiment is that: Figure 21 As shown, the first insulating member 41 includes a second phase-change heat storage layer 4113 , which is located between the first adhesive layer 4112 and the second insulating base layer. The adhesive layer is bonded between the first weld mark 51 and the second phase-change heat storage layer 4113 .

[0668] In some embodiments, see Figure 2 As shown, a battery device 1100 is provided, including the battery cell 100 of the above embodiment.

[0669] 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.

[0670] In some embodiments, see Figure 1 As shown, an electrical device is provided, including the battery device 1100 according to the above embodiment.

[0671] 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, which is beneficial to improving the reliability of the electrical device.

[0672] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other and will not be repeated herein for the sake of brevity.

[0673] 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 disposed within the housing, the electrode assembly comprising a first electrode sheet, the first electrode sheet comprising a current collector, a conductive member, and an active material layer, the conductive member being electrically connected to the electrode lead; The current collector includes an insulating substrate and a metal layer, wherein 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 first metal portion and a second metal 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 first metal portion is covered with the active material layer, and at least a portion of the second metal portion is not covered with the active material layer; the conductive member is welded to a surface of the second metal portion facing away from the insulating substrate to form a first weld mark; The electrode assembly includes a first insulating member covering at least a portion of the first weld mark.

2. The battery cell according to claim 1, wherein: Along the direction from the first metal part to the second metal part, the first insulating part protrudes from the edge of the first weld mark away from the active material layer; and / or, along the direction from the second metal part to the first metal part, the first insulating part protrudes from the edge of the first weld mark close to the active material layer.

3. The battery cell according to claim 1, wherein: The conductive component includes a first connecting portion and at least one second connecting portion, the first connecting portion and the second connecting portion are connected, the second connecting portion is electrically connected to the electrode lead portion, and the first connecting portion is welded to the surface of the second metal portion facing away from the insulating substrate to form the first weld mark.

4. The battery cell according to claim 3, wherein: The second metal portion includes at least one protrusion; Along a second direction, the sum of sizes of all the protrusions is smaller than a size of the first metal portion, wherein 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 first connecting sub-portion, the first connecting sub-portion is connected to the second connecting portion, the first connecting sub-portion covers the surface of the protrusion facing away from the insulating base, and the first connecting sub-portion corresponds to the protrusion one-to-one.

5. The battery cell according to claim 4, characterized in that: The first insulating member includes at least one first insulating portion, the first insulating portion covers a surface of the first connecting sub-portion facing away from the protruding portion, and the first connecting sub-portions correspond to each other one by one.

6. The battery cell according to claim 5, characterized in that: The first weld print includes at least one first weld print portion, and the first connecting sub-portion is welded to the surface of the protruding portion facing away from the insulating base to form the first weld print portion; The first insulating portion covers at least a portion of the first weld print portion.

7. The battery cell according to claim 6, characterized in that: The protruding portion includes a first protruding sub-portion and a second protruding sub-portion, wherein the first protruding sub-portion is connected between the second protruding sub-portion and the first metal portion; along the second direction, the size of the first protruding sub-portion is larger than the size of the second protruding sub-portion; The first weld print portion includes a first weld print sub-portion, the first connecting portion is welded to the first protruding sub-portion to form the first weld print sub-portion, and the first insulating portion covers at least a portion of the first weld print portion; And / or, the first weld print portion includes a second weld print sub-portion, the first connection portion is welded to the second protruding sub-portion to form the second weld print sub-portion, and the first insulating portion covers at least a portion of the second weld print sub-portion.

8. The battery cell according to claim 6, wherein: Along the direction from the first metal portion to the second metal portion, the first insulating portion protrudes from the edge of the first weld print portion away from the active material layer; and / or, along the direction from the second metal portion to the first metal portion, the first insulating portion protrudes from the edge of the first weld print portion close to the active material layer.

9. The battery cell according to claim 6, characterized in that: Along the second direction, two opposite side surfaces of the protruding portion are flush with two opposite side surfaces of the corresponding first connecting sub-portion, and two opposite edges of the first welding portion are flush with two opposite side surfaces of the corresponding first connecting sub-portion.

10. The battery cell according to claim 5, characterized in that: Along the second direction, at least one of the two opposite sides of the first insulating portion protrudes from a side surface of the corresponding first connecting sub-portion located on the same side.

11. The battery cell according to claim 5, characterized in that: Along the direction from the first metal part to the second metal part, the first insulating part protrudes from the side of the corresponding first connecting sub-part away from the active material layer; and / or, along the direction from the second metal part to the first metal part, the first insulating part protrudes from the side of the corresponding first connecting sub-part close to the active material layer.

12. The battery cell according to claim 5, characterized in that: There are multiple protrusions, the first connecting portion includes multiple first connecting sub-portions, the multiple protrusions are arranged at intervals along the second direction, and the multiple first connecting sub-portions are arranged at intervals along the second direction; there are multiple second connecting portions, the multiple second connecting portions are arranged at intervals along the second direction, and the first connecting sub-portions are connected one-to-one with the second connecting portions.

13. The battery cell according to claim 12, characterized in that: Two adjacent first insulating parts are disconnected or connected.

14. The battery cell according to any one of claims 3 to 13, characterized in that: The second metal portion includes a transition portion and at least one protruding portion, wherein the transition portion is connected between the protruding portion and the first metal portion; Along a second direction, a size of the transition portion is greater than a sum of sizes of all the protruding portions, wherein the second direction is perpendicular to the first direction and a thickness direction of the current collector.

15. The battery cell according to claim 14, characterized in that: Along the second direction, a size of the first metal portion is L1, a size of the transition portion is L2, and 0.8≤L2 / L1≤1.

16. The battery cell according to claim 14, characterized in that: The first weld print includes a second weld print portion, the first connecting portion includes a second connecting sub-portion connected to the second connecting portion, and the second connecting sub-portion is welded to the transition portion to form the second weld print portion.

17. The battery cell according to claim 16, characterized in that: Along the second direction, a size of the transition portion is L2, a size of the second weld print portion is L3, and 0.8≤L3 / L2≤1.

18. The battery cell according to claim 16, characterized in that: The side of the transition portion facing away from the first metal portion, the edge of the second weld portion away from the active material layer, and the side of the second connecting sub-portion facing away from the active material layer are flush.

19. The battery cell according to claim 16, wherein: The first insulating member includes a second insulating portion, and the second insulating portion covers at least a portion of the second weld print portion.

20. The battery cell according to claim 19, characterized in that: Along the direction from the first metal portion to the second metal portion, the second insulating portion protrudes from the edge of the second weld print portion away from the active material layer; and / or, along the direction from the second metal portion to the first metal portion, the second insulating portion protrudes from the edge of the second weld print portion close to the active material layer.

21. The battery cell according to claim 19, wherein: Along the direction from the first metal portion to the second metal portion, the second insulating portion protrudes from a side of the second connecting sub-portion away from the active material layer.

22. The battery cell according to claim 19, wherein: Along the second direction, two opposite side surfaces of the transition portion are flush with two opposite side surfaces of the second connecting sub-portion, and two opposite edges of the second welded portion are flush with two opposite side surfaces of the second connecting sub-portion.

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

24. The battery cell according to claim 19, wherein: Along the direction from the first metal part to the second metal part, the second insulating part protrudes from the side of the second connecting sub-part facing away from the active material layer; and / or, along the direction from the second metal part to the first metal part, the second insulating part protrudes from the side of the second connecting sub-part facing the active material layer.

25. The battery cell according to claim 19, wherein: The first connecting portion includes at least one first connecting sub-portion, the first connecting sub-portion being connected between the second connecting portion and the second connecting sub-portion, the first connecting sub-portion covering the surface of the protruding portion facing away from the insulating base, and the first connecting sub-portion corresponding to the protruding portion one-to-one; The first insulating member includes at least one first insulating portion, the first insulating portion is connected to the second insulating portion, the first insulating portion covers the surface of the first connecting sub-portion facing away from the protruding portion, and the first insulating portion corresponds to the first connecting sub-portion one-to-one.

26. The battery cell according to claim 25, characterized in that: There are multiple protrusions, and the multiple protrusions are arranged at intervals along the second direction; there are multiple first connecting sub-parts, and the multiple first connecting sub-parts are arranged at intervals along the second direction; there are multiple second connecting parts, and the multiple second connecting parts are arranged at intervals along the second direction; the first connecting sub-parts are connected to the second connecting parts in a one-to-one correspondence, and the multiple first connecting sub-parts are connected to the side of the second connecting sub-part facing away from the active material layer; the second connecting sub-parts are continuously arranged along the second direction.

27. The battery cell according to claim 16, wherein: The electrode assembly further includes a second electrode piece having a polarity opposite to that of the first electrode piece, the second electrode piece including a main functional portion and an electrode ear portion arranged along the first direction, the main functional portion having a first end surface at an end adjacent to the second metal portion, and the electrode ear portion extending outward from the first end surface; Along the direction from the first metal portion to the second metal portion, a side portion of the second connecting sub-portion away from the active material layer does not protrude beyond the first end surface; Alternatively, along the thickness direction of the current collector, the projection of the first end surface is located within the projection of the second connecting sub-portion.

28. The battery cell according to any one of claims 3 to 13, characterized in that: Along the direction from the first metal part to the second metal part, the first insulating part protrudes from the side of the first connecting part away from the active material layer; and / or, along the direction from the second metal part to the first metal part, the first insulating part protrudes from the side of the first connecting part close to the active material layer.

29. The battery cell according to any one of claims 3 to 13, characterized in that: Along the first direction, the first weld mark is spaced apart from the active material layer.

30. The battery cell according to claim 29, wherein: The electrode assembly further includes a second insulating member, which covers a surface of the second metal portion facing away from the insulating substrate, and is located between the first weld mark and the active material layer.

31. The battery cell according to claim 30, characterized in that: Along the first direction, the first connection portion is spaced apart from the active material layer.

32. The battery cell according to claim 31, characterized in that: At least a portion of the second insulating member is located between the first connecting portion and the active material layer.

33. The battery cell according to claim 32, characterized in that: The electrode assembly further includes a second electrode piece having a polarity opposite to that of the first electrode piece, the second electrode piece including a main functional portion and an electrode ear portion arranged along the first direction, the main functional portion having a first end surface at an end adjacent to the second metal portion, and the electrode ear portion extending outward from the first end surface; Along the thickness direction of the current collector, the projection of the first end surface is located within the projection of the second insulating member.

34. The battery cell according to claim 30, wherein: Along the first direction, one side of the first insulating member covers the first weld mark, and the other side of the first insulating member covers at least a portion of the second insulating member.

35. The battery cell according to claim 30, wherein: The second insulating member includes a first phase-change heat storage layer, and the first phase-change heat storage layer covers a surface of the second metal portion facing away from the insulating substrate.

36. The battery cell according to claim 35, characterized in that: The first phase-change heat storage layer includes an organic heat storage material layer or an inorganic heat storage material layer.

37. The battery cell according to claim 35, characterized in that: The first phase-change heat storage layer includes an organic heat storage material layer, and the organic heat storage material layer includes a fatty acid layer, a paraffin layer, a straight-chain alkane layer, a fatty alcohol layer or an ester material layer.

38. The battery cell according to claim 35, wherein: The first phase-change heat storage layer includes an inorganic heat storage material layer, and the inorganic heat storage material layer includes a nitrate layer, a carbonate layer, a fluoride salt layer or a hydrochloride layer.

39. The battery cell according to any one of claims 2 to 13, characterized in that: Along the first direction, one side of the first insulating member covers the first weld mark, and the other side of the first insulating member covers the active material layer.

40. The battery cell according to any one of claims 3 to 13, characterized in that: There are two metal layers, and the two metal layers cover opposite sides of the insulating substrate along the thickness direction of the current collector. There are two active material layers, and the two active material layers cover the first metal portions of the two metal layers respectively. There are two conductive members, and the first connection portions of the two conductive members are respectively welded to the second metal portions of the two metal layers to form two first weld marks; The number of the first insulating members is two, and the two first insulating members respectively cover the two first weld marks.

41. The battery cell according to claim 40, characterized in that: Along the direction from the first metal part to the second metal part, the first insulating member protrudes from the metal layer 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.

42. The battery cell according to claim 41, characterized in that: The blocking portions of the two first insulating members are in contact with each other.

43. The battery cell according to claim 40, characterized in that: The second connection portions of the two conductive members are welded to form a second weld mark.

44. The battery cell according to claim 43, characterized in that: The first insulating member covers at least a portion of the second weld mark.

45. The battery cell according to claim 44, characterized in that: Along a direction from the first metal portion to the second metal portion, the first insulating member protrudes from an edge of the second weld mark away from the active material layer.

46. ​​The battery cell according to any one of claims 1 to 13, 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 second metal 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.

47. The battery cell according to any one of claims 1 to 13, characterized in that: The glass transition temperature of the first insulating member is greater than or equal to 150°C. Optionally, the glass transition temperature of the first insulating member is greater than or equal to 200°C.

48. The battery cell according to any one of claims 1 to 13, characterized in that: The specific heat capacity of the first insulating member is greater than or equal to 1.2 J / g·°C.

49. The battery cell according to any one of claims 1 to 13, characterized in that: The first insulating member includes a first insulating base layer and a first adhesive layer, wherein the first adhesive layer is bonded between the first weld mark and the first insulating base layer.

50. The battery cell according to claim 49, wherein: The first insulating member further includes a second phase-change heat storage layer connected between the first insulating base layer and the first adhesive layer, and the first adhesive layer is bonded between the second phase-change heat storage layer and the first weld print.

51. The battery cell according to claim 50, characterized in that: The second phase-change heat storage layer includes an organic heat storage material layer or an inorganic heat storage material layer.

52. The battery cell according to claim 50, characterized in that: The second phase-change heat storage layer includes an organic heat storage material layer, and the organic heat storage material layer includes a fatty acid layer, a paraffin layer, a straight-chain alkane layer, a fatty alcohol layer or an ester material layer.

53. The battery cell according to claim 50, characterized in that: The second phase-change heat storage layer includes an inorganic heat storage material layer, and the inorganic heat storage material layer includes a nitrate layer, a carbonate layer, a fluoride salt layer or a hydrochloride layer.

54. The battery cell according to claim 50, characterized in that: The thickness of the second phase-change heat storage layer is in the range of 1 μm to 5 μm.

55. The battery cell according to claim 50, characterized in that: The glass transition temperature of the first adhesive layer is greater than the phase change temperature of the second phase change heat storage layer, and / or the glass transition temperature of the first insulating base layer is greater than the phase change temperature of the second phase change heat storage layer.

56. The battery cell according to claim 50, wherein: The first insulating base layer includes a polypropylene layer, a polyethylene terephthalate layer, an aramid 1313 layer, a polyvinylidene fluoride layer or a cellulose layer.

57. The battery cell according to claim 50, characterized in that: The first adhesive layer includes a latex acrylic layer, an ethylene acrylic acid copolymer layer, a latex layer, or a latex layer.

58. The battery cell according to claim 50, characterized in that: The thickness of the first adhesive layer is in the range of 1 μm to 7 μm.

59. The battery cell according to claim 50, characterized in that: The thickness of the first insulating base layer ranges from 1 μm to 10 μm.

60. The battery cell according to any one of claims 1 to 13, characterized in that: The current collector further includes a conductive protective layer, at least a portion of which is located between the active material layer and the first metal part.

61. The battery cell according to claim 60, characterized in that: Along a direction from the first metal portion to the second metal portion, the conductive protection layer protrudes from an end portion of the active material layer close to the second metal portion.

62. The battery cell according to any one of claims 1 to 13, characterized in that: The thickness of at least a portion of the first metal portion is smaller than the thickness of the second metal portion.

63. The battery cell according to claim 62, characterized in that: The first metal part includes a first sub-part and a second sub-part, the first sub-part is connected between the second sub-part and the second metal part, the first sub-part and the second sub-part are covered with the active material layer, the thickness of the first sub-part is greater than the thickness of the second sub-part, and the thickness of the second metal part is greater than or equal to the thickness of the first sub-part.

64. The battery cell according to claim 63, 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.

65. The battery cell according to claim 64, characterized in that: The conductive protection layer further includes a third protection portion, which covers a surface of the second metal 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.

66. A battery device, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 65.

67. An electrical device, characterized in that: A battery device comprising the battery device of claim 66.

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