Battery cell, battery device, and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device. The battery cell includes a housing and an electrode assembly. The shell is provided with an electrode leading-out part. The electrode assembly is contained in the shell and comprises a first pole piece and a first insulating part. The first pole piece includes a conductive member, a current collector, and an active material layer. The current collector comprises an insulating substrate and a metal layer, at least part of the metal layer is located between the insulating substrate and the active material layer, and the conductive component is used for electrically connecting the metal layer and the electrode lead-out part. The conductive member includes a first connection portion located on a side of the metal layer facing away from the insulating substrate and connected to the metal layer, and the first insulating component is attached to the first connection portion. The first insulating member protrudes from a first end surface of the first connecting portion facing the active material layer in a direction in which the first connecting portion points to the active material layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to international patent application PCT / CN2024 / 106988, filed on July 23, 2024, entitled “Battery Cell, Battery Device, and Electrical Device,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and more particularly, to a battery cell, a battery device, and an electrical device. Background Art

[0004] 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.

[0005] In the development of battery technology, how to improve the reliability of battery cells is a research direction in battery technology. Utility Model Content

[0006] The present application provides a battery cell, a battery device, and an electrical device, which can improve reliability.

[0007] In a first aspect, embodiments of the present application provide a battery cell comprising a housing and an electrode assembly. The housing is provided with an electrode lead-out portion. At least a portion of the electrode assembly is housed within the housing, and the electrode assembly comprises a first electrode sheet and a first insulating component. The first electrode sheet comprises a conductive member, a current collector, and an active material layer. The current collector comprises an insulating substrate and a metal layer, the insulating substrate, the metal layer, and the active material layer being stacked along the thickness of the current collector, with at least a portion of the metal layer located between the insulating substrate and the active material layer. The conductive member is configured to electrically connect the metal layer to the electrode lead-out portion. The conductive member comprises a first connecting portion, the first connecting portion being located on a side of the metal layer facing away from the insulating substrate and connected to the metal layer. The active material layer and the first connecting portion are arranged along a first direction perpendicular to the thickness of the current collector. At least a portion of the first insulating component is located on a side of the first connecting portion facing away from the metal layer and attached to the first connecting portion. Along the direction from the first connecting portion toward the active material layer, the first insulating component protrudes from a first end face of the first connecting portion facing the active material layer.

[0008] The current collector adopts a composite structure of an insulating matrix and a metal layer. Compared with a pure metal current collector, the thickness of the metal layer is smaller. When the current collector is accidentally punctured, the burrs generated by the metal layer are smaller, and the burrs of the metal layer are not easy to pierce other components, thereby reducing the risk of short circuits and helping to improve the reliability of the battery cell. During the normal use of the battery cell, the first insulating component can block the burrs at the first end face, reducing the possibility of the burrs at the first end face piercing other components, reducing the risk of short circuits, and improving the reliability of the battery cell. For example, the electrode assembly also includes a second pole piece and an isolating member. The first insulating member can block the burrs at the first end face, reducing the possibility of the burrs piercing the isolating member and contacting the second pole piece, thereby reducing the risk of short circuits.

[0009] In some embodiments, the first connecting portion and the active material layer are spaced apart along the first direction. Spaced apart from each other, the first connecting portion and the active material layer can reduce the mutual influence between the two and improve the reliability of the battery cell.

[0010] In some embodiments, the first insulating member at least partially covers the region of the metal layer between the first connecting portion and the active material layer. The first insulating member can isolate the region of the metal layer not covered by the first connecting portion and the active material layer from the second electrode sheet, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0011] In some embodiments, a portion of the first insulating component is located between the first connecting portion and the active material layer along the first direction. The portion of the first insulating component located between the first connecting portion and the active material layer is attached to the metal layer. Attaching the first insulating component to the metal layer can increase the connection strength between the first insulating component and the first electrode piece and reduce the risk of the first insulating component falling off. The portion of the first insulating component attached to the metal layer can shield the metal layer, improving insulation, reducing the risk of electrical conduction between the metal layer and the second electrode piece, and improving reliability.

[0012] In some embodiments, the electrode assembly includes a second insulating component, which is disposed on the surface of the metal layer facing away from the insulating substrate. In the first direction, at least a portion of the second insulating component is located between the first connecting portion and the active material layer. The second insulating component can support the portion of the metal layer located between the first connecting portion and the active material layer, thereby reducing damage such as cracks and fractures that may occur in this portion during the manufacturing process of the battery device, which is beneficial to improving the electron transmission capacity of this portion of the metal layer and improving the fast charging performance and reliability of the battery cell. In addition, the second insulating component can also separate the area of the metal layer that is not covered by the first connecting portion and the active material layer from the second electrode, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0013] In some embodiments, a portion of the first insulating component is located on a side of the second insulating component facing away from the metal layer and is connected to the second insulating component. Connecting the first insulating component to the second insulating component can reduce the risk of the first insulating component falling off. The first and second insulating components can jointly cover the metal layer, thereby improving insulation, reducing the risk of electrical contact between the metal layer and the second electrode, and enhancing reliability.

[0014] In some embodiments, the first insulating component is further connected to the active material layer to improve the connection strength between the first insulating component and the first pole piece, reduce the risk of the first insulating component falling off from the first pole piece, and improve reliability.

[0015] In some embodiments, the first insulating component covers a portion of the active material layer. The first insulating component can cover the edge region of the active material layer to constrain the edge region of the active material layer and reduce the risk of collapse or falling off of the edge region of the active material layer due to stress concentration.

[0016] In some embodiments, the portion of the first insulating component covering the active material layer is configured to allow ions to pass through, thereby reducing the first insulating component's barrier to ions and reducing capacity loss of the first electrode.

[0017] In some embodiments, a portion of the first insulating component covering the active material layer is provided with a through hole, which can serve as a channel for ions to pass through.

[0018] In some embodiments, the first insulating component is configured to block ions from passing through. During charging, the first insulating component can block ions from passing through, thereby reducing the number of ions that move to the negative electrode active material layer and reducing the risk of ion precipitation.

[0019] In some embodiments, the active material layer includes a first active material portion and a second active material portion arranged along a first direction, the first active material portion being located on a side of the second active material portion facing the first connecting portion, the thickness of the first active material portion at an end away from the second active material portion being less than the thickness of the second active material portion, and the thickness of the first active material portion decreasing along the direction of the active material layer toward the first connecting portion. The first insulating member covers at least a portion of the first active material portion.

[0020] During the molding process of the first electrode sheet, the active material layer can be rolled to compact it. The provision of the first active material portion reduces the rolling pressure on the edges of the active material layer, reducing the risk of cracking at the edges. The first active material portion has a relatively small thickness, and covering the first insulating component with the first active material portion improves space utilization along the thickness of the current collector and reduces the pressure on the first insulating component during electrode assembly expansion, thereby reducing stress concentration and the risk of the active material layer being cracked by the first insulating component, thereby improving the cycling performance of the battery cell.

[0021] In some embodiments, along the first direction, the dimension of the portion of the first insulating component covering the active material layer is H, 0.2 mm ≤ H ≤ 1 mm. Limiting H to greater than or equal to 0.2 mm allows the first insulating component to protect the edge region of the active material layer, reducing the risk of material falling from the edge region of the active material layer. Limiting H to less than or equal to 1 mm limits the area of the active material layer covered by the first insulating component, reducing capacity loss. Limiting H to 0.2 mm-1 mm balances the reliability and energy density of the battery cell.

[0022] In some embodiments, the metal layer includes a first metal portion and a second metal portion arranged and connected along a first direction, the first metal portion being covered with an active material layer, and the second metal portion being uncovered. The first connecting portion is welded to the second metal portion to form a first weld mark. Welding the second metal portion to the first connecting portion can simplify the manufacturing process of the first electrode sheet and improve the flow capacity between the metal layer and the first connecting portion. By providing a second metal portion uncovered with the active material layer, the impact of welding on the active material layer can be reduced.

[0023] In some embodiments, the second metal portion includes at least one protrusion, and along the second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the first metal portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector. The first connecting portion includes at least one first connecting sub-portion, and the first connecting sub-portion is located on the side of the protrusion away from the insulating substrate, and the first connecting sub-portion corresponds one-to-one with the protrusion. By providing the protrusion, the space and volume occupied by the first pole piece can be reduced, and the energy density of the battery cell can be improved. By providing the first connecting sub-portion, the flow area between the first connecting portion and the second metal portion can be increased, and the flow capacity can be improved.

[0024] In some embodiments, the first insulating component includes at least one first insulator portion, which covers the surface of the first connector portion facing away from the protruding portion, and the first insulator portion corresponds to the first connector portion. The first insulator portion may cover the first connector portion to reduce the risk of electrical conduction between the first connector portion and the second electrode piece, thereby improving the reliability of the battery cell.

[0025] In some embodiments, the first insulating component further includes a second insulating portion connected to the first insulating portion. Along the first direction, the second insulating portion is located on the side of the first insulating portion facing the active material layer. The provision of the second insulating portion allows the first insulating component to protrude beyond the first connector portion in the direction from the first connector portion toward the active material layer, thereby reducing the risk of electrical conduction between the first connector portion and the second pole piece. Furthermore, the second insulating portion can also cover burrs on the first end surface, reducing the possibility of burrs piercing the separator and contacting the second pole piece, thereby reducing the risk of short circuits.

[0026] In some embodiments, the first insulating component further includes a third insulator portion connected to the first insulator portion, with the third insulator portion and the first insulator portion being arranged along the second direction. The provision of the third insulator portion allows the first insulating component to protrude beyond the first connector portion in the second direction, thereby covering burrs at the end of the first connector portion along the second direction, reducing the possibility of burrs piercing the separator and contacting the second pole piece, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0027] In some embodiments, the current collector includes two metal layers, which are disposed on opposite sides of the insulating substrate along the thickness direction of the current collector. The first pole piece includes two active material layers and two conductive members, the two active material layers are respectively disposed on the two metal layers, and the first connecting portions of the two conductive members are respectively connected to the second metal portions of the two metal layers. The electrode assembly includes two first insulating parts, which are respectively attached to the two first connecting parts. The two first insulating parts can respectively cover the burrs on the first end surfaces of the two first connecting parts, thereby reducing the possibility of the burrs piercing the separator and contacting the second pole piece, thereby reducing the risk of short circuit.

[0028] In some embodiments, the third insulator portions of the two first insulating components are bonded and / or connected. After the third insulator portions of the two first insulating components are bonded, metal debris at both ends of the first connecting sub-portion along the second direction can be encapsulated, preventing the metal debris from falling into the electrode assembly, thereby further reducing the risk of short circuits in the battery cells.

[0029] In some embodiments, the first insulating component further includes a fourth insulating portion connected to the first insulating portion, and along the first direction, the fourth insulating portion is located on a side of the first insulating portion facing away from the active material layer. The fourth insulating portion can improve insulation performance.

[0030] In some embodiments, the first connector is welded to the protrusion to form a first weld print, which includes the first weld print. The first insulator covers at least a portion of the first weld print. The first connector and the protrusion are connected by welding, which is simple and facilitates the production of the first pole piece. The first connector can directly pass current through the first weld print between the first connector and the protrusion, which helps improve the current flow capacity between the first connector and the protrusion. The first insulator can block burrs, metal debris, and other structures on the first weld print, thereby reducing the risk of these structures passing through the separator and contacting the second pole piece, which helps improve the reliability of the battery cell.

[0031] In some embodiments, along the first direction, both ends of the first weld print do not extend beyond the first insulator portion, thereby reducing the exposed area of the first weld print, lowering the risk of the first weld print puncturing the isolation piece, and improving the reliability of the battery cell.

[0032] In some embodiments, there are multiple protrusions, and the multiple protrusions are spaced apart along the second direction. The first connecting portion includes multiple first connecting sub-portions, and the multiple first connecting sub-portions are spaced apart along the second direction, and the multiple first connecting sub-portions correspond one-to-one with the multiple protrusions. By providing multiple protrusions and multiple first connecting sub-portions, the flow area between the first connecting portion and the second metal portion can be increased, thereby improving the flow capacity and the fast charging performance of the battery cell.

[0033] In some embodiments, the first insulating component includes a plurality of first insulator portions arranged along the second direction. The first insulator portions cover the surface of the first connector portion facing away from the protruding portion, and the first insulator portions are arranged in a one-to-one correspondence with the first connector portions. The plurality of first insulator portions respectively cover the plurality of first connector portions to reduce the risk of electrical conduction between the first connector portions and the second electrode piece, thereby improving the reliability of the battery cell.

[0034] In some embodiments, the first insulating component further includes a second insulator portion. The second insulator portion is located on the side of the plurality of first insulator portions facing the active material layer in the first direction. The second insulator portion extends continuously along the second direction and connects to the plurality of first insulator portions. The continuous arrangement of the second insulator portions can increase the insulation area and reduce the risk of short circuits. The second insulator portion connects the plurality of first insulator portions into a single unit, thereby reducing the risk of the first insulator portion falling off the first connecting sub-portion and improving insulation reliability.

[0035] In some embodiments, the first insulating component further includes multiple second insulator sections, each corresponding to the first insulator sections. Each first insulator section is connected to the corresponding second insulator section. In the first direction, the second insulator section is located on the side of the first insulator section facing the active material layer. Providing multiple second insulator sections can reduce the size of a single second insulator section, saving space and increasing energy density.

[0036] In some embodiments, the first insulating component includes multiple third insulator sections arranged along the second direction, with each first insulator section connected to two third insulator sections at both ends along the second direction. The two third insulator sections can cover burrs at both ends of the first connecting section along the second direction, thereby reducing the possibility of burrs piercing the separator and contacting the second pole piece, reducing the risk of short circuits, and improving the reliability of the battery cell.

[0037] In some embodiments, multiple first insulator sections and multiple third insulator sections are arranged alternately along the second direction, with two adjacent first insulator sections connected by a third insulator section. The multiple third insulator sections connect the multiple first insulator sections, increasing the insulation area while reducing the risk of the first insulator sections falling off the first connector section, thereby improving insulation reliability. The first insulating component is arranged continuously as a whole, which can restrain the first connector section, reduce deformation of the first connector section, and prevent the first connector section from being inserted upside down between the active material layer and the second electrode piece, thereby reducing the risk of short circuits.

[0038] In some embodiments, two third insulator sections are spaced apart between two adjacent first insulator sections along the second direction. The two third insulator sections located between the two adjacent first insulator sections are respectively connected to the two first insulator sections. The first insulating component forms a hollow region between the two third insulator sections, thereby reducing the weight and space occupied by the first insulating component and improving energy density.

[0039] In some embodiments, the first insulating component further includes multiple fourth insulator sections. The multiple first insulator sections and the multiple fourth insulator sections are provided in a one-to-one correspondence, with the first insulator sections connected to the corresponding fourth insulator sections. In the first direction, the fourth insulator sections are located on the side of the first insulator section facing away from the active material layer. Providing multiple fourth insulator sections can improve insulation performance.

[0040] In some embodiments, each first connecting sub-portion has a second end surface at one end facing the active material layer; the second end surfaces of the plurality of first connecting sub-portions form the first end surface. The first insulating component can block burrs on each second end surface, reducing the possibility of burrs on the second end surface piercing the separator and contacting the second electrode piece, thereby reducing the risk of short circuits.

[0041] In some embodiments, the second metal portion further includes a transition portion connected between the first metal portion and the protrusion. Along the second direction, the transition portion is larger than the sum of the dimensions of all protrusions. Providing the transition portion can increase the flow area and improve flow capacity.

[0042] In some embodiments, the first connecting portion includes a second connecting sub-portion, and the second connecting sub-portion is located on the side of the transition portion facing away from the insulating substrate along the thickness direction of the current collector, and the first connecting sub-portion is connected to the end face of the second connecting sub-portion away from the active material layer. Along the first direction, the end face of the second connecting sub-portion facing the active material layer is the first end face. During the cycle of the battery cell, a portion of the current can be transmitted between the transition portion and the second connecting sub-portion, thereby reducing the overcurrent pressure between the protrusion and the first connecting sub-portion, which is beneficial to reducing the heat generation of the protrusion and improving the fast charging performance and reliability of the battery cell. The first insulating component can block the burrs at the first end face, reduce the possibility of the burrs piercing the isolating member and contacting the second pole piece, and thus reduce the risk of short circuit.

[0043] In some embodiments, the first insulating component includes a second insulator portion that covers the second connecting sub-portion and protrudes from the first end surface along a direction from the second metal portion toward the first metal portion. The second insulator portion can block burrs on the first end surface, reducing the possibility of burrs piercing the separator and contacting the second pole piece, thereby reducing the risk of short circuits.

[0044] In some embodiments, the second insulator portion protrudes from the second connector portion in the second direction. The second insulator portion can block burrs at both ends of the second connector portion along the second direction, reducing the possibility of burrs piercing the isolation member and contacting the second pole piece, thereby reducing the risk of short circuit.

[0045] In some embodiments, the first insulating component further includes a first insulator portion and a third insulator portion, and the first insulator portion and the third insulator portion are connected to the second insulator portion; in the first direction, the first insulator portion and the third insulator portion are both located on the side of the second insulator portion facing away from the active material layer. The first insulator portion covers the surface of the first connector portion facing away from the protrusion. The first insulator portion and the third insulator portion are arranged and connected along the second direction. The third insulator portion can block burrs on the end face of the second connector portion away from the active material layer, and can also block burrs on the end of the first connector portion along the second direction, thereby reducing the possibility of burrs piercing the isolating member and contacting the second pole piece, reducing the risk of short circuit, and improving the reliability of the battery cell.

[0046] In some embodiments, the second connector portion is welded to the surface of the transition portion facing away from the insulating substrate to form a second weld print portion, and the first weld print includes the second weld print portion. The second insulator portion covers at least a portion of the second weld print portion. The second weld print portion can be directly used for current flow between the second connector portion and the transition portion, which is beneficial for improving the current flow capacity between the second connector portion and the transition portion and reducing the heat generation of the battery cell. The second insulator portion can block burrs, metal debris, and other structures on the second weld print portion, reducing the risk of these structures passing through the isolation member and contacting the second pole piece, which is beneficial for improving the reliability of the battery cell.

[0047] In some embodiments, along the first direction, both ends of the second weld print do not extend beyond the second insulator portion, thereby reducing the exposed area of the second weld print, lowering the risk of the second weld print puncturing the isolation member, and improving the reliability of the battery cell.

[0048] In some embodiments, along the second direction, the dimension of the transition portion is L2, the dimension of the second weld portion is L3, and 0.8≤L3 / L2≤1. Setting L3 / L2 to 0.8-1 can make the dimension of the transition portion along the second direction larger, which is beneficial for increasing the connection area between the first connection portion and the transition portion, improving the flow capacity of the connection between the first connection portion and the transition portion, reducing the heat generation of the battery cell, and improving the fast charging performance of the battery cell.

[0049] In some embodiments, the end face of the second connector away from the active material layer is flush with the end face of the transition part away from the first metal part, which can reduce the redundancy of the second connector or the transition part, save materials, improve space utilization, and enhance the energy density of the battery cell.

[0050] In some embodiments, there are multiple protrusions, and the multiple protrusions are spaced apart along the second direction. The first connecting portion includes a second connecting sub-portion and multiple first connecting sub-portions. The multiple first connecting sub-portions are spaced apart along the second direction, and each first connecting sub-portion is welded to each protrusion one by one to form a first weld mark. The second connecting sub-portions are continuously arranged along the second direction and welded to the transition portion to form a second weld mark. The first weld mark includes the second weld mark and multiple first weld marks. The second connecting sub-portions are continuously arranged along the second direction, connecting the multiple first connecting sub-portions into a single entity. The second connecting sub-portions provide good support for the first connecting sub-portions, reducing the risk of the first connecting sub-portion being inserted between the active material layer and the second electrode sheet when bent, reducing the risk of short circuits, and improving the reliability of the battery cell. In addition, the large size of the second connecting sub-portion along the second direction increases the welding area between the second connecting sub-portion and the transition portion, improving the flow capacity at the connection between the first connecting portion and the transition portion, improving the flow capacity of the first electrode sheet, and improving the fast charging performance and reliability of the battery cell.

[0051] In some embodiments, the protrusion includes a first protruding sub-portion and a second protruding sub-portion, and the first protruding sub-portion is connected between the second protruding sub-portion and the 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 connecting sub-portion includes a first connecting protrusion and a second connecting protrusion, the first connecting protrusion is located on the side of the first protruding sub-portion facing away from the insulating base, and the second connecting protrusion is located on the side of the second protruding sub-portion facing away from the insulating base; along the second direction, the size of the first connecting protrusion is larger than the size of the second connecting protrusion. The first insulating component includes at least one first insulator portion, and the first insulator portion corresponds to the first connecting sub-portion one-to-one. The first insulator portion covers the first connecting protrusion and the second connecting protrusion. The first insulator portion can cover the first connecting protrusion and the second connecting protrusion, reducing the risk of the first connecting sub-portion contacting and conducting with the second pole piece.

[0052] In some embodiments, the second metal part includes a transition part, and in the second direction, the two ends of the transition part are flush with the two ends of the first metal part respectively, and the second direction is perpendicular to the first direction and the thickness direction of the current collector. The first connecting part includes a second connecting sub-part, and the second connecting sub-part is located on the side of the transition part facing away from the insulating substrate. The second connecting sub-part is welded to the surface of the transition part facing away from the insulating substrate and forms a second weld print part, and the first weld print includes the second weld print part. The end face of the second connecting sub-part facing the active material layer is the first end face. During the cycle of the battery cell, the current can be transmitted between the transition part and the second connecting sub-part, thereby improving the overcurrent capacity and improving the fast charging performance and reliability of the battery cell. The first insulating component can block the burrs at the first end face, reduce the possibility of the burrs piercing the isolating member and contacting the second pole piece, and thereby reduce the risk of short circuit.

[0053] In some embodiments, the first insulating member protrudes from the end surface of the second connector portion facing away from the active material layer, along the direction from the first metal portion to the second metal portion. The first insulating member can block burrs on the end surface of the second connector portion facing away from the active material layer, reducing the possibility of burrs piercing the separator and contacting the second electrode piece, thereby reducing the risk of short circuits.

[0054] In some embodiments, both ends of the first insulating component protrude from the second connecting sub-portion in the second direction. The first insulating component can block burrs at both ends of the second connecting sub-portion along the second direction, reducing the possibility of burrs piercing the isolation member and contacting the second pole piece, thereby reducing the risk of short circuit.

[0055] In some embodiments, the electrode assembly further includes a second electrode piece having a polarity opposite to that of the first electrode piece. The second electrode piece includes a main functional portion and a tab portion, with the tab portion extending from an end surface of the main functional portion along a first direction. Along the direction from the active material layer to the first connecting portion, the end surface of the second connecting sub-portion facing away from the active material layer extends beyond the main functional portion. Even if a burr on the end surface of the second connecting sub-portion facing away from the active material layer punctures the separator, the burr is unlikely to come into contact with the main functional portion, thereby reducing the risk of a short circuit.

[0056] In some embodiments, the electrode assembly further includes a second pole piece having a polarity opposite to that of the first pole piece, the second pole piece including a main functional portion and a pole ear portion, the pole ear portion extending from the end face of the main functional portion along the first direction. Along the direction of the active material layer pointing to the first connecting portion, the end face of the main functional portion toward the pole ear portion exceeds the first end face. The first insulating component separates the first end face from the main functional portion. The main functional portion can exceed the first end face, so that the main functional portion can have a larger size in the first direction, thereby increasing the capacity of the main functional portion. The first insulating component separates the first end face from the main functional portion, thereby blocking the burrs at the first end face, reducing the possibility of the burrs at the first end face overlapping with the main functional portion, reducing the risk of short circuit, and improving the reliability of the battery cell.

[0057] In some embodiments, the first insulating component extends beyond the end surface of the main functional portion toward the pole ear portion, along the direction from the active material layer toward the first connecting portion. The first insulating component can prevent burrs on the end surface of the main functional portion of the second pole piece near the pole ear portion from piercing the separator and connecting with the first pole piece, thereby reducing the risk of short circuit between the first and second pole pieces and improving the reliability of the battery cell.

[0058] In some embodiments, the current collector includes two metal layers, and the two metal layers are provided on opposite sides of the insulating substrate along the thickness direction of the current collector. The first pole piece includes two active material layers and two conductive members, the two active material layers are respectively provided on the two metal layers, and the first connection parts of the two conductive members are respectively connected to the two metal layers. The electrode assembly includes two first insulating parts, and the two first insulating parts are respectively attached to the first connection parts of the two conductive members. The two conductive members can respectively draw out the current of the two metal layers, thereby improving the overcurrent capacity and improving the fast charging performance of the battery cell. The two first insulating parts can respectively cover the burrs at the first end faces of the two first connecting parts, thereby reducing the possibility of the burrs piercing the isolating part and contacting the second pole piece, thereby reducing the risk of short circuit.

[0059] In some embodiments, a portion of the two first insulating components is affixed and / or connected to reduce the risk of burrs extending from between the two first insulating components and improve reliability.

[0060] In some embodiments, the conductive member further includes a second connecting portion connected to the first connecting portion. In the first direction, the second connecting portion is located on the side of the first connecting portion facing away from the active material layer. The second connecting portion is electrically connected to the electrode lead portion. The second connecting portions of the two conductive members are welded to form a second weld mark. The second connecting portions of the two conductive members can 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 electrode sheet, enhancing the fast charging performance of the battery cell, reducing the heat generation of the battery cell, and improving the reliability of the battery cell.

[0061] In some embodiments, the first insulating member covers at least a portion of the second weld print. The first insulating member can block burrs, metal debris, and other components on the second weld print, reducing the risk of burrs, metal debris, and other components piercing the separator and contacting the second electrode sheet, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0062] In some embodiments, the first insulating member protrudes from the edge of the second weld mark away from the active material layer, along the direction from the active material layer toward the first connecting portion. The first insulating member can completely cover the second weld mark to block burrs, metal debris, and other components on the entire second weld mark, reducing the risk of burrs, metal debris, and other components piercing the separator and contacting the second electrode sheet, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0063] In some embodiments, the metal layer includes a first metal portion and a second metal portion arranged and connected along a first direction. The first metal portion is covered with an active material layer, while the second metal portion is not covered with the active material layer. The second metal portion includes a transition portion and at least one protrusion; the transition portion connects between the first metal portion and the protrusion. Along a second direction, the transition portion has a dimension greater than the sum of the dimensions of all protrusions. The second direction is perpendicular to the first direction and the thickness of the current collector. The first connecting portion is welded to the second metal portion to form a first weld mark.

[0064] In some embodiments, along the second direction, the dimension of the first metal portion is L1, the dimension of the transition portion is L2, and 0.8 ≤ L2 / L1 ≤ 1. Setting L2 / L1 to 0.8-1 allows the transition portion to have a larger dimension along the second direction, which helps increase the connection area between the second connecting sub-portion and the transition portion, improve the flow capacity of the connection between the second connecting sub-portion and the transition portion, improve the flow capacity of the first electrode, reduce heat generation of the battery cell, and improve the fast charging performance of the battery cell.

[0065] In some embodiments, at least a portion of the first metal portion is thinner than the transition portion. A thicker transition portion provides better current-carrying capacity, thereby improving the current-carrying capacity of the first electrode sheet, reducing heat generation in the battery cell, and improving the fast-charging performance and reliability of the battery cell.

[0066] In some embodiments, the first metal portion includes a first sub-portion and a second sub-portion, the first sub-portion being connected between the second sub-portion and the transition portion, the first sub-portion and the second sub-portion being covered with an active material layer, the thickness of the first sub-portion being greater than the thickness of the second sub-portion, and the thickness of the transition portion being greater than or equal to the thickness of the first sub-portion. The first sub-portion being connected between the second sub-portion and the transition portion, and the thickness of the first sub-portion being greater than the thickness of the second sub-portion, ensures that the flow capacity of the first sub-portion closer to the transition portion is greater than that of the second sub-portion farther from the transition portion. This reduces current restrictions, improves the flow capacity of the first electrode, reduces heat generation in the battery cell, and facilitates improved reliability of the battery cell.

[0067] In some embodiments, the current collector further includes a conductive protective layer comprising a first protective portion and a second protective portion. The first protective portion is positioned between the first sub-portion and the active material layer, and the second protective portion is positioned between the second sub-portion and the active material layer. The thickness of the first protective portion is less than that of the second protective portion. By providing first and second protective portions of different thicknesses, the surface of the conductive protective layer facing away from the insulating substrate can be made nearly planar, thereby minimizing rolling damage and improving the current carrying capacity of the metal layer. Furthermore, this can reduce the risk of bulging during winding of the current collector.

[0068] In some embodiments, the conductive protective layer further includes a third protective portion, which covers the surface of the transition portion facing away from the insulating substrate. The thickness of the third protective portion is less than or equal to the thickness of the first protective portion. The provision of the third protective portion allows the conductive protective layer to protrude beyond the active material layer, effectively separating the active material layer from the metal layer. Furthermore, the thickness of the third protective portion is not excessive, thereby reducing material waste and lowering the production cost of the battery cell.

[0069] In some embodiments, the thickness of the protrusion is greater than or equal to the thickness of the transition portion. A thicker protrusion can improve the current carrying capacity of the protrusion, which is beneficial for improving the current carrying capacity of the first electrode sheet, reducing heat generation of the battery cell, and improving the fast charging performance and reliability of the battery cell.

[0070] In some embodiments, the conductive member further includes at least one second connecting portion connected to the first connecting portion. In the first direction, the second connecting portion is located on a side of the first connecting portion facing away from the active material layer. The second connecting portion is electrically connected to the electrode lead portion. The second connecting portion protrudes from the metal layer, facilitating connection between the second connecting portion and the electrode lead portion and facilitating fabrication. This also reduces the risk of problems such as cold solder joints, improving the reliability of the connection between the metal layer and the conductive member, and enhancing the current carrying capacity of the first electrode sheet, thereby improving the fast-charging performance of the battery cell.

[0071] In some embodiments, the first connecting portion includes a plurality of first connecting sub-portions, and the plurality of first connecting sub-portions are spaced apart along a second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector. Each first connecting sub-portion is connected to the metal layer. There are multiple second connecting portions, and each first connecting sub-portion is connected to each second connecting portion in a one-to-one correspondence. By providing multiple second connecting portions, the flow area can be increased, the flow capacity of the conductive component can be improved, the fast charging performance of the battery cell can be improved, the heat generation of the battery cell can be reduced, and the reliability of the battery cell can be improved.

[0072] In some embodiments, the first connection portion is welded to a surface of the metal layer facing away from the insulating substrate to form a first weld mark. Along the first direction, a distance S1 between the first weld mark and the active material layer is defined as follows: 0.3 mm ≤ S1 ≤ 5 mm, and optionally, 0.5 mm ≤ S1 ≤ 2.8 mm.

[0073] The first weld mark can transmit current between the first connection portion and the metal layer, thereby improving current flow capacity and reducing heat generation. Setting S1 to greater than or equal to 0.3mm allows for a gap between the first weld mark and the active material layer, reducing the risk of the conductive component welding to the active material layer and reducing problems such as cold solder joints, thereby improving the connection reliability between the first connection portion and the metal layer. Setting S1 to less than or equal to 5mm prevents excessive spacing between the first weld mark and the active material layer. Given a constant dimension of the metal layer along the first direction, the active material layer can cover a larger area, thereby increasing the coverage area of the active material layer on the metal layer and improving the energy density of the battery cell.

[0074] In some embodiments, the current collector further includes a conductive protective layer, at least a portion of which is located between the active material layer and the metal layer. The conductive protective layer can separate the active material layer from the metal layer and protect the metal layer, thereby reducing the risk of cracks in the metal layer caused by rolling the active material layer, thereby improving the current carrying capacity of the metal layer.

[0075] In some embodiments, the conductive protective layer protrudes from the end surface of the active material layer facing the first connecting portion, along the direction from the active material layer to the first connecting portion. The conductive protective layer protrudes from the active material layer, which can completely separate the metal layer from the active material layer. Furthermore, it can provide expansion space during the rolling process of the active material layer, which helps the subsequent conductive protective layer completely separate the metal layer from the active material layer.

[0076] In some embodiments, the conductive protective layer protrudes from the end surface of the active material layer facing the first connecting portion by a length ranging from 0.3 mm to 0.8 mm, along the direction from the active material layer to the first connecting portion. The conductive protective layer can completely separate the active material layer from the metal layer, providing excellent protection for the metal layer and improving the current carrying capacity of the first electrode sheet, thereby improving the fast charging performance and reliability of the battery cell. The conductive protective layer does not protrude too far, which helps save internal space in the battery cell and improve the energy density of the battery cell.

[0077] In some embodiments, the conductive protective layer and the first connecting portion are spaced apart along the first direction to reduce the possibility of overlap between the first connecting portion and the conductive protective layer, reduce the conductive protective layer from interfering with the connection between the first connecting portion and the metal layer, and improve the connection strength and current carrying capacity between the first connecting portion and the metal layer.

[0078] In some embodiments, the first insulating component includes an insulating base layer and an adhesive layer, with at least a portion of the adhesive layer bonded between the insulating base layer and the first connecting portion. The insulating base layer may have high structural strength, blocking burrs and preventing them from puncturing, thereby improving insulation. Compared to the adhesive layer, the insulating base layer has greater strength, resulting in less deformation during the bonding process of the first insulating component. The adhesive layer can stably secure the insulating base layer to the first pole piece, reducing the risk of the first insulating portion falling off.

[0079] In some embodiments, the thickness of the insulating base layer ranges from 6μm to 15μm; and / or the thickness of the adhesive layer ranges from 0.5μm to 3μm. The insulating base layer has a certain thickness, and the insulating base layer can block burrs and achieve insulation; the thickness of the insulating base layer is less than or equal to 15μm, so that the thickness of the insulating base layer is not too large, which is beneficial to reducing the volume occupied by the first insulating component and improving the energy density of the battery cell. The adhesive layer has a certain thickness, so that the first insulating component can be stably bonded to the first pole piece, improving the insulation reliability of the first insulating component; the thickness of the adhesive layer is less than or equal to 3μm, so that the thickness of the adhesive layer is not too large, which is beneficial to reducing the volume occupied by the first insulating component and improving the energy density of the battery cell.

[0080] In some embodiments, the first insulating component has a dimension W along the first direction, 3 mm ≤ W ≤ 9 mm, and optionally, 4.5 mm ≤ W ≤ 6.5 mm. Limiting W to greater than or equal to 3 mm allows the first insulating component to have a certain size, effectively blocking burrs on the first end surface and improving the internal insulation of the battery cell. Limiting W to less than or equal to 9 mm limits the dimension of the first insulating component along the first direction, which helps reduce the volume and weight occupied by the first insulating component and improve the energy density of the battery cell.

[0081] In a second aspect, an embodiment of the present application provides a battery device, which includes a battery cell provided by any embodiment of the first aspect.

[0082] In a third aspect, an embodiment of the present application provides an electrical device, including a battery device provided by any embodiment of the second aspect, the battery device being used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. 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 the drawings without creative work.

[0084] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0085] Figure 2 Schematic diagram of a battery device provided in some embodiments of the present application;

[0086] Figure 3 An exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0087] Figure 4 A schematic diagram of an electrode assembly of a battery cell provided in some embodiments of the present application;

[0088] Figure 5 for Figure 4 A schematic cross-sectional view of the electrode assembly shown along line AA;

[0089] Figure 6 for Figure 5 Enlarged schematic diagram at the box;

[0090] Figure 7 A schematic diagram of a first pole piece and a first insulating component of a battery cell in an unfolded state provided by some embodiments of the present application;

[0091] Figure 8 for Figure 7 A schematic cross-sectional view taken along line BB;

[0092] Figure 9 for Figure 7 Schematic cross-section made along Line CC;

[0093] Figure 10 for Figure 7 A schematic diagram of the first pole piece shown;

[0094] Figure 11 for Figure 10An enlarged schematic diagram at the circle;

[0095] Figure 12 for Figure 10 Another schematic diagram of the first pole piece shown, wherein the conductive member is shown;

[0096] Figure 13 for Figure 12 An enlarged schematic diagram at the circle;

[0097] Figure 14 for Figure 7 A schematic diagram of the first insulating component shown;

[0098] Figure 15 for Figure 14 An enlarged schematic diagram at the circle;

[0099] Figure 16 for Figure 10 A schematic diagram of the conductive member shown;

[0100] Figure 17 for Figure 16 An enlarged schematic diagram at the circle;

[0101] Figure 18 A partial cross-sectional schematic diagram of an electrode assembly of a battery cell provided in some other embodiments of the present application;

[0102] Figure 19 Schematic diagram of a first pole piece, a first insulating component, and a second insulating component of a battery cell in an unfolded state provided by some other embodiments of the present application;

[0103] Figure 20 for Figure 19 Schematic cross-section along line DD;

[0104] Figure 21 for Figure 19 A schematic diagram of the first pole piece and the second insulating component shown;

[0105] Figure 22 for Figure 21 An enlarged schematic diagram at the circle;

[0106] Figure 23 for Figure 21 A schematic diagram of a first pole piece is shown, wherein the conductive member is shown;

[0107] Figure 24 for Figure 23 An enlarged schematic diagram at the circle;

[0108] Figure 25 for Figure 19 A schematic diagram of the first insulating component shown;

[0109] Figure 26 for Figure 25 An enlarged schematic diagram at the circle;

[0110] Figure 27 for Figure 21 A schematic diagram of a portion of a conductive member is shown;

[0111] Figure 28 Schematic diagram of a first pole piece, a first insulating component, and a second insulating component of a battery cell in an unfolded state provided by some other embodiments of the present application;

[0112] Figure 29 for Figure 28 A schematic diagram of a partial structure of the first insulating component shown;

[0113] Figure 30 Schematic diagram of a first pole piece and a first insulating component of a battery cell in an unfolded state provided by some other embodiments of the present application;

[0114] Figure 31 for Figure 30 A schematic diagram of the first pole piece shown;

[0115] Figure 32 for Figure 31 Another schematic diagram of the first pole piece shown, wherein the conductive member is omitted;

[0116] Figure 33 A partial cross-sectional schematic diagram of an electrode assembly of a battery cell provided in some other embodiments of the present application;

[0117] Figure 34 A partial cross-sectional schematic diagram of an electrode assembly of a battery cell provided in some other embodiments of the present application;

[0118] Figure 35 Schematic diagram of a first pole piece of a battery cell in a flattened state provided in some other embodiments of the present application, wherein the conductive member is omitted;

[0119] Figure 36 for Figure 35 Enlarged view of the circled part;

[0120] Figure 37 A schematic diagram of a first insulating component of a battery cell provided in some embodiments of the present application;

[0121] Figure 38 Schematic partial cross-sectional views of electrode assemblies of battery cells provided in some other embodiments of the present application.

[0122] In the drawings, the drawings are not drawn to scale.

[0123] The following are the descriptions of the reference numerals:

[0124] 1000, vehicle; 1100, battery device; 1200, controller; 1300, motor;

[0125] 100, battery cell; 101, electrode assembly; 200, housing; 201, end cap; 2011, electrode lead portion; 202, housing; 300, housing; 301, first housing portion; 302, second housing portion;

[0126] 1. The first pole piece;

[0127] 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. Protruding portion; 1221a. First protruding sub-portion; 1221b. Second protruding sub-portion; 1222. Transition portion; 13. Conductive protective layer; 131. First protective portion; 132. Second protective portion; 133. Third protective portion;

[0128] 20. Active material layer; 21. First active material portion; 22. Second active material portion;

[0129] 30. Conductive member; 31. First connecting portion; 311. First connecting sub-portion; 3111. First connecting protrusion; 3112. Second connecting protrusion; 312. Second connecting sub-portion; 31a. First end surface; 31b. Second end surface; 32. Second connecting portion;

[0130] 2. Second pole piece; 210. Main functional part; 220. Ear part;

[0131] 3. Isolation parts;

[0132] 4. First insulating component; 40. Insulating sheet; 41. First insulator portion; 42. Second insulator portion; 43. Third insulator portion; 44. Fourth insulator portion; 4a. Insulating base layer; 4b. Adhesive layer; 4c. Through hole;

[0133] 51, first weld print; 511, first weld print portion; 5111, first weld print sub-portion; 5112, second weld print sub-portion; 512, second weld print portion; 52, second weld print;

[0134] 6. A second insulating component;

[0135] X, second direction; Y, thickness direction; Z, first direction. DETAILED DESCRIPTION

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] The term "plurality" used in this application refers to two or more (including two).

[0145] Currently, market developments indicate that battery applications are becoming increasingly widespread. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. As battery applications continue to expand, market demand is also growing.

[0146] A battery device generally refers to a single physical module that includes multiple battery cells to provide higher voltage and capacity. A battery cell may be the smallest unit that makes up a battery device.

[0147] A battery cell generally includes a housing and an electrode assembly housed in the housing. The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, and a separator separating the positive electrode sheet from the negative electrode sheet.

[0148] 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. 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.

[0149] 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.

[0150] In order to reduce the risk of short circuit in battery cells, a current collector is proposed. The current collector includes an insulating substrate and a metal layer covering the surface of the insulating substrate. The active material layer covers the surface of the metal layer facing away from the insulating substrate. The thickness of the metal layer is usually set to be small, so that when foreign objects pierce the pole piece, the burrs generated on the metal layer are small and it is not easy to pierce the isolation piece.

[0151] To draw current from the metal layer, the pole piece is typically equipped with a conductive member connected to the metal layer. However, the conductive member must be cut into a predetermined shape to meet design requirements. However, burrs are prone to forming on the cut end surface of the conductive member, which can easily pierce the separator, causing a short circuit risk and affecting the reliability of the battery cell.

[0152] In view of this, an embodiment of the present application provides a technical solution, which provides an insulating component to cover the end face of the conductive component facing the active material layer, thereby reducing the risk of burrs on the end face piercing the isolation member, which is beneficial to improving the reliability of the battery cell.

[0153] The battery cells described in the embodiments of the present application are applicable to battery devices and electrical devices using the battery devices.

[0154] 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 can 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 can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and the spacecraft can include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0155] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0156] Figure 1 A schematic structural diagram of a vehicle provided for some embodiments of the present application.

[0157] 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.

[0158] The vehicle 1000 may further include a controller 1200 and a motor 1300 . The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0159] 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.

[0160] Figure 2 Schematic diagram of a battery device provided in some embodiments of the present application.

[0161] In some embodiments, the battery device 1100 may include one or more battery cell assemblies to provide voltage and capacity.

[0162] The battery cell assembly may include a plurality of battery cells 100. The plurality of battery cells 100 may be connected in series, in parallel, or in parallel via a busbar. Parallel connection means that the plurality of battery cells 100 are connected in both series and parallel.

[0163] The battery cell 100 may be a secondary battery cell, which refers to a battery cell that can be recharged to activate the active material after discharge and continue to be used. For example, a battery cell may be the smallest unit constituting a battery device.

[0164] As an example, the battery cell 100 can be a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead storage battery cell, etc.

[0165] As an example, the battery cell 100 may be a prismatic battery cell, a soft-pack battery cell, or a battery cell of another shape. 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.

[0166] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 100. For example, the battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 100 to form an independent module. For example, a battery module can be formed by bundling multiple battery cells 100 using cable ties.

[0167] In some embodiments, the battery device 1100 may be a battery pack, which includes a housing 300 and one or more battery cell assemblies housed in the housing 300. For example, the battery cell assembly may be a battery module, which may be housed in the housing 300 by securing the battery module in the housing 300. For example, the battery cell assembly may also be housed in the housing 300 by directly securing multiple battery cells 100 to the housing 300.

[0168] In some embodiments, the box 300 is used to accommodate the battery cells 100 , and the box 300 can have various structures.

[0169] In some embodiments, the housing 300 may include a first housing portion 301 and a second housing portion 302. The first housing portion 301 and the second housing portion 302 engage to form an enclosed space within the housing 300 for accommodating the battery cell assembly. Enclosed here means covered or closed, and can be either sealed or unsealed. The first housing portion 301 may be a top cover or a bottom plate.

[0170] In some embodiments, the housing 300 may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame to form an enclosed space within the housing 300 to accommodate the battery cell assembly. As an example, the frame may include multiple side beams.

[0171] In some embodiments, the box 300 may serve as part of the chassis structure of the vehicle 1000. For example, a portion of the box 300 may become at least a portion of the floor of the vehicle 1000, or a portion of the box 300 may become at least a portion of the cross member and longitudinal member of the vehicle 1000.

[0172] In some embodiments, the battery device 1100 may be an energy storage device.

[0173] Energy storage devices can be used in energy storage power stations, wind power systems, solar power systems, mobile power systems, or temporary power supply systems. They can store electrical energy as needed and deliver it when appropriate. For example, they can store energy during low-demand periods and provide it to users or devices during peak demand periods.

[0174] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0175] Figure 3 Schematic diagram of an explosion of a battery cell provided in some embodiments of the present application.

[0176] Reference Figure 3 In some embodiments, the battery cell 100 includes a housing 200 and an electrode assembly 101 accommodated in the housing 200 .

[0177] In some embodiments, the housing 200 may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite housing 200 ), or an aluminum-plastic film.

[0178] In some embodiments, the housing 200 can be a sealed structure or a non-sealed structure. For example, when the housing 200 is a non-sealed structure, the housing 200 protects the electrode assembly 101. A sealing bag is also included between the housing 200 and the electrode assembly 101. The sealing bag is used to encapsulate the electrode assembly 101 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film. When the housing 200 is a sealed structure, it is used to encapsulate the electrode assembly 101, the electrolyte, and other components.

[0179] In some embodiments, the housing 200 includes a shell 202 and an end cap 201 , wherein the shell 202 has an opening, and the end cap 201 is connected to the shell 202 and covers the opening;

[0180] The housing 202 is a component used to cooperate with the end cap 201 to form an internal cavity of the battery cell 100. The formed internal cavity can be used to accommodate the electrode assembly 101, electrolyte and other components.

[0181] 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 100 .

[0182] 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.

[0183] 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 100 with higher structural strength and improved reliability.

[0184] The end cover 201 is connected to the housing 202 by welding, bonding, clamping or other methods.

[0185] 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.

[0186] The electrode assembly 101 is a component where electrochemical reactions occur in the battery cell 100. One or more electrode assemblies 101 may be contained in the housing 202.

[0187] The electrode assembly 101 includes a first electrode piece, a second electrode piece, and an isolating member. The first electrode piece and the second electrode piece have opposite polarities, and the isolating member separates the first electrode piece from the second electrode piece.

[0188] One of the first and second electrode sheets is a positive electrode sheet, and the other is a negative electrode sheet. At least a portion of the separator is located between the positive and negative electrode sheets. During the charge and discharge process of the battery cell 100, active ions (e.g., lithium ions) are intercalated and released between the positive and negative electrode sheets. The separator is positioned between the positive and negative electrode sheets to prevent short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0189] In some embodiments, the battery cell 100 includes two electrode lead-out portions 2011 . For example, the two electrode lead-out portions 2011 are electrically connected to the positive electrode sheet and the negative electrode sheet, respectively, for outputting or inputting electrical energy from the battery cell 100 .

[0190] Illustratively, at least one electrode lead-out portion 2011 is a positive electrode lead-out portion, and at least one electrode lead-out portion 2011 is a negative electrode lead-out portion. The positive electrode lead-out portion is connected to the positive electrode sheet, and the negative electrode lead-out portion is connected to the positive electrode sheet.

[0191] The positive electrode lead portion and the negative electrode lead portion are used to be electrically connected to an external circuit to enable charging or discharging of the battery cell 100 .

[0192] In some embodiments, the positive electrode lead-out portion includes a positive electrode terminal. At least a portion of the positive electrode terminal is exposed to the outside of the battery cell 100 to facilitate connection with a busbar component.

[0193] As an example, the positive terminal may be an independently formed component, which is mounted on the housing 202 or the end cap 201. Alternatively, the positive terminal may also be a part of the housing 202 or a part of the end cap 201.

[0194] In some examples, the positive terminal is directly connected to the positive electrode sheet; in other examples, the positive electrode lead-out portion further includes other conductive structures connecting the positive terminal and the positive electrode sheet, such as a positive electrode adapter sheet.

[0195] In some embodiments, the positive terminal is connected to the end cap 201 by welding, riveting, clamping or other means.

[0196] In some embodiments, the negative electrode lead-out portion includes a negative electrode terminal, at least a portion of which is exposed to the outside of the battery cell 100 to facilitate connection with a busbar component.

[0197] As an example, the negative terminal may be an independently formed component, which is mounted on the housing 202 or the end cap 201. Alternatively, the negative terminal may also be a part of the housing 202 or a part of the end cap 201.

[0198] In some examples, the negative terminal is directly connected to the negative electrode sheet; in other examples, the negative electrode lead-out portion further includes other conductive structures connecting the negative terminal and the negative electrode sheet, such as a negative electrode adapter sheet.

[0199] In some embodiments, the negative terminal is connected to the end cap 201 by welding, riveting, clamping or other means.

[0200] In some embodiments, the battery cell 100 further includes an electrolyte contained within the housing 200. The electrolyte conducts ions between the positive and negative electrodes and can be in liquid, gel, or solid form.

[0201] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] In some embodiments, the gel electrolyte includes a polymer as an electrolyte skeleton network and an ionic liquid-lithium salt.

[0206] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, or a composite solid electrolyte.

[0207] 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.

[0208] 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.

[0209] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0210] Figure 4 Schematic diagram of an electrode assembly of a battery cell provided in some embodiments of the present application.

[0211] Reference Figure 4 The electrode assembly 101 includes a first electrode sheet 1 and a second electrode sheet 2 with opposite polarities. For example, 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.

[0212] 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.

[0213] 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.

[0214] 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.).

[0215] 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. These positive electrode active materials can 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 iron manganese phosphate, and a composite material of lithium iron manganese 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 / 3Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (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.

[0216] 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.

[0217] 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.).

[0218] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may adopt the negative electrode active material for battery cells 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 for battery devices. These negative electrode active materials may be used alone or in combination of two or more.

[0219] In some embodiments, the positive electrode current collector is a composite current collector and the negative electrode current collector is copper foil; in other embodiments, the positive electrode current collector is aluminum foil and the negative electrode current collector is a composite current collector; in still other embodiments, both the positive electrode current collector and the negative electrode current collector are composite current collectors.

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] In some embodiments, the electrode assembly 101 is a laminated structure.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] 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 .

[0230] 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.

[0231] In some embodiments, the shape of the electrode assembly 101 can be cylindrical, flat, or polygonal.

[0232] Figure 5 for Figure 4 A schematic cross-sectional view of the electrode assembly shown along line AA; Figure 6 for Figure 5 Enlarged schematic diagram at the box; Figure 7 A schematic diagram of a first pole piece and a first insulating component of a battery cell in an unfolded state provided by some embodiments of the present application; Figure 8 for Figure 7 A schematic cross-sectional view taken along line BB; Figure 9 for Figure 7 Schematic cross-section made along Line CC; Figure 10 for Figure 7 A schematic diagram of the first pole piece shown; Figure 11 for Figure 10 An enlarged schematic diagram at the circle; Figure 12 for Figure 10 Another schematic diagram of the first pole piece shown, wherein the conductive member is shown; Figure 13 for Figure 12 An enlarged schematic diagram at the circle; Figure 14 for Figure 7 A schematic diagram of the first insulating component shown; Figure 15 for Figure 14 An enlarged schematic diagram at the circle; Figure 16 for Figure 10 A schematic diagram of the conductive member shown; Figure 17 for Figure 16 Enlarged diagram of the circle.

[0233] Reference Figures 3 to 17 , an embodiment of the present application provides a battery cell 100, which includes a shell 200 and an electrode assembly 101. The shell 200 is provided with an electrode lead-out portion 2011. At least a portion of the electrode assembly 101 is accommodated in the shell 200. The electrode assembly 101 includes a first pole piece 1 and a first insulating component 4. The first pole piece 1 includes a conductive component 30, a current collector 10 and an active material layer 20. The current collector 10 includes an insulating base 11 and a metal layer 12. The insulating base 11, the metal layer 12 and the active material layer 20 are stacked along the thickness direction Y of the current collector. At least a portion of the metal layer 12 is located between the insulating base 11 and the active material layer 20. The conductive component 30 is used to electrically connect the metal layer 12 and the electrode lead-out portion 2011. The conductive member 30 includes a first connecting portion 31, which is located on the side of the metal layer 12 facing away from the insulating substrate 11 and connected to the metal layer 12. The active material layer 20 and the first connecting portion 31 are arranged along a first direction Z, which is perpendicular to the thickness direction Y of the current collector. At least a portion of the first insulating component 4 is located on the side of the first connecting portion 31 facing away from the metal layer 12 and attached to the first connecting portion 31. Along the direction from the first connecting portion 31 to the active material layer 20, the first insulating component 4 protrudes from the first connecting portion 31 and has a first end surface 31a facing the active material layer 20.

[0234] In some examples, a portion of the electrode assembly 101 is located within the housing 200 , and another portion is located outside the housing 200 . Alternatively, the entire electrode assembly 101 is located within the housing 200 .

[0235] The first electrode sheet 1 can be a positive electrode sheet or a negative electrode sheet. 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. In other examples, 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 adopts a composite current collector structure, and the active material layer 20 is a negative electrode active material layer.

[0236] The conductive member 30 may be a component used to connect the electrode lead portion 2011 and the current collector 10. As an example, the material of the conductive member 30 may be the same as that of the metal layer 12. As an example, the conductive member 30 may be made of copper foil or aluminum foil to facilitate connection with the electrode lead portion 2011.

[0237] The electrode lead portion 2011 can be directly connected to the conductive member 30; for example, the electrode lead portion 2011 can be directly welded to the conductive member 30. Alternatively, the electrode lead portion 2011 can be connected to the conductive member 30 through a conductive member (such as an adapter, etc.), for example, one end of the conductive member is welded to the conductive member 30, and the other end of the conductive member is welded to the electrode lead portion 2011.

[0238] The current collector 10 includes a metal layer 12 and an insulating base 11. The current collector 10 is a multi-layer structure. The insulating base 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 metal material.

[0239] 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. 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 can be the thickness direction Y of the current collector (see Figure 8 Y direction in ).

[0240] The active material layer 20 may be directly coated on the surface of the metal layer 12 , or the surface of the metal layer 12 may be coated with other materials and then coated with the active material layer 20 .

[0241] In some examples, one surface of the insulating substrate 11 is covered with a metal layer 12. In other examples, two opposite surfaces of the insulating substrate 11 are covered with metal layers 12, and at least one of the two metal layers 12 is covered with an active material layer 20 on a surface facing away from the insulating substrate.

[0242] The first direction Z may refer to a direction perpendicular to the thickness direction Y of the current collector; the second direction X may refer to a direction perpendicular to both the thickness direction Y and the first direction Z of the current collector.

[0243] In some examples, the electrode assembly 101 has a wound structure. When the first electrode sheet 1 is in an unfolded state, the first direction Z can refer to the width direction of the first electrode sheet 1; the second direction X can refer to the length direction of the first electrode sheet 1. When the first electrode sheet 1 is in a wound state, the second direction X can also refer to the winding direction of the first electrode sheet 1.

[0244] In other examples, the electrode assembly 101 is a laminated structure, one of the first direction Z and the second direction X is the width direction of the first electrode sheet 1 , and the other is the length direction of the first electrode sheet 1 .

[0245] As an example, the active material layer 20 may cover a portion of the metal layer 12. The conductive member 30 may be connected to a portion of the metal layer 12 that is not covered by the active material layer 20.

[0246] The first connection portion 31 may be a portion of the conductive member 30 that overlaps the metal layer 12 in the thickness direction Y. The first connection portion 31 may be connected to the metal layer 12 by welding, bonding, or other methods to achieve electrical connection between the first connection portion 31 and the metal layer 12 .

[0247] In the first direction Z, the first end surface 31 a of the first connecting portion 31 may directly contact the active material layer 20 or may be spaced apart from the active material layer 20 .

[0248] The first connecting portion 31 may be a continuous integral body; correspondingly, the first end surface 31a is continuously provided. Alternatively, the first connecting portion 31 may also include multiple separately provided parts; correspondingly, the first end surface 31a may also include multiple separately arranged surfaces.

[0249] The first insulating component 4 may be an insulating component, an integrated structure, or a component in which multiple parts are formed separately and then assembled together.

[0250] The first insulating component 4 may be, but is not limited to, an insulating coating, an insulating adhesive (eg, hot melt adhesive, etc.), or an insulating tape.

[0251] There may be one or more first insulating members 4 .

[0252] The first insulating component 4 may be attached only to the first connecting portion 31 or to other parts of the first electrode piece 1. For example, the first insulating component 4 may also be attached to the active material layer 20, the metal layer 12 or other parts of the first electrode piece 1.

[0253] As an example, “attach” may refer to attaching and connecting. For example, the first insulating component 4 is attached to the first connecting portion 31 by bonding or coating.

[0254] The first insulating member 4 may have a structure that allows ions to pass through. For example, the first insulating member 4 may have a microporous structure. Alternatively, the first insulating member 4 may also have a structure that blocks ions from passing through.

[0255] For example, the direction in which the first connection portion 31 points toward the active material layer 20 may be parallel to the first direction Z.

[0256] Along the direction from the active material layer 20 to the first connecting portion 31 , the first insulating component 4 may or may not protrude from the end surface of the first connecting portion 31 facing away from the active material layer 20 .

[0257] The first insulating component 4 covers at least a portion of the first end surface 31 a in the thickness direction Y of the current collector. In the thickness direction Y of the current collector, the first insulating component 4 may completely cover the first end surface 31 a or only cover a portion of the first end surface 31 a.

[0258] In the thickness direction Y of the current collector, the projection of the first end face 31 a at least partially overlaps with the projection of the first insulating member 4 .

[0259] In the embodiment of the present application, the current collector 10 adopts a composite structure of an insulating substrate 11 and a metal layer 12. Compared with the current collector 10 made of pure metal, the thickness of the metal layer 12 is small. When the current collector 10 is accidentally punctured (for example, a nail penetration test), the burrs generated by the metal layer 12 are small, and the burrs of the metal layer 12 are not easy to pierce other components, thereby reducing the risk of short circuits and helping to improve the reliability of the battery cell 100. During the normal use of the battery cell 100, the first insulating component 4 can block the burrs at the first end face 31a, reduce the possibility of the burrs at the first end face 31a piercing other components, reduce the risk of short circuits, and improve the reliability of the battery cell 100. For example, the first insulating component 4 can block the burrs at the first end face 31a, reduce the possibility of the burrs piercing the separator 3 and contacting the second pole piece 2, thereby reducing the risk of short circuits.

[0260] In some embodiments, the first insulating component 4 completely covers the first end surface 31 a .

[0261] In some embodiments, along the first direction Z, the first connection portion 31 and the active material layer 20 are spaced apart.

[0262] The first connection portion 31 is not in direct contact with the active material layer 20, but there is a certain gap between them, so that the first connection portion 31 does not contact the active material layer 20. Other structures may or may not be provided in this gap.

[0263] Spacing the first connection portion 31 from the active material layer 20 can reduce the interaction between them and improve the reliability of the battery cell 100. For example, spacing the first connection portion 31 from the active material layer 20 can reduce the risk of interference between the first connection portion 31 and the active material layer 20 due to assembly errors. When the conductive member 30 is connected to other components (such as the electrode lead portion 2011), the stress transmitted to the active material layer 20 through the first connection portion 31 can be reduced, reducing the risk of active material from the active material layer 20 falling off.

[0264] In some embodiments, the battery cell 100 is a lithium-ion battery cell. The first connecting portion 31 does not contact the active material layer 20 , which can reduce risks such as lithium plating and improve the reliability of the battery cell 100 .

[0265] In some embodiments, the first insulating member 4 at least partially covers a region of the metal layer 12 between the first connecting portion 31 and the active material layer 20 .

[0266] The region of the metal layer 12 between the first connection portion 31 and the active material layer 20 may be referred to as an intermediate region. The first insulating member 4 may completely cover the intermediate region or may cover only a portion of the intermediate region.

[0267] The portion of the first insulating member 4 covering the middle region may be attached to the middle region or may be spaced apart from the middle region.

[0268] The first insulating component 4 can separate the area of the metal layer 12 not covered by the first connecting portion 31 and the active material layer 20 from the second electrode sheet 2 , thereby reducing the risk of short circuit and improving the reliability of the battery cell 100 .

[0269] In some embodiments, the first insulating member 4 completely covers the region of the metal layer 12 between the first connecting portion 31 and the active material layer 20 .

[0270] In some embodiments, along the first direction Z, a portion of the first insulating member 4 is located between the first connecting portion 31 and the active material layer 20 .

[0271] In some embodiments, a portion of the first insulating member 4 located between the first connecting portion 31 and the active material layer 20 is attached to the metal layer 12 .

[0272] Attaching the first insulating component 4 to the metal layer 12 can increase the connection strength between the first insulating component 4 and the first pole piece 1 and reduce the risk of the first insulating component 4 falling off. The portion of the first insulating component 4 attached to the metal layer 12 can shield the metal layer 12, improving insulation, reducing the risk of conduction between the metal layer 12 and the second pole piece 2, and improving reliability.

[0273] In some embodiments, the first insulating component 4 is further connected to the active material layer 20 .

[0274] In some examples, the first insulating component 4 may be connected to the end surface of the active material layer 20 facing the first connecting portion 31 ; alternatively, the first insulating component 4 may also be connected to the surface of the active material layer 20 facing away from the metal layer 12 to cover a portion of the active material layer 20 .

[0275] The embodiment of the present application can further improve the connection strength between the first insulating component 4 and the first pole piece 1 , reduce the risk of the first insulating component 4 falling off from the first pole piece 1 , and improve reliability.

[0276] In some embodiments, the first insulating member 4 covers a portion of the active material layer 20. The first insulating member 4 can cover the edge region of the active material layer 20 to constrain the edge region of the active material layer 20 and reduce the risk of collapse or falling off of the edge region of the active material layer 20 due to stress concentration.

[0277] As an example, the portion of the first insulating member 4 covering the active material layer 20 may be connected to the active material layer 20 , or may simply be attached to the active material layer 20 without being fixed to the active material layer 20 .

[0278] In some embodiments, the first insulating component 4 is configured to block the passage of ions.

[0279] In some examples, the first electrode sheet 1 is a positive electrode sheet. Due to assembly errors, the edge of the active material layer 20 toward the first connecting portion 31 may extend beyond the negative electrode active material layer of the negative electrode sheet, causing the risk of ion precipitation in the negative electrode active material layer. The first insulating component 4 can block the passage of ions, thereby reducing the number of ions that migrate to the negative electrode active material layer during charging and reducing the risk of ion precipitation.

[0280] In other examples, the first electrode sheet 1 is a negative electrode sheet. Due to assembly errors, the positive electrode active material layer may extend beyond the edge of the active material layer 20 toward the first connecting portion 31, causing the risk of ion precipitation in the active material layer 20. The first insulating component 4 can block the passage of ions, thereby reducing the movement of ions embedded in the active material layer 20 during charging and reducing the risk of ion precipitation.

[0281] In some embodiments, the active material layer 20 includes a first active material portion 21 and a second active material portion 22 arranged along a first direction Z, the first active material portion 21 is located on the side of the second active material portion 22 facing the first connecting portion 31, and the thickness of the first active material portion 21 at one end away from the second active material portion 22 is less than the thickness of the second active material portion 22.

[0282] In some examples, the first active material portion 21 may be of substantially uniform thickness, with the thickness of the first active material portion 21 being less than the thickness of the second active material portion 22, such that the first active material portion 21 and the second active material portion 22 form a stepped structure. In other examples, the thickness of the first active material portion 21 may decrease in steps, such that the first active material portion 21 has a stepped structure. In still other examples, the thickness of the first active material portion 21 may decrease gradually away from the second active material portion 22, such that the thickness of the first active material portion 21 decreases gradually, resulting in a more rounded or smoother appearance.

[0283] During the forming process of the first electrode sheet 1 , the active material layer 20 can be rolled to compact the active material layer 20 ; and the provision of the first active material portion 21 can reduce the rolling pressure on the edge of the active material layer 20 , thereby reducing the risk of cracking at the edge of the active material layer 20 .

[0284] In some embodiments, the thickness of the first active material portion 21 decreases along the direction from the active material layer 20 to the first connection portion 31 .

[0285] In some embodiments, the thickness of the first active material portion 21 at one end facing the second active material portion 22 is less than or equal to the thickness of the second active material portion 22 .

[0286] In some embodiments, the first insulating component 4 covers at least a portion of the first active material portion 21. The first active material portion 21 has a relatively small thickness. Covering the first insulating component 4 on the first active material portion 21 can improve space utilization in the thickness direction Y of the current collector, reduce the pressure on the first insulating component 4 when the electrode assembly 101 expands, reduce stress concentration, and reduce the risk of the active material layer 20 being crushed by the first insulating component 4, thereby improving the cycle performance of the battery cell 100.

[0287] In some embodiments, the first insulating member 4 is attached to the first active material portion 21 . Alternatively, the first insulating member 4 is attached to the first active material portion 21 .

[0288] In some embodiments, along the direction from the first active material portion 21 to the second active material portion 22 , the first insulating component 4 does not protrude beyond the boundary between the first active material portion 21 and the second active material portion 22 .

[0289] In some embodiments, in the first direction Z, the first insulating component 4 is spaced apart from the second active material portion 22 .

[0290] Optionally, the first insulating component 4 has a first end facing the second active material portion 22 , pointing along the metal layer 12 toward the active material layer 20 , and the first end does not extend beyond the surface of the second active material portion 22 facing away from the metal layer 12 .

[0291] In some embodiments, along the first direction Z, a size H of a portion of the first insulating component 4 covering the active material layer 20 is 0.2 mm ≤ H ≤ 1 mm.

[0292] In some examples, the value of H may be 0.2 mm, 1 mm, or any value between 0.2 mm and 1.0 mm. For example, the value of H may be, but is not limited to, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0293] Optionally, 0.3mm≤H≤0.8mm.

[0294] Limiting H to be greater than or equal to 0.2 mm allows the first insulating component 4 to cover the end surface of the active material layer 20 facing the first connecting portion 31 , thereby blocking burrs around the end surface of the active material layer 20 facing the first connecting portion 31 and improving the reliability of the battery cell 100 .

[0295] By limiting H to be greater than or equal to 0.2 mm, the first insulating member 4 can protect the edge region of the active material layer 20 and reduce the risk of material falling from the edge region of the active material layer 20 .

[0296] Limiting H to less than or equal to 1 mm can limit the area of the active material layer 20 covered by the first insulating component 4, reducing capacity loss. Furthermore, limiting H to less than or equal to 1 mm can minimize the amount of first insulating component 4 covering the active material layer 20, thereby reducing the weight and volume of the first insulating component 4 and mitigating the impact of the first insulating component 4 on the energy density of the battery cell 100.

[0297] In the embodiment of the present application, H is limited to 0.2 mm-1 mm, which can take into account both the reliability and energy density of the battery cell 100.

[0298] In some embodiments, the first connection portion 31 is welded to the surface of the metal layer 12 facing away from the insulating substrate 11 to form a first weld mark 51. The first weld mark 51 can transmit current between the first connection portion 31 and the metal layer 12, thereby improving the current flow capacity and reducing heat generation.

[0299] In some embodiments, along the first direction Z, the first weld mark 51 is spaced apart from the active material layer 20 , so that the first connection portion 31 is not easily welded to the active material layer 20 , which is beneficial to reducing the risk of problems such as cold solder joints and improving the connection reliability and current carrying capacity of the metal layer 12 and the conductive component 30 .

[0300] In some embodiments, along the first direction Z, a distance between the first weld mark 51 and the active material layer 20 is S1, where 0.3 mm ≤ S1 ≤ 5 mm.

[0301] The value of S1 can be 0.3mm, 5mm, and any value between 0.3mm and 5mm. For example, the value of S1 can be, but is not limited to, 0.3mm, 0.5mm, 1mm, 2mm, 2.5mm, 2.8mm, 3mm, 4mm, and 5mm.

[0302] Setting S1 to be greater than or equal to 0.3 mm allows a distance between the first weld mark 51 and the active material layer 20, reducing the risk of the conductive member 30 being welded to the active material layer 20, reducing problems such as cold solder joints, and helping to improve the connection reliability between the first connection portion 31 and the metal layer 12; setting S1 to be less than or equal to 5 mm prevents the distance between the first weld mark 51 and the active material layer 20 from being too large. When the size of the metal layer 12 along the first direction Z is constant, the active material layer 20 can cover a larger area, which helps to increase the coverage area of the active material layer 20 on the metal layer 12 and improve the energy density of the battery cell 100.

[0303] In some embodiments, 0.5 mm ≤ S1 ≤ 2.8 mm, the distance between the active material layer 20 and the first weld mark 51 is more reasonable, which can better balance the connection reliability of the conductive component 30 and the energy density of the battery cell 100 .

[0304] 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 conductive component 30 and the active material layer 20 to reduce the risk of lithium plating caused by the contact between the conductive component 30 and the active material layer 20. In addition, a spacing space can be provided between the first weld mark 51 and the first end face of the first connecting portion 31 facing the active material layer 20, so that the first weld mark 51 does not extend to the first end face 31a of the first connecting portion 31, reducing the risk of the first connecting portion 31 being welded through or cracked at the first end face 31a, which is beneficial to reducing burrs generated by welding and improving the reliability of the battery cell 100.

[0305] In some examples, the first electrode sheet 1 is a negative electrode sheet, and a gap exists between the first weld mark 51 and the active material layer 20. This provides space between the first weld mark 51 and the first end surface 31a of the first connecting portion 31, preventing the first weld mark 51 from extending to the first end surface 31a of the first connecting portion 31. This reduces the risk of weld penetration or cracking at the first end surface 31a of the first connecting portion 31, helps reduce burrs generated by welding, and improves the reliability of the battery cell 100. The conductive member 30 may or may not be in contact with the active material layer 20.

[0306] In some embodiments, along the first direction Z, the first weld mark 51 is spaced apart from the first end surface 31 a of the first connecting portion 31 .

[0307] A certain distance is spaced between the first weld mark 51 and the first end surface 31a of the first connecting portion 31, so that the first weld mark 51 does not extend to the first end surface 31a of the first connecting portion 31, thereby reducing the risk of the first end surface 31a of the first connecting portion 31 being welded through or cracked, thereby reducing burrs generated by welding and improving the reliability of the battery cell 100.

[0308] In some embodiments, along the first direction Z, a distance between the first weld mark 51 and the first end surface 31 a of the first connecting portion 31 is in a range of S2, where 0.3 mm ≤ S2 ≤ 1.2 mm.

[0309] Limiting S2 to a value greater than or equal to 0.3 mm ensures a gap between the first weld mark 51 and the first end surface 31a of the first connecting portion 31, preventing the first weld mark 51 from extending to the first end surface 31a of the first connecting portion 31. This reduces the risk of weld penetration or cracking of the first end surface 31a of the first connecting portion 31. Limiting S2 to a value less than or equal to 1.2 mm prevents excessive gaps between the first weld mark 51 and the first end surface 31a of the first connecting portion 31. This helps increase the coverage area of the active material layer 20 on the metal layer 12, thereby improving the energy density of the battery cell 100.

[0310] The value of S2 can be 0.3 mm, 1.2 mm, or any value between 0.3 mm and 1.2 mm. For example, the value of S2 can be, but is not limited to, 0.3 mm, 0.6 mm, 0.8 mm, 1 mm, or 1.2 mm.

[0311] Limiting S2 to 0.3 mm to 1.2 mm can better balance the reliability and energy density of the battery cell 100.

[0312] In some embodiments, the first insulating component 4 covers at least a portion of the first weld mark 51. The first insulating component 4 covers the surface of the first connecting portion 31 facing away from the metal layer 12 and covers at least a portion of the first weld mark 51. The first insulating component 4 may cover a portion of the first weld mark 51 or the entire first weld mark 51.

[0313] Optionally, the first insulating component 4 completely covers the first weld mark 51 .

[0314] After the first connecting portion 31 is welded to the metal layer 12, it is easy to produce pointed protrusions, metal debris and other components on the surface of the first weld mark 51. The first insulating component 4 of the embodiment of the present application covers the surface of the first weld mark 51, which can reduce the risk of burrs, metal debris and other components on the surface of the first weld mark 51 piercing the isolation member 3, thereby reducing the risk of burrs, metal debris and other components contacting the second pole piece 2, reducing the short circuit risk of the battery cell 100, and improving the reliability of the battery cell 100.

[0315] In some embodiments, the first insulating component 4 is connected to the first electrode piece 1. The first insulating component 4 may be connected to the metal layer 12, the conductive member 30, or the active material layer 20. For example, the first insulating component 4 may be connected to the first electrode piece 1 by bonding or attaching.

[0316] Connecting the first insulating component 4 to the first pole piece 1 can fix the first insulating component 4 , thereby stably blocking the burrs on the first end surface 31 a , which is beneficial to improving the reliability of the battery cell 100 .

[0317] In some embodiments, along the first direction Z, the first insulating component 4 has a dimension W, 3 mm ≤ W ≤ 9 mm.

[0318] The value of W can be 3mm, 9mm, and any value between 3mm and 9mm. For example, the value of W can be, but is not limited to, 3mm, 4mm, 4.5mm, 5mm, 6mm, 6.5mm, 7mm, 8mm, and 9mm.

[0319] Limiting W to be greater than or equal to 3 mm allows the first insulating component 4 to have a certain size, and the first insulating component 4 can better block the burrs at the first end surface 31a, thereby improving the internal insulation effect of the battery cell 100; limiting W to be less than or equal to 9 mm can limit the size of the first insulating component 4 along the first direction Z, which is beneficial to reducing the volume and weight occupied by the first insulating component 4 and improving the energy density of the battery cell 100.

[0320] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell 100 can be taken into consideration.

[0321] In some embodiments, 4.5 mm ≤ W ≤ 6.5 mm. Along the first direction Z, the size of the first insulating component 4 is relatively reasonable, which can better balance the insulation reliability and energy density of the battery cell 100.

[0322] In some embodiments, the first insulating component 4 is a uniform width structure.

[0323] In some embodiments, the first insulating member 4 may be a rectangular tape.

[0324] In some embodiments, the conductive component 30 further includes at least one second connection portion 32 connected to the first connection portion 31 . In the first direction Z, the second connection portion 32 is located on the side of the first connection portion 31 facing away from the active material layer 20 . The second connection portion 32 is electrically connected to the electrode lead portion 2011 .

[0325] Exemplarily, the first connecting portion 31 and the second connecting portion 32 are arranged and connected along the first direction Z. Along the direction from the active material layer 20 to the first connecting portion 31 , the second connecting portion 32 entirely protrudes from the metal layer 12 .

[0326] The second connecting portion 32 and the electrode lead portion 2011 can be connected by direct welding, or by welding with a conductive member (e.g., an adapter). Welding is convenient for connection and manufacturing. Of course, the second connecting portion 32 and the electrode lead portion 2011 can also be connected by other methods.

[0327] In some examples, the first connection portion 31 may be covered on the metal layer 12 and welded to the metal layer 12, and the second connection portion 32 may be led out along the first direction Z from one end of the first connection portion 31 facing away from the active material layer 20 to protrude out of the insulating base 11; along the thickness direction Y of the current collector 10, the projection of the first connection portion 31 is located within the projection of the metal layer 12, and the projection of the second connection portion 32 is located outside the projection range of the metal layer 12; the connection positions of the metal layer 12 and the electrode lead portion 2011 on the conductive component 30 are different, which facilitates connection and can also reduce the mutual influence between the two connections, which is beneficial to connection reliability.

[0328] In some cases, in a wound electrode assembly 101, the insulating base 11 separates the insulation of two adjacent metal layers 12, making it difficult for the two adjacent metal layers 12 to be directly connected across the insulating base 11 and transmit current to the outside, 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 component 30 to be welded to the metal layer 12, and the second connecting portion 32 of the conductive component 30 protrudes out of the insulating base 11, so that 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 base 11, which can effectively improve the conductivity of the first electrode 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.

[0329] In the case of a laminated electrode assembly 101, the insulating substrate 11 insulates and separates two adjacent metal layers 12, making it difficult for the two adjacent metal layers 12 to directly connect and transmit current outward, resulting in poor conductivity, low fast-charging performance, and easy 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 metal layer 12, 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.

[0330] The second connecting portion 32 protrudes out of the metal layer 12, which can facilitate the connection between the second connecting portion 32 and the electrode lead portion 2011, making processing and manufacturing more convenient; at the same time, it can also reduce the risk of problems such as cold welding, which is beneficial to improving the connection reliability between the metal layer 12 and the conductive component 30, and is also beneficial to improving the current flow capacity of the first pole piece 1, thereby improving the fast charging performance of the battery cell 100.

[0331] In some embodiments, the first connection portion 31 and the second connection portion 32 are both one.

[0332] In other embodiments, the first connecting portion 31 includes multiple first connecting sub-portions 311, which are spaced apart along a second direction X. The second direction X is perpendicular to the first direction Z and the thickness direction Y of the current collector. Each first connecting sub-portion 311 is connected to the metal layer 12. There are multiple second connecting portions 32, and each first connecting sub-portion 311 is connected to each second connecting portion 32 in a one-to-one correspondence.

[0333] By providing a plurality of second connection portions 32 , the flow area can be increased, the flow capacity of the conductive component 30 can be enhanced, the fast charging performance of the battery cell 100 can be improved, the heat generation of the battery cell 100 can be reduced, and the reliability of the battery cell 100 can be improved.

[0334] In some embodiments, the current collector 10 includes two metal layers 12 disposed on opposite sides of the insulating substrate 11 along the thickness direction Y of the current collector. The first pole piece 1 includes two active material layers 20 and two conductive members 30 . The two active material layers 20 are respectively disposed on the two metal layers 12 , and the first connecting portions 31 of the two conductive members 30 are respectively connected to the two metal layers 12 .

[0335] The two conductive components 30 can respectively lead out the current of the two metal layers 12 , thereby increasing the current capacity and improving the fast charging performance of the battery cell 100 .

[0336] In some embodiments, the electrode assembly 101 includes two first insulating parts 4 , which are respectively attached to the first connecting portions 31 of the two conductive members 30 .

[0337] The two first insulating components 4 may be directly connected or not directly connected.

[0338] The two first insulating components 4 can respectively cover the burrs on the first end surfaces 31 a of the two first connecting portions 31 , thereby reducing the possibility of the burrs piercing the separator 3 and contacting the second pole piece 2 , thereby reducing the risk of short circuit.

[0339] In some embodiments, a portion of the two first insulating components 4 is fitted together to reduce the risk of burrs extending from between the two first insulating components 4 and improve reliability.

[0340] In some embodiments, parts of the two first insulating components 4 are connected to improve the stability of the first insulating components 4 and reduce the risk of the first insulating components 4 falling off from the first pole piece 1 .

[0341] In some embodiments, parts of the two first insulating components 4 are attached and connected.

[0342] In some embodiments, the conductive member 30 further includes a second connecting portion 32 connected to the first connecting portion 31. In the first direction Z, the second connecting portion 32 is located on 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. The second connecting portions 32 of the two conductive members 30 are welded to form a second weld mark 52.

[0343] In some examples, along the direction of the active material layer 20 toward the first connection portion 31, the portion of the conductive member 30 protruding from the metal layer 12 forms the second connection portion 32, so that the second connection portions 32 of the two conductive members 30 can be directly brought into close proximity and welded together, leaving a trace of the welding, which is the second weld mark 52. The second connection portions 32 of the two conductive members 30 can be welded by ultrasonic welding, laser welding, or the like.

[0344] The second connecting portion 32 of the two conductive components 30 can 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.

[0345] In some embodiments, the metal layer 12 includes a first metal portion 121 and a second metal portion 122 arranged and connected along a first direction Z. The first metal portion 121 is covered with the active material layer 20, and the second metal portion 122 is not covered with the active material layer 20. The first connecting portion 31 is welded to the second metal portion 122 to form a first weld mark 51.

[0346] As an example, a dimension of the second metal part 122 along the second direction X may be smaller than or equal to a dimension of the first metal part 121 along the second direction X.

[0347] The first connection portion 31 is stacked on the surface of the metal layer 12 facing away from the insulating base 11 and welded to the surface of the metal layer 12 facing away from the insulating base 11 . The trace formed by the welding is the first weld mark 51 .

[0348] Welding the second metal portion 122 to the first connecting portion 31 simplifies the manufacturing process of the first electrode 1 and improves the current flow capacity between the metal layer 12 and the first connecting portion 31. Providing the second metal portion 122 without covering the active material layer 20 can reduce the impact of welding on the active material layer 20.

[0349] The thickness of the metal layer 12 is small, and the surface of the metal layer 12 facing away from the insulating substrate 11 is large; stacking and welding the first connecting part 31 and the second metal part 122 can increase the welding area between the conductive component 30 and the metal layer 12, and increase the flow area between the conductive component 30 and the metal layer 12, thereby increasing the flow capacity of the first electrode 1 and improving the fast charging performance of the battery device 1100.

[0350] In some embodiments, the thickness of the first connection portion 31 is greater than the thickness of the second metal portion 122 .

[0351] In some embodiments, the thickness of the conductive member 30 is greater than the thickness of the metal layer 12 .

[0352] In some embodiments, the second metal portion 122 includes at least one protrusion 1221 , and along the second direction X, the sum of the sizes of all the protrusions 1221 is smaller than that of the first metal portion 121 . The second direction X is perpendicular to the first direction Z and the thickness direction Y of the current collector.

[0353] In some examples, the second metal portion 122 includes a protrusion 1221 .

[0354] In some other examples, the second metal portion 122 includes a plurality of protrusions 1221 , and the plurality of protrusions 1221 are arranged along the second direction X at intervals.

[0355] For example, the dimension of the first metal portion 121 along the second direction X is L1, and the dimension of the end of the protrusion 1221 facing the first metal portion 121 along the second direction X is l1. The number of protrusions 1221 is n, where n is a positive integer. L1>n×l1. Alternatively, n is 1, 2, 4, 5, 8, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, or 100.

[0356] The protrusion 1221 may be directly connected to the first metal portion 121 , or may be indirectly connected to the first metal portion 121 through other portions of the second metal portion 122 .

[0357] In some embodiments, the first connecting portion 31 includes at least one first connecting sub-portion 311 . The first connecting sub-portion 311 is located on a side of the protrusion 1221 away from the insulating base 11 . The first connecting sub-portion 311 corresponds to the protrusion 1221 one-to-one.

[0358] For example, the first connecting sub-portion 311 may be a portion of the first connecting portion 31 that overlaps with the protrusion 1221 in the thickness direction Y of the current collector.

[0359] The first connecting sub-portion 311 covers the protruding portion 1221. The first connecting sub-portion 311 may completely cover the protruding portion 1221, or may only cover a portion of the protruding portion 1221.

[0360] The number of first connecting sub-portions 311 can be the same as the number of protrusions 1221. In some examples, there is one first connecting sub-portion 311 and one protrusion 1221. In other examples, there are multiple first connecting sub-portions 311 and multiple protrusions 1221, and the multiple first connecting sub-portions 311 are provided in a one-to-one correspondence with the multiple protrusions 1221.

[0361] The first connecting sub-portion 311 may be directly fixed to the protruding portion 1221 , for example, the first connecting sub-portion 311 may be welded to the protruding portion 1221 . Alternatively, the first connecting sub-portion 311 may also be simply attached to the protruding portion 1221 .

[0362] The protrusion 1221 can reduce the space and volume occupied by the first pole piece 1, thereby increasing the energy density of the battery cell 100. The first connecting sub-portion 311 can increase the flow area between the first connecting portion 31 and the second metal portion 122, thereby increasing the flow capacity.

[0363] In some embodiments, the first connecting sub-portion 311 completely covers the protruding portion 1221 .

[0364] In some embodiments, there are multiple protrusions 1221 , which are spaced apart along the second direction X. The first connecting portion 31 includes multiple first connecting sub-portions 311 , which are spaced apart along the second direction X, and the multiple first connecting sub-portions 311 correspond one-to-one to the multiple protrusions 1221 .

[0365] By providing a plurality of protrusions 1221 and a plurality of first connecting sub-parts 311 , the flow area between the first connecting part 31 and the second metal part 122 can be increased, the flow capacity can be improved, and the fast charging performance of the battery cell 100 can be improved.

[0366] For example, the plurality of protrusions 1221 are arranged at intervals along the second direction X, which is conducive to dividing the first metal part 121 into a plurality of regions along the second direction X, and one region may correspond to one protrusion 1221. The electrons in each region may be transmitted to the electrode lead-out portion 2011 via the corresponding protrusion 1221, so that the electrons of the first metal part 121 are transmitted in different regions, and the electron transmission path in each region is short to the corresponding protrusion 1221, which is conducive to reducing the transmission distance of the electrons, reducing the overall resistance of the first electrode sheet 1, and improving the fast performance and reliability of the battery cell 100.

[0367] In some examples, after the first pole piece 1 is wound or stacked, multiple protrusions 1221 are stacked together, and multiple second connecting portions 32 are also stacked together, thereby breaking the insulation limitation of the insulating substrate 11, which can effectively improve the conductivity of the first pole piece 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.

[0368] In some embodiments, there are multiple second connecting portions 32, and each first connecting sub-portion 311 is connected to each second connecting portion 32 in a one-to-one correspondence; each first connecting sub-portion 311 is welded to the surface of each protrusion 1221 facing away from the insulating base 11. The number of first connecting sub-portions 311, the number of second connecting portions 32, and the number of protrusions 1221 are the same: one first connecting sub-portion 311 corresponds to one protrusion 1221, and one first connecting sub-portion 311 is connected to one second connecting portion 32.

[0369] In some embodiments, the first insulating component 4 includes at least one first insulator portion 41 . The first insulator portion 41 covers the surface of the first connecting sub-portion 311 facing away from the protruding portion 1221 . The first insulator portion 41 corresponds to the first connecting sub-portion 311 one-to-one.

[0370] For example, the first insulator portion 41 may be a portion of the first insulating member 4 that overlaps with the first connector portion 311 in the thickness direction Y of the current collector.

[0371] The first insulating portion 41 may completely cover the first connecting portion 311 , or may only cover a portion of the first connecting portion 311 .

[0372] The number of first connectors 311, the number of protrusions 1221, and the number of first insulator portions 41 can be the same. In some examples, there is one first connector 311, one protrusion 1221, and one first insulator portion 41. In other examples, there are multiple first connectors 311, one protrusion 1221, and one first insulator portion 41, with the multiple first connectors 311 corresponding to the multiple protrusions 1221, and the multiple first insulator portions 41 corresponding to the multiple first connectors 311.

[0373] The first insulating portion 41 may cover the first connecting portion 311 to reduce the risk of electrical conduction between the first connecting portion 311 and the second electrode piece 2 , thereby improving the reliability of the battery cell 100 .

[0374] In some embodiments, the first insulating sub-part 41 completely covers the first connecting sub-part 311 .

[0375] In some embodiments, there are multiple protrusions 1221, and the multiple protrusions 1221 are spaced apart along the second direction X. The first connecting portion 31 includes multiple first connecting sub-portions 311, and the multiple first connecting sub-portions 311 are spaced apart along the second direction X, and the multiple first connecting sub-portions 311 correspond one-to-one with the multiple protrusions 1221. The first insulating component 4 includes multiple first insulator portions 41 arranged along the second direction X, and the first insulator portions 41 cover the surface of the first connecting sub-portions 311 facing away from the protrusions 1221, and the first insulator portions 41 correspond one-to-one with the first connecting sub-portions 311.

[0376] The plurality of first insulating sub-portions 41 respectively cover the plurality of first connecting sub-portions 311 to reduce the risk of conduction between the first connecting sub-portions 311 and the second pole piece 2 , thereby improving the reliability of the battery cell 100 .

[0377] In some embodiments, the first insulating component 4 further includes a second insulator portion 42 connected to the first insulator portion 41 . Along the first direction Z, the second insulator portion 42 is located on a side of the first insulator portion 41 facing the active material layer 20 .

[0378] There may be one or more second insulator portions 42. In some examples, there is one second insulator portion 42 that extends continuously along the second direction X, and the second insulator portion 42 connects to the plurality of first connecting sub-portions 311. In other examples, there are multiple second insulator portions 42, and the plurality of second insulator portions 42 are provided in a one-to-one correspondence with the plurality of first insulator portions 41.

[0379] By providing the second insulator portion 42, the first insulating component 4 can protrude from the first connector portion 311 in the direction from the first connector portion 31 to the active material layer 20, thereby reducing the risk of electrical conduction between the first connector portion 311 and the second pole piece 2. Furthermore, the second insulator portion 42 can also cover burrs on the first end surface 31a, thereby reducing the possibility of burrs piercing the separator 3 and contacting the second pole piece 2, thereby reducing the risk of short circuits.

[0380] In some embodiments, the second insulator portion 42 may be spaced apart from the metal layer 12 or may be attached to the metal layer 12. Optionally, at least a portion of the second insulator portion 42 is attached to a portion of the metal layer 12 between the first connecting portion 31 and the active material layer 20.

[0381] In some embodiments, one end of the second insulator portion 42 away from the first insulator portion 41 may be covered by the active material layer 20 .

[0382] In some embodiments, the first insulating component 4 includes a plurality of first insulator portions 41 arranged along the second direction X. The second insulator portion 42 continuously extends along the second direction X and is connected to the plurality of first insulator portions 41 .

[0383] The second insulator parts 42 are continuously provided to increase the insulation area and reduce the risk of short circuit. The second insulator parts 42 connect the multiple first insulator parts 41 into a whole, thereby reducing the risk of the first insulator parts 41 falling off from the first connecting sub-part 311 and improving insulation reliability.

[0384] In some embodiments, the first insulating component 4 further includes a third insulator portion 43 connected to the first insulator portion 41 , and the third insulator portion 43 and the first insulator portion 41 are arranged along the second direction X.

[0385] There may be one or more third insulator parts 43 .

[0386] By providing the third insulating portion 43, the first insulating component 4 can protrude from the first connecting sub-portion 311 in the second direction X, thereby covering the burrs at the end of the first connecting sub-portion 311 along the second direction X, reducing the possibility of the burrs piercing the isolating member 3 and contacting the second pole piece 2, thereby reducing the risk of short circuit and improving the reliability of the battery cell 100.

[0387] In some embodiments, there are multiple third insulator parts 43 , and both ends of the first insulator part 41 along the second direction X are connected to the third insulator parts 43 . The first insulating component 4 may cover both ends of the first connecting sub-part 311 along the second direction X.

[0388] In some embodiments, in the thickness direction Y of the current collector, the third insulator portion 43 overlaps neither the current collector 10 nor the conductive member 30 .

[0389] In some embodiments, there are two first insulating components 4, each of which is attached to the first connecting portions 31 of the two conductive members 30. The third insulator portions 43 of the two first insulating components 4 fit closely together to reduce the risk of burrs extending from between the two third insulator portions 43 and improve reliability.

[0390] As an example, the third insulator portions 43 of the two first insulating components 4 can be bonded together by gluing, static adsorption or other methods.

[0391] After the third insulating parts 43 of the two first insulating components 4 are attached together, the metal debris at both ends of the first connecting sub-part 311 along the second direction X can be covered, so that the metal debris is not easy to fall into the electrode assembly 101, which can better reduce the risk of short circuit of the battery cell 100.

[0392] In some embodiments, the third insulator portions 43 of the two first insulating components 4 are connected to improve the stability of the first insulating components 4 and reduce the risk of the first insulating components 4 falling off from the first pole piece 1 .

[0393] In some embodiments, the third insulator portions 43 of the two first insulating components 4 are attached and connected. Alternatively, the third insulator portions 43 of the two first insulating components 4 are bonded.

[0394] In some embodiments, the first insulating component 4 includes a plurality of third insulator portions 43 arranged along the second direction X, and two ends of each first insulator portion 41 along the second direction X are respectively connected to two third insulator portions 43 .

[0395] The two third insulating portions 43 can respectively cover the burrs at both ends of the first connecting portion 311 along the second direction X, thereby reducing the possibility of the burrs piercing the isolation member 3 and contacting the second pole piece 2, reducing the short circuit risk, and improving the reliability of the battery cell 100.

[0396] In some embodiments, the plurality of third insulator portions 43 of the two first insulating components 4 are arranged in a one-to-one correspondence.

[0397] In some embodiments, the plurality of first insulator portions 41 and the plurality of third insulator portions 43 are alternately arranged along the second direction X, and two adjacent first insulator portions 41 are connected by one third insulator portion 43 .

[0398] The plurality of third insulator parts 43 connect the plurality of first insulator parts 41 into one, which can not only increase the insulation area, but also reduce the risk of the first insulator part 41 falling off from the first connecting sub-part 311, thereby improving insulation reliability.

[0399] The first insulating component 4 is continuously provided as a whole, which can restrain the first connecting sub-part 311, reduce deformation of the first connecting sub-part 311, and prevent the first connecting sub-part 311 from being inserted upside down between the active material layer 20 and the second electrode 2, thereby reducing the risk of short circuit.

[0400] In some embodiments, the first insulating component 4 further includes a fourth insulator portion 44 connected to the first insulator portion 41 . Along the first direction Z, the fourth insulator portion 44 is located on a side of the first insulator portion 41 facing away from the active material layer 20 .

[0401] There may be one or more fourth insulator parts 44 .

[0402] As an example, the fourth insulator portion 44 and the second insulator portion 42 are connected to two ends of the first insulator portion 41 along the first direction Z, respectively.

[0403] In the direction from the active material layer 20 to the first connecting portion 31, the fourth insulating portion 44 entirely extends beyond the first connecting portion 311. By providing the fourth insulating portion 44, the insulation effect can be improved.

[0404] In some embodiments, the fourth insulator portion 44 may be attached to the conductive member 30. As an example, the fourth insulator portion 44 is attached to the second connecting portion 32.

[0405] In some embodiments, the first insulating component 4 further includes a plurality of first insulator portions 41 and a plurality of fourth insulator portions 44. The plurality of first insulator portions 41 and the plurality of fourth insulator portions 44 are arranged in a one-to-one correspondence, and the first insulator portion 41 is connected to the corresponding fourth insulator portion 44. In the first direction Z, the fourth insulator portion 44 is located on the side of the first insulator portion 41 facing away from the active material layer 20.

[0406] Optionally, the first insulating component 4 further includes a plurality of third insulator portions 43 , the plurality of third insulator portions 43 and the plurality of fourth insulator portions 44 are alternately arranged along the second direction X, and two adjacent fourth insulator portions 44 are connected by one third insulator portion 43 .

[0407] In some embodiments, the first connecting sub-portion 311 is welded to the protruding portion 1221 to form a first weld portion 511 . The first weld portion 51 includes the first weld portion 511 . The first insulating sub-portion 41 covers at least a portion of the first weld portion 511 .

[0408] Exemplarily, the first connecting sub-portion 311 is stacked on the surface of the protruding portion 1221 facing away from the insulating base 11 and is welded to the protruding portion 1221 . The trace formed by the welding is the first weld mark 511 .

[0409] In some examples, the first connecting sub-portion 311 may be welded to the protrusion 1221 as a whole; alternatively, in other examples, a portion of the first connecting sub-portion 311 may be welded to the protrusion 1221 , while another portion may not be welded to the protrusion 1221 .

[0410] In some examples, the first connection portion 31 may be welded only to the protrusion 1221 . Alternatively, the first connection portion 31 may also be welded to other portions of the metal layer 12 .

[0411] The first insulator portion 41 may cover a portion of the first weld portion 511 , or may cover the entire first weld portion 511 .

[0412] As an example, the first welding portion 511 may be an integrated structure. Alternatively, the first welding portion 511 may also include a plurality of welding points or welding lines arranged at intervals.

[0413] The first connecting sub-portion 311 and the protrusion 1221 are connected by welding, which is a simple connection method and facilitates the production of the first pole piece 1; the first welding portion 511 can be directly used for current flow between the first connecting sub-portion 311 and the protrusion 1221, which is beneficial to improving the current flow capacity between the first connecting sub-portion 311 and the protrusion 1221; the first insulating sub-portion 41 can block burrs, metal debris and other structures on the first welding portion 511, thereby reducing the risk of these structures passing through the isolation member 3 and contacting the second pole piece 2, which is beneficial to improving the reliability of the battery cell 100.

[0414] In some embodiments, both ends of the first welded portion 511 do not extend beyond the first insulator portion 41 along the first direction Z. This embodiment of the present application can reduce the exposed area of the first welded portion 511 , lowering the risk of the first welded portion 511 puncturing the separator 3 , and improving the reliability of the battery cell 100 .

[0415] In some embodiments, along the second direction X, both ends of the first weld portion 511 do not extend beyond the first insulator portion 41 .

[0416] In some embodiments, the first weld mark 511 extends from one side of the protruding portion 1221 to the other side of the protruding portion 1221 along the second direction X. The large size of the first weld mark 511 along the second direction X helps to increase the flow area between the first connecting sub-portion 311 and the protruding portion 1221, improve the flow capacity between the first connecting sub-portion 311 and the protruding portion 1221, reduce the risk of heat generation, and improve the fast charging performance and reliability of the battery cell 100.

[0417] In some embodiments, in the thickness direction Y of the current collector, the projection of the first weld print 511 falls within the projection of the protrusion 1221 .

[0418] In some embodiments, there are multiple first connecting sub-portions 311 and protruding portions 1221, and they are arranged in a one-to-one correspondence. Correspondingly, there are also multiple first welding portions 511, and the multiple first welding portions 511 are arranged in a one-to-one correspondence with the multiple first connecting sub-portions 311.

[0419] In some embodiments, during the fabrication of the first electrode sheet 1, the elongated conductive member may be welded to the edge of the current collector by ultrasonic welding (e.g., double-roll continuous ultrasonic welding or other welding methods), forming uniform-width weld marks. The conductive member is then cut using laser die-cutting or other cutting methods to form a predetermined shape, facilitating connection between the conductive member and the electrode lead. After cutting, the uniform-width weld marks form multiple first weld marks.

[0420] In some embodiments, the first insulating component 4 completely covers the first weld print 511 .

[0421] In some embodiments, the second metal portion 122 further includes a transition portion 1222 connected between the first metal portion 121 and the protruding portion 1221. Along the second direction X, a size of the transition portion 1222 is greater than the sum of sizes of all the protruding portions 1221.

[0422] Along the second direction X, the transition portion 1222 may have a dimension L2, and the end of the protrusion 1221 facing the transition portion 1222 may have a dimension l1 along the second direction X. The number of the protrusions 1221 is n, where n is a positive integer. L2>n×l1.

[0423] The first metal portion 121 , the transition portion 1222 and the protruding portion 1221 are arranged along the first direction Z.

[0424] In some embodiments, along the second direction X, the size of the first metal portion 121 is L1, the size of the transition portion 1222 is L2, and 0.8≤L2 / L1≤1.

[0425] 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.

[0426] In some examples, L2 = L1. Along the second direction X, the dimension L2 of the transition portion 1222 is equal to the dimension L1 of the first metal portion 121. Optionally, along the second direction X, both ends of the transition portion 1222 are flush with the first metal portion 121.

[0427] In other examples, L2 < L1. Optionally, along the second direction X, the transition portion 1222 may be located in the middle of the first metal portion 121, and both ends of the transition portion 1222 are not flush with both ends of the first metal portion 121. Alternatively, along the second direction X, the transition portion 1222 may be disposed toward one end of the first metal portion 121, such that one end of the transition portion 1222 is flush with one end of the first metal portion 121, and the other end of the transition portion 1222 is not flush with the other end of the first metal portion 121.

[0428] In some embodiments, the first connecting portion 31 includes a second connecting sub-portion 312 , which is located on the side of the transition portion 1222 facing away from the insulating substrate 11 along the thickness direction Y of the current collector, and the first connecting sub-portion 311 is connected to the end face of the second connecting sub-portion 312 away from the active material layer 20 .

[0429] The second connecting sub-section 312 may be one or more. In some examples, the first connecting sub-section 311 is multiple and spaced apart along the second direction X, and the second connecting sub-section 312 is one and extends continuously along the second direction X. The second connecting sub-section 312 connects the multiple first connecting sub-sections 311. In other examples, both the first connecting sub-section 311 and the second connecting sub-section 312 are multiple, and the multiple first connecting sub-sections 311 and the multiple second connecting sub-sections 312 are arranged in a one-to-one correspondence.

[0430] As an example, the second connecting sub-portion 312 and the transition portion 1222 may be directly fixedly connected, or may be simply fitted together without being directly fixed.

[0431] As an example, the second connecting sub-portion 312 is connected to the surface of the transition portion 1222 facing away from the insulating base 11 by welding, conductive adhesive bonding or other means, thereby achieving electrical connection between the second connecting sub-portion 312 and the transition portion 1222 .

[0432] During the circulation process of the battery cell 100, a portion of the current can be transmitted between the transition portion 1222 and the second connecting sub-portion 312, thereby reducing the overflow pressure between the protrusion 1221 and the first connecting sub-portion 311, which is beneficial to reducing the heat generation of the protrusion 1221 and improving the fast charging performance and usage reliability of the battery cell 100.

[0433] In some embodiments, the second connecting sub-portion 312 is connected to the transition portion 1222 .

[0434] For example, 0.8≤L2 / L1≤1. The larger the size L2 of the transition portion 1222 is, the larger the connection area between the transition portion 1222 and the second connecting sub-portion 312 can be set, and the better the flow capacity between the transition portion 1222 and the second connecting sub-portion 312 is.

[0435] Setting L2 / L1 to 0.8-1 can make the transition portion 1222 have a larger size along the second direction X, which is beneficial to increasing the connection area between the second connecting sub-portion 312 and the transition portion 1222, improving the flow capacity at the connection between the second connecting sub-portion 312 and the transition portion 1222, 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.

[0436] In some embodiments, L2 = L1. The embodiment of the present application allows the transition portion 1222 to have a larger dimension along the second direction X, which facilitates designing a larger connection area between the second connecting sub-portion 312 and the transition portion 1222. This maximizes the current flow capacity at the connection between the second connecting sub-portion 312 and the transition portion 1222, effectively improving the current flow capacity of the first pole piece 1, reducing heat generation in the battery cell 100, and improving the fast charging performance of the battery cell 100.

[0437] In some embodiments, there is one second connecting sub-portion 312 , and a dimension of the second connecting sub-portion 312 along the second direction X is equal to a dimension of the transition portion 1222 along the second direction X.

[0438] In some embodiments, the end surface of the second connecting sub-portion 312 facing the active material layer 20 along the first direction Z is the first end surface 31 a. The first insulating component 4 can block burrs on the first end surface 31 a, reducing the possibility of burrs piercing the separator 3 and contacting the second electrode 2, thereby reducing the risk of short circuit.

[0439] In some embodiments, the first insulating component 4 protrudes from the end surface of the second connecting sub-portion 312 facing away from the active material layer 20, along the direction from the first metal portion 121 to the second metal portion 122. The first insulating component 4 can block burrs on the end surface of the second connecting sub-portion 312 facing away from the active material layer 20, reducing the possibility of burrs piercing the separator 3 and contacting the second electrode 2, thereby reducing the risk of short circuits.

[0440] In some embodiments, at least a portion of the first insulating component 4 is attached to the second connecting sub-portion 312 .

[0441] In some embodiments, the first insulating component 4 includes a second insulator portion 42 , which covers the second connecting portion 312 and protrudes from the first end surface 31 a along a direction from the second metal portion 122 to the first metal portion 121 .

[0442] The first insulating component 4 may include a first insulator portion 41 , or may not include the first insulator portion 41 .

[0443] The second insulator portion 42 may completely cover the first end surface 31 a or may cover only a portion of the first end surface 31 a .

[0444] The second insulator portion 42 can block the burrs on the first end surface 31 a , reducing the possibility of the burrs piercing the isolation member 3 and contacting the second pole piece 2 , thereby reducing the risk of short circuit.

[0445] In some embodiments, the second insulating sub-portion 42 completely covers the second connecting sub-portion 312 .

[0446] In some embodiments, the second insulator portion 42 completely covers the transition portion 1222 .

[0447] In some embodiments, the second insulator portion 42 protrudes from the second connecting sub-portion 312 in the second direction X. The second insulator portion 42 can block burrs at both ends of the second connecting sub-portion 312 along the second direction X, reducing the possibility of burrs piercing the separator 3 and contacting the second pole piece 2, thereby reducing the risk of short circuit.

[0448] Optionally, the second insulator portion 42 extends continuously along the second direction X, the size of the second insulator portion 42 along the second direction X is larger than the size of the second connecting sub-portion 312 along the second direction X, and the size of the second insulator portion 42 along the second direction X is larger than the size of the transition portion 1222 along the second direction X.

[0449] Optionally, there are two first insulating components 4. Parts of the second insulating sub-parts 42 of the two first insulating components 4 protruding from the second connecting sub-part 312 in the second direction X are attached and bonded.

[0450] In some embodiments, the first insulating component 4 further includes a first insulator portion 41 and a third insulator portion 43, which are connected to the second insulator portion 42. In the first direction Z, the first insulator portion 41 and the third insulator portion 43 are both located on the side of the second insulator portion 42 facing away from the active material layer 20. The first insulator portion 41 covers the surface of the first connecting sub-portion 311 facing away from the protrusion 1221. The first insulator portion 41 and the third insulator portion 43 are arranged and connected along the second direction X.

[0451] The third insulating portion 43 can not only block the burrs on the end face of the second connecting sub-portion 312 away from the active material layer 20, but also block the burrs on the end of the first connecting sub-portion 311 along the second direction X, thereby reducing the possibility of the burrs piercing the isolation member 3 and contacting the second pole piece 2, reducing the risk of short circuit, and improving the reliability of the battery cell 100.

[0452] Optionally, there are multiple first insulator parts 41 and multiple third insulator parts 43. The multiple first insulator parts 41 and the multiple third insulator parts 43 are alternately arranged along the second direction X.

[0453] As an example, see Figure 14 and Figure 15 The boundaries between the first insulator portion 41, the second insulator portion 42, the third insulator portion 43, and the fourth insulator portion 44 are indicated by dashed lines D1, D2, D3, D4, D5, and D6. The dashed line D1 corresponds to the end surface of the second connector portion 312 facing the first connector portion 311, the dashed line D2 corresponds to the junction between the first connector portion 31 and the second connector portion 32 (the junction between the first connector portion 31 and the second connector portion 32 corresponds to the end surface of the protruding portion 1221 facing away from the transition portion 1222), D3 and D4 correspond to the two ends of the first connector portion 311 along the second direction X, and D5 and D6 correspond to the two ends of the second connector portion 32 along the second direction X.

[0454] In some embodiments, the second connecting sub-portion 312 is welded to the surface of the transition portion 1222 facing away from the insulating base 11 to form a second weld print portion 512 , and the first weld print 51 includes the second weld print portion 512 .

[0455] Exemplarily, the second connecting sub-portion 312 is welded to the surface of the transition portion 1222 facing away from the insulating base 11 , and a trace of welding between the transition portion 1222 and the second connecting sub-portion 312 is the second weld mark 512 .

[0456] In some examples, the first weld mark 51 may include only the second weld mark portion 512, that is, the first connection portion 31 is welded only to the transition portion 1222, but not to the protruding portion 1221. In other examples, the first weld mark 51 includes the second weld mark portion 512 and the first weld mark portion 511, and the second weld mark portion 512 is located between the first weld mark portion 511 and the active material layer 20, that is, the first connection portion 31 is welded to both the transition portion 1222 and the protruding portion 1221.

[0457] In some examples, the second connecting sub-portion 312 may be entirely welded to the transition portion 1222 ; alternatively, in other examples, a portion of the second connecting sub-portion 312 may be welded to the transition portion 1222 , while another portion may not be welded to the transition portion 1222 .

[0458] As an example, the second welding portion 512 may be an integral structure. Alternatively, the second welding portion 512 may also include a plurality of welding points or welding lines arranged at intervals.

[0459] The second connecting sub-portion 312 and the transition portion 1222 are connected by welding, which is a simple connection method and is conducive to facilitating the production of the first pole piece 1; in addition, the second connecting sub-portion 312 and the transition portion 1222 can be directly connected by the second weld portion 512 for current flow, which is conducive to improving the current flow capacity between the second connecting sub-portion 312 and the transition portion 1222 and reducing the heat generation of the battery cell 100.

[0460] In some embodiments, the second insulator portion 42 covers at least a portion of the second welded portion 512. The second insulator portion 42 can block burrs, metal debris, and other structures on the second welded portion 512, reducing the risk of these structures passing through the separator 3 and contacting the second pole piece 2, thereby improving the reliability of the battery cell 100.

[0461] In some embodiments, both ends of the second welded portion 512 do not extend beyond the second insulator portion 42 along the first direction Z. This embodiment of the present application can reduce the exposed area of the second welded portion 512 , lower the risk of the second welded portion 512 puncturing the separator 3 , and improve the reliability of the battery cell 100 .

[0462] In some embodiments, along the direction from the first connection portion 31 to the active material layer 20 , the second insulator portion 42 protrudes from the edge of the second weld portion 512 toward the active material layer 20 .

[0463] In some embodiments, along the thickness direction Y of the current collector, the projection of the second weld mark 512 falls within the projection of the first insulating component 4, so that the first insulating component 4 can completely cover the second weld mark 512. The first insulating component 4 can completely cover the second weld mark 512 and block burrs, metal debris, and other structures on the entire second weld mark 512, reducing the risk of these structures passing through the separator 3 and contacting the second electrode sheet 2, thereby improving the reliability of the battery cell 100.

[0464] In some embodiments, along the second direction X, the size of the transition portion 1222 is L2, the size of the second weld print 512 is L3, and 0.8≤L3 / L2≤1.

[0465] 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.

[0466] The larger L3 is, the larger the welding area between the transition portion 1222 and the second connecting sub-portion 312 is, and the better the current flow capacity at the connection between the transition portion 1222 and the first connecting portion 31 is. In the embodiment of the present application, L3 / L2 is set to 0.8-1, which can make the dimension of the transition portion 1222 along the second direction X larger, which is beneficial for increasing the connection area between the first connecting portion 31 and the transition portion 1222, improving the current flow capacity at the connection between the first connecting portion 31 and the transition portion 1222, reducing the heat generation of the battery cell 100, and improving the fast charging performance of the battery cell 100.

[0467] In some embodiments, L3 = L2. Along the second direction X, the ends of the second weld stamp 512 are flush with the ends of the transition portion 1222. In this embodiment of the present application, the second weld stamp 512 is larger along the second direction X, which facilitates designing a larger weld area between the second connecting sub-portion 312 and the transition portion 1222. This maximizes the current flow capacity at the connection between the second connecting sub-portion 312 and the transition portion 1222, effectively improving the current flow capacity of the first electrode sheet 1, reducing heat generation in the battery cell 100, and enhancing the fast charging performance of the battery cell 100.

[0468] In other embodiments, L3 < L2. Optionally, the second weld stamp 512 may be located in the middle of the transition portion 1222, with both ends of the second weld stamp 512 not flush with the transition portion 1222. Alternatively, along the second direction X, the second weld stamp 512 may be disposed toward one end of the transition portion 1222, such that one end of the second weld stamp 512 is flush with one end of the transition portion 1222, and the other end of the second weld stamp 512 is flush with the other end of the transition portion 1222.

[0469] In some embodiments, the protrusion 1221 and the transition portion 1222 are welded to the first connection portion 31 at the same time to form the entire first weld mark 51, which can effectively increase the welding area between the first connection portion 31 and the second metal portion 122, increase the flow area between the first connection portion 31 and the second metal portion 122, and help improve the flow capacity between the first connection portion 31 and the second metal portion 122.

[0470] In the process of cutting the conductive member 30, cutting is first performed along the second direction X on the equal-width weld mark, 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 along the second direction X, and then cutting is continued in the direction toward the active material layer 20 until cutting the equal-width weld mark for a distance, and then cutting is continued along the second direction X on the equal-width weld mark. This cycle is repeated to obtain the first weld mark 51. Taking the cutting position along the second direction X on the uniform width weld mark as a reference, along the first direction Z, the portion of the first weld mark 51 located at the cutting position facing the active material layer 20 is the second weld mark portion 512, and the portion located at the cutting position facing away from the active material layer 20 is the first weld mark portion 511. The first weld mark portion 511 can be a protruding structure with the second weld mark portion 512 facing away from the active material layer 20. During the cutting process, the metal layer 12 of the current collector 10 is cut into a protruding portion 1221, and a transition portion 1222 is formed between the protruding portion 1221 and the first metal portion 121.

[0471] In some embodiments, the second weld stamp 512 and the first weld stamp 511 are directly connected.

[0472] In some examples, the second weld print portion 512 and the first weld print portion 511 form a whole first weld print 51, and there is no obvious dividing line between the two; the whole first weld print 51 can cover the junction of the protrusion 1221 and the transition portion 1222; in the actual manufacturing process, the second weld print portion 512 and the first weld print portion 511 are formed by cutting using the above-mentioned equal-width weld prints.

[0473] In some examples, the second weld print 512 and the first weld print 511 adopt a weld point structure, and the spacing between the weld points in the second weld print 512 is the same as the spacing between the weld points in the first weld print 511; for example: the weld points in the second weld print 512 and the first weld print 511 are not welded to the boundary line between the protrusion 1221 and the transition portion 1222, and the spacing between two adjacent weld points in the second weld print 512 and the first weld print 511 is equal to the spacing between the weld points in the second weld print 512; for example, the weld points are welded to the boundary line between the protrusion 1221 and the transition portion 1222, thereby connecting the second weld print 512 and the first weld print 511 into a whole weld print.

[0474] By adopting the technical solution of this embodiment, the first weld mark 51 can cover the junction of the protrusion 1221 and the transition portion 1222. When a part of the current flows to the junction of the transition portion 1222 and the protrusion 1221, it can directly flow through the first weld mark 51 to the first connecting portion 31, thereby reducing the overflow pressure at the junction of the protrusion 1221 and the transition portion 1222, which is beneficial to improving the overflow 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.

[0475] In some embodiments, an end surface of the second connecting sub-portion 312 away from the active material layer 20 is flush with an end surface of the transition portion 1222 away from the first metal portion 121 .

[0476] The embodiment of the present application can reduce the redundancy of the second connecting sub-portion 312 or the redundancy of the transition portion 1222 , save materials, improve space utilization, and enhance the energy density of the battery cell 100 .

[0477] In addition, the first insulating component 4 can simultaneously block the burrs on the end face of the second connecting sub-part 312 away from the active material layer 20 and the burrs on the end face of the transition part 1222 away from the first metal part 121, reducing the risk of burrs piercing the isolation member 3 and improving reliability.

[0478] In some embodiments, there are multiple protrusions 1221, and the multiple protrusions 1221 are spaced apart along the second direction X. The first connecting portion 31 includes a second connecting sub-portion 312 and multiple first connecting sub-portions 311. The multiple first connecting sub-portions 311 are spaced apart along the second direction X, and each first connecting sub-portion 311 is welded to each protrusion 1221 in a one-to-one correspondence to form a first welded portion 511. The second connecting sub-portions 312 are continuously arranged along the second direction X and welded to the transition portion 1222 to form a second welded portion 512. The first welded portion 51 includes a second welded portion 512 and multiple first welded portions 511.

[0479] As an example, the first connecting sub-portion 311 may refer to the portion of the first connecting portion 31 covering the protruding portion 1221 ; the second connecting sub-portion 312 may refer to the portion of the first connecting portion 31 covering the transition portion 1222 .

[0480] As an example, the second connecting sub-portions 312 are continuously arranged along the second direction X. Optionally, along the second direction X, the second connecting sub-portions 312 extend from one side of the transition portion 1222 to the other side of the transition portion 1222 .

[0481] The plurality of first connecting sub-portions 311 of the first connecting portion 31 are spaced apart along the second direction X, with a gap between two adjacent first connecting sub-portions 311 . This can reduce the material required for the first connecting portion 31 , lower the manufacturing cost of the battery cell 100 , and improve the energy density of the battery cell 100 .

[0482] The second connecting sub-portions 312 are continuously arranged along the second direction X, and multiple first connecting sub-portions 311 can be connected into a whole. The second connecting sub-portions 312 can provide good support for the first connecting sub-portions 311, reduce the risk of the first connecting sub-portion 311 being inserted between the active material layer 20 and the second pole piece 2 when being bent, reduce the risk of short circuit, and help improve the reliability of the battery cell 100; in addition, along the second direction X, 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 1222, improving the flow capacity at the connection between the first connecting portion 31 and the transition portion 1222, improving the flow capacity of the first pole piece 1, and improving the fast charging performance and reliability of the battery cell 100.

[0483] In some embodiments, there are multiple second connection parts 32 . Along the first direction Z, one end of the first connection sub-part 311 is connected to the corresponding second connection part 32 , and the other end of the first connection sub-part 311 is connected to the corresponding second connection sub-part 312 .

[0484] In some embodiments, the sum of the dimensions L4 of all the first weld prints 511 is smaller than the dimension L3 of the second weld print 512. The larger dimension L3 of the second weld print 512 is beneficial to increasing the welding area between the transition portion 1222 and the second connecting sub-portion 312, and is beneficial to improving the flow capacity at the connection between the transition portion 1222 and the conductive component 30, and is beneficial to 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 and reliability of the battery cell 100.

[0485] Among the plurality of first weld prints 511 , along the second direction X, some of the first weld prints 511 may have the same size, all of the first weld prints 511 may have completely different sizes, or all of the first weld prints 511 may have the same size.

[0486] In some embodiments, the number of metal layers 12 is two, and the two metal layers 12 are arranged on opposite sides of the insulating base 11 along the thickness direction Y of the current collector. The number of active material layers 20 is two, and the two active material layers 20 are respectively covered on the two metal layers 12; the number of conductive components 30 is two, and the first connecting portions 31 of the two conductive components 30 are respectively welded to the surfaces of the two metal layers 12 facing away from the insulating base 11 and form two first weld marks 51; the number of first insulating components 4 is two, and the two first insulating components 4 respectively cover at least part of the two first weld marks 51.

[0487] The number of metal layers 12, the number of first insulating components 4, 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 Y, 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 portion 31 of one conductive component 30 is welded to the surface 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 portion 31 of the other conductive component 30 is welded to the other metal layer 12 and also forms a first weld mark 51. The two first insulating components 4 are located on the opposite sides of the insulating base 11 along the thickness direction Y and respectively cover the two first weld marks 51.

[0488] In some embodiments, along the direction from the first metal portion 121 to the transition portion 1222 , the first insulating component 4 protrudes from an end portion of the transition portion 1222 facing away from the first metal portion 121 .

[0489] In some embodiments, the first insulating component 4 at least partially covers the end surface of the transition portion 1222 away from the first metal portion 121. Alternatively, the first insulating component 4 completely covers the end surface of the transition portion 1222 away from the first metal portion 121. Along the thickness direction Y of the current collector, the projection of the end surface of the transition portion 1222 facing away from the first metal portion 121 coincides with the projection of the first insulating component 4.

[0490] For example, during the cutting process of the conductive member 30, burrs are likely to form on the end surface of the transition portion 1222 facing the protrusion 1221. In particular, during the cutting process of the conductive member 30 at the first weld mark 51, larger burrs are likely to form on the end surface of the transition portion 1222 facing the protrusion 1221. The first insulating component 4 of the embodiment of the present application can block burrs on the end surface of the transition portion 1222 facing the protrusion 1221, reducing the risk of burrs piercing the separator 3 and contacting the second electrode sheet 2, thereby reducing the risk of short circuits in the battery cell 100 and improving the reliability of the battery cell 100.

[0491] In some examples, the end surface of the transition portion 1222 facing the protrusion 1221 is susceptible to impact, generating metal debris. The metal debris may fall into the electrode assembly 101, causing a short circuit in the battery cell 100. The third insulator portions 43 of the two first insulating components 4 are arranged in close contact. The two third insulator portions 43 can block the metal debris, reducing the risk of metal debris falling into the electrode assembly 101, thereby reducing the risk of short circuits.

[0492] In some embodiments, the first weld mark 51 may include only a first weld mark portion 511; illustratively, in the first direction Z, the distance between the first weld mark portion 511 and the active material layer 20 is 0.3 mm to 5 mm. In other embodiments, the first weld mark 51 may include a second weld mark portion 512; in the first direction Z, the distance between the second weld mark portion 512 and the active material layer 20 is 0.3 mm to 5 mm.

[0493] In some embodiments, the electrode assembly 101 further includes a second electrode piece 2 having opposite polarity to the first electrode piece 1 . The second electrode piece 2 includes a main functional portion 210 and a pole ear portion 220 . The pole ear portion 220 extends from the end surface of the main functional portion 210 along the first direction Z.

[0494] The second electrode 2 may be an electrode with opposite polarity to the first electrode 1. For example, the first electrode 1 is a positive electrode and the second electrode 2 is a negative electrode, or the first electrode 1 is a negative electrode and the second electrode 2 is a positive electrode.

[0495] The first electrode sheet 1 and the second electrode sheet 2 may be stacked and then wound to form a wound electrode assembly 101 ; alternatively, a plurality of first electrode sheets 1 and a plurality of second electrode sheets 2 may be stacked to form a laminated electrode assembly 101 .

[0496] The second pole piece 2 includes a main functional portion 210 and a tab portion 220. The main functional portion 210 may refer to the main portion of the second pole piece 2, and the tab portion 220 may refer to the portion of the second pole piece 2 that protrudes from the main functional portion 210. For example, when the second pole piece 2 is a negative pole piece, the tab portion 220 may refer to a protruding structure located at the edge of the negative electrode current collector, and the main functional portion 210 may include the portion of the negative electrode current collector excluding the protruding structure and the negative electrode active material layer. For example, when the second pole piece 2 is a positive pole piece, the tab portion 220 may refer to a protruding structure located at the edge of the positive electrode current collector, and the main functional portion 210 may include the portion of the positive electrode current collector excluding the protruding structure and the positive electrode active material layer.

[0497] In some embodiments, along the direction from the active material layer 20 to the first connecting portion 31 , the end surface of the second connecting sub-portion 312 facing away from the active material layer 20 extends beyond the main functional portion 210 .

[0498] Even if a burr on the end surface of the second connector 312 facing away from the active material layer 20 pierces the separator 3 , the burr is unlikely to come into contact with the main functional portion 210 , thereby reducing the risk of short circuit.

[0499] In some embodiments, along the direction from the active material layer 20 to the first connection portion 31 , the end surface of the main functional portion 210 facing the electrode tab portion 220 extends beyond the first end surface 31 a .

[0500] The main body functional portion 210 can extend beyond the first end surface 31 a , so that the main body functional portion 210 can have a larger size in the first direction Z, thereby increasing the capacity of the main body functional portion 210 .

[0501] In some embodiments, the first insulating component 4 separates the first end surface 31a from the main functional portion 210, thereby blocking the burrs at the first end surface 31a, reducing the possibility of the burrs at the first end surface 31a overlapping with the main functional portion 210, reducing the risk of short circuit, and improving the reliability of the battery cell 100.

[0502] In some embodiments, along the direction from the active material layer 20 to the first connection portion 31 , the first insulating component 4 extends beyond the end surface of the main functional portion 210 toward the electrode tab portion 220 .

[0503] For example, along the thickness direction Y of the current collector, the projection of the end surface of the main functional portion 210 close to the electrode tab portion 220 falls within the projection of the first insulating component 4 .

[0504] The first insulating component 4 can prevent burrs on the end surface of the main functional part 210 of the second pole piece 2 near the pole ear part 220 from piercing the isolation member 3 and connecting with the first pole piece 1, reducing the risk of short circuit between the first pole piece 1 and the second pole piece 2, which is beneficial to improving the reliability of the battery cell 100.

[0505] In some embodiments, along the direction of the active material layer 20 pointing to the first connecting portion 31, the end face of the main functional portion 210 toward the pole ear portion 220 may extend beyond the end face of the second connecting sub-portion 312 facing away from the active material layer 20, or may not extend beyond the end face of the second connecting sub-portion 312 facing away from the active material layer 20.

[0506] As an example, in Figure 6 In FIG, a connection point between the first connection sub-portion 311 and the second connection sub-portion 312 is indicated by a dotted line D7 , and a connection point between the first connection sub-portion 311 and the second connection portion 32 is indicated by a dotted line D8 .

[0507] Optionally, along the direction from the active material layer 20 to the first connecting portion 31, the end surface of the main functional portion 210 facing the pole ear portion 220 does not extend beyond the end surface of the second connecting sub-portion 312 facing away from the active material layer 20. Along the thickness direction Y of the current collector, the projection of the end surface of the main functional portion 210 facing the pole ear portion 220 at least partially overlaps with the projection of the second connecting sub-portion 312. The burr on the end surface of the main functional portion 210 of the second pole piece 2 facing the pole ear portion 220 faces the first insulating component 4.

[0508] Alternatively, along the direction from the active material layer 20 to the first connecting portion 31, the end surface of the main functional portion 210 facing the pole lug 220 extends beyond the end surface of the second connecting sub-portion 312 facing away from the active material layer 20. Along the thickness direction Y of the current collector, the projection of the end surface of the main functional portion 210 facing the pole lug 220 does not overlap with the projection of the second connecting sub-portion 312. This allows the burrs on the end surface of the main functional portion 210 of the second pole piece 2 facing the pole lug 220 to correspond to the hollowed-out area of the second metal portion 122 where the protrusion 1221 does not extend. This can also reduce the risk of short circuits in the battery cell 100 and improve the reliability of the battery cell 100.

[0509] In some embodiments, along the thickness direction Y of the current collector, the projection of the second weld print 512 may fall within the projection of the main functional part 210, and the second weld print 512 may be covered with the first insulating component 4, so that the first insulating component 4 can block burrs, metal debris and other components on the second weld print 512, reducing the risk of burrs, metal debris and other components piercing the isolation part 3 and connecting with the second pole piece 2, reducing the risk of short circuit, and improving the reliability of the battery cell 100.

[0510] In some embodiments, along the direction from the active material layer 20 toward the first connection portion 31 , the main functional portion 210 protrudes from the end surface of the first insulating component 4 close to the active material layer 20 , and the main functional portion 210 does not protrude from the end surface of the first insulating component 4 away from the active material layer 20 .

[0511] Figure 18 Schematic partial cross-sectional views of electrode assemblies of battery cells provided in some other embodiments of the present application.

[0512] Reference Figure 18 In some embodiments, the electrode assembly 101 includes a second insulating component 6 , which is disposed on a surface of the metal layer 12 facing away from the insulating substrate 11 . In the first direction Z, at least a portion of the second insulating component 6 is located between the first connecting portion 31 and the active material layer 20 .

[0513] The second insulating component 6 may be, but is not limited to, an insulating coating, an insulating adhesive (eg, hot melt adhesive, etc.), or an insulating tape.

[0514] In some examples, in the first direction Z, the second insulating component 6 can be located entirely between the first connecting portion 31 and the active material layer 20; alternatively, a portion of the second insulating component 6 is located between the first connecting portion 31 and the active material layer 20 in the first direction Z, and another portion covers the first connecting portion 31 or the active material layer 20.

[0515] The second insulating component 6 can support the portion of the metal layer 12 located between the first connecting portion 31 and the active material layer 20, thereby reducing damage such as cracks and fractures that occur in this portion during the manufacturing process of the battery device 1100, which is beneficial to improving the electron transmission capability of this portion of the metal layer 12 and improving the fast charging performance and reliability of the battery cell 100; in addition, the second insulating component 6 can also separate the area of the metal layer 12 that is not covered by the first connecting portion 31 and the active material layer 20 from the second electrode 2, thereby reducing the risk of short circuit and improving the reliability of the battery cell 100.

[0516] In some embodiments, along the thickness direction Y of the current collector, the second insulating component 6 does not overlap with the first weld mark 51. The second insulating component 6 is spaced apart from the first weld mark 51, so that the first connection portion 31 is not welded to the second insulating component 6, which helps reduce the risk of a cold weld between the first connection portion 31 and the metal layer 12. In other embodiments, the second insulating component 6 and the first weld mark 51 only overlap at their edges, and the edge of the first weld mark 51 overlaps with the edge of the second insulating component 6, which can also reduce the risk of a cold weld between the first connection portion 31 and the metal layer 12.

[0517] By adopting the technical solution of this embodiment, the risk of cold soldering between the first connecting portion 31 and the metal layer 12 is reduced, the connection reliability between the first connecting portion 31 and the metal layer 12 is improved, and the current carrying capacity is enhanced.

[0518] In some embodiments, in the first direction Z, the entire second insulating component 6 is located between the first connecting portion 31 and the active material layer 20 .

[0519] In some embodiments, a portion of the first insulating component 4 is located on a side of the second insulating component 6 facing away from the metal layer 12 and is connected to the second insulating component 6 .

[0520] The first insulating member 4 may cover a portion of the second insulating member 6 or may completely cover the second insulating member 6. For example, one end of the second insulating member 6 along the first direction Z extends to the active material layer 20, thereby completely covering the second insulating member 6.

[0521] As an example, the portion of the first insulating component 4 covering the second insulating component 6 is connected to the portion of the first insulating component 4 covering the first connecting portion 31 .

[0522] Connecting the first insulating component 4 to the second insulating component 6 can reduce the risk of the first insulating component 4 falling off. The first insulating component 4 and the second insulating component 6 can jointly cover the metal layer 12, thereby improving the insulation effect, reducing the risk of the metal layer 12 and the second electrode 2 being conductive, and improving reliability.

[0523] In some embodiments, two ends of the second insulating component 6 along the first direction Z are connected to the active material layer 20 and the first connecting portion 31 , respectively.

[0524] In some embodiments, a portion of the first insulating member 4 covers the first connecting portion 31, and another portion of the first insulating member 4 covers the active material layer 20. The first insulating member 4 is continuously disposed along the first direction Z and covers the portion of the metal layer 12 between the first connecting portion 31 and the active material layer 20.

[0525] A second insulating component 6 may or may not be provided between the first insulating component 4 and the metal layer 12 .

[0526] In some examples, the metal layer 12 is covered with the second insulating component 6. After the first insulating component 4 completely covers the second insulating component 6, it can also extend onto the active material layer 20 to cover a portion of the active material layer 20. The metal layer 12 is covered with the second insulating component 6 and the first insulating component 4, achieving two layers of insulation and a good insulation effect.

[0527] In some examples, the metal layer 12 is not covered with the second insulating component 6, and the first insulating component 4 extends from the first connecting portion 31 to the active material layer 20, so that the portion of the metal layer 12 located between the first connecting portion 31 and the active material layer 20 can be covered, reducing the risk of short circuit in this portion, which is beneficial to improving the reliability of the battery cell 100. In addition, the second insulating component 6 can be omitted to save costs. At the same time, the active material layer 20 can be used to cover the position of the original second insulating component 6, which can increase the coverage area of the active material layer 20 on the metal layer 12, which is beneficial to improving the energy density of the battery cell 100.

[0528] The first insulating component 4 extends from the first connecting portion 31 to the active material layer 20 . The first insulating component 4 has a wide coverage area and a good insulating effect, which is beneficial to improving the reliability of the battery cell 100 .

[0529] In some embodiments, the second insulating component 6 is connected to the end surface of the active material layer 20 facing the first connection portion 31. The second insulating component 6 and the active material layer 20 form a mutually dissolving zone, so that the second insulating component 6 is fixed more stably.

[0530] In some embodiments, the second insulating member 6 and the active material layer 20 face a portion of the first connecting portion 31 .

[0531] In some embodiments, the second insulating component 6 is provided at the transition portion. Optionally, the second insulating component 6 is coated at the transition portion.

[0532] Figure 19 Schematic diagram of a first pole piece, a first insulating component, and a second insulating component of a battery cell in an unfolded state provided by some other embodiments of the present application; Figure 20 for Figure 19 Schematic cross-section along line DD; Figure 21 for Figure 19 A schematic diagram of the first pole piece and the second insulating component shown; Figure 22 for Figure 21 An enlarged schematic diagram at the circle;

[0533] Figure 23 for Figure 21 A schematic diagram of a first pole piece is shown, wherein the conductive member is shown; Figure 24 for Figure 23 An enlarged schematic diagram at the circle; Figure 25 for Figure 19 A schematic diagram of the first insulating component shown; Figure 26 for Figure 25 An enlarged schematic diagram at the circle; Figure 27 for Figure 21 A schematic diagram of a portion of a conductive member is shown.

[0534] Reference Figures 19 to 27 In some embodiments, the second metal portion 122 includes at least one protrusion 1221; the first connecting portion 31 includes at least one first connecting sub-portion 311, and the first connecting sub-portion 311 is located on the side of the protrusion 1221 away from the insulating base 11, and the first connecting sub-portion 311 corresponds one-to-one to the protrusion 1221.

[0535] Alternatively, the first connection portion 31 may include only the first connection sub-portion 311 overlapping the protrusion 1221. In other words, the first connection portion 31 may not include the second connection sub-portion 312. The second metal portion 122 may include the transition portion 1222 or not.

[0536] In some embodiments, the second metal portion 122 includes a protruding portion 1221 , and the first connecting portion 31 includes a first connecting sub-portion 311 . The end surface of the first connecting sub-portion 311 facing the active material layer 20 is the first end surface 31 a .

[0537] In some embodiments, the second metal portion 122 includes a plurality of protrusions 1221, and the first connecting portion 31 includes a plurality of first connecting sub-portions 311. The plurality of first connecting sub-portions 311 are disposed in a one-to-one correspondence with the plurality of protrusions 1221. Each first connecting sub-portion 311 has a second end surface 31b at one end facing the active material layer 20; the second end surfaces 31b of the plurality of first connecting sub-portions 311 form the first end surface 31a.

[0538] The first insulating component 4 can block the burrs on each second end surface 31 b, reducing the possibility that the burrs on the second end surface 31 b pierce the isolation member 3 and contact the second pole piece 2, thereby reducing the risk of short circuit.

[0539] In some embodiments, the conductive member 30 includes a plurality of second connecting portions 32. Each first connecting portion 311 is connected to each second connecting portion 32 in a one-to-one correspondence. Exemplarily, one first connecting portion 31 and one second connecting portion 32 constitute a conductive sheet, and the conductive member 30 includes a plurality of conductive sheets arranged along the second direction X. Exemplarily, the plurality of conductive sheets of the two conductive members 30 are arranged in a one-to-one correspondence. Exemplarily, in Figure 17 In the figure, the boundary between the first connecting sub-portion 311 and the second connecting portion 32 is shown by a dotted line. The boundary between the first connecting sub-portion 311 and the second connecting portion 32 corresponds to the end surface of the protrusion 1221 facing away from the transition portion.

[0540] In some embodiments, the first connecting portion 311 only covers a portion of the protruding portion 1221. For example, along the direction from the first connecting portion 31 to the active material layer 20, the protruding portion 1221 protrudes from the second end surface 31b.

[0541] In some embodiments, the first insulating component 4 covers the portion of the protrusion 1221 that is not covered by the first connecting sub-portion 311 .

[0542] In some embodiments, the electrode assembly 101 includes a second insulating member 6, at least a portion of which is disposed on the protrusion 1221 and located between the first connecting sub-portion 311 and the active material layer 20. Alternatively, the second insulating member 6 may be omitted, with a portion of the first insulating member 4 attached to the first connecting sub-portion 311 and another portion of the first insulating member 4 attached to the protrusion 1221.

[0543] In some embodiments, the first insulating component 4 completely covers the first connecting sub-portion 311 .

[0544] In some embodiments, the first insulating component 4 completely covers the protrusion 1221 .

[0545] In some embodiments, the second metal portion 122 further includes a transition portion 1222 , and the transition portion 1222 is connected between the first metal portion 121 and the protruding portion 1221 .

[0546] In some embodiments, the first insulating component 4 covers at least a portion of the transition portion 1222 .

[0547] In some embodiments, along the direction from the first metal portion 121 to the transition portion 1222, the first insulating component 4 protrudes from the end surface of the transition portion 1222 facing away from the first metal portion 121. The first insulating component 4 can block burrs on the end surface of the transition portion 1222, reducing the risk of burrs piercing the separator 3 and contacting the second pole piece 2, thereby reducing the risk of short circuits and improving reliability.

[0548] In some embodiments, the first insulating component 4 completely covers the transition portion 1222 .

[0549] In some embodiments, the electrode assembly 101 includes a second insulating member 6 , at least a portion of which is coated on the transition portion 1222 .

[0550] Optionally, the first insulating component 4 covers the second insulating component 6 .

[0551] In some embodiments, the first insulating component 4 includes a first insulator portion 41 , a second insulator portion 42 , a third insulator portion 43 , and a fourth insulator portion 44 .

[0552] The first insulator portion 41 covers the surface of the first connector portion 311 facing away from the protrusion 1221 . The second insulator portion 42 is connected to the first insulator portion 41 and is located on the side of the first insulator portion 41 facing the active material layer 20 along the first direction Z.

[0553] The third insulator portion 43 and the first insulator portion 41 are arranged along the second direction X. In the first direction Z, the third insulator portion 43 and the first insulator portion 41 are located on the same side of the second insulator portion 42. The end of the third insulator portion 43 along the first direction Z is connected to the second insulator portion 42, and the end of the third insulator portion 43 along the second direction X is connected to the first insulator portion 41.

[0554] The fourth insulator portion 44 is connected to the first insulator portion 41 , and the second insulator portion 42 is located on a side of the first insulator portion 41 facing away from the active material layer 20 along the first direction Z. Optionally, the fourth insulator portion 44 is attached to the second connecting portion 32 and connected to the third insulator portion 43 .

[0555] As an example, see Figure 25 and Figure 26 The boundaries of the first insulating portion, the second insulating portion, the third insulating portion and the fourth insulating portion are indicated by dashed lines D9 and D 10 、D 11 、D 12 、D 13 、D 14 Among them, the dotted line D9 corresponds to the second end face 31b (the intersection of the plane where the second end face 31b is located and the first insulating component 4 is the dotted line D9), and the dotted line D 10 Corresponding to the junction of the first connecting portion 31 and the second connecting portion 32 (the junction of the first connecting portion 31 and the second connecting portion 32 corresponds to the end surface of the protrusion 1221 facing away from the transition portion 1222), D 11 and D 12 respectively corresponding to the two ends of the first connecting sub-portion 311 along the second direction X, D 13 and D 14 They correspond to two ends of the second connection portion 32 along the second direction X respectively.

[0556] In some embodiments, both the third insulator portion 43 and the first insulator portion 41 are plural, and the plurality of third insulator portions 43 and the plurality of first insulator portions 41 are alternately arranged along the second direction X.

[0557] In some embodiments, the third insulator portion 43 can block burrs on the end of the first connecting portion 311 along the second direction X and burrs on the second connecting portion 32 along the second direction X.

[0558] In some embodiments, along the direction of the transition portion 1222 pointing toward the first metal portion 121, the second insulator portion 42 protrudes from the end surface of the transition portion 1222 facing the protruding portion 1221. The second insulator portion 42 can block burrs on the end surface of the transition portion 1222 facing the protruding portion 1221.

[0559] In some embodiments, along the second direction X, two ends of the second insulator portion 42 protrude from two ends of the transition portion 1222 .

[0560] In some embodiments, the protrusion 1221 includes a first protrusion sub-portion 1221a and a second protrusion sub-portion 1221b, wherein the first protrusion sub-portion 1221a is connected between the second protrusion sub-portion 1221b and the first metal portion 121. Along the second direction X, a dimension l1 of the first protrusion sub-portion 1221a is greater than a dimension l2 of the second protrusion sub-portion 1221b.

[0561] For example, the protrusion 1221 has a stepped structure. Along the first direction Z, the protrusion 1221 is divided into two parts, the part close to the first metal part 121 is the first protruding sub-part 1221a, and the part away from the first metal part 121 is the second protruding sub-part 1221b; along the second direction X, the size of the first protruding sub-part 1221a is larger than the size of the second protruding sub-part 1221b, which is equivalent to increasing the size of the first protruding sub-part 1221a along the second direction X, increasing the flow area between the protrusion 1221 and the first metal part 121, improving the flow capacity, and reducing the heat generation of the battery cell 100.

[0562] The first protruding portion 1221a may refer to the root of the protruding portion 1221 close to the transition portion 1222; for example, along the second direction X, the dimension l1 of the first protruding portion 1221a may refer to the boundary line between the protruding portion 1221 and the transition portion 1222 (see the dotted line D 15 The length l1 of each first protruding sub-portion 1221a along the second direction X may be the same or different.

[0563] Along the second direction X, the dimension l2 of the second protruding sub-portion 1221b is equal to the boundary line between the first protruding sub-portion 1221a and the second protruding sub-portion 1221b (see the dotted line D 16 The length l2 of each second protruding sub-portion 1221b along the second direction X may be the same or different.

[0564] l1>l2, which is equivalent to increasing the size of the first protruding sub-portion 1221a along the second direction X, increasing the flow area between the protruding portion 1221 and the transition portion 1222, improving the flow capacity, and reducing the heat generation of the battery cell 100.

[0565] In some embodiments, the first connecting sub-portion 311 includes a first connecting protrusion 3111 , and the first connecting protrusion 3111 is located on a side of the first protruding sub-portion 1221 a facing away from the insulating base 11 .

[0566] The first insulating component 4 includes at least one first insulator portion 41, which corresponds one-to-one with the first connecting portion 311. At least a portion of the first insulator portion 41 covers the first connecting protrusion 3111. The first insulator portion 41 covers the first connecting protrusion 3111, reducing the risk of contact and conduction between the first connecting protrusion 3111 and the second pole piece 2.

[0567] In some embodiments, the first connecting protrusion 3111 is welded to the surface of the first protruding sub-portion 1221 a facing away from the insulating base 11 to form a first weld sub-portion 5111 . The first weld sub-portion 5111 includes a first weld sub-portion 5111 .

[0568] Exemplarily, the first connecting protrusion 3111 is welded to the surface of the first protruding sub-portion 1221 a facing away from the insulating base 11 , and a trace produced by the welding may be the first weld mark sub-portion 5111 .

[0569] For example, the first connecting protrusion 3111 can be welded to the first protruding sub-portion 1221a to reduce the distance between the first weld sub-portion 5111 and the transition portion 1222, which is beneficial to improving the current flow capacity between the first connecting portion 31 and the transition portion 1222, reducing the heat generation of the battery cell 100, and improving the fast charging performance and usage reliability of the battery cell 100.

[0570] In some embodiments, the first insulator portion 41 covers at least a portion of the first weld sub-portion 5111. The first insulator portion 41 may cover a portion of the first weld sub-portion 5111 or the entire first weld sub-portion 5111.

[0571] The first connecting protrusion 3111 is welded to the first protruding sub-portion 1221a to form a first weld sub-portion 5111. The large dimension of the first protruding sub-portion 1221a along the second direction X increases the welding area between the protruding portion 1221 and the first connecting sub-portion 311, thereby improving the flow area between the protruding portion 1221 and the first connecting sub-portion 311, enhancing the flow capacity, reducing heat generation in the battery cell 100, and facilitating improved fast charging performance and reliability of the battery cell 100. Furthermore, the small dimension of the second protruding sub-portion 1221b along the second direction X reduces the space occupied by the protruding portion 1221 and improves the energy density of the battery cell 100. The first insulating component 4 can block burrs, metal debris, and other components on the first weld sub-portion 5111, reducing the risk of burrs, metal debris, and other components passing through the separator 3 and contacting the second electrode 2, thereby improving the reliability of the battery cell 100.

[0572] In some embodiments, along the second direction X, the sum l3 of the sizes of the first protruding sub-portions 1221 a of all the protruding portions 1221 is greater than or equal to 0.5 times the size L1 of the first metal portion 121 . Exemplarily, 0.5≤l3 / L1≤1.

[0573] Along the second direction X, the sum of the sizes l3 of the first protruding sub-portions 1221a of all the protrusions 1221 is greater than or equal to more than half of the size L1 of the first metal portion 121, thereby increasing the total flow area between the protrusion 1221 and the first metal portion 121 and improving the total flow capacity between the protrusion 1221 and the first metal portion 121; for example, the sum of the sizes l3 of the first protruding sub-portions 1221a of all the protrusions 1221 along the second direction X can be increased by increasing the number of protrusions 1221, or the sum of the sizes l3 of the first protruding sub-portions 1221a of all the protrusions 1221 along the second direction X can be increased by increasing the size of a single first protruding sub-portion 1221a along the second direction X.

[0574] In some examples, the value of l3 / L1 may be 0.5 and any value between 0.5-1, for example; wherein the value of l3 / L1 may be, but is not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99.

[0575] In some embodiments, along the direction from the first metal portion 121 to the protruding portion 1221 , the first insulating component 4 protrudes from the end surface of the first protruding sub-portion 1221 a facing away from the first metal portion 121 .

[0576] Along the thickness direction Y of the current collector, the projection of the end surface of the first protruding sub-portion 1221 a facing away from the first metal portion 121 falls within the projection of the first insulating component 4 .

[0577] During the production process of the electrode, the end face of the first protruding sub-portion 1221a facing away from the first metal portion 121 is obtained by cutting, which makes it easy for burrs to form on the end face of the first protruding sub-portion 1221a facing away from the first metal portion 121. The first insulating component 4 can block the burrs at the end face of the first protruding sub-portion 1221a facing away from the first metal portion 121, thereby reducing the risk of short circuit inside the battery cell 100 and helping to improve the reliability of the battery cell 100. In addition, the first insulating component 4 can completely cover the first weld mark sub-portion 5111, thereby reducing the risk of short circuit caused by burrs, metal debris and other components on the first weld mark sub-portion 5111, thereby helping to improve the reliability of the battery cell 100.

[0578] In some embodiments, along the second direction X, the first weld sub-portion 5111 extends from one side of the first protruding sub-portion 1221 a to the other side of the first protruding sub-portion 1221 a.

[0579] Along the thickness direction Y, the projection of the first weld sub-portion 5111 falls within the projection of the first protruding sub-portion 1221 a.

[0580] The first weld sub-portion 5111 has a large size along the second direction X, which is beneficial to increasing the welding area between the protrusion 1221 and the first connecting portion 31, increasing the flow area between the protrusion 1221 and the first metal portion 121, improving the flow capacity, reducing the heat generation of the battery cell 100, and being beneficial to improving the fast charging performance and reliability of the battery cell 100.

[0581] In some embodiments, the first connecting sub-portion 311 includes a second connecting protrusion 3112 located on a side of the second protruding sub-portion 1221b facing away from the insulating base 11. Along the second direction X, the first connecting protrusion 3111 is larger than the second connecting protrusion 3112.

[0582] As an example, the junction between the second connecting protrusion 3112 and the first connecting protrusion 3111 corresponds to the junction between the first protruding sub-portion 1221a and the second protruding sub-portion 1221b. Figure 27 In FIG, the boundary between the second connecting protrusion 3112 and the first connecting protrusion 3111 is indicated by a dotted line D 17 The junction of the second connecting protrusion 3112 and the second connecting portion 32 is indicated by a dotted line D 18 Shown.

[0583] The first insulator portion 41 covers the first connecting protrusion 3111 and the second connecting protrusion 3112. The first insulator portion 41 can cover the first connecting protrusion 3111 and the second connecting protrusion 3112, reducing the risk of the first connecting sub-portion 311 and the second pole piece 2 contacting and conducting.

[0584] In some embodiments, the first weld portion 511 further includes a second weld sub-portion 5112, the second connecting protrusion 3112 is welded to the surface of the second protruding sub-portion 1221b facing away from the insulating base 11 to form the second weld sub-portion 5112, and the first insulating component 4 covers at least a portion of the second weld sub-portion 5112.

[0585] For example, the surface of the second protruding portion 1221 b facing away from the insulating base 11 is welded to the second connecting protrusion 3112 , and a trace of the welding is the second weld mark 5112 .

[0586] The first insulator portion 41 may cover a portion of the second weld portion 5112 , or may cover the entire second weld portion 5112 .

[0587] The second protruding sub-portion 1221b is also welded to the first connecting sub-portion 311, which helps increase the flow area between the first connecting sub-portion 311 and the protruding portion 1221, thereby improving the flow capacity between the first connecting sub-portion 311 and the protruding portion 1221. The first insulating component 4 can block burrs, metal debris, and other components on the second weld sub-portion 5112, reducing the risk of burrs, metal debris, and other components passing through the separator 3 and contacting the second pole piece 2, thereby improving the reliability of the battery cell 100.

[0588] In some embodiments, along the direction from the first metal portion 121 to the protruding portion 1221 , the first insulating component 4 protrudes from an edge of the second weld sub-portion 5112 facing away from the first protruding sub-portion 1221 a .

[0589] Along the thickness direction Y of the current collector, the projection of the edge of the second weld sub-portion 5112 facing away from the first protruding sub-portion 1221a falls within the projection of the first insulating component 4 , so that the first insulating component 4 can completely cover the second weld sub-portion 5112 and the first weld sub-portion 5111 .

[0590] The first insulating component 4 can completely cover the second weld mark portion 5112 and the first weld mark portion 5111 , reducing the risk of short circuit caused by burrs, metal debris and other components on the second weld mark portion 5112 and the first weld mark portion 5111 , which is beneficial to improving the reliability of the battery cell 100 .

[0591] In some embodiments, along the second direction X, the second weld sub-portion 5112 extends from one side of the second protruding sub-portion 1221 b to the other side of the second protruding sub-portion 1221 b.

[0592] Along the thickness direction Y, the projection of the second weld sub-portion 5112 falls within the projection of the second protruding sub-portion 1221b.

[0593] The second weld sub-portion 5112 has a large size along the second direction X, which is beneficial to increasing the welding area between the first connecting sub-portion 311 and the protruding portion 1221 , thereby improving the flow area and flow capacity between the first connecting sub-portion 311 and the protruding portion 1221 .

[0594] Figure 28 Schematic diagram of a first pole piece, a first insulating component, and a second insulating component of a battery cell in an unfolded state provided by some other embodiments of the present application; Figure 29 for Figure 28 Schematic diagram of the partial structure of the first insulating component shown.

[0595] Reference Figure 28 and Figure 29In some embodiments, the first insulating component 4 further includes a plurality of second insulator portions 42. The plurality of first insulator portions 41 and the plurality of second insulator portions 42 are provided in a one-to-one correspondence, with the first insulator portion 41 connected to the corresponding second insulator portion 42. In the first direction Z, the second insulator portion 42 is located on the side of the first insulator portion 41 facing the active material layer 20. Providing a plurality of second insulator portions 42 can reduce the size of a single second insulator portion 42, saving space and improving energy density.

[0596] In some embodiments, along the second direction X, a size of the second insulator portion 42 is greater than or equal to a size of the first insulator portion 41 .

[0597] In some embodiments, along the second direction X, two adjacent first insulator portions 41 are provided with two spaced-apart third insulator portions 43 .

[0598] The two third insulator sections 43 located between two adjacent first insulator sections 41 are respectively connected to the two first insulator sections 41. The first insulating component 4 forms a hollow area between the two third insulator sections 43, thereby saving weight and space occupied by the first insulating component 4 and improving energy density.

[0599] In some embodiments, the number of the third insulator portions 43 is twice the number of the first insulator portions 41 .

[0600] In some embodiments, the first insulating component 4 includes a plurality of insulating sheets 40, which are arranged in a one-to-one correspondence with the plurality of conductive sheets. The conductive sheet is composed of a first connecting sub-portion 311 and a second connecting portion 32, and the insulating sheet 40 is composed of a first insulator portion 41, a second insulator portion 42, two third insulator portions 43, and a fourth insulator portion 44.

[0601] As an example, in Figure 29 In FIG, the boundaries between the first insulating portion, the second insulating portion, the third insulating portion and the fourth insulating portion are indicated by dashed lines D9 and D 10 、D 11 、D 12 、D 13 、D 14 Wherein, the dotted line D9 corresponds to the second end face 31b (the intersection line of the plane where the second end face 31b is located and the first insulating component 4 can be the dotted line D9), and the dotted line D 10 Corresponding to the junction of the first connecting portion 31 and the second connecting portion 32 (the junction of the first connecting portion 31 and the second connecting portion 32 corresponds to the end surface of the protrusion 1221 facing away from the transition portion 1222), D 11 and D 12 respectively corresponding to the two ends of the first connecting sub-portion 311 along the second direction X, D 13and D 14 They correspond to two ends of the second connection portion 32 along the second direction X respectively.

[0602] In some embodiments, the insulating sheet 40 completely covers the corresponding conductive sheet.

[0603] In some embodiments, the insulating sheet 40 may be a rectangular tape.

[0604] Figure 30 Schematic diagram of a first pole piece and a first insulating component of a battery cell in an unfolded state provided by some other embodiments of the present application; Figure 31 for Figure 30 A schematic diagram of the first pole piece shown; Figure 32 for Figure 31 Another schematic diagram of the first pole piece is shown, in which the conductive component is omitted.

[0605] Reference Figures 30 to 32 In some embodiments, the second metal portion 122 includes a transition portion 1222 , and in the second direction X, both ends of the transition portion 1222 are flush with both ends of the first metal portion 121 , respectively. The second direction X is perpendicular to the first direction Z and the thickness direction Y of the current collector.

[0606] As an example, the second metal portion 122 may include a protrusion or may not include a protrusion.

[0607] Optionally, the second metal portion 122 does not include a protrusion.

[0608] The size of the transition portion 1222 along the second direction X is the same as the size of the first metal portion 121 along the second direction X. The current of the first metal portion 121 can be evenly transmitted to the transition portion 1222, thereby improving current consistency, enhancing overcurrent capability, and improving the fast charging performance of the battery cell 100.

[0609] In some embodiments, the first connecting portion 31 includes a second connecting sub-portion 312. The second connecting sub-portion 312 is located on the side of the transition portion 1222 facing away from the insulating substrate 11. The second connecting sub-portion 312 is welded to the surface of the transition portion 1222 facing away from the insulating substrate 11 to form a second weld mark 512. The first weld mark 51 includes the second weld mark 512. The end surface of the second connecting sub-portion 312 facing the active material layer 20 is the first end surface 31a.

[0610] During the cycle of the battery cell 100, current can be transmitted between the transition portion 1222 and the second connecting sub-portion 312, thereby improving the current carrying capacity, enhancing the fast charging performance and reliability of the battery cell 100. The first insulating component 4 can block burrs on the first end surface 31a, reducing the possibility of burrs piercing the separator 3 and contacting the second pole piece 2, thereby reducing the risk of short circuits.

[0611] In some embodiments, both ends of the first insulating component 4 protrude from the second connecting sub-portion 312 in the second direction X. The first insulating component 4 can block burrs at both ends of the second connecting sub-portion 312 along the second direction X, reducing the possibility of burrs piercing the separator 3 and contacting the second pole piece 2, thereby reducing the risk of short circuits.

[0612] In some embodiments, the first insulating component 4 completely covers the transition portion 1222 and the second connecting sub-portion 312 .

[0613] In some embodiments, the second connecting portion 32 is connected to an end of the second connecting sub-portion 312 facing away from the active material layer 20 .

[0614] In some embodiments, there are a plurality of second connecting portions 32 , and the second connecting sub-portion 312 extends continuously along the second direction X and is connected to the plurality of second connecting portions 32 .

[0615] In some embodiments, along the direction from the active material layer 20 to the first connecting portion 31 , the first insulating component 4 protrudes from the end surface of the second connecting sub-portion 312 facing away from the active material layer 20 .

[0616] In some embodiments, along the direction of the active material layer 20 pointing to the first connecting portion 31, the end surface of the second connecting sub-portion 312 facing away from the active material layer 20 may extend beyond the end surface of the transition portion 1222 facing away from the first metal portion 121, or may be flush with the end surface of the transition portion 1222 facing away from the first metal portion 121.

[0617] Figure 33 Schematic partial cross-sectional views of electrode assemblies of battery cells provided in some other embodiments of the present application.

[0618] Reference Figure 33 In some embodiments, the current collector 10 includes two metal layers 12, which are disposed on opposite sides of the insulating substrate 11 along the thickness direction Y of the current collector. The first pole piece 1 includes two active material layers 20 and two conductive members 30. The two active material layers 20 are respectively disposed on the two metal layers 12. The first connecting portions 31 of the two conductive members 30 are respectively welded to the second metal portions 122 of the two metal layers 12, forming two first weld marks 51. The second connecting portions 32 of the two conductive members 30 are welded to form second weld marks 52.

[0619] In some embodiments, the first insulating component 4 covers at least a portion of the second weld mark 52 .

[0620] The first insulating component 4 may cover a portion of the second weld mark 52 or may cover the entire second weld mark 52 .

[0621] The first insulating component 4 can block burrs, metal debris and other components on the second weld mark 52, reduce the risk of burrs, metal debris and other components piercing the separator 3 and contacting the second pole piece 2, reduce the risk of short circuit, and improve the reliability of the battery cell 100.

[0622] In some embodiments, along the direction from the active material layer 20 to the first connection portion 31 , the first insulating component 4 protrudes from the edge of the second weld mark 52 away from the active material layer 20 .

[0623] The first insulating component 4 can completely cover the second weld mark 52 to block burrs, metal debris and other components on the entire second weld mark 52, reduce the risk of burrs, metal debris and other components piercing the isolation member 3 and contacting the second pole piece 2, reduce the risk of short circuit, and improve the reliability of the battery cell 100.

[0624] Figure 34 A partial cross-sectional schematic diagram of an electrode assembly of a battery cell provided in some other embodiments of the present application; Figure 35 Schematic diagram of a first pole piece of a battery cell in a flattened state provided in some other embodiments of the present application, wherein the conductive member is omitted; Figure 36 for Figure 35 Enlarged view of the circled part.

[0625] Reference Figures 34 to 36 In some embodiments, the current collector 10 further includes a conductive protection layer 13 , at least a portion of the conductive protection layer 13 is located between the active material layer 20 and the metal layer 12 .

[0626] The conductive protective layer 13 may be a conductive structure disposed between the active material layer 20 and the metal layer 12. The conductive structure is conductive, enabling the battery cell 100 to output or input electrical energy. The conductive protective layer 13 may be a structure of uniform thickness or a structure of unequal thickness.

[0627] 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 1222 and protrudes out of the active material layer 20 .

[0628] Illustratively, the entire conductive protection layer 13 is located between the active material layer 20 and the first metal part 121 .

[0629] 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 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 and the metal layer 12, thereby improving the performance of the battery cell 100.

[0630] 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, which will cause 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 and at the same time protect the metal layer 12, reducing the risk of cracks in the metal layer 12 caused by rolling the active material layer 20, which is beneficial to improving the current carrying capacity of the metal layer 12.

[0631] In some embodiments, along the direction from the active material layer 20 to the first connection portion 31 , the conductive protection layer 13 protrudes from the end surface of the active material layer 20 facing the first connection portion 31 .

[0632] The conductive protective layer 13 protrudes from the active material layer 20. The conductive protective layer 13 can completely separate the metal layer 12 and the active material layer 20. In addition, it can also provide an epitaxial space for the active material layer 20 during the rolling process, which is conducive to the subsequent conductive protective layer 13 being able to completely separate the metal layer 12 and the active material layer 20.

[0633] 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.

[0634] In some embodiments, along the direction from the active material layer 20 to the first connection portion 31 , the conductive protection layer 13 protrudes from the end surface of the active material layer 20 toward the first connection portion 31 by a length S3, where 0.3 mm ≤ S3 ≤ 0.8 mm.

[0635] The value of S3 can be 0.3 mm, 0.8 mm, or any value between 0.3 mm and 0.8 mm. For example, the value of S3 can be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, and 0.8 mm.

[0636] The design of S3≥0.3mm allows the conductive protective layer 13 to completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 13 has better protection for the metal layer 12, and the first pole piece 1 has better current carrying capacity, which is beneficial to improving the fast charging performance and reliability of the battery cell 100. The design of S3≤0.8mm prevents the conductive protective layer 13 from being too large, which is beneficial to saving the internal space of the battery cell 100 and improving the energy density of the battery cell 100.

[0637] By adopting the technical solution of this embodiment, the current capacity and energy density of the battery cell 100 can be better taken into account.

[0638] In some embodiments, the current collector 10 further includes a conductive protective layer 13. At least a portion of the conductive protective layer 13 is located between the active material layer 20 and the metal layer 12. Along the first direction Z, the conductive protective layer 13 and the first weld mark 51 are spaced apart. The first connecting portion 31 is not welded to the conductive protective layer 13, which reduces the risk of cold solder joints and improves the reliability of the welding between the first connecting portion 31 and the metal layer 12.

[0639] In some embodiments, the conductive protection layer 13 and the first connection portion 31 are spaced apart along the first direction Z. Embodiments of the present application can reduce the possibility of overlap between the first connection portion 31 and the conductive protection layer 13, reduce interference of the conductive protection layer 13 with the connection between the first connection portion 31 and the metal layer 12, and improve the connection strength and current carrying capacity between the first connection portion 31 and the metal layer 12.

[0640] In some embodiments, at least one of the first insulating member 4 and the second insulating member 6 covers a portion of the conductive protection layer 13 between the first connecting portion 31 and the active material layer 20 .

[0641] The metal layer 12 includes a first metal portion 121 and a second metal portion 122 arranged and connected along a first direction Z. The first metal portion 121 is covered with the active material layer 20, while the second metal portion 122 is not. The second metal portion 122 includes a transition portion 1222 and at least one protrusion 1221; the transition portion 1222 connects between the first metal portion 121 and the protrusion 1221. Along the second direction X, the transition portion 1222 is larger than the sum of the dimensions of all protrusions 1221. The second direction X is perpendicular to the first direction Z and the thickness direction Y of the current collector. The first connection portion 31 is welded to the second metal portion 122, forming a first weld mark 51.

[0642] In some embodiments, the thickness of at least a portion of the first metal portion 121 is smaller than the thickness of the transition portion 1222 .

[0643] For example, the transition portion 1222 has a uniform thickness or substantially a uniform thickness structure, and the first metal portion 121 also has a uniform thickness or substantially a uniform thickness structure. The thickness t1 of the transition portion 1222 is greater than the thickness of the first metal portion 121 .

[0644] For example, the first metal part 121 may have unequal thickness. The thickness of the first metal part 121 is set to increase along the direction of the first metal part 121 pointing to the protrusion 1221. It can be increased in steps or slowly. The thickness of the part of the first metal part 121 away from the transition part 1222 is less than the thickness of the transition part 1222.

[0645] The thickness t1 of the transition portion 1222 is relatively large, and the transition portion 1222 has good current-carrying capacity, which is beneficial to improving the current-carrying capacity of the first pole piece 1 , reducing the heat generation of the battery cell 100 , and improving the fast charging performance and reliability of the battery cell 100 .

[0646] In some embodiments, the first metal portion 121 includes a first sub-portion 1211 and a second sub-portion 1212, the first sub-portion 1211 is connected between the second sub-portion 1212 and the transition portion 1222, the first sub-portion 1211 and the second sub-portion 1212 are covered with an active material layer 20, the thickness of the first sub-portion 1211 is greater than the thickness of the second sub-portion 1212, and the thickness of the transition portion 1222 is greater than or equal to the thickness of the first sub-portion 1211.

[0647] The first metal part 121 can be a structure of unequal thickness. Along the direction of the first metal part 121 pointing to the protrusion 1221, the first metal part 121 is divided into two parts. The part close to the transition part 1222 is the first sub-part 1211, and the part away from the transition part 1222 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.

[0648] In some examples, the first subsection 1211 may be an equal thickness structure, and the second subsection 1212 may be an equal thickness structure; the thickness t2 of the first subsection 1211 is greater than the thickness t3 of the second subsection 1212, so that the first subsection 1211 and the second subsection 1212 form a step structure.

[0649] The thickness t1 of the transition portion 1222 is greater than or equal to the thickness t2 of the first sub-portion 1211. For example, the thickness t1 of the transition portion 1222 may be equal to the thickness t2 of the first sub-portion 1211, so that the transition portion 1222 and the first sub-portion 1211 form a structure of equal thickness; or the thickness t1 of the transition portion 1222 may be greater than the thickness t3 of the second sub-portion 1212, so that the first sub-portion 1211 and the transition portion 1222 form a stepped structure.

[0650] 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 portion 121 to the protrusion 1221. 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 portion 121 to the protrusion 1221, while the second segment is generally of uniform thickness, with the thickness of the second segment equal to the thickness t1 of the transition portion 1222. The first segment gradually increases from the thickness t3 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 or less than the thickness t1 of the transition portion 1222.

[0651] During the use of the battery cell 100, the electrons generated by the active material layer 20 are gradually gathered on the transition portion 1222 through the first metal portion 121 along the direction of the first metal portion 121 pointing to the protrusion 1221. The number of electrons flowing through the portion of the first metal portion 121 close to the transition portion 1222 is greater than the number of electrons flowing through the portion of the first metal portion 121 away from the transition portion 1222. This requires that the flow capacity of the portion of the first metal portion 121 close to the transition portion 1222 is greater than the flow capacity of the portion of the first metal portion 121 away from the transition portion 1222.

[0652] The first sub-section 1211 of the embodiment of the present application is connected between the second sub-section 1212 and the transition section 1222, and the thickness t2 of the first sub-section 1211 is greater than the thickness t3 of the second sub-section 1212, so that the flow capacity of the first sub-section 1211 close to the transition section 1222 is greater than the flow capacity of the second sub-section 1212 away from the transition section 1222. This can reduce the restriction on the current, improve the 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.

[0653] In some embodiments, 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; the thickness of the first protective portion 131 is less than the thickness of the second protective portion 132.

[0654] In some examples, along the first direction Z, the portion of the conductive protective layer 13 located between the first sub-portion 1211 and the active material layer 20 may be the first protective portion 131, and the portion of the conductive protective layer 13 located between the second sub-portion 1212 and the active material layer 20 may be the second protective portion 132, wherein the thickness t4 of the first protective portion 131 is less than the thickness t5 of the second protective portion 132, and the thickness t2 of the first sub-portion 1211 is greater than the thickness t3 of the second sub-portion 1212, which can reduce the difference in thickness between the current collector 10 at the first protective portion 131 and the second protective portion 132.

[0655] For example, the first protection part 131 is composed of a third section and a fourth section, the third section is located between the above-mentioned first section and the active material layer 20, the fourth section is located between the above-mentioned second section and the active material layer 20, and the third section is located between the fourth section and the second protection part 132. Along the direction from the first metal part 121 to the protrusion 1221, the thickness of the third section gradually decreases, and the fourth section is generally a uniform thickness structure, so that the thickness t4 of the first protection part 131 can be adapted to the thickness t2 of the first sub-section 1211, so that the surface of the conductive protection layer 13 facing away from the insulating substrate 11 is close to a plane.

[0656] 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.

[0657] In some embodiments, the conductive protection layer 13 further includes a third protection portion 133 , which covers the surface of the transition portion 1222 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 .

[0658] In some examples, along the first direction Z, 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 located in the middle is a first protection portion 131. The thickness t4 of the first protection portion 131 is less than the thickness t5 of the second protection portion 132, while the thickness t2 of the first sub-portion 1211 is greater than the thickness t3 of the second sub-portion 1212. This can reduce the difference in thickness between the first protection portion 131 and the second protection portion 132 of the current collector 10. Similarly, the thickness t6 of the third protection portion 133 is less than or equal to the thickness t4 of the first protection portion 131, and the thickness t1 of the transition portion 1222 is greater than or equal to the thickness t2 of the first sub-portion 1211. This can reduce the difference in thickness between the first protection portion 131 and the third protection portion 133 of the current collector 10, thereby facilitating the surface of the conductive protection layer 13 facing away from the metal layer 12 to be closer to a plane.

[0659] For example, the second protective portion 132, the third protective portion 133, the transition portion 1222 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 t2 of the first sub-portion 1211 and the thickness t4 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.

[0660] The provision of the third protection portion 133 allows the conductive protection layer 13 to protrude from the active material layer 20 , thereby better separating the active material layer 20 and the metal layer 12 . In addition, the thickness of the third protection portion 133 is not too large, which is beneficial to reducing material waste and saving the production cost of the battery cell 100 .

[0661] In some embodiments, the thickness t7 of the protruding portion 1221 is greater than or equal to the thickness t1 of the transition portion 1222 .

[0662] For example, the thickness t7 of the protruding portion 1221 may be equal to the thickness t1 of the transition portion 1222 , so that the protruding portion 1221 and the transition portion 1222 form a structure of equal thickness.

[0663] For example, the thickness t7 of the protruding portion 1221 may also be greater than the thickness t1 of the transition portion 1222 , so that the protruding portion 1221 and the transition portion 1222 form a step structure.

[0664] The thickness t7 of the protrusion 1221 is relatively thick, which can improve the flow capacity of the protrusion 1221, which is beneficial to 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 and reliability of the battery cell 100.

[0665] In some embodiments, the thickness of the second active material portion 22 is t8, where 0.002≤(t1-t3) / t8≤0.08.

[0666] t1-t3 may refer to the difference between the thickness of the transition portion 1222 and the second sub-portion 1212 , so as to represent the degree of thickening of the transition portion 1222 .

[0667] The value of (t1-t3) / t8 can be 0.002, 0.08, and any value between 0.002-0.08; for example,

[0668] The value of (t1-t3) / t8 can be, but is not limited to, 0.002, 0.003, 0.004, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, and 0.08.

[0669] The setting of 0.002≤(t1-t3) / t8≤0.08 allows the thickness difference between the transition portion 1222 and the second sub-portion 1212 to be within the thickness error range of the active material layer 20. In this way, the thickening of the transition portion 1222 is not likely to cause surface bulging of the active material layer 20, which can reduce subsequent rolling damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, and is beneficial to improving the reliability of the battery cell 100.

[0670] In some embodiments, 0.003≤(t1-t3) / t8≤0.06. In this embodiment of the present application, the thickness difference between the transition portion 1222 and the second sub-portion 1212 can be better positioned within the thickness difference range of the active material layer 20. This makes it less likely that a thicker transition portion 1222 will cause surface protrusions in the active material layer 20, thereby reducing subsequent rolling damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, thereby improving the reliability of the battery cell 100.

[0671] In some embodiments, 60 μm ≤ t8 ≤ 250 μm.

[0672] It can be understood that the value of t8 can be 60μm, 250μm, and any value between 60μm-250μm; for example, the value of t8 can be but is not limited to 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, and 250μm.

[0673] The design of t8≥60μm can enable the battery cell 100 to have a higher capacity; the design of t8≤250μm ensures that the distance for electrons in the portion of the active material layer 20 close to the metal layer 12 to escape is not too long, and the electrons in the portion of the active material layer 20 close to the metal layer 12 can escape easily, which is beneficial to improving the capacity of the battery cell 100.

[0674] The thickness of the second active material portion 22 is within an appropriate range, and the volume of the active material layer 20 is reasonably set, which is conducive to improving the fast charging performance and usage reliability of the battery cell 100. It can also reduce the risk of ion escape difficulty in the area of the active material layer 20 close to the conductive layer, thereby improving the performance of the battery cell 100.

[0675] In some embodiments, 80 μm ≤ t8 ≤ 180 μm.

[0676] By adopting the technical solution of this embodiment, the setting of 80μm≤t8≤180μm, the thickness of the second active material part 22 is within a more appropriate range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and use reliability of the battery cell 100, and can also reduce the risk of difficulty in ion escape in the area of the active material layer 20 close to the conductive layer, thereby improving the performance of the battery cell 100.

[0677] In some embodiments, 0.2 μm ≤ t1 − t3 ≤ 4.5 μm.

[0678] It can be understood that the value of t1-t3 can be 0.2μm, 4.5μm and any value between 0.2μm and 4.5μm; for example, the value of t1-t3 can be but not limited to 0.2μm, 0.3μm, 0.1μm, 0.5μm, 1μm, 1.5μm, 1.75μm, 2μm, 3μm, 4μm, and 4.5μm.

[0679] By adopting the technical solution of this embodiment, the design of 0.2μm≤t1-t3≤4.5μm, the transition portion 1222 is reasonably thickened. On the basis of improving the current flow capacity, the thickness of the transition portion 1222 is not too large to occupy a large space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0680] In some embodiments, 0.3 μm ≤ t1 − t3 ≤ 1.75 μm.

[0681] By adopting the technical solution of this embodiment and the design of 0.3 μm≤t1-t3≤1.75 μm, the thickness of the transition portion 1222 is more reasonably increased, the current carrying capacity is better, and it is more conducive to improving the energy density of the battery cell 100.

[0682] In some embodiments, 1<t1 / t3≤4, optionally, 1.5<t1 / t3≤2.5.

[0683] t1 / t3 may refer to the ratio of the thickness t1 of the transition portion 1222 to the thickness t3 of the second sub-portion 1212 , and may also represent the degree of thickening of the transition portion 1222 .

[0684] It is understandable that the value of t1 / t3 can be 4 or any value between 1 and 4; for example, the value of t1 / t3 can be, but is not limited to, 1.1, 1.5, 2, 2.5, 3, 3.5, or 4.

[0685] By adopting the technical solution of this embodiment, the design of 1<t1 / t3≤4, the transition portion 1222 is reasonably thickened. On the basis of improving the current flow capacity, the thickness of the transition portion 1222 is not too large to occupy a large space and weight, which is beneficial to improving the energy density of the battery cell 100.

[0686] In some embodiments, 1.5≤t1 / t3≤2.5. By adopting the technical solution of this embodiment, the thickness of the transition portion 1222 is more reasonable, the current capacity is better, and it is more conducive to improving the energy density of the battery cell 100.

[0687] In some embodiments, 1 μm ≤ t1 ≤ 5 μm.

[0688] It can be understood that the value of t1 can be 1μm, 5μm and any value between 1μm and 5μm; for example, the value of t1 can be but is not limited to 1μm, 1.1μm, 1.2μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, and 5μm.

[0689] By adopting the technical solution of this embodiment, the design of 1μm≤t1≤5μm, the thickness of the transition portion 1222 is reasonably designed, which is conducive to improving the flow capacity. In addition, the thickness of the transition portion 1222 is not too large to occupy a large space and weight, which is conducive to improving the energy density of the battery cell 100.

[0690] In some embodiments, 1.2 μm ≤ t1 ≤ 3.5 μm.

[0691] By adopting the technical solution of this embodiment, the design of 1.2 μm≤t1≤3.5 μm, the thickness design of the transition portion 1222 is more reasonable, the current flow capacity is better, and it is more conducive to improving the energy density of the battery cell 100.

[0692] In some embodiments, 0.03≤t6 / t5≤0.95.

[0693] t6 / t5 may refer to the ratio of the thickness of the third protecting portion 133 to the thickness of the second protecting portion 132 , which may represent the degree of thinning of the third protecting portion 133 relative to the second protecting portion 132 .

[0694] It can be understood that the value of t6 / t5 can be 0.03, 0.95, and any value between 0.03 and 0.95; for example, the value of t6 / t5 can be but is not limited to 0.03, 0.1, 0.125, 0.15, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.95.

[0695] By adopting the technical solution of this embodiment, the design of 0.03≤t6 / t5≤0.95, the thinning degree of the conductive protective layer 13 is reasonable, which can be better adapted to the thickening degree of the transition portion 1222, which is beneficial for the surface of the conductive protective layer 13 facing away from the metal layer 12 to be close to a plane, which is beneficial for reducing rolling damage and improving the current carrying capacity of the metal layer 12.

[0696] In some embodiments, 0.125≤t6 / t5≤0.8.

[0697] By adopting the technical solution of this embodiment, the design of 0.125≤t6 / t5≤0.8, the thinning degree of the conductive protective layer 13 is more reasonable, which can be better adapted to the thickening degree of the transition portion 1222, which is beneficial for the surface of the conductive protective layer 13 facing away from the metal layer 12 to be close to a plane, which is beneficial for reducing rolling damage and improving the current carrying capacity of the metal layer 12.

[0698] In some embodiments, 0.5 μm ≤ t6 ≤ 4 μm.

[0699] It is understandable that the value of t6 can be 0.5μm, 4μm, and any value between 0.5μm and 4μm; for example, the value of t6 can be but is not limited to 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 4μm, and 5μm.

[0700] By adopting the technical solution of this embodiment, the setting of 0.5μm≤t6≤4μm makes the third protection portion 133 have a certain thickness, thereby reducing the risk of cracking of the metal layer 12; in addition, the third protection portion 133 will not protrude from the second protection portion 132 due to the third protection portion 133 being too thick, and material accumulation can be reduced, thereby reducing production costs.

[0701] In some embodiments, 1 μm≤t6≤2 μm.

[0702] By adopting the technical solution of this embodiment and setting 1 μm≤t6≤2 μm, the third protection portion 133 has a more reasonable thickness, thereby better reducing the risk of cracking of the metal layer 12 and the production cost.

[0703] In some embodiments, along the first direction Z, the size of the first sub-portion 1211 is W1, and the size of the second sub-portion 1212 is W2, wherein W1 / (W1+W2)≤0.45.

[0704] For example, the size W1 of the first sub-portion 1211 may refer to the width of the first sub-portion 1211 , and the size W2 of the second sub-portion 1212 may refer to the width of the second sub-portion 1212 . W1+W2 may refer to the width of the first metal portion 121 .

[0705] W1 / (W1+W2) may refer to the ratio of the first sub-portion 1211 to the first metal portion 121 in the width direction of the first pole piece 1 .

[0706] It is understandable that the value of W1 / (W1+W2) can be 0.45 and any value between 0-0.45; for example, the value of W1 / (W1+W2) can be but is not limited to 0.001, 0.1, 0.2, 0.3, 0.4, 0.45.

[0707] By adopting the technical solution of this embodiment, the design of W1 / (W1+W2)≤0.45 allows the active material layer 20 to cover the first sub-section 1211, thereby improving the current flow capacity and reducing the heat generation of the battery cell 100; in addition, along the first direction Z, the first sub-section 1211 does not occupy a large area, which is beneficial to reducing the occupied space and weight of the first sub-section 1211, and is beneficial to improving the energy density of the battery cell 100.

[0708] In some embodiments, along the first direction Z, the size of the first sub-portion 1211 is W2, where 10 mm ≤ W2 ≤ 100 mm.

[0709] It can be understood that the value of W2 can be 10mm, 100mm and any value between 10mm-100mm; for example, the value of W2 can be but is not limited to 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm.

[0710] By adopting the technical solution of this embodiment, the design of 10mm≤W2≤100mm allows the active material layer 20 to cover the first sub-section 1211, thereby improving the current flow capacity and reducing the heat generation of the battery cell 100; in addition, along the first direction Z, the first sub-section 1211 does not occupy a large area, which is beneficial to reducing the occupied space and weight of the first sub-section 1211, and is beneficial to improving the energy density of the battery cell 100.

[0711] Figure 37 Schematic diagram of a first insulating component of a battery cell provided in some embodiments of the present application.

[0712] Reference Figure 37 In some embodiments, the first insulating component 4 includes an insulating base layer 4 a and an adhesive layer 4 b , and at least a portion of the adhesive layer 4 b is bonded between the insulating base layer 4 a and the first connecting portion 31 .

[0713] For example, the insulating base layer 4a may refer to the insulating main body of the first insulating component 4, and the adhesive layer 4b may refer to the adhesive covering the surface of the insulating base layer 4a. For example, the first insulating component 4 is in the form of an adhesive tape.

[0714] For example, the insulating base layer 4a may be made of at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and block copolymers thereof, and the adhesive layer 4b may be made of at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0715] The insulating base layer 4a can have high structural strength, which can block burrs and resist puncture by burrs, thereby improving the insulation effect. Compared with the adhesive layer 4b, the insulating base layer 4a has higher strength, and the insulating base layer 4a is less deformed during the bonding process of the first insulating component 4. The adhesive layer 4b can stably fix the insulating base layer 4a to the first pole piece 1, reducing the risk of the first insulating component falling off.

[0716] In some embodiments, the first insulating member 4 is a tape. The tape is easy to fully cover, which helps to reduce the risk of leaky coverage and the risk of internal short circuits in the battery cell 100.

[0717] In some embodiments, the thickness of the insulating base layer 4 a ranges from 6 μm to 15 μm.

[0718] The insulating base layer 4a has a thickness T1, 6 μm ≤ T1 ≤ 15 μm. The value of T1 can be 6 μm, 15 μm, or any value between 6 μm and 15 μm. For example, the value of T1 can be, but is not limited to, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or 16 μm.

[0719] The design of T1≥6μm ensures that the insulating base layer 4a has a certain thickness, and the insulating base layer 4a can block burrs and achieve insulation; the design of T1≤15μm ensures that the thickness of the insulating base layer 4a is not too large, which is beneficial to reducing the volume occupied by the first insulating component 4 and improving the energy density of the battery cell 100.

[0720] By adopting the technical solution of this embodiment, it is possible to take both the internal insulation and energy density of the battery cell 100 into consideration to a certain extent.

[0721] In some embodiments, the thickness of the adhesive layer 4b ranges from 0.5 μm to 3 μm.

[0722] The thickness of the adhesive layer 4b is T2, 0.5μm≤T2≤3μm. It can be understood that the value of T2 can be 0.3μm, 3μm and any value between 0.3μm-3μm. For example, the value of T2 can be but not limited to 0.3μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm.

[0723] The design of T2 ≥ 0.5 μm ensures that the adhesive layer 4 b has a certain thickness, so that the first insulating component 4 can be stably bonded to the first pole piece 1, thereby improving the insulation reliability of the first insulating component 4; the design of T2 ≤ 3 μm ensures that the thickness of the adhesive layer 4 b is not too large, which is beneficial to reducing the volume occupied by the first insulating component 4 and improving the energy density of the battery cell 100.

[0724] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell 100 can be taken into consideration.

[0725] In some embodiments, the thickness of the insulating base layer 4a ranges from 6 μm to 15 μm; the thickness of the adhesive layer 4b ranges from 0.5 μm to 3 μm.

[0726] By adopting the technical solution of this embodiment, both the insulation reliability and the energy density of the battery cell 100 can be taken into consideration.

[0727] Figure 38 Schematic partial cross-sectional views of electrode assemblies of battery cells provided in some other embodiments of the present application.

[0728] Reference Figure 38 In some embodiments, the portion of the first insulating member 4 covering the active material layer 20 is configured to allow ions to pass therethrough.

[0729] The present application can reduce the barrier of the first insulating component 4 to ions and reduce the capacity loss of the first pole piece 1 .

[0730] In some embodiments, a portion of the first insulating member 4 covering the active material layer 20 is provided with a through hole 4c. The through hole 4c can serve as a channel for ions to pass through.

[0731] The number of through holes 4c may be one or more.

[0732] In some embodiments, the insulating base layer 4 a covers the active material layer 20 , and no adhesive layer 4 b is present between the insulating base layer 4 a and the active material layer 20 .

[0733] In some embodiments, the insulating base layer 4a has a microporous structure. For example, the porosity of the insulating base layer 4a is 20%-80%.

[0734] Reference Figures 2 to 17 The embodiment of the present application provides a battery cell 100, which includes an end cap 201, a housing 202, and an electrode assembly 101. The electrode assembly 101 is mounted on the housing 202, and the end cap 201 covers the opening of the housing 202 to seal the housing 202. The end cap 201 is provided with an electrode lead-out portion 2011.

[0735] The electrode assembly 101 includes a first electrode sheet 1, a second electrode sheet 2, and a separator 3 that are wound together. The separator 3 is located between the first electrode sheet 1 and the second electrode sheet 2. The first electrode sheet 1 and the second electrode sheet 2 have opposite polarities. The first electrode sheet 1 can be a positive electrode sheet, and the second electrode sheet 2 can be a negative electrode sheet.

[0736] The first electrode sheet 1 includes a current collector 10, two active material layers 20, and two conductive members 30. The current collector 10 includes an insulating substrate 11 and two metal layers 12. The two metal layers 12 are disposed on opposite sides of the insulating substrate 11 along the thickness direction Y of the current collector. The two active material layers 20 are disposed on the two metal layers 12, respectively.

[0737] The metal layer 12 includes a first metal portion 121 and a second metal portion 122 arranged and connected along a first direction Z. The first metal portion 121 is covered with an active material layer 20, while the second metal portion 122 is not covered with the active material layer 20. The second metal portion 122 includes a transition portion 1222 and a plurality of protrusions 1221. The transition portion connects between the first metal portion 121 and the plurality of protrusions 1221. The plurality of protrusions 1221 are spaced apart along a second direction X. The second direction X, the first direction Z, and the thickness direction Y of the current collector are mutually perpendicular. For example, the second direction X may be the winding direction of the first pole piece 1.

[0738] The conductive member 30 includes a first connecting portion 31 and multiple second connecting portions 32. The first connecting portion 31 includes multiple first connecting sub-portions 311 and second connecting sub-portions 312. The second connecting sub-portions 312 are located on the side of the transition portion 1222 facing away from the insulating substrate 11 and are welded to the transition portion 1222. The multiple first connecting sub-portions 311 are arranged in a one-to-one correspondence with the multiple protrusions 1221. The first connecting sub-portions 311 cover the corresponding protrusions 1221 and are welded to the protrusions 1221. The second connecting sub-portions 312 extend continuously along the second direction X and are connected to the multiple first connecting sub-portions 311.

[0739] The second connecting portions 32 correspond to the first connecting sub-portions 311 one by one, and extend from one end of the corresponding first connecting sub-portion 311 away from the second connecting sub-portion 312. The second connecting portion 32 protrudes from the protrusion 1221 along the direction from the active material layer 20 to the first connecting portion 31.

[0740] The second connection portions 32 of the plurality of conductive members 30 are connected to the electrode lead-out portion 2011 in a layered manner.

[0741] The electrode assembly 101 further includes two first insulating components 4, which are located on both sides of the first electrode piece 1. The two first insulating components 4 are attached to the two conductive members 30 respectively.

[0742] Along the direction from the active material layer 20 to the first connecting portion 31, the first insulating component 4 protrudes from the end surface of the second connecting sub-portion 312 facing away from the active material layer 20; along the direction from the first connecting portion 31 to the active material layer 20, the first insulating component 4 protrudes from the end surface of the second connecting sub-portion 312 facing the active material layer 20.

[0743] Optionally, the first insulating component 4 completely covers the plurality of first connecting sub-portions 311 and the second connecting sub-portions 312. Optionally, the first insulating component 4 completely covers the transition portion 1222.

[0744] According to some embodiments of the present application, the present application further provides a battery device 1100 , comprising a plurality of battery cells 100 according to any of the above embodiments.

[0745] The present application also provides an electrical device, comprising the battery device 1100 of any of the above embodiments, the battery device 1100 being configured to provide electrical energy to the electrical device. The electrical device may be any of the aforementioned devices or systems employing the battery device 1100.

[0746] 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 of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: The housing is provided with an electrode lead portion; an electrode assembly, at least partially housed in the housing, the electrode assembly comprising a first electrode piece and a first insulating component; The first electrode sheet includes a conductive member, a current collector, and an active material layer. The current collector includes an insulating substrate and a metal layer. The insulating substrate, the metal layer, and the active material layer are stacked along the thickness direction of the current collector. At least a portion of the metal layer is located between the insulating substrate and the active material layer. The conductive member is used to electrically connect the metal layer and the electrode lead portion. The conductive member includes a first connecting portion, the first connecting portion is located on a side of the metal layer away from the insulating substrate and connected to the metal layer, the active material layer and the first connecting portion are arranged along a first direction, and the first direction is perpendicular to the thickness direction of the current collector; At least part of the first insulating component is located on a side of the first connecting portion away from the metal layer and is attached to the first connecting portion; along the direction of the first connecting portion pointing to the active material layer, the first insulating component protrudes from the first end surface of the first connecting portion facing the active material layer.

2. The battery cell according to claim 1, wherein: Along the first direction, the first connection portion and the active material layer are spaced apart.

3. The battery cell according to claim 2, characterized in that: The first insulating member at least partially covers a region of the metal layer between the first connecting portion and the active material layer.

4. The battery cell according to claim 2, characterized in that: Along the first direction, a portion of the first insulating member is located between the first connecting portion and the active material layer; A portion of the first insulating member located between the first connecting portion and the active material layer is attached to the metal layer.

5. The battery cell according to claim 2, characterized in that: The electrode assembly includes a second insulating component, which is arranged on a surface of the metal layer facing away from the insulating substrate; In the first direction, at least a portion of the second insulating member is located between the first connecting portion and the active material layer.

6. The battery cell according to claim 5, characterized in that A portion of the first insulating component is located on a side of the second insulating component facing away from the metal layer and is connected to the second insulating component.

7. The battery cell according to claim 1, characterized in that The first insulating member is further connected to the active material layer.

8. The battery cell according to claim 1, wherein: The first insulating member covers a portion of the active material layer.

9. The battery cell according to claim 8, characterized in that The portion of the first insulating member covering the active material layer is configured to allow ions to pass therethrough.

10. The battery cell according to claim 8, characterized in that A portion of the first insulating member covering the active material layer is provided with a through hole.

11. The battery cell according to claim 8, characterized in that The first insulating member is configured to block passage of ions.

12. The battery cell according to claim 8, characterized in that The active material layer includes a first active material portion and a second active material portion arranged along the first direction, the first active material portion is located on a side of the second active material portion facing the first connecting portion, a thickness of the first active material portion at an end away from the second active material portion is less than a thickness of the second active material portion, and the thickness of the first active material portion decreases along the direction of the active material layer toward the first connecting portion; The first insulating member covers at least a portion of the first active material portion.

13. The battery cell according to claim 8, characterized in that Along the first direction, a size of a portion of the first insulating component covering the active material layer is 0.2 mm to 1 mm.

14. The battery cell according to any one of claims 1 to 13, characterized in that: The metal layer includes a first metal portion and a second metal portion arranged and connected along the first direction, the first metal portion is covered with the active material layer, and the second metal portion is not covered with the active material layer; The first connecting portion is welded to the second metal portion to form a first weld mark.

15. The battery cell according to claim 14, characterized in that The second metal portion includes at least one protrusion, and along a second direction, the sum of the dimensions of all the protrusions is smaller than the dimension of the first metal portion, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; The first connecting portion includes at least one first connecting sub-portion, the first connecting sub-portion is located on a side of the protruding portion away from the insulating base, and the first connecting sub-portion corresponds to the protruding portion one-to-one.

16. The battery cell according to claim 15, characterized in that The first insulating component includes at least one first insulator portion, the first insulator portion covers a surface of the first connecting portion facing away from the protruding portion, and the first insulator portion corresponds to the first connecting portion in a one-to-one manner.

17. The battery cell according to claim 16, characterized in that The first insulating component further includes a second insulating portion connected to the first insulating portion. Along the first direction, the second insulating portion is located on a side of the first insulating portion facing the active material layer.

18. The battery cell according to claim 16, characterized in that The first insulating component further includes a third insulator portion connected to the first insulator portion, and the third insulator portion and the first insulator portion are arranged along the second direction.

19. The battery cell according to claim 18, characterized in that The current collector includes two metal layers, and the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector; The first electrode sheet includes two active material layers and two conductive members, the two active material layers are respectively provided on the two metal layers, and the first connecting portions of the two conductive members are respectively connected to the second metal portions of the two metal layers; The electrode assembly includes two first insulating members, and the two first insulating members are respectively attached to the two first connecting portions.

20. The battery cell according to claim 19, characterized in that The third insulator portions of the two first insulating components are bonded and / or connected.

21. The battery cell according to claim 16, characterized in that The first insulating component further includes a fourth insulating portion connected to the first insulating portion. Along the first direction, the fourth insulating portion is located on a side of the first insulating portion facing away from the active material layer.

22. The battery cell according to claim 16, characterized in that The first connecting sub-portion is welded to the protruding portion to form a first weld print portion, and the first weld print includes the first weld print portion; the first insulating sub-portion covers at least a portion of the first weld print portion.

23. The battery cell according to claim 22, characterized in that Along the first direction, both ends of the first weld portion do not exceed the first insulator portion.

24. The battery cell according to claim 15, characterized in that There are multiple protrusions, and the multiple protrusions are spaced apart along the second direction; The first connecting portion includes a plurality of first connecting sub-portions, the plurality of first connecting sub-portions are spaced apart along the second direction, and the plurality of first connecting sub-portions correspond one-to-one to the plurality of protruding portions.

25. The battery cell according to claim 24, characterized in that The first insulating component includes a plurality of first insulator portions arranged along the second direction. The first insulator portions cover a surface of the first connecting portion facing away from the protruding portion. The first insulator portions are arranged in a one-to-one correspondence with the first connecting portion.

26. The battery cell according to claim 25, characterized in that The first insulating component further includes a second insulating portion, and in the first direction, the second insulating portion is located on a side of the plurality of first insulating portions facing the active material layer; The second insulator portion continuously extends along the second direction and is connected to the plurality of first insulator portions.

27. The battery cell according to claim 25, characterized in that The first insulating component further includes a plurality of second insulator portions, wherein the plurality of first insulator portions and the plurality of second insulator portions are arranged in a one-to-one correspondence, and the first insulator portions are connected to the corresponding second insulator portions; In the first direction, the second insulator portion is located on a side of the first insulator portion facing the active material layer.

28. The battery cell according to claim 25, characterized in that The first insulating component includes a plurality of third insulator portions arranged along the second direction, and both ends of each first insulating portion along the second direction are respectively connected to two of the third insulator portions.

29. The battery cell according to claim 28, characterized in that A plurality of the first insulator portions and a plurality of the third insulator portions are alternately arranged along the second direction, and two adjacent first insulator portions are connected by one third insulator portion.

30. The battery cell according to claim 28, characterized in that Along the second direction, two adjacent first insulator parts are provided with two spaced-apart third insulator parts.

31. The battery cell according to claim 25, characterized in that The first insulating component further includes a plurality of fourth insulator portions, wherein the plurality of first insulator portions and the plurality of fourth insulator portions are arranged in a one-to-one correspondence, and the first insulator portions are connected to the corresponding fourth insulator portions; In the first direction, the fourth insulator portion is located on a side of the first insulator portion facing away from the active material layer.

32. The battery cell according to claim 24, characterized in that Each of the first connecting sub-parts has a second end surface at one end facing the active material layer; the second end surfaces of the plurality of first connecting sub-parts form the first end surface.

33. The battery cell according to claim 15, characterized in that The second metal portion further includes a transition portion connected between the first metal portion and the protruding portion; Along the second direction, a dimension of the transition portion is larger than a sum of dimensions of all the protruding portions.

34. The battery cell according to claim 33, characterized in that The first connecting portion includes a second connecting sub-portion, the second connecting sub-portion is located on a side of the transition portion facing away from the insulating substrate along the thickness direction of the current collector, and the first connecting sub-portion is connected to an end surface of the second connecting sub-portion away from the active material layer; Along the first direction, an end surface of the second connecting sub-part facing the active material layer is the first end surface.

35. The battery cell according to claim 34, characterized in that The first insulating component includes a second insulator portion, the second insulator portion covers the second connecting sub-portion, and the second insulator portion protrudes from the first end surface along a direction from the second metal portion to the first metal portion.

36. The battery cell according to claim 35, characterized in that In the second direction, the second insulating portion protrudes from the second connecting portion.

37. The battery cell according to claim 35, characterized in that The first insulating component further includes a first insulator portion and a third insulator portion, wherein the first insulator portion and the third insulator portion are connected to the second insulator portion; in the first direction, the first insulator portion and the third insulator portion are both located on a side of the second insulator portion facing away from the active material layer; The first insulator portion covers the surface of the first connector portion facing away from the protruding portion; The first insulator portion and the third insulator portion are arranged and connected along the second direction.

38. The battery cell according to claim 35, characterized in that The second connecting sub-portion is welded to the surface of the transition portion facing away from the insulating base to form a second weld print portion, and the first weld print portion includes the second weld print portion; The second insulator portion covers at least a portion of the second weld print portion.

39. The battery cell according to claim 38, characterized in that Along the first direction, both ends of the second welded portion do not exceed the second insulator portion.

40. The battery cell according to claim 38, wherein 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.

41. The battery cell according to claim 34, characterized in that An end surface of the second connector portion away from the active material layer is flush with an end surface of the transition portion away from the first metal portion.

42. The battery cell according to claim 34, characterized in that There are multiple protrusions, and the multiple protrusions are spaced apart along the second direction; The first connecting portion includes the second connecting sub-portion and a plurality of the first connecting sub-portions, the plurality of the first connecting sub-portions are spaced apart along the second direction, and each of the first connecting sub-portions is welded to each of the protruding portions one by one to form a first welded portion; The second connecting sub-portions are continuously arranged along the second direction, welded to the transition portion and form a second welded portion; The first weld print includes the second weld print portion and a plurality of the first weld print portions.

43. The battery cell according to claim 15, 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 connecting sub-portion includes a first connecting protrusion and a second connecting protrusion, the first connecting protrusion is located on a side of the first protruding sub-portion facing away from the insulating base, and the second connecting protrusion is located on a side of the second protruding sub-portion facing away from the insulating base; along the second direction, the size of the first connecting protrusion is larger than the size of the second connecting protrusion; The first insulating component includes at least one first insulating sub-part, and the first insulating sub-part corresponds to the first connecting sub-part one by one; The first insulator portion covers the first connecting protrusion and the second connecting protrusion.

44. The battery cell according to claim 14, characterized in that The second metal portion includes a transition portion, wherein two ends of the transition portion are flush with two ends of the first metal portion in a second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; The first connecting portion includes a second connecting sub-portion, the second connecting sub-portion is located on a side of the transition portion facing away from the insulating base, the second connecting sub-portion is welded to a surface of the transition portion facing away from the insulating base to form a second weld print portion, and the first weld print portion includes the second weld print portion; An end surface of the second connector portion facing the active material layer is the first end surface.

45. The battery cell according to claim 44, characterized in that Along the direction from the first metal portion to the second metal portion, the first insulating component protrudes from the end surface of the second connecting sub-portion facing away from the active material layer.

46. The battery cell according to claim 44, characterized in that In the second direction, both ends of the first insulating component protrude from the second connecting sub-portion respectively.

47. The battery cell according to claim 44, characterized in that The electrode assembly further includes a second pole piece having a polarity opposite to that of the first pole piece, the second pole piece including a main functional portion and a pole ear portion, the pole ear portion extending from an end surface of the main functional portion along the first direction; Along the direction from the active material layer to the first connecting portion, the end surface of the second connecting sub-portion facing away from the active material layer extends beyond the main functional portion.

48. The battery cell according to claim 1, characterized in that The electrode assembly further includes a second pole piece having a polarity opposite to that of the first pole piece, the second pole piece including a main functional portion and a pole ear portion, the pole ear portion extending from an end surface of the main functional portion along the first direction; Along the direction from the active material layer to the first connecting portion, the end surface of the main functional portion facing the electrode ear portion extends beyond the first end surface; The first insulating member separates the first end surface from the main functional portion.

49. The battery cell according to claim 48, characterized in that Along the direction from the active material layer to the first connection portion, the first insulating component extends beyond the main functional portion toward the end surface of the electrode lug portion.

50. The battery cell according to claim 1, characterized in that The current collector includes two metal layers, and the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector; The first electrode sheet includes two active material layers and two conductive components, the two active material layers are respectively provided on the two metal layers, and the first connecting portions of the two conductive components are respectively connected to the two metal layers; The electrode assembly includes two first insulating parts, and the two first insulating parts are respectively attached to the first connecting portions of the two conductive members.

51. The battery cell according to claim 50, characterized in that Parts of the two first insulating components are attached to and / or connected.

52. The battery cell according to claim 50, characterized in that The conductive member further includes a second connecting portion connected to the first connecting portion, wherein in the first direction, the second connecting portion is located on a side of the first connecting portion facing away from the active material layer; the second connecting portion is electrically connected to the electrode lead portion; The second connection portions of the two conductive members are welded to form a second weld mark.

53. The battery cell according to claim 52, characterized in that The first insulating component covers at least a portion of the second weld mark.

54. The battery cell according to claim 53, characterized in that Along the direction from the active material layer to the first connecting portion, the first insulating component protrudes from the edge of the second weld mark away from the active material layer.

55. The battery cell according to claim 1, characterized in that The metal layer includes a first metal portion and a second metal portion arranged and connected along the first direction, the first metal portion is covered with the active material layer, and the second metal portion is not covered with the active material layer; The second metal portion includes a transition portion and at least one protruding portion; the transition portion is connected between the first metal portion and the protruding portion; Along a second direction, a size of the transition portion is greater than the sum of sizes of all the protrusions, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; The first connecting portion is welded to the second metal portion to form a first weld mark.

56. The battery cell according to claim 55, 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.

57. The battery cell according to claim 55, characterized in that The thickness of at least a portion of the first metal portion is smaller than the thickness of the transition portion.

58. The battery cell according to claim 57, 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 transition 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 transition part is greater than or equal to the thickness of the first sub-part.

59. The battery cell according to claim 58, characterized in that The current collector also includes a conductive protective layer, which 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; the thickness of the first protective portion is less than the thickness of the second protective portion.

60. The battery cell according to claim 59, characterized in that The conductive protection layer further includes a third protection portion, which covers a surface of the transition portion facing away from the insulating substrate, and a thickness of the third protection portion is less than or equal to a thickness of the first protection portion.

61. The battery cell according to claim 55, characterized in that The thickness of the protruding portion is greater than or equal to the thickness of the transition portion.

62. The battery cell according to claim 1, characterized in that The conductive component further includes at least one second connection portion connected to the first connection portion. In the first direction, the second connection portion is located on a side of the first connection portion facing away from the active material layer. The second connection portion is electrically connected to the electrode lead portion.

63. The battery cell according to claim 62, characterized in that The first connecting portion includes a plurality of first connecting sub-portions, and the plurality of first connecting sub-portions are spaced apart along a second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector; Each of the first connecting sub-portions is connected to the metal layer; There are multiple second connecting parts, and each of the first connecting sub-parts is connected to each of the second connecting parts in a one-to-one correspondence.

64. The battery cell according to claim 1, characterized in that The first connecting portion is welded to the surface of the metal layer facing away from the insulating substrate to form a first weld mark; Along the first direction, the distance between the first weld mark and the active material layer is S1, characterized in that 0.3 mm ≤ S1 ≤ 5 mm.

65. The battery cell according to claim 1, characterized in that The current collector further includes a conductive protective layer, at least a portion of which is located between the active material layer and the metal layer.

66. The battery cell according to claim 65, characterized in that Along the direction from the active material layer to the first connection portion, the conductive protection layer protrudes from the end surface of the active material layer facing the first connection portion.

67. The battery cell according to claim 66, characterized in that Along the direction from the active material layer to the first connection portion, the conductive protection layer protrudes from the end surface of the active material layer toward the first connection portion by a length ranging from 0.3 mm to 0.8 mm.

68. The battery cell according to claim 65, characterized in that Along the first direction, the conductive protection layer and the first connecting portion are spaced apart.

69. The battery cell according to claim 1, characterized in that The first insulating component includes an insulating base layer and an adhesive layer, and at least a portion of the adhesive layer is adhered between the insulating base layer and the first connecting portion.

70. The battery cell according to claim 69, characterized in that The thickness of the insulating base layer is in the range of 6 μm to 15 μm; and / or the thickness of the adhesive layer is in the range of 0.5 μm to 3 μm.

71. The battery cell according to claim 1, characterized in that Along the first direction, a size of the first insulating component is W, 3 mm ≤ W ≤ 9 mm.

72. A battery device, characterized in that A battery cell comprising the battery cell according to any one of claims 1 to 71.

73. An electrical device, characterized in that: Comprising the battery device of claim 72, the battery device is used to provide electrical energy.

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