Battery monomer, battery device and electric device

Abstract

The utility model belongs to the technical field of battery fast charging, and particularly relates to a single battery, a battery device and a power utilization device.The single battery comprises a shell and an electrode assembly, and the shell is provided with an electrode leading-out part; at least part of the electrode assembly is arranged in the shell; the electrode assembly comprises a first pole piece, the first pole piece comprises a current collector and an active substance layer, the current collector comprises an insulating substrate and a metal layer, the insulating substrate, the metal layer and the active substance layer are stacked in the thickness direction of the current collector, and at least part of the metal layer is located between the insulating substrate and the active substance layer; wherein the metal layer comprises a conductive main body part and a conductive part extending from the conductive main body part along a first direction, the first direction is perpendicular to the thickness direction of the current collector, at least part of the conductive main body part is covered with the active material layer, at least part of the conductive part is not covered with the active material layer, and the conductive part is connected with the electrode lead-out part; in the thickness direction of the current collector, the thickness of the conductive part is larger than that of the conductive main body part.

Description

Technical Field

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

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

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

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

[0005] The purpose of the embodiments of this application is to provide a battery cell, a battery device, and an electrical device, which are beneficial to improving the fast charging performance of the battery cell.

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

[0007] In a first aspect, in some embodiments, a battery cell is provided. The battery cell includes a housing and an electrode assembly. The housing is provided with an electrode lead-out portion; at least a part of the electrode assembly is disposed inside the housing; the electrode assembly includes a first electrode plate. The first electrode plate includes a current collector and an active material layer. The current collector includes an insulating matrix and a metal layer. The insulating matrix, the metal layer, and the active material layer are stacked along the thickness direction of the current collector. At least a part of the metal layer is located between the insulating matrix and the active material layer; wherein, the metal layer includes a conductive main body portion and a conductive portion extending along a first direction from the conductive main body portion. The first direction is perpendicular to the thickness direction of the current collector. At least a part of the conductive main body portion is covered with the active material layer. At least a part of the conductive portion is not covered with the active material layer. The conductive portion is connected to the electrode lead-out portion; along the thickness direction of the current collector, the thickness of the conductive portion is greater than the thickness of the conductive main body portion.

[0008] By adopting the technical solution of this embodiment, when the battery cell is in normal use, the electrode lead-out part is used to input or output electric energy, realizing the charging and discharging of the battery cell; and the thickness of the conductive part connected to the electrode lead-out part is greater than that of the conductive main body part, increasing the current-carrying area of the conductive part, improving the current-carrying capacity of the conductive part, reducing the heat generation of the battery cell, being beneficial to improving the charge and discharge efficiency of the battery cell and the fast charging performance of the battery cell; in addition, the current collector adopts a composite structure of an insulating matrix and a metal layer. Compared with a current collector made of pure metal, the thickness of the metal layer is small, the burrs generated during the production process of the current collector are small, reducing the risk of internal short circuit of the battery cell and being beneficial to improving the use reliability of the battery cell; therefore, the battery cell of the embodiment of the present application can better balance the fast charging performance and the use reliability.

[0009] In some embodiments, the surface of the conductive part facing away from the insulating matrix is farther away from the insulating matrix than the surface of the conductive main body part facing away from the insulating matrix.

[0010] By adopting the technical solution of this embodiment, the surface of the conductive part facing away from the insulating matrix protrudes relative to the surface of the conductive main body part facing away from the insulating matrix. The side space of the conductive part facing away from the insulating matrix can be utilized, reducing the risk that the insulating matrix is thinned at the conductive part to accommodate the conductive part, improving the structural strength of the insulating matrix at the conductive part, improving the structural strength of the current collector, and improving the use reliability of the battery cell.

[0011] In some embodiments, the conductive part includes a first conductive part and a second conductive part arranged along a first direction. The first conductive part is connected between the second conductive part and the conductive main body part. The first conductive part is covered with an active material layer, the second conductive part is not covered with an active material layer, and the second conductive part is connected to the electrode lead-out part.

[0012] By adopting the technical solution of this embodiment, the active material layer covers the first conductive part, which is beneficial to improving the electron transfer ability between the active material layer and the first conductive part, reducing the resistance between the active material layer and the first conductive part, and being beneficial to improving the fast charging performance of the battery cell; in addition, the conductive main body part and the first conductive part are also covered with an active material layer, which is beneficial to improving the electron transfer ability at the junction of the first electrode plate between the first conductive part and the conductive main body part, being beneficial to reducing the resistance of the first electrode plate, and being beneficial to improving the fast charging performance of the battery cell.

[0013] In some embodiments, the active material layer includes a first active material part and a second active material part arranged along a first direction. The first active material part is connected to the second active material part. The thickness of the first active material part is less than that of the second active material part. At least part of the first active material part covers the first conductive part, and at least part of the second active material part covers the conductive main body part.

[0014] By adopting the technical solution of this embodiment, the setting of the first active material part can reduce the roller pressure on the edge of the active material layer and reduce the risk of cracking at the edge of the active material layer. In addition, at least part of the first active material part covers the first conductive part, which is beneficial to reducing the overall thickness of the first electrode sheet at the first active material part and also beneficial to reducing the edge pressure of the active material layer, further reducing the risk of cracking at the edge of the active material layer.

[0015] In some embodiments, the surface of the first active material part facing away from the insulating substrate is closer to the insulating substrate than the surface of the second active material part facing away from the insulating substrate.

[0016] By adopting the technical solution of this embodiment, the roller pressure received at the first active material part can be reduced, which is beneficial to the risk of cracking of the active material layer.

[0017] In some embodiments, the second active material part covers a part of the first conductive part, and the first active material part covers the other part of the first conductive part.

[0018] By adopting the technical solution of this embodiment, the second active material part covers the first conductive part, and there is more active material covering the first conductive part. The electron transfer ability between the first conductive part and the active material layer is better, which is beneficial to reducing the resistance between the active material layer and the first conductive part and improving the fast charging ability of the battery cell.

[0019] In some embodiments, along the first direction, the size of the part of the first conductive part covered by the second active material part is W 1 , and the size of the part of the first conductive part covered by the first active material part is W 2 , W 1 ≥W 2 .

[0020] By adopting the technical solution of this embodiment, a larger part of the first conductive part is covered by the second active material part, and a smaller part of the first conductive part is covered by the first active material part, so that there is more active material covering the first conductive part. The electron transfer ability between the first conductive part and the active material layer is better, which is beneficial to reducing the resistance between the active material layer and the first conductive part and improving the fast charging ability of the battery cell.

[0021] In some embodiments, the thickness of the conductive main body part is t 1 , the maximum thickness of the first conductive part is t 2 , and the thickness of the second active material part is t 3 , where 0.002 ≤ (t 2 - t 1 ) / t 3 ≤0.08; optionally, 0.003 ≤ (t 2 - t1 ) / t 3 ≤0.06.

[0022] By adopting the technical solution of this embodiment, the ratio of the thickness difference between the first conductive part and the conductive main body part to the thickness of the second active material part is within a reasonable range, improving the flatness of the surface of the active material layer facing away from the insulating substrate, which is beneficial to improving the manufacturability of the first electrode sheet.

[0023] In some embodiments, 60μm ≤ t 3 ≤ 250μm; optionally, 80μm ≤ t 3 ≤ 180μm.

[0024] By adopting the technical solution of this embodiment, the thickness of the second active material part is within a suitable range, and the volume of the active material layer is reasonably set, which is beneficial to improving the fast charging performance and service reliability of the battery cell, and can also reduce the risk of difficult ion extraction in the area of the active material layer close to the conductive layer, improving the performance of the battery cell.

[0025] In some embodiments, along the first direction, the size of the first conductive part is W 3 , and the size of the conductive part is W 4 , where W 3 / W 4 ≤ 0.4.

[0026] By adopting the technical solution of this embodiment, along the first direction, the ratio of the size of the first conductive part to the size of the conductive part is reasonably set, facilitating the connection between the second conductive part and the electrode lead-out part. The first conductive part and the active material layer have good electron transport ability, which is beneficial to reducing the resistance of the first electrode sheet and improving the fast charging performance of the battery cell.

[0027] In some embodiments, along the first direction, the size of the first conductive part is W 3 , and the size of the conductive part is W 4 , where 2mm ≤ W 4 -W 3 ≤ 10mm, optionally, 3mm ≤ W 4 -W 3 ≤ 6mm.

[0028] By adopting the technical solution of this embodiment, along the first direction, the size of the second conductive part is within a reasonable range, facilitating the connection between the second conductive part and the electrode lead-out part, and can also reduce the excessive space occupied due to the too large size of the second conductive part along the first direction, which is beneficial to improving the energy density of the battery cell.

[0029] In some embodiments, along the first direction, the size of the first conductive part is W 3 , and the size of the conductive main body part is W5 , wherein, W 3 / (W 3 +W 5 ) ≤ 0.45.

[0030] By adopting the technical solution of this embodiment, along the first direction, the ratio of the size of the first conductive part to the sum of the sizes of the first conductive part and the conductive main body part is within a suitable range, and the first conductive part can cover the active material layer, which is beneficial to reducing the internal resistance of the first electrode and improving the fast charging ability of the battery cell; in addition, along the second direction, the first conductive part does not occupy too much area, and the thickness of the first conductive part is greater than that of the conductive main body part, which also reduces the risk of burrs generated at the first conductive part of the first electrode, and is beneficial to improving the use reliability of the battery cell.

[0031] In some embodiments, along the first direction, the size of the first conductive part is W 3 , wherein, 10 mm ≤ W 3 ≤ 100 mm.

[0032] By adopting the technical solution of this embodiment, along the first direction, the size of the first conductive part is within a reasonable range, so that there is good electron transfer ability between the active material layer and the first conductive part. In addition, along the second direction, the first conductive part does not occupy too much area, and the thickness of the first conductive part is greater than that of the conductive main body part, which also reduces the risk of burrs generated at the first conductive part of the first electrode, and is beneficial to improving the use reliability of the battery cell.

[0033] In some embodiments, the second conductive part includes at least one protruding part, the protruding part is connected to the first conductive part, and along the second direction, the size of the protruding part is smaller than that of the conductive main body part, and the second direction is perpendicular to the thickness direction and the first direction of the current collector.

[0034] By adopting the technical solution of this embodiment, along the second direction, the size of the protruding part is smaller than that of the conductive main body part, and the protruding part is easily bent with the conductive member and connected to the electrode lead-out part, which is convenient for processing and manufacturing, and is also beneficial to reducing the space occupied after the conductive member is bent, and is beneficial to improving the energy density of the battery cell.

[0035] In some embodiments, the protruding part includes a first protruding sub-part and a second protruding sub-part, and the first protruding sub-part is connected between the second protruding sub-part and the first conductive part; along the second direction, the size of the first protruding sub-part is larger than that of the second protruding sub-part.

[0036] By adopting the technical solution of this embodiment, along the second direction, the first protruding sub-part is large, the current-carrying area of the first protruding sub-part is large and the current-carrying capacity is strong, which is beneficial to reducing heat generation and is beneficial to improving the fast charging performance and use reliability of the battery cell.

[0037] In some embodiments, the number of the protruding portions is plural, the plural protruding portions are arranged at intervals along the second direction, and along the second direction, the sum of the sizes of all the protruding portions is smaller than the size of the conductive main body portion.

[0038] By adopting the technical solution of this embodiment, the plural protruding portions are arranged at intervals along the second direction, which is beneficial to divide the conductive main body portion into plural regions along the second direction, and one region can correspond to one protruding portion. Electrons in each region can be transmitted to the electrode lead-out portion through the corresponding protruding portion, so that the electrons of the conductive main body portion are transmitted in sub-regions. The electron transmission path in each region to the corresponding protruding portion is short, which is beneficial to reducing the electron transmission distance, reducing the overall resistance of the first pole piece, and improving the fast charge performance and service reliability of the battery cell.

[0039] In some embodiments, the second conductive portion further includes a transition portion, the transition portion is connected between the protruding portion and the first conductive portion, and along the second direction, the size of the transition portion is larger than the sum of the sizes of all the protruding portions.

[0040] By adopting the technical solution of this embodiment, the thickness of the transition portion is larger than that of the conductive main body portion, and the size of the transition portion along the second direction is large, and the current-carrying capacity of the transition portion is strong, which is beneficial to reducing heat generation and improving the fast charge performance and service reliability of the battery cell.

[0041] In some embodiments, along the second direction, the size of the conductive main body portion is L 1 , and the size of the transition portion is L 2 , 0.8 ≤ L 2 / L 1 ≤ 1.

[0042] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L 2 / L 1 ≤ 1 makes the size of the transition portion close to the size of the conductive main body portion along the second direction. The size of the transition portion is large, and the current-carrying capacity of the transition portion is good, which is beneficial to reducing heat generation and improving the fast charge performance and service reliability of the battery cell.

[0043] In some embodiments, the first pole piece further includes a conductive member, the conductive member includes a first connecting portion and a second connecting portion arranged along the first direction, the first connecting portion is connected to the second connecting portion, the first connecting portion is connected to the surface of the second conductive portion facing away from the insulating matrix, and the second connecting portion is located on the side of the second conductive portion facing away from the first conductive portion, and the second connecting portion is connected to the electrode lead-out portion.

[0044] By adopting the technical solution of this embodiment, the second connecting portion protrudes outside the second conductive portion, which facilitates the connection between the second connecting portion and the electrode lead-out portion, and is more convenient for processing and manufacturing.

[0045] In some embodiments, along a first direction, the first connecting portion is spaced apart from the active material layer.

[0046] By adopting the technical solution of this embodiment, the first connecting portion does not contact the active material layer, which can reduce the mutual influence between the two and improve the reliability of use of the battery cell.

[0047] In some embodiments, the first connecting portion is welded to the surface of the second conductive portion facing away from the insulating substrate to form a first welding mark.

[0048] By adopting the technical solution of this embodiment, the first connecting portion is welded to the second conductive portion, and the conductive member is connected to the second conductive portion by welding, which is convenient for the production of the first electrode sheet; in addition, the thickness of the second conductive portion is small, and the surface of the second conductive portion facing away from the insulating substrate is large, which is beneficial to increasing the welding area between the first connecting portion and the second conductive portion, increasing the current-carrying area between the first connecting portion and the second conductive portion, beneficial to improving the current-carrying capacity of the first electrode sheet, improving the fast charging performance and reliability of use of the battery cell; at the same time, it can also reduce the risk of problems such as false soldering between the first connecting portion and the second conductive portion, beneficial to improving the connection reliability between the second conductive portion and the conductive member, and also beneficial to improving the current-carrying capacity of the first electrode sheet, improving the fast charging performance and reliability of use of the battery cell.

[0049] In some embodiments, the second conductive portion includes at least one protruding portion, the protruding portion is connected to the first conductive portion, and along a second direction, the size of the protruding portion is smaller than the size of the conductive main body portion; the second direction is perpendicular to the thickness direction of the current collector and the first direction; the first welding mark includes a first welding mark portion, and the first connecting portion is welded to the surface of the protruding portion facing away from the insulating substrate to form the first welding mark portion.

[0050] By adopting the technical solution of this embodiment, the first connecting portion and the protruding portion are connected by welding, and the connection method is simple, which is convenient for the production of the first electrode sheet; in addition, the first connecting portion and the protruding portion can directly use the first welding mark portion for current conduction, which is beneficial to improving the current-carrying capacity between the first connecting portion and the protruding portion.

[0051] In some embodiments, the protruding portion includes a first protruding sub-portion and a second protruding sub-portion, and the first protruding sub-portion is connected between the second protruding sub-portion and the first conductive 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 welding mark portion includes a first welding mark sub-portion, and the first connecting portion is welded to the first protruding sub-portion to form the first welding mark sub-portion; and / or, the first welding mark portion further includes a second welding mark sub-portion, and the first connecting portion is welded to the surface of the second protruding sub-portion facing away from the insulating substrate to form the second welding mark sub-portion.

[0052] By adopting the technical solution of this embodiment, the welding position can be set flexibly to meet different requirements.

[0053] In some embodiments, the number of the protruding portions is plural, and the plural protruding portions are arranged at intervals along the second direction; the first connecting portion includes a plurality of first connecting sub-portions, the plurality of first connecting sub-portions are arranged at intervals along the second direction, the number of the second connecting portions is plural, and each of the first connecting sub-portions is connected to each of the second connecting portions in one-to-one correspondence; each of the first connecting sub-portions is welded to the surface of each protruding portion facing away from the insulating substrate.

[0054] By adopting the technical solution of this embodiment, the plurality of first connecting sub-portions of the first connecting portion are arranged at intervals along the second direction, and there is a gap between two adjacent first connecting sub-portions, so that the material required for the first connecting portion can be reduced, and the manufacturing cost of the battery cell can be lowered.

[0055] In some embodiments, the second conductive portion includes a transition portion and at least one protruding portion, the transition portion is connected between the first conductive portion and the protruding portion, and along the second direction, the size of the transition portion is greater than the sum of the sizes of all the protruding portions; the second direction is perpendicular to the thickness direction and the first direction of the current collector; the first welding mark further includes a second welding mark portion, and the first connecting portion is welded to the surface of the transition portion facing away from the insulating substrate to form the second welding mark portion.

[0056] By adopting the technical solution of this embodiment, the first connecting portion and the transition portion are connected by welding, and the connection method is simple, which is beneficial to the production of the first pole piece; in addition, along the second direction, the size of the transition portion is large, and the current-carrying capacity of the transition portion is good. The first connecting portion and the first conductive portion can directly use the transition portion for current conduction, so that the current-carrying pressure between the protruding portion and the current-carrying portion can be reduced, and even the protruding portion does not need to conduct current, reducing the heat generation risk and being beneficial to improving the fast charging performance of the battery cell.

[0057] In some embodiments, along the second direction, the size of the transition portion is L 2 , and the size of the second welding mark portion is L 3 , 0.8 ≤ L 3 / L 2 ≤ 1.

[0058] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L 3 / L 2 ≤ 1 makes the size of the second welding mark portion larger along the second direction, which is beneficial to increasing the welding area between the first connecting portion and the transition portion, improving the current-carrying capacity at the connection between the first connecting portion and the transition portion, improving the current-carrying capacity of the first pole piece, and improving the fast charging performance and service reliability of the battery cell.

[0059] In some embodiments, the number of protruding portions is plural, and the plural protruding portions are arranged at intervals in the second direction; the first connecting portion includes a second connecting sub-portion and plural first connecting sub-portions, the plural first connecting sub-portions are arranged at intervals in the second direction, and each first connecting sub-portion correspondingly covers each protruding portion; the number of the second connecting portions is plural, and along the first direction, one side of each first connecting sub-portion is correspondingly connected to each second connecting portion, the other side of each first connecting sub-portion is connected to the second connecting sub-portion, and the second connecting sub-portion is continuously arranged in the second direction; the second connecting sub-portion is welded to the surface of the transition portion facing away from the insulating substrate.

[0060] By adopting the technical solution of this embodiment, the second connecting sub-portion is continuously arranged in the second direction, and the plural first connecting sub-portions can be connected into a whole. The second connecting sub-portion can play a good supporting role for the first connecting sub-portions, can reduce the risk of the first connecting sub-portions being bent when inserted between the first pole piece and the second pole piece, reduce the risk of short circuit, and is beneficial to improving the use reliability of the battery cell; in addition, along the second direction, the size of the second connecting sub-portion is large, which is beneficial to increasing the welding area between the second connecting sub-portion and the transition portion, beneficial to improving the current-carrying capacity at the connection between the first connecting portion and the transition portion, improving the current-carrying capacity of the first pole piece, and improving the fast charging performance and use reliability of the battery cell.

[0061] In some embodiments, the electrode assembly further includes an insulating member, and the insulating member includes a first insulating portion that covers the surface of the second conductive portion facing away from the insulating substrate, and the entire first insulating portion is located between the first welding mark and the active material layer.

[0062] By adopting the technical solution of this embodiment, the first insulating portion can insulate and separate the surface of the second conductive portion facing away from the insulating substrate from other components, which is beneficial to improving the use reliability of the battery cell, and is also beneficial to reducing the risk of false soldering caused by the first connecting portion being soldered to the first insulating portion, improving the connection reliability between the first connecting portion and the second conductive portion, and is also beneficial to improving the current-carrying capacity.

[0063] In some embodiments, the first insulating portion is located between the first connecting portion and the active material layer.

[0064] By adopting the technical solution of this embodiment, the first insulating portion can support the part of the second conductive portion located between the first connecting portion and the active material layer, can reduce damages such as cracks and fractures that occur in this part during the manufacturing process of the battery device, is beneficial to improving the electron transport ability of this part, improving the fast charging performance and use reliability of the battery cell; in addition, the first insulating portion can also insulate this part, reduce the short circuit risk of the battery cell, and improve the use reliability of the battery cell.

[0065] In some embodiments, the insulating member further includes a second insulating portion, and at least part of the second insulating portion covers the first welding mark.

[0066] By adopting the technical solution of this embodiment, components such as tip protrusions and metal debris will be generated on the surface of the first welding mark. The second insulating portion covers the surface of the first welding mark, which can prevent the tip protrusions and metal debris from contacting the second pole piece, reduce the short-circuit risk of the battery cell, and improve the service reliability of the battery cell.

[0067] In some embodiments, along the first direction, one side of the second insulating portion covers the first welding mark, and the other side of the second insulating portion covers at least part of the first insulating portion.

[0068] By adopting the technical solution of this embodiment, the second insulating portion and the first insulating portion jointly cover the second conductive portion, which can achieve double-layer insulation, is beneficial to reducing the short-circuit risk of the battery cell, and is beneficial to improving the service reliability of the battery cell.

[0069] In some embodiments, the electrode assembly further includes an insulating member, the insulating member includes a second insulating portion, and at least part of the second insulating portion covers the first welding mark.

[0070] By adopting the technical solution of this embodiment, components such as tip protrusions and metal debris will be generated on the surface of the first welding mark. The second insulating portion covers the surface of the first welding mark, which can prevent the tip protrusions and metal debris from contacting the second pole piece, reduce the short-circuit risk of the battery cell, and improve the service reliability of the battery cell.

[0071] In some embodiments, along the first direction, one side of the second insulating portion covers the first welding mark, and the other side of the second insulating portion covers at least part of the active material layer.

[0072] By adopting the technical solution of this embodiment, the second insulating portion extends from the first welding mark to the active material layer, and the covering area of the second insulating portion is wide and the insulation effect is good.

[0073] In some embodiments, the number of metal layers is two, the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector, the number of active material layers is two, and the two active material layers respectively cover the two metal layers; the number of conductive members is two, the first connection parts of the two conductive members are respectively welded to the second conductive parts of the two metal layers to form two first welding marks; the number of insulating members is two, and the second insulating portions of the two insulating members respectively cover at least part of the two first welding marks.

[0074] By adopting the technical solution of this embodiment, the first connection parts of the two conductive members are respectively welded to the metal layers on the opposite sides of the insulating matrix, and the second connection parts of the two conductive members are located on the side of the second conductive part facing away from the first conductive part. In this way, the two conductive parts can be directly connected by using the second connection parts of the two conductive members, thereby breaking the insulation limitation of the insulating matrix, effectively improving the conductivity of the first electrode plate, improving the fast charging performance of the battery cell, reducing heat generation, and improving the reliability of the battery cell in use. Metal layer.

[0075] In some embodiments, the second insulating part includes a first part and a second part connected to each other. The first part covers the first welding mark. Along the direction from the conductive main body part to the conductive part, the second part protrudes from the side surface of the second conductive part. The second part is located on the side of the second connection part along the second direction, where the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0076] By adopting the technical solution of this embodiment, along the direction from the conductive main body part to the conductive part, components such as metal debris at the side of the second conductive part away from the active material layer can be located between the second parts of the two insulating parts. In this way, the risk of metal debris falling into the electrode assembly can be reduced, which is beneficial to reducing the risk of short circuit.

[0077] In some embodiments, the second parts of the two insulating parts are attached to each other.

[0078] By adopting the technical solution of this embodiment, after the second parts of the two insulating parts are attached to each other, components such as metal debris at the side of the second conductive part can be wrapped, making it not easy for components such as metal debris to fall into the electrode assembly, and better reducing the short circuit risk of the battery cell.

[0079] In some embodiments, along the direction from the conductive main body part towards the conductive part, the second connection parts of the two conductive members are welded to form a second welding mark.

[0080] By adopting the technical solution of this embodiment, after the second connection parts of the two conductive members are welded, the second conductive parts on the opposite sides of the insulating matrix can be connected, thereby breaking the insulation limitation of the insulating matrix, effectively improving the conductivity of the first electrode plate, improving the fast charging performance of the battery cell, reducing heat generation, and improving the reliability of the battery cell in use. Metal layer.

[0081] In some embodiments, the second insulating part covers the second welding mark. Along the direction from the conductive main body part to the conductive part, the second insulating part protrudes from the edge of the second welding mark facing away from the conductive main body part.

[0082] By adopting the technical solution of this embodiment, the second insulating part can completely cover the second welding mark, preventing components such as burrs and metal debris on the second welding mark from piercing through the separator and connecting to the second electrode plate, reducing the short circuit risk, and improving the reliability of the battery cell in use.

[0083] In some embodiments, the electrode assembly includes a second electrode tab having a polarity opposite to that of the first electrode tab. The second electrode tab includes a main functional portion and an electrode ear portion, and the electrode ear portion protrudes from the main functional portion in a first direction; along the direction from the conductive main portion to the conductive portion, the main functional portion protrudes from the end face of the insulating member facing the active material layer, and the main functional portion does not protrude from the end face of the insulating member away from the active material layer.

[0084] By adopting the technical solution of this embodiment, the insulating member can prevent the burrs at the end face of the main functional portion of the second electrode tab near the electrode ear portion from piercing through the separator and connecting to the first electrode tab, reducing the short-circuit risk between the first electrode tab and the second electrode tab, and being beneficial to improving the usage reliability of the battery cell.

[0085] In some embodiments, the electrode assembly includes a second electrode tab having a polarity opposite to that of the first electrode tab. The second electrode tab includes a main functional portion and an electrode ear portion, and the electrode ear portion protrudes from the main functional portion in a first direction; along the direction from the conductive main portion to the conductive portion, the main functional portion protrudes from the end face of the conductive portion facing away from the conductive main portion.

[0086] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional portion of the second electrode tab facing the electrode ear portion correspond to the hollowed-out area where the metal layer does not extend beyond the second connection portion, which can also reduce the short-circuit risk of the battery cell and improve the usage reliability of the battery cell.

[0087] In some embodiments, along the first direction, the size of the portion of the insulating member covering the active material layer is H, where 0.2 mm ≤ H ≤ 1.0 mm, and optionally, 0.3 mm ≤ H ≤ 0.8 mm.

[0088] By adopting the technical solution of this embodiment, along the first direction, the size of the portion of the insulating member covering the active material layer is reasonable, which can take into account both blocking the burrs at the end of the active material layer near the conductive portion and the energy density of the battery cell.

[0089] In some embodiments, along the first direction, the distance between the first welding mark and the active material layer is W, where 0.5 mm ≤ S 1 ≤ 5 mm, and optionally, 0.5 mm ≤ S 1 ≤ 2.8 mm.

[0090] By adopting the technical solution of this embodiment, the first welding mark will not be welded to the active material layer, reducing problems such as false soldering, which is beneficial to improving the connection reliability between the first connection portion and the metal layer. In addition, the distance between the active material layer and the first welding mark is small, and the active material layer can be relatively close to the first welding mark. Then, when the size of the metal layer in the first direction is fixed, the area that the active material layer can cover is larger, which is beneficial to improving the energy density of the battery cell.

[0091] In some embodiments, along the first direction, the distance between the first welding mark and the end face of the first connecting portion facing the active material layer is S 2 , where 0.3 mm ≤ S 2 ≤ 1.2 mm.

[0092] By adopting the technical solution of this embodiment, the use reliability and energy density of the battery cell can be better balanced.

[0093] In some embodiments, along the first direction, the size of the conductive portion is W 4 , and the size of the conductive main body portion is W 5 , where 0.01 ≤ W 4 / W 5 ≤ 0.8; optionally, 0.05 ≤ W 4 / W 5 ≤ 0.6.

[0094] By adopting the technical solution of this embodiment, the ratio of the size of the conductive portion to the size of the conductive main body portion along the first direction is reasonably set, which can improve the overcurrent capacity at the conductive portion, improve the fast charging performance and use reliability of the battery cell. In addition, along the first direction, the size of the conductive portion is not too large, which is beneficial to reducing the occupied space and weight of the conductive portion and improving the energy density of the battery cell.

[0095] In some embodiments, the thickness of the conductive main body portion is t 1 , and the maximum thickness of the conductive portion is t 4 , where 0.2 μm ≤ t 4 -t 1 ≤ 4.5 μm, optionally, 0.3 μm ≤ t 4 -t 1 ≤ 1.75 μm.

[0096] By adopting the technical solution of this embodiment, the difference between the maximum thickness of the conductive portion and the thickness of the conductive main body portion is within a reasonable range, which can improve the overcurrent capacity at the conductive portion, improve the fast charging performance and use reliability of the battery cell. In addition, the thickness of the conductive portion is not too large, which is beneficial to reducing the occupied space and weight of the conductive portion and improving the energy density of the battery cell.

[0097] In some embodiments, the thickness of the conductive main body portion is t 1 , and the maximum thickness of the conductive portion is t 4 , where 1 < t 1 / t 4 ≤ 4, optionally, 1.5 < t 1 / t 4 ≤ 2.5.

[0098] By adopting the technical solution of this embodiment, the ratio of the maximum thickness of the conductive part to the thickness of the conductive main body part is within a reasonable range, which can improve the over-current capacity at the conductive part, improve the fast charging performance and service reliability of the battery cell. In addition, the thickness of the conductive part is not too large, which is beneficial to reducing the occupied space and weight of the conductive part and improving the energy density of the battery cell.

[0099] In some embodiments, the thickness of the conductive part is t 4 , where 1μm ≤ t 4 ≤ 5μm. Optionally, 1.2μm ≤ t 4 ≤ 3.5μm.

[0100] By adopting the technical solution of this embodiment, the thickness of the conductive part is reasonably designed, which can improve the over-current capacity at the conductive part, improve the fast charging performance and service reliability of the battery cell. In addition, the thickness of the conductive part is not too large, which is beneficial to reducing the occupied space and weight of the conductive part and improving the energy density of the battery cell.

[0101] In some embodiments, the conductive part includes a first main body section and a first transition section. The first transition section is connected between the first main body section and the conductive main body part. The thickness of the first transition section is greater than that of the conductive main body part; the thickness of the first main body section is greater than that of the first transition section; at least part of the first transition section is covered with an active material layer.

[0102] By adopting the technical solution of this embodiment, the setting of the first transition section can reduce the stress concentration of the metal layer, reduce the risk of cracks appearing during the forming process of the metal layer, improve the over-current capacity of the conductive part, improve the fast charging performance and service reliability of the battery cell, and also facilitate processing and manufacturing.

[0103] In some embodiments, along the direction from the conductive main body part to the conductive part, the thickness of the first transition section is set to increase.

[0104] By adopting the technical solution of this embodiment, the stress concentration of the metal layer can be better reduced, the risk of cracks appearing during the forming process of the metal layer can be better reduced, the over-current capacity of the conductive part can be improved, the fast charging performance and service reliability of the battery cell can be improved, and it is also convenient for processing and manufacturing.

[0105] In some embodiments, along the first direction, the size of the first transition section is W 6 , where 4mm ≤ W 6 ≤ 50mm. Optionally, 5mm ≤ W 6 ≤ 34mm.

[0106] By adopting the technical solution of this embodiment, the size of the first transition section in the first direction is reasonably designed, which can reduce the stress concentration of the metal layer, reduce the risk of cracks occurring during the forming process of the metal layer, improve the current-carrying capacity of the conductive part, enhance the fast charging performance and service reliability of the battery cell, and is also convenient for processing and manufacturing. In addition, the size of the first transition section in the first direction is not too large, reducing the space and weight occupied by the conductive part, which is beneficial to improving the energy density of the battery cell.

[0107] In some embodiments, the first electrode sheet further includes a conductive protective layer, and at least part of the conductive protective layer is located between the active material layer and the metal layer.

[0108] By adopting the technical solution of this embodiment, the conductive protective layer can separate the active material layer and the metal layer and at the same time play a protective role for the metal layer, reducing the cracks generated by rolling the metal layer, which is beneficial to improving the current-carrying capacity of the metal layer.

[0109] In some embodiments, along the direction from the conductive main body part to the conductive part, the protruding distance range of the conductive protective layer protruding from the end face of the active material layer facing the protruding part is 0.3 mm to 0.8 mm.

[0110] By adopting the technical solution of this embodiment, the current-carrying capacity and energy density of the battery cell can be better balanced.

[0111] In some embodiments, the conductive protective layer includes a first protective part and a second protective part. The first protective part covers the conductive main body part, and the second protective part covers at least part of the conductive part; wherein, the thickness of the second protective part is less than the thickness of the first protective part.

[0112] By adopting the technical solution of this embodiment, the thickness of the second protective part is less than the thickness of the first protective part, which is beneficial to reducing the sum of the thicknesses of the first protective part and the conductive main body part approaching the sum of the thicknesses of the second protective part and the conductive part, and is beneficial to the surface of the conductive protective part facing away from the metal layer approaching a plane, thereby being beneficial to reducing rolling damage and improving the current-carrying capacity of the metal layer; in addition, it can also reduce the problem of winding bulging of the current collector.

[0113] In some embodiments, the conductive part includes a first main body section and a first transition section. The first transition section is connected between the first main body section and the conductive main body part, and the thickness of the first transition section is greater than the thickness of the conductive main body part; the thickness of the first main body section is greater than the thickness of the first transition section; the second protective part includes a second main body section and a second transition section. The second transition section covers the first transition section, and the second main body section covers at least part of the first main body section. The thickness of the second transition section is less than the thickness of the first protective part; the thickness of the second main body section is less than the thickness of the second transition section.

[0114] By adopting the technical solution of this embodiment, the thickness change of the second protection part can compensate for the thickness change of the conductive part, which is beneficial to the surface of the second protection part facing away from the metal layer approaching a plane, beneficial to reducing rolling damage, and improving the current-carrying capacity of the metal layer; in addition, the problem of winding bulging of the current collector can also be reduced.

[0115] In some embodiments, along the direction from the conductive main body part to the conductive part, the thickness of the first transition section is set to increase, and the thickness of the second transition section is set to decrease.

[0116] By adopting the technical solution of this embodiment, the thickness change of the second protection part is adapted to the thickness of the conductive part, and the thickness change of the second protection part better compensates for the thickness change of the conductive part, which is more beneficial to the surface of the second protection part facing away from the metal layer approaching a plane, beneficial to reducing rolling damage, and improving the current-carrying capacity of the metal layer.

[0117] In some embodiments, the thickness of the second main body section is t 5 , and the thickness of the first protection part is t 6 , where 0.03 ≤ t 5 / t 6 ≤ 0.95. Optionally, 0.125 ≤ t 5 / t 6 ≤ 0.8.

[0118] By adopting the technical solution of this embodiment, the ratio of the thickness of the second main body section to the thickness of the first protection part is within a reasonable range, the degree of thinning of the conductive protection layer is reasonable, and it can be better adapted to the degree of thickening of the conductive part, which is beneficial to the surface of the second protection part facing away from the metal layer approaching a plane, beneficial to reducing rolling damage, and improving the current-carrying capacity of the metal layer.

[0119] In some embodiments, the thickness of the second main body section is t 5 , where 0.5 μm ≤ t 5 ≤ 4 μm. Optionally, 1 μm ≤ t 5 ≤ 2 μm.

[0120] By adopting the technical solution of this embodiment, the thickness of the second main body section is set reasonably, which can reduce the risk of cracking of the metal layer; in addition, it will not cause the second main body section to protrude from the first protection part due to the second main body section being too thick, and it can also reduce material accumulation and reduce manufacturing costs.

[0121] In some embodiments, the insulating substrate includes a first insulating base and a second insulating base. The conductive main body part covers the first insulating base, and the conductive part covers the second insulating base; the thickness of the conductive main body part is t 1 , the thickness of the conductive part is t 4 , and the thickness of the first protection part is t 6, the minimum thickness of the second protection part is t 7 , the thickness of the first insulating base is t 8 , the thickness of the second insulating base is t 9 , where, -4μm ≤ (t 1 + t 6 + t 8 / 2) - (t 4 + t 7 + t 9 / 2) ≤ 4μm, optionally, -2μm ≤ (t 1 + t 6 + t 8 / 2) - (t 2 + t 7 + t 8 / 2) ≤ 2μm.

[0122] By adopting the technical solution of this embodiment, the design of -4μm ≤ (t 1 + t 6 + t 8 / 2) - (t 4 + t 7 + t 9 / 2) ≤ 4μm makes the difference in the half thickness of the current collector at the conductive main body part and the half thickness of the current collector at the conductive part not large, which is beneficial to the surface of the conductive protection layer facing away from the metal layer being close to a plane, beneficial to reducing roll pressing damage, and improving the over-current capacity of the metal layer; in addition, it can also reduce the edge bulging of the electrode assembly.

[0123] In some embodiments, the thickness of the second insulating base is less than the thickness of the first insulating base.

[0124] By adopting the technical solution of this embodiment, the thickness of the second insulating base is less than the thickness of the first insulating base, making the sum of the thickness of the second insulating base and the conductive part close to the sum of the thickness of the first insulating base and the conductive main body part, which is beneficial to the surface of the metal layer facing away from the insulating matrix being close to a plane, beneficial to reducing roll pressing damage, and improving the over-current capacity of the metal layer.

[0125] In some embodiments, the outer shell includes a housing and an end cap. The end cap is disposed at the opening of the housing, and the housing and the end cap enclose to form a receiving cavity. The electrode assembly is received in the receiving cavity, and at least one of the housing and the end cap is provided with an electrode lead-out part.

[0126] By adopting the technical solution of this embodiment, the outer shell adopts the structure of the end cap and the housing, and the electrode assembly is easily loaded into the outer shell, which is convenient for the assembly of the battery cell and beneficial to reducing the manufacturing cost.

[0127] In some embodiments, the capacity of the battery cell is greater than or equal to 20 A·h.

[0128] By adopting the technical solution of this embodiment, the metal layer adopts a thickened structure of the conductive part, which can better meet the usage requirements that the capacity of the battery cell is greater than or equal to 20 A·h.

[0129] In some embodiments, the first electrode sheet is a positive electrode sheet, and the active material of the active material layer contains Ni element.

[0130] By adopting the technical solution of this embodiment, the active material of the active material layer contains Ni (nickel) element, which can improve the energy density of the battery cell. In addition, the positive electrode sheet adopts the structure of the above-mentioned first electrode sheet, and the current collector of the first electrode sheet adopts the structure of a composite current collector, which can reduce the risk of internal short circuit of the battery cell and reduce the risk of thermal runaway of the battery cell.

[0131] In some embodiments, the material of the metal layer includes one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0132] By adopting the technical solution of this embodiment, the metal layer adopts the above materials, which is beneficial to improving the performance of the battery cell.

[0133] In a second aspect, a battery device is provided, including the battery cell of the above embodiment.

[0134] The battery device of the embodiment of the present application adopts the above battery cell. The fast charging performance and usage reliability of the battery cell are good, which is beneficial to improving the fast charging performance and usage reliability of the battery device, and is also beneficial to improving the usage reliability of the battery device.

[0135] In a third aspect, an electrical device is provided, including the battery device of the above embodiment.

[0136] The electrical device of the embodiment of the present application adopts the above battery device. The fast charging performance and usage reliability of the battery device are good, which is beneficial to improving the endurance of the electrical device and is also beneficial to improving the usage reliability of the electrical device.

[0137] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically listed below. Description of the Drawings

[0138] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0139] Figure 1 Structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0140] Figure 2 Exploded schematic diagram of a battery device provided by some embodiments of the present application.

[0141] Figure 3 Exploded schematic diagram of a battery cell provided by some embodiments of the present application.

[0142] Figure 4 Structural schematic diagram of an electrode assembly provided by some embodiments of the present application.

[0143] Figure 5 Along Figure 4 Sectional view taken along line A-A in

[0144] Figure 6 Structural schematic diagram of a first pole piece provided by some embodiments of the present application.

[0145] Figure 7 Along Figure 6 Sectional view taken along line B-B in

[0146] Figure 8 For Figure 6 Partial enlarged view at C in

[0147] Figure 9 Structural schematic diagram of the first pole piece after hiding the conductive member provided by some embodiments of the present application.

[0148] Figure 10 For Figure 9 Partial enlarged view at D in

[0149] Figure 11 Structural schematic diagram of a first pole piece provided by some other embodiments of the present application.

[0150] Figure 12 For Figure 11 Partial enlarged view at E in

[0151] Figure 13 For Figure 11 Structural schematic diagram of the first pole piece after hiding the conductive member shown in

[0152] Figure 14 ForFigure 13 Partial enlarged view at F in the figure.

[0153] Figure 15 Schematic structural diagram of the first pole piece provided by some other embodiments of the present application.

[0154] Figure 16 Along Figure 15 Sectional view taken along line H-H in the figure.

[0155] Figure 17 Along Figure 15 Sectional view taken along line I-I in the figure.

[0156] Figure 18 Schematic structural diagram of the first pole piece provided by some other embodiments of the present application.

[0157] Figure 19 For Figure 18 Partial enlarged view at J in the figure.

[0158] Figure 20 Schematic structural diagram of the first pole piece provided by some other embodiments of the present application.

[0159] Figure 21 Along Figure 20 Sectional view taken along line K-K in the figure.

[0160] Figure 22 Schematic structural diagram of the second insulating part provided by some embodiments of the present application.

[0161] Figure 23 Along Figure 22 Sectional view taken along line N-N in the figure.

[0162] Wherein, each reference numeral in the figure:

[0163] 1000, Vehicle; 1100, Battery device; 1200, Controller; 1300, Motor; 100, Battery cell; 101, Electrode assembly; 1, First electrode tab; 10, Current collector; 11, Insulating substrate; 111, First insulating base; 112, Second insulating base; 12, Metal layer; 13, Conductive main body portion; 14, Conductive portion; 141, First conductive portion; 142, Second conductive portion; 1421, Protrusion; 14211, First protruding sub-portion; 14212, Second protruding sub-portion; 1422, Transition portion; 143, First main body segment; 144, First transition segment; 20, Active material layer; 21, First active material portion; 22, Second active material portion; 30, Conductive member; 31, First connection portion; 311, First connection sub-portion; 312, Second connection sub-portion; 32, Second connection portion; 40, Insulating member; 41, First insulating portion; 42, Second insulating portion; 421, First part; 422, Second part; 423, Insulating base layer; 424, Adhesive layer; 51, First welding mark; 511, First welding mark portion; 5111, First welding mark sub-portion; 5112, Second welding mark sub-portion; 512, Second welding mark portion; 52, Second welding mark; 60, Conductive protective layer; 61, First protective portion; 62, Second protective portion; 621, Second main body segment; 622, Second transition segment; 2, Second electrode tab; 210, Main body functional portion; 220, Tab portion; 3, Separator; 200, Outer shell; 201, End cover; 202, Housing; 2011, Electrode lead-out portion; 300, Box body; 301, First box body portion; 302, Second box body portion. Detailed implementation manners

[0164] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the following further details the present application in conjunction with the Figures 1 - 23 accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0165] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above accompanying drawings are intended to cover non-exclusive inclusion.

[0166] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0167] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0168] In the description of the embodiments of the present application, the term "plural" means two or more (including two). Similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces). The meaning of "several" is one or more, unless otherwise specifically defined.

[0169] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the embodiments of the present application.

[0170] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may also be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0171] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0172] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue to be used.

[0173] The battery cell can include, but is not limited to, lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium-metal battery cells, sodium-metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-metal hydride battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0174] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a multi-prismatic battery cell, and the multi-prismatic battery cell is, for example, a hexagonal-prismatic battery cell, etc.

[0175] The battery device mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0176] In some embodiments, the battery device can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0177] In some embodiments, the battery device can be a battery pack, which includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0178] In some embodiments, the box body can be a part of the chassis structure of a vehicle. For example, a part of the box body can become at least a part of the floor of the vehicle, or a part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0179] In some embodiments, the battery device can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0180] The battery cell generally includes an electrode assembly and a housing, and the electrode assembly is accommodated in the housing. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode.

[0181] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode, which can prevent the short circuit between the positive and negative electrodes and allow active ions to pass through.

[0182] The outer casing is used to encapsulate components such as the electrode assembly and the electrolyte. The outer casing can be a steel casing, an aluminum casing, a plastic casing (such as polypropylene), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc.

[0183] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The negative electrode can be a negative electrode sheet, which can include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0184] The current collector (positive electrode current collector or negative electrode current collector) is usually made of a metal material, such as metal aluminum foil and metal copper foil. However, pure metal foils are prone to generating metal burrs, and the burrs penetrate the separator, resulting in an internal short circuit, posing a great risk of fire and explosion for the battery cell.

[0185] In order to reduce the short circuit risk inside the battery cell, 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 relatively small (for example: between several hundred nanometers and several micrometers), so that during the process of foreign objects piercing the electrode sheet, the burrs generated by the metal layer are smaller and not easily penetrate the separator. Among them, the metal layer is connected to the electrode lead-out part on the outer casing for outputting or inputting the electric energy of the battery cell. However, due to the small thickness of the metal layer, the cross-sectional area of the connection part between the metal layer and the electrode outflow part is small, resulting in poor current-carrying capacity of the connection part between the metal layer and the electrode outflow part, which is not conducive to improving the fast charging performance of the battery cell.

[0186] Based on this, the embodiments of the present application provide a technical solution. By designing the metal layer into a structure with inconsistent thickness, that is, the thickness of the conductive part connected to the electrode lead-out part is greater than the thickness of the conductive main body part. By increasing the thickness of the conductive part, it is beneficial to increase the current-carrying area of the conductive part, improve the current-carrying capacity of the conductive part, enhance the current-carrying capacity of the metal layer, reduce the heat generation of the battery cell, and is beneficial to improving the charge and discharge efficiency of the battery cell and the fast charging performance of the battery cell.

[0187] The electrode assembly described in the embodiments of the present application is applicable to battery cells, battery devices, and electrical devices using battery devices.

[0188] The battery device disclosed in the embodiments of the present application can be used in electrical devices that use the battery device as a power source or various energy storage systems that use the battery device as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spaceship, and the like.

[0189] For the convenience of description, the following embodiments will be described by taking the electrical device as a vehicle as an example.

[0190] As Figure 1 shown, a battery device 1100 is disposed inside the vehicle 1000, and the battery device 1100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery device 1100 can be used to supply power to the vehicle 1000. For example, the battery device 1100 can be used as an operating power source for the vehicle 1000.

[0191] The vehicle 1000 may further include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0192] In some embodiments of the present application, the battery device 1100 can not only be used as an operating power source for the vehicle 1000, but also be used as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0193] As Figure 2 shown, the battery device 1100 includes a box body 300 and battery cells 100, and the battery cells 100 are accommodated in the box body 300.

[0194] The housing 300 is used to accommodate the battery cells 100, and the housing 300 can have various structures. In some embodiments, the housing 300 can include a first housing part 301 and a second housing part 302. The first housing part 301 and the second housing part 302 cover each other, and the first housing part 301 and the second housing part 302 jointly define a receiving space for accommodating the battery cells 100. The second housing part 302 can be a hollow structure with one end open, and the first housing part 301 is a plate-like structure. The first housing part 301 covers the open side of the second housing part 302 to form the housing 300 with a receiving space; both the first housing part 301 and the second housing part 302 can also be hollow structures with one side open, and the open side of the first housing part 301 covers the open side of the second housing part 302 to form the housing 300 with a receiving space. Of course, the first housing part 301 and the second housing part 302 can have various shapes, such as a cylinder, a cuboid, etc.

[0195] To improve the sealing performance after the connection between the first housing part 301 and the second housing part 302, a sealing member, such as sealant, sealing ring, etc., can also be provided between the first housing part 301 and the second housing part 302.

[0196] Assuming that the first housing part 301 covers the top of the second housing part 302, the first housing part 301 can also be called the upper cover, and the second housing part 302 can also be called the lower housing.

[0197] In the battery device 1100, there can be one or multiple battery cells 100. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, in parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 100.

[0198] The multiple battery cells 100 can be directly connected in series, in parallel, or in a mixed connection together, and then the whole formed by the multiple battery cells 100 is accommodated in the housing 300; of course, it can also be that multiple battery cells 100 are first connected in series, in parallel, or in a mixed connection to form battery modules, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole and are accommodated in the housing 300.

[0199] Exemplarily, the battery cell 100 can be the smallest unit that makes up the battery device 1100.

[0200] Such as Figure 3As shown, in some embodiments, the battery cell 100 includes a housing 200 and an electrode assembly 101 accommodated in the housing 200. The electrode assembly 101 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 100, active ions (such as lithium ions) are inserted into and extracted from between the positive electrode and the negative electrode back and forth. Optionally, the electrode assembly 101 further includes a separator 3 disposed between the positive electrode and the negative electrode. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes and allow active ions to pass through at the same time.

[0201] The housing 200 is used to encapsulate components such as the electrode assembly 101 and the electrolyte.

[0202] In some embodiments, the housing 200 includes a housing body 202 and an end cap 201. The housing body 202 has an opening, and the end cap 201 is used to cover the opening.

[0203] The housing body 202 is a component for cooperating with the end cap 201 to form an internal cavity of the battery cell 100. The formed internal cavity can be used to accommodate the electrode assembly 101, the electrolyte, and other components.

[0204] The housing body 202 and the end cap 201 can be independent components. Exemplarily, an opening can be provided on the housing body 202, and the end cap 201 is covered at the opening to form an internal cavity of the battery cell 100.

[0205] The housing body 202 can be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing body 202 can be determined according to the specific shape and size of the electrode assembly 101. The material of the housing body 202 can be various. For example, the material of the housing body 202 includes but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum plastic film, steel plastic film, etc.

[0206] The shape of the end cap 201 can be adapted to the shape of the housing body 202 to cooperate with the housing body 202. The material of the end cap 201 can be the same as or different from the material of the housing body 202. Optionally, the end cap 201 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 201 is not easily deformed when being squeezed or collided, enabling the battery cell 100 to have higher structural strength and improved reliability.

[0207] The end cap 201 is connected to the housing body 202 by welding, bonding, clamping or other means.

[0208] The housing 202 can be open at one end or both ends. In some examples, the housing 202 can be a structure with an opening on one side, and the end cap 201 is provided as one and covers the housing 202. In other examples, the housing 202 can also be a structure with openings on both sides, and the end caps 201 are provided as two, and the two end caps 201 respectively cover the two openings of the housing 202.

[0209] In some embodiments, the battery cell 100 includes electrode lead-out portions 2011. The number of the electrode lead-out portions 2011 is two, one of which is connected to the positive electrode plate and the other is connected to the negative electrode plate for outputting or inputting the electric energy of the battery cell 100.

[0210] In some embodiments, the battery cell 100 further includes an electrolyte accommodated in the outer shell 200. The electrolyte functions to conduct ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like or solid.

[0211] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0212] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0213] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0214] The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0215] In some embodiments, the gel-like electrolyte includes a polymer as the skeleton network of the electrolyte, combined with an ionic liquid-lithium salt.

[0216] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0217] As an example, the polymer solid electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single-ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0218] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorus sulfur, argyrodite), amorphous sulfide), and one or more of a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0219] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to the polymer solid electrolyte.

[0220] Referring to Figure 4 and Figure 5 , the electrode assembly 101 of the embodiment of the present application includes a first pole piece 1 and a second pole piece 2 with opposite polarities.

[0221] Exemplarily, one of the first pole piece 1 and the second pole piece 2 is a positive electrode piece, and the other is a negative electrode piece.

[0222] In some embodiments, the positive electrode piece may include a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector.

[0223] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material layer is provided on any one or both of the two opposite surfaces of the positive electrode current collector.

[0224] As an example, the positive electrode current collector can be made of carbon, metal foil, or composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, titanium, aluminum or stainless steel with silver surface treatment, etc. can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0225] As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. Other conventional materials that can be used as the positive electrode active material layer of the battery device 1100 can also be used for the positive electrode active material. 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, lithium iron phosphate (such as LiFePO 4 (which can also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite material of lithium manganese iron phosphate and carbon, etc. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (which can also be abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (which can also be abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (which can also be abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (which can also be abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (which can also be abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 AL 0.05 O 2 ) and their modified compounds, etc.

[0226] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector.

[0227] As an example, the negative electrode current collector can be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrodes, nickel, or titanium, etc. can be used. The foam metal can be nickel foam, copper foam, aluminum foam, foam alloy, or foam carbon, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0228] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material can be the negative electrode active material known in the art for the battery cell 100. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials can include at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials can include at least one of elemental tin, tin oxides, and tin alloys. The negative electrode active material of the present application can also use other conventional materials that can be used as the negative electrode active material of the battery device 1100. These negative electrode active materials can be used alone or in combination of two or more.

[0229] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0230] In some embodiments, the electrode assembly 101 further includes a separator 3, and the separator 3 is used to separate the first electrode sheet 1 and the second electrode sheet 2. The separator 3 can reduce the risk of short circuit between the positive and negative electrodes, and at the same time allow active ions to pass through.

[0231] In some embodiments, the separator 3 includes a separator membrane. The separator membrane of the present application can be any known porous structure separator membrane with good chemical stability and mechanical stability.

[0232] As an example, the main materials of the separator membrane can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator membrane can be a single-layer film or a multi-layer composite film. When the separator membrane is a multi-layer composite film, the materials of each layer can be the same or different. The separator 3 can be a separate component located between the positive and negative electrodes, or can be attached to the surfaces of the positive and negative electrodes.

[0233] In some embodiments, the separator 3 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet, and at the same time plays the role of transporting ions and isolating the positive and negative electrodes.

[0234] In some embodiments, the electrode assembly 101 has a wound structure. Exemplarily, both the first electrode tab 1 and the second electrode tab 2 are strip-shaped structures, and the first electrode tab 1, the separator 3, and the second electrode tab 2 are wound into a wound structure.

[0235] In some embodiments, the electrode assembly 101 has a stacked structure.

[0236] As an example, multiple first electrode tabs 1 and multiple second electrode tabs 2 may be respectively provided, and the multiple first electrode tabs 1 and the multiple second electrode tabs 2 are alternately stacked.

[0237] As an example, multiple first electrode tabs 1 may be provided, and the second electrode tab 2 is folded to form multiple folded segments arranged in a stacked manner, and one first electrode tab 1 is clamped between adjacent folded segments.

[0238] As an example, both the first electrode tab 1 and the second electrode tab 2 are folded to form multiple folded segments arranged in a stacked manner.

[0239] As an example, multiple separators 3 may be provided and are respectively arranged between any adjacent first electrode tab 1 or second electrode tab 2.

[0240] As an example, the separator 3 may be continuously provided and is arranged between any adjacent first electrode tab 1 or second electrode tab 2 by folding or winding.

[0241] In some embodiments, the shape of the electrode assembly 101 may be cylindrical, flat, prismatic, or the like.

[0242] Please refer to Figures 6 - 10 As shown, in some embodiments, a battery cell 100 is provided. The battery cell 100 includes a housing 200 and an electrode assembly 101. The housing 200 is provided with an electrode lead-out portion 2011; at least a part of the electrode assembly 101 is disposed inside the housing 200; the electrode assembly 101 includes a first electrode tab 1, and the first electrode tab 1 includes a current collector 10 and an active material layer 20. The current collector 10 includes an insulating substrate 11 and a metal layer 12. The insulating substrate 11, the metal layer 12, and the active material layer 20 are stacked along the thickness direction of the current collector 10, and at least a part of the metal layer 12 is located between the insulating substrate 11 and the active material layer 20; wherein, the metal layer 12 includes a conductive main body portion 13 and a conductive portion 14 extending from the conductive main body portion 13 in a first direction, the first direction is perpendicular to the thickness direction of the current collector 10, at least a part of the conductive main body portion 13 is covered with the active material layer 20, at least a part of the conductive portion 14 is not covered with the active material layer 20, and the conductive portion 14 is connected to the electrode lead-out portion 2011; along the thickness direction of the current collector 10, the thickness of the conductive portion 14 is greater than the thickness of the conductive main body portion 13.

[0243] A part of the electrode assembly 101 is located inside the housing 200; another part is located outside the housing 200, or the entire electrode assembly 101 is located inside the housing 200.

[0244] In some examples, the first electrode tab 1 is a positive electrode tab, the current collector 10 is a positive current collector, the positive current collector adopts a composite current collector structure, and the active material layer 20 is a positive active material layer; or, the first electrode tab 1 is a negative electrode tab, the current collector 10 adopts a negative current collector structure, the negative current collector adopts the above-mentioned composite current collector, and the active material layer 20 is a negative active material layer.

[0245] The current collector 10 includes a metal layer 12 and an insulating substrate 11. The current collector 10 is a multi-layer structure. The insulating substrate 11 may refer to a component made of an insulating material (for example: the above-mentioned polymer substrate) in the current collector 10, and the metal layer 12 may refer to a component made of the above-mentioned metal material in the current collector 10.

[0246] The surface of the insulating substrate 11 is covered with a metal layer 12, and the surface of the metal layer 12 facing away from the insulating substrate 11 is covered with an active material layer 20, so that the insulating substrate 11, the metal layer 12, and the active material layer 20 are stacked, and the stacking direction of the insulating substrate 11, the metal layer 12, and the active material layer 20 is the thickness direction of the current collector 10 (see Figure 7 the Y direction in). Among them, the active material layer 20 can be directly covered on the surface of the metal layer 12, or other substances can be covered on the surface of the metal layer 12 and then the active material layer 20 can be covered.

[0247] In some examples, one surface of the insulating substrate 11 is covered with a metal layer 12.

[0248] In some examples, both opposite surfaces of the insulating substrate 11 are covered with metal layers 12. Among the two metal layers 12, at least one metal layer 12 has an active material layer 20 covering the surface facing away from the insulating body.

[0249] The first direction may refer to a direction perpendicular to the thickness direction of the current collector 10; the second direction may refer to a direction perpendicular to the thickness direction and the first direction of the current collector 10.

[0250] In some examples, the electrode assembly 101 is a wound structure. When the first electrode tab 1 is in the unfolded state, the first direction can refer to the width direction of the first electrode tab 1 (see Figure 6 the Z direction in); the second direction can refer to the length direction of the first electrode tab 1 (see Figure 6 the X direction in). When the first electrode tab 1 is in the wound state, the second direction can also refer to the winding direction of the first electrode tab 1 (see Figure 4 the direction indicated by the arrow V in).

[0251] In some examples, the electrode assembly 101 has a laminated structure. The first direction can be the width direction of the first electrode sheet 1 (refer to the Z direction in Figure 6 ), and the second direction can refer to the length direction of the first electrode sheet 1 (refer to the X direction in Figure 6 ).

[0252] In some examples, along the first direction, the metal layer 12 is divided into two parts. One part is the conductive main body part 13, and the other part is the conductive part 14. The conductive part 14 is formed by the extension of the conductive main body part 13 along the first direction. A part of the area of the conductive main body part 13 is covered with the active material layer 20, and another part of the area of the conductive main body part 13 is not covered with the active material layer 20. Or, the entire area of the conductive main body part 13 is covered with the active material layer 20; a part of the area of the conductive part 14 is not covered with the active material layer 20, another part of the area of the conductive part 14 is covered with the active material layer 20, or the entire area of the conductive part 14 is not covered with the active material layer 20.

[0253] The electrode lead-out part 2011 can refer to a conductive component for outputting or inputting electric energy. The electrode lead-out part 2011 is connected to an external electronic device so that the battery cell 100 outputs or inputs electric energy; the electrode lead-out part 2011 can also be called a terminal post. The electrode lead-out part 2011 can be provided on the housing 202 or on the end cap 201.

[0254] The electrode lead-out part 2011 is connected to the conductive part 14. The electrode lead-out part 2011 can be directly connected to the conductive part 14; for example, the electrode lead-out part 2011 is directly welded to the conductive part 14; or, the electrode lead-out part 2011 can be connected to the conductive part 14 through a conductive component (such as the conductive member 30, etc.). For example, the first end of the conductive component is welded to the electrode lead-out part 2011, and the second end of the conductive component is welded to the conductive part 14; among them, the second end of the conductive component can be directly welded to the conductive part 14 or can be welded through a conductive piece (such as a connecting piece, etc.).

[0255] For the battery cell 100 according to the embodiment of the present application, when the battery cell 100 is in normal use, the electrode lead-out portion 2011 is used to input or output electric energy, realizing the charging and discharging of the battery cell 100; and the thickness of the conductive portion 14 connected to the electrode lead-out portion 2011 is greater than the thickness of the conductive main body portion 13, which increases the current-carrying area of the conductive portion 14, improves the current-carrying capacity of the conductive portion 14, reduces the heat generation of the battery cell 100, is beneficial to improving the charge-discharge efficiency of the battery cell 100, and improves the fast-charging performance of the battery cell 100; in addition, the current collector 10 adopts a composite structure of an insulating matrix 11 and a metal layer 12. Compared with the current collector 10 made of pure metal, the thickness of the metal layer 12 is small, and the burrs generated during the manufacturing process of the current collector 10 are small, reducing the risk of internal short circuit of the battery cell 100 and being beneficial to improving the use reliability of the battery cell 100; therefore, the battery cell 100 according to the embodiment of the present application can better balance the fast-charging performance and the use reliability.

[0256] In some embodiments, the surface of the conductive portion 14 facing away from the insulating matrix 11 is farther away from the insulating matrix 11 than the surface of the conductive main body portion 13 facing away from the insulating matrix 11.

[0257] In the direction of the insulating matrix 11 facing the metal layer 12, the surface of the conductive portion 14 facing away from the insulating matrix 11 protrudes relative to the surface of the conductive main body portion 13 facing away from the insulating matrix 11.

[0258] In some examples, in the direction of the metal layer 12 facing the insulating matrix 11, the surface of the conductive portion 14 facing the insulating matrix 11 may protrude from the surface of the conductive main body portion 13 facing the insulating matrix 11, and the insulating matrix 11 forms a notch at the conductive portion 14 to accommodate the conductive portion 14.

[0259] In some examples, the surface of the conductive portion 14 facing the insulating matrix 11 may be flush with the surface of the conductive main body portion 13 facing the insulating matrix 11. The insulating matrix 11 may adopt an equal-thickness structure, and the structural strength of the insulating matrix 11 is good, improving the structural strength of the current collector 10 and the use reliability of the battery cell 100.

[0260] By adopting the technical solution of this embodiment, the surface of the conductive portion 14 facing away from the insulating matrix 11 protrudes relative to the surface of the conductive main body portion 13 facing away from the insulating matrix 11, the side space of the conductive portion 14 facing away from the insulating matrix 11 can be utilized, the risk that the insulating matrix 11 is thinned at the conductive portion 14 to accommodate the conductive portion 14 can be reduced, the structural strength of the insulating matrix 11 at the conductive portion 14 can be improved, the structural strength of the current collector 10 can be improved, and the use reliability of the battery cell 100 can be improved.

[0261] In some embodiments, the conductive part 14 includes a first conductive part 141 and a second conductive part 142 arranged along a first direction. The first conductive part 141 is connected between the second conductive part 142 and the conductive main body part 13. The first conductive part 141 is covered with an active material layer 20, the second conductive part 142 is not covered with the active material layer 20, and the second conductive part 142 is connected to the electrode lead-out part 2011.

[0262] The first conductive part 141 may refer to the part of the conductive part 14 covered with the active material layer 20; the second conductive part 142 may refer to the part of the conductive part 14 not covered with the active material layer 20; the first conductive part 141 and the second conductive part 142 are separated by the end face of the active material layer 20; the thicknesses of both the first conductive part 141 and the second conductive part 142 are greater than the thickness of the conductive main body part 13.

[0263] Exemplarily, the conductive part 14 can be divided into two parts along the first direction. Among them, the part close to the conductive main body part 13 and covered with the active material layer 20 is the first conductive part 141, and the part far from the conductive main body part 13 and not covered with the active material layer 20 is the second metal layer 12.

[0264] The second conductive part 142 not covered with the active material layer 20 is connected to the electrode lead-out part 2011. On the one hand, it is convenient for the connection between the electrode lead-out part 2011 and the metal layer 12. On the other hand, it can reduce the risk of contact between the electrode lead-out part 2011 and the active material layer 20, reduce the mutual influence between the two, and is beneficial to improving the use reliability of the battery cell 100.

[0265] By adopting the technical solution of this embodiment, the active material layer 20 covers the first conductive part 141, which is beneficial to improving the electron transfer ability between the active material layer 20 and the first conductive part 141, reducing the resistance between the active material layer 20 and the first conductive part 141, and is beneficial to improving the fast charging performance of the battery cell 100; in addition, the conductive main body part 13 and the first conductive part 141 are also covered with the active material layer 20, which is beneficial to improving the electron transfer ability at the junction of the first conductive part 141 and the conductive main body part 13 of the first electrode sheet 1, beneficial to reducing the resistance of the first electrode sheet 1, and beneficial to improving the fast charging performance of the battery cell 100. In some embodiments, the active material layer 20 includes a first active material part 21 and a second active material part 22 arranged along the first direction. The first active material part 21 is connected to the second active material part 22. The thickness of the first active material part 21 is less than the thickness of the second active material part 22. At least part of the first active material part 21 covers the first conductive part 141, and at least part of the second active material part 22 covers the conductive main body part 13.

[0266] The second active material portion 22 may refer to the main body portion of the active material layer 20, and the second active material portion 22 may generally be an equal-thickness structure; the first active material portion 21 may refer to a portion with a thickness less than that of the second active material portion 22; exemplarily, the first active material portion 21 may be directly connected to the second active material portion 22, and the active material layer 20 is divided into two parts along the first direction, where the part close to the conductive portion 14 is the first active material portion 21, and the part far from the conductive portion 14 is the second active material portion 22.

[0267] The first active material portion 21 is located at the edge of the active material layer 20 to cover the first conductive portion 141. Among them, a part of the first active material portion 21 may cover the first conductive portion 141, another part of the first active material portion 21 and the entire second active material portion 22 both cover the conductive main body portion 13, or the entire first active material portion 21 covers the first conductive portion 141, and the entire second active material portion 22 covers the conductive main body portion 13, or the entire first active material portion 21 covers a part of the first conductive portion 141, a part of the second active material portion 22 covers another part of the first conductive portion 141, and another part of the second active material portion 22 covers the conductive main body portion 13.

[0268] In some examples, the first active material portion 21 may generally be an equal-thickness structure, and the thickness of the first active material portion 21 is less than that of the second active material portion 22, so that the first active material portion 21 and the second active material portion 22 form a stepped structure; in other examples, the thickness of the first active material portion 21 may also decrease step by step, so that the first active material portion 21 is a stepped structure; or, along the direction of the conductive main body portion 13 towards the conductive portion 14, the thickness of the first active material portion 21 may also decrease slowly, so that the thickness of the first active material portion 21 decreases slowly, and the outer shape of the first active material portion 21 is more rounded or smooth.

[0269] By adopting the technical solution of this embodiment, during the forming process of the first electrode sheet 1, the active material layer 20 can be roll-pressed to compact the active material layer 20; and the setting of the first active material portion 21 can reduce the roll pressure received by the edge of the active material layer 20 and reduce the risk of cracking at the edge of the active material layer 20. In addition, at least part of the first active material portion 21 covers the first conductive portion 141, and the thickness of the first conductive portion 141 is greater than that of the conductive main body portion 13, and the first active material portion 21 covers this part, which is beneficial to reducing the overall thickness of the first electrode sheet 1 at the first active material portion 21 and also beneficial to reducing the edge pressure of the active material layer 20, and further reducing the risk of cracking at the edge of the active material layer 20.

[0270] In some embodiments, the surface of the first active material portion 21 facing away from the insulating substrate 11 is closer to the insulating substrate 11 than the surface of the second active material portion 22 facing away from the insulating substrate 11.

[0271] It can be understood that along the direction of the insulating substrate 11 towards the metal layer 12, the conductive main body portion 13 protruding from the first active material portion 21 can make the thickness of the first electrode sheet 1 at the first active material portion 21 less than the thickness of the first electrode sheet 1 at the conductive main body portion 13.

[0272] By adopting the technical solution of this embodiment, the roll pressure received at the first active material portion 21 can be reduced, which is beneficial to the cracking risk of the active material layer 20.

[0273] In some embodiments, the second active material portion 22 covers a part of the first conductive portion 141, and the first active material portion 21 covers the other part of the first conductive portion 141.

[0274] A part of the first conductive portion 141 is covered by the second active material portion 22, and the other part is covered by the first active material portion 21.

[0275] By adopting the technical solution of this embodiment, the second active material portion 22 covers the first conductive portion 141, and there is more active material covering the first conductive portion 141. The electron transfer ability between the first conductive portion 141 and the active material layer 20 is better, which is beneficial to reducing the resistance between the active material layer 20 and the first conductive portion 141 and improving the fast charging ability of the battery cell 100.

[0276] In some embodiments, along the first direction, the size of the part of the first conductive portion 141 covered by the second active material portion 22 is W 1 , and the size of the part of the first conductive portion 141 covered by the first active material portion 21 is W 2 , W 1 ≥W 2 .

[0277] Along the first direction, the first conductive portion 141 is divided into two parts. The larger part is covered by the second active material portion 22, and the smaller part is covered by the first active material portion 21.

[0278] Exemplarily, the size W 1 of the part of the first conductive portion 141 covered by the second active material portion 22 may refer to the width of the part of the first conductive portion 141 covered by the second active material portion 22. The size W 2 of the part of the first conductive portion 141 covered by the first active material portion 21 may refer to the width of the part of the first conductive portion 141 covered by the first active material portion 21.

[0279] By adopting the technical solution of this embodiment, a larger part of the first conductive part 141 is covered by the second active material part 22, and a smaller part of the first conductive part 141 is covered by the first active material part 21, so that the first conductive part 141 is covered by more active materials, and the electron transfer ability between the first conductive part 141 and the active material layer 20 is better, which is conducive to reducing the resistance between the active material layer 20 and the first conductive part 141 and improving the fast charging ability of the battery cell 100.

[0280] In some embodiments, the thickness of the conductive main body part 13 is t 1 , and the maximum thickness of the first conductive part 141 is t 2 , and the thickness of the second active material part 22 is t 3 , where 0.002 ≤ (t 2 - t 1 ) / t 3 ≤ 0.08.

[0281] The second conductive part 142 is generally an equal-thickness structure, and the thickness of the second conductive part 142 is equal to the maximum thickness t of the first conductive part 141 2 , and the thickness of the second conductive part 142 can be the maximum thickness t of the conductive part 14 4 ; in some examples, the first conductive part 141 is generally an equal-thickness structure, and the maximum thickness of the first conductive part 141 is the thickness of the first conductive part 141; in another example, the first conductive part 141 can also be a multi-segment structure, where the thickness of each segment is inconsistent, and the maximum thickness of the first conductive part 141 is equal to the thickness of the thickest segment. For example, the first conductive part 141 includes two segments. Along the direction from the conductive main body part 13 to the conductive part 14, the thickness of the first segment gradually increases, and the second segment is generally an equal-thickness structure. The first segment is located between the second segment and the conductive main body part 13, and the thickness of the second segment is equal to the maximum thickness of the first conductive part 141; the first segment gradually increases from the thickness of the conductive main body part 13 to the thickness of the second segment. With such a setting, the first segment is smoothly connected to the second segment and the conductive main body part 13, which is conducive to reducing stress concentration and improving the structural strength.

[0282] t 2 - t 1 , may refer to the thickness difference between the first conductive part 141 and the conductive main body part 13.

[0283] (t 2 - t 1 ) / t 3 The value of can be 0.002, 0.08, and any value between 0.002 and 0.08; for example, (t 2 - t 1 ) / t 3The value of can be but is not limited to 0.002, 0.003, 0.004, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08.

[0284] In some examples, 0.002≤(t 2 -t 1 ) / t 3 The setting of ≤0.08 allows the thickness difference between the first conductive part 141 and the conductive main body 13 to be within the thickness error range of the active material layer 20. In this way, the thickening of the first conductive part 141 is not likely to cause the surface of the active material layer 20 to bulge out, thereby improving the flatness of the surface of the active material layer 20 facing away from the insulating substrate 11, which is beneficial to improving the manufacturability of the first pole piece 1, and can also reduce subsequent rolling damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, which is beneficial to improving the reliability of the battery cell 100.

[0285] By adopting the technical solution of this embodiment, the ratio of the thickness difference between the first conductive part 141 and the conductive main body part 13 to the thickness of the second active material part 22 is within a reasonable range, thereby improving the flatness of the surface of the active material layer 20 facing away from the insulating substrate 11, which is beneficial to improving the manufacturability of the first pole piece 1.

[0286] In some embodiments, 0.003≤(t 2 -t 1 ) / t 3 ≤0.06.

[0287] By adopting the technical solution of this embodiment, 0.003≤(t 2 -t 1 ) / t 3 ≤0.06, the ratio of the thickness difference between the first conductive portion 141 and the conductive main body portion 13 to the thickness of the second active material portion 22 is in a more reasonable range, thereby improving the flatness of the surface of the active material layer 20 facing away from the insulating substrate 11, which is beneficial to improving the manufacturability of the first pole piece 1.

[0288] In some embodiments, 60 μm ≤ t 3 ≤250μm.

[0289] Understandably, t 3 The value of can be 60 μm, 250 μm, and any value between 60 μm and 250 μm; for example, t 3 The value of can be, but is not limited to, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 250 μm.

[0290] t 3 With a design of ≥ 60 μm, the battery cell 100 can have a higher capacity; t 3 With a design of ≤ 250 μm, the distance for electrons to escape from the part of the active material layer 20 close to the metal layer 12 is not too long, which is beneficial to the escape of electrons and improves the capacity of the battery cell 100.

[0291] By adopting the technical solution of this embodiment, the thickness of the second active material part 22 is within a suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and service reliability of the battery cell 100, and can also reduce the risk of difficult ion escape in the area of the active material layer 20 close to the conductive layer, thus improving the performance of the battery cell 100.

[0292] In some embodiments, 80 μm ≤ t 3 ≤ 180 μm.

[0293] By adopting the technical solution of this embodiment, with the setting of 80 μm ≤ t 3 ≤ 180 μm, the thickness of the second active material part 22 is within a more suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and service reliability of the battery cell 100, and can also reduce the risk of difficult ion escape in the area of the active material layer 20 close to the conductive layer, thus improving the performance of the battery cell 100.

[0294] In some embodiments, along the first direction, the size of the first conductive part 141 is W 3 , and the size of the conductive part 14 is W 4 , where W 3 / W 4 ≤ 0.4.

[0295] Exemplarily, the size W 3 of the first conductive part 141 may refer to the width of the first conductive part 141, and W 3 = W 1 + W 2 ; the size W 4 of the conductive part 14 may refer to the width of the conductive part 14, where W 4 = W 3 + W 7 , where W 7 may refer to the size of the second conductive part 142 along the first direction, that is, the width of the second conductive part 142.

[0296] W 3 / W 4 ≤ 0.4, it can be understood that W 3 / W 4The value can be 0.4 and any value between 0 and 0.4; for example, W 3 / W 4 The value can be, but is not limited to, 0.001, 0.1, 0.2, 0.3, 0.4.

[0297] By adopting the technical solution of this embodiment, W 3 / W 4 ≤0.4 is designed such that along the first direction, the ratio of the size of the first conductive part 141 to the size of the conductive part 14 is reasonably set, facilitating the connection between the second conductive part 142 and the electrode lead-out part 2011. There is a good electron transport ability between the first conductive part 141 and the active material layer 20, which is beneficial to reducing the resistance of the first electrode sheet 1 and improving the fast charging performance of the battery cell 100.

[0298] In some embodiments, along the first direction, the size of the first conductive part 141 is W 3 , and the size of the conductive part 14 is W 4 , where 2 mm ≤ W 4 -W 3 ≤ 10 mm.

[0299] W 4 -W 3 , which may refer to the size of the second conductive part 142 along the first direction, that is, the width of the second conductive part 142, that is, W 7 .

[0300] 2 mm ≤ W 4 -W 3 ≤ 10 mm. It can be understood that the value of W 4 -W 3 can be 2 mm, 10 mm, and any value between 2 mm and 10 mm; for example, the value of W 4 -W 3 can be, but is not limited to, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm.

[0301] By adopting the technical solution of this embodiment, 2 mm ≤ W 4 -W 3 ≤ 10 mm is designed such that along the first direction, the size of the second conductive part 142 is within a reasonable range, facilitating the connection between the second conductive part 142 and the electrode lead-out part 2011, and can also reduce the excessive space occupied due to the too large size of the second conductive part 142 along the first direction, which is beneficial to improving the energy density of the battery cell 100.

[0302] In some embodiments, 3 mm ≤ W 4 -W 3 ≤ 6 mm.

[0303] By adopting the technical solution of this embodiment, 2 mm ≤ W 4 -W 3 ≤ 10 mm, the size of the second conductive part 142 in the first direction is within a more reasonable range, facilitating the connection between the second conductive part 142 and the electrode lead-out part 2011, and also reducing the excessive space occupied due to the over-large size of the second conductive part 142 in the first direction, which is beneficial to improving the energy density of the battery cell 100.

[0304] In some embodiments, in the first direction, the size of the first conductive part 141 is W 3 , and the size of the conductive main body part 13 is W 5 , where W 3 / (W 3 +W 5 ) ≤ 0.45.

[0305] Exemplarily, the size W 5 of the conductive main body part 13 may refer to the width of the conductive main body part 13. W 3 +W 5 may refer to the width of the part of the metal layer 12 covered with the active material layer 20.

[0306] W 3 / (W 3 +W 5 ) may refer to the ratio of the width of the part of the conductive part 14 covered with the active material layer 20 to the width of the part of the metal layer 12 covered with the active material layer 20.

[0307] W 3 / (W 3 +W 5 ) ≤ 0.45. It can be understood that the value of W 3 / (W 3 +W 5 ) can be 0.45 and any value between 0 and 0.45; exemplarily, the value of W 3 / (W 3 +W 5 ) can be but is not limited to 0.001, 0.1, 0.2, 0.3, 0.4, 0.45.

[0308] By adopting the technical solution of this embodiment, W 3 / (W 3 +W 5) The design with ≤0.45 makes the ratio of the size of the first conductive part 141 to the sum of the size of the first conductive part 141 and the size of the conductive main body part 13 within a suitable range along the first direction. The first conductive part 141 can cover the active material layer 20, which is beneficial to reducing the internal resistance of the first electrode sheet 1 and improving the fast charging ability of the battery cell 100. Additionally, along the second direction, the size of the first conductive part 141 is not too large, which is beneficial to reducing the occupied space and weight of the first conductive part 141 and improving the energy density of the battery cell 100.

[0309] In some embodiments, along the first direction, the size of the first conductive part 141 is W 3 , where 10mm ≤ W 3 ≤ 100mm.

[0310] It can be understood that the value of W 3 can be 10mm, 100mm, and any value between 10mm and 100mm; by way of example, the value of W 3 can be but is not limited to 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm.

[0311] By adopting the technical solution of this embodiment, the design of 10mm ≤ W 3 ≤ 100mm makes the size of the first conductive part 141 within a reasonable range along the first direction, enabling better electron transfer ability between the active material layer 20 and the first conductive part 141. Additionally, along the second direction, the size of the first conductive part 141 is not too large, which is beneficial to reducing the occupied space and weight of the first conductive part 141 and improving the energy density of the battery cell 100.

[0312] In some embodiments, the second conductive part 142 includes at least one protruding part 1421. The protruding part 1421 is connected to the first conductive part 141. Along the second direction, the size of the protruding part 1421 is smaller than the size of the conductive main body part 13. The second direction is perpendicular to the thickness direction and the first direction of the current collector 10.

[0313] The protruding part 1421 may refer to a protruding structure at the edge of the metal layer 12, and along the second direction, the size l 1 of the protruding part 1421 is smaller than the size L 1 of the conductive main body part 13. The number of the protruding parts 1421 can be one or more. The thickness of the protruding part 1421 is greater than the thickness of the conductive main body part 13; the number of the protruding parts 1421 can be one or more, and multiple protruding parts 1421 are arranged at intervals along the second direction.

[0314] In some examples, the protrusion 1421 directly extends outward from the end of the first conductive part 141 in the first direction. Alternatively, the second conductive part 142 further includes a portion connecting the first conductive part 141 and the protrusion 1421.

[0315] By adopting the technical solution of this embodiment, along the second direction, the dimension l of the protrusion 1421 1 is smaller than the dimension L of the conductive main body part 13 1 The protrusion 1421 is small, and it is easy for the protrusion 1421 to be bent with the conductive member 30 and connected to the electrode lead-out part 2011, which is convenient for processing and manufacturing, and is also beneficial to reducing the space occupied after the conductive member 30 is bent, and is beneficial to improving the energy density of the battery cell 100.

[0316] In some embodiments, the protrusion 1421 includes a first protruding sub-part 14211 and a second protruding sub-part 14212. The first protruding sub-part 14211 is connected between the second protruding sub-part 14212 and the first conductive part 141, and the first protruding sub-part 14211 is connected to the electrode lead-out part 2011; along the second direction, the dimension of the first protruding sub-part 14211 is larger than the dimension of the second protruding sub-part 14212.

[0317] The protrusion 1421 includes a first protruding sub-part 14211 and a second protruding sub-part 14212. The thickness of the first protruding sub-part 14211 and the thickness of the second protruding sub-part 14212 are both larger than the thickness of the conductive main body part 13.

[0318] Along the second direction, the dimension l of the first protruding sub-part 14211 2 is larger than the dimension l of the second protruding sub-part 14212 3 That is, the protrusion 1421 has a stepped structure. Along the second direction, the part with the larger dimension is the first protruding sub-part 14211, and the part with the smaller dimension is the second protruding sub-part 14212, and a plurality of protrusions 1421 are arranged at intervals along the second direction, so that the sum of the dimensions of the first protruding sub-parts 14211 of the plurality of protrusions 1421 is smaller than the dimension of the conductive main body part 13.

[0319] By adopting the technical solution of this embodiment, along the second direction, the first protruding sub-part 14211 is large, the current-carrying area of the first protruding sub-part 14211 is large, and the current-carrying capacity is strong, which is beneficial to reducing heat generation and improving the fast charging performance and use reliability of the battery cell 100.

[0320] In some examples, the electrode lead-out portion 2011 is connected to the first protruding sub-portion 14211, so that current can flow into or out of the electrode lead-out portion 2011 through the first protruding sub-portion 14211. In this way, the first protruding sub-portion 14211 can be directly used for overcurrent. The first protruding sub-portion 14211 has a strong overcurrent capacity, which is beneficial to reducing heat generation and improving the fast charging performance and use reliability of the battery cell 100.

[0321] In some examples, both the first protruding sub-portion 14211 and the second protruding sub-portion 14212 are connected to the electrode lead-out portion 2011, so that current can flow into or out of the electrode lead-out portion 2011 through the first protruding sub-portion 14211 and the second protruding sub-portion 14212. In this way, the first protruding sub-portion 14211 and the second protruding sub-portion 14212 can be directly used for overcurrent. The overcurrent area is large and the overcurrent capacity is good, which is beneficial to reducing heat generation and improving the fast charging performance and use reliability of the battery cell 100.

[0322] Of course, in other examples, it may also be that only the second protruding sub-portion 14212 is connected to the electrode lead-out portion 2011.

[0323] In some embodiments, the number of the protruding portions 1421 is multiple, and the multiple protruding portions 1421 are arranged at intervals along the second direction. Along the second direction, the sum of the sizes l of all the protruding portions 1421 1 is less than the size L of the conductive main body portion 13 1 .

[0324] The multiple protruding portions 1421 are arranged at intervals along the length direction of the first electrode tab 1. After the first electrode tab 1 is wound, the multiple protruding portions 1421 are stacked to form a whole and then bent and connected to the electrode lead-out portion 2011. In addition, the gap between two adjacent protruding portions 1421 also makes the sum of the sizes l of the multiple protruding portions 1421 along the second direction 1 less than the size L of the conductive main body portion 13 1 ; among them, the multiple protruding portions 1421 can adopt the same structure or different structures.

[0325] By adopting the technical solution of this embodiment, the multiple protruding portions 1421 are arranged at intervals along the second direction, which is beneficial to dividing the conductive main body portion 13 into multiple regions along the second direction, and one region can correspond to one protruding portion 1421. The electrons in each region can be transmitted to the electrode lead-out portion 2011 through the corresponding protruding portion 1421, so that the electrons of the conductive main body portion 13 are transmitted in sub-regions. The electron transmission path in each region to the corresponding protruding portion 1421 is short, which is beneficial to reducing the electron transmission distance, reducing the overall resistance of the first electrode tab 1, and improving the fast charging performance and use reliability of the battery cell 100.

[0326] In some embodiments, the second conductive portion 142 further includes a transition portion 1422. The transition portion 1422 is connected between the protruding portion 1421 and the first conductive portion 141. Along the second direction, the dimension L of the transition portion 1422 2 is greater than the sum of the dimensions l of all the protruding portions 1421 1 .

[0327] The transition portion 1422 may refer to the part of the metal layer 12 located between the protruding portion 1421 and the first conductive portion 141. The transition portion 1422 is continuously arranged along the second direction, such that along the second direction, the dimension L of the transition portion 1422 2 is greater than the sum of the dimensions l of all the protruding portions 1421 1 , or, along the second direction, the dimension L of the transition portion 1422 2 is equal to the dimension l of the protruding portion 1421 1 .

[0328] In some examples, the second conductive portion 142 includes a transition portion 1422 and a protruding portion 1421; the second conductive portion 142 may also include only the protruding portion 1421

[0329] By adopting the technical solution of this embodiment, the thickness of the transition portion 1422 is greater than the thickness of the conductive main body portion 13, and the dimension L of the transition portion 1422 along the second direction 2 is large, the current-carrying capacity of the transition portion 1422 is strong, which is beneficial to reducing heat generation and improving the fast charging performance and service reliability of the battery cell 100

[0330] In some embodiments, along the second direction, the dimension of the conductive main body portion 13 is L 1 , and the dimension of the transition portion 1422 is L 2 , 0.8 ≤ L 2 / L 1 ≤ 1

[0331] 0.8 ≤ L 2 / L 1 ≤ 1. Along the second direction, the dimension L of the transition portion 1422 2 is less than or equal to the dimension L of the conductive main body portion 13 1 , and the dimension L of the transition portion 1422 2 is greater than or equal to 0.8 times the dimension L of the conductive main body portion 13 1 . The dimension L of the transition portion 1422 2 exceeds more than half of the dimension L of the conductive main body portion 13 1 . The larger the dimension L of the transition portion 1422 2 , the better the current-carrying capacity of the transition portion 1422

[0332] In some examples, 0.8 ≤ L2 / L 1 <1, along the second direction, the transition part 1422 can be located at the middle position of the conductive main body part 13, and both ends of the transition part 1422 are not flush with the conductive main body part 13.

[0333] In some examples, 0.8 ≤ L 2 / L 1 <1, along the second direction, the transition part 1422 can also be disposed to be biased towards one end of the conductive main body part 13, such that one end of the transition part 1422 is flush with the conductive main body part 13 and the other end is not flush, or both ends are not flush. L 2 / L 1 The value of can be but is not limited to 0.8, 1 or any value between 0.8 and 1. Exemplarily, L 2 / L 1 The value of can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0334] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L 2 / L 1 ≤ 1 makes the size L of the transition part 1422 along the second direction 2 close to the size L of the conductive main body part 13 1 , the transition part 1422 has a larger size and better over-current carrying capacity, which is beneficial to reducing heat generation and improving the fast charging performance and service reliability of the battery cell 100.

[0335] In some embodiments, L 2 =L 1 .

[0336] L 2 / L 1 =1, along the second direction, the size L of the transition part 1422 2 is equal to the size L of the conductive main body part 13 1 , in the second direction, both ends of the transition part 1422 are flush with the conductive main body part 13 and form an equal-length structure.

[0337] By adopting the technical solution of this embodiment, the transition part 1422 and the conductive main body form an equal-length structure, the transition part 1422 has better over-current carrying capacity, which is more beneficial to reducing heat generation and improving the fast charging performance and service reliability of the battery cell 100.

[0338] In some embodiments, the first electrode tab 1 further includes a conductive member 30. The conductive member 30 includes a first connecting portion 31 and a second connecting portion 32 arranged in a first direction. The first connecting portion 31 is connected to the second connecting portion 32. The first connecting portion 31 is connected to the surface of the second conductive portion 142 facing away from the insulating substrate 11. The second connecting portion 32 is located on the side of the second conductive portion 142 facing away from the first conductive portion 141, and the second connecting portion 32 is connected to the electrode lead-out portion 2011.

[0339] The conductive member 30 may refer to a component connecting the electrode lead-out portion 2011. The conductive member 30 is made of a metal material, such as copper, aluminum, etc. When the first electrode tab 1 is a positive electrode tab, the conductive member 30 may be an aluminum foil. When the first electrode tab 1 is a negative electrode tab, the conductive member 30 may be a copper foil.

[0340] The conductive member 30 includes a first connecting portion 31 and a second connecting portion 32. The first connecting portion 31 may refer to the part where the conductive member 30 is connected to the second conductive portion 142, and the second connecting portion 32 may refer to the part where the conductive member 30 is connected to the electrode lead-out portion 2011.

[0341] In some examples, the first connecting portion 31 may cover and be connected to the second conductive portion 142. The second connecting portion 32 may extend from the side of the first connecting portion 31 facing away from the active material layer 20 in the first direction to protrude outside the insulating substrate 11, that is, along the thickness direction of the current collector 10. The projection of the first connecting portion 31 is located within the projection of the second conductive portion 142, and the projection of the second connecting portion 32 is located outside the projection range of the second conductive portion 142. In this way, the connection positions of the second conductive portion 142 and the electrode lead-out portion 2011 on the conductive member 30 are different, which is convenient for connection and can also reduce the mutual influence between the two connections, being beneficial to connection reliability. Of course, in other examples, along the thickness direction of the current collector 10, the projections of the first connecting portion 31 and the second connecting portion 32 may also partially overlap.

[0342] Exemplarily, the first connecting portion 31 may be directly welded to the surface of the second conductive portion 142 facing away from the insulating substrate 11. The welding connection operation is convenient and facilitates processing and manufacturing. Of course, connection can also be achieved by other means.

[0343] Exemplarily, the second connecting portion 32 and the electrode lead-out portion 2011 may be connected by direct welding, or may also be welded through a conductive member (such as a transfer piece, etc.). The welding method has convenient connection operation and facilitates processing and manufacturing. Of course, connection can also be achieved by other means.

[0344] In some cases, when the electrode sheet is wound to form the electrode assembly 101, the insulating matrix 11 is located between two adjacent layers of the second conductive portion 142, making it difficult for the two adjacent layers of the second conductive portion 142 to be directly connected across the insulating matrix 11 to transfer current outward. As a result, the current can almost only be transferred outward from the outermost layer of the second metal layer 12, resulting in poor conductivity, low fast charging performance and low reliability in use, and it is easy to cause local overheating, affecting the reliability in use of the battery cell 100. In the battery cell 100 according to the embodiment of the present application, the first connection portion 31 of the conductive member 30 is connected to the second conductive portion 142, and the second connection portion 32 of the conductive member 30 can protrude outside the insulating matrix 11. In this way, the two adjacent layers of the second conductive portion 142 can be electrically connected by using the second connection portion 32, thereby breaking the insulation limitation of the insulating matrix 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast charging performance and reliability in use of the battery cell 100, reducing heat generation, and improving the reliability in use of the battery cell 100.

[0345] When the electrode sheets are stacked to form the electrode assembly 101, the insulating matrix 11 is located between two adjacent metal layers 12, making it difficult for the two adjacent metal layers 12 to be directly connected across the insulating matrix 11 to transfer current outward. As a result, the current can almost only be transferred outward from the outermost metal layer 12, resulting in poor conductivity, low fast charging performance and low reliability in use, and it is easy to cause local overheating, affecting the reliability in use of the battery cell 100. In the battery cell 100 according to the embodiment of the present application, the first connection portion 31 of the conductive member 30 is connected to the second conductive portion 142, and the second connection portion 32 of the conductive member 30 can protrude outside the insulating matrix 11. In this way, the two adjacent second conductive portions 142 can be electrically connected by using the second connection portion 32, thereby breaking the insulation limitation of the insulating matrix 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast charging performance and reliability in use of the battery cell 100, reducing heat generation, and improving the reliability in use of the battery cell 100.

[0346] By adopting the technical solution of this embodiment, the second connection portion 32 protrudes outside the second conductive portion 142, which is convenient for the second connection portion 32 to be connected to the electrode lead-out portion 2011, and the processing and manufacturing are more convenient.

[0347] In some embodiments, along the first direction, the first connection portion 31 is arranged at an interval from the active material layer 20.

[0348] The first connection portion 31 is not in direct contact with the active material layer 20, but there is a certain gap therebetween, so that the first connection portion 31 does not contact the active material layer 20.

[0349] In some examples, the first electrode tab 1 is a positive electrode tab, and the first connection portion 31 does not contact the active material layer 20, which can reduce risks such as lithium plating, and is beneficial to improving the usage reliability of the battery cell 100. In other examples, the first electrode tab 1 is a negative electrode tab, and the first connection portion 31 may or may not contact the active material layer 20.

[0350] By adopting the technical solution of this embodiment, the first connection portion 31 does not contact the active material layer 20, which can reduce the mutual influence between the two and improve the usage reliability of the battery cell 100.

[0351] In some embodiments, the first connection portion 31 is welded to the surface of the second conductive portion 142 facing away from the insulating substrate 11 to form a first welding mark 51.

[0352] The first connection portion 31 covers the surface of the second conductive portion 142 facing away from the insulating substrate 11, and the first connection portion 31 and the second conductive portion 142 are connected by welding; the mark formed after the first connection portion 31 and the second conductive portion 142 are welded is the first welding mark 51.

[0353] The first connection portion 31 is welded to the second conductive portion 142, that is, the first connection portion 31 is welded to the area of the metal layer 12 where the active material layer 20 is not covered, 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 false soldering, and is beneficial to improving the connection reliability and current-carrying capacity between the metal layer 12 and the conductive member 30.

[0354] By adopting the technical solution of this embodiment, the first connection portion 31 is welded to the second conductive portion 142, and the conductive member 30 and the second conductive portion 142 are connected by welding, which is convenient for the production of the first electrode tab 1; in addition, the thickness of the second conductive portion 142 is small, and the surface of the second conductive portion 142 facing away from the insulating substrate 11 is large, which is beneficial to increasing the welding area between the first connection portion 31 and the second conductive portion 142, increasing the current-carrying area between the first connection portion 31 and the second conductive portion 142, being beneficial to improving the current-carrying capacity of the first electrode tab 1, improving the fast charging performance and usage reliability of the battery cell 100; at the same time, it can also reduce the risk of problems such as false soldering between the first connection portion 31 and the second conductive portion 142, being beneficial to improving the connection reliability between the second conductive portion 142 and the conductive member 30, and also being beneficial to improving the current-carrying capacity of the first electrode tab 1, improving the fast charging performance and usage reliability of the battery cell 100.

[0355] In some embodiments, the second conductive portion 142 includes at least one protruding portion 1421. The protruding portion 1421 is connected to the first conductive portion 141. Along the second direction, the size of the protruding portion 1421 is smaller than the size of the conductive main body portion 13. The second direction is perpendicular to the thickness direction and the first direction of the current collector 10. The first welding mark 51 includes a first welding mark portion 511. The first connecting portion 31 is welded to the surface of the protruding portion 1421 facing away from the insulating substrate 11 to form the first welding mark portion 511.

[0356] The first connecting portion 31 is stacked on the surface of the protruding portion 1421 facing away from the insulating substrate 11 and welded to the protruding portion 1421. The trace formed by the welding is the first welding mark portion 511.

[0357] In some examples, the first connecting portion 31 can be welded to the entire protruding portion 1421, or the first connecting portion 31 can be welded to a part of the protruding portion 1421, and the other part of the first protruding portion 1421 is not welded to the first connecting portion 31.

[0358] By adopting the technical solution of this embodiment, the first connecting portion 31 and the protruding portion 1421 are connected by welding. The connection method is simple and convenient for the production of the first electrode tab 1. In addition, the first connecting portion 31 and the protruding portion 1421 can directly use the first welding mark portion 511 for current conduction, which is beneficial to improving the current conduction ability between the first connecting portion 31 and the protruding portion 1421.

[0359] In some embodiments, along the second direction, the first welding mark portion 511 extends from one side edge of the protruding portion 1421 to the other side edge of the protruding portion 1421.

[0360] Along the first direction, the projection of the first welding mark portion 511 falls within the projection of the protruding portion 1421.

[0361] During the production process of the first electrode tab 1, the conductive member 30 can be welded to the edge of the equal-length current collector 10 by ultrasonic welding (for example: double-roll continuous ultrasonic welding) or other welding methods to form an equal-width welding mark, and then the conductive member 30 is cut by laser die-cutting or other cutting methods to form a tab to facilitate connection with the electrode lead-out portion 2011. During the cutting process, first cut along the second direction between the equal-width welding mark and the active material layer 20, then cut towards the equal-width welding mark until leaving the equal-width welding mark, continue to cut a certain distance away from the active material layer 20, then cut a certain distance along the second direction, and then cut towards the equal-width welding mark until leaving the equal-width welding mark, and then cut along the second direction, so as to obtain a first welding mark portion 511. By repeating this cycle, multiple first welding mark portions 511 can be obtained.

[0362] By adopting the technical solution of this embodiment, along the second direction, the size L of the first welding mark portion 5114 Large, which is beneficial to increasing the current-carrying area between the first connecting portion 31 and the protruding portion 1421, improving the current-carrying capacity between the first connecting portion 31 and the protruding portion 1421, reducing the risk of heat generation, and improving the fast charging performance and service reliability of the battery cell 100.

[0363] In some embodiments, the protruding portion 1421 includes a first protruding sub-portion 14211 and a second protruding sub-portion 14212. The first protruding sub-portion 14211 is connected between the second protruding sub-portion 14212 and the first conductive portion 141; along the second direction, the dimension l of the first protruding sub-portion 14211 2 is greater than the dimension l of the second protruding sub-portion 14212 3 ; the first welding mark portion 511 includes a first welding mark sub-portion 5111, and the first connecting portion 31 is welded to the first protruding sub-portion 14211 to form the first welding mark sub-portion 5111.

[0364] The first connecting portion 31 is welded to the surface of the first protruding sub-portion 14211 facing away from the insulating base 11, and the trace generated by the welding is the first welding mark sub-portion 5111.

[0365] By adopting the technical solution of this embodiment, the first connecting portion 31 is welded to the first protruding sub-portion 14211 to form the first welding mark sub-portion 5111. The dimension l of the first protruding sub-portion 14211 along the second direction 2 is large, which is beneficial to increasing the welding area between the protruding portion 1421 and the first connecting portion 31, increasing the current-carrying area between the protruding portion 1421 and the conductive portion, improving the current-carrying capacity, reducing heat generation, and being beneficial to improving the fast charging performance and service reliability of the battery cell 100; in addition, along the second direction, the dimension l of the second protruding sub-portion 14212 3 is small, which is beneficial to reducing the occupied space of the protruding portion 1421 and is beneficial to improving the energy density of the battery cell 100.

[0366] In some embodiments, along the second direction, the first welding mark sub-portion 5111 extends from one side edge of the first protruding sub-portion 14211 to the other side edge of the first protruding sub-portion 14211.

[0367] Along the first direction, the projection of the first welding mark sub-portion 5111 falls within the projection of the first protruding sub-portion 14211.

[0368] By adopting the technical solution of this embodiment, along the second direction, the dimension of the first welding mark sub-portion 5111 is large, which is beneficial to increasing the welding area between the protruding portion 1421 and the first connecting portion 31, increasing the current-carrying area between the protruding portion 1421 and the first connecting portion 31, improving the current-carrying capacity, reducing heat generation, and being beneficial to improving the fast charging performance and service reliability of the battery cell 100.

[0369] In some embodiments, the protrusion 1421 includes a first protrusion sub - part 14211 and a second protrusion sub - part 14212. The first protrusion sub - part 14211 is connected between the second protrusion sub - part 14212 and the first conductive part 141. Along the second direction, the size of the first protrusion sub - part 14211 is larger than that of the second protrusion sub - part 14212. The first welding mark part 511 includes a second welding mark sub - part 5112. The first connecting part 31 is welded to the surface of the second protrusion sub - part 14212 facing away from the insulating substrate 11 to form the second welding mark sub - part 5112.

[0370] Exemplarily, the surface of the second protrusion sub - part 14212 facing away from the insulating substrate 11 is welded to the first connecting part 31, and the trace generated by the welding is the second welding mark sub - part 5112.

[0371] By adopting the technical solution of this embodiment, there is a gap between the second welding mark sub - part 5112 and the active material layer 20, which can reduce problems such as false soldering, improve the welding reliability, and is beneficial to improving the use reliability of the battery cell 100.

[0372] In some embodiments, the protrusion 1421 includes a first protrusion sub - part 14211 and a second protrusion sub - part 14212. The first protrusion sub - part 14211 is connected between the second protrusion sub - part 14212 and the first conductive part 141. Along the second direction, the size of the first protrusion sub - part 14211 is larger than that of the second protrusion sub - part 14212. The first welding mark part 511 includes a first welding mark sub - part 5111. The first connecting part 31 is welded to the first protrusion sub - part 14211 to form the first welding mark sub - part 5111. The first welding mark part 511 further includes a second welding mark sub - part 5112. The first connecting part 31 is welded to the surface of the second protrusion sub - part 14212 facing away from the insulating substrate 11 to form the second welding mark sub - part 5112.

[0373] By adopting the technical solution of this embodiment, both the first protrusion sub - part 14211 and the second protrusion sub - part 14212 are welded to the first connecting part 31, which is beneficial to increasing the current - carrying area between the first connecting part 31 and the protrusion 1421, and is beneficial to improving the current - carrying capacity between the first connecting part 31 and the protrusion 1421.

[0374] In some embodiments, along the second direction, the second welding mark sub - part 5112 extends from one side edge of the second protrusion sub - part 14212 to the other side edge of the second protrusion sub - part 14212.

[0375] Along the first direction, the projection of the second welding mark sub - part 5112 falls within the projection of the second protrusion sub - part 14212.

[0376] By adopting the technical solution of this embodiment, the size of the second welding mark sub - part 5112 in the second direction is large, which is beneficial to increasing the welding area between the first connecting part 31 and the protruding part 1421, increasing the current - carrying area between the first connecting part 31 and the protruding part 1421, and is beneficial to improving the current - carrying capacity between the first connecting part 31 and the protruding part 1421.

[0377] In some embodiments, the number of the protruding parts 1421 is multiple, and the multiple protruding parts 1421 are arranged at intervals in the second direction; the first connecting part 31 includes multiple first connecting sub - parts 311, the multiple first connecting sub - parts 311 are arranged at intervals in the second direction, the number of the second connecting parts 32 is multiple, and each first connecting sub - part 311 is connected to each second connecting part 32 in one - to - one correspondence; each first connecting sub - part 311 is welded to the surface of each protruding part 1421 facing away from the insulating substrate 11.

[0378] The first connecting sub - part 311 may refer to the part of the first connecting part 31 covering the protruding part 1421; the number of the first connecting sub - parts 311, the number of the second connecting parts 32, and the number of the protruding parts 1421 are the same. One first connecting sub - part 311 corresponds to one protruding part 1421, one first connecting sub - part 311 is connected to one second connecting part 32 in one - to - one correspondence, and one first connecting sub - part 311 and one protruding part 1421 are welded to form one first welding mark part 511.

[0379] By adopting the technical solution of this embodiment, the multiple first connecting sub - parts 311 of the first connecting part 31 are arranged at intervals in the second direction, and there is a gap between two adjacent first connecting sub - parts 311, which can reduce the material required for the first connecting part 31 and reduce the manufacturing cost of the battery cell 100.

[0380] Please refer to Figures 11 - 21 As shown, in some embodiments, the second conductive part 142 includes a transition part 1422 and at least one protruding part 1421. The transition part 1422 is connected between the first conductive part 141 and the protruding part 1421. In the second direction, the size of the transition part 1422 is greater than the sum of the sizes of all the protruding parts 1421; the second direction is perpendicular to the thickness direction and the first direction of the current collector 10; the first welding mark 51 further includes a second welding mark part 512, and the first connecting part 31 is welded to the surface of the transition part 1422 facing away from the insulating substrate 11 to form the second welding mark part 512.

[0381] The first connecting part 31 is welded to the surface of the transition part 1422 facing away from the insulating substrate 11, and the trace generated by the welding of the transition part 1422 and the first connecting part 31 is the second welding mark part 512.

[0382] In some examples, the first weld mark 51 includes a second weld mark portion 512 and a first weld mark portion 511. That is, the first connection portion 31 simultaneously welds the transition portion 1422 and the protruding portion 1421. The first weld mark portion 511 is located between the second weld mark portion 512 and the active material layer 20.

[0383] In some examples, the first weld mark 51 only includes the second weld mark portion 512. That is, the first connection portion 31 only welds with the transition portion 1422. At this time, the first connection portion 31 and the second conductive portion 142 only conduct current through the current-carrying portion. In this way, it is not necessary to use the protruding portion 1421 to conduct current, and the heat generation risk at the junction of the protruding portion 1421 and the current-carrying portion is also reduced, which is beneficial to improving the fast charging performance of the battery cell 100.

[0384] By adopting the technical solution of this embodiment, the first connection portion 31 and the transition portion 1422 are connected by welding. The connection method is simple, which is beneficial to facilitating the production of the first electrode plate 1. In addition, along the second direction, the size of the transition portion 1422 is large, and the current-carrying capacity of the transition portion 1422 is good. The first connection portion 31 and the first conductive portion 141 can directly use the transition portion 1422 to conduct current. In this way, the current-carrying pressure between the protruding portion 1421 and the current-carrying portion can be reduced, and even the protruding portion 1421 is not required to conduct current, reducing the heat generation risk, which is beneficial to improving the fast charging performance of the battery cell 100.

[0385] In some embodiments, the first weld mark 51 can be only the first weld mark portion 511. That is, the first connection portion 31 welds with the protruding portion 1421 and does not weld with the transition portion 1422.

[0386] In some embodiments, the first weld mark 51 can be only the second weld mark portion 512. That is, the first connection portion 31 welds with the transition portion 1422 and does not weld with the protruding portion 1421.

[0387] In some embodiments, along the second direction, the size of the transition portion 1422 is L 2 , and the size of the second weld mark portion 512 is L 3 , 0.8 ≤ L 3 / L 2 ≤ 1.

[0388] 0.8 ≤ L 3 / L 2 ≤ 1. Along the second direction, the size L of the second weld mark portion 512 3 can be less than or equal to the size L of the transition portion 1422 2 , the size L of the second weld mark portion 512 3 is greater than 0.8 times the size L of the transition portion 1422 2 , and the size L of the second weld mark portion 512 3 exceeds the size L of the transition portion 14222 more than half of, the dimension L of the second welding mark portion 512 3 The longer it is, the larger the welding area between the transition portion 1422 and the first connecting portion 31, and the better the current-carrying capacity at the connection between the transition portion 1422 and the first connecting portion 31.

[0389] In some examples, 0.8 ≤ L 3 / L 2 <1. Along the second direction, the second welding mark portion 512 can be located at the middle position of the transition portion 1422, and both ends of the second welding mark portion 512 are not flush with the transition portion 1422.

[0390] In some examples, 0.8 ≤ L 2 / L 1 <1. Along the second direction, the second welding mark portion 512 can also be disposed to be biased towards one end of the transition portion 1422, such that one end of the transition portion 1422 is flush with the transition portion 1422, the other end is not flush, or both ends are not flush.

[0391] L 3 / L 2 The value of can be but is not limited to 0.8, 1, or any value between 0.8 and 1. Exemplarily, L 3 / L 2 The value of can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0392] By adopting the technical solution of this embodiment, the design of 0.8 ≤ L 3 / L 2 ≤1 makes the dimension of the second welding mark portion 512 larger along the second direction, which is beneficial to increasing the welding area between the first connecting portion 31 and the transition portion 1422, improving the current-carrying capacity at the connection between the first connecting portion 31 and the transition portion 1422, improving the current-carrying capacity of the first pole piece 1, reducing heat generation, and improving the fast charging performance and use reliability of the battery cell 100.

[0393] In some embodiments, L 3 =L 2 .

[0394] L 3 / L 2 =1. Along the second direction, the dimension L of the second welding mark portion 512 3 is equal to the dimension L of the transition portion 1422 2 , and both ends of the second welding mark portion 512 are flush with the transition portion 1422 along the second direction.

[0395] In some examples, the protrusion 1421 and the transition portion 1422 are simultaneously welded to the first connecting portion 31 to form the entire welding mark. The first connecting portion 31 is welded to the transition portion 1422, which can effectively increase the welding area between the first connecting portion 31 and the metal layer 12, improve the current-carrying area between the first connecting portion 31 and the metal layer 12, and is beneficial to improving the current-carrying capacity between the first connecting portion 31 and the metal layer 12.

[0396] By adopting the technical solution of this embodiment, the design of L 3 / L 2 =1 makes the size of the second welding mark portion 512 in the second direction relatively large, which is beneficial to designing a relatively large welding area between the first connecting portion 31 and the transition portion 1422. The current-carrying capacity at the connection between the first connecting portion 31 and the transition portion 1422 is the best, which can effectively improve the current-carrying capacity of the first pole piece 1, reduce heat generation, and improve the fast charging performance and service reliability of the battery cell 100.

[0397] In some embodiments, the number of protrusions 1421 is multiple, and the multiple protrusions 1421 are arranged at intervals in the second direction; 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 arranged at intervals in the second direction, and each first connecting sub-portion 311 correspondingly covers each protrusion 1421; the number of second connecting portions 32 is multiple, and along the first direction, one side of each first connecting sub-portion 311 is correspondingly connected to each second connecting portion 32, and the other side of each first connecting sub-portion 311 is connected to the second connecting sub-portion 312, and the second connecting sub-portion 312 is continuously arranged in the second direction; the second connecting sub-portion 312 is welded to the surface of the transition portion 1422 facing away from the insulating substrate 11.

[0398] The second connecting sub-portion 312 may refer to the portion of the first connecting portion 31 covering the transition portion 1422; the second connecting sub-portion 312 is continuously arranged in the second direction. For example, along the second direction, the second connecting sub-portion 312 extends from one side edge of the transition portion 1422 to the other side of the transition portion 1422.

[0399] The second connecting sub-portion 312 is welded to the surface of the transition portion 1422 facing away from the insulating substrate 11 to form the second welding mark portion 512.

[0400] In some examples, during the process of cutting the conductive member 30, first cut along the second direction on the equal-width welding mark, and then cut along the direction away from the active material layer 20 until leaving the equal-width welding mark. After that, continue to cut along the direction away from the active material layer 20 for a certain distance, then continue to cut along the second direction for a certain distance, and then cut along the direction towards the active material layer 20 until cutting a certain distance of the equal-width welding mark. Then, continue to cut along the second direction on the equal-width welding mark, and so on in a cyclic manner, and the first welding mark 51 can be obtained. Among them, taking the cutting position along the second direction on the equal-width welding mark as a reference, along the first direction, the part of the first welding mark 51 located on the side of the cutting position towards the active material layer 20 is the second welding mark part 512, and the part located on the side of the cutting position away from the active material layer 20 is the first welding mark part 511. The first welding mark part 511 can be a convex structure of the second welding mark part 512 away from the active material layer 20. After the cutting is completed, during the cutting process from the direction away from the active material layer 20 to the direction towards the active material layer 20, a convex part 1421 is cut out from the metal layer 12 of the current collector 10, and a second connection part 32 and a first connection sub-part 311 are cut out from the conductive member 30. During the cutting process along the second direction, a transition part 1422 is formed between the convex part 1421 and the active material layer 20, and a second connection sub-part 312 is cut out from the conductive member 30.

[0401] By adopting the technical solution of this embodiment, the second connection sub-parts 312 are continuously arranged along the second direction, and multiple first connection sub-parts 311 can be connected into a whole. The second connection sub-parts 312 can play a good supporting role for the first connection sub-parts 311, can reduce the risk of the first connection sub-parts 311 being bent when inserted between the first pole piece 1 and the second pole piece 2, reduce the risk of short circuit, and are beneficial to improving the use reliability of the battery cell 100. In addition, along the second direction, the size of the second connection sub-parts 312 is large, which is beneficial to increasing the welding area between the second connection sub-parts 312 and the transition part 1422, beneficial to improving the current-carrying capacity at the connection between the first connection part 31 and the transition part 1422, improving the current-carrying capacity of the first pole piece 1, and improving the fast charging performance and use reliability of the battery cell 100.

[0402] In some embodiments, along the second direction, the size L of the first welding mark part 511 4 is smaller than the size L of the second welding mark part 512 3 .

[0403] By adopting the technical solution of this embodiment, along the second direction, the size L of the second welding mark part 512 3 is large, the welding area between the transition part 1422 and the first connection part 31 is large, which is beneficial to improving the current-carrying capacity of the first connection part 31 and the transition part 1422, and beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0404] In some embodiments, the number of the protruding portions 1421 is plural, the plural protruding portions 1421 are arranged at intervals along the second direction, and each protruding portion 1421 is welded to the first connecting portion 31 to form a first welding mark portion 511.

[0405] The number of the protruding portions 1421 is plural, for example: two, three, four, etc.; the plural protruding portions 1421 are arranged at intervals along the second direction.

[0406] In some examples, after the first pole piece 1 is wound or stacked, the plural protruding portions 1421 are stacked together, and at the same time, the plural second connecting portions 32 are also stacked together, thereby breaking the insulation limitation of the insulating matrix 11, effectively improving the conductivity of the first pole piece 1, improving the fast charging performance of the single battery device 1100, reducing the heat generation of the single battery device 1100, and improving the use reliability of the metal layer 12 of the single battery device 1100.

[0407] The plural protruding portions 1421 are arranged at intervals along the second direction, so that along the second direction, the sum of the sizes l of all the protruding portions 1421 1 is less than the size L of the transition portion 1422 2 , the sum of the sizes L of all the first welding mark portions 511 4 is less than the size L of the second welding mark portion 512 3 , and the size L of the second welding mark portion 512 3 is large, which is beneficial to increasing the welding area between the transition portion 1422 and the first connecting portion 31, beneficial to increasing the current-carrying capacity at the connection between the transition portion 1422 and the conductive member 30, beneficial to increasing the current-carrying capacity of the first pole piece 1, reducing heat generation, and improving the fast charging performance and use reliability of the single battery 100.

[0408] Among the plural first welding mark portions 511, along the second direction, the sizes L of some of the first welding mark portions 511 4 may be the same, or the sizes L of all the first welding mark portions 511 4 may be completely different, or the sizes L of all the first welding mark portions 511 4 may be the same.

[0409] In some examples, the second welding mark portion 512 and the first welding mark portion 511 are directly connected.

[0410] The second welding mark portion 512 and the first welding mark portion 511 form an integral first welding mark 51, and there is no obvious dividing line therebetween; the integral first welding mark 51 can cover the junction of the protruding portion 1421 and the transition portion 1422; in the actual manufacturing process, the second welding mark portion 512 and the first welding mark portion 511 are formed by cutting the equal-width welding mark as described above.

[0411] In some examples, the second welding imprint portion 512 and the first welding imprint portion 511 adopt the structure of welding points, and the pitch of the welding points in the second welding imprint portion 512 is the same as that in the first welding imprint portion 511; exemplarily, the welding points in the second welding imprint portion 512 and the first welding imprint portion 511 are not welded to the junction line between the protruding portion 1421 and the transition portion 1422, and the distance between two adjacent welding points in the second welding imprint portion 512 and the first welding imprint portion 511 is equal to the pitch of the welding points in the second welding imprint portion 512; exemplarily, the welding points are welded to the junction line between the protruding portion 1421 and the transition portion 1422, thereby connecting the second welding imprint portion 512 and the first welding imprint portion 511 into a whole welding imprint.

[0412] By adopting the technical solution of this embodiment, the first welding imprint 51 can cover the junction between the protruding portion 1421 and the transition portion 1422, and a part of the current can directly flow through the transition portion 1422 to the first connection portion 31, reducing the overcurrent pressure at the junction between the protruding portion 1421 and the transition portion 1422, which is beneficial to improving the overcurrent capacity of the first electrode sheet 1, reducing heat generation, and is beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0413] In some embodiments, the electrode assembly 101 further includes an insulating member 40. The insulating member 40 includes a first insulating portion 41, and the first insulating portion 41 covers the surface of the second conductive portion 142 facing away from the insulating substrate 11, and the entire first insulating portion 41 is located between the first welding imprint 51 and the active material layer 20.

[0414] The insulating member 40 may refer to a component capable of insulating. The insulating member 40 includes a first insulating portion 41, and the first insulating portion 41 may refer to an insulating component covering the surface of the metal layer 12 facing away from the active material layer 20; the first insulating portion 41 may be, but is not limited to, an insulating coating, insulating glue (such as: hot melt glue) or insulating tape.

[0415] Along the thickness direction of the current collector 10, the first insulating portion 41 does not coincide with the first welding imprint 51, and the first insulating portion 41 is arranged at an interval from the first welding imprint 51, so that the first connection portion 31 will not be welded to the first insulating portion 41, which is beneficial to reducing the risk of false soldering between the first connection portion 31 and the metal layer 12; or, the first insulating portion 41 coincides with the first welding imprint 51 only at the edge, and the edge of the first welding imprint 51 coincides with the edge of the first insulating portion 41, resulting in a small risk of false soldering and good welding reliability between the first connection portion 31 and the metal layer 12.

[0416] By adopting the technical solution of this embodiment, the first insulating portion 41 can insulate the surface of the second conductive portion 142 facing away from the insulating substrate 11 from other components, which is beneficial to improving the use reliability of the battery cell 100; it is also beneficial to improving the connection reliability between the first connection portion 31 and the metal layer 12, and is also beneficial to improving the overcurrent capacity.

[0417] In some embodiments, the first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0418] In some examples, the entire first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0419] In some examples, when the first connecting portion 31 is only welded to the protruding portion 1421 and the first connecting portion 31 is spaced from the transition portion 1422, a part of the first insulating portion 41 covers the first protruding sub-portion 14211, and another part covers the transition portion 1422. Of course, in other examples, the first insulating portion 41 may only cover the transition portion 1422.

[0420] In some examples, when both the protruding portion 1421 and the transition portion 1422 are welded to the first connecting portion 31, the first insulating portion 41 covers the transition portion 1422.

[0421] By adopting the technical solution of this embodiment, the first insulating portion 41 can support the portion of the second conductive portion 142 located between the first connecting portion 31 and the active material layer 20, and can reduce damages 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 ability of this portion and the fast charging performance and service reliability of the battery cell 100; in addition, the first insulating portion 41 can also insulate this portion, reduce the short-circuit risk of the battery cell 100, and improve the service reliability of the battery cell 100.

[0422] In some embodiments, the insulating member 40 further includes a second insulating portion 42, and at least a part of the second insulating portion 42 covers the first solder mark 51.

[0423] The second insulating portion 42 may refer to an insulating component covering the first solder mark 51. The first insulating portion 41 and the second insulating portion 42 may be an integrally formed structure or two separate components connected together.

[0424] The second insulating portion 42 may be, but is not limited to, an insulating coating, an insulating adhesive (such as: hot melt adhesive) or an insulating tape.

[0425] A part of the first insulating portion 41 may cover the first solder mark 51, another part covers the first insulating portion 41 or the active material layer 20, or the entire first insulating portion 41 covers the first solder mark 51.

[0426] By adopting the technical solution of this embodiment, components such as tip protrusions and metal debris will be generated on the surface of the first welding mark 51. The second insulating portion 42 covers the surface of the first welding mark 51, which can prevent the tip protrusions and metal debris from contacting the second pole piece 2, reduce the short-circuit risk of the battery cell 100, and improve the use reliability of the battery cell 100.

[0427] In some embodiments, along the first direction, one side of the second insulating portion 42 covers the first welding mark 51, and the other side of the second insulating portion 42 covers at least a part of the first insulating portion 41.

[0428] It can be understood that one side of the second insulating portion 42 covers the first welding mark 51, and the other side of the second insulating portion 42 can cover the entire first insulating portion 41, or can cover a part of the first insulating portion 41, or even completely cover the active material layer 20.

[0429] In some examples, in addition to covering the first welding mark 51 and at least a part of the first insulating portion 41, the second insulating portion 42 can also cover the part of the first connecting portion 31 located between the first insulating portion 41 and the first welding mark 51. The coverage of the insulating member 40 is more comprehensive, which is more conducive to reducing the short-circuit risk and improving the use reliability of the battery cell 100.

[0430] By adopting the technical solution of this embodiment, the second insulating portion 42 and the first insulating portion 41 jointly cover the second conductive portion 142, which can achieve double-layer insulation, is conducive to reducing the short-circuit risk of the battery cell 100, and is conducive to improving the use reliability of the battery cell 100.

[0431] In some embodiments, the electrode assembly 101 further includes an insulating member 40. The insulating member 40 includes a second insulating portion 42, and at least a part of the second insulating portion 42 covers the first welding mark 51.

[0432] It can be understood that the insulating member 40 includes the second insulating portion 42. The insulating member 40 may not include the first insulating portion 41, or the insulating member 40 may include the first insulating portion 41 and the second insulating portion 42.

[0433] By adopting the technical solution of this embodiment, components such as tip protrusions and metal debris will be generated on the surface of the first welding mark 51. The second insulating portion 42 covers the surface of the first welding mark 51, which can prevent the tip protrusions and metal debris from contacting the second pole piece 2, reduce the short-circuit risk of the battery cell 100, and improve the use reliability of the battery cell 100.

[0434] In some embodiments, one side of the second insulating portion 42 covers the first welding mark 51, and the other side of the second insulating portion 42 covers at least a part of the active material layer 20.

[0435] One side of the second insulating portion 42 covers the first weld mark 51, and the other side of the second insulating portion 42 can directly cover a portion of the active material layer 20, or can cover the entire active material layer 20; for example, the second insulating portion 42 can cover the end of the first active material portion 21 facing away from the second active material portion 22, so that the first active material portion 21 can be used to provide an installation space for the second insulating portion 42, thereby reducing the risk of the surface of the first active material portion 21 facing away from the insulating substrate 11 protruding from the surface of the second active material portion 22 facing away from the insulating substrate 11; of course, the second insulating portion 42 can completely cover the first active material portion 21 and a portion of the second active material portion 22, or can cover the entire active material layer 20.

[0436] In some examples, the second conductive portion 142 is covered with the first insulating portion 41 . After the second insulating portion 42 completely covers the first insulating portion 41 , it may further extend onto the active material layer 20 to cover the active material layer 20 .

[0437] In some examples, the second conductive portion 142 is not covered by the first insulating portion 41. The second insulating portion 42 extends from the first weld mark 51 to the active material layer 20, so that the second conductive portion 142 can be covered between the conductive component 30 and the active material layer 20, thereby reducing the risk of short circuit in this part, which is beneficial to improving the reliability of the battery cell 100. In addition, the first insulating portion 41 can be omitted to save costs. At the same time, the active material layer 20 can be used to cover the original position of the first insulating portion 41, which can increase the fast charging performance and reliability of the active material layer 20, which is beneficial to improving the energy density of the battery cell 100.

[0438] By adopting the technical solution of this embodiment, the second insulating portion 42 extends from the first weld mark 51 to the active material layer 20 , and the second insulating portion 42 has a wide coverage area and a good insulation effect.

[0439] In some embodiments, along the first direction, a size of a portion of the insulating member 40 covering the active material layer 20 is H, wherein 0.2 mm≤H≤1.0 mm, and optionally, 0.3 mm≤H≤0.8 mm.

[0440] In some examples, the value of H may be 0.2 mm, 1 mm, or any value between 0.2 mm and 1.0 mm. For example, the value of H may be, but is not limited to, 0.2 mm, 0.3 mm, 0.4 mm, 0.6 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0441] The design with H≥0.2 mm enables the insulating member 40 to cover the end of the active material layer 20 facing the conductive portion 14. The insulating member 40 can block the burrs at the end of the active material layer 20 facing the conductive portion 14, improving the reliability of use of the battery cell 100. The design with H≤1.0 mm makes the portion of the insulating member 40 covering the active material layer 20 not too large, which is beneficial to reducing the weight and volume of the insulating member 40 and improving the energy density of the battery cell 100.

[0442] In some examples, the insulating member 40 includes a first insulating portion 41. The first insulating portion 41 covers the end of the active material layer 20 facing the conductive portion 14. The portion of the first insulating portion 41 covering the active material layer 20 may refer to the mutually soluble region formed by the first insulating portion 41 and the active material layer 20, so that the fixation of the first insulating portion 41 is more stable.

[0443] In some examples, the insulating member 40 includes a second insulating portion 42. The second insulating portion 42 covers the end of the active material layer 20 facing the extension portion.

[0444] By adopting the technical solution of this embodiment, along the first direction, the size of the portion of the insulating member 40 covering the active material layer 20 is reasonable, and it can take into account both blocking the burrs at the end of the active material layer 20 close to the conductive portion 14 and the energy density of the battery cell 100.

[0445] In some embodiments, 0.3 mm≤H≤0.8 mm.

[0446] By adopting the technical solution of this embodiment, along the first direction, the size of the portion of the second insulating portion 42 covering the active material layer 20 is more reasonable, and it can better take into account the problems of blocking the burrs at the end of the active material layer 20 close to the conductive portion 14 and the energy density of the battery cell 100.

[0447] In some embodiments, the number of the metal layers 12 is two. The two metal layers 12 are provided on opposite sides of the insulating substrate 11 along the thickness direction of the current collector 10. The number of the active material layers 20 is two. The two active material layers 20 respectively cover the two metal layers 12. The number of the conductive members 30 is two. The first connection portions 31 of the two conductive members 30 are respectively welded to the second conductive portions 142 of the two metal layers 12 to form two first weld marks 51. The number of the insulating members 40 is two. The second insulating portions 42 of the two insulating members 40 respectively cover at least part of the two first weld marks 51.

[0448] The number of the metal layers 12, the number of the insulating members 40, and the number of the conductive members 30 are all two. The two metal layers 12 respectively cover opposite sides of the insulating substrate 11 in the thickness direction. The two active material layers 20 respectively cover the first conductive portions 141 and the conductive main bodies 13 of the two metal layers 12. The first connection portion 31 of one conductive member 30 is welded to the surface of the second conductive portion 142 of one metal layer 12 facing away from the insulating substrate 11 to form a first welding mark 51. The first connection portion 31 of the other conductive member 30 is welded to the second conductive portion 142 of the other metal layer 12 to also form a first welding mark 51. The second insulating portions 42 of the two insulating members 40 cover the two first welding marks 51.

[0449] By adopting the technical solution of this embodiment, the first connection portions 31 of the two conductive members 30 are respectively welded to the metal layers 12 located on opposite sides of the insulating substrate 11, and the second connection portions 32 of the two conductive members 30 are located on the side of the second conductive portion 142 facing away from the first conductive portion 141. In this way, the two conductive portions 14 can be directly connected by using the second connection portions 32 of the two conductive members 30, thereby breaking the insulation limit 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 heat generation, and improving the use reliability of the battery cell 100, the metal layer 12.

[0450] In some embodiments, the first portion 421 covers the first welding mark 51. Along the direction from the conductive main body 13 to the conductive portion 14, the second portion 422 protrudes from the side surface of the second conductive portion 142. The second portion 422 is located on the side of the second connection portion 32 along the second direction, where the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0451] In some examples, the insulating member 40 has an equal-width structure. The insulating member 40 covers the conductive member 30 and the conductive portion 14 along the length direction of the first electrode sheet 1. Along the thickness direction of the current collector 10, the portion of the second insulating portion 42 within the projection range of the conductive portion 14 and the conductive member 30 is the first portion 421, and the portion of the second insulating portion 42 outside the projection range of the conductive portion 14 and the conductive member 30 and located on the side of the conductive portion 14 facing away from the conductive main body 13 is the second portion 422.

[0452] By adopting the technical solution of this embodiment, along the direction from the conductive main body 13 to the conductive portion 14, components such as metal debris at the side surface of the second conductive portion 142 away from the active material layer 20 can be located between the second portions 422 of the two insulating members 40. In this way, the risk of metal debris falling into the electrode assembly 101 can be reduced, which is beneficial to reducing the short-circuit risk.

[0453] In some embodiments, the second portions 422 of the two insulating members 40 are in contact with each other.

[0454] In some examples, the second parts 422 of the two insulating members 40 are located in the hollow area where the protruding part 1421 is not extended at the transition part 1422, and the second parts 422 of the two insulating members 40 can be close to each other and then fit together.

[0455] The second parts 422 of the two insulating members 40 can be pasted or statically adsorbed together, and of course, other fitting methods can also be used.

[0456] By adopting the technical solution of this embodiment, after the second parts 422 of the two insulating members 40 are fitted together, components such as metal debris on the side of the second conductive part 142 can be wrapped, so that components such as metal debris are not easily dropped into the electrode assembly 101, and the short - circuit risk of the battery cell 100 can be better reduced.

[0457] In some embodiments, along the direction of the conductive main body part 13 towards the conductive part 14, the second connecting parts 32 of the two conductive members 30 are welded to form a second weld mark 52.

[0458] The second connecting parts 32 of the two conductive members 30 can be welded by ultrasonic welding, laser welding and other methods.

[0459] By adopting the technical solution of this embodiment, after the second connecting parts 32 of the two conductive members 30 are welded, the second conductive parts 142 on the opposite sides of the insulating matrix 11 can be connected, thereby breaking the insulation limit of the insulating matrix 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast - charging performance of the battery cell 100, reducing heat generation, and improving the use reliability of the battery cell 100 and the metal layer 12.

[0460] In some embodiments, the second insulating part 42 covers the second weld mark 52. Along the direction from the conductive main body part 13 to the conductive part 14, the second insulating part 42 protrudes from the edge of the second weld mark 52 facing away from the conductive main body part 13.

[0461] Along the thickness direction of the current collector 10, the projection of the second weld mark 52 falls within the projection of the second insulating part 42, so that the second insulating part 42 can completely cover the second weld mark 52.

[0462] By adopting the technical solution of this embodiment, the second insulating part 42 can completely cover the second weld mark 52, preventing burrs, metal debris and other components on the second weld mark 52 from piercing through the separator 3 and connecting with the second electrode sheet 2, reducing the short - circuit risk, and improving the use reliability of the battery cell 100.

[0463] In some embodiments, the electrode assembly 101 includes a second electrode tab 2 having a polarity opposite to that of the first electrode tab 1. The second electrode tab 2 includes a main functional portion 210 and an ear portion 220. The ear portion 220 protrudes from the main functional portion 210 in a first direction. Along the direction from the conductive main body portion 13 to the conductive portion 14, the main functional portion 210 protrudes from the end face of the insulating member 40 facing the active material layer 20, and the main functional portion 210 does not protrude from the end face of the insulating member 40 away from the active material layer 20.

[0464] The second electrode tab 2 may refer to an electrode tab having a polarity opposite to that of the first electrode tab 1. Among them, the first electrode tab 1 is a positive electrode tab, and the second electrode tab 2 is a negative electrode tab, or the first electrode tab 1 is a negative electrode tab, and the second electrode tab 2 is a positive electrode tab. The first electrode tab 1 and the second electrode tab 2 can be wound after being stacked to form a wound electrode assembly 101; a plurality of first electrode tabs 1 and a plurality of second electrode tabs 2 are stacked to form a stacked electrode assembly 101.

[0465] The second electrode tab 2 includes a main functional portion 210 and an ear portion 220. The main functional portion 210 may refer to the main body portion of the second electrode tab 2, and the ear portion 220 may refer to the portion of the second electrode tab 2 protruding from the main functional portion 210. When the second electrode tab 2 is a negative electrode tab, the ear portion 220 may refer to a protruding structure located at the edge of the negative current collector 10 mentioned above, and the main functional portion 210 may include the portion of the negative current collector 10 other than the protruding structure and the negative active material layer 20. When the second electrode tab 2 is a positive electrode tab, the ear portion 220 may refer to a protruding structure located at the edge of the positive current collector 10 mentioned above, and the main functional portion 210 may include the portion of the positive current collector 10 other than the protruding structure and the positive active material layer 20.

[0466] During the manufacturing process of the second electrode tab 2, the edge of the second electrode tab 2 is die-cut to obtain the ear portion 220 and the main functional portion 210. During the die-cutting process, burrs are likely to be generated on the end face of the main functional portion 210 facing the ear portion 220.

[0467] Exemplarily, along the thickness direction of the current collector 10, the projection of the end face of the main functional portion 210 close to the ear portion 220 falls within the projection of the first insulating portion 41 or the projection of the second insulating portion 42.

[0468] By adopting the technical solution of this embodiment, the insulating member 40 can prevent the burrs at the end face of the main functional portion 210 of the second electrode tab 2 close to the ear portion 220 from piercing through the separator 3 and connecting to the first electrode tab 1, reducing the short-circuit risk between the first electrode tab 1 and the second electrode tab 2, and being beneficial to improving the use reliability of the battery cell 100.

[0469] In some embodiments, the second insulating portion 42 is connected to the first electrode tab 1.

[0470] The second insulating part 42 can be connected to the metal layer 12, the conductive member 30, or the active material layer 20. Among them, the second insulating part 42 can be connected to the first pole piece 1 by means of adhesion or pasting.

[0471] By adopting the technical solution of this embodiment, the second insulating part 42 is connected to the first pole piece 1, and the second insulating part 42 can be fixed, so as to stably block components such as burrs and metal chips, which is beneficial to reducing the short-circuit risk of the battery cell 100 and improving the use reliability of the battery cell 100.

[0472] Please refer to Figure 22 and Figure 23 As shown, in some embodiments, the second insulating part 42 includes an insulating base layer 423 and an adhesive layer 424, and the adhesive layer 424 is bonded between the insulating base layer 423 and the first pole piece 1.

[0473] The second insulating part 42 adopts the structural form of a tape; the insulating base layer 423 can refer to the main body part of the second insulating part 42, and the adhesive layer 424 can refer to the adhesive covering the surface of the insulating base layer 423. The material of the insulating base layer 423 includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and their block copolymers. The material of the adhesive layer 424 includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0474] By adopting the technical solution of this embodiment, the second insulating part 42 adopts the structural form of a tape, and the tape is easy to cover comprehensively, which is beneficial to reducing the risk of missed coverage and the internal short-circuit risk of the battery cell 100; the insulating base layer 423 can improve the structural strength of the second insulating part 42 and reduce the deformation during the fitting process of the second insulating part 42, which is beneficial to improving the insulation effect; the adhesive layer 424 can stably fix the insulating base layer 423 on the first pole piece 1 and reduce the risk of the insulating tape falling off.

[0475] In some embodiments, the layer thickness range of the insulating base layer 423 is 6μm to 15μm.

[0476] The layer thickness of the insulating base layer 423 is T 1 , 6μm ≤ T 1 ≤ 15μm. It can be understood that the value of T 1 can be 6μm, 15μm, and any value between 6μm and 15μm. For example, the value of T 1 can be but not limited to 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm.

[0477] T 1The design with a thickness of ≥6μm enables the insulating base layer 423 to have a certain thickness to block burrs and achieve insulation; T 1 The design with a thickness of ≤15μm ensures that the thickness of the insulating base layer 423 is not too large, which is beneficial to reducing the volume occupied by the second insulating part 42 and improving the energy density of the battery cell 100.

[0478] By adopting the technical solution of this embodiment, the internal insulation and energy density of the battery cell 100 can be taken into account simultaneously.

[0479] In some embodiments, the layer thickness range of the adhesive layer 424 is 0.5μm to 3μm.

[0480] The layer thickness of the adhesive layer 424 is T 2 , 0.5μm ≤ T 2 ≤ 3μm. It can be understood that the value of T 2 can be 0.3μm, 3μm, and any value between 0.3μm and 3μm. Exemplarily, the value of T 2 can be but is not limited to 0.3μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm.

[0481] T 2 The design with a thickness of ≥0.5μm enables the adhesive layer 424 to have a certain thickness, so that the second insulating part 42 can be stably bonded to the first pole piece 1, and the insulation reliability of the second insulating part 42 is good; T 2 The design with a thickness of ≤3μm ensures that the thickness of the adhesive layer 424 is not too large, which is beneficial to reducing the volume occupied by the second insulating part 42 and improving the energy density of the battery cell 100.

[0482] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell 100 can be taken into account simultaneously.

[0483] In some embodiments, the layer thickness range of the insulating base layer 423 is 6μm to 15μm; the layer thickness range of the adhesive layer 424 is 0.5μm to 3μm.

[0484] By adopting the technical solution of this embodiment, the insulation reliability and energy density of the battery cell 100 can be taken into account simultaneously.

[0485] In some embodiments, along the first direction, the size of the insulating part 40 is S, where 3mm ≤ S ≤ 9mm.

[0486] In some examples, the insulating part 40 includes the second insulating part 42, and S is equal to the size of the second insulating part 42 along the first direction.

[0487] In some examples, the insulating member 40 includes a second insulating portion 42 and a first insulating portion 41, and S is equal to the overall dimension of the second insulating portion 42 and the insulating coating in the first direction.

[0488] 3mm ≤ S ≤ 9mm. It can be understood that the value of S can be 3mm, 9mm, and any value between 3mm and 9mm. By way of example, the value of S can be, but is not limited to, 3mm, 4mm, 4.5mm, 5mm, 6mm, 6.5mm, 7mm, 8mm, 9mm.

[0489] The design with S ≥ 3mm enables the insulating member 40 to have a certain dimension in the first direction, which is beneficial to the internal insulation of the battery cell 100; the design with S ≤ 9mm ensures that the dimension S of the insulating member 40 in the first direction is not too large, which is beneficial to reducing the occupied volume of the insulating member 40 and improving the energy density of the battery cell 100.

[0490] 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 account simultaneously.

[0491] In some embodiments, 4.5mm ≤ S ≤ 6.5mm.

[0492] By adopting the technical solution of this embodiment, the dimension S of the insulating member 40 in the first direction is relatively reasonable, and both the insulation reliability and the energy density of the battery cell 100 can be better taken into account.

[0493] In some embodiments, the electrode assembly 101 includes a second electrode tab 2 with a polarity opposite to that of the first electrode tab 1. The second electrode tab 2 includes a main functional portion 210 and an electrode ear portion 220. The electrode ear portion 220 protrudes from the main functional portion 210 in the first direction; in the direction from the conductive main portion 13 to the conductive portion 14, the main functional portion 210 protrudes from the end face of the conductive portion 14 facing away from the conductive main portion 13.

[0494] In some examples, in the thickness direction of the current collector 10, the projection of the end face of the main functional portion 210 facing the electrode ear portion 220 does not coincide with the projection of the metal layer 12, and the burr at the end face of the main functional portion 210 of the second electrode tab 2 facing the electrode ear portion 220 corresponds to the hollowed-out area where the metal layer 12 does not extend beyond the second connection portion 32.

[0495] In some examples, in the thickness direction of the current collector 10, the projection of the first welding mark 51 can fall within the projection of the main functional portion 210, and the first welding mark 51 can be covered with the second insulating portion 42, so that the second insulating portion 42 can prevent burrs, metal debris and other components on the first welding mark 51 from piercing through the separator 3 and connecting to the second electrode tab 2, reducing the risk of short circuit and improving the service reliability of the battery cell 100.

[0496] By adopting the technical solution of this embodiment, the burrs at the end face of the main functional part 210 of the second pole piece 2 facing the pole ear part 220 correspond to the hollow area where the metal layer 12 does not extend out of the second connection part 32, which can also reduce the short - circuit risk of the battery cell 100 and improve the use reliability of the battery cell 100.

[0497] In some embodiments, along the first direction, the distance between the first welding mark 51 and the active material layer 20 is S 1 , where, 0.5mm ≤ S 1 ≤ 5mm.

[0498] S 1 ≥ 0.3mm design enables a distance between the first welding mark 51 and the active material layer 20, so that the conductive member 30 will not be welded to the active material layer 20, reducing the risk of problems such as false soldering; S 1 ≤ 5mm design enables the distance between the first welding mark 51 and the active material layer 20 not to be too large, which is beneficial to increasing the coverage area of the active material layer 20 on the metal layer 12 and beneficial to improving the energy density of the battery cell 100.

[0499] S 1 The value of S 1 can be 0.3mm, 5mm and any value between 0.3mm and 5mm. Exemplarily, the value of S

[0500] By adopting the technical solution of this embodiment, 0.3mm ≤ S 1 ≤ 5mm design enables the first welding mark 51 not to be welded to the active material layer 20, reducing problems such as false soldering, which is beneficial to improving the connection reliability between the first connection part 31 and the metal layer 12. In addition, since the distance between the active material layer 20 and the first welding mark 51 is small, the active material layer 20 can be relatively close to the first welding mark 51. Then, when the size of the metal layer 12 in the first direction is fixed, the area that the active material layer 20 can cover is larger, which is beneficial to improving the energy density of the battery cell 100.

[0501] In some embodiments, 0.5mm ≤ S 1 ≤ 2.8mm.

[0502] By adopting the technical solution of this embodiment, 0.5mm ≤ S 1 ≤ 2.8mm design makes the distance between the active material layer 20 and the first welding mark 51 more reasonable, which can better balance the connection reliability of the conductive member 30 and the energy density of the battery cell 100.

[0503] In some embodiments, along the first direction, the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20 are spaced apart.

[0504] In some examples, the first electrode tab 1 is a positive electrode tab, and there is a gap between the first welding mark 51 and the active material layer 20. This gap can be used to provide a spaced-apart space between the conductive member 30 and the active material layer 20 to reduce the risk of lithium plating caused by the contact between the conductive member 30 and the active material layer 20. Additionally, it can also provide a spaced-apart space between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, such that the first welding mark 51 does not extend to the position where the first connecting portion 31 faces the active material layer 20, reducing the risk of the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, etc. This is beneficial for reducing the burrs generated during welding and for improving the reliability of use of the battery cell 100.

[0505] In some examples, the first electrode tab 1 is a negative electrode tab, and there is a gap between the first welding mark 51 and the active material layer 20. This can provide a spaced-apart space between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, such that the second welding mark 52 does not extend to the position where the first connecting portion 31 faces the active material layer 20, reducing the risk of the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, etc. This is beneficial for reducing the burrs generated during welding and for improving the reliability of use of the battery cell 100; wherein, the conductive member 30 may or may not be in contact with the active material layer 20.

[0506] There is a gap between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, such that the first welding mark 51 does not extend to the position where the first connecting portion 31 faces the active material layer 20, reducing the risk of the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, etc. This is beneficial for reducing the burrs generated during welding and for improving the reliability of use of the battery cell 100.

[0507] In some embodiments, along the first direction, the distance between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20 is S 2 , where 0.3 mm ≤ S 2 ≤ 1.2 mm.

[0508] S 2 ≥ 1.2 mm design enables there to be a distance between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20, such that the first welding mark 51 does not extend to the position where the first connecting portion 31 faces the active material layer 20, reducing the risk of the end face of the first connecting portion 31 facing the active material layer 20 being welded through or cracked; S 2The design with a dimension ≤ 1.2 mm ensures that the distance between the first welding mark 51 and the end face of the first connecting portion 31 facing the active material layer 20 is not too large, which is beneficial to increasing the coverage area of the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell 100.

[0509] S 2 The value of S can be 0.3 mm, 1.2 mm, and any value between 0.3 mm and 1.2 mm. By way of example, the value of S 2 can be, but is not limited to, 0.3 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm.

[0510] By adopting the technical solution of this embodiment, the use reliability and energy density of the battery cell 100 can be better balanced.

[0511] In some embodiments, along the first direction, the dimension of the conductive portion 14 is W 4 , and the dimension of the conductive main body portion 13 is W 5 , where 0.01 ≤ W 4 / W 5 ≤ 0.8.

[0512] The dimension W of the conductive main body portion 13 5 may refer to the width of the conductive main body portion 13.

[0513] 0.01 ≤ W 4 / W 5 ≤ 0.8. It can be understood that the value of W 4 / W 5 can be 0.01, 0.8, and any value between 0.01 and 0.8; by way of example, the value of W 4 / W 5 can be, but is not limited to, 0.01, 0.02, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8.

[0514] By adopting the technical solution of this embodiment, the design of 0.01 ≤ W 4 / W 5 ≤ 0.8 makes the ratio of the dimension of the conductive portion 14 to the dimension of the conductive main body portion 13 along the first direction reasonably set, which can improve the over-current capacity at the conductive portion 14, enhance the fast charging performance and use reliability of the battery cell 100. In addition, along the first direction, the dimension of the conductive portion 14 is not too large, which is beneficial to reducing the occupied space and weight of the conductive portion 14 and improving the energy density of the battery cell 100.

[0515] In some embodiments, 0.05 ≤ W 4 / W 5 ≤ 0.6.

[0516] By adopting the technical solution of this embodiment, 0.05 ≤ W 4 / W 5 ≤ 0.6, the ratio of the size of the conductive part 14 to the size of the conductive main body part 13 is set more reasonably along the first direction, which can improve the over-current capacity at the conductive part 14, improve the fast charging performance and service reliability of the battery cell 100. In addition, along the first direction, the size of the conductive part 14 is not too large, which is beneficial to reducing the occupied space and weight of the conductive part 14, and is beneficial to improving the energy density of the battery cell 100.

[0517] In some embodiments, the thickness of the conductive main body part 13 is t 1 , and the maximum thickness of the conductive part 14 is t 4 , where 0.2 μm ≤ t 4 -t 1 ≤ 4.5 μm.

[0518] Exemplarily, the maximum thickness t 4 of the conductive part 14 may be equal to the thickness of the second conductive part 142.

[0519] t 4 -t 1 , which may refer to the thickness difference between the conductive part 14 and the conductive main body part 13 to characterize the thickening degree of the conductive part 14.

[0520] 0.2 μm ≤ t 4 -t 1 ≤ 4.5 μm. It can be understood that the value of t 4 -t 1 can be any value between 0.2 μm, 4.5 μm and 0.2 μm - 4.5 μm; Exemplarily, the value of t 4 -t 1 can be but not limited to 0.2 μm, 0.3 μm, 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 1.75 μm, 2 μm, 3 μm, 4 μm, 4.5 μm.

[0521] By adopting the technical solution of this embodiment, 0.2 μm ≤ t 4 -t 1 ≤ 4.5 μm, the difference between the maximum thickness of the conductive part 14 and the thickness of the conductive main body part 13 is within a reasonable range, which can improve the over-current capacity at the conductive part 14, improve the fast charging performance and service reliability of the battery cell 100. In addition, the thickness of the conductive part 14 is not too large, which is beneficial to reducing the occupied space and weight of the conductive part 14, and is beneficial to improving the energy density of the battery cell 100.

[0522] In some embodiments, 0.3 μm ≤ t4 -t 1 ≤1.75μm.

[0523] By adopting the technical solution of this embodiment, 0.3μm≤t 4 -t 1 The design of ≤1.75μm, the difference between the maximum thickness of the conductive part 14 and the thickness of the conductive main body 13 is within a more reasonable range, which can improve the current carrying capacity at the conductive part 14, improve the fast charging performance and reliability of the battery cell 100. In addition, the thickness of the conductive part 14 is not too large, which is beneficial to reducing the space and weight occupied by the conductive part 14, and is beneficial to improving the energy density of the battery cell 100.

[0524] In some embodiments, the thickness of the conductive body portion 13 is t 1 , the maximum thickness of the conductive portion 14 is t 4 , where 1<t 1 / t 4 ≤4, optionally, 1.5<t 1 / t 4 ≤2.5.

[0525] t 1 / t 4 , may refer to the ratio of the thickness of the conductive portion 14 to the thickness of the conductive body portion 13 , or may represent the degree of thickening of the conductive portion 14 .

[0526] 1<t 1 / t 4 ≤4, it is understandable that t 1 / t 4 The value of can be 4 or any value between 1 and 4; for example, t 1 / t 4 The value of can be but is not limited to 1.1, 1.5, 2, 2.5, 3, 3.5, 4.

[0527] By adopting the technical solution of this embodiment, 1<t 1 / t 4 ≤4, the ratio of the maximum thickness of the conductive part 14 to the thickness of the conductive main body 13 is within a reasonable range, which can improve the current carrying capacity at the conductive part 14, improve the fast charging performance and reliability of the battery cell 100. In addition, the thickness of the conductive part 14 is not too large, which is beneficial to reducing the occupied space and weight of the conductive part 14, and is beneficial to improving the energy density of the battery cell 100.

[0528] In some embodiments, 1.5 < t 1 / t 4 ≤2.5.

[0529] By adopting the technical solution of this embodiment, 1.5<t1 / t 4 ≤2.5, the ratio of the maximum thickness of the conductive part 14 to the thickness of the conductive main body 13 is within a more reasonable range, which can improve the current carrying capacity at the conductive part 14, improve the fast charging performance and reliability of the battery cell 100. In addition, the thickness of the conductive part 14 is not too large, which is beneficial to reducing the occupied space and weight of the conductive part 14, and is beneficial to improving the energy density of the battery cell 100.

[0530] In some embodiments, the thickness of the conductive portion 14 is t 4 , where 1μm≤t 4 ≤5μm.

[0531] 1μm≤t 4 ≤5μm, it is understandable that t 4 The value of can be 1 μm, 5 μm, and any value between 1 μm and 5 μm; for example, t 4 The value of can be, but is not limited to, 1 μm, 1.1 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, and 5 μm.

[0532] By adopting the technical solution of this embodiment, 1μm≤t 4 The thickness of the conductive part 14 is designed to be ≤5μm, and is reasonably designed to improve the current carrying capacity of the conductive part 14, and improve the fast charging performance and reliability of the battery cell 100. In addition, the thickness of the conductive part 14 is not too large, which is beneficial to reducing the occupied space and weight of the conductive part 14, and is beneficial to improving the energy density of the battery cell 100.

[0533] In some embodiments, 1.2 μm ≤ t 4 ≤3.5μm.

[0534] By adopting the technical solution of this embodiment, 1.2μm≤t 4 The design of ≤3.5μm, the thickness design of the conductive part 14 is more reasonable, which can improve the current carrying capacity at the conductive part 14, improve the fast charging performance and reliability of the battery cell 100. In addition, the thickness of the conductive part 14 is not too large, which is beneficial to reduce the occupied space and weight of the conductive part 14, and is beneficial to improve the energy density of the battery cell 100.

[0535] In some embodiments, the conductive portion 14 includes a first main segment 143 and a first transition segment 144, the first transition segment 144 is connected between the first main segment 143 and the conductive main portion 13, the thickness of the first transition segment 144 is greater than the thickness of the conductive main portion 13; the thickness of the first main segment 143 is greater than the thickness of the first transition segment 144; at least a portion of the first transition segment 144 is covered with an active material layer 20.

[0536] The first main body section 143 can be the main body part of the conductive part 14. The first main body section 143 is generally an equal-thickness structure. The first transition section 144 can be the part where the conductive part 14 is connected between the first main body section 143 and the conductive main body part 13. Exemplarily, the first main body section 143 can include the second conductive part 142 and the second section as described above, and the first transition section 144 can be the first section as described above.

[0537] The first transition section 144 can be partially covered with the active material layer 20 or can be entirely covered with the active material layer 20.

[0538] By adopting the technical solution of this embodiment, the setting of the first transition section 144 can reduce the stress concentration of the metal layer 12, can reduce the risk of cracks appearing during the forming process of the metal layer 12, can improve the current-carrying capacity of the conductive part 14, improve the fast charging performance and service reliability of the battery cell 100, and is also convenient for processing and manufacturing.

[0539] In some embodiments, along the direction from the conductive main body part 13 to the conductive part 14, the thickness of the first transition section 144 is set to increase.

[0540] Along the direction from the conductive main body part 13 to the conductive part 14, the thickness of the first transition section 144 can increase in a stepped manner or can increase slowly.

[0541] By adopting the technical solution of this embodiment, the stress concentration of the metal layer 12 can be better reduced, the risk of cracks appearing during the forming process of the metal layer 12 can be better reduced, the current-carrying capacity of the conductive part 14 can be improved, the fast charging performance and service reliability of the battery cell 100 can be improved, and it is also convenient for processing and manufacturing.

[0542] In some embodiments, along the first direction, the size of the first transition section 144 is W 6 , where 4 mm ≤ W 6 ≤ 50 mm. Optionally, 5 mm ≤ W 6 ≤ 34 mm.

[0543] The size W 6 of the first transition section 144 can refer to the width of the first transition section 144.

[0544] 4 mm ≤ W 6 ≤ 50 mm. It can be understood that the value of W 6 can be any value between 4 mm, 50 μm and 4 mm - 50 μm. Exemplarily, the value of W 6 can be but is not limited to 4 mm, 5 mm, 8 mm, 10 mm, 20 mm, 25 mm, 30 mm, 33 mm, 34 mm, 37 mm, 40 mm, 45 mm, 50 mm.

[0545] By adopting the technical solution of this embodiment, 4mm≤W 6 The design of the first transition section 144 is ≤50mm, and the size of the first transition section 144 along the first direction is reasonably designed, which can reduce the stress concentration of the metal layer 12, reduce the risk of cracks in the metal layer 12 during the molding process, improve the current carrying capacity of the conductive part 14, improve the fast charging performance and reliability of the battery cell 100, and facilitate processing and manufacturing. In addition, the size of the first transition section 144 along the first direction is not too large, which reduces the space and weight occupied by the conductive part 14, which is beneficial to improving the energy density of the battery cell 100.

[0546] In some embodiments, 5 mm ≤ W 6 ≤34mm.

[0547] By adopting the technical solution of this embodiment, 5mm≤W 6 The design of ≤34mm, the size design of the first transition section 144 along the first direction is more reasonable, which can reduce the stress concentration of the metal layer 12, reduce the risk of cracks in the metal layer 12 during the molding process, improve the current carrying capacity of the conductive part 14, improve the fast charging performance and reliability of the battery cell 100, and facilitate processing and manufacturing. In addition, the size of the first transition section 144 along the first direction is not too large, which reduces the space and weight occupied by the conductive part 14, which is beneficial to improve the energy density of the battery cell 100.

[0548] In some embodiments, the first pole piece 1 further includes a conductive protection layer 60 , and at least a portion of the conductive protection layer 60 is located between the active material layer 20 and the metal layer 12 .

[0549] The conductive protection layer 60 may refer to a conductive structure disposed between the active material layer 20 and the metal layer 12 . The conductive structure is conductive so that the battery cell 100 can output or input electrical energy.

[0550] A portion of the conductive protective layer 60 is located between the active material layer 20 and the metal layer 12, and another portion covers the metal layer 12 and protrudes out of the active material layer 20; for example, a portion of the conductive protective layer 60 covers the conductive main body 13 and the first conductive part 141, and another portion of the conductive protective layer 60 covers a partial area of ​​the second conductive part 142 close to the first conductive part 141.

[0551] For example, the conductive protective layer 60 may contain conductive carbon black and a binder, which, on the one hand, can play a buffering and lubricating role between the active material and the metal layer, and can alleviate the damage of the particles in the active material layer 20 to the metal layer 12 during the rolling process of the first pole piece 1; on the other hand, the conductive carbon black can reduce the contact resistance between the particles and the metal layer 12, which is beneficial to improving the performance of the battery cell 100.

[0552] During the rolling process of the first electrode tab 1, the thickness of the metal layer 12 is relatively thin, and the particles in the active material layer 20 may damage the metal layer 12, resulting in problems such as cracks in the metal layer 12. The conductive protective layer 60 in the embodiment of the present application can separate the active material layer 20 and the metal layer 12 while protecting the metal layer 12, reducing the cracks generated during the rolling of the metal layer 12, and being beneficial to improving the current-carrying capacity of the metal layer 12.

[0553] In some embodiments, along the direction from the conductive main body portion 13 to the conductive portion 14, the conductive protective layer 60 protrudes from the end face of the active material layer 20 facing the protruding portion 1421.

[0554] The conductive protective layer 60 protrudes from the active material layer 20, and the conductive protective layer 60 can completely separate the metal layer 12 and the active material layer 20. In addition, it can provide an epitaxial space during the rolling process of the active material layer 20, which is beneficial to the subsequent conductive protective layer 60 being able to completely separate the metal layer 12 and the active material layer 20.

[0555] By adopting the technical solution of this embodiment, the conductive protective layer 60 can completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 60 has a better protective ability for the metal layer 12, and the first electrode tab 1 has a better current-carrying capacity, which is beneficial to improving the fast charging performance and use reliability of the battery cell 100.

[0556] In some embodiments, along the direction from the conductive main body portion 13 to the conductive portion 14, the protruding distance range of the conductive protective layer 60 from the end face of the active material layer 20 facing the protruding portion 1421 is 0.3 mm to 0.8 mm.

[0557] The protruding distance of the conductive protective layer 60 from the end face of the active material layer 20 facing the protruding portion 1421 is S 3 , where 0.3 mm ≤ S 3 ≤ 0.8 mm, and the value of S 3 can be 0.3 mm, 0.8 mm, and any value between 0.3 mm and 0.8 mm. For example: S 3 The value can be but is not limited to 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm.

[0558] S 3 ≥ 0.3 mm design can enable the conductive protective layer 60 to completely separate the active material layer 20 and the metal layer 12. The conductive protective layer 60 has a better protective ability for the metal layer 12, and the first electrode tab 1 has a better current-carrying capacity, which is beneficial to improving the fast charging performance and use reliability of the battery cell 100; S 3The design with a thickness ≤ 0.8 mm ensures that the conductive protective layer 60 is not too large, thus not occupying excessive space, which is conducive to saving the internal space of the battery cell 100 and improving the energy density of the battery cell 100.

[0559] By adopting the technical solution of this embodiment, the overcurrent capacity and energy density of the battery cell 100 can be better balanced.

[0560] In some embodiments, along the first direction, the conductive protective layer 60 and the first welding mark 51 are arranged at intervals.

[0561] In some examples, the conductive protective layer 60 and the first connecting portion 31 are arranged at intervals, and the first insulating portion 41 covers the part of the conductive protective layer 60 located between the first connecting portion 31 and the active material layer 20.

[0562] By adopting the technical solution of this embodiment, the first connecting portion 31 will not be welded to the conductive protective layer 60, which can reduce risks such as false soldering and is conducive to improving the welding reliability between the first connecting portion 31 and the metal layer 12.

[0563] In some embodiments, the conductive protective layer 60 includes a first protective portion 61 and a second protective portion 62. The first protective portion 61 covers the conductive main body portion 13, and the second protective portion 62 covers at least part of the conductive portion 14; wherein, the thickness of the second protective portion 62 is less than the thickness of the first protective portion 61.

[0564] The first protective portion 61 may refer to the part of the conductive protective portion covering the conductive main body portion 13, and the second protective portion 62 may refer to the part of the conductive protective portion covering the conductive portion 14. Among them, the second protective portion 62 may cover a part of the conductive portion 14 or the entire conductive portion 14.

[0565] By adopting the technical solution of this embodiment, the thickness of the second protective portion 62 is less than the thickness of the first protective portion 61, which is conducive to reducing the sum of the thicknesses of the first protective portion 61 and the conductive main body portion 13 approaching the sum of the thicknesses of the second protective portion 62 and the conductive portion 14, and is conducive to the surface of the conductive protective portion facing away from the metal layer 12 approaching a plane, thereby being conducive to reducing rolling damage and improving the overcurrent capacity of the metal layer 12; in addition, it can also reduce the problem of winding bulging of the current collector 10.

[0566] In some embodiments, the conductive portion 14 includes a first main body segment 143 and a first transition segment 144. The first transition segment 144 is connected between the first main body segment 143 and the conductive main body portion 13. The thickness of the first transition segment 144 is greater than the thickness of the conductive main body portion 13; the thickness of the first main body segment 143 is greater than the thickness of the first transition segment 144; the second protection portion 62 includes a second main body segment 621 and a second transition segment 622. The second transition segment 622 covers the first transition segment 144, and the second main body segment 621 covers at least part of the first main body segment 143. The thickness of the second transition segment 622 is less than the thickness of the first protection portion 61; the thickness of the second main body segment 621 is less than the thickness of the second transition segment 622.

[0567] According to the segmentation of the conductive main body segment and the first transition segment 144 of the conductive portion 14, the second protection portion 62 is divided into two segments. Among them, the segment covering the first main body segment 143 is the second main body segment 621, and the segment covering the first transition segment 144 is the second transition segment 622. Among them, the second main body segment 621 can cover a part of the first main body segment 143 or the entire first main body segment 143.

[0568] The thickness of the second transition segment 622 is less than the thickness of the first protection portion 61; the thickness of the second main body segment 621 is less than the thickness of the second transition segment 622, so that the second main body segment 621 and the second transition segment 622 can compensate for the thickness difference between the first main body segment 143 and the first transition segment 144, which is beneficial to the surface of the second protection portion 62 facing away from the metal layer 12 to approach a plane.

[0569] Exemplarily, the first protection portion 61 and the conductive main body portion 13 are generally of an equal-thickness structure. The shape of the first protection portion 61 is adapted to the shape of the conductive main body portion 13. The shape of the second main body segment 621 is adapted to the shape of the first main body segment 143. The second main body segment 621 is also generally of an equal-thickness structure. The shape of the second transition segment 622 is adapted to the shape of the first transition segment 144, so as to better adapt to the thickness difference of the conductive portion 14.

[0570] By adopting the technical solution of this embodiment, the thickness change of the second protection portion 62 can compensate for the thickness change of the conductive portion 14, which is beneficial to the surface of the second protection portion 62 facing away from the metal layer 12 to approach a plane, beneficial to reducing roll pressing damage, and improving the current-carrying capacity of the metal layer 12; in addition, the winding bulge problem of the current collector 10 can also be reduced.

[0571] In some embodiments, along the direction from the conductive main body portion 13 to the conductive portion 14, the thickness of the first transition segment 144 is set to increase, and the thickness of the second transition segment 622 is set to decrease.

[0572] In the direction from the conductive main body portion 13 towards the conductive portion 14, the thickness of the first transition section 144 increases stepwise, and correspondingly, the thickness of the second transition section 622 decreases stepwise, and the absolute values of the thickness change amplitudes of the two are the same or approximately the same. In the direction from the conductive main body portion 13 towards the conductive portion 14, the thickness of the first transition section 144 increases slowly, and correspondingly, the thickness of the second transition section 622 decreases slowly, and the absolute values of the thickness change amplitudes of the two are the same or approximately the same.

[0573] By adopting the technical solution of this embodiment, the thickness change of the second protection portion 62 is adapted to the thickness of the conductive portion 14. The thickness change of the second protection portion 62 better compensates for the thickness change of the conductive portion 14, which is more conducive to the surface of the second protection portion 62 facing away from the metal layer 12 approaching a plane, is conducive to reducing rolling damage, and improving the current-carrying capacity of the metal layer 12; in addition, the problem of winding bulging of the current collector 10 can also be reduced.

[0574] In some embodiments, the thickness of the second main body section 621 is t 5 , and the thickness of the first protection portion 61 is t 6 , where 0.03 ≤ t 5 / t 6 ≤ 0.95.

[0575] t 5 / t 6 , may refer to the ratio of the thickness of the second main body section 621 to the thickness of the first protection portion 61, which can characterize the degree of thinning of the second main body section 621 relative to the first protection portion 61.

[0576] 0.03 ≤ t 5 / t 6 ≤ 0.95. It can be understood that the value of t 5 / t 6 can be 0.03, 0.95, and any value between 0.03 and 0.95; for example, the value of t 5 / t 6 can be but is not limited to 0.03, 0.1, 0.125, 0.15, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95.

[0577] By adopting the technical solution of this embodiment, with the design of 0.03 ≤ t 5 / t 6 ≤ 0.95, the degree of thinning of the conductive protection layer 60 is reasonable, which can better match the degree of thickening of the conductive portion 14, is conducive to the surface of the second protection portion 62 facing away from the metal layer 12 approaching a plane, is conducive to reducing rolling damage, and improving the current-carrying capacity of the metal layer 12.

[0578] In some embodiments, 0.125≤t 5 / t 6 ≤0.8.

[0579] By adopting the technical solution of this embodiment, 0.03≤t 5 / t 6 ≤0.95, the thinning degree of the conductive protective layer 60 is more reasonable, which can better adapt to the thickening degree of the conductive part 14, which is beneficial for the surface of the second protective part 62 facing away from the metal layer 12 to be close to the plane, which is beneficial for reducing rolling damage and improving the current carrying capacity of the metal layer 12.

[0580] In some embodiments, the thickness of the second main body segment 621 is t 5 , where 0.5μm≤t 5 ≤4μm.

[0581] 0.5μm≤t 5 ≤4μm, it is understandable that t 5 The value of can be 0.5 μm, 4 μm, and any value between 0.5 μm and 4 μm; for example, t 5 The value of can be, but is not limited to, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, and 5 μm.

[0582] By adopting the technical solution of this embodiment, 0.5μm≤t 5 The setting of ≤4μm allows the second main segment 621 to have a certain thickness, thereby reducing the risk of cracking of the metal layer 12; in addition, the second main segment 621 will not be too thick to cause the second main segment 621 to protrude from the first protective portion 61 away from the metal layer 12, and material accumulation and production costs can also be reduced.

[0583] In some embodiments, 1 μm ≤ t 5 ≤2μm.

[0584] By adopting the technical solution of this embodiment, 1μm≤t 5 The setting of ≤2 μm enables the second main body segment 621 to have a more reasonable thickness, thereby better reducing the risk of cracking of the metal layer 12 and the manufacturing cost.

[0585] In some embodiments, the insulating base 11 includes a first insulating base 111 and a second insulating base 112, the conductive body 13 covers the first insulating base 111, and the conductive part 14 covers the second insulating base 112; the thickness of the conductive body 13 is t 1 , the thickness of the conductive portion 14 is t 4 , the thickness of the first protection portion 61 is t 6 , the minimum thickness of the second protection portion 62 is t7 , the thickness of the first insulating base 111 is t 8 , the thickness of the second insulating base 112 is t 9 , where, -4μm ≤ (t 1 + t 6 + t 8 / 2) - (t 4 + t 7 + t 9 / 2) ≤ 4μm.

[0586] The insulating substrate 11 is divided into two parts. The part covering the conductive main body part 13 is the first insulating base 111, and the part covering the conductive part 14 is the second insulating base 112; the insulating substrate 11 can be generally an equal-thickness structure, and the thickness t of the first insulating substrate 11 8 is equal to the thickness t of the second insulating base 112 9 . The insulating substrate 11 can also be in a stepped structure, and the thickness t of the first insulating substrate 11 8 is greater than or less than the thickness t of the second insulating base 112 9 .

[0587] The second protection part 62 is generally an equal-thickness structure, and the minimum thickness t of the second protection part 62 7 is equal to the thickness of the second protection part 62; along the direction from the conductive main body part 13 to the conductive part 14, the thickness of the second protection part 62 gradually decreases, and the minimum thickness t of the second protection part 62 7 is equal to the thickness of the end of the second protection part 62 away from the first protection part 61; for example, the minimum thickness t of the second protection part 62 7 is equal to the thickness t of the second main body segment 621 5 .

[0588] t 1 + t 6 + t 8 / 2 can refer to half of the thickness of the current collector 10 at the conductive main body part 13; t 4 + t 7 + t 9 / 2 can refer to half of the thickness of the current collector 10 at the conductive part 14.

[0589] -4μm ≤ (t 1 + t 6 + t 8 / 2) - (t 4 + t 7 + t 9 / 2) ≤ 4μm, it can be understood that (t 1 + t 6 + t 8 / 2) - (t 4 + t7 +t 9 The value of / 2) can be -4 μm, 4 μm, or any value between -4 μm and 4 μm; for example, the value of t 5 can be but is not limited to -4 μm, -3 μm, -2 μm, -1 μm, 0 μm, 1 μm, 2 μm, 3 μm, 4 μm.

[0590] By adopting the technical solution of this embodiment, -4 μm ≤ (t 1 +t 6 +t 8 / 2) - (t 4 +t 7 +t 9 / 2) ≤ 4 μm is designed such that the half-thickness of the current collector 10 at the conductive main body portion 13 and the half-thickness of the current collector 10 at the conductive portion 14 do not differ much, which is beneficial for the surface of the conductive protective layer 60 facing away from the metal layer 12 to be close to a plane, beneficial for reducing rolling damage, and improving the current-carrying capacity of the metal layer 12; in addition, the edge swelling of the electrode assembly 101 can also be reduced.

[0591] In some embodiments, -2 μm ≤ (t 1 +t 6 +t 8 / 2) - (t 2 +t 7 +t 8 / 2) ≤ 2 μm.

[0592] By adopting the technical solution of this embodiment, -2 μm ≤ (t 1 +t 6 +t 8 / 2) - (t 2 +t 7 +t 8 / 2) ≤ 2 μm is designed such that the half-thickness of the current collector 10 at the conductive main body portion 13 and the half-thickness of the current collector 10 at the conductive portion 14 are closer, which is more beneficial for the surface of the conductive protective layer 60 facing away from the metal layer 12 to be close to a plane, beneficial for reducing rolling damage, and improving the current-carrying capacity of the metal layer 12.

[0593] In some embodiments, the thickness of the second insulating base 112 is less than the thickness of the first insulating base 111.

[0594] By adopting the technical solution of this embodiment, the thickness of the second insulating base 112 is less than the thickness of the first insulating base 111, such that the sum of the thickness of the second insulating base 112 and the conductive portion 14 is close to the sum of the thickness of the first insulating base 111 and the conductive main body portion 13, which is beneficial for the surface of the metal layer 12 facing away from the insulating substrate 11 to be close to a plane, beneficial for reducing rolling damage, and improving the current-carrying capacity of the metal layer 12.

[0595] In some embodiments, referring to Figure 3 As shown, the outer shell 200 includes a housing 202 and an end cap 201. The end cap 201 is disposed at the opening of the housing 202. The housing 202 and the end cap 201 enclose a receiving cavity. The electrode assembly 101 is received in the receiving cavity. At least one of the housing 202 and the end cap 201 is provided with an electrode lead-out portion 2011.

[0596] The electrode lead-out portion 2011 can be disposed on the housing 202, or on the end cap 201, or both the end cap 201 and the housing 202 are provided with the electrode lead-out portion 2011.

[0597] By adopting the technical solution of this embodiment, the outer shell 200 adopts the structure of the end cap 201 and the housing 202. The electrode assembly 101 is easily loaded into the outer shell 200, which facilitates the assembly of the battery cell 100 and is beneficial to reducing the manufacturing cost.

[0598] In some embodiments, the capacity of the battery cell 100 is greater than or equal to 20 A·h.

[0599] The capacity of the battery cell 100 is one of the important performance indicators for measuring the performance of the battery cell 100. It represents the amount of electricity discharged by the battery device 1100 under certain conditions (discharge rate, temperature, cut-off voltage, etc.), that is, the capacity of the battery cell 100, usually in ampere-hours (abbreviation, expressed as A·h, 1 A·h = 3600 C). Exemplarily, the capacity of the battery cell 100 can be directly read from the identification member of the battery cell 100.

[0600] When the capacity of the battery cell 100 is greater than or equal to 20 A·h, the capacity of the battery cell 100 is relatively high, and better requirements are imposed on the overcurrent capacity and use reliability of the electrode sheets in the battery cell 100. For the battery cell 100 of the embodiment of the present application, the metal layer 12 adopts the thickened structure form of the conductive portion 14, which can better meet the use requirements of the battery cell 100 with a capacity greater than or equal to 20 A·h.

[0601] In some embodiments, the first electrode sheet 1 is a positive electrode sheet, and the active material of the active material layer 20 contains Ni (nickel) element.

[0602] After adding the Ni (nickel) element to the active material layer 20, the energy density of the battery cell 100 can be improved. When the energy density of the battery cell 100 is high, after the burr of the current collector 10 pierces the separator and contacts the negative electrode sheet to cause a short circuit, the battery cell 100 is prone to thermal runaway.

[0603] By adopting the technical solution of this embodiment, the active material of the active material layer 20 contains Ni (nickel) element, which can improve the energy density of the battery cell 100. In addition, the positive electrode sheet adopts the structural form of the above-mentioned first electrode sheet 1, and the current collector 10 of the first electrode sheet 1 adopts the structural form of the composite current collector 10, which can reduce the risk of internal short circuit of the battery cell 100 and reduce the risk of thermal runaway of the battery cell 100.

[0604] In some embodiments, the material of the metal layer 12 includes one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0605] By adopting the technical solution of this embodiment, the metal layer 12 adopts the above-mentioned material, which is beneficial to improving the performance of the battery cell 100.

[0606] The battery cell 100 of the present application will be described below in conjunction with some embodiments.

[0607] Embodiment 1

[0608] In this embodiment, referring to Figures 3 - 10 As shown, the battery cell 100 includes an end cap 201, a housing 202 and an electrode assembly 101. The electrode assembly 101 is installed at the housing 202, and the end cap 201 covers the opening of the housing 202 to seal the housing 202. The electrode assembly 101 includes a first electrode sheet 1, a second electrode sheet 2 and a separator 3 wound around. The separator 3 is located between the first electrode sheet 1 and the second electrode sheet 2. The polarities of the first electrode sheet 1 and the second electrode sheet 2 are opposite. Among them, the first electrode sheet 1 can be a positive electrode sheet, the second electrode sheet 2 is a negative electrode sheet, or the first electrode sheet 1 is a negative electrode sheet and the second electrode sheet 2 is a positive electrode sheet.

[0609] In this embodiment, the end cap 201 is provided with an electrode lead-out portion 2011. The first electrode sheet 1 includes a current collector 10, an active material layer 20 and a conductive member 30. The current collector 10 includes an insulating substrate 11 and a metal layer 12. The insulating substrate 11, the metal layer 12 and the active material layer 20 are stacked along the thickness direction of the current collector 10. At least part of the metal layer 12 is located between the insulating substrate 11 and the active material layer 20; wherein, the metal layer 12 includes a conductive main body portion 13 and a conductive portion 14 extending from the conductive main body portion 13 in the first direction. The thickness of the conductive portion 14 is greater than the thickness of the conductive main body portion 13.

[0610] In this embodiment, the conductive part 14 includes a first conductive part 141 and a second conductive part 142. The first conductive part 141 is connected between the second conductive part 142 and the conductive main body part 13. The active material layer 20 includes a connected first active material part 21 and a second active material part 22. The thickness of the first active material part 21 is less than that of the second active material part 22. A part of the first active material part 21 and the second active material part 22 covers the first conductive part 141, and another part of the second active material part 22 covers the conductive main body part 13.

[0611] In this embodiment, the second conductive part 142 includes a transition part 1422 and a plurality of protruding parts 1421 arranged at intervals along the second direction. The transition part 1422 is connected between the protruding part 1421 and the first conductive part 141. The protruding part 1421 includes a first protruding sub - part 14211 and a second protruding sub - part 14212. The first protruding sub - part 14211 is connected between the second protruding sub - part 14212 and the transition part 1422. Along the second direction, the size of the first protruding sub - part 14211 is larger than that of the second protruding sub - part 14212.

[0612] The first connection part 31 of the conductive member 30 is welded to the connection between the first protruding sub - part 14211 and the second protruding sub - part 14212 to form a first welding mark part 511. The second connection part 32 of the conductive member 30 is welded to the electrode lead - out part 2011, and the first welding mark part 511 forms a first welding mark 51.

[0613] In this embodiment, the electrode assembly 101 further includes an insulating part 40. The insulating part 40 includes a first insulating part 41. The first insulating part 41 covers the end of the second protruding sub - part 14212 close to the active material layer 20 and the transition part 1422.

[0614] Embodiment Two

[0615] The difference between this embodiment and Embodiment One is as follows: Refer to Figures 11 - 17 As shown, the first connection part 31 of the conductive member 30 is welded to the surface of the protruding part 1421 facing away from the insulating base 11 to form a first welding mark part 511. The second connection part 32 of the conductive member 30 is welded to the transition part 1422 to form a second welding mark part 512. The second welding mark part 512 and the first welding mark part 511 together form a first welding mark 51.

[0616] In this embodiment, one side of the second insulating part 42 of the insulating part 40 covers the first welding mark 51 and the second welding mark 52, and the other side of the second insulating part 42 of the insulating part 40 covers the first insulating part 41.

[0617] Embodiment Three

[0618] The difference between this embodiment and Embodiment Two is as follows: Refer to Figures 18 - 21As shown, the insulating member 40 includes a second insulating portion 42. One side of the second insulating portion 42 covers the first solder mark 51, and the other side of the second insulating portion 42 covers the first active material portion 21 of the active material layer 20.

[0619] In some embodiments, referring to Figure 2 As shown, a battery device 1100 is provided, including the battery cell 100 of the above embodiment.

[0620] The battery device 1100 of the embodiment of the present application uses the above battery cell 100. The fast charging performance and reliability of the battery cell 100 are good, which is beneficial to improving the fast charging performance and reliability of the battery device 1100, and is also beneficial to improving the reliability of the battery device 1100.

[0621] In some embodiments, referring to Figure 1 As shown, an electrical device is provided, including the battery device 1100 of the above embodiment.

[0622] The electrical device of the embodiment of the present application uses the above battery device 1100. The fast charging performance and reliability of the battery device 1100 are good, which is beneficial to improving the endurance of the electrical device and is also beneficial to improving the reliability of the electrical device.

[0623] The descriptions of the above embodiments tend to emphasize the differences between the embodiments. The same or similar parts can be referred to each other. For the sake of brevity, they will not be repeated herein.

[0624] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A housing having an electrode lead-out portion; an electrode assembly, at least partially disposed in the housing; the electrode assembly comprises a first pole piece, the first pole piece comprises 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 are stacked along the thickness direction of the current collector, and at least a portion of the metal layer is located between the insulating substrate and the active material layer; The metal layer includes a conductive main body and a conductive part extending from the conductive main body along a first direction, the first direction is perpendicular to the thickness direction of the current collector, at least part of the conductive main body is covered with the active material layer, at least part of the conductive part is not covered with the active material layer, and the conductive part is connected to the electrode lead-out part; Along the thickness direction of the current collector, the thickness of the conductive portion is greater than the thickness of the conductive main body portion.

2. The battery cell according to claim 1, characterized in that: A surface of the conductive portion facing away from the insulating base is farther away from the insulating base than a surface of the conductive body portion facing away from the insulating base.

3. The battery cell according to claim 1, characterized in that: The conductive part includes a first conductive part and a second conductive part arranged along the first direction, the first conductive part is connected between the second conductive part and the conductive main body part, the first conductive part is covered with the active material layer, the second conductive part is not covered with the active material layer, and the second conductive part is connected to the electrode lead-out part.

4. The battery cell according to claim 3, 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 connected to the second active material portion, the thickness of the first active material portion is less than the thickness of the second active material portion, the first active material portion at least partially covers the first conductive portion, and the second active material portion at least partially covers the conductive main body portion.

5. The battery cell according to claim 4, characterized in that: A surface of the first active material portion facing away from the insulating base is closer to the insulating base than a surface of the second active material portion facing away from the insulating base.

6. The battery cell according to claim 4, characterized in that: The second active material portion covers a portion of the first conductive portion, and the first active material portion covers the remaining portion of the first conductive portion.

7. The battery cell according to claim 6, characterized in that: Along the first direction, a size of a portion of the first conductive portion covered by the second active material portion is W1, a size of a portion of the first conductive portion covered by the first active material portion is W2, and W1 ≥ W2.

8. The battery cell according to claim 4, characterized in that: The thickness of the conductive body portion is t1, the maximum thickness of the first conductive portion is t2, and the thickness of the second active material portion is t3, wherein 0.002≤(t2-t1) / t3≤0.08; optionally, 0.003≤(t2-t1) / t3≤0.

06.

9. The battery cell according to claim 8, characterized in that: 60μm≤t3≤250μm; optionally, 80μm≤t3≤180μm.

10. The battery cell according to any one of claims 3 to 9, characterized in that: Along the first direction, a size of the first conductive portion is W3, and a size of the conductive portion is W4, wherein W3 / W4≤0.

4.

11. The battery cell according to any one of claims 3 to 9, characterized in that: Along the first direction, the size of the first conductive portion is W3, and the size of the conductive portion is W4. Among them, 2mm≤W4-W3≤10mm, optionally, 3mm≤W4-W3≤6mm.

12. The battery cell according to any one of claims 3 to 9, characterized in that: Along the first direction, a size of the first conductive portion is W3, and a size of the conductive main body portion is W5, wherein W3 / (W3+W5)≤0.

45.

13. The battery cell according to any one of claims 3 to 9, characterized in that: Along the first direction, a size of the first conductive portion is W3, wherein 10 mm≤W3≤100 mm.

14. The battery cell according to any one of claims 3 to 9, characterized in that: The second conductive part includes at least one protrusion, which is connected to the first conductive part. Along a second direction, the size of the protrusion is smaller than that of the conductive main body, and the second direction is perpendicular to the thickness direction of the current collector and the first direction.

15. The battery cell according to claim 14, 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 conductive portion; along the second direction, a size of the first protruding sub-portion is greater than a size of the second protruding sub-portion.

16. The battery cell according to claim 14, characterized in that: There are multiple protrusions, and the multiple protrusions are arranged at intervals along the second direction. Along the second direction, the sum of the sizes of all the protrusions is smaller than the size of the conductive body.

17. The battery cell according to claim 14, characterized in that: The second conductive portion further includes a transition portion, which is connected between the protruding portion and the first conductive portion. Along the second direction, a size of the transition portion is greater than a sum of sizes of all the protruding portions.

18. The battery cell according to claim 17, characterized in that: Along the second direction, the size of the conductive body portion is L1, the size of the transition portion is L2, and 0.8≤L2 / L1≤1.

19. The battery cell according to any one of claims 3 to 9, characterized in that: The first pole piece also includes a conductive component, which includes a first connecting portion and a second connecting portion arranged along the first direction, the first connecting portion is connected to the second connecting portion, the first connecting portion is connected to the surface of the second conductive portion facing away from the insulating substrate, the second connecting portion is located on the side of the second conductive portion facing away from the first conductive portion, and the second connecting portion is connected to the electrode lead-out portion.

20. The battery cell according to claim 19, characterized in that: Along the first direction, the first connection portion is spaced apart from the active material layer.

21. The battery cell according to claim 20, characterized in that: The first connecting portion is welded to the surface of the second conductive portion facing away from the insulating substrate to form a first weld mark.

22. The battery cell according to claim 21, characterized in that: The second conductive part includes at least one protrusion, the protrusion is connected to the first conductive part, and along the second direction, the size of the protrusion is smaller than the size of the conductive main body; The second direction is perpendicular to the thickness direction of the current collector and the first direction; The first weld print includes a first weld print portion, and the first connection portion is welded to a surface of the protruding portion facing away from the insulating substrate to form the first weld print portion.

23. The battery cell according to claim 22, 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 conductive portion; along the second direction, the size of the first protruding sub-portion is larger than the size of the second protruding sub-portion; The first weld print portion includes a first weld print sub-portion, and the first connecting portion is welded to the first protruding sub-portion to form the first weld print sub-portion; And / or, the first weld print portion further includes a second weld print sub-portion, and the first connection portion is welded to a surface of the second protruding sub-portion facing away from the insulating substrate to form the second weld print sub-portion.

24. The battery cell according to claim 22, characterized in that: There are multiple protrusions, and the multiple protrusions are arranged at intervals along the second direction; The first connection portion includes a plurality of first connection sub-portions, the plurality of first connection sub-portions are arranged at intervals along the second direction, the number of the second connection portions is multiple, and each of the first connection sub-portions is connected to each of the second connection portions in a one-to-one correspondence; The first connecting sub-portions are welded one by one to the surface of the protruding portions facing away from the insulating substrate.

25. The battery cell according to any one of claims 21 to 24, characterized in that: The second conductive portion includes a transition portion and at least one protruding portion, the transition portion is connected between the first conductive portion and the protruding portion, and along a second direction, a size of the transition portion is greater than the sum of sizes of all the protruding portions; the second direction is perpendicular to the thickness direction of the current collector and the first direction; The first weld print further includes a second weld print portion, and the first connection portion is welded to a surface of the transition portion facing away from the insulating substrate to form the second weld print portion.

26. The battery cell according to claim 25, characterized in that: Along the second direction, the size of the transition portion is L2, the size of the second weld portion is L3, and 0.8≤L3 / L2≤1.

27. The battery cell according to claim 25, characterized in that: There are multiple protrusions, and the multiple protrusions are arranged at intervals along the second direction; The first connecting portion includes a second connecting sub-portion and a plurality of first connecting sub-portions, the plurality of first connecting sub-portions are arranged at intervals along the second direction, and each of the first connecting sub-portions covers each of the protruding portions in a one-to-one correspondence; There are multiple second connection parts, and along the first direction, one side of each first connection sub-part is connected to each second connection part in a one-to-one correspondence, and the other side of each first connection sub-part is connected to the second connection sub-part, and the second connection sub-parts are continuously arranged along the second direction; The second connecting sub-portion is welded to a surface of the transition portion facing away from the insulating substrate.

28. The battery cell according to any one of claims 21 to 24, characterized in that: The electrode assembly further includes an insulating member, which includes a first insulating portion, the first insulating portion covers a surface of the second conductive portion facing away from the insulating substrate, and the entire first insulating portion is located between the first weld mark and the active material layer.

29. The battery cell according to claim 28, characterized in that: The first insulating portion is located between the first connecting portion and the active material layer.

30. The battery cell according to claim 29, characterized in that: The insulating member further includes a second insulating portion, at least a portion of the second insulating portion covers the first weld mark.

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

32. The battery cell according to claim 21, characterized in that: The electrode assembly further includes an insulating member, wherein the insulating member includes a second insulating portion, and at least a portion of the second insulating portion covers the first weld mark.

33. The battery cell according to claim 32, characterized in that: Along the first direction, one side of the second insulating portion covers the first weld mark, and the other side of the second insulating portion covers at least a portion of the active material layer.

34. The battery cell according to any one of claims 30 to 33, characterized in that: The number of the metal layers is two, and the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector. The number of the active material layers is two, and the two active material layers cover the two metal layers respectively. There are two conductive members, and the first connecting parts of the two conductive members are respectively welded to the second conductive parts of the two metal layers to form two first weld marks; The number of the insulating members is two, and the second insulating parts of the two insulating members respectively cover at least a portion of the two first weld marks.

35. The battery cell according to claim 34, characterized in that: The second insulating part includes a first part and a second part connected to each other, the first part covers the first weld mark and points to the conductive part along the conductive main body, the second part protrudes from the side of the second conductive part, and the second part is located on the side of the second connecting part along the second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

36. The battery cell according to claim 35, characterized in that: The second parts of the two insulating members are in contact with each other.

37. The battery cell according to claim 34, characterized in that: The second connection portions of the two conductive members are welded to form a second weld mark.

38. The battery cell according to claim 37, characterized in that: The second insulating portion covers the second welding mark and is along the direction of the conductive body portion pointing to the conductive portion. The second insulating portion protrudes from the edge of the second welding mark facing away from the conductive body portion.

39. The battery cell according to claim 28, characterized in that: The electrode assembly includes a second pole piece with opposite polarity to the first pole piece, the second pole piece includes a main functional portion and a pole ear portion, the pole ear portion protrudes from the main functional portion along the first direction; along the direction from the conductive main portion to the conductive portion, the main functional portion protrudes from the end surface of the insulating member facing the active material layer, and the main functional portion does not protrude from the end surface of the insulating member away from the active material layer.

40. The battery cell according to claim 28, characterized in that: Along the first direction, a size of a portion of the insulating member covering the active material layer is H, wherein 0.2 mm ≤ H ≤ 1.0 mm, and optionally, 0.3 mm ≤ H ≤ 0.8 mm.

41. The battery cell according to any one of claims 21 to 24, characterized in that: Along the first direction, the distance between the first weld mark and the active material layer is S1, wherein 0.5 mm≤S1≤5 mm, optionally, 0.5 mm≤S1≤2.8 mm.

42. The battery cell according to any one of claims 21 to 24, characterized in that: Along the first direction, a distance between the first weld mark and an end surface of the first connecting portion facing the active material layer is S2, wherein 0.3 mm≤S2≤1.2 mm.

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

44. The battery cell according to any one of claims 1 to 9, characterized in that: Along the first direction, the size of the conductive portion is W4, and the size of the conductive main body portion is W5, wherein 0.01≤W4 / W5≤0.8; optionally, 0.05≤W4 / W5≤0.

6.

45. The battery cell according to any one of claims 1 to 9, characterized in that: The thickness of the conductive main body is t1, and the maximum thickness of the conductive part is t4, wherein 0.2 μm≤t4-t1≤4.5 μm, and optionally, 0.3 μm≤t4-t1≤1.75 μm.

46. ​​The battery cell according to any one of claims 1 to 9, characterized in that: The thickness of the conductive main body is t1, and the maximum thickness of the conductive part is t4, wherein 1<t1 / t4≤4, optionally, 1.5<t1 / t4≤2.

5.

47. The battery cell according to claim 46, characterized in that: The thickness of the conductive portion is t4, wherein 1 μm≤t4≤5 μm, optionally, 1.2 μm≤t4≤3.5 μm.

48. The battery cell according to any one of claims 1 to 9, characterized in that: The conductive part includes a first main section and a first transition section, the first transition section is connected between the first main section and the conductive main section, the thickness of the first transition section is greater than the thickness of the conductive main section; the thickness of the first main section is greater than the thickness of the first transition section; at least a portion of the first transition section is covered with the active material layer.

49. The battery cell according to claim 48, characterized in that: Along the direction from the conductive body portion to the conductive portion, the thickness of the first transition section is gradually increased.

50. The battery cell according to claim 48, characterized in that: Along the first direction, the size of the first transition section is W6, wherein 4mm≤W6≤50mm, optionally, 5mm≤W6≤34mm.

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

52. The battery cell according to claim 51, characterized in that: Along the direction from the conductive main body portion to the conductive portion, the conductive protection layer protrudes from the end surface of the active material layer toward the protruding portion by a distance ranging from 0.3 mm to 0.8 mm.

53. The battery cell according to claim 51, characterized in that: The conductive protective layer includes a first protective portion and a second protective portion, wherein the first protective portion covers the conductive main portion, and the second protective portion covers at least a portion of the conductive portion; wherein the thickness of the second protective portion is less than the thickness of the first protective portion.

54. The battery cell according to claim 53, characterized in that: The conductive part includes a first main body section and a first transition section, wherein the first transition section is connected between the first main body section and the conductive main body section, and the thickness of the first transition section is greater than the thickness of the conductive main body section; the thickness of the first main body section is greater than the thickness of the first transition section; The second protection portion includes a second main section and a second transition section, the second transition section covers the first transition section, the second main section covers at least part of the first main section, the thickness of the second transition section is less than the thickness of the first protection portion; the thickness of the second main section is less than the thickness of the second transition section.

55. The battery cell according to claim 54, characterized in that: Along the direction from the conductive main body to the conductive portion, the thickness of the first transition section is gradually increased, and the thickness of the second transition section is gradually decreased.

56. The battery cell according to claim 54, characterized in that: The thickness of the second main body segment is t5, and the thickness of the first protection portion is t6, wherein 0.03≤t5 / t6≤0.95, and optionally, 0.125≤t5 / t6≤0.

8.

57. The battery cell according to any one of claims 54 to 56, characterized in that: The thickness of the second main body segment is t5, wherein 0.5 μm≤t5≤4 μm, optionally, 1 μm≤t5≤2 μm.

58. The battery cell according to any one of claims 53 to 56, characterized in that: The insulating base includes a first insulating base and a second insulating base, the conductive main body covers the first insulating base, and the conductive part covers the second insulating base; the thickness of the conductive main body is t1, the thickness of the conductive part is t4, the thickness of the first protective part is t6, the minimum thickness of the second protective part is t7, the thickness of the first insulating base is t8, and the thickness of the second insulating base is t9, wherein, -4μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4μm, optionally, -2μm≤(t1+t6+t8 / 2)-(t2+t7+t8 / 2)≤2μm.

59. The battery cell according to claim 58, characterized in that: The thickness of the second insulating base is smaller than the thickness of the first insulating base.

60. The battery cell according to any one of claims 1 to 9, characterized in that: The shell includes a shell and an end cover, wherein the end cover is disposed at an opening of the shell, the shell and the end cover are arranged to form a receiving cavity, the electrode assembly is received in the receiving cavity, and at least one of the shell and the end cover is provided with the electrode lead-out portion.

61. The battery cell according to any one of claims 1 to 9, characterized in that: The capacity of the battery cell is greater than or equal to 20A·h.

62. The battery cell according to any one of claims 1 to 9, characterized in that: The first electrode sheet is a positive electrode sheet, and the active material of the active material layer contains Ni element.

63. The battery cell according to any one of claims 1 to 9, characterized in that: The material of the metal layer includes one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

64. A battery device, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 63.

65. An electrical device, characterized in that: Comprising the battery device of claim 64.

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