Battery monomer, battery device and electric device

Abstract

A battery cell (100), a battery device (1100) and a power utilization device, the battery cell (100) comprising a housing (200) and an electrode assembly (101), the housing (200) being provided with an electrode lead-out portion (2011); the electrode assembly (101) is arranged in the shell (200); the electrode assembly (101) comprises a first pole piece (1), the first pole piece (1) comprises a current collector (10) and an active material layer (20), the current collector (10) comprises 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 in the thickness direction of the current collector (10), and at least part of the metal layer (12) is located between the insulating substrate (11) and the active material layer (20); the metal layer (12) comprises a conductive main body part (13) and a conductive part (14) extending from the conductive main body part (13) along a first direction, the first direction is perpendicular to the thickness direction of the current collector (10), at least part of the conductive main body part (13) is covered with the active material layer (20), at least part of the conductive part (14) is not covered with the active material layer (20), and the conductive part (14) is connected with the electrode lead-out part (2011); the thickness of the conductive portion (14) is greater than the thickness of the conductive body portion (13).

Description

Battery cell, battery device and electric device TECHNICAL FIELD

[0001] The present application belongs to the technical field of battery fast charging, and particularly relates to a battery cell, a battery device and an electric device. BACKGROUND

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

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

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

[0005] CONTENT OF THE APPLICATION

[0006] The purpose of the embodiments of the present application is to provide a battery cell, a battery device and an electric device, which is beneficial to improve the fast charging performance of the battery cell.

[0007] The technical solution adopted by the embodiments of the present application is:

[0008] In some embodiments, a battery cell is provided, which includes a shell and an electrode assembly, the shell is provided with an electrode lead-out portion; at least part of the electrode assembly is arranged in the shell; the electrode assembly includes a first electrode sheet, the first electrode sheet includes a current collector and an active material layer, the current collector includes an insulating base body and a metal layer, the insulating base body, the metal layer and the active material layer are stacked along the thickness direction of the current collector, at least part of the metal layer is located between the insulating base body and the active material layer; wherein the metal layer includes a conductive main body portion and a conductive portion extending from the conductive main body portion 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 portion is covered with the active material layer, at least part of the conductive portion is not covered with the active material layer, the conductive portion is connected with 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.

[0009] By adopting the technical scheme of the embodiment, in the case of normal use of the battery monomer, the electrode lead-out part is used for inputting or outputting electric energy, thereby realizing charging and discharging of the battery monomer; the thickness of the conductive part connected with the electrode lead-out part is greater than the thickness of the conductive main part, thereby increasing the overcurrent area of the conductive part, improving the overcurrent capacity of the conductive part, reducing the heat generation of the battery monomer, and being beneficial to improving the charging and discharging efficiency of the battery monomer and improving the fast charging performance of the battery monomer; in addition, the current collector adopts the composite structure of the insulating base body and the metal layer, the thickness of the metal layer is small compared with the pure metal current collector, the burr generated in the manufacturing process of the current collector is small, the risk of internal short circuit of the battery monomer is reduced, and the use reliability of the battery monomer is improved; therefore, the battery monomer of the embodiment of the application can better balance the fast charging performance and the use reliability.

[0010] In some embodiments, the surface of the conductive part away from the insulating base body is farther away from the insulating base body than the surface of the conductive main part away from the insulating base body.

[0011] By adopting the technical scheme of the embodiment, the surface of the conductive part away from the insulating base body is protruded relative to the surface of the conductive main part away from the insulating base body, the space of the side of the conductive part away from the insulating base body can be utilized, the risk of thinning the insulating base body at the conductive part to accommodate the conductive part can be reduced, the structural strength of the insulating base body at the conductive part is improved, the structural strength of the current collector is improved, and the use reliability of the battery monomer is improved.

[0012] 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 part, the first conductive part is covered with an active material layer, the second conductive part is not covered with the active material layer, and the second conductive part is connected with the electrode lead-out part.

[0013] By adopting the technical scheme of the embodiment, the active material layer covers the first conductive part, which is beneficial to improving the electron transmission capacity 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 monomer; in addition, the conductive main part and the first conductive part are also covered with the active material layer, which is beneficial to improving the electron transmission capacity of the first electrode tab at the junction of the first conductive part and the conductive main part, reducing the resistance of the first electrode tab, and being beneficial to improving the fast charging performance of the battery monomer.

[0014] 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 with the second active material part, the thickness of the first active material part is less than the thickness 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 part.

[0015] By adopting the technical scheme of the embodiment, the first active material part is arranged, so that the rolling pressure on the edge of the active material layer is reduced, and the risk of cracking of the edge of the active material layer is reduced. In addition, at least part of the first active material part covers the first conductive part, which is conducive to reducing the overall thickness of the first pole piece at the first active material part, reducing the pressure on the edge of the active material layer, and further reducing the risk of cracking of the edge of the active material layer.

[0016] In some embodiments, the surface of the first active material part away from the insulating base is closer to the insulating base than the surface of the second active material part away from the insulating base.

[0017] By adopting the technical scheme of the embodiment, the rolling pressure on the first active material part is reduced, which is conducive to reducing the risk of cracking of the active material layer.

[0018] In some embodiments, the second active material part covers part of the first conductive part, and the first active material part covers other parts of the first conductive part.

[0019] By adopting the technical scheme of the embodiment, the second active material part covers the first conductive part, the first conductive part is covered with more active material, the electronic transmission capacity between the first conductive part and the active material layer is better, which is conducive to reducing the resistance between the active material layer and the first conductive part and improving the fast charging capability of the battery monomer.

[0020] In some embodiments, in the first direction, the size of the part of the first conductive part covered by the second active material part is W1, the size of the part of the first conductive part covered by the first active material part is W2, and W1≥W2.

[0021] By adopting the technical scheme of the 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 the first conductive part is covered with more active material, the electronic transmission capacity between the first conductive part and the active material layer is better, which is conducive to reducing the resistance between the active material layer and the first conductive part and improving the fast charging capability of the battery monomer.

[0022] In some embodiments, the thickness of the conductive main part is t1, the maximum thickness of the first conductive part is t2, and the thickness of the second active material part is t3, wherein 0.002≤(t2-t1) / t3≤0.08; optionally, 0.003≤(t2-t1) / t3≤0.06.

[0023] By adopting the technical scheme of the embodiment, the ratio of the thickness difference between the first conductive part and the conductive main part to the thickness of the second active material part is within a reasonable range, which improves the flatness of the surface of the active material layer away from the insulating base, and is conducive to improving the manufacturability of the first pole piece.

[0024] In some embodiments, 60 μm≤t3≤250 μm; optionally, 80 μm≤t3≤180 μm.

[0025] By adopting the technical solutions of this embodiment, the thickness of the second active material part is within a proper range, and the volume of the active material layer is properly set, which is conducive to improving the fast-charging performance and use reliability of the battery monomer and reducing the risk of ion release difficulty in the region of the active material layer close to the conductive layer, thereby improving the performance of the battery monomer.

[0026] In some embodiments, along the first direction, the size of the first conductive part is W3, and the size of the conductive part is W4, where W3 / W4≤0.4.

[0027] By adopting the technical solutions 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 properly set, which facilitates the connection of the second conductive part and the electrode lead-out part, and the first conductive part and the active material layer have good electron transmission capability, which is conducive to reducing the resistance of the first pole piece and improving the fast-charging performance of the battery monomer.

[0028] In some embodiments, along the first direction, the size of the first conductive part is W3, and the size of the conductive part is W4, where 2 mm≤W4-W3≤10 mm, and optionally, 3 mm≤W4-W3≤6 mm.

[0029] By adopting the technical solutions of this embodiment, along the first direction, the size of the second conductive part is within a proper range, which facilitates the connection of the second conductive part and the electrode lead-out part, and also reduces the occupation of too much space due to the too large size of the second conductive part along the first direction, which is conducive to improving the energy density of the battery monomer.

[0030] In some embodiments, along the first direction, the size of the first conductive part is W3, and the size of the conductive main part is W5, where W3 / (W3+W5)≤0.45.

[0031] By adopting the technical solutions of this embodiment, along the first direction, the ratio of the size of the first conductive part to the sum of the size of the first conductive part and the size of the conductive main part is within a proper range, and the first conductive part can cover the active material layer, which is conducive to reducing the internal resistance of the first pole piece and improving the fast-charging capability of the battery monomer; 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 the thickness of the conductive main part, which also reduces the risk of burr generation of the first pole piece at the first conductive part, and is conducive to improving the use reliability of the battery monomer.

[0032] In some embodiments, along the first direction, the size of the first conductive part is W3, where 10 mm≤W3≤100 mm.

[0033] By adopting the technical scheme of the embodiment, along the first direction, the size of the first conductive part is within a reasonable range, so that the active material layer and the first conductive part have good electron transmission capability, in addition, along the second direction, the first conductive part does not occupy a large area, and the thickness of the first conductive part is greater than the thickness of the conductive main part, which reduces the risk of burr of the first pole piece at the first conductive part, and is beneficial to improve the use reliability of the battery monomer.

[0034] In some embodiments, the second conductive part includes at least one protruding part, the protruding part is connected with the first conductive part, and along the second direction, the size of the protruding part is smaller than the size of the conductive main part, and the second direction is perpendicular to the thickness direction of the current collector and the first direction.

[0035] By adopting the technical scheme of the embodiment, along the second direction, the size of the protruding part is smaller than the size of the conductive main part, the protruding part is easy to be connected with the electrode lead-out part along with the bending of the conductive member, which is convenient for processing and manufacturing, and is also beneficial to reduce the space occupied after the bending of the conductive member, and is beneficial to improve the energy density of the battery monomer.

[0036] In some embodiments, the protruding part includes a first protruding sub-part and a second protruding sub-part, 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 greater than the size of the second protruding sub-part.

[0037] By adopting the technical scheme of the embodiment, along the second direction, the first protruding sub-part is large, the flow area of the first protruding sub-part is large and the flow capacity is strong, which is beneficial to reduce heat generation, and is beneficial to improve the fast charging performance and use reliability of the battery monomer.

[0038] In some embodiments, the number of the protruding parts is multiple, the multiple protruding parts are arranged at intervals along the second direction, and along the second direction, the sum of the sizes of all the protruding parts is smaller than the size of the conductive main part.

[0039] By adopting the technical scheme of the embodiment, the multiple protruding parts are arranged at intervals along the second direction, which is beneficial to divide the conductive main part into multiple regions along the second direction, and one region can correspond to one protruding part, and the electrons in each region can be transmitted to the electrode lead-out part through the corresponding protruding part, so that the electrons of the conductive main part are transmitted in regions, and the transmission path of the electrons in each region is short, which is beneficial to reduce the transmission distance of the electrons, reduce the overall resistance of the first pole piece, and improve the fast charging performance and use reliability of the battery monomer.

[0040] In some embodiments, the second conductive part further includes a transition part, the transition part is connected between the protruding part and the first conductive part, and along the second direction, the size of the transition part is greater than the sum of the sizes of all the protruding parts.

[0041] By adopting the technical scheme of the embodiment, the thickness of the transition part is greater than the thickness of the conductive main body part, and the size of the transition part along the second direction is large, and the flow capacity of the transition part is strong, which is beneficial to reduce heat generation and improve the fast charging performance and use reliability of the battery monomer.

[0042] In some embodiments, along the second direction, the size of the conductive main body part is L1, and the size of the transition part is L2, and 0.8≤L2 / L1≤1.

[0043] By adopting the technical scheme of the embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition part close to the size of the conductive main body part along the second direction, the size of the transition part is large, and the flow capacity of the transition part is better, which is beneficial to reduce heat generation and improve the fast charging performance and use reliability of the battery monomer.

[0044] In some embodiments, the first pole piece further comprises a conductive member, the conductive member comprising a first connecting part and a second connecting part arranged along the first direction, the first connecting part being connected to the second connecting part, the first connecting part being connected to the surface of the second conductive part away from the insulating base body, and the second connecting part being located at the side of the second conductive part away from the first conductive part, and the second connecting part being connected to the electrode lead-out part.

[0045] By adopting the technical scheme of the embodiment, the second connecting part protrudes out of the second conductive part, and the second connecting part can be conveniently connected to the electrode lead-out part, and the processing and manufacturing are more convenient.

[0046] In some embodiments, along the first direction, the first connecting part is arranged to be spaced apart from the active material layer.

[0047] By adopting the technical scheme of the embodiment, the first connecting part does not contact the active material layer, and the mutual influence between the two can be reduced, and the use reliability of the battery monomer is improved.

[0048] In some embodiments, the first connecting part is welded to the surface of the second conductive part away from the insulating base body and forms a first welding mark.

[0049] By adopting the technical scheme of the embodiment, the first connecting part is welded to the second conductive part, the conductive member is connected to the second conductive part in a welding manner, which is convenient for the manufacturing of the first pole piece; in addition, the thickness of the second conductive part is small, and the surface of the second conductive part away from the insulating base body is large, which is beneficial to improve the welding area between the first connecting part and the second conductive part, improve the flow area between the first connecting part and the second conductive part, improve the flow capacity of the first pole piece, and improve the fast charging performance and use reliability of the battery monomer; at the same time, the risk of false welding between the first connecting part and the second conductive part can be reduced, which is beneficial to improve the connection reliability of the second conductive part and the conductive member, improve the flow capacity of the first pole piece, and improve the fast charging performance and use reliability of the battery monomer.

[0050] In some embodiments, the second conductive part includes at least one protruding part connected to the first conductive part, the size of the protruding part in the second direction is smaller than the size of the conductive main part; the second direction is perpendicular to the thickness direction of the current collector and the first direction; the first solder print includes a first solder print part, and the first connecting part is soldered to the surface of the protruding part away from the insulating base and forms the first solder print part.

[0051] By adopting the technical scheme of this embodiment, the first connecting part and the protruding part are connected in a soldering manner, the connection manner is simple, and the first pole piece is easy to manufacture; in addition, the first connecting part and the protruding part can directly flow through the first solder print part, which is beneficial to improving the flow capacity between the first connecting part and the protruding part.

[0052] In some embodiments, the protruding part includes a first protruding subpart and a second protruding subpart, the first protruding subpart is connected between the second protruding subpart and the first conductive part; the size of the first protruding subpart in the second direction is greater than the size of the second protruding subpart; the first solder print part includes a first solder print subpart, and the first connecting part is soldered to the first protruding subpart and forms the first solder print subpart; and / or, the first solder print part further includes a second solder print subpart, and the first connecting part is soldered to the surface of the second protruding subpart away from the insulating base and forms the second solder print subpart.

[0053] By adopting the technical scheme of this embodiment, the soldering position can be flexibly set to meet different needs.

[0054] In some embodiments, the number of protruding parts is multiple, and the multiple protruding parts are arranged at intervals in the second direction; the first connecting part includes multiple first connecting subparts, the multiple first connecting subparts are arranged at intervals in the second direction, the number of second connecting parts is multiple, and each first connecting subpart is connected to each second connecting part in one-to-one correspondence; each first connecting subpart is soldered to the surface of each protruding part away from the insulating base in one-to-one correspondence.

[0055] By adopting the technical scheme of this embodiment, the multiple first connecting subparts of the first connecting part are arranged at intervals in the second direction, and there is a gap between the adjacent two first connecting subparts, which can reduce the required material of the first connecting part and reduce the manufacturing cost of the battery monomer.

[0056] In some embodiments, the second conductive part includes a transition part and at least one protruding part, the transition part is connected between the first conductive part and the protruding part, the size of the transition part in the second direction is greater than the sum of the sizes of all the protruding parts; the second direction is perpendicular to the thickness direction of the current collector and the first direction, and the first solder print further includes a second solder print part, and the first connecting part is soldered to the surface of the transition part away from the insulating base and forms the second solder print part.

[0057] By adopting the technical scheme of the embodiment, the first connecting part and the transition part are connected in a welding manner, the connection mode is simple, and the first pole piece is convenient to manufacture; in addition, along the second direction, the size of the transition part is large, the flow capacity of the transition part is good, the transition part can be directly used for flow between the first connecting part and the first conductive part, the flow pressure between the protruding part and the flow part can be reduced, even without the flow of the protruding part, the risk of heat generation is reduced, and the fast charging performance of the battery monomer is improved.

[0058] In some embodiments, along the second direction, the size of the transition part is L2, the size of the second welding mark part is L3, and 0.8≤L3 / L2≤1.

[0059] By adopting the technical scheme of the embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the second welding mark part larger along the second direction, which is beneficial to improve the welding area between the first connecting part and the transition part, improve the flow capacity of the connection part of the transition part, improve the flow capacity of the first pole piece, and improve the fast charging performance and use reliability of the battery monomer.

[0060] In some embodiments, the number of protruding parts is multiple, and the multiple protruding parts are arranged at intervals along the second direction; the first connecting part includes a second connecting subpart and multiple first connecting subparts, the multiple first connecting subparts are arranged at intervals along the second direction, and each first connecting subpart corresponds to each protruding part; the number of second connecting parts is multiple, and along the first direction, one side of each first connecting subpart is connected to each second connecting part, the other side of each first connecting subpart is connected to the second connecting subpart, and the second connecting subpart is arranged continuously along the second direction; and the second connecting subpart is welded to the surface of the transition part away from the insulating base.

[0061] By adopting the technical scheme of the embodiment, the second connecting subpart is arranged continuously along the second direction, the multiple first connecting subparts can be connected as a whole, the second connecting subpart can provide good support to the first connecting subpart, the risk of the first connecting subpart being inserted between the first pole piece and the second pole piece when being bent can be reduced, the short circuit risk can be reduced, and the use reliability of the battery monomer is improved; in addition, along the second direction, the size of the second connecting subpart is large, which is beneficial to improve the welding area between the second connecting subpart and the transition part, improve the flow capacity of the connection part of the transition part, improve the flow capacity of the first pole piece, and improve the fast charging performance and use reliability of the battery monomer.

[0062] In some embodiments, the electrode assembly further includes an insulating piece, and the insulating piece includes a first insulating part, the first insulating part covers the surface of the second conductive part away from the insulating base, and the entire first insulating part is located between the first welding mark and the active material layer.

[0063] By adopting the technical scheme of the embodiment, the first insulating part can insulate the surface of the second conductive part away from other components, which is beneficial to improve the use reliability of the battery monomer, and also beneficial to reduce the risk of virtual welding caused by welding the first connecting part to the first insulating part, improve the connection reliability of the first connecting part and the second conductive part, and improve the overcurrent capacity.

[0064] In some embodiments, the first insulating part is located between the first connecting part and the active material layer.

[0065] By adopting the technical scheme of the embodiment, the first insulating part can support the part of the second conductive part between the first connecting part and the active material layer, which can reduce the damage such as cracks and fractures of this part during the manufacturing process of the battery device, and is beneficial to improve the electronic transmission capacity of this part and improve the fast charging performance and use reliability of the battery monomer. In addition, the first insulating part can also insulate this part, reduce the short circuit risk of the battery monomer, and improve the use reliability of the battery monomer.

[0066] In some embodiments, the insulating piece further comprises a second insulating part, at least part of the second insulating part covers the first welding mark.

[0067] By adopting the technical scheme of the embodiment, the surface of the first welding mark will produce components such as sharp protrusions and metal debris, and the second insulating part covers the surface of the first welding mark, which can block the contact between the sharp protrusions and the metal debris and the second pole piece, reduce the short circuit risk of the battery monomer, and improve the use reliability of the battery monomer.

[0068] In some embodiments, along the first direction, one side of the second insulating part covers the first welding mark, and the other side of the second insulating part covers at least part of the first insulating part.

[0069] By adopting the technical scheme of the embodiment, the second insulating part and the first insulating part jointly cover the second conductive part, which can realize double-layer insulation, is beneficial to reduce the short circuit risk of the battery monomer, and is beneficial to improve the use reliability of the battery monomer.

[0070] In some embodiments, the electrode assembly further comprises an insulating piece, and the insulating piece comprises a second insulating part, at least part of the second insulating part covers the first welding mark.

[0071] By adopting the technical scheme of the embodiment, the surface of the first welding mark will produce components such as sharp protrusions and metal debris, and the second insulating part covers the surface of the first welding mark, which can block the contact between the sharp protrusions and the metal debris and the second pole piece, reduce the short circuit risk of the battery monomer, and improve the use reliability of the battery monomer.

[0072] In some embodiments, along the first direction, one side of the second insulating part covers the first solder print, and the other side of the second insulating part covers at least part of the active material layer.

[0073] By adopting the technical solutions of this embodiment, the second insulating part extends from the first solder print to the active material layer, the second insulating part has a wide coverage area, and the insulation effect is good.

[0074] In some embodiments, the number of metal layers is two, the two metal layers are arranged on opposite sides of the insulating base along the thickness direction of the current collector, the number of active material layers is two, the two active material layers respectively cover the two metal layers, the number of conductive members is two, the first connecting parts of the two conductive members are respectively soldered to the second conductive parts of the two metal layers and form two first solder prints, and the number of insulating pieces is two, the second insulating parts of the two insulating pieces respectively cover at least part of the two first solder prints.

[0075] By adopting the technical solutions of this embodiment, the first connecting parts of the two conductive members are respectively soldered to the metal layers located on opposite sides of the insulating base, and the second connecting parts of the two conductive members are located on the side of the second conductive part away from the first conductive part, so that the two conductive parts can be directly connected by the second connecting parts of the two conductive members, thereby breaking the insulation limitation of the insulating base, effectively improving the conductive capacity of the first pole piece, improving the fast-charging performance of the battery monomer, reducing heat generation, and improving the use reliability of the battery monomer.

[0076] 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 solder print, and along the direction in which the conductive main body part points to the conductive part, 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.

[0077] By adopting the technical solutions of this embodiment, along the direction in which the conductive main body part points to the conductive part, the metal debris and other components 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 pieces, so that the risk of metal debris falling into the electrode assembly can be reduced, and the risk of short circuit can be reduced.

[0078] In some embodiments, the second parts of the two insulating pieces are in contact with each other.

[0079] By adopting the technical solutions of this embodiment, after the second parts of the two insulating pieces are in contact with each other, the metal debris and other components at the side of the second conductive part can be covered, so that the metal debris and other components are not easy to fall into the electrode assembly, and the risk of short circuit of the battery monomer can be better reduced.

[0080] In some embodiments, the second connecting portions of the two conductive members are welded and form a second welding mark in a direction of the conductive main body portion pointing to the conductive portion.

[0081] By adopting the technical solutions of this embodiment, the second connecting portions of the two conductive members are welded, and the second conductive portions on the opposite sides of the insulating base are connected, thereby breaking the insulation limit of the insulating base, effectively improving the conductive capacity of the first tab, improving the fast-charging performance of the battery monomer, reducing heat generation, and improving the use reliability of the battery monomer.

[0082] In some embodiments, the second insulating portion covers the second welding mark and protrudes from the edge of the second welding mark away from the conductive main body portion in a direction of the conductive main body portion pointing to the conductive portion.

[0083] By adopting the technical solutions of this embodiment, the second insulating portion can completely cover the second welding mark, block the burrs, metal debris and other components on the second welding mark from piercing the separator to connect with the second tab, reduce the risk of short circuit, and improve the use reliability of the battery monomer.

[0084] In some embodiments, the electrode assembly includes a second tab opposite in polarity to the first tab, the second tab including a main functional portion and a tab portion, the tab portion protruding from the main functional portion in a first direction; in a direction of the conductive main body portion pointing to the conductive portion, the main functional portion protrudes from an end surface of the insulating member facing the active material layer, and the main functional portion does not protrude from an end surface of the insulating member away from the active material layer.

[0085] By adopting the technical solutions of this embodiment, the insulating member can block the burrs at the end surface of the main functional portion of the second tab close to the tab portion from piercing the separator to connect with the first tab, reduce the risk of short circuit between the first tab and the second tab, and be conducive to improving the use reliability of the battery monomer.

[0086] In some embodiments, the electrode assembly includes a second tab opposite in polarity to the first tab, the second tab including a main functional portion and a tab portion, the tab portion protruding from the main functional portion in a first direction; in a direction of the conductive main body portion pointing to the conductive portion, the main functional portion protrudes from an end surface of the conductive portion away from the conductive main body portion.

[0087] By adopting the technical solutions of this embodiment, the burrs at the end surface of the main functional portion of the second tab facing the tab portion correspond to the hollow area of the metal layer not extending out of the second connecting portion, which can also reduce the risk of short circuit of the battery monomer and improve the use reliability of the battery monomer.

[0088] In some embodiments, in the first direction, the insulating member covers a portion of the active material layer, and the size of the portion is H, where 0.2mm≤H≤1.0mm, and optionally, 0.3mm≤H≤0.8mm.

[0089] By adopting the technical scheme of the embodiment, along the first direction, the size of the part of the active material layer covered by the insulating member is reasonable, and the spurs of the active material layer close to the end of the conductive part and the energy density of the battery cell can be considered at the same time.

[0090] In some embodiments, along the first direction, the distance between the first welding mark and the active material layer is W, wherein 0.5mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm.

[0091] By adopting the technical scheme of the embodiment, the first welding mark will not be welded to the active material layer, reducing problems such as false welding, which is conducive to improving the connection reliability of the first connecting part 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 closer to the first welding mark. Therefore, under the condition that the size of the metal layer in the first direction is constant, the active material layer can cover a larger area, which is conducive to improving the energy density of the battery cell.

[0092] In some embodiments, along the first direction, the distance between the first welding mark and the end surface of the first connecting part facing the active material layer is S2, wherein 0.3mm≤S2≤1.2mm.

[0093] By adopting the technical scheme of the embodiment, the use reliability and energy density of the battery cell can be better considered.

[0094] In some embodiments, along the first direction, the size of the conductive part is W4, and the size of the conductive main part is W5, wherein 0.01≤W4 / W5≤0.8; and optionally, 0.05≤W4 / W5≤0.6.

[0095] By adopting the technical scheme of the embodiment, along the first direction, the ratio of the size of the conductive part to the size of the conductive main part is reasonably set, which can improve the overcurrent capacity at the conductive part, improve the fast charging performance and use reliability of the battery cell, and in addition, the size of the conductive part is not too large along the first direction, which is conducive to reducing the occupied space and weight of the conductive part, and is conducive to improving the energy density of the battery cell.

[0096] In some embodiments, the thickness of the conductive main part is t1, and the maximum thickness of the conductive part is t4, wherein 0.2μm≤t4-t1≤4.5μm, and optionally, 0.3μm≤t4-t1≤1.75μm.

[0097] By adopting the technical scheme of the embodiment, the difference between the maximum thickness of the conductive part and the thickness of the conductive main part is within a reasonable range, which can improve the overcurrent capacity at the conductive part, improve the fast charging performance and use reliability of the battery cell, and in addition, the thickness of the conductive part is not too large, which is conducive to reducing the occupied space and weight of the conductive part, and is conducive to improving the energy density of the battery cell.

[0098] In some embodiments, the thickness of the conductive main body part is t1, and the maximum thickness of the conductive part is t4, wherein 1 < t1 / t4 ≤ 4, and optionally, 1.5 < t1 / t4 ≤ 2.5.

[0099] By adopting the technical solutions 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, the overcurrent capacity at the conductive part can be improved, the fast-charging performance and use reliability of the battery monomer can be improved, in addition, the thickness of the conductive part is not too large, which is conducive to reducing the occupied space and weight of the conductive part, and is conducive to improving the energy density of the battery monomer.

[0100] In some embodiments, the thickness of the conductive part is t4, wherein 1 μm ≤ t4 ≤ 5 μm, and optionally, 1.2 μm ≤ t4 ≤ 3.5 μm.

[0101] By adopting the technical solutions of this embodiment, the thickness of the conductive part is reasonably designed, the overcurrent capacity at the conductive part can be improved, the fast-charging performance and use reliability of the battery monomer can be improved, in addition, the thickness of the conductive part is not too large, which is conducive to reducing the occupied space and weight of the conductive part, and is conducive to improving the energy density of the battery monomer.

[0102] In some embodiments, the conductive part includes a first main body segment and a first transition segment, the first transition segment is connected between the first main body segment and the conductive main body part, and the thickness of the first transition segment is greater than the thickness of the conductive main body part; the thickness of the first main body segment is greater than the thickness of the first transition segment; and at least part of the first transition segment is covered with an active material layer.

[0103] By adopting the technical solutions of this embodiment, the first transition segment is provided, which can reduce the stress concentration of the metal layer, can reduce the risk of cracks in the metal layer during the forming process, can improve the overcurrent capacity of the conductive part, and improve the fast-charging performance and use reliability of the battery monomer, and also facilitates processing and manufacturing.

[0104] In some embodiments, in the direction of the conductive main body part pointing to the conductive part, the thickness of the first transition segment is incrementally arranged.

[0105] By adopting the technical solutions of this embodiment, the stress concentration of the metal layer can be better reduced, the risk of cracks in the metal layer during the forming process can be better reduced, the overcurrent capacity of the conductive part can be improved, the fast-charging performance and use reliability of the battery monomer can be improved, and processing and manufacturing are also facilitated.

[0106] In some embodiments, in the first direction, the size of the first transition segment is W6, wherein 4 mm ≤ W6 ≤ 50 mm, and optionally, 5 mm ≤ W6 ≤ 34 mm.

[0107] By adopting the technical scheme of the embodiment, the size of the first transition section in the first direction is reasonably designed, the stress concentration of the metal layer can be reduced, the risk of cracks in the metal layer during forming can be reduced, the overcurrent capacity of the conductive part can be improved, the fast charging performance and use reliability of the battery monomer are improved, and the processing and manufacturing are also facilitated. In addition, the size of the first transition section in the first direction is not too large, the space and weight occupied by the conductive part are reduced, and the energy density of the battery monomer is improved.

[0108] In some embodiments, the first pole piece further comprises a conductive protective layer, at least part of the conductive protective layer is located between the active material layer and the metal layer.

[0109] By adopting the technical scheme of the embodiment, the conductive protective layer can separate the active material layer and the metal layer while protecting the metal layer, reducing the cracks generated by rolling the metal layer, and improving the overcurrent capacity of the metal layer.

[0110] In some embodiments, in the direction of the conductive main body part pointing to the conductive part, the conductive protective layer protrudes from the active material layer to the end face of the protruding part with a protruding distance range of 0.3mm-0.8mm.

[0111] By adopting the technical scheme of the embodiment, the overcurrent capacity and energy density of the battery monomer can be well balanced.

[0112] In some embodiments, the conductive protective layer comprises 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.

[0113] By adopting the technical scheme of the embodiment, the thickness of the second protective part is less than the thickness of the first protective part, which is beneficial to reduce the sum of the thickness of the first protective part and the conductive main body part close to the sum of the thickness of the second protective part and the conductive part, which is beneficial to the surface of the conductive protective part facing away from the metal layer to be close to a plane, thereby reducing the rolling damage and improving the overcurrent capacity of the metal layer; in addition, the winding bulging problem of the current collector can also be reduced.

[0114] In some embodiments, the conductive part comprises a first main section and a first transition section, the first transition section is connected between the first main section and the conductive main body part, the thickness of the first transition section is greater than the thickness of the conductive main body part; the thickness of the first main section is greater than the thickness of the first transition section; the second protective part comprises 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 protective part; the thickness of the second main section is less than the thickness of the second transition section.

[0115] By adopting the technical scheme of the embodiment, the thickness change of the second protective part can compensate for the thickness change of the conductive part, which is conducive to the second protective part's surface opposite to the metal layer being close to a plane, reducing the roll damage and improving the current-carrying capacity of the metal layer; in addition, the winding bulging problem of the current collector can also be reduced.

[0116] In some embodiments, in the direction pointing 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.

[0117] By adopting the technical scheme of the embodiment, the thickness change of the second protective part is adapted to the thickness of the conductive part, and the thickness change of the second protective part better compensates for the thickness change of the conductive part, which is more conducive to the second protective part's surface opposite to the metal layer being close to a plane, reducing the roll damage and improving the current-carrying capacity of the metal layer.

[0118] In some embodiments, the thickness of the second main body section is t5, and the thickness of the first protective part is t6, wherein 0.03≤t5 / t6≤0.95, and optionally, 0.125≤t5 / t6≤0.8.

[0119] By adopting the technical scheme of the embodiment, the ratio of the thickness of the second main body section to the thickness of the first protective part is within a reasonable range, the thinning degree of the conductive protective layer is reasonable, and the thickness change of the second protective part can be better adapted to the thickness change of the conductive part, which is conducive to the second protective part's surface opposite to the metal layer being close to a plane, reducing the roll damage and improving the current-carrying capacity of the metal layer.

[0120] In some embodiments, the thickness of the second main body section is t5, wherein 0.5μm≤t5≤4μm, and optionally, 1μm≤t5≤2μm.

[0121] By adopting the technical scheme of the embodiment, the thickness of the second main body section is set reasonably, which can reduce the risk of metal layer cracking; in addition, the second main body section will not protrude from the first protective part due to being too thick, and the material accumulation and production cost can also be reduced.

[0122] In some embodiments, the insulating base body includes a first insulating base part and a second insulating base part, the conductive main body part is covered on the first insulating base part, and the conductive part is covered on the second insulating base part; the thickness of the conductive main body part 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 part is t8, and the thickness of the second insulating base part is t9, wherein -4μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4μm, and optionally, -2μm≤(t1+t6+t8 / 2)-(t2+t7+t8 / 2)≤2μm.

[0123] By adopting the technical scheme of the embodiment, the design of -4 μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4 μm makes the half thickness of the current collector at the conductive main body part close to the half thickness of the current collector at the conductive part, which is beneficial to the surface of the metal layer away from the conductive protective layer being close to a plane, reducing the roll damage and improving the flow capacity of the metal layer; in addition, the drum edge of the electrode assembly can also be reduced.

[0124] In some embodiments, the thickness of the second insulating base is less than the thickness of the first insulating base.

[0125] By adopting the technical scheme of the embodiment, the thickness of the second insulating base is less than the thickness of the first insulating base, so that the sum of the thicknesses of the second insulating base and the conductive part is close to the sum of the thicknesses of the first insulating base and the conductive main body part, which is beneficial to the surface of the metal layer away from the insulating base being close to a plane, reducing the roll damage and improving the flow capacity of the metal layer.

[0126] In some embodiments, the shell comprises a shell body and an end cover, the end cover is arranged at the opening of the shell body, the shell body and the end cover surround to form a containing cavity, the electrode assembly is contained in the containing cavity, and at least one of the shell body and the end cover is provided with an electrode lead-out part.

[0127] By adopting the technical scheme of the embodiment, the shell adopts the structure of the end cover and the shell body, the electrode assembly is easy to be loaded into the shell, the assembly of the battery monomer is facilitated, and the manufacturing cost is reduced.

[0128] In some embodiments, the capacity of the battery monomer is greater than or equal to 20 A·h.

[0129] By adopting the technical scheme of the embodiment, the metal layer adopts the thickened structure form of the conductive part, which can better meet the use requirement that the capacity of the battery monomer is greater than or equal to 20 A·h.

[0130] In some embodiments, the first pole piece is a positive pole piece, and the active material of the active material layer contains a Ni element.

[0131] By adopting the technical scheme of the embodiment, the active material of the active material layer contains a Ni element, which can improve the energy density of the battery monomer, in addition, the positive pole piece adopts the structure form of the first pole piece, and the current collector of the first pole piece adopts the structure form of the composite current collector, which can reduce the risk of internal short circuit of the battery monomer and reduce the risk of thermal runaway of the battery monomer.

[0132] In some embodiments, the material of the metal layer comprises one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0133] By adopting the technical scheme of the embodiment, the metal layer adopts the above material, which is beneficial to improve the performance of the battery monomer.

[0134] In a second aspect, a battery device is provided, which includes the battery monomer of the above embodiment.

[0135] The battery device of the embodiment of the application adopts the above battery monomer, and the fast charging performance and use reliability of the battery monomer are good, which is beneficial to improve the fast charging performance and use reliability of the battery device and also beneficial to improve the use reliability of the battery device.

[0136] In a third aspect, a power consumption device is provided, which includes the battery device of the above embodiment.

[0137] The power consumption device of the embodiment of the application adopts the above battery device, and the fast charging performance and use reliability of the battery device are good, which is beneficial to improve the endurance of the power consumption device and also beneficial to improve the use reliability of the power consumption device.

[0138] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, the specific embodiments of the application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following will describe the specific embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0139] In order to more clearly illustrate the technical scheme in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0140] Fig. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the application.

[0141] Fig. 2 is an exploded schematic diagram of a battery device provided by some embodiments of the application.

[0142] Fig. 3 is an exploded schematic diagram of a battery monomer provided by some embodiments of the application.

[0143] Fig. 4 is a structural schematic diagram of an electrode assembly provided by some embodiments of the application.

[0144] Fig. 5 is a sectional view along line A-A in Fig. 4.

[0145] Fig. 6 is a structural schematic diagram of a first pole piece provided by some embodiments of the application.

[0146] Fig. 7 is a sectional view along line B-B in Fig. 6.

[0147] Fig. 8 is an enlarged view of a portion of Fig. 6 at C.

[0148] Fig. 9 is a schematic view of a structure of a first pole piece after hiding a conductive member according to some embodiments of the present application.

[0149] Fig. 10 is an enlarged view of a portion of Fig. 9 at D.

[0150] Fig. 11 is a schematic view of a structure of a first pole piece according to other embodiments of the present application.

[0151] Fig. 12 is an enlarged view of a portion of Fig. 11 at E.

[0152] Fig. 13 is a schematic view of a structure of a first pole piece after hiding a conductive member according to some embodiments of the present application.

[0153] Fig. 14 is an enlarged view of a portion of Fig. 13 at F.

[0154] Fig. 15 is a schematic view of a structure of a first pole piece according to further embodiments of the present application.

[0155] Fig. 16 is a sectional view along line H-H of Fig. 15.

[0156] Fig. 17 is a sectional view along line I-I of Fig. 15.

[0157] Fig. 18 is a schematic view of a structure of a first pole piece according to further embodiments of the present application.

[0158] Fig. 19 is an enlarged view of a portion of Fig. 18 at J.

[0159] Fig. 20 is a schematic view of a structure of a first pole piece according to further embodiments of the present application.

[0160] Fig. 21 is a sectional view along line K-K of Fig. 20.

[0161] Fig. 22 is a schematic view of a structure of a second insulating portion according to some embodiments of the present application.

[0162] Fig. 23 is a sectional view along line N-N of Fig. 22.

[0163] In the drawings, reference numerals: 1000, vehicle; 1100, battery device; 1200, controller; 1300, motor; 100, battery cell; 101, electrode assembly; 1, first tab; 10, current collector; 11, insulating base body; 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, protruding portion; 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 connecting portion; 311, first connecting sub-portion; 312, second connecting sub-portion; 32, second connecting portion; 40, insulating member; 41, first insulating portion; 42, second insulating portion; 421, first portion; 422, second portion; 423, insulating base layer; 424, adhesive layer; 51, first solder print; 511, first solder print portion; 5111, first solder print sub-portion; 5112, second solder print sub-portion; 512, second solder print portion; 52, second solder print; 60, conductive protective layer; 61, first protective portion; 62, second protective portion; 621, second main body segment; 622, second transition segment; 2, second tab; 210, main body functional portion; 220, tab portion; 3, spacer; 200, housing; 201, end cap; 202, case; 2011, electrode lead-out portion; 300, box; 301, first box portion; 302, second box portion. DETAILED DESCRIPTION

[0164] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings 1-23 and examples. It should be understood that the specific examples described herein are only intended to explain the present application and are not intended to limit the present application.

[0165] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "include" and "have" and any variations thereof used in the specification and claims of this application and the above description of drawings are intended to cover the inclusion not the exclusion of one or more elements.

[0166] In the description of the embodiments of the present application, the technical terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0167] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after it.

[0168] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces). The meaning of "several" is one or more, unless otherwise explicitly specified.

[0169] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0170] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0171] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element with intervening elements present. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element with intervening elements present.

[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, a lithium ion battery cell, a sodium ion battery cell, a sodium lithium ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium sulfur battery cell, a magnesium ion battery cell, a nickel hydrogen battery cell, a nickel cadmium battery cell, a lead-acid battery cell, 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, and the prismatic battery cell includes a square cell, a blade cell, a multi-prismatic battery cell, such as a hexagonal prismatic battery cell, etc.

[0175] The battery device referred to 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, and when there are a plurality of battery cells, the plurality of battery cells are arranged and fixed to form a battery module.

[0177] In some embodiments, the battery device can be a battery pack, and the battery pack includes a box and a battery cell, and the battery cell or the battery module is accommodated in the box.

[0178] In some embodiments, the box can be part of the chassis structure of the vehicle. For example, part of the box can be at least part of the floor of the vehicle, or part of the box can be at least part of the cross beam and the 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 case, and the electrode assembly is accommodated in the case. The electrode assembly includes a positive electrode and a negative electrode. During the charging and discharging of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode.

[0181] In some embodiments, the electrode assembly further comprises a separator disposed between the positive electrode and the negative electrode, which can prevent the positive electrode and the negative electrode from short circuiting while allowing active ions to pass through.

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

[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 metal materials, such as metal aluminum foil and metal copper foil. However, pure metal foil material is prone to metal burrs, and the burrs can penetrate the separator to cause internal short circuit, resulting in a high risk of fire and explosion of the battery cell.

[0185] In order to reduce the risk of short circuit in the battery cell, a current collector is provided, which includes an insulating base and a metal layer covering the surface of the insulating base, and an active material layer covering the surface of the metal layer away from the insulating base. The thickness of the metal layer is usually small (for example: between a few hundred nanometers and a few microns), so that the burr generated by the metal layer during the penetration of foreign matter into the electrode sheet is small and is not easy to penetrate the separator. The metal layer is connected to the electrode lead-out part on the shell for output or input of the electrical energy of the battery cell. However, the thickness of the metal layer is small, and the cross-sectional area of the connection part between the metal layer and the electrode lead-out part is small, resulting in poor overcurrent capacity of the connection part between the metal layer and the electrode lead-out part, which is not conducive to the improvement of the fast charging performance of the battery cell.

[0186] Based on this, the embodiments of the present application provide a technical scheme, which designs the metal layer into a structure with inconsistent thickness, i.e. the thickness of the conductive part connected to the electrode lead-out part is greater than the thickness of the conductive main part. By increasing the thickness of the conductive part, the overcurrent area of the conductive part is increased, the overcurrent capacity of the conductive part is improved, the overcurrent capacity of the metal layer is improved, the heat generation of the battery cell is reduced, the charging and discharging efficiency of the battery cell is improved, and the fast charging performance of the battery cell is improved.

[0187] The electrode assembly described in the embodiments of the present application is suitable for battery cells, battery devices, and electric devices using the battery devices.

[0188] The battery device disclosed by the embodiments of the present application can be used in a power consumption device using the battery device as a power source or a variety of energy storage systems using the battery device as an energy storage element. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, and an electric aircraft toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0189] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0190] As shown in FIG. 1, the vehicle 1000 is internally provided with a battery device 1100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery device 1100 can be used for power supply of the vehicle 1000, for example, the battery device 1100 can be used as an operating power source of the vehicle 1000.

[0191] The vehicle 1000 can further include a controller 1200 and a motor 1300, and the controller 1200 is used to control the battery device 1100 to supply power to the motor 1300, for example, to meet the power demand of the vehicle 1000 during starting, navigation and driving.

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

[0193] As shown in FIG. 2, the battery device 1100 includes a box body 300 and a battery cell 100, and the battery cell 100 is accommodated in the box body 300.

[0194] The box 300 is used to accommodate the battery cell 100, and the box 300 can be of various structures. In some embodiments, the box 300 can include a first box part 301 and a second box part 302, the first box part 301 and the second box part 302 are mutually covered, and the first box part 301 and the second box part 302 jointly define an accommodation space for accommodating the battery cell 100. The second box part 302 can be a hollow structure with one end open, and the first box part 301 is a plate-like structure, which covers the open side of the second box part 302 to form the box 300 with the accommodation space; the first box part 301 and the second box part 302 can also be hollow structures with one side open, and the open side of the first box part 301 covers the open side of the second box part 302 to form the box 300 with the accommodation space. Of course, the first box part 301 and the second box part 302 can be of various shapes, such as a cylinder, a cuboid, etc.

[0195] To improve the sealing performance of the first box part 301 and the second box part 302 after being connected, a sealing member such as sealing glue, a sealing ring, etc. can be arranged between the first box part 301 and the second box part 302.

[0196] Suppose the first box part 301 covers the top of the second box part 302, the first box part 301 can also be called an upper box cover, and the second box part 302 can also be called a lower box.

[0197] In the battery device 1100, the battery cell 100 can be one or multiple. If the battery cell 100 is multiple, the multiple battery cells 100 can be connected in series, in parallel, or in a mixed manner, and the mixed manner means that the multiple battery cells 100 are connected in series and in parallel.

[0198] The multiple battery cells 100 can be directly connected in series, in parallel, or in a mixed manner, and then the whole of the multiple battery cells 100 is accommodated in the box 300; of course, the multiple battery cells 100 can first be connected in series, in parallel, or in a mixed manner to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole, which is accommodated in the box 300.

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

[0200] As shown in FIG. 3, 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 (for example, lithium ions) are embedded and extracted between the positive electrode and the negative electrode. Optionally, the electrode assembly 101 further includes a separator 3 arranged between the positive electrode and the negative electrode, which can reduce the risk of short circuit of the positive electrode and the negative electrode, and at the same time allow the active ions to pass through.

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

[0202] In some embodiments, the shell 200 includes a casing 202 having an opening and an end cap 201 used to cover the opening.

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

[0204] The casing 202 and the end cap 201 can be independent components. For example, the casing 202 can be provided with an opening, and the end cap 201 is used to cover the opening to form the internal cavity of the battery cell 100.

[0205] The casing 202 can be in various shapes and sizes, such as cuboid, cylinder, hexagonal prism, etc. Specifically, the shape of the casing 202 can be determined according to the specific shape and size of the electrode assembly 101. The material of the casing 202 can be various, such as 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 casing 202 to cooperate with the casing 202. The material of the end cap 201 can be the same as or different from that of the casing 202. Optionally, the end cap 201 can be made of a material with certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 201 is not easy to deform when subjected to extrusion and collision, so that the battery cell 100 can have higher structural strength and reliability.

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

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

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

[0210] In some embodiments, the battery cell 100 also includes an electrolyte housed within the housing 200. The electrolyte serves to conduct ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid.

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

[0212] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, 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 can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl 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, butyrosulfone, 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, methyl tetrahydrofuran, diphenyl ether, and crown ether.

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

[0216] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, 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 one or more of oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfur, argyrodite), amorphous sulfide), halide solid electrolyte, nitride solid electrolyte, and hydride solid electrolyte.

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

[0220] Referring to FIGS. 4 and 5, the electrode assembly 101 of the embodiment of the present application includes first and second polar pieces 1 and 2 having opposite polarities.

[0221] Illustratively, one of the first and second polar pieces 1 and 2 is a positive polar piece, and the other is a negative polar piece.

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

[0223] As an example, the positive current collector has two surfaces opposite in the thickness direction thereof, and the positive active material layer is disposed on either one or both of the two opposite surfaces of the positive current collector.

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

[0225] As an example, the positive active material layer includes a positive active material, and the positive active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. The positive active material can also use other conventional materials that can be used as the positive active material layer of the battery device 1100. These positive active materials can be used only one kind alone, or two or more kinds in combination. Examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (which can also be referred to simply as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to simply as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to simply as NCM523), LiNi0.5 Co 0.25 Mn 0.25 O2(also can be referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM811), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.80 Co 0.15 AL 0.05 O2), and modified compounds thereof.

[0226] In some embodiments, the negative electrode tab 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.

[0227] As an example, the negative electrode current collector can employ a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, nickel, or titanium, etc. can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a 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 (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (e.g., a base material 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 employ a negative electrode active material known in the art for use in the battery cell 100. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can include at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can include at least one of elemental tin, a tin oxide compound, and a tin alloy. The negative electrode active material of the present application can also use other conventional materials that can be used as a negative electrode active material for the battery device 1100. These negative electrode active materials can be used alone only one or two or more can be used in combination.

[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 comprises a separator 3 for separating 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 while allowing the active ions to pass through.

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

[0232] For example, the main material of the separator film can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film. When the separator film is a multi-layer composite film, the materials of the layers 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 surface of the positive and negative electrodes.

[0233] In some embodiments, the separator 3 is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode sheet and the negative electrode sheet and functions to transport ions and separate the positive and negative electrodes.

[0234] In some embodiments, the electrode assembly 101 has a wound structure. For example, the first electrode sheet 1 and the second electrode sheet 2 each have a strip shape, and the first electrode sheet 1, the separator 3, and the second electrode sheet 2 are wound to form the wound structure.

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

[0236] For example, a plurality of first electrode sheets 1 and a plurality of second electrode sheets 2 can be alternately stacked.

[0237] For example, a plurality of first electrode sheets 1 can be provided, and the second electrode sheet 2 can be folded to form a plurality of folded segments that are stacked.

[0238] For example, a plurality of first electrode sheets 1 and a plurality of second electrode sheets 2 can be alternately stacked.

[0239] For example, a plurality of separators 3 can be provided between any adjacent first electrode sheets 1 or second electrode sheets 2.

[0240] For example, a plurality of separators 3 can be provided between any adjacent first electrode sheets 1 or second electrode sheets 2.

[0241] In some embodiments, the electrode assembly 101 can have a cylindrical shape, a flat shape, or a polygonal shape.

[0242] Please refer to Figs. 6-10, in some embodiments, a battery cell 100 is provided, the battery cell 100 comprises a housing 200 and an electrode assembly 101, the housing 200 is provided with an electrode lead-out portion 2011; at least part of the electrode assembly 101 is arranged in the housing 200; the electrode assembly 101 comprises a first electrode tab 1, the first electrode tab 1 comprises a current collector 10 and an active material layer 20, the current collector 10 comprises an insulating base 11 and a metal layer 12, the insulating base 11, the metal layer 12 and the active material layer 20 are stacked along the thickness direction of the current collector 10, at least part of the metal layer 12 is located between the insulating base 11 and the active material layer 20; wherein the metal layer 12 comprises 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 part of the conductive main body portion 13 is covered with the active material layer 20, at least part of the conductive portion 14 is not covered with the active material layer 20, the conductive portion 14 is connected with 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] Part of the electrode assembly 101 is located in the housing 200; another part is located outside the housing 200, or the entire electrode assembly 101 is located in 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 comprises the metal layer 12 and the insulating base 11, the current collector 10 is a multi-layer structure, the insulating base 11 can refer to a component in the current collector 10 made of an insulating material (for example: the above-mentioned high molecular base material), and the metal layer 12 can refer to a component in the current collector 10 made of the above-mentioned metal material.

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

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

[0248] In some examples, both surfaces of the insulating base 11 are covered with the metal layer 12, and at least one of the two metal layers 12 is covered with the active material layer 20 on the surface facing away from the insulating base.

[0249] The first direction can refer to a direction perpendicular to the thickness direction of the current collector 10; and the second direction can 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 in a wound structure, and when the first tab 1 is in an unfolded state, the first direction can refer to the width direction of the first tab 1 (see the Z direction in FIG. 6); and the second direction can refer to the length direction of the first tab 1 (see the X direction in FIG. 6). When the first tab 1 is in a wound state, the second direction can also refer to the winding direction of the first tab 1 (see the direction indicated by the arrow V in FIG. 4).

[0251] In some examples, the electrode assembly 101 is in a stacked structure, and the first direction can refer to the width direction of the first tab 1 (see the Z direction in FIG. 6); and the second direction can refer to the length direction of the first tab 1 (see the X direction in FIG. 6).

[0252] In some examples, along the first direction, the metal layer 12 is divided into two parts, one of which is the conductive main body part 13, and the other of which is the conductive part 14. The conductive part 14 is formed from the extension of the conductive main body part 13 along the first direction. A part of the conductive main body part 13 is covered with the active material layer 20, another part of the conductive main body part 13 is not covered with the active material layer 20, or the entire region of the conductive main body part 13 is covered with the active material layer 20. A part of the conductive part 14 is not covered with the active material layer 20, another part of the conductive part 14 is covered with the active material layer 20, or the entire region 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 part for outputting or inputting electric energy. The electrode lead-out part 2011 is connected to an external electronic device to enable the battery monomer 100 to output or input electric energy. The electrode lead-out part 2011 can also be referred to as a pole. The electrode lead-out part 2011 can be provided on the housing 202 or on the end cover 201.

[0254] The electrode lead-out portion 2011 is connected with the conductive portion 14, and the electrode lead-out portion 2011 can be directly connected with the conductive portion 14; for example, the electrode lead-out portion 2011 is directly welded on the conductive portion 14; or the electrode lead-out portion 2011 can be connected with the conductive portion 14 through a conductive component (for example, a conductive member 30, etc.), for example, a first end of the conductive component is welded with the electrode lead-out portion 2011, and a second end of the conductive component is welded with the conductive portion 14; wherein the second end of the conductive component can be directly welded with the conductive portion 14, or can be welded through a conductive piece (for example, a adapter sheet, etc.).

[0255] In the case of normal use of the battery monomer 100, the electrode lead-out portion 2011 is used for input or output of electric energy, realizing charging and discharging of the battery monomer 100; and the thickness of the conductive portion 14 connected with the electrode lead-out portion 2011 is greater than the thickness of the conductive main portion 13, which improves the overcurrent area of the conductive portion 14, improves the overcurrent capacity of the conductive portion 14, reduces the heat generation of the battery monomer 100, is conducive to improving the charging and discharging efficiency of the battery monomer 100, and improving the fast charging performance of the battery monomer 100; in addition, the current collector 10 adopts the composite structure of the insulating base body 11 and the metal layer 12, and the thickness of the metal layer 12 is smaller than that of the pure metal current collector 10, the burr generated in the manufacturing process of the current collector 10 is smaller, the risk of internal short circuit of the battery monomer 100 is reduced, and the use reliability of the battery monomer 100 is improved; therefore, the battery monomer 100 of 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 base body 11 is further away from the insulating base body 11 than the surface of the conductive main portion 13 facing away from the insulating base body 11.

[0257] In the direction of the insulating base body 11 towards the metal layer 12, the surface of the conductive portion 14 facing away from the insulating base body 11 can protrude the surface of the conductive main portion 13 facing away from the insulating base body 11.

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

[0259] In some examples, the surface of the conductive portion 14 facing towards the insulating base body 11 can be flush with the surface of the conductive main portion 13 facing towards the insulating base body 11, and the insulating base body 11 can adopt an equal thickness structure, which has good structural strength, improves the structural strength of the current collector 10, and improves the use reliability of the battery monomer 100.

[0260] By adopting the technical scheme of the embodiment, the surface of the conductive part 14 away from the insulating base 11 protrudes away from the insulating base 11 relative to the conductive main part 13, the space of the side of the conductive part 14 away from the insulating base 11 can be utilized, the risk of thinning the insulating base 11 at the conductive part 14 to accommodate the conductive part 14 can be reduced, the structural strength of the insulating base 11 at the conductive part 14 can be improved, the structural strength of the current collector 10 can be improved, and the use reliability of the battery monomer 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 the first direction, the first conductive part 141 is connected between the second conductive part 142 and the conductive main part 13, the first conductive part 141 is covered with the 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 with the electrode lead-out part 2011.

[0262] The first conductive part 141 can be a part of the conductive part 14 covered with the active material layer 20; the second conductive part 142 can be a 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 divided by the end surface of the active material layer 20; the thickness of the first conductive part 141 and the thickness of the second conductive part 142 are both greater than the thickness of the conductive main part 13.

[0263] For example, the conductive part 14 can be divided into two parts along the first direction, wherein the part close to the conductive main part 13 and covered with the active material layer 20 is the first conductive part 141, and the part away from the conductive main 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 with the electrode lead-out part 2011, on the one hand, the connection of the electrode lead-out part 2011 and the metal layer 12 can be facilitated, and on the other hand, the risk of the electrode lead-out part 2011 contacting the active material layer 20 can be reduced, the mutual influence between the two can be reduced, and the use reliability of the battery monomer 100 can be improved.

[0265] By adopting the technical scheme of the embodiment, the active material layer 20 covers the first conductive part 141, which is conducive to improving the electron transmission capability 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 improving the fast charging performance of the battery monomer 100. In addition, the conductive main part 13 and the first conductive part 141 are also covered with the active material layer 20, which is conducive to improving the electron transmission capability of the first pole piece 1 at the junction of the first conductive part 141 and the conductive main part 13, reducing the resistance of the first pole piece 1, and improving the fast charging performance of the battery monomer 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 a first direction, the first active material part 21 is connected with 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 part 13.

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

[0267] The first active material part 21 is located at the edge of the active material layer 20 to cover the first conductive part 141, wherein the first active material part 21 can cover part of the first conductive part 141, the other part of the first active material part 21 and the entire second active material part 22 cover the conductive main part 13, or the entire first active material part 21 covers the first conductive part 141, and the entire second active material part 22 covers the conductive main part 13, or the entire first active material part 21 covers part of the first conductive part 141, part of the second active material part 22 covers another part of the first conductive part 141, and another part of the second active material part 22 covers the conductive main part 13.

[0268] In some examples, the first active material portion 21 can be substantially an equal-thickness structure, the thickness of the first active material portion 21 being smaller than the thickness of the second active material portion 22, so that the first active material portion 21 and the second active material portion 22 form a stepped structure; in other examples, the thickness of the first active material portion 21 can also be steppedly reduced, so that the first active material portion 21 is a stepped structure; or, the thickness of the first active material portion 21 can also be slowly reduced in the direction of the conductive body portion 13 towards the conductive portion 14, so that the thickness of the first active material portion 21 is slowly reduced, and the first active material portion 21 has a more rounded or smooth shape.

[0269] By adopting the technical solutions of this embodiment, in the forming process of the first pole piece 1, the active material layer 20 can be rolled to compact the active material layer 20; the first active material portion 21 can reduce the rolling pressure on the edge of the active material layer 20 and reduce the risk of cracking of 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, the thickness of the first conductive portion 141 is greater than the thickness of the conductive body portion 13, and the first active material portion 21 covers this part, which is conducive to reducing the overall thickness of the first pole piece 1 at the first active material portion 21 and reducing the pressure on the edge of the active material layer 20, and further reducing the risk of cracking of the edge of the active material layer 20.

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

[0271] It can be understood that, in the direction of the insulating base 11 towards the metal layer 12, the conductive body portion 13 protrudes from the first active material portion 21, so that the thickness of the first pole piece 1 at the first active material portion 21 is smaller than the thickness of the first pole piece 1 at the conductive body portion 13.

[0272] By adopting the technical solutions of this embodiment, the rolling pressure on the first active material portion 21 can be reduced, which is conducive to reducing the risk of cracking of the active material layer 20.

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

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

[0275] By adopting the technical scheme of the embodiment, the second active material part 22 covers the first conductive part 141, the first conductive part 141 is covered with more active materials, the electronic transmission capacity 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 capability of the battery monomer 100.

[0276] In some embodiments, along the first direction, the size of the part of the first conductive part 141 covered by the second active material part 22 is W1, and the size of the part of the first conductive part 141 covered by the first active material part 21 is W2, W1≥W2.

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

[0278] For example, the size W1 of the part of the first conductive part 141 covered by the second active material part 22 can refer to the width of the part of the first conductive part 141 covered by the second active material part 22. The size W2 of the part of the first conductive part 141 covered by the first active material part 21 can refer to the width of the part of the first conductive part 141 covered by the first active material part 21.

[0279] By adopting the technical scheme of the embodiment, the larger part of the first conductive part 141 is covered by the second active material part 22, and the 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 with more active materials, the electronic transmission capacity 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 capability of the battery monomer 100.

[0280] In some embodiments, the thickness of the conductive main part 13 is t1, the maximum thickness of the first conductive part 141 is t2, and the thickness of the second active material part 22 is t3, wherein 0.002≤(t2-t1) / t3≤0.08.

[0281] The second conductive part 142 is substantially an equal-thickness structure, the thickness of the second conductive part 142 is equal to the maximum thickness t2 of the first conductive part 141, and the thickness of the second conductive part 142 can be the maximum thickness t4 of the conductive part 14; in some examples, the first conductive part 141 is substantially 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, the maximum thickness of the first conductive part 141 is equal to the thickness of the segment with the maximum thickness, for example, the first conductive part 141 includes two segments, and the thickness of the first segment gradually increases in the direction from the conductive main body part 13 to the conductive part 14, and the second segment is substantially 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 thickness of the first segment gradually increases from the thickness of the conductive main body part 13 to the thickness of the second segment, and such an arrangement facilitates smooth transition of the first segment to the second segment and the conductive main body part 13, thereby reducing stress concentration and improving structural strength.

[0282] t2-t1 can refer to the thickness difference between the first conductive part 141 and the conductive main body part 13.

[0283] The value of (t2-t1) / t3 can be 0.002, 0.08, or any value within the range of 0.002-0.08; for example, the value of (t2-t1) / t3 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, or 0.08.

[0284] In some examples, the arrangement of 0.002≤(t2-t1) / t3≤0.08 makes the thickness difference between the first conductive part 141 and the conductive main body part 13 within the thickness error range of the active material layer 20, so that the thickening of the first conductive part 141 is less likely to cause the surface of the active material layer 20 to protrude, thereby improving the flatness of the surface of the active material layer 20 away from the insulating substrate 11, facilitating the manufacturability of the first pole piece 1, and reducing subsequent roll damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, thereby improving the use 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 away from the insulating substrate 11, and facilitating the manufacturability of the first pole piece 1.

[0286] In some embodiments, 0.003≤(t2-t1) / t3≤0.06.

[0287] By adopting the technical scheme of the embodiment, the thickness difference between the first conductive part 141 and the conductive main part 13 and the thickness of the second active material part 22 are in a more reasonable range, the flatness of the surface of the active material layer 20 away from the insulating base body 11 is improved, and the manufacturability of the first electrode sheet 1 is improved.

[0288] In some embodiments, 60 μm≤t3≤250 μm.

[0289] It can be understood that the value of t3 can be 60 μm, 250 μm, and any value between 60 μm and 250 μm; for example, the value of t3 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] The design of t3≥60 μm makes the battery monomer 100 have a higher capacity; the design of t3≤250 μm makes the distance of electron extraction in the part of the active material layer 20 close to the metal layer 12 not too long, which is beneficial to the extraction of electrons and improves the capacity of the battery monomer 100.

[0291] By adopting the technical scheme of the embodiment, the thickness of the second active material part 22 is in a suitable range, the volume of the active material layer 20 is reasonably set, which is beneficial to improve the fast charging performance and use reliability of the battery monomer 100, and can also reduce the risk of ion extraction difficulty in the area of the active material layer 20 close to the conductive layer, and the performance of the battery monomer 100 is improved.

[0292] In some embodiments, 80 μm≤t3≤180 μm.

[0293] By adopting the technical scheme of the embodiment, the thickness of the second active material part 22 is in a suitable range, the volume of the active material layer 20 is reasonably set, which is beneficial to improve the fast charging performance and use reliability of the battery monomer 100, and can also reduce the risk of ion extraction difficulty in the area of the active material layer 20 close to the conductive layer, and the performance of the battery monomer 100 is improved.

[0294] In some embodiments, along the first direction, the size of the first conductive part 141 is W3, and the size of the conductive part 14 is W4, wherein W3 / W4≤0.4.

[0295] For example, the size W3 of the first conductive part 141 can refer to the width of the first conductive part 141, and W3=W1+W2; the size W4 of the conductive part 14 can refer to the width of the conductive part 14, and W4=W3+W7, where W7 can refer to the size of the second conductive part 142 along the first direction, i.e., the width of the second conductive part 142.

[0296] W3 / W4≤0.4, and it can be understood that the value of W3 / W4 can be 0.4 and any value between 0 and 0.4; for example, the value of W3 / W4 can be, but is not limited to, 0.001, 0.1, 0.2, 0.3, 0.4.

[0297] By adopting the technical scheme of this embodiment, the design of W3 / W4≤0.4 makes the ratio of the size of the first conductive part 141 to the size of the conductive part 14 along the first direction reasonable, facilitates the connection of the second conductive part 142 and the electrode lead-out part 2011, and has better electron transmission capability between the first conductive part 141 and the active material layer 20, which is conducive to reducing the resistance of the first electrode tab 1 and improving the fast charging performance of the battery monomer 100.

[0298] In some embodiments, along the first direction, the size of the first conductive part 141 is W3, and the size of the conductive part 14 is W4, where 2mm≤W4-W3≤10mm.

[0299] W4-W3 can refer to the size of the second conductive part 142 along the first direction, i.e., the width of the second conductive part 142, i.e., W7.

[0300] 2mm≤W4-W3≤10mm, and it can be understood that the value of W4-W3 can be 2mm, 10mm and any value between 2mm and 10mm; for example, the value of W4-W3 can be, but is not limited to, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm.

[0301] By adopting the technical scheme of this embodiment, the design of 2mm≤W4-W3≤10mm makes the size of the second conductive part 142 along the first direction within a reasonable range, which facilitates the connection of the second conductive part 142 and the electrode lead-out part 2011, and also reduces the occupation of too much space due to the too large size of the second conductive part 142 along the first direction, which is conducive to improving the energy density of the battery monomer 100.

[0302] In some embodiments, 3mm≤W4-W3≤6mm.

[0303] By adopting the technical solutions of the embodiment, the design of 2mm≤W4-W3≤10mm makes the size of the second conductive part 142 in the first direction be within a more reasonable range, facilitates the connection of the second conductive part 142 with the electrode lead-out part 2011, and can also reduce the occupation of too much space due to the too large size of the second conductive part 142 in the first direction, which is beneficial to improving the energy density of the battery monomer 100.

[0304] In some embodiments, the size of the first conductive part 141 in the first direction is W3, and the size of the conductive main body part 13 is W5, where W3 / (W3+W5)≤0.45.

[0305] For example, the size W5 of the conductive main body part 13 can be the width of the conductive main body part 13. W3+W5 can refer to the width of the part of the metal layer 12 covered with the active material layer 20.

[0306] W3 / (W3+W5) can refer to the proportion 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] W3 / (W3+W5)≤0.45 can be understood as that the value of W3 / (W3+W5) can be 0.45 and any value between 0 and 0.45; for example, the value of W3 / (W3+W5) can be but is not limited to 0.001, 0.1, 0.2, 0.3, 0.4, 0.45.

[0308] By adopting the technical solutions of the embodiment, the design of W3 / (W3+W5)≤0.45 makes the ratio of the size of the first conductive part 141 in the first direction to the sum of the size of the first conductive part 141 and the size of the conductive main body part 13 be within a suitable range, the first conductive part 141 can cover the active material layer 20, which is beneficial to reducing the internal resistance of the first pole piece 1 and improving the fast-charging capability of the battery monomer 100; in addition, the size of the first conductive part 141 in the second direction 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 monomer 100.

[0309] In some embodiments, the size of the first conductive part 141 in the first direction is W3, where 10mm≤W3≤100mm.

[0310] It can be understood that the value of W3 can be 10mm, 100mm and any value between 10mm and 100mm; for example, the value of W3 can be but is not limited to 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm.

[0311] By adopting the technical scheme of the embodiment, the design of 10mm≤W3≤100mm makes the size of the first conductive part 141 in the first direction be within a reasonable range, so that the active material layer 20 and the first conductive part 141 have good electron transmission capability, in addition, in the second direction, the size of the first conductive part 141 is not too large, which is beneficial to reduce the space and weight occupied by the first conductive part 141, and is beneficial to improve the energy density of the battery monomer 100.

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

[0313] The protruding part 1421 can refer to a protruding structure of the edge of the metal layer 12, and in the second direction, the size l1 of the protruding part 1421 is smaller than the size L1 of the conductive main part 13. The number of protruding parts 1421 can be one or more. The thickness of the protruding part 1421 is greater than the thickness of the conductive main part 13; the number of protruding parts 1421 can be one or more, and the plurality of protruding parts 1421 are arranged at intervals in the second direction.

[0314] In some examples, the protruding part 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 part connecting the first conductive part 141 and the protruding part 1421.

[0315] By adopting the technical scheme of the embodiment, in the second direction, the size l1 of the protruding part 1421 is smaller than the size L1 of the conductive main part 13, the protruding part 1421 is easy to be connected with the electrode lead-out part 2011 by bending the conductive member 30, which is convenient for processing and manufacturing, and is also beneficial to reduce the space occupied by the conductive member 30 after being bent, and is beneficial to improve the energy density of the battery monomer 100.

[0316] In some embodiments, 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 first conductive part 141, and the first protruding sub-part 14211 is connected with the electrode lead-out part 2011; in the second direction, the size of the first protruding sub-part 14211 is greater than the size of the second protruding sub-part 14212.

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

[0318] In the second direction, the size l2 of the first protruding sub-portion 14211 is greater than the size l3 of the second protruding sub-portion 14212, that is, the protruding portion 1421 has a stepped structure in the second direction, wherein the first protruding sub-portion 14211 has a greater size, the second protruding sub-portion 14212 has a smaller size, and the plurality of protruding portions 1421 are arranged at intervals in the second direction, so that the sum of the sizes l1 of the first protruding sub-portion 14211 of the plurality of protruding portions 1421 is less than the size L1 of the conductive main body portion 13.

[0319] By adopting the technical solutions of this embodiment, in the second direction, the first protruding sub-portion 14211 is large, the first protruding sub-portion 14211 has a large flow area and a strong flow capacity, which is conducive to reducing heat generation and improving the fast-charging performance and use reliability of the battery monomer 100.

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

[0321] In some examples, the first protruding sub-portion 14211 and the second protruding sub-portion 14212 are both connected to the electrode lead-out portion 2011, so that the 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, and the current can directly flow through the first protruding sub-portion 14211 and the second protruding sub-portion 14212, which have a large flow area and a good flow capacity, are conducive to reducing heat generation, and are conducive to improving the fast-charging performance and use reliability of the battery monomer 100.

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

[0323] In some embodiments, the number of protruding portions 1421 is a plurality, and the plurality of protruding portions 1421 are arranged at intervals in the second direction, and in the second direction, the sum of the sizes l1 of all the protruding portions 1421 is less than the size L1 of the conductive main body portion 13.

[0324] The plurality of protruding portions 1421 are arranged at intervals in the length direction of the first pole piece 1, and after being wound, the plurality of protruding portions 1421 are arranged in layers to form an integral bending portion connected to the electrode lead-out portion 2011; in addition, the gap between the adjacent two protruding portions 1421 also makes the sum of the sizes l1 of the plurality of protruding portions 1421 in the second direction less than the size L1 of the conductive main body portion 13; wherein the plurality of protruding portions 1421 can adopt the same structure or different structures.

[0325] By adopting the technical solutions of this embodiment, the plurality of protruding portions 1421 are arranged at intervals along the second direction, which is conducive to dividing the conductive main body portion 13 into a plurality of regions along the second direction, and one region can correspond to one protruding portion 1421, and 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 a region-by-region manner, and the transmission path of the electrons in each region is transmitted to the corresponding protruding portion 1421, which is short, thereby reducing the transmission distance of the electrons, reducing the overall resistance of the first electrode sheet 1, and improving the fast charging performance and use reliability of the battery monomer 100.

[0326] In some embodiments, the second conductive portion 142 further includes a transition portion 1422, which is connected between the protruding portion 1421 and the first conductive portion 141, and along the second direction, the size L2 of the transition portion 1422 is greater than the sum of the sizes l1 of all the protruding portions 1421.

[0327] The transition portion 1422 can 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, so that along the second direction, the size L2 of the transition portion 1422 is greater than the sum of the sizes l1 of all the protruding portions 1421, or along the second direction, the size L2 of the transition portion 1422 is equal to the size l1 of the protruding portion 1421.

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

[0329] By adopting the technical solutions of this embodiment, the thickness of the transition portion 1422 is greater than the thickness of the conductive main body portion 13, and the size L2 of the transition portion 1422 along the second direction is large, and the current-carrying capacity of the transition portion 1422 is strong, which is conducive to reducing heat generation and improving the fast charging performance and use reliability of the battery monomer 100.

[0330] In some embodiments, along the second direction, the size of the conductive main body portion 13 is L1, and the size of the transition portion 1422 is L2, and 0.8≤L2 / L1≤1.

[0331] 0.8≤L2 / L1≤1, along the second direction, the size L2 of the transition portion 1422 is less than or equal to the size L1 of the conductive main body portion 13, and the size L2 of the transition portion 1422 is greater than or equal to 0.8 times the size L1 of the conductive main body portion 13, the size L2 of the transition portion 1422 is more than half of the size L1 of the conductive main body portion 13, and the greater the size L2 of the transition portion 1422, the better the current-carrying capacity of the transition portion 1422.

[0332] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1422 can be located at a middle position of the conductive main body portion 13, and both ends of the transition portion 1422 are not flush with the conductive main body portion 13.

[0333] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1422 can be located at a middle position of the conductive main body portion 13, and both ends of the transition portion 1422 are not flush with the conductive main body portion 13.

[0334] By adopting the technical scheme of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size L2 of the transition portion 1422 close to the size L1 of the conductive main body portion 13 along the second direction, the size of the transition portion 1422 is large, and the flow capacity of the transition portion 1422 is good, which is conducive to reducing heat generation and improving the fast-charging performance and use reliability of the battery monomer 100.

[0335] In some examples, L2=L1.

[0336] L2 / L1=1, along the second direction, the size L2 of the transition portion 1422 is equal to the size L1 of the conductive main body portion 13, and both ends of the transition portion 1422 are flush with the conductive main body portion 13 and form an equal-length structure.

[0337] By adopting the technical scheme of this embodiment, the transition portion 1422 forms an equal-length structure with the conductive main body, the flow capacity of the transition portion 1422 is better, and it is more conducive to reducing heat generation and improving the fast-charging performance and use reliability of the battery monomer 100.

[0338] In some examples, the first pole piece 1 further comprises a conductive member 30, the conductive member 30 comprises a first connecting portion 31 and a second connecting portion 32 arranged along the 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 away from the insulating base body 11, and the second connecting portion 32 is located at the side of the second conductive portion 142 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 can refer to a component for connecting the electrode lead-out portion 2011; the conductive member 30 is made of a metal material, for example, copper, aluminum, etc.; in the case of the first pole piece 1 being a positive pole piece, the conductive member 30 can be an aluminum foil; in the case of the first pole piece 1 being a negative pole piece, the conductive member 30 can 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 can be a portion connecting the conductive member 30 with the second conductive portion 142. The second connecting portion 32 can be a portion leading out from the first connecting portion 31 on a side of the active material layer 20 opposite to the insulating base body 11 in the first direction, i.e. in the thickness direction of the current collector 10, and protruding out of the insulating base body 11. The projection of the first connecting portion 31 is within the projection of the second conductive portion 142. The projection of the second connecting portion 32 is outside the projection range of the second conductive portion 142. In this way, the second conductive portion 142 and the electrode lead-out portion 2011 are connected at different positions on the conductive member 30, which facilitates the connection and reduces the mutual influence between the two connections, thus improving the connection reliability.

[0341] In some examples, the first connecting portion 31 can cover and connect with the second conductive portion 142. The second connecting portion 32 can lead out from the first connecting portion 31 on the side of the active material layer 20 opposite to the insulating base body 11 in the first direction, i.e. in the thickness direction of the current collector 10, and protrude out of the insulating base body 11. The projection of the first connecting portion 31 is within the projection of the second conductive portion 142. The projection of the second connecting portion 32 is outside the projection range of the second conductive portion 142. In this way, the second conductive portion 142 and the electrode lead-out portion 2011 are connected at different positions on the conductive member 30, which facilitates the connection and reduces the mutual influence between the two connections, thus improving the connection reliability. Of course, in other examples, the projection of the first connecting portion 31 and the projection of the second connecting portion 32 can also partially overlap in the thickness direction of the current collector 10.

[0342] For example, the first connecting portion 31 can be directly welded to the surface of the second conductive portion 142 opposite to the insulating base body 11. The welding connection operation is convenient and facilitates processing and manufacturing. Of course, the connection can also be achieved by other means.

[0343] For example, the second connecting portion 32 and the electrode lead-out portion 2011 can be connected by direct welding. The connection can also be achieved by welding through a conductive piece (e.g. a jumper). The welding connection operation is convenient and facilitates processing and manufacturing. Of course, the 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 base body 11 is located between two adjacent layers of the second conductive portion 142, so that the two adjacent layers of the second conductive portion 142 cannot be directly connected across the insulating base body 11 to transmit current outward, and the current can only be transmitted outward by the outermost layer of the second metal layer 12, which results in poor conductivity, low fast-charging performance and use reliability, and easy local overheating, which affects the use reliability of the battery monomer 100. The battery monomer 100 of the present application embodiment uses the first connecting portion 31 of the conductive member 30 to connect with the second conductive portion 142, and the second connecting portion 32 of the conductive member 30 can protrude out of the insulating base body 11. In this way, the second connecting portion 32 can electrically connect the two adjacent layers of the second conductive portion 142, thereby breaking the insulation limitation of the insulating base body 11, effectively improving the conductivity of the first electrode sheet 1, improving the fast-charging performance and use reliability of the battery monomer 100, reducing heat generation, and improving the use reliability of the battery monomer 100.

[0345] When the pole pieces are stacked to form the electrode assembly 101, the insulating base 11 is located between two adjacent metal layers 12, which makes it difficult to directly connect between the two adjacent metal layers 12 to pass current outward through the insulating base 11, so that the current can only be transmitted outward by the metal layer 12 located at the outermost side, resulting in poor conductivity, low fast-charging performance and use reliability, and easy to cause local overheating, affecting the use reliability of the battery monomer 100. The battery monomer 100 of the embodiment of the application utilizes the first connecting part 31 of the conductive member 30 to connect with the second conductive part 142, and the second connecting part 32 of the conductive member 30 can protrude outward from the insulating base 11. In this way, the second connecting part 32 can be used to electrically conduct between two adjacent second conductive parts 142, thereby breaking the insulation limit of the insulating base 11, effectively improving the conductivity of the first pole piece 1, improving the fast-charging performance and use reliability of the battery monomer 100, reducing heat generation, and improving the use reliability of the battery monomer 100.

[0346] By adopting the technical scheme of the embodiment, the second connecting part 32 protrudes outward from the second conductive part 142, which can facilitate the connection between the second connecting part 32 and the electrode lead-out part 2011, and the processing and manufacturing are more convenient.

[0347] In some embodiments, the first connecting part 31 is spaced apart from the active material layer 20 along the first direction.

[0348] The first connecting part 31 does not directly contact the active material layer 20, but there is a certain gap between them, so that the first connecting part 31 does not contact the active material layer 20.

[0349] In some examples, the first pole piece 1 is a positive pole piece, and the first connecting part 31 does not contact the active material layer 20, which can reduce the risk of lithium precipitation and the like, and is conducive to improving the use reliability of the battery monomer 100. In other examples, the first pole piece 1 is a negative pole piece, and the first connecting part 31 can contact or not contact the active material layer 20.

[0350] By adopting the technical scheme of the embodiment, the first connecting part 31 does not contact the active material layer 20, which can reduce the mutual influence between the two, and improve the use reliability of the battery monomer 100.

[0351] In some embodiments, the first connecting part 31 is welded to the surface of the second conductive part 142 away from the insulating base 11 and forms a first welding mark 51.

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

[0353] The first connecting portion 31 is welded with the second conductive portion 142, that is, the first connecting portion 31 is welded in the region where the metal layer 12 is not covered with the active material layer 20, so that the first connecting portion 31 is not easily welded to the active material layer 20, which is conducive to reducing the risk of problems such as false welding and improving the connection reliability and overcurrent capacity of the metal layer 12 and the conductive member 30.

[0354] By adopting the technical scheme of this embodiment, the first connecting portion 31 is welded with the second conductive portion 142, and the conductive member 30 is connected with the second conductive portion 142 in a welding manner, which is convenient for manufacturing the first tab 1. In addition, the second conductive portion 142 is small in thickness and large in surface area facing away from the insulating substrate 11, which is conducive to increasing the welding area between the first connecting portion 31 and the second conductive portion 142 and improving the overcurrent capacity between the first connecting portion 31 and the second conductive portion 142, and is conducive to improving the fast-charging performance and use reliability of the battery monomer 100. At the same time, the risk of problems such as false welding between the first connecting portion 31 and the second conductive portion 142 can be reduced, which is conducive to improving the connection reliability of the second conductive portion 142 and the conductive member 30 and is also conducive to improving the overcurrent capacity of the first tab 1 and the fast-charging performance and use reliability of the battery monomer 100.

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

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

[0358] By adopting the technical scheme of this embodiment, the first connecting portion 31 is welded with the protruding portion 1421, and the connection between the first connecting portion 31 and the protruding portion 1421 is in a welding manner, which is simple in connection mode and convenient for manufacturing the first tab 1. In addition, the first connecting portion 31 and the protruding portion 1421 can directly utilize the first welding mark portion 511 for overcurrent, which is conducive to improving the overcurrent capacity between the first connecting portion 31 and the protruding portion 1421.

[0359] In some embodiments, along the second direction, the first welding 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 portion 511 falls within the projection of the protruding portion 1421.

[0361] In the manufacturing process of the first tab 1, the conductive member 30 can be welded with the edge of the current collector 10 by ultrasonic welding (for example, double-roller continuous ultrasonic welding) or other welding methods to form a uniform-width welding portion, and then the conductive member 30 is cut by laser die cutting or other cutting methods to form a tab for easy connection with the electrode lead-out portion 2011; and in the cutting process, first cut along the second direction between the uniform-width welding portion and the active material layer 20, then cut towards the uniform-width welding portion until leaving the uniform-width welding portion, continue to cut away from the active material layer 20 for a distance, then cut along the second direction for a distance, then cut towards the uniform-width welding portion until leaving the uniform-width welding portion, and then cut along the second direction, so as to obtain a first welding portion 511, and repeat the above process, so as to obtain a plurality of first welding portions 511.

[0362] By adopting the technical scheme of the embodiment, along the second direction, the size L4 of the first welding portion 511 is large, which is beneficial to increase the flow area between the first connecting portion 31 and the protruding portion 1421, beneficial to increase the flow capacity between the first connecting portion 31 and the protruding portion 1421, beneficial to reduce the risk of heating, and beneficial to improve the fast-charging performance and use reliability of the battery monomer 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 size l2 of the first protruding sub-portion 14211 is greater than the size l3 of the second protruding sub-portion 14212; the first welding portion 511 includes a first welding sub-portion 5111, and the first connecting portion 31 is welded to the first protruding sub-portion 14211 to form the first welding sub-portion 5111.

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

[0365] By adopting the technical scheme of the embodiment, the first connecting portion 31 is welded with the first protruding sub-portion 14211 to form the first welding sub-portion 5111, and the first protruding sub-portion 14211 has a dimension l2 along the second direction, which is large, so as to facilitate increasing the welding area of the protruding portion 1421 and the first connecting portion 31, increasing the flow area between the protruding portion 1421 and the conductive portion, improving the flow capacity, reducing heat generation, and facilitating improving the fast-charging performance and use reliability of the battery monomer 100. In addition, along the second direction, the dimension l3 of the second protruding sub-portion 14212 is small, so as to facilitate reducing the occupied space of the protruding portion 1421 and facilitating improving the energy density of the battery monomer 100.

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

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

[0368] By adopting the technical scheme of the embodiment, along the second direction, the dimension of the first welding sub-portion 5111 is large, so as to facilitate increasing the welding area of the protruding portion 1421 and the first connecting portion 31, increasing the flow area between the protruding portion 1421 and the first connecting portion 31, improving the flow capacity, reducing heat generation, and facilitating improving the fast-charging performance and use reliability of the battery monomer 100.

[0369] In some embodiments, the protruding portion 1421 includes the first protruding sub-portion 14211 and the second protruding sub-portion 14212, and 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 of the first protruding sub-portion 14211 is larger than that of the second protruding sub-portion 14212. The first welding portion 511 includes the second welding sub-portion 5112, and the first connecting portion 31 is welded to the surface of the second protruding sub-portion 14212 away from the insulating substrate 11 to form the second welding sub-portion 5112.

[0370] For example, the surface of the second protruding sub-portion 14212 away from the insulating substrate 11 is welded with the first connecting portion 31, and the trace generated by the welding is the second welding sub-portion 5112.

[0371] By adopting the technical scheme of the embodiment, there is a gap between the second welding sub-portion 5112 and the active material layer 20, which can reduce the problem of false welding and the like, improve the welding reliability, and facilitate improving the use reliability of the battery monomer 100.

[0372] In some embodiments, the protruding portion 1421 comprises 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 size of the first protruding sub-portion 14211 is greater than the size of the second protruding sub-portion 14212; the first solder portion 511 comprises a first solder sub-portion 5111, the first connecting portion 31 is soldered to the first protruding sub-portion 14211 and forms the first solder sub-portion 5111; the first solder portion 511 further comprises a second solder sub-portion 5112, the first connecting portion 31 is soldered to the surface of the second protruding sub-portion 14212 away from the insulating base 11 and forms the second solder sub-portion 5112.

[0373] By adopting the technical solutions of this embodiment, the first protruding sub-portion 14211 and the second protruding sub-portion 14212 are both soldered to the first connecting portion 31, which is conducive to increasing the flow area between the first connecting portion 31 and the protruding portion 1421, and is conducive to improving the flow capacity between the first connecting portion 31 and the protruding portion 1421.

[0374] In some embodiments, along the second direction, the second solder sub-portion 5112 extends from one side edge of the second protruding sub-portion 14212 to the other side edge of the second protruding sub-portion 14212.

[0375] Along the first direction, the projection of the second solder sub-portion 5112 falls within the projection of the second protruding sub-portion 14212.

[0376] By adopting the technical solutions of this embodiment, the size of the second solder sub-portion 5112 along the second direction is large, which is conducive to increasing the soldering area between the first connecting portion 31 and the protruding portion 1421, increasing the flow area between the first connecting portion 31 and the protruding portion 1421, and improving the flow capacity between the first connecting portion 31 and the protruding portion 1421.

[0377] In some embodiments, the number of protruding portions 1421 is a plurality, and the plurality of protruding portions 1421 are arranged at intervals along the second direction; the first connecting portion 31 comprises a plurality of first connecting sub-portions 311, the plurality of first connecting sub-portions 311 are arranged at intervals along the second direction, and the number of second connecting portions 32 is a plurality, each first connecting sub-portion 311 is connected to each second connecting portion 32 one-to-one; each first connecting sub-portion 311 is soldered to the surface of each protruding portion 1421 away from the insulating base 11 one-to-one.

[0378] The first connecting sub-part 311 can 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 corresponds to one second connecting part 32, and one first connecting sub-part 311 and one protruding part 1421 form one first welding part 511.

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

[0380] Please refer to FIGS. 11-21, 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, along 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 of the current collector 10 and the first direction; the first welding mark 51 further includes a second welding part 512, and the first connecting part 31 is welded to the surface of the transition part 1422 away from the insulating substrate 11 and forms the second welding part 512.

[0381] The first connecting part 31 is welded to the surface of the transition part 1422 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 part 512.

[0382] In some examples, the first welding mark 51 includes the second welding part 512 and the first welding part 511, that is, the first connecting part 31 is welded to the transition part 1422 and the protruding part 1421 at the same time, and the first welding part 511 is located between the second welding part 512 and the active material layer 20.

[0383] In some examples, the first welding mark 51 only includes the second welding part 512, that is, the first connecting part 31 is only welded to the transition part 1422, at this time, the first connecting part 31 and the second conductive part 142 only pass through the flow part for flow, so that the protruding part 1421 is not needed for flow, and the heat generation risk at the junction of the protruding part 1421 and the flow part is reduced, which is conducive to improving the fast charging performance of the battery monomer 100.

[0384] By adopting the technical scheme of the embodiment, the first connecting part 31 and the transition part 1422 are connected in a welding manner, the connection manner is simple, and the first pole piece 1 is convenient to manufacture; in addition, along the second direction, the size of the transition part 1422 is large, the flow capacity of the transition part 1422 is good, the first connecting part 31 and the first conductive part 141 can directly utilize the transition part 1422 to flow, so that the flow pressure between the protruding part 1421 and the flow part can be reduced, even without the flow of the protruding part 1421, the risk of heat production is reduced, and the fast-charging performance of the battery monomer 100 is improved.

[0385] In some embodiments, the first welding mark 51 can be only the first welding part 511, that is, the first connecting part 31 is welded with the protruding part 1421, and is not welded with the transition part 1422.

[0386] In some embodiments, the first welding mark 51 can be only the second welding part 512, that is, the first connecting part 31 is welded with the transition part 1422, and is not welded with the protruding part 1421.

[0387] In some embodiments, along the second direction, the size of the transition part 1422 is L2, the size of the second welding part 512 is L3, and 0.8≤L3 / L2≤1.

[0388] 0.8≤L3 / L2≤1, along the second direction, the size L3 of the second welding part 512 can be less than or equal to the size L2 of the transition part 1422, the size L3 of the second welding part 512 is more than 0.8 times the size L2 of the transition part 1422, the size L3 of the second welding part 512 exceeds more than half the size L2 of the transition part 1422, the longer the size L3 of the second welding part 512, the larger the welding area of the transition part 1422 and the first connecting part 31, and the better the flow capacity of the connection between the transition part 1422 and the first connecting part 31.

[0389] In some examples, 0.8≤L3 / L2<1, along the second direction, the second welding part 512 can be located at the middle position of the transition part 1422, and the two ends of the second welding part 512 are not flush with the transition part 1422.

[0390] In some examples, 0.8≤L2 / L1<1, along the second direction, the second welding part 512 can also be arranged to be deviated from one end of the transition part 1422, so that one end of the transition part 1422 is flush with the transition part 1422, and the other end is not flush, or both ends are not flush.

[0391] The value of L3 / L2 can be but is not limited to 0.8, 1 or any value between 0.8 and 1. For example, the value of L3 / L2 can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0392] By adopting the technical scheme of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the second welding portion 512 larger along the second direction, which is beneficial to increase the welding area between the first connecting portion 31 and the transition portion 1422, improve the flow capacity at the connection between the first connecting portion 31 and the transition portion 1422, improve the flow capacity of the first pole piece 1, reduce heat generation, and improve the fast-charging performance and use reliability of the battery monomer 100.

[0393] In some embodiments, L3=L2.

[0394] L3 / L2=1, along the second direction, the size L3 of the second welding portion 512 is equal to the size L2 of the transition portion 1422, and along the second direction, the two ends of the second welding portion 512 are flush with the transition portion 1422.

[0395] In some examples, the protruding portion 1421 and the transition portion 1422 are welded to the first connecting portion 31 at the same time, thereby forming an entire welding mark, and the first connecting portion 31 is welded to the transition portion 1422, which can effectively increase the welding area of the first connecting portion 31 and the metal layer 12 and improve the flow area between the first connecting portion 31 and the metal layer 12, which is beneficial to improve the flow capacity between the first connecting portion 31 and the metal layer 12.

[0396] By adopting the technical scheme of this embodiment, the design of L3 / L2=1 makes the size of the second welding portion 512 larger along the second direction, which is beneficial to design the welding area between the first connecting portion 31 and the transition portion 1422 to be larger, the flow capacity at the connection between the first connecting portion 31 and the transition portion 1422 is best, which can effectively improve the flow capacity of the first pole piece 1, reduce heat generation, and improve the fast-charging performance and use reliability of the battery monomer 100.

[0397] 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; the first connecting portion 31 includes a second connecting sub-portion 312 and multiple first connecting sub-portions 311, and the multiple first connecting sub-portions 311 are arranged at intervals along the second direction, and each first connecting sub-portion 311 corresponds to each protruding portion 1421; the number of the second connecting portions 32 is multiple, and along the first direction, one side of each first connecting sub-portion 311 is connected to each second connecting portion 32 one by one, 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 arranged continuously along the second direction; and the second connecting sub-portion 312 is welded to the surface of the transition portion 1422 away from the insulating base body 11.

[0398] The second connecting sub portion 312 can refer to the portion of the first connecting portion 31 covering the transition portion 1422; the second connecting sub portion 312 is continuously arranged along the second direction, and for example, along the second direction, the second connecting sub portion 312 extends from one side 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 away from the insulating substrate 11 to form the second welding mark portion 512.

[0400] In some examples, during the cutting of the conductive member 30, first cutting is performed on the equal-width welding mark along the second direction, then cutting is performed along the direction away from the active material layer 20 until the equal-width welding mark is left, then a distance is cut along the direction away from the active material layer 20, then a distance is cut along the second direction, then a distance is cut along the direction toward the active material layer 20 until the equal-width welding mark is cut, then cutting is continued along the second direction on the equal-width welding mark, and so on, so as to obtain the first welding mark 51; wherein, based on the cutting position of the equal-width welding mark along the second direction as a reference, along the first direction, the second welding portion 512 is located on the portion of the first welding mark 51 on the side of the cutting position toward the active material layer 20, and the first welding portion 511 is located on the portion of the first welding mark 51 on the side of the cutting position away from the active material layer 20, and the first welding portion 511 can be a protruding structure of the second welding portion 512 away from the active material layer 20; and during the cutting process from the direction away from the active material layer 20 to the direction toward the active material layer 20 after the cutting is completed, the metal layer 12 of the current collector 10 cuts out the protruding portion 1421, and the conductive member 30 cuts out the second connecting portion 32 and the first connecting sub portion 311, and during the cutting along the second direction, the portion between the protruding portion 1421 and the active material layer 20 forms the transition portion 1422, and the conductive member 30 cuts out the second connecting sub portion 312.

[0401] By adopting the technical scheme of this embodiment, the second connecting sub portion 312 is continuously arranged along the second direction, a plurality of first connecting sub portions 311 can be connected as a whole, the second connecting sub portion 312 can provide good support to the first connecting sub portion 311, the risk of the first connecting sub portion 311 bending and being inserted between the first and second pole pieces 1 and 2 can be reduced, the risk of short circuit can be reduced, and the use reliability of the battery monomer 100 can be improved; in addition, along the second direction, the size of the second connecting sub portion 312 is large, which is beneficial to increasing the welding area between the second connecting sub portion 312 and the transition portion 1422, beneficial to increasing the overcurrent capacity of the connection between the first connecting portion 31 and the transition portion 1422, beneficial to increasing the overcurrent capacity of the first pole piece 1, and beneficial to improving the fast-charging performance and use reliability of the battery monomer 100.

[0402] In some embodiments, along the second direction, the size L4 of the first welding portion 511 is smaller than the size L3 of the second welding portion 512.

[0403] By adopting the technical solutions of this embodiment, along the second direction, the size L3 of the second welding portion 512 is large, the welding area of the transition portion 1422 and the first connecting portion 31 is large, which is conducive to improving the flow capacity of the first connecting portion 31 and the transition portion 1422, and is conducive to improving the fast-charging performance and use reliability of the battery monomer 100.

[0404] 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, and each protruding portion 1421 is welded with the first connecting portion 31 and forms the first welding portion 511.

[0405] The number of the protruding portions 1421 is multiple, for example, two, three, four, etc., and the multiple 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 multiple protruding portions 1421 are stacked together, and at the same time, the multiple second connecting portions 32 are also stacked together, thereby breaking the insulation limit of the insulating base body 11, effectively improving the conductivity of the first pole piece 1, improving the fast-charging performance of the battery device 1100 monomer, reducing the heat production of the battery device 1100 monomer, and improving the use reliability of the battery device 1100 monomer.

[0407] The multiple protruding portions 1421 are arranged at intervals along the second direction, so that along the second direction, the sum of the sizes l1 of all the protruding portions 1421 is smaller than the size L2 of the transition portion 1422, the sum of the sizes L4 of all the first welding portions 511 is smaller than the size L3 of the second welding portion 512, the size L3 of the second welding portion 512 is large, which is conducive to improving the welding area of the transition portion 1422 and the first connecting portion 31, conducive to improving the flow capacity of the connection between the transition portion 1422 and the conductive member 30, conducive to improving the flow capacity of the first pole piece 1, reducing heat production, and improving the fast-charging performance and use reliability of the battery monomer 100.

[0408] Among the multiple first welding portions 511, along the second direction, the size L4 of some of the first welding portions 511 can be the same, or the size L4 of all the first welding portions 511 can be completely different, or the size L4 of all the first welding portions 511 can be the same.

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

[0410] The second welding portion 512 and the first welding portion 511 form a whole first welding 51, and there is no obvious boundary between the two; the whole first welding 51 can cover the junction of the protruding portion 1421 and the transition portion 1422; in the actual manufacturing process, the second welding portion 512 and the first welding portion 511 are formed by cutting the above-mentioned welding with equal width.

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

[0412] By adopting the technical scheme of this embodiment, the first welding 51 can cover the junction of the protruding portion 1421 and the transition portion 1422, a part of the current can directly flow to the first connecting portion 31 through the transition portion 1422, the overcurrent pressure at the junction of the protruding portion 1421 and the transition portion 1422 is reduced, which is beneficial to improve the overcurrent capacity of the first electrode tab 1, reduce the heat generation, and is beneficial to improve the fast-charging performance and use reliability of the battery monomer 100.

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

[0414] The insulating piece 40 can refer to a component capable of insulation, the insulating piece 40 comprises the first insulating portion 41, the first insulating portion 41 can refer to an insulating component covering the surface of the metal layer 12 away from the active material layer 20; the first insulating portion 41 can be but not limited to an insulating coating, an insulating glue (for example: hot melt glue) or an insulating adhesive tape.

[0415] In the thickness direction of the current collector 10, the first insulating portion 41 is not coincident with the first welding 51, and the first insulating portion 41 is arranged in a spaced manner with the first welding 51, so that the first connecting portion 31 will not be welded to the first insulating portion 41, which is beneficial to reduce the risk of false welding between the first connecting portion 31 and the metal layer 12; or, the first insulating portion 41 is only coincident with the first welding 51 at the edge, the edge of the first welding 51 is coincident with the edge of the first insulating portion 41, the risk of false welding is small, and the welding reliability between the first connecting portion 31 and the metal layer 12 is good.

[0416] By adopting the technical solutions of this embodiment, the first insulating portion 41 can insulate the surface of the second conductive portion 142 away from the surface of the insulating base body 11 and other components, which is conducive to improving the use reliability of the battery monomer 100, and is conducive to improving the connection reliability of the first connecting portion 31 and the metal layer 12, and is conducive 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, in the case where the first connecting portion 31 is welded only with the protruding portion 1421 and the first connecting portion 31 is arranged in a spaced manner with 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 can cover only the transition portion 1422.

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

[0421] By adopting the technical solutions of this embodiment, the first insulating portion 41 can support the part of the second conductive portion 142 located between the first connecting portion 31 and the active material layer 20, which can reduce the damage such as cracks and fractures of this part during the manufacturing process of the battery device 1100, and is conducive to improving the electronic transmission capacity of this part and the fast charging performance and use reliability of the battery monomer 100. In addition, the first insulating portion 41 can also realize the insulation of this part, reduce the risk of short circuit of the battery monomer 100, and improve the use reliability of the battery monomer 100.

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

[0423] The second insulating portion 42 can be an insulating component covering the first welding mark 51, and the first insulating portion 41 and the second insulating portion 42 can be an integrally formed structure or two separate components connected.

[0424] The second insulating portion 42 can be, but is not limited to, an insulating coating, an insulating glue (for example, hot melt glue), or an insulating adhesive tape.

[0425] A part of the first insulating portion 41 can cover the first welding 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 welding mark 51.

[0426] By adopting the technical scheme of this embodiment, the surface of the first welding mark 51 can generate a pointed protrusion, metal debris and the like, the second insulating part 42 covers the surface of the first welding mark 51, can block the pointed protrusion, metal debris and the like from contacting the second pole piece 2, reduces the short circuit risk of the battery monomer 100, and improves the use reliability of the battery monomer 100.

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

[0428] It can be understood that one side of the second insulating part 42 covers the first welding mark 51, and the other side of the second insulating part 42 can cover the entire first insulating part 41, or cover part of the first insulating part 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 part of the first insulating part 41, the second insulating part 42 can also cover the part of the first connecting part 31 located between the first insulating part 41 and the first welding mark 51, and the covering of the insulating part 40 is more comprehensive, which is more conducive to reducing the short circuit risk and improving the use reliability of the battery monomer 100.

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

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

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

[0433] By adopting the technical scheme of this embodiment, the surface of the first welding mark 51 can generate a pointed protrusion, metal debris and the like, the second insulating part 42 covers the surface of the first welding mark 51, can block the pointed protrusion, metal debris and the like from contacting the second pole piece 2, reduces the short circuit risk of the battery monomer 100, and improves the use reliability of the battery monomer 100.

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

[0435] The second insulation part 42 covers one side of the first solder print 51, and covers the other side of the second insulation part 42 directly on a part of the active material layer 20 or the entire active material layer 20. For example, the second insulation part 42 covers the end of the first active material part 21 away from the second active material part 22, so that the first active material part 21 provides installation space for the second insulation part 42, and reduces the risk of the surface of the first active material part 21 away from the insulation base 11 protruding to the surface of the second active material part 22 away from the insulation base 11. Of course, the second insulation part 42 can cover a part of the first active material part 21 and the second active material part 22, or cover the entire active material layer 20.

[0436] In some examples, the second conductive part 142 is covered with the first insulation part 41, and the second insulation part 42 extends to the active material layer 20 after covering the first insulation part 41, so as to cover the active material layer 20.

[0437] In some examples, the second conductive part 142 is not covered with the first insulation part 41, and the second insulation part 42 extends from the first solder print 51 to the active material layer 20, so as to cover the part of the second conductive part 142 between the conductive member 30 and the active material layer 20, reduce the risk of short circuit of this part, and improve the use reliability of the battery monomer 100. In addition, the first insulation part 41 can be omitted to save costs, and the active material layer 20 can be used to cover the original position of the first insulation part 41, so as to improve the fast charging performance and use reliability of the active material layer 20, and improve the energy density of the battery monomer 100.

[0438] By adopting the technical scheme of the embodiment, the second insulation part 42 extends from the first solder print 51 to the active material layer 20, and the second insulation part 42 has a wide coverage area and good insulation effect.

[0439] In some embodiments, in the first direction, the size of the part of the insulation part 40 covering the active material layer 20 is H, wherein 0.2mm≤H≤1.0mm, and optionally, 0.3mm≤H≤0.8mm.

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

[0441] The design of H≥0.2mm enables the insulation member 40 to cover the end of the active material layer 20 towards the conductive part 14, and the insulation member 40 can block burrs at the end of the active material layer 20 towards the conductive part 14, thereby improving the use reliability of the battery monomer 100; the design of H≤1.0mm enables the insulation member 40 to cover a part of the active material layer 20 without being too large, which is conducive to reducing the weight and volume of the insulation member 40 and improving the energy density of the battery monomer 100.

[0442] In some examples, the insulation member 40 includes a first insulation part 41 covering the end of the active material layer 20 towards the conductive part 14, and the part of the active material layer 20 covered by the first insulation part 41 can refer to a mutual dissolution area formed by the first insulation part 41 and the active material layer 20, so that the fixation of the first insulation part 41 is more stable.

[0443] In some examples, the insulation member 40 includes a second insulation part 42 covering the end of the active material layer 20 towards the extension part.

[0444] By adopting the technical scheme of this embodiment, along the first direction, the size of the part of the active material layer 20 covered by the insulation member 40 is reasonable, and the burrs at the end of the active material layer 20 close to the conductive part 14 and the energy density of the battery monomer 100 can be considered at the same time.

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

[0446] By adopting the technical scheme of this embodiment, along the first direction, the size of the part of the active material layer 20 covered by the second insulation part 42 is more reasonable, and the burrs at the end of the active material layer 20 close to the conductive part 14 and the energy density of the battery monomer 100 can be considered at the same time.

[0447] In some examples, the number of the metal layers 12 is two, the two metal layers 12 are arranged on opposite sides of the insulating substrate 11 along the thickness direction of the current collector 10, the number of the active material layers 20 is two, the two active material layers 20 respectively cover the two metal layers 12, the number of the conductive members 30 is two, the first connecting parts 31 of the two conductive members 30 are respectively welded to the second conductive parts 142 of the two metal layers 12 and form two first welding marks 51, and the number of the insulation members 40 is two, the second insulation parts 42 of the two insulation members 40 respectively cover at least part of the two first welding marks 51.

[0448] The number of the metal layers 12, the number of the insulating pieces 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 along the thickness direction, the two active material layers 20 respectively cover the first conductive parts 141 and the conductive main body parts 13 of the two metal layers 12; the first connecting part 31 of one conductive member 30 is welded to the surface of the second conductive part 142 of one metal layer 12 away from the insulating substrate 11 and forms the first welding mark 51, the first connecting part 31 of the other conductive member 30 is welded to the second conductive part 142 of the other metal layer 12 and also forms the first welding mark 51, and the second insulating parts 42 of the two insulating pieces 40 cover the two first welding marks 51.

[0449] By adopting the technical scheme of the embodiment, the first connecting parts 31 of the two conductive members 30 are welded to the metal layers 12 located on opposite sides of the insulating substrate 11, and the second connecting parts 32 of the two conductive members 30 are located on the side of the second conductive part 142 away from the first conductive part 141, so that the two conductive parts 14 can be directly connected by the second connecting parts 32 of the two conductive members 30, thereby breaking the insulation limitation of the insulating substrate 11, effectively improving the conductive capacity of the first tab 1, improving the fast charging performance of the battery monomer 100, reducing heat generation, and improving the use reliability of the battery monomer 100.

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

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

[0452] By adopting the technical scheme of the embodiment, along the direction of the conductive main body part 13 pointing to the conductive part 14, the metal debris and other components at the side of the second conductive part 142 away from the active material layer 20 can be located between the second parts 422 of the two insulating pieces 40, so as to reduce the risk of metal debris falling into the electrode assembly 101 and facilitate reducing the risk of short circuit.

[0453] In some embodiments, the second parts 422 of the two insulating pieces 40 are in abutment.

[0454] In some examples, the second portions 422 of the two insulating pieces 40 do not extend into the hollowed-out area of the protrusion 1421 at the transition 1422, and the second portions 422 of the two insulating pieces 40 can be close to each other and abut together.

[0455] The second portions 422 of the two insulating pieces 40 can be adhered or statically adsorbed together, and of course can also be other abutting manners.

[0456] By adopting the technical solutions of this embodiment, after the second portions 422 of the two insulating pieces 40 abut together, the metal scraps and other components at the side of the second conductive part 142 can be covered, so that the metal scraps and other components are not easy to fall into the electrode assembly 101, and the risk of short circuit of the battery monomer 100 can be better reduced.

[0457] In some embodiments, the second connecting parts 32 of the two conductive members 30 are welded and form second welding marks 52 in a direction from the conductive main body part 13 to the conductive part 14.

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

[0459] By adopting the technical solutions of this embodiment, after the second connecting parts 32 of the two conductive members 30 are welded, the second conductive parts 142 located on opposite sides of the insulating base body 11 can be connected, thereby breaking the insulation limitation of the insulating base body 11, the conductive capacity of the first pole piece 1 can be effectively improved, the fast-charging performance of the battery monomer 100 can be improved, the heat generation can be reduced, and the use reliability of the battery monomer 100 can be improved.

[0460] In some embodiments, the second insulating part 42 covers the second welding mark 52, and in a 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 welding mark 52 away from the conductive main body part 13.

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

[0462] By adopting the technical solutions of this embodiment, the second insulating part 42 can completely cover the second welding mark 52, and can block the burrs, metal scraps and other components on the second welding mark 52 from piercing the separator 3 to connect with the second pole piece 2, thereby reducing the risk of short circuit and improving the use reliability of the battery monomer 100.

[0463] In some embodiments, the electrode assembly 101 comprises a second tab 2 opposite in polarity to the first tab 1, the second tab 2 comprises a main functional portion 210 and a tab portion 220, the tab portion 220 protrudes the main functional portion 210 in a first direction; the main functional portion 210 protrudes an end surface of the insulating member 40 toward the active material layer 20 in a direction of the conductive portion 14 pointing to the conductive main portion 13, and the main functional portion 210 does not protrude an end surface of the insulating member 40 away from the active material layer 20.

[0464] The second tab 2 can refer to a tab opposite in polarity to the first tab 1, where the first tab 1 is a positive tab and the second tab 2 is a negative tab, or the first tab 1 is a negative tab and the second tab 2 is a positive tab. The first tab 1 and the second tab 2 can be stacked and then wound to form a wound electrode assembly 101; a plurality of first tabs 1 and a plurality of second tabs 2 are stacked to form a laminated electrode assembly 101.

[0465] The second tab 2 comprises a main functional portion 210 and a tab portion 220, the main functional portion 210 can refer to the main part of the second tab 2, and the tab portion 220 can refer to the part of the second tab 2 protruding the main functional portion 210; in the case of the second tab 2 being a negative tab, the tab portion 220 can refer to the protruding structure at the edge of the negative current collector 10, and the main functional portion 210 can include the part of the negative current collector 10 except the protruding structure and the negative active material layer 20. In the case of the second tab 2 being a positive tab, the tab portion 220 can refer to the protruding structure at the edge of the positive current collector 10, and the main functional portion 210 can include the part of the positive current collector 10 except the protruding structure and the positive active material layer 20.

[0466] During the manufacturing process of the second tab 2, the edge of the second tab 2 is die-cut to obtain the tab portion 220 and the main functional portion 210, and during the die-cutting process, burrs are easily generated at the end surface of the main functional portion 210 toward the tab portion 220.

[0467] For example, in the thickness direction of the current collector 10, the projection of the end surface of the main functional portion 210 close to the tab 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 scheme of this embodiment, the insulating member 40 can block the burrs at the end surface of the main functional portion 210 of the second tab 2 close to the tab portion 220 from piercing the separator 3 to connect with the first tab 1, thereby reducing the risk of short circuit between the first tab 1 and the second tab 2, and facilitating to improve the use reliability of the battery monomer 100.

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

[0470] The second insulation portion 42 can be connected to the metal layer 12, the conductive member 30, or the active material layer 20. The second insulation portion 42 can be connected to the first tab 1 by adhesion or pasting.

[0471] By adopting the technical scheme of this embodiment, the second insulation portion 42 is connected to the first tab 1, and the second insulation portion 42 is fixed, thereby stably blocking the burrs, metal debris, and other components, which is conducive to reducing the short circuit risk of the battery monomer 100 and improving the use reliability of the battery monomer 100.

[0472] Please refer to FIGS. 22 and 23, in some embodiments, the second insulation portion 42 includes an insulation base layer 423 and an adhesive layer 424, and the adhesive layer 424 is adhered between the insulation base layer 423 and the first tab 1.

[0473] The second insulation portion 42 adopts the structure of a tape; the insulation base layer 423 can be the main part of the second insulation portion 42, and the adhesive layer 424 can be an adhesive covering the surface of the insulation base layer 423. The material of the insulation base layer 423 includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and a block copolymer thereof. 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 scheme of this embodiment, the second insulation portion 42 adopts the structure of a tape, which is easy to cover comprehensively, thereby reducing the risk of missing coverage and reducing the internal short circuit risk of the battery monomer 100. The insulation base layer 423 can improve the structural strength of the second insulation portion 42 and reduce the deformation of the second insulation portion 42 during the pasting process, thereby improving the insulation effect. The adhesive layer 424 can stably fix the insulation base layer 423 to the first tab 1 and reduce the risk of falling off of the insulation tape.

[0475] In some embodiments, the thickness of the insulation base layer 423 ranges from 6 μm to 15 μm.

[0476] The thickness of the insulation base layer 423 is T1, and 6 μm≤T1≤15 μm. It can be understood that the value of T1 can be 6 μm, 15 μm, and any value between 6 μm and 15 μm. For example, the value of T1 can be, but is not limited to, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm.

[0477] The design of T1≥6μm makes the insulating base layer 423 have a certain thickness to block burrs and achieve insulation; the design of T1≤15μm makes the thickness of the insulating base layer 423 not too large, which is conducive to reducing the volume occupied by the second insulating part 42 and improving the energy density of the battery monomer 100.

[0478] By adopting the technical solutions of this embodiment, the internal insulation and the energy density of the battery monomer 100 can be considered at the same time.

[0479] In some embodiments, the layer thickness of the bonding layer 424 ranges from 0.5μm to 3μm.

[0480] The layer thickness of the bonding layer 424 is T2, and 0.5μm≤T2≤3μm. It can be understood that the value of T2 can be 0.3μm, 3μm, and any value between 0.3μm and 3μm. For example, the value of T2 can be, but is not limited to, 0.3μm, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, and 3μm.

[0481] The design of T2≥0.5μm makes the bonding layer 424 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; the design of T2≤3μm makes the thickness of the bonding layer 424 not too large, which is conducive to reducing the volume occupied by the second insulating part 42 and improving the energy density of the battery monomer 100.

[0482] By adopting the technical solutions of this embodiment, the insulation reliability and the energy density of the battery monomer 100 can be considered at the same time.

[0483] In some embodiments, the layer thickness of the insulating base layer 423 ranges from 6μm to 15μm; and the layer thickness of the bonding layer 424 ranges from 0.5μm to 3μm.

[0484] By adopting the technical solutions of this embodiment, the insulation reliability and the energy density of the battery monomer 100 can be considered at the same time.

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

[0486] In some examples, the insulating piece 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 piece 40 includes the second insulating part 42 and the first insulating part 41, and S is equal to the overall size of the second insulating part 42 and the insulating coating along 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, for 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 of S≥3mm makes the insulation piece 40 have a certain size in the first direction, which is beneficial to the internal insulation of the battery monomer 100; the design of S≤9mm makes the size S of the insulation piece 40 in the first direction not too large, which is beneficial to reduce the volume occupied by the insulation piece 40 and improve the energy density of the battery monomer 100.

[0490] By adopting the technical scheme of this embodiment, the insulation reliability and energy density of the battery monomer 100 can be considered at the same time.

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

[0492] By adopting the technical scheme of this embodiment, the size S of the insulation piece 40 in the first direction is reasonable, and the insulation reliability and energy density of the battery monomer 100 can be considered at the same time.

[0493] In some embodiments, the electrode assembly 101 includes a second pole piece 2 opposite to the first pole piece 1 in polarity, the second pole piece 2 includes a main body functional part 210 and a tab part 220, the tab part 220 protrudes from the main body functional part 210 in the first direction; in the direction of the conductive main body part 13 pointing to the conductive part 14, the main body functional part 210 protrudes from the end face of the conductive part 14 away from the conductive main body part 13.

[0494] In some examples, in the thickness direction of the current collector 10, the projection of the main body functional part 210 toward the end face of the tab part 220 does not coincide with the projection of the metal layer 12, and the burr of the main body functional part 210 of the second pole piece 2 at the end face toward the tab part 220 corresponds to the hollow area of the metal layer 12 not extending out of the second connecting part 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 body functional part 210, and the first welding mark 51 can be covered with the second insulation part 42, so that the second insulation part 42 can block the burr, metal debris and other components on the first welding mark 51 from piercing the separator 3 and connecting with the second pole piece 2, reducing the risk of short circuit and improving the use reliability of the battery monomer 100.

[0496] By adopting the technical scheme of the embodiment, the burr of the main body functional part 210 of the second tab 2 towards the end face of the tab part 220 corresponds to the hollowed-out area where the metal layer 12 does not extend out of the second connecting part 32, and the short circuit risk of the battery monomer 100 can also be reduced, and the use reliability of the battery monomer 100 is improved.

[0497] In some embodiments, the first welding mark 51 is spaced apart from the active material layer 20 by a distance S1 in the first direction, where 0.5mm≤S1≤5mm.

[0498] The design of S1≥0.3mm makes the first welding mark 51 spaced apart from the active material layer 20, so that the conductive member 30 is not welded to the active material layer 20, reducing the risk of problems such as false welding; the design of S1≤5mm makes the distance between the first welding mark 51 and the active material layer 20 not too large, which is conducive to improving the coverage area of the active material layer 20 on the metal layer 12 and improving the energy density of the battery monomer 100.

[0499] The value of S1 can be 0.3mm, 5mm, and any value between 0.3mm and 5mm, for example, the value of S1 can be but is not limited to 0.3mm, 0.5mm, 1mm, 2mm, 2.5mm, 2.8mm, 3mm, 4mm, 5mm.

[0500] By adopting the technical scheme of the embodiment, the design of 0.3mm≤S1≤5mm makes the first welding mark 51 not welded to the active material layer 20, reducing problems such as false welding, and is conducive to improving the connection reliability of the first connecting part 31 and the metal layer 12. In addition, the distance between the active material layer 20 and the first welding mark 51 is small, and the active material layer 20 can be closer to the first welding mark 51. Therefore, under the condition that the size of the metal layer 12 in the first direction is constant, the active material layer 20 can cover a larger area, which is conducive to improving the energy density of the battery monomer 100.

[0501] In some embodiments, 0.5mm≤S1≤2.8mm.

[0502] By adopting the technical scheme of the embodiment, the design of 0.5mm≤S1≤2.8mm makes the distance between the active material layer 20 and the first welding mark 51 more reasonable, and better balances the connection reliability of the conductive member 30 and the energy density of the battery monomer 100.

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

[0504] In some examples, the first tab 1 is a positive tab, and a gap exists between the first solder print 51 and the active material layer 20. The gap can be used to provide a spacing space between the conductive member 30 and the active material layer 20, so as to reduce the risk of lithium precipitation caused by the contact between the conductive member 30 and the active material layer 20. In addition, the gap can also provide a spacing space for the end surface of the first solder print 51 and the first connecting portion 31 facing the active material layer 20, so that the first solder print 51 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, reducing the risk of the end surface of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, and facilitating the reduction of burrs generated by welding and the improvement of the use reliability of the battery monomer 100.

[0505] In some examples, the first tab 1 is a negative tab, and a gap exists between the first solder print 51 and the active material layer 20. The gap can provide a spacing space for the end surface of the first solder print 51 and the first connecting portion 31 facing the active material layer 20, so that the second solder print 52 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, reducing the risk of the end surface of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, and facilitating the reduction of burrs generated by welding and the improvement of the use reliability of the battery monomer 100. The conductive member 30 can or can not be connected to the active material layer 20.

[0506] A gap exists between the first solder print 51 and the end surface of the first connecting portion 31 facing the active material layer 20, so that the first solder print 51 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, reducing the risk of the end surface of the first connecting portion 31 facing the active material layer 20 being welded through or cracked, and facilitating the reduction of burrs generated by welding and the improvement of the use reliability of the battery monomer 100.

[0507] In some embodiments, along the first direction, the distance between the first solder print 51 and the end surface of the first connecting portion 31 facing the active material layer 20 is S2, where 0.3mm≤S2≤1.2mm.

[0508] The design of S2≥1.2mm makes a distance exist between the first solder print 51 and the end surface of the first connecting portion 31 facing the active material layer 20, so that the first solder print 51 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, reducing the risk of the end surface of the first connecting portion 31 facing the active material layer 20 being welded through or cracked. The design of S2≤1.2mm makes the distance between the first solder print 51 and the end surface of the first connecting portion 31 facing the active material layer 20 not too large, which is conducive to improving the coverage area of the active material layer 20 on the metal layer 12 and improving the energy density of the battery monomer 100.

[0509] The value of S2 can be 0.3 mm, 1.2 mm, and any value between 0.3 mm and 1.2 mm. For example, the value of S2 can be, but is not limited to, 0.3 mm, 0.6 mm, 0.8 mm, 1 mm, and 1.2 mm.

[0510] By adopting the technical solutions of this embodiment, the use reliability and energy density of the battery monomer 100 can be well balanced.

[0511] In some embodiments, in the first direction, the size of the conductive part 14 is W4, and the size of the conductive main body part 13 is W5, where 0.01≤W4 / W5≤0.8.

[0512] The size W5 of the conductive main body part 13 can be the width of the conductive main body part 13.

[0513] 0.01≤W4 / W5≤0.8. It can be understood that the value of W4 / W5 can be 0.01, 0.8, and any value between 0.01 and 0.8. For example, the value of W4 / W5 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, and 0.8.

[0514] By adopting the technical solutions of this embodiment, the design of 0.01≤W4 / W5≤0.8 makes the ratio of the size of the conductive part 14 to the size of the conductive main body part 13 in the first direction reasonable, which can improve the overcurrent capacity at the conductive part 14, improve the fast charging performance and use reliability of the battery monomer 100, and in addition, the size of the conductive part 14 in the first direction is not too large, which is conducive to reducing the occupied space and weight of the conductive part 14 and improving the energy density of the battery monomer 100.

[0515] In some embodiments, 0.05≤W4 / W5≤0.6.

[0516] By adopting the technical solutions of this embodiment, the design of 0.05≤W4 / W5≤0.6 makes the ratio of the size of the conductive part 14 to the size of the conductive main body part 13 in the first direction more reasonable, which can improve the overcurrent capacity at the conductive part 14, improve the fast charging performance and use reliability of the battery monomer 100, and in addition, the size of the conductive part 14 in the first direction is not too large, which is conducive to reducing the occupied space and weight of the conductive part 14 and improving the energy density of the battery monomer 100.

[0517] In some embodiments, the thickness of the conductive main body part 13 is t1, and the maximum thickness of the conductive part 14 is t4, where 0.2 μm≤t4-t1≤4.5 μm.

[0518] For example, the maximum thickness t4 of the conductive part 14 can be equal to the thickness of the second conductive part 142.

[0519] t4-t1 can be the difference between the thickness of the conductive part 14 and the thickness of the conductive main part 13, to represent the thickening degree of the conductive part 14.

[0520] 0.2 μm≤t4-t1≤4.5 μm, it can be understood that the value of t4-t1 can be 0.2 μm, 4.5 μm, and any value between 0.2 μm and 4.5 μm; for example, the value of t4-t1 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 scheme of this embodiment, the design of 0.2 μm≤t4-t1≤4.5 μm, the difference between the maximum thickness of the conductive part 14 and the thickness of the conductive main part 13 is within a reasonable range, which can improve the overcurrent capacity at the conductive part 14, improve the fast charging performance and use reliability of the battery monomer 100, in addition, the thickness of the conductive part 14 is not too large, which is conducive to reducing the occupied space and weight of the conductive part 14, and is conducive to improving the energy density of the battery monomer 100.

[0522] In some embodiments, 0.3 μm≤t4-t1≤1.75 μm.

[0523] By adopting the technical scheme of this embodiment, the design of 0.3 μm≤t4-t1≤1.75 μm, the difference between the maximum thickness of the conductive part 14 and the thickness of the conductive main part 13 is within a more reasonable range, which can improve the overcurrent capacity at the conductive part 14, improve the fast charging performance and use reliability of the battery monomer 100, in addition, the thickness of the conductive part 14 is not too large, which is conducive to reducing the occupied space and weight of the conductive part 14, and is conducive to improving the energy density of the battery monomer 100.

[0524] In some embodiments, the thickness of the conductive main part 13 is t1, and the maximum thickness of the conductive part 14 is t4, wherein 1

[0525] t1 / t4 can be the ratio of the thickness of the conductive part 14 to the thickness of the conductive main part 13, and can also represent the thickening degree of the conductive part 14.

[0526] 1

[0527] By adopting the technical scheme of this embodiment, the design of 1 < t1 / t4 ≤ 4, the ratio of the maximum thickness of the conductive part 14 to the thickness of the conductive main part 13 is within a reasonable range, the overcurrent capacity at the conductive part 14 can be improved, the fast charging performance and use reliability of the battery monomer 100 are improved, 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 monomer 100.

[0528] In some embodiments, 1.5 < t1 / t4 ≤ 2.5.

[0529] By adopting the technical scheme of this embodiment, the design of 1.5 < t1 / t4 ≤ 2.5, the ratio of the maximum thickness of the conductive part 14 to the thickness of the conductive main part 13 is within a more reasonable range, the overcurrent capacity at the conductive part 14 can be improved, the fast charging performance and use reliability of the battery monomer 100 are improved, 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 monomer 100.

[0530] In some embodiments, the thickness of the conductive part 14 is t4, wherein 1 μm ≤ t4 ≤ 5 μm.

[0531] 1 μm ≤ t4 ≤ 5 μm, it can be understood that the value of t4 can be 1 μm, 5 μm and any value between 1 μm and 5 μm; for example, the value of t4 can be but not limited to 1 μm, 1.1 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 5 μm.

[0532] By adopting the technical scheme of this embodiment, the design of 1 μm ≤ t4 ≤ 5 μm, the thickness of the conductive part 14 is designed reasonably, the overcurrent capacity at the conductive part 14 can be improved, the fast charging performance and use reliability of the battery monomer 100 are improved, 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 monomer 100.

[0533] In some embodiments, 1.2 μm ≤ t4 ≤ 3.5 μm.

[0534] By adopting the technical scheme of this embodiment, the design of 1.2 μm ≤ t4 ≤ 3.5 μm, the thickness of the conductive part 14 is designed more reasonably, the overcurrent capacity at the conductive part 14 can be improved, the fast charging performance and use reliability of the battery monomer 100 are improved, 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 monomer 100.

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

[0536] The first body segment 143 can be a main part of the conductive portion 14, the first body segment 143 is generally of an equal-thickness structure, and the first transition segment 144 can be a part of the conductive portion 14 connected between the first body segment 143 and the conductive body portion 13; for example, the first body segment 143 can include the second conductive portion 142 and the second segment described above, and the first transition segment 144 can be the first segment described above.

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

[0538] By adopting the technical solutions of this embodiment, the first transition segment 144 can reduce stress concentration of the metal layer 12, reduce the risk of cracks in the metal layer 12 during forming, improve the overcurrent capacity of the conductive portion 14, and improve the fast-charging performance and use reliability of the battery monomer 100, and facilitate processing and manufacturing.

[0539] In some embodiments, the thickness of the first transition segment 144 increases in a direction from the conductive body portion 13 to the conductive portion 14.

[0540] In a direction from the conductive body portion 13 to the conductive portion 14, the thickness of the first transition segment 144 can increase in a stepped manner or slowly.

[0541] By adopting the technical solutions of this embodiment, the stress concentration of the metal layer 12 can be better reduced, the risk of cracks in the metal layer 12 during forming can be better reduced, the overcurrent capacity of the conductive portion 14 can be better improved, the fast-charging performance and use reliability of the battery monomer 100 can be better improved, and processing and manufacturing are facilitated.

[0542] In some embodiments, in the first direction, the size of the first transition segment 144 is W6, where 4mm≤W6≤50mm, and optionally, 5mm≤W6≤34mm.

[0543] The size W6 of the first transition segment 144 can refer to the width of the first transition segment 144.

[0544] 4mm≤W6≤50mm, it can be understood that the value of W6 can be 4mm, 50pm and any value between 4mm and 50pm; for example, the value of W6 can be but not limited to 4mm, 5mm, 8mm, 10mm, 20mm, 25mm, 30mm, 33mm, 34mm, 37mm, 40mm, 45mm, 50mm.

[0545] By adopting the technical scheme of this embodiment, the design of 4mm≤W6≤50mm, the size of the first transition section 144 in the first direction is reasonable, which can reduce the stress concentration of the metal layer 12, reduce the risk of cracks in the forming process of the metal layer 12, improve the overcurrent capacity of the conductive part 14, improve the fast charging performance and use reliability of the battery monomer 100, and also facilitate processing and manufacturing. In addition, the size of the first transition section 144 in the first direction is not too large, which reduces the space and weight occupied by the conductive part 14, and is beneficial to improve the energy density of the battery monomer 100.

[0546] In some embodiments, 5mm≤W6≤34mm.

[0547] By adopting the technical scheme of this embodiment, the design of 5mm≤W6≤34mm, the size of the first transition section 144 in the first direction is more reasonable, which can reduce the stress concentration of the metal layer 12, reduce the risk of cracks in the forming process of the metal layer 12, improve the overcurrent capacity of the conductive part 14, improve the fast charging performance and use reliability of the battery monomer 100, and also facilitate processing and manufacturing. In addition, the size of the first transition section 144 in the first direction is not too large, which reduces the space and weight occupied by the conductive part 14, and is beneficial to improve the energy density of the battery monomer 100.

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

[0549] The conductive protective layer 60 can refer to a conductive structure arranged between the active material layer 20 and the metal layer 12, which can conduct electricity, so that the battery monomer 100 can output or input electric energy.

[0550] Part of the conductive protective layer 60 is located between the active material layer 20 and the metal layer 12, and the other part covers the metal layer 12 and protrudes out of the active material layer 20; for example, part of the conductive protective layer 60 covers the conductive main part 13 and the first conductive part 141, and the other part of the conductive protective layer 60 covers the part of the second conductive part 142 close to the first conductive part 141.

[0551] For example, the conductive protective layer 60 can contain conductive carbon black and a binder, which 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 improve the performance of the battery monomer 100.

[0552] During the rolling process of the first pole piece 1, the thickness of the metal layer 12 is relatively thin, and the particles in the active material layer 20 can damage the metal layer 12, which can cause the metal layer 12 to easily crack and other problems. The conductive protective layer 60 of the embodiment of the application can separate the active material layer 20 and the metal layer 12, and can protect the metal layer 12, reduce the cracks generated during the rolling of the metal layer 12, and improve the overcurrent capacity of the metal layer 12.

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

[0554] The conductive protective layer 60 protrudes from the active material layer 20, which can completely separate the metal layer 12 and the active material layer 20, and can provide an extension space for the active material layer 20 during the rolling process, which is beneficial to the subsequent conductive protective layer 60 that can completely separate the metal layer 12 and the active material layer 20.

[0555] By adopting the technical scheme of the embodiment, the conductive protective layer 60 can completely separate the active material layer 20 and the metal layer 12, the protection of the metal layer 12 by the conductive protective layer 60 is better, the overcurrent capacity of the first pole piece 1 is better, and the fast-charging performance and use reliability of the battery monomer 100 are improved.

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

[0557] The protruding distance of the conductive protective layer 60 protruding from the end face of the active material layer 20 towards the protruding part 1421 is S3, wherein 0.3mm≤S3≤0.8mm, and the value of S3 can be 0.3mm, 0.8mm, and any value between 0.3mm and 0.8mm, for example: the value of S3 can be but not limited to 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm.

[0558] The design of S3≥0.3mm can make the conductive protective layer 60 completely separate the active material layer 20 and the metal layer 12, the conductive protective layer 60 has better protection ability for the metal layer 12, the overcurrent capacity of the first tab 1 is better, and the fast charging performance and use reliability of the battery monomer 100 are improved; the design of S3≤0.8mm makes the conductive protective layer 60 not too large and occupies space, which is beneficial to save the internal space of the battery monomer 100 and improve the energy density of the battery monomer 100.

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

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

[0561] In some examples, the conductive protective layer 60 is spaced apart from the first connecting part 31, and the first insulating part 41 covers the part of the conductive protective layer 60 between the first connecting part 31 and the active material layer 20.

[0562] By adopting the technical scheme of the embodiment, the first connecting part 31 will not be welded to the conductive protective layer 60, which can reduce the risk of false welding and the like, and is beneficial to improve the reliability of the welding of the first connecting part 31 and the metal layer 12.

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

[0564] The first protective part 61 can be the part of the conductive protective layer covering the conductive main part 13, and the second protective part 62 can be the part of the conductive protective layer covering the conductive part 14, wherein the second protective part 62 can cover part of the conductive part 14 or cover the entire conductive part 14.

[0565] By adopting the technical scheme of the embodiment, the thickness of the second protective part 62 is less than the thickness of the first protective part 61, which is beneficial to reduce the sum of the thickness of the first protective part 61 and the thickness of the conductive main part 13 close to the sum of the thickness of the second protective part 62 and the thickness of the conductive part 14, which is beneficial to make the surface of the conductive protective layer away from the metal layer 12 close to a plane, thereby reducing the roll pressing damage and improving the overcurrent capacity of the metal layer 12; in addition, the winding bulging problem of the current collector 10 can also be reduced.

[0566] In some embodiments, the conductive part 14 includes a first main section 143 and a first transition section 144 connected between the first main section 143 and the conductive main part 13, the first transition section 144 has a thickness greater than that of the conductive main part 13; the first main section 143 has a thickness greater than that of the first transition section 144; the second protective part 62 includes a second main section 621 and a second transition section 622, the second transition section 622 covers the first transition section 144, and the second main section 621 covers at least part of the first main section 143; the second transition section 622 has a thickness less than that of the first protective part 61; the second main section 621 has a thickness less than that of the second transition section 622.

[0567] The second protective part 62 is divided into two sections according to the segmented conductive main section and the first transition section 144 of the conductive part 14, one section covering the first main section 143 is the second main section 621, and one section covering the first transition section 144 is the second transition section 622, wherein the second main section 621 can cover part of the first main section 143 or the entire first main section 143.

[0568] The second transition section 622 has a thickness less than that of the first protective part 61; the second main section 621 has a thickness less than that of the second transition section 622, so that the second main section 621 and the second transition section 622 can compensate for the thickness difference between the first main section 143 and the first transition section 144, thereby facilitating the surface of the second protective part 62 opposite to the metal layer 12 to be close to a plane.

[0569] For example, the first protective part 61 and the conductive main part 13 are generally equal-thickness structures, the shape of the first protective part 61 is adapted to the shape of the conductive main part 13, the shape of the second main section 621 is adapted to the shape of the first main section 143, the second main section 621 is also a generally equal-thickness structure, and the shape of the second transition section 622 is adapted to the shape of the first transition section 144, so that the thickness difference of the conductive part 14 can be better adapted.

[0570] By adopting the technical scheme of this embodiment, the thickness change of the second protective part 62 can compensate for the thickness change of the conductive part 14, which is conducive to the surface of the second protective part 62 opposite to the metal layer 12 to be close to a plane, and is conducive to reducing the roll pressure damage and improving the current-carrying capacity of the metal layer 12; in addition, the winding bulging problem of the current collector 10 can also be reduced.

[0571] In some embodiments, in the direction of the conductive main part 13 pointing to the conductive part 14, the thickness of the first transition section 144 is arranged to increase, and the thickness of the second transition section 622 is arranged to decrease.

[0572] In the direction of the conductive main body part 13 pointing to the conductive part 14, the thickness of the first transition section 144 is stepped up, the thickness of the corresponding second transition section 622 is stepped down, and the absolute values of the thickness change amplitudes of the two are the same or close to each other. In the direction of the conductive main body part 13 pointing to the conductive part 14, the thickness of the first transition section 144 is slowly increased, the thickness of the corresponding second transition section 622 is slowly decreased, and the absolute values of the thickness change amplitudes of the two are the same or close to each other.

[0573] By adopting the technical solutions of this embodiment, the thickness change of the second protection part 62 is adapted to the thickness of the conductive part 14, the thickness change of the second protection part 62 better compensates for the thickness change of the conductive part 14, which is more conducive to the surface of the second protection part 62 facing away from the metal layer 12 being close to a plane, reducing the roll damage and improving the current-carrying capacity of the metal layer 12; in addition, it can also reduce the winding bulging problem of the current collector 10.

[0574] In some embodiments, the thickness of the second main body section 621 is t5, and the thickness of the first protection part 61 is t6, where 0.03≤t5 / t6≤0.95.

[0575] t5 / t6 can refer to the ratio of the thickness of the second main body section 621 to the thickness of the first protection part 61, which can represent the thinning degree of the second main body section 621 relative to the first protection part 61.

[0576] 0.03≤t5 / t6≤0.95, it can be understood that the value of t5 / t6 can be 0.03, 0.95, and any value between 0.03 and 0.95; for example, the value of t5 / t6 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 solutions of this embodiment, the design of 0.03≤t5 / t6≤0.95, the thinning degree of the conductive protection layer 60 is reasonable, which can better adapt to the thickening degree of the conductive part 14, which is conducive to the surface of the second protection part 62 facing away from the metal layer 12 being close to a plane, reducing the roll damage and improving the current-carrying capacity of the metal layer 12.

[0578] In some embodiments, 0.125≤t5 / t6≤0.8.

[0579] By adopting the technical solutions of this embodiment, the design of 0.03≤t5 / t6≤0.95, the thinning degree of the conductive protection layer 60 is more reasonable, which can better adapt to the thickening degree of the conductive part 14, which is conducive to the surface of the second protection part 62 facing away from the metal layer 12 being close to a plane, reducing the roll damage and improving the current-carrying capacity of the metal layer 12.

[0580] In some embodiments, the thickness of the second body segment 621 is t5, where 0.5 μm≤t5≤4 μm.

[0581] 0.5 μm≤t5≤4 μm, and it can be understood that t5 can be 0.5 μm, 4 μm, and any value between 0.5 μm and 4 μm; for example, t5 can be, but is not limited to, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm.

[0582] By adopting the technical scheme of this embodiment, the setting of 0.5 μm≤t5≤4 μm makes the second body segment 621 have a certain thickness, thereby reducing the risk of cracking of the metal layer 12; in addition, the second body segment 621 will not protrude out of the first protective portion 61 in the direction away from the metal layer 12 due to being too thick, and material accumulation can also be reduced, thereby reducing the manufacturing cost.

[0583] In some embodiments, 1 μm≤t5≤2 μm.

[0584] By adopting the technical scheme of this embodiment, the setting of 1 μm≤t5≤2 μm makes the second body segment 621 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 portion 111 and a second insulating base portion 112, the conductive body portion 13 is covered on the first insulating base portion 111, and the conductive portion 14 is covered on the second insulating base portion 112; the thickness of the conductive body portion 13 is t1, the thickness of the conductive portion 14 is t4, the thickness of the first protective portion 61 is t6, the minimum thickness of the second protective portion 62 is t7, the thickness of the first insulating base portion 111 is t8, and the thickness of the second insulating base portion 112 is t9, where -4 μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4 μm.

[0586] The insulating base 11 is divided into two parts, where the part covered with the conductive body portion 13 is the first insulating base portion 111, and the part covered with the conductive portion 14 is the second insulating base portion 112; the insulating base 11 can be generally of an equal thickness structure, where the thickness t8 of the first insulating base portion 111 is equal to the thickness t9 of the second insulating base portion 112. The insulating base 11 can also be of a stepped structure, where the thickness t8 of the first insulating base portion 111 is greater than or less than the thickness t9 of the second insulating base portion 112.

[0587] The second protection part 62 is generally an equal-thickness structure, the minimum thickness t7 of the second protection part 62 is equal to the thickness of the second protection part 62; in the direction of the conductive main body part 13 pointing to the conductive part 14, the thickness of the second protection part 62 gradually decreases, the minimum thickness t7 of the second protection part 62 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 t7 of the second protection part 62 is equal to the thickness t5 of the second main body segment 621.

[0588] t1+t6+t8 / 2, which can refer to half the thickness of the current collector 10 at the conductive main body part 13; t4+t7+t9 / 2, which can refer to half the thickness of the current collector 10 at the conductive part 14.

[0589] -4μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4μm, it can be understood that the value of (t1+t6+t8 / 2)-(t4+t7+t9 / 2) can be -4μm, 4μm, and any value between -4μm and 4μm; for example, the value of t5 can be but not limited to -4μm, -3μm, -2μm, -1μm, 0μm, 1μm, 2μm, 3μm, 4μm.

[0590] By adopting the technical scheme of this embodiment, the design of -4μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4μm makes the half thickness of the current collector 10 at the conductive main body part 13 and the half thickness of the current collector 10 at the conductive part 14 have little difference, which is beneficial to the surface of the conductive protection layer 60 away from the metal layer 12 to have a nearly planar surface, is beneficial to reducing the roll pressure damage and improving the flow capacity of the metal layer 12; in addition, it can also reduce the drum edge of the electrode assembly 101.

[0591] In some embodiments, -2μm≤(t1+t6+t8 / 2)-(t2+t7+t8 / 2)≤2μm.

[0592] By adopting the technical scheme of this embodiment, the design of -2μm≤(t1+t6+t8 / 2)-(t2+t7+t8 / 2)≤2μm makes the half thickness of the current collector 10 at the conductive main body part 13 and the half thickness of the current collector 10 at the conductive part 14 closer, which is more beneficial to the surface of the conductive protection layer 60 away from the metal layer 12 to have a nearly planar surface, is beneficial to reducing the roll pressure damage and improving the flow 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 scheme of the embodiment, the thickness of the second insulating base 112 is less than the thickness of the first insulating base 111, so that the sum of the thickness of the second insulating base 112 and the thickness of the conductive part 14 is close to the sum of the thickness of the first insulating base 111 and the thickness of the conductive main body part 13, which is beneficial to the surface of the metal layer 12 being close to a plane in the back direction of the insulating base 11, and is beneficial to reducing roll damage and improving the overcurrent capacity of the metal layer 12.

[0595] In some embodiments, referring to FIG. 3, the shell 200 includes a shell body 202 and an end cover 201, the end cover 201 is arranged at the opening of the shell body 202, and the shell body 202 and the end cover 201 form a containing cavity, the electrode assembly 101 is contained in the containing cavity, and at least one of the shell body 202 and the end cover 201 is provided with an electrode lead-out part 2011.

[0596] The electrode lead-out part 2011 can be arranged on the shell body 202 or the end cover 201, or both the end cover 201 and the shell body 202 are provided with the electrode lead-out part 2011.

[0597] By adopting the technical scheme of the embodiment, the shell 200 adopts the structure of the end cover 201 and the shell body 202, the electrode assembly 101 is easy to be assembled into the shell 200, the assembly of the battery monomer 100 is facilitated, and the manufacturing cost is reduced.

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

[0599] The capacity of the battery monomer 100 is one of important performance indicators for measuring the performance of the battery monomer 100, which represents the amount of electricity discharged by the battery device 1100 under certain conditions (discharge rate, temperature, terminal voltage, etc.), that is, the capacity of the battery monomer 100, which is usually measured in ampere-hours (abbreviated as A·h, 1A·h=3600C). For example, the capacity of the battery monomer 100 can be directly read from the identification element of the battery monomer 100.

[0600] The capacity of the battery monomer 100 is greater than or equal to 20A·h, the capacity of the battery monomer 100 is high, and the overcurrent capacity and use reliability of the electrode plate in the battery monomer 100 are better, and the battery monomer 100 of the embodiment of the application can better meet the use requirement that the capacity of the battery monomer 100 is greater than or equal to 20A·h by adopting the thickened structure of the conductive part 14.

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

[0602] The active material layer 20 adds the Ni element, so that the energy density of the battery monomer 100 is improved. When the burr of the current collector 10 pierces the diaphragm and contacts the negative electrode sheet, the battery monomer 100 is prone to thermal runaway due to the high energy density of the battery monomer 100.

[0603] By adopting the technical scheme of the embodiment, the active material of the active material layer 20 contains the Ni element, so that the energy density of the battery monomer 100 is improved. In addition, the positive electrode sheet adopts the structure of the first electrode sheet 1, and the current collector 10 of the first electrode sheet 1 adopts the structure of the composite current collector 10, so that the risk of internal short circuit of the battery monomer 100 is reduced, and the risk of thermal runaway of the battery monomer 100 is reduced.

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

[0605] By adopting the technical scheme of the embodiment, the metal layer 12 adopts the above-mentioned material, which is conducive to improving the performance of the battery monomer 100.

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

[0607] Embodiment one

[0608] In the present embodiment, referring to FIGS. 3-10, the battery monomer 100 includes an end cover 201, a shell 202, and an electrode assembly 101. The electrode assembly 101 is installed at the shell 202, the end cover 201 covers the opening of the shell 202 to seal the shell 202, and the electrode assembly 101 includes a first electrode sheet 1, a second electrode sheet 2, and a separator 3. The separator 3 is located between the first electrode sheet 1 and the second electrode sheet 2, and the polarities of the first electrode sheet 1 and the second electrode sheet 2 are opposite. The first electrode sheet 1 can be a positive electrode sheet, and the second electrode sheet 2 can be a negative electrode sheet. Alternatively, the first electrode sheet 1 can be a negative electrode sheet, and the second electrode sheet 2 can be a positive electrode sheet.

[0609] In the present embodiment, the end cover 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 base body 11 and a metal layer 12, the insulating base body 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 part of the metal layer 12 is located between the insulating base body 11 and the active material layer 20. 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, and the thickness of the conductive portion 14 is greater than the thickness of the conductive main body portion 13.

[0610] In the present embodiment, the conductive member 30 includes a first connecting portion 31 and a second connecting portion 32, the first connecting portion 31 is connected between the second connecting portion 32 and the conductive main portion 13, the first connecting portion 31 includes a first connecting sub-portion 311 and a second connecting sub-portion 312, the first connecting sub-portion 311 is connected between the second connecting sub-portion 312 and the conductive main portion 13, the first connecting sub-portion 311 and the second connecting sub-portion 312 are partially covered by the first active material portion 21 and the second active material portion 22.

[0611] In the present embodiment, the second connecting portion 32 includes a transition portion 322 and a plurality of protruding portions 321 arranged along the second direction, the transition portion 322 is connected between the protruding portions 321 and the first connecting sub-portion 311, the protruding portions 321 include a first protruding sub-portion 3211 and a second protruding sub-portion 3212, the first protruding sub-portion 3211 is connected between the second protruding sub-portion 3212 and the transition portion 322, along the second direction, the size of the first protruding sub-portion 3211 is greater than the size of the second protruding sub-portion 3212.

[0612] The first connecting portion 31 of the conductive member 30 is welded on the first protruding sub-portion 3211 to form a first welding mark portion 511, the second connecting portion 32 of the conductive member 30 is welded on the electrode lead-out portion 2011, and the first welding mark portion 511 forms a first welding mark 51.

[0613] In the present embodiment, the electrode assembly 101 further includes an insulating member 40, the insulating member 40 includes a first insulating portion 41, the first insulating portion 41 covers the end portion of the second protruding sub-portion 3212 close to the active material layer 20 and the transition portion 322.

[0614] Embodiment Two

[0615] The difference between this embodiment and Embodiment One is that, referring to FIGS. 11-17, the first connecting portion 31 of the conductive member 30 is welded on the surface of the protruding portion 321 away from the insulating substrate 11 to form a first welding mark portion 511, the second connecting portion 32 of the conductive member 30 is welded on the transition portion 322 to form a second welding mark portion 512, and the second welding mark portion 512 and the first welding mark portion 511 jointly form a first welding mark 51.

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

[0617] Embodiment Three

[0618] The embodiment differs from the embodiment two in that, referring to FIGS. 18-21, the insulating member 40 comprises a second insulating portion 42, one side of the second insulating portion 42 covers the first solder print 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 FIG. 2, a battery device 1100 is provided, comprising the battery cell 100 of the above embodiments.

[0620] The battery device 1100 of the embodiments of the present application adopts the battery cell 100 described above, and the battery cell 100 has good fast charging performance and use reliability, which is conducive to improving the fast charging performance and use reliability of the battery device 1100, and also conducive to improving the use reliability of the battery device 1100.

[0621] In some embodiments, referring to FIG. 1, a power consumption device is provided, comprising the battery device 1100 of the above embodiments.

[0622] The power consumption device of the embodiments of the present application adopts the battery device 1100 described above, and the battery device 1100 has good fast charging performance and use reliability, which is conducive to improving the endurance of the power consumption device, and also conducive to improving the use reliability of the power consumption device.

[0623] The above description of the various embodiments tends to emphasize the differences between the various embodiments, and the same or similar parts can be referred to each other, and for brevity, will not be repeated here.

[0624] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the above embodiments, or make equivalent replacement to part 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 be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature 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 falling within the scope of the claims.

Claims

A battery cell, wherein, The application relates to a battery, comprising: a housing provided with an electrode lead-out portion; an electrode assembly at least partially arranged in the housing; the electrode assembly comprises a first electrode tab, the first electrode tab comprises a current collector and an active material layer, the current collector comprises an insulating base body and a metal layer, the insulating base body, the metal layer and the active material layer are arranged in a stacking mode along the thickness direction of the current collector, and at least part of the metal layer is located between the insulating base body and the active material layer; wherein the metal layer comprises a conductive main body portion and a conductive portion extending from the conductive main body portion 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 portion is covered with the active material layer, at least part of the conductive portion is not covered with the active material layer, and the conductive portion is connected with 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. The battery cell of claim 1, wherein: the surface of the conductive portion away from the insulating base body is farther away from the insulating base body than the surface of the conductive main body portion away from the insulating base body. The battery cell according to claim 1 or 2, wherein: the conductive portion comprises a first conductive portion and a second conductive portion arranged along the first direction, the first conductive portion is connected between the second conductive portion and the conductive main body portion, the first conductive portion is covered with the active material layer, the second conductive portion is not covered with the active material layer, and the second conductive portion is connected with the electrode lead-out portion. The battery cell of claim 3, wherein: the active material layer comprises a first active material portion and a second active material portion arranged along the first direction, the first active material portion is connected with the second active material portion, the thickness of the first active material portion is less than the thickness of the second active material portion, at least part of the first active material portion is covered on the first conductive portion, and at least part of the second active material portion is covered on the conductive main body portion. The battery cell of claim 4, wherein: the surface of the first active material portion away from the insulating base body is closer to the insulating base body than the surface of the second active material portion away from the insulating base body. The battery cell according to claim 4 or 5, wherein: the second active material portion covers part of the first conductive portion, and the first active material portion covers other part of the first conductive portion. The battery cell of claim 6, wherein: along the first direction, the size of the part of the first conductive portion covered by the second active material portion is W1, the size of the part of the first conductive portion covered by the first active material portion is W2, and W1>=W2. The battery cell according to any one of claims 4 to 7, wherein: the thickness of the conductive main 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. The battery cell of claim 8, wherein: 60mu m<=t3<=250mu m; optionally, 80mu m<=t3<=180mu m. The battery cell according to any one of claims 3 to 9, wherein: along the first direction, the size of the first conductive portion is W3, and the size of the conductive portion is W4, wherein W3 / W4<=0.

4. The battery cell according to any one of claims 3 to 10, wherein: along the first direction, the size of the first conductive portion is W3, and the size of the conductive portion is W4, wherein 2mm<=W4-W3<=10mm, and optionally, 3mm<=W4-W3<=6mm. The battery cell according to any one of claims 3 to 11, wherein: In the first direction, the first conductive part has a size W3, and the conductive main part has a size W5, wherein W3 / (W3+W5)≤0.

45. The battery cell according to any one of claims 3 to 12, wherein: In the first direction, the first conductive part has a size W3, wherein 10mm≤W3≤100mm. The battery cell according to any one of claims 3 to 13, wherein: The second conductive part comprises at least one protruding part connected to the first conductive part, and in a second direction, the size of the protruding part is smaller than the size of the conductive main part, and the second direction is perpendicular to the thickness direction of the current collector and the first direction. The battery cell of claim 14, wherein: The protruding part comprises a first protruding subpart and a second protruding subpart, and the first protruding subpart is connected between the second protruding subpart and the first conductive part; in the second direction, the size of the first protruding subpart is larger than the size of the second protruding subpart. The battery cell according to claim 14 or 15, wherein: The number of the protruding parts is multiple, and the multiple protruding parts are arranged at intervals in the second direction, and in the second direction, the sum of the sizes of all the protruding parts is smaller than the size of the conductive main part. The battery cell according to any one of claims 14 to 16, wherein: The second conductive part further comprises a transition part connected between the protruding part and the first conductive part, and in the second direction, the size of the transition part is larger than the sum of the sizes of all the protruding parts. In the second direction, the size of the conductive main part is L1, and the size of the transition part is L2, wherein 0.8≤L2 / L1≤1. The battery cell of claim 17, wherein: The first pole piece further comprises a conductive member comprising a first connecting part and a second connecting part arranged in the first direction, the first connecting part is connected to the second connecting part, the first connecting part is connected to the surface of the second conductive part away from the insulating base, the second connecting part is located at the side of the second conductive part away from the first conductive part, and the second connecting part is connected to the electrode lead-out part. The battery cell according to any one of claims 3 to 18, wherein: In the first direction, the first connecting part is arranged at intervals with the active material layer. The battery cell of claim 19, wherein: The first connecting part is welded to the surface of the second conductive part away from the insulating base and forms a first welding mark. The battery cell of claim 20, wherein: The second conductive part comprises at least one protruding part connected to the first conductive part, and in a second direction, the size of the protruding part is smaller than the size of the conductive main part; The battery cell of claim 21, wherein: The second direction is perpendicular to the thickness direction of the current collector and the first direction; The first welding mark comprises a first welding mark part, and the first connecting part is welded to the surface of the protruding part away from the insulating base and forms the first welding mark part. The protruding part comprises a first protruding subpart and a second protruding subpart, and the first protruding subpart is connected between the second protruding subpart and the first conductive part; in the second direction, the size of the first protruding subpart is larger than the size of the second protruding subpart. The battery cell of claim 22, wherein: The first welding mark part comprises a first welding mark subpart, and the first connecting part is welded to the first protruding subpart and forms the first welding mark subpart; And / or, the first welding mark part further comprises a second welding mark subpart, and the first connecting part is welded to the surface of the second protruding subpart away from the insulating base and forms the second welding mark subpart. ​ The battery cell of claim 22 or 23, wherein: The number of the protrusions is plural, and the plural protrusions are arranged at intervals along the second direction; The first connecting part includes plural first connecting sub-parts arranged at intervals along the second direction, and the number of the second connecting parts is plural, each first connecting sub-part being connected to each second connecting part one by one; Each first connecting sub-part is welded to the surface of each protrusion away from the insulating base one by one. The battery cell according to any one of claims 21 to 24, wherein: The second conductive part includes a transition part and at least one protrusion, the transition part being connected between the first conductive part and the protrusion, along the second direction, the size of the transition part being greater than the sum of the sizes of all the protrusions; the second direction being perpendicular to the thickness direction of the current collector and the first direction; The first welding mark further includes a second welding mark part, and the first connecting part is welded to the surface of the transition part away from the insulating base and forms the second welding mark part. The battery cell of claim 25, wherein: Along the second direction, the size of the transition part is L2, the size of the second welding mark part is L3, and 0.8≤L3 / L2≤1. The battery cell of claim 25 or 26, wherein: The number of the protrusions is plural, and the plural protrusions are arranged at intervals along the second direction; The first connecting part includes a second connecting sub-part and plural first connecting sub-parts arranged at intervals along the second direction, each first connecting sub-part covering each protrusion one by one; The number of the second connecting parts is plural, along the first direction, one side of each first connecting sub-part being connected to each second connecting part one by one, and the other side of each first connecting sub-part being connected to the second connecting sub-part, the second connecting sub-part being arranged continuously along the second direction; The second connecting sub-part is welded to the surface of the transition part away from the insulating base. The battery cell according to any one of claims 21 to 27, wherein: The electrode assembly further includes an insulating piece, the insulating piece including a first insulating part covering the surface of the second conductive part away from the insulating base, the entire first insulating part being located between the first welding mark and the active material layer. The battery cell of claim 28, wherein: The first insulating part is located between the first connecting part and the active material layer. The insulating piece further includes a second insulating part, at least part of the second insulating part covering the first welding mark. The battery cell of claim 29, wherein: Along the first direction, one side of the second insulating part covers the first welding mark, and the other side of the second insulating part covers at least part of the first insulating part. The battery cell of claim 30, wherein: The electrode assembly further includes an insulating piece, the insulating piece including a second insulating part, at least part of the second insulating part covering the first welding mark. The battery cell according to any one of claims 21 to 31, wherein: Along the first direction, one side of the second insulating part covers the first welding mark, and the other side of the second insulating part covers at least part of the active material layer. The battery cell of claim 32, wherein: The number of the metal layers is two, the two metal layers being arranged on opposite sides of the insulating base along the thickness direction of the current collector, and the number of the active material layers is two, the two active material layers covering the two metal layers respectively; The battery cell according to any one of claims 30 to 33, wherein: ​ The number of the conductive members is two, and the first connecting portions of the two conductive members are respectively welded to the second conductive portions of the two metal layers and form two first welding marks; The number of the 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. The battery cell of claim 34, wherein: The second insulating portion comprises a first portion and a second portion connected to each other, the first portion covers the first welding mark, and the second portion protrudes from the side of the second conductive portion along the direction in which the conductive main body portion points to the conductive portion. The battery cell of claim 35, wherein: The second portions of the two insulating members are in abutment. The battery cell according to any one of claims 34 to 36, wherein: The second connecting portions of the two conductive members are welded and form a second welding mark. The battery cell of claim 37, wherein: The second insulating portion covers the second welding mark along the direction in which the conductive main body portion points to the conductive portion, and the second insulating portion protrudes from the edge of the second welding mark away from the conductive main body portion. The battery cell according to any one of claims 28 to 38, wherein: The electrode assembly comprises a second tab opposite in polarity to the first tab, the second tab comprises a main functional portion and a tab portion, the tab portion protrudes from the main functional portion along the first direction; along the direction in which the conductive main body portion points to the conductive portion, the main functional portion protrudes from the end surface of the insulating member towards 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. The battery cell according to any one of claims 28 to 39, wherein: Along the first direction, the size of the portion of the insulating member covering the active material layer is H, wherein 0.2mm≤H≤1.0mm, and optionally, 0.3mm≤H≤0.8mm. The battery cell according to any one of claims 21 to 40, wherein: Along the first direction, the distance between the first welding mark and the active material layer is S1, wherein 0.5mm≤S1≤5mm, and optionally, 0.5mm≤S1≤2.8mm. The battery cell according to any one of claims 21 to 41, wherein: Along the first direction, the distance between the end surface of the first welding mark and the first connecting portion towards the active material layer is S2, wherein 0.3mm≤S2≤1.2mm. The battery cell according to any one of claims 1 to 42, wherein: The electrode assembly comprises a second tab opposite in polarity to the first tab, the second tab comprises a main functional portion and a tab portion, the tab portion protrudes from the main functional portion along the first direction; Along the direction in which the conductive main body portion points to the conductive portion, the main functional portion protrudes from the end surface of the conductive portion away from the conductive main body portion. The battery cell according to any one of claims 1 to 43, wherein: 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; and optionally, 0.05≤W4 / W5≤0.

6. The battery cell according to any one of claims 1 to 44, wherein: The thickness of the conductive main body portion is t1, and the maximum thickness of the conductive portion is t4, wherein 0.2μm≤t4-t1≤4.5μm, and optionally, 0.3μm≤t4-t1≤1.75μm. The battery cell according to any one of claims 1 to 45, wherein: The thickness of the conductive main body portion is t1, and the maximum thickness of the conductive portion is t4, wherein 1 The thickness of the conductive main body portion is t1, and the maximum thickness of the conductive portion is t4, wherein 1 The battery cell of claim 46, wherein: The thickness of the conductive part is t4, wherein 1 μm≤t4≤5 μm, and optionally, 1.2 μm≤t4≤3.5 μm. The battery cell according to any one of claims 1 to 47, wherein: The conductive part comprises a first main section and a first transition section, the first transition section is connected between the first main section and the conductive main part, the thickness of the first transition section is greater than the thickness of the conductive main part; the thickness of the first main section is greater than the thickness of the first transition section; at least part of the first transition section is covered with the active material layer. The battery cell of claim 48, wherein: The thickness of the first transition section is arranged in an increasing manner in the direction of the conductive main part pointing to the conductive part. The battery cell of claim 48 or 49, wherein: In the first direction, the size of the first transition section is W6, wherein 4 mm≤W6≤50 mm, and optionally, 5 mm≤W6≤34 mm. The battery cell according to any one of claims 1 to 50, wherein: The first pole piece further comprises a conductive protective layer, at least part of the conductive protective layer is located between the active material layer and the metal layer. The battery cell of claim 51, wherein: In the direction of the conductive main part pointing to the conductive part, the protruding distance range of the conductive protective layer protruding from the active material layer towards the end face of the protruding part is 0.3 mm-0.8 mm. The battery cell of claim 51 or 52, wherein: The conductive protective layer comprises a first protective part and a second protective part, the first protective part covers the conductive main 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. The battery cell of claim 53, wherein: The conductive part comprises a first main section and a first transition section, the first transition section is connected between the first main section and the conductive main part, the thickness of the first transition section is greater than the thickness of the conductive main part; the thickness of the first main section is greater than the thickness of the first transition section; The second protective part comprises a second main section and a second transition section, the second transition section covers the first transition section, and 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 protective part; the thickness of the second main section is less than the thickness of the second transition section. The battery cell of claim 54, wherein: In the direction of the conductive main part pointing to the conductive part, the thickness of the first transition section is arranged in an increasing manner, and the thickness of the second transition section is arranged in a decreasing manner. The battery cell of claim 54 or 55, wherein: The thickness of the second main section is t5, and the thickness of the first protective part is t6, wherein 0.03≤t5 / t6≤0.95, and optionally, 0.125≤t5 / t6≤0.

8. The battery cell of any one of claims 54-56, wherein: The thickness of the second main section is t5, wherein 0.5 μm≤t5≤4 μm, and optionally, 1 μm≤t5≤2 μm. The battery cell of any one of claims 53-57, wherein: The insulating base includes a first insulating base and a second insulating base, the conductive main body part is covered on the first insulating base, and the conductive part is covered on the second insulating base; the thickness of the conductive main body part 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 -4 μm≤(t1+t6+t8 / 2)-(t4+t7+t9 / 2)≤4 μm, and optionally, -2 μm≤(t1+t6+t8 / 2)-(t2+t7+t8 / 2)≤2 μm. The battery cell of claim 58, wherein: The thickness of the second insulating base is less than the thickness of the first insulating base. The battery cell according to any one of claims 1 to 59, wherein: The shell includes a shell body and an end cover, the end cover is arranged at an opening of the shell body, the shell body and the end cover form a containing cavity, the electrode assembly is contained in the containing cavity, and at least one of the shell body and the end cover is provided with the electrode lead-out part. The battery cell according to any one of claims 1 to 60, wherein: The capacity of the battery monomer is greater than or equal to 20 A·h. The battery cell according to any one of claims 1 to 61, wherein: The first electrode tab is a positive electrode tab, and the active material of the active material layer contains an element Ni. The battery cell of any one of claims 1-62, wherein: The material of the metal layer includes one or more of aluminum, an aluminum alloy, copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy. A battery device, wherein: The battery monomer includes any one of claims 1-63. An electric power utilization device, wherein: The battery device includes claim 64. The battery monomer includes any one of claims 1-63.

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