Battery cell, battery device, and electrical device

Abstract

A battery cell (100), a battery device (1100), and an electrical device. 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). The electrode assembly (101) is at least partially accommodated in the housing (200). The electrode assembly (101) comprises a first electrode plate (1). The first electrode plate (1) comprises a conductive member (30), a current collector (10), and an active material layer (20). The conductive member (30) is connected to the electrode lead-out portion (2011). 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 a thickness direction of the current collector (10). At least part of the metal layer (12) is located between the insulating substrate (11) and the active material layer (20). The metal layer (12) comprises a conductive portion (121) and an extension portion (122) extending outward from an end portion of the conductive portion (121) in a first direction, the first direction being perpendicular to the thickness direction of the current collector (10). The conductive portion (121) is covered with the active material layer (20), while the extension portion (122) is not covered with the active material layer (20). The conductive member (30) is welded to a surface of the extension portion (122) facing away from the insulating substrate (11) and forms a first weld mark (51). A spacing between the first weld mark (51) and the active material layer (20) ranges from 0.3 mm to 5 mm.

Description

Battery cell, battery device and electric device TECHNICAL FIELD

[0001] The present application belongs to the technical field of battery energy density, 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 electric capacity use requirements; however, in the technology of battery cells, how to improve the energy density 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 can improve the energy density of the battery cell, but not limited thereto.

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

[0008] In some embodiments, a battery cell is provided. The battery cell includes a housing and an electrode assembly. The housing is provided with an electrode lead-out portion. The electrode assembly is at least partially accommodated in the housing. The electrode assembly includes a first electrode tab. The first electrode tab includes a conductive member, a current collector and an active material layer. The conductive member is connected to the electrode lead-out portion. The current collector includes an insulating base and a metal layer. The insulating base, the metal layer and the active material layer are stacked along the thickness direction of the current collector. At least part of the metal layer is located between the insulating base and the active material layer. The metal layer includes a conductive portion and an extension portion extending outward from the end of the conductive portion in a first direction. The first direction is perpendicular to the thickness direction of the current collector. The conductive portion is covered with the active material layer, and the extension portion is not covered with the active material layer. The conductive member is welded to the surface of the extension portion away from the insulating base and forms a first welding mark. The spacing between the first welding mark and the active material layer ranges from 0.3mm to 5mm.

[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, and charging and discharging of the battery monomer are realized; the interval between the first welding mark and the active material layer is designed to be 0.3mm-5mm, so that the first welding mark will not be welded to the active material layer, and problems such as false welding are reduced, which is beneficial to improving the connection reliability of the conductive member and the metal layer; the interval between the active material layer and the first welding mark is small, and the active material layer can be relatively close to the first welding mark, so that in the case of a certain size of the metal layer in the first direction, the active material layer can cover a larger area, which is beneficial to improving the energy density of the battery monomer; in addition, the current collector adopts the composite structure of the insulating substrate 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 energy density and the use reliability.

[0010] In some embodiments, the interval between the first welding mark and the active material layer is 0.5mm-2.8mm.

[0011] By adopting the technical scheme of the embodiment, the distance between the active material layer and the first welding mark is more reasonable, and the connection reliability of the conductive member and the energy density of the battery monomer can be better balanced.

[0012] In some embodiments, the conductive member includes a first connecting part and at least one second connecting part, the first connecting part and the second connecting part are arranged along the first direction, the first connecting part and the second connecting part are connected, the second connecting part is connected with the electrode lead-out part, the first connecting part is welded to the surface of the extension part away from the insulating substrate and forms the first welding mark, and the second connecting part is located at the side of the extension part away from the conductive part.

[0013] By adopting the technical scheme of the embodiment, the second connecting part protrudes out of the extension part, so that the second connecting part can be conveniently connected with the electrode lead-out part, and the processing and manufacturing are more convenient.

[0014] In some embodiments, along the first direction, the first welding mark is arranged at an interval away from the end surface of the first connecting part towards the active material layer.

[0015] By adopting the technical scheme of the embodiment, the first welding mark will not extend to the end surface of the first connecting part towards the active material layer, the risk of being welded through or cracked at the end surface of the first connecting part towards the active material layer is reduced, burrs generated by welding are reduced, and the use reliability of the battery monomer is improved.

[0016] In some embodiments, along the first direction, the interval between the first welding mark and the end surface of the first connecting part towards the active material layer is 0.3mm-1.2mm.

[0017] By adopting the technical solutions of the embodiment, the use reliability and energy density of the battery monomer can be well balanced.

[0018] In some embodiments, the first welding mark includes a first welding mark part, the extension part includes at least one protruding part, the protruding part is connected with the conductive 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; in the second direction, the size of the protruding part is smaller than the size of the conductive part, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0019] By adopting the technical solutions of the embodiment, the first connecting part and the protruding part are connected by welding, which is simple and convenient for the manufacturing of the first pole piece; in addition, the first connecting part and the protruding part can directly flow through the first welding mark part, which is conducive to improving the flow capacity between the first connecting part and the protruding part; in addition, in the second direction, the size of the protruding part is smaller than the size of the conductive part, the protruding part is easy to be bent with the conductive member to be connected with the electrode lead-out part, which is convenient for processing and manufacturing, and is also conducive to reducing the space occupied by the protruding part after being bent, and is conducive to improving the energy density of the battery monomer.

[0020] In some embodiments, in the second direction, the first welding mark part extends from one side of the protruding part to the other side of the protruding part.

[0021] By adopting the technical solutions of the embodiment, in the second direction, the first welding mark part can occupy the entire protruding part, the size of the first welding mark part in the second direction is large, which is conducive to improving the flow area between the first connecting part and the protruding part, improving the flow capacity between the first connecting part and the protruding part, reducing the risk of heating, and improving the fast-charging performance and use reliability of the battery monomer.

[0022] In some embodiments, the protruding part includes a first protruding subpart and a second protruding subpart, the second protruding subpart is connected between the conductive part and the first protruding subpart; in the second direction, the size of the second protruding subpart is smaller than the size of the first protruding subpart, and the size of the first protruding subpart is smaller than the size of the conductive part; the first welding mark part includes a first welding subpart; the first connecting part is welded to the surface of the first protruding subpart away from the insulating base and forms the first welding subpart.

[0023] By adopting the technical solutions of the embodiment, the first connecting part and the first protruding subpart are welded and form the first welding part, the size of the first protruding subpart in the second direction is large, which is conducive to improving the welding area of the protruding part and the first connecting part, improving the flow area between the protruding part and the conductive part, improving the flow capacity, reducing the heat generation of the battery monomer, and improving the fast-charging performance and use reliability of the battery monomer; in addition, in the second direction, the size of the first protruding subpart is small, which is conducive to reducing the space occupied by the protruding part and improving the energy density of the battery monomer.

[0024] In some embodiments, the first welding sub-portion extends from one side edge of the first protruding sub-portion to another side edge of the first protruding sub-portion along the second direction.

[0025] By adopting the technical scheme of this embodiment, the size of the first welding sub-portion along the second direction is large, which is conducive to increasing the welding area between the protruding portion and the first connecting portion, increasing the flow area between the protruding portion and the conductive portion, and improving the flow capacity, thereby reducing the heat generation of the battery monomer and improving the fast charging performance and use reliability of the battery monomer.

[0026] In some embodiments, the first welding portion further comprises a second welding sub-portion, and the first connecting portion is welded to the surface of the second protruding sub-portion away from the insulating base and forms the second welding sub-portion.

[0027] By adopting the technical scheme of this embodiment, the second protruding sub-portion is also welded to the first connecting portion, which is conducive to increasing the flow area between the first connecting portion and the protruding portion and improving the flow capacity between the first connecting portion and the protruding portion.

[0028] In some embodiments, the second welding sub-portion extends from one side edge of the second protruding sub-portion to another side edge of the second protruding sub-portion along the second direction.

[0029] By adopting the technical scheme of this embodiment, the size of the second welding sub-portion along the second direction is large, which is conducive to increasing the welding area between the first connecting portion and the protruding portion, increasing the flow area between the first connecting portion and the protruding portion, and improving the flow capacity between the first connecting portion and the protruding portion.

[0030] In some embodiments, the number of the protruding portions is multiple, and the multiple protruding portions are arranged at intervals along the second direction, and each protruding portion is welded to the first connecting portion.

[0031] By adopting the technical scheme of this embodiment, the multiple protruding portions are arranged at intervals along the second direction, which is conducive to dividing the conductive portion into multiple regions along the second direction, and one region can correspond to one protruding portion, and the electrons in each region can be transmitted to the electrode lead-out portion through the corresponding protruding portion, so that the electrons of the conductive portion are transmitted in a region-by-region manner, the transmission path of the electrons in each region is short, which is conducive to reducing the transmission distance of the electrons and reducing the overall resistance of the first electrode sheet, thereby improving the fast charging performance and use reliability of the battery monomer.

[0032] In some embodiments, the first connecting part comprises a plurality of first connecting sub-parts, the plurality of first connecting sub-parts are arranged at intervals along the second direction, the number of the second connecting parts is plural, each first connecting sub-part is connected to each second connecting part in one-to-one correspondence; each first connecting sub-part is welded to the surface of each protruding part away from the insulating base in one-to-one correspondence; each first connecting sub-part is welded to the surface of each protruding part away from the insulating base in one-to-one correspondence.

[0033] By adopting the technical scheme of this embodiment, the plurality of first connecting sub-parts of the first connecting part are arranged at intervals along the second direction, and there is a gap between the adjacent two first connecting sub-parts, which can reduce the required material of the first connecting part and reduce the manufacturing cost of the battery monomer.

[0034] In some embodiments, the first welding mark comprises a second welding mark part, the extending part further comprises a transition part, the transition part is connected between the protruding part and the conductive part, 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; along the second direction, the size of the transition part is greater than the sum of the sizes of all the protruding parts.

[0035] By adopting the technical scheme of this embodiment, the surface of the transition part away from the insulating base is welded to the first connecting part, so that a part of the current can flow directly into or out of the first connecting part through the transition part, reducing the flow pressure between the protruding part and the transition part, which is conducive to reducing the heat generation at the connection between the protruding part and the transition part; in addition, the first connecting part and the transition part are connected by welding, which is simple and convenient for the manufacturing of the first pole piece; the first connecting part and the transition part can directly utilize the second welding mark part for flow, which is conducive to improving the flow capacity between the first connecting part and the transition part and reducing the heat generation of the battery monomer.

[0036] In some embodiments, along the second direction, the size of the conductive part is L1, the size of the transition part is L2, and 0.8≤L2 / L1≤1.

[0037] By adopting the technical scheme of this embodiment, the size of the transition part along the second direction is large, which is conducive to improving the connection area between the first connecting part and the transition part, improving the flow capacity at the connection between the first connecting part and the transition part, improving the flow capacity of the first pole piece, reducing the heat generation of the battery monomer, and improving the fast charging performance of the battery monomer.

[0038] 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.

[0039] By adopting the technical scheme of the embodiment, the size of the second welding portion in the second direction is large, which is beneficial to increase the connection area between the first connection portion and the transition portion, improve the current-carrying capacity at the connection between the first connection portion and the transition portion, improve the current-carrying capacity of the first pole piece, reduce the heat generation of the battery monomer, and improve the fast-charging performance of the battery monomer.

[0040] In some embodiments, the number of protrusions is a plurality, and the plurality of protrusions are arranged at intervals in a second direction perpendicular to the first direction and the thickness direction of the current collector; the first connection portion includes a second connection sub-portion and a plurality of first connection sub-portions, the plurality of first connection sub-portions are arranged at intervals in the second direction, and each first connection sub-portion is welded to the surface of each protrusion away from the insulating base one by one; the number of second connection portions is a plurality, and in the first direction, one side of each first connection sub-portion is connected to each second connection portion one by one, and the other side of each first connection sub-portion is connected to the second connection sub-portion, and the second connection sub-portion is arranged continuously in the second direction; and the second connection sub-portion is welded to the surface of the transition portion away from the insulating base.

[0041] By adopting the technical scheme of the embodiment, the second connection sub-portion is arranged continuously in the second direction, which can connect the plurality of first connection sub-portions into one whole, the second connection sub-portion can provide good support to the first connection sub-portion, which can reduce the risk of the first connection sub-portion bending and being inserted between the first pole piece and the second pole piece, reduce the risk of short circuit, and be beneficial to improve the use reliability of the battery monomer; in addition, in the second direction, the size of the second connection sub-portion is large, which is beneficial to increase the welding area between the second connection sub-portion and the transition portion, is beneficial to improve the current-carrying capacity at the connection between the first connection portion and the transition portion, is beneficial to improve the current-carrying capacity of the first pole piece, and is beneficial to improve the fast-charging performance and use reliability of the battery monomer.

[0042] In some embodiments, in the first direction, the first connection portion and the active material layer are arranged at intervals.

[0043] By adopting the technical scheme of the embodiment, the first connection portion does not contact the active material layer, which can reduce the mutual influence between the two and improve the use reliability of the battery monomer.

[0044] In some embodiments, the electrode assembly further includes an insulating piece, and the insulating piece includes a first insulating portion covering the surface of the extension portion away from the insulating base, and the entire first insulating portion is located between the first welding mark and the active material layer.

[0045] By adopting the technical scheme of the embodiment, it is beneficial to reduce the risk of virtual welding between the first connection portion and the extension portion, is beneficial to reduce the risk of virtual welding between the first connection portion and the extension portion, improve the connection reliability of the first connection portion and the extension portion, and is also beneficial to improve the current-carrying capacity.

[0046] In some embodiments, the first insulation portion is located between the first connecting portion and the active material layer.

[0047] By adopting the technical scheme of this embodiment, the first insulation portion can support the part of the extension portion between the first connecting portion and the active material layer, and can reduce damage such as cracks and breakage of this part during the manufacturing process of the battery device, thereby facilitating improvement of the electronic transmission capability of this part and improvement of the fast-charging performance and use reliability of the battery monomer. In addition, the first insulation portion can also achieve insulation of this part, thereby reducing the short circuit risk of the battery monomer and improving the use reliability of the battery monomer.

[0048] In some embodiments, the insulation piece further comprises a second insulation portion, at least part of the second insulation portion covering the first welding mark.

[0049] By adopting the technical scheme of this embodiment, the second insulation portion can block the sharp end protrusion on the surface of the first welding mark and metal debris and the like from piercing the isolation piece to connect with the second pole piece, thereby reducing the short circuit risk of the battery monomer and improving the use reliability of the battery monomer.

[0050] In some embodiments, along the first direction, one side of the second insulation portion covers the first welding mark, and the other side of the second insulation portion covers at least part of the first insulation portion.

[0051] By adopting the technical scheme of this embodiment, the second insulation portion and the first insulation portion jointly cover the extension portion, which can achieve double-layer insulation, thereby facilitating reduction of the short circuit risk of the battery monomer and improvement of the use reliability of the battery monomer.

[0052] In some embodiments, the electrode assembly further comprises an insulation piece, the insulation piece comprising a second insulation portion, at least part of the second insulation portion covering the first welding mark.

[0053] By adopting the technical scheme of this embodiment, the second insulation portion covers the surface of the first welding mark, which can block the sharp end protrusion on the surface of the first welding mark and metal debris and the like from piercing the isolation piece to connect with the second pole piece, thereby reducing the short circuit risk of the battery monomer and improving the use reliability of the battery monomer.

[0054] In some embodiments, along the first direction, one side of the second insulation portion covers the first welding mark, and the other side of the second insulation portion covers at least part of the first insulation portion.

[0055] By adopting the technical scheme of this embodiment, the second insulation portion extends from the first welding mark to the active material layer, the second insulation portion has a wide coverage area and good insulation effect, thereby facilitating improvement of the use reliability of the battery monomer.

[0056] 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, and the two active material layers respectively cover the two metal layers; the number of conductive members is two, the first connecting portions of the two conductive members are respectively welded to the surfaces of the two metal layers away from the insulating base and form two first welding marks; and the number of insulating members is two, the second insulating portions of the two insulating members respectively cover at least part of the two first welding marks.

[0057] By adopting the technical scheme of this embodiment, the first connecting portions of the two conductive members are respectively welded to the metal layers located on opposite sides of the insulating base, and the second connecting portions of the two conductive members are located on the side portions of the extension portions away from the conductive portions, so that the two metal layers can be directly connected by the second connecting portions 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.

[0058] In some embodiments, the second insulating portion includes a first portion and a second portion connected to each other, the first portion covers at least part of the first welding mark, and the second portion protrudes from the extension portion along the direction of the conductive portion toward the extension portion, and the second portion is located on the side portion of the second connecting portion along the second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

[0059] By adopting the technical scheme of this embodiment, along the direction of the conductive portion pointing to the extension portion, the metal debris and other components at the end surface of the extension portion away from the active material layer can be located between the second portions of the two insulating members, so that the risk of the metal debris falling into the electrode assembly can be reduced, and the risk of short circuit can be reduced.

[0060] In some embodiments, the second portions of the two insulating members are in abutment.

[0061] By adopting the technical scheme of this embodiment, after the second portions of the two insulating members are in abutment, the metal debris and other components at the end surface of the extension portion away from the active material layer 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.

[0062] In some embodiments, the second connecting portions of the two conductive members are welded and form a second welding mark.

[0063] By adopting the technical scheme of this embodiment, the second connecting portions of the two conductive members are directly welded, on the one hand, the metal layers located on opposite sides of the insulating base can be connected, 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 of the battery monomer, and improving the use reliability of the battery monomer; on the other hand, the welding operation is simple and convenient for processing and manufacturing.

[0064] In some embodiments, the second insulating part covers the second welding mark and protrudes from the edge of the second welding mark away from the conductive part in the direction of the extension part.

[0065] By adopting the technical scheme of this embodiment, the second insulating part can completely cover the second welding mark, block the sharp protrusions, metal debris and other components on the second welding mark from piercing the isolation member to connect with the second tab, reduce the risk of short circuit, and improve the use reliability of the battery monomer.

[0066] In some embodiments, the electrode assembly includes a second tab opposite in polarity to the first tab, the second tab including a main functional part and a tab part, the tab part protruding from the main functional part in a first direction; in the direction of the conductive part towards the extension part, the main functional part protrudes from the end surface of the insulating member towards the active material layer, and the main functional part does not protrude from the end surface of the insulating member away from the active material layer.

[0067] By adopting the technical scheme of this embodiment, the insulating member can block the burrs at the end surface of the main functional part of the second tab close to the tab part from piercing the isolation member 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.

[0068] In some embodiments, the electrode assembly includes a second tab opposite in polarity to the first tab, the second tab including a main functional part and a tab part, the tab part protruding from the main functional part in a first direction; in the direction of the conductive part towards the extension part, the main functional part protrudes from the end surface of the extension part away from the conductive part.

[0069] By adopting the technical scheme of this embodiment, the burrs at the end surface of the main functional part of the second tab towards the tab part correspond to the hollow area of the metal layer that does not extend out of the second connecting part, which can also reduce the risk of short circuit of the battery monomer and improve the use reliability of the battery monomer.

[0070] In some embodiments, the current collector further includes a conductive protective layer, at least part of the conductive protective layer being located between the active material layer and the conductive part.

[0071] By adopting the technical scheme of this embodiment, the conductive protective layer can separate the active material layer and the metal layer while protecting the metal layer, reducing the risk of cracks in the metal layer caused by rolling the active material layer, and being conducive to improving the current-carrying capacity of the metal layer.

[0072] In some embodiments, in the direction of the conductive part towards the extension part, the conductive protective layer protrudes from the end surface of the active material layer close to the extension part.

[0073] By adopting the technical scheme of the embodiment, the conductive protective layer can completely separate the active material layer and the metal layer, the conductive protective layer has better protection capability for the metal layer, the overcurrent capability of the first tab is better, and the fast charging performance and the use reliability of the battery monomer are improved.

[0074] In some embodiments, the protruding distance range of the conductive protective layer protruding from the end face of the active material layer towards the extension part in the direction of the conductive part towards the extension part is 0.3mm-0.8mm.

[0075] By adopting the technical scheme of the embodiment, the overcurrent capability and the energy density of the battery monomer can be better balanced.

[0076] In some embodiments, the conductive protective layer and the first welding mark are arranged apart in the first direction.

[0077] By adopting the technical scheme of the embodiment, the first connecting part will not be welded to the conductive protective layer, which can reduce the risk of false welding and the like, and the reliability of the welding of the first connecting part to the metal layer is improved.

[0078] In some embodiments, the thickness of the conductive part is less than the thickness of the extension part.

[0079] By adopting the technical scheme of the embodiment, the thickness of the extension part is large, the overcurrent capability of the extension part is good, the overcurrent capability of the first tab is improved, the heat generation of the battery monomer is reduced, the fast charging performance and the use reliability of the battery monomer are improved.

[0080] In some embodiments, the conductive part includes a first sub-part and a second sub-part, the first sub-part is connected between the second sub-part and the extension part, the first sub-part and the second sub-part are covered with the active material layer, the thickness of the first sub-part is greater than the thickness of the second sub-part, and the thickness of the extension part is greater than or equal to the thickness of the first sub-part.

[0081] By adopting the technical scheme of the embodiment, the overcurrent capability of the first sub-part close to the transition part is greater than the overcurrent capability of the second sub-part away from the transition part, which can reduce the limitation of the current, improve the overcurrent capability of the first tab, reduce the heat generation of the battery monomer, and improve the use reliability of the battery monomer.

[0082] In some embodiments, the current collector further includes a conductive protective layer, the conductive protective layer includes a first protective part and a second protective part, the first protective part is located between the first sub-part and the active material layer, and the second protective part is located between the second sub-part and the active material layer, wherein the thickness of the first protective part is less than the thickness of the second protective part.

[0083] By adopting the technical scheme of the embodiment, the surface of the conductive protective layer away from the surface of the insulating base approaches a plane, which is beneficial to reduce roll damage and improve the overcurrent capacity of the metal layer; in addition, the winding bulging problem of the current collector can also be reduced.

[0084] In some embodiments, the conductive protective layer further comprises a third protective portion, the third protective portion covering the surface of the extension portion away from the surface of the insulating base, and the thickness of the third protective portion is less than or equal to the thickness of the first protective portion.

[0085] By adopting the technical aspect of the embodiment, the third protective portion is provided, so that the conductive protective layer protrudes from the active material layer, so that the active material layer and the metal layer can be better separated, in addition, the thickness of the third protective portion is not too large, which is beneficial to reduce the waste of materials and save the manufacturing cost of the battery monomer.

[0086] In a second aspect, a battery device is provided, comprising the battery monomer of the above-mentioned embodiments.

[0087] The battery device of the embodiments of the present application adopts the above-mentioned battery monomer, and the energy density of the battery monomer is large, so the energy density of the battery device is large.

[0088] In a third aspect, a power consumption device is provided, comprising the battery device of the above-mentioned embodiments.

[0089] The power consumption device of the embodiments of the present application adopts the above-mentioned battery device, and the energy density of the battery monomer is large, which is beneficial to improve the endurance and use performance of the power consumption device.

[0090] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and to be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0091] In order to more clearly illustrate the technical scheme in the embodiments of the present 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 present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0092] Fig. 1 is a structural schematic view of a vehicle provided by some embodiments of the present application.

[0093] Fig. 2 is an exploded schematic view of a battery device provided by some embodiments of the present application.

[0094] Fig. 3 is an exploded schematic view of a battery monomer provided by some embodiments of the present application.

[0095] FIG. 4 is a structural schematic view of an electrode assembly according to some embodiments of the present application.

[0096] FIG. 5 is a sectional view along line A-A of FIG. 4.

[0097] FIG. 6 is a structural schematic view of a first tab according to some embodiments of the present application.

[0098] FIG. 7 is a sectional view along line B-B of FIG. 6.

[0099] FIG. 8 is an enlarged view of a portion of FIG. 6 at C.

[0100] FIG. 9 is a structural schematic view of the first tab according to some embodiments of the present application, with a conductive member hidden.

[0101] FIG. 10 is an enlarged view of a portion of FIG. 9 at D.

[0102] FIG. 11 is a structural schematic view of a first tab according to other embodiments of the present application.

[0103] FIG. 12 is an enlarged view of a portion of FIG. 11 at E.

[0104] FIG. 13 is a structural schematic view of the first tab according to other embodiments of the present application, with a conductive member hidden.

[0105] FIG. 14 is an enlarged view of a portion of FIG. 13 at F.

[0106] FIG. 15 is a structural schematic view of a first tab according to still other embodiments of the present application.

[0107] FIG. 16 is a sectional view along line H-H of FIG. 15.

[0108] FIG. 17 is a sectional view along line I-I of FIG. 15.

[0109] FIG. 18 is a structural schematic view of a first tab according to still other embodiments of the present application.

[0110] FIG. 19 is an enlarged view of a portion of FIG. 18 at J.

[0111] FIG. 20 is a structural schematic view of a first tab according to still other embodiments of the present application.

[0112] FIG. 21 is a sectional view along line K-K of FIG. 20.

[0113] FIG. 22 is a structural schematic view of a second insulating portion according to some embodiments of the present application.

[0114] FIG. 23 is a sectional view along line N-N of FIG. 22.

[0115] 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; 12, metal layer; 121, conductive portion; 1211, first sub-portion; 1212, second sub-portion; 122, extension portion; 1221, transition portion; 1222, protruding portion; 12221, first protruding sub-portion; 12222, second protruding sub-portion; 13, conductive protective layer; 131, first protective portion; 132, second protective portion; 133, third protective portion; 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 weld mark; 511, first weld mark portion; 5111, first weld mark sub-portion; 5112, second weld mark sub-portion; 512, second weld mark portion; 52, second weld mark; 2, second tab; 210, main body functional portion; 220, tab portion; 3, separator; 200, housing; 201, end cap; 2011, electrode lead-out portion; 202, case; 300, box body; 301, first box body portion; 302, second box body portion. DETAILED DESCRIPTION

[0116] 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 with reference to 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.

[0117] 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.

[0118] In the description of the embodiments of the present application, the technical terms "first", "second", etc. 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.

[0119] In the description of the embodiments of the present application, the term "and / or" is merely an 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 " / " in this paper generally represents that the front and rear associated objects are an "or" relationship.

[0120] 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.

[0121] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "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 a limitation on the embodiments of the present application.

[0122] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "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.

[0123] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0124] 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 of the battery cell.

[0125] 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, and the like.

[0126] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, or other shaped battery cell, the prismatic battery cell including a square-shaped battery cell, a blade-shaped battery cell, a multi-prismatic battery cell, such as a hexagonal prismatic battery cell, and the like.

[0127] The battery device referred to in embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0128] In some embodiments, the battery device can be a battery module, when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0129] In some embodiments, the battery device can be a battery pack, the battery pack including a box and battery cells, the battery cells or battery modules being contained in the box.

[0130] 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 longitudinal beam of the vehicle.

[0131] 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, and the like.

[0132] The battery cell generally includes an electrode assembly and a case, the electrode assembly being contained in the case. The electrode assembly includes a positive electrode and a negative electrode. During 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.

[0133] In some embodiments, the electrode assembly further includes a separator, the separator being disposed between the positive electrode and the negative electrode, and can prevent the positive electrode and the negative electrode from short-circuiting while allowing the active ions to pass through.

[0134] The case is used to encapsulate the electrode assembly and other components such as electrolyte. The case can be a steel case, an aluminum case, a plastic case (such as polypropylene), a composite metal case (such as a copper-aluminum composite case), or an aluminum-plastic film, and the like.

[0135] In some embodiments, the positive electrode can be a positive electrode sheet, the positive electrode sheet 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, the negative electrode sheet 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.

[0136] 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 penetrate the separator to cause internal short circuit, which causes a high risk of fire and explosion of the battery cell.

[0137] 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 set to be small, so that the burr generated by the metal layer during the penetration of the foreign matter into the pole piece is small and not easy to penetrate the separator. However, the capacity of the active material layer covering the surface of the metal layer is small, which is not conducive to improving the energy density of the battery cell.

[0138] Therefore, the embodiments of the present application provide a technical scheme, the conductive member of the battery cell and the extension part of the conductive part are welded to form a first welding mark, and the spacing range between the first welding mark and the active material layer is 0.3mm-5mm. The spacing range is small, so that the active material layer is relatively close to the first welding mark, which is equivalent to increasing the coverage area of the active material layer on the metal layer, which is conducive to improving the energy density of the battery cell.

[0139] The battery cell described in the embodiments of the present application is suitable for a battery device and a power consumption device using the battery device.

[0140] The battery device disclosed in the embodiments of the present application can be used in a power consumption device using the battery device as a power supply 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 computer, a notebook computer, an electric toy, a power tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric plane toys, etc. The spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0141] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0142] As shown in FIG. 1, the inside of the vehicle 1000 is provided with a battery device 1100, which can be arranged at the bottom, head or 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 supply of the vehicle 1000.

[0143] The vehicle 1000 can further include a controller 1200 and a motor 1300, the controller 1200 being configured to control the battery device 1100 to supply power to the motor 1300, for example, for power requirements of the vehicle 1000 during start-up, navigation, and travel.

[0144] In some embodiments of the present application, the battery device 1100 can not only serve as a power source for the operation of the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000. FIG. 2 is an exploded view of the battery device 1100 according to some embodiments of the present application. As shown in FIG. 2, the battery device 1100 includes a box 300 and a battery cell 100, the battery cell 100 being accommodated in the box 300.

[0145] The box 300 is configured to accommodate the battery cell 100, and the box 300 can have 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 being coupled to each other to 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 can be a plate structure, the first box part 301 being coupled to the open end of the second box part 302 to form the box 300 with the accommodation space. Alternatively, the first box part 301 and the second box part 302 can each be a hollow structure with one side open, the open side of the first box part 301 being coupled to 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 have various shapes, such as a cylinder or a cuboid.

[0146] To improve the sealing performance of the first box part 301 and the second box part 302 after being coupled, a sealing member, such as a sealant or a sealing ring, can be provided between the first box part 301 and the second box part 302.

[0147] Suppose the first box part 301 is coupled to the top of the second box part 302, the first box part 301 can also be referred to as an upper box cover, and the second box part 302 can also be referred to as a lower box.

[0148] In the battery device 1100, the battery cell 100 can be one or a plurality of battery cells. If the battery cell 100 is a plurality of battery cells, the plurality of battery cells 100 can be connected in series, in parallel, or in a mixed connection, the mixed connection referring to a connection in which some of the plurality of battery cells 100 are connected in series and some of the plurality of battery cells 100 are connected in parallel.

[0149] The plurality of battery cells 100 can be directly connected in series or in parallel or in a mixed manner, and the plurality of battery cells 100 can be accommodated in the case 300. Of course, the plurality of battery cells 100 can be connected in series or in parallel or in a mixed manner to form a battery module, and the plurality of battery modules can be connected in series or in parallel or in a mixed manner to form a whole and can be accommodated in the case 300.

[0150] Exemplarily, the battery cell 100 can be the smallest unit of the battery device 1100.

[0151] 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 charging and discharging of the battery cell 100, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode and the negative electrode. Optionally, the electrode assembly 101 further includes a separator 3 disposed 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, can allow the active ions to pass through.

[0152] The housing 200 is used to encapsulate the electrode assembly 101 and other components such as electrolyte.

[0153] In some embodiments, the housing 200 includes a shell 202 and an end cover 201, the shell 202 has an opening, and the end cover 201 is used to cover the opening.

[0154] The shell 202 is a component used to cooperate with the end cover 201 to form an internal cavity of the battery cell 100, and the internal cavity can be used to accommodate the electrode assembly 101, the electrolyte, and other components.

[0155] The shell 202 and the end cover 201 can be independent components. Exemplarily, an opening can be provided on the shell 202, and the internal cavity of the battery cell 100 can be formed by covering the opening with the end cover 201.

[0156] The shell 202 can be various shapes and various sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell 202 can be determined according to the specific shape and size of the electrode assembly 101. The material of the shell 202 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, aluminum plastic film, steel plastic film, etc.

[0157] The shape of the end cover 201 can be adapted to the shape of the shell 202 to fit the shell 202. The material of the end cover 201 can be the same as or different from the material of the shell 202. Optionally, the end cover 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 cover 201 is not easily deformed when subjected to extrusion and collision, and the battery monomer 100 can have higher structural strength and improved reliability.

[0158] The end cover 201 is connected to the shell 202 by welding, bonding, clamping, or other means.

[0159] The shell 202 can be open at one end or both ends. In some examples, the shell 202 can be a structure open on one side, and the end cover 201 is provided as one and covers the shell 202. In other examples, the shell 202 can also be a structure open on both sides, and the end cover 201 is provided as two, and the two end covers 201 cover the two openings of the shell 202, respectively.

[0160] In some embodiments, the battery monomer 100 includes electrode lead-out portions 2011. The number of electrode lead-out portions 2011 is two, and the two electrode lead-out portions 2011 are connected to the positive and negative electrode sheets, respectively, for outputting or inputting the electrical energy of the battery monomer 100.

[0161] In some embodiments, the battery monomer 100 further includes an electrolyte contained in the shell 200. The electrolyte plays a role of conducting ions between the positive and negative electrodes. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0162] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0163] 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 difluoroboric oxalate, lithium boric oxalate, lithium difluorophosphoric oxalate, and lithium tetrafluorophosphoric oxalate.

[0164] 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, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0165] The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0166] In some embodiments, the gel-state electrolyte includes a polymer as a backbone network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0167] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, a composite solid-state electrolyte.

[0168] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, cellulose, or the like.

[0169] As an example, the inorganic solid-state electrolyte can be one or more of an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfur, argyrodite), amorphous sulfide), and a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0170] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0171] Referring to FIGS. 4 and 5, the electrode assembly 101 of the present embodiment includes first and second polar plates 1 and 2 having opposite polarities.

[0172] As an example, one of the first and second polar plates 1 and 2 is a positive polar plate, and the other is a negative polar plate.

[0173] In some embodiments, the positive polar plate can include a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector.

[0174] 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 or both of the two opposite surfaces of the positive current collector.

[0175] As an example, the positive electrode 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 polymer 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 polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0176] As an example, the positive electrode active material layer includes a positive electrode active material, which can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. The positive electrode active material can also use other conventional materials that can be used as the positive electrode active material layer of the battery device 1100. These positive electrode 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), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to simply as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to simply as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be referred to simply as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2), and a modified compound thereof, etc.

[0177] In some embodiments, the negative electrode sheet 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.

[0178] As an example, the negative electrode current collector can employ a metal foil, a foamed 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 foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed 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 (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0179] 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 for a battery cell 100 known in the art. 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 a battery device 1100. These negative electrode active materials can be used alone only one or two or more can be used in combination.

[0180] 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.

[0181] In some embodiments, the electrode assembly 101 further includes a separator 3 for separating the first electrode sheet 1 and the second electrode sheet 2. The separator 3 can reduce the risk of positive and negative electrode short circuit while allowing active ions to pass through.

[0182] In some embodiments, the separator 3 includes a separator film. The separator film of the present application can be selected from any known porous structure separator film having good chemical stability and mechanical stability.

[0183] As an example, the main material of the separator film can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, ceramic. 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 respective 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.

[0184] 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 electrode and the negative electrode.

[0185] In some embodiments, the electrode assembly 101 is in a jelly-roll structure. For example, the first electrode sheet 1 and the second electrode sheet 2 are each in a strip shape, and the first electrode sheet 1, the separator 3, and the second electrode sheet 2 are wound to form the jelly-roll structure.

[0186] In some embodiments, the electrode assembly 101 is in a stack structure.

[0187] For example, a plurality of first electrode sheets 1 and a plurality of second electrode sheets 2 are alternately stacked.

[0188] For example, a plurality of first electrode sheets 1 are provided, and the second electrode sheet 2 is folded to form a plurality of folded segments that are stacked.

[0189] For example, a plurality of first electrode sheets 1 and a plurality of second electrode sheets 2 are alternately stacked.

[0190] For example, a plurality of separators 3 are provided, and each of the separators 3 is disposed between any adjacent first electrode sheet 1 or second electrode sheet 2.

[0191] For example, the separators 3 are continuously provided, and are disposed between any adjacent first electrode sheet 1 or second electrode sheet 2 by folding or winding.

[0192] In some embodiments, the electrode assembly 101 can have a cylindrical shape, a flat shape, or a polygonal shape.

[0193] 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; the electrode assembly 101 is at least partially accommodated in the housing 200, the electrode assembly 101 comprises a first electrode tab 1, the first electrode tab 1 comprises a conductive member 30, a current collector 10 and an active material layer 20, the conductive member 30 is connected with the electrode lead-out portion 2011; the current collector 10 comprises 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, 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 comprises a conductive portion 121 and an extension portion 122 extending outward from the end of the conductive portion 121 along a first direction, the first direction is perpendicular to the thickness direction of the current collector 10; the conductive portion 121 is covered with the active material layer 20, the extension portion 122 is not covered with the active material layer 20; the conductive member 30 is welded to the surface of the extension portion 122 away from the insulating base body 11 and forms a first welding mark 51, the spacing between the first welding mark 51 and the active material layer 20 ranges from 0.3mm to 5mm.

[0194] 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.

[0195] 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 is a negative current collector, the negative current collector is a composite current collector structure, and the active material layer 20 is a negative active material layer.

[0196] The conductive member 30 can refer to a component for connecting the electrode lead-out portion 2011 and the current collector 10, the conductive member 30 can adopt a copper foil or an aluminum foil to facilitate connection with the electrode lead-out portion 2011.

[0197] The electrode lead-out portion 2011 can refer to a conductive component for outputting or inputting electric energy, the electrode lead-out portion 2011 is connected with an external electronic device to enable the battery cell 100 to output or input electric energy; the electrode lead-out portion 2011 can also be called a pole, the electrode lead-out portion 2011 can be provided on the shell 202 or on the end cover 201.

[0198] The electrode lead-out portion 2011 is connected with the conductive member 30, and the electrode lead-out portion 2011 can be directly connected with the conductive member 30; for example, the electrode lead-out portion 2011 is directly welded on the conductive member 30; or, the electrode lead-out portion 2011 can be connected with the conductive member 30 through a conductive piece (for example, a adapter sheet, etc.), for example, one end of the conductive piece is welded on the conductive member 30, and the other end of the conductive piece is welded on the electrode lead-out portion 2011.

[0199] The current collector 10 includes a metal layer 12 and an insulating base body 11, the current collector 10 is a multi-layer structure, the insulating base body 11 can refer to a component made of an insulating material (for example, the above-mentioned high molecular base material) in the current collector 10, and the metal layer 12 can refer to a component made of the above-mentioned metal material in the current collector 10.

[0200] The surface of the insulating base body 11 is covered with the metal layer 12, and the surface of the metal layer 12 away from the insulating base body 11 is covered with the active material layer 20, so that the insulating base body 11, the metal layer 12 and the active material layer 20 are stacked, and the stacking direction of the insulating base body 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.

[0201] In some examples, one surface of the insulating base body 11 is covered with the metal layer 12.

[0202] In some examples, the opposite two surfaces of the insulating base body 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 away from the surface of the insulating base body.

[0203] The first direction can be perpendicular to the thickness direction of the current collector 10; the second direction can be perpendicular to the thickness direction of the current collector 10 and the first direction.

[0204] In some examples, the electrode assembly 101 is a winding structure, when the first electrode sheet 1 is in an unfolded state, the first direction can refer to the width direction of the first electrode sheet 1 (see Z direction in FIG. 6); the second direction can refer to the length direction of the first electrode sheet 1 (see X direction in FIG. 6). When the first electrode sheet 1 is in a winding state, the second direction can also refer to the winding direction of the first electrode sheet 1 (see the direction indicated by the arrow V in FIG. 4).

[0205] In some examples, the electrode assembly 101 is a laminated structure, the first direction can be the width direction of the first electrode sheet 1 (see Z direction in FIG. 6), and the second direction can refer to the length direction of the first electrode sheet 1 (see X direction in FIG. 6).

[0206] In the first direction, the metal layer 12 is divided into two parts, the part covered with the active material layer 20 is the conductive part 121, and the part not covered with the active material layer 20 is the extension part 122. The conductive part 121 is of equal width structure, and the extension part 122 can also be of equal width structure with the conductive part 121, or can be of protruding structure arranged on one side of the conductive part 121, or other structures.

[0207] In some examples, the conductive member 30 and the electrode lead-out part 2011 can be connected by welding or conductive glue, etc.

[0208] In some examples, the conductive member 30 is welded to the surface of the extension part 122 away from the insulating substrate 11, and the area of the surface of the extension part 122 away from the insulating substrate 11 is large, which is beneficial to increase the welding area between the conductive member 30 and the extension part 122, improve the flow area between the conductive member 30 and the extension part 122, and improve the flow capacity of the first tab 1 and the fast-charging performance of the battery monomer 100.

[0209] The trace formed by welding the conductive member 30 to the surface of the extension part 122 away from the insulating substrate 11 is the first welding mark 51, and the first welding mark 51 is located on the side of the active material layer 20 in the first direction. In the first direction, the first welding mark 51 is arranged away from the active material layer 20, so that the part of the metal layer 12 not covered with the active material layer 20 is welded with the conductive member 30, and the conductive member 30 will not be welded to the active material layer 20, which is beneficial to reduce the risk of false welding and other problems, and improve the connection reliability and flow capacity of the metal layer 12 and the conductive member 30.

[0210] In the first direction, the distance between the first welding mark 51 and the active material layer 20 is S1, wherein 0.3mm≤S1≤5mm.

[0211] The design of S1≥0.3mm makes the first welding mark 51 and the active material layer 20 have a distance, so that the conductive member 30 will not be welded to the active material layer 20, reducing the risk of false welding and other problems; 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 beneficial to improve the coverage area of the active material layer 20 on the metal layer 12 and improve the energy density of the battery monomer 100.

[0212] 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 not limited to 0.3mm, 0.5mm, 1mm, 2mm, 2.5mm, 2.8mm, 3mm, 4mm, 5mm.

[0213] By adopting the technical scheme of the embodiment, in the case of normal use of the battery monomer 100, the electrode lead-out part 2011 is used for inputting or outputting electric energy, realizing charging and discharging of the battery monomer 100; the design that the spacing between the first welding mark 51 and the active material layer 20 is in the range of 0.3mm-5mm makes the first welding mark 51 not welded to the active material layer 20, reduces the problems such as false welding, and is beneficial to improving the connection reliability of the conductive member 30 and the metal layer 12; the spacing between the active material layer 20 and the first welding mark 51 is small, the active material layer 20 can be relatively close to the first welding mark 51, so that in the case that the size of the metal layer 12 in the first direction is certain, the active material layer 20 can cover a larger area, which is beneficial to improving the energy density 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, the thickness of the metal layer 12 is small compared with the pure metal current collector 10, the burr generated in the manufacturing process of the current collector 10 is small, 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 application can better balance the energy density and the use reliability.

[0214] In some embodiments, as shown in FIG. 7, the active material layer 20 includes a first active material part 21 and a second active material part 22, the first active material part 21 and the second active material part 22 are connected towards the end of the extension part 122, and the thickness of the first active material part 21 is less than the thickness of the second active material part 22.

[0215] In some examples, the first active material part 21 is located at the edge of the active material layer 20 towards the extension part 122, the first active material part 21 and the second active material part 22 are both covered on the conductive part 121, the first active material part 21 can be substantially an equal-thickness structure, the thickness of the first active material part 21 is less than the thickness of the second active material part 22, so that the first active material part 21 and the second active material part 22 form a stepped structure; in other examples, the thickness of the first active material part 21 can also be steppedly reduced, so that the first active material part 21 is a stepped structure; or, along the direction of the conductive part 121 towards the extension part 122, the thickness of the first active material part 21 can also slowly decrease, so that the thickness of the first active material part 21 slowly decreases, and the shape of the first active material part 21 is more smooth or smooth.

[0216] In the forming process of the first pole piece 1, the active material layer 20 can be rolled to compress the active material layer 20; and the arrangement of the first active material part 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.

[0217] In some embodiments, the spacing between the first welding mark 51 and the active material layer 20 is in the range of 0.5mm-2.8mm.

[0218] It can be understood that 0.5mm≤S1≤2.8mm.

[0219] By adopting the technical solution of this embodiment, the distance between the active material layer 20 and the first solder print 51 is more reasonable, and the design of 0.5mm≤S1≤2.8mm can better balance the connection reliability of the conductive member 30 and the energy density of the battery monomer 100.

[0220] In some embodiments, the conductive member 30 includes a first connecting portion 31 and at least one second connecting portion 32, the first connecting portion 31 and the second connecting portion 32 are arranged along the first direction, the first connecting portion 31 and the second connecting portion 32 are connected, the second connecting portion 32 is connected with the electrode lead-out portion 2011, the first connecting portion 31 is soldered to the surface of the extension portion 122 away from the insulating base body 11 and forms the first solder print 51, and the second connecting portion 32 is located at the side of the extension portion 122 away from the conductive portion 121.

[0221] The first connecting portion 31 can be a part of the conductive member 30 soldered with the metal layer 12, and the second connecting portion 32 can be a part of the conductive member 30 connected with the electrode lead-out portion 2011.

[0222] In some examples, the first connecting portion 31 can be covered on the extension portion 122 and soldered with the extension portion 122, and the second connecting portion 32 can be led out from the first connecting portion 31 away from the active material layer 20 along the first direction to protrude out of the insulating base body 11, i.e. along the thickness direction of the current collector 10, the projection of the first connecting portion 31 is located within the projection of the extension portion 122, and the projection of the second connecting portion 32 is located outside the projection range of the extension portion 122; in this way, the connection positions of the extension portion 122 and the electrode lead-out portion 2011 on the conductive member 30 are different, the connection is convenient, and the mutual influence between the two connections can be reduced, which is beneficial to 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 coincide along the thickness direction of the current collector 10.

[0223] In some cases, when the pole piece is wound to form the electrode assembly 101, the insulating base 11 insulates the adjacent two layers of the metal layer 12, which makes it difficult to directly connect between the adjacent two layers of the metal layer 12 to transmit current outward through the insulating base 11, so that the current can only be transmitted outward by the outermost layer of the metal layer 12, resulting in poor conductivity, low fast charging performance, and easy local overheating, affecting the use reliability of the battery monomer 100. The battery monomer 100 of the embodiment of the application utilizes the welding of the first connecting part 31 of the conductive member 30 and the extension part 122, and the second connecting part 32 of the conductive member 30 protrudes out of the insulating base 11, so that the second connecting part 32 can electrically conduct the adjacent two layers of the metal layer 12, thereby breaking the insulation limitation of the insulating base 11, effectively improving the conductivity of the first pole piece 1, improving the fast charging performance of the battery monomer 100, reducing the heat generation of the battery monomer 100, and improving the use reliability of the battery monomer 100.

[0224] When the pole pieces are stacked to form the electrode assembly 101, the insulating base 11 insulates the adjacent two metal layers 12, which makes it difficult to directly connect between the adjacent two metal layers 12 to transmit 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 easy local overheating, affecting the use reliability of the battery monomer 100. The battery monomer 100 of the embodiment of the application utilizes the welding of the first connecting part 31 of the conductive member 30 and the extension part 122, and the second connecting part 32 of the conductive member 30 protrudes out of the insulating base 11, so that the second connecting part 32 can electrically conduct the adjacent two metal layers 12, thereby breaking the insulation limitation of the insulating base 11, effectively improving the conductivity of the first pole piece 1, improving the fast charging performance of the battery monomer 100, reducing the heat generation of the battery monomer 100, and improving the use reliability of the battery monomer 100.

[0225] The first connecting part 31 is stacked on the surface of the extension part 122 away from the insulating base 11 and is welded to the surface of the extension part 122 away from the insulating base 11. The trace formed by welding is the first welding mark 51.

[0226] In the first direction, the first welding mark 51 is spaced apart from the active material layer 20, so that the first connecting part 31 will not be welded to the active material layer 20, which is beneficial to reduce the risk of false welding and other problems, and is beneficial to improve the connection reliability and overcurrent capacity of the metal layer 12 and the conductive member 30.

[0227] In some examples, the second connecting part 32 and the electrode lead-out part 2011 can be connected by direct welding, and can also be welded by a conductive piece (such as a jumper sheet, etc.). The welding method is convenient for connection operation and convenient for processing and manufacturing. Of course, other connection methods can also be used.

[0228] By adopting the technical solutions of this embodiment, the second connecting portion 32 protrudes beyond the extension portion 122, so that the second connecting portion 32 can be conveniently connected with the electrode lead-out portion 2011, and the manufacturing process is more convenient.

[0229] In some embodiments, along the first direction, the first welding mark 51 and the end surface of the first connecting portion 31 facing the active material layer 20 are spaced apart.

[0230] In some examples, the first tab 1 is a positive tab, and a gap exists between the first welding mark 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 welding mark 51 and the end surface of the first connecting portion 31 facing the active material layer 20, so that the first welding mark 51 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, thereby 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.

[0231] In some examples, the first tab 1 is a negative tab, and a gap exists between the first welding mark 51 and the active material layer 20. The gap can provide a spacing space for the end surface of the first welding mark 51 and the end surface of the first connecting portion 31 facing the active material layer 20, so that the second welding mark portion 512 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, thereby 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 be in contact with the active material layer 20 or not.

[0232] A gap exists between the first welding mark 51 and the end surface of the first connecting portion 31 facing the active material layer 20, so that the first welding mark 51 does not extend to the end surface of the first connecting portion 31 facing the active material layer 20, thereby 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.

[0233] In some embodiments, along the first direction, the distance between the first welding mark 51 and the end surface of the first connecting portion 31 facing the active material layer 20 is in the range of 0.3mm to 1.2mm.

[0234] Along the first direction, the distance between the first welding mark 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.

[0235] The design with S2≥1.2mm ensures a gap between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20, preventing the first solder mark 51 from extending to the end face of the first connection portion 31 facing the active material layer 20 and reducing the risk of the end face of the first connection portion 31 facing the active material layer 20 being soldered through or cracked. The design with S2≤1.2mm ensures that the gap between the first solder mark 51 and the end face of the first connection portion 31 facing the active material layer 20 is not too large, which is beneficial to increasing the coverage area of ​​the active material layer 20 on the metal layer 12 and improving the energy density of the battery cell 100.

[0236] The value of S2 can be 0.3mm, 1.2mm, or any value between 0.3mm and 1.2mm. For example, the value of S2 can be, but is not limited to, 0.3mm, 0.6mm, 0.8mm, 1mm, or 1.2mm.

[0237] By adopting the technical solution of this embodiment, the reliability and energy density of the battery cell 100 can be well balanced.

[0238] In some embodiments, the first solder mark 51 includes a first solder mark portion 511, the extension portion 122 includes at least one protrusion 1222, the protrusion 1222 is connected to the conductive portion 121, and the first connecting portion 31 is soldered to the surface of the protrusion 1222 facing away from the insulating substrate 11 to form the first solder mark portion 511; along the second direction, the size l1 of the protrusion 1222 is smaller than the size L1 of the conductive portion 121, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0239] The protrusion 1222 can refer to a protruding structure on the edge of the metal layer 12, and along the second direction, the size l1 of the protrusion 1222 is smaller than the size L1 of the conductive portion 121. The number of protrusions 1222 can be one or more.

[0240] In some examples, the protrusion 1222 extends directly outward from the end of the conductive portion 121 along the first direction. Alternatively, the extension 122 may also include a portion connecting the conductive portion 121 and the protrusion 1222.

[0241] The first connecting part 31 is stacked with the protrusion 1222 facing away from the surface of the insulating substrate 11 and welded to the protrusion 1222. The trace formed by the welding is the first solder mark 511.

[0242] In some examples, the first connecting portion 31 may be welded to the entire protrusion 1222, or the first connecting portion 31 may be welded to a portion of the protrusion 1222, while another portion of the first protrusion 1222 may not be welded to the first connecting portion 31.

[0243] By adopting the technical scheme of the embodiment, the first connecting part 31 and the protruding part 1222 are connected by welding, the connection mode is simple, and the first tab 1 is convenient to manufacture; in addition, the first connecting part 31 and the protruding part 1222 can directly pass current by using the first welding part 511, which is beneficial to improve the current passing capacity between the first connecting part 31 and the protruding part 1222; in addition, along the second direction, the size l1 of the protruding part 1222 is smaller than the size L1 of the conductive part 121, the protruding part 1222 is easy to be connected with the electrode lead-out part 2011 by being bent along with the conductive member 30, the processing and manufacturing are convenient, and the space occupied after the conductive member 30 is bent is reduced, which is beneficial to improve the energy density of the battery monomer 100.

[0244] In some embodiments, along the second direction, the first welding part 511 extends from one side of the protruding part 1222 to the other side of the protruding part 1222.

[0245] Along the first direction, the projection of the first welding part 511 falls within the projection of the protruding part 1222.

[0246] In the manufacturing process of the first tab 1, the conductive member 30 can be welded with the edge part of the equal-length current collector 10 by ultrasonic welding (for example, double-roller continuous ultrasonic welding) or other welding methods, and a equal-width welding mark is formed, and then the conductive member 30 is cut by laser die cutting or other cutting methods to form a tab, so as to be connected with the electrode lead-out part 2011; and in the cutting process, first, cutting is performed along the second direction between the equal-width welding mark and the active material layer 20, then cutting is performed along the direction towards the equal-width welding mark until the equal-width welding mark is left, then cutting is continuously performed away from the active material layer 20 for a distance, then cutting is performed along the second direction for a distance, then cutting is performed along the direction towards the equal-width welding mark until the equal-width welding mark is left, and then cutting is performed along the second direction, so that a first welding part 511 is obtained, and the plurality of first welding parts 511 are obtained by repeating the above process.

[0247] By adopting the technical scheme of the embodiment, along the second direction, the first welding part 511 can occupy the entire protruding part 1222, the size L4 of the first welding part 511 along the second direction is large, which is beneficial to improve the current passing area between the first connecting part 31 and the protruding part 1222, improve the current passing capacity between the first connecting part 31 and the protruding part 1222, reduce the risk of heating, and improve the fast-charging performance and use reliability of the battery monomer 100.

[0248] In some embodiments, the protruding portion 1222 comprises a first protruding sub-portion 12221 and a second protruding sub-portion 12222, the second protruding sub-portion 12222 is connected between the conductive portion 121 and the first protruding sub-portion 12221; along the second direction, the size l3 of the second protruding sub-portion 12222 is smaller than the size l2 of the first protruding sub-portion 12221, and the size l2 of the first protruding sub-portion 12221 is smaller than the size L1 of the conductive portion 121; the first solder portion 511 comprises a first solder sub-portion 5111; the first connecting portion 31 is soldered to the surface of the first protruding sub-portion 12221 away from the insulating base 11 and forms the first solder sub-portion 5111.

[0249] For example, the protruding portion 1222 has a stepped structure, along the first direction, the protruding portion 1222 is divided into two parts, the part close to the conductive portion 121 is the first protruding sub-portion 12221, and the part away from the conductive portion 121 is the second protruding sub-portion 12222; l2>l3, which is equivalent to increasing the size of the first protruding sub-portion 12221 along the second direction, improving the flow area between the protruding portion 1222 and the conductive portion 121, improving the flow capacity, and reducing the heat generation of the battery monomer 100.

[0250] The first connecting portion 31 is soldered to the surface of the first protruding sub-portion 12221 away from the insulating base 11, and the trace generated by soldering is the first solder sub-portion 5111.

[0251] For example, the first connecting portion 31 can be soldered to the side of the first protruding sub-portion 12221 towards the conductive portion 121, so that the first solder sub-portion 5111 is directly connected with the conductive portion 121; in this way, the first connecting portion 31 and the conductive portion 121 can directly flow through the first solder portion 511, which is conducive to improving the flow capacity between the first connecting portion 31 and the conductive portion 121, reducing the heat generation of the battery monomer 100, and improving the fast charging performance and use reliability of the battery monomer 100; of course, the first connecting portion 31 can also be soldered to the side of the first protruding sub-portion 12221 away from the conductive portion 121, so that the first solder sub-portion 5111 is spaced apart from the conductive portion 121.

[0252] By adopting the technical scheme of this embodiment, the first connecting portion 31 is soldered to the first protruding sub-portion 12221 and forms the first solder sub-portion 5111, the size of the first protruding sub-portion 12221 along the second direction is large, which is conducive to improving the soldering area of the protruding portion 1222 and the first connecting portion 31, improving the flow area between the protruding portion 1222 and the first connecting portion 31, improving the flow capacity, reducing the heat generation of the battery monomer 100, and improving the fast charging performance and use reliability of the battery monomer 100; in addition, along the second direction, the size l3 of the second protruding sub-portion 12222 is small, which is conducive to reducing the occupied space of the protruding portion 1222 and improving the energy density of the battery monomer 100.

[0253] In some embodiments, along the second direction, the first welding sub-part 5111 extends from one side edge of the first protruding sub-part 12221 to another side edge of the first protruding sub-part 12221.

[0254] Along the first direction, the projection of the first welding sub-part 5111 falls within the projection of the first protruding sub-part 12221.

[0255] By adopting the technical solutions of this embodiment, along the second direction, the size of the first welding sub-part 5111 is large, which is conducive to improving the welding area between the protruding part 1222 and the first connecting part 31, improving the flow area between the protruding part 1222 and the first connecting part 31, and improving the flow capacity, thereby reducing the heat generation of the battery monomer 100 and being conducive to improving the fast-charging performance and use reliability of the battery monomer 100.

[0256] In some embodiments, the first welding part 511 further comprises a second welding sub-part 5112, and the first connecting part 31 is welded to the surface of the second protruding sub-part 12222 away from the insulating base body 11 and forms the second welding sub-part 5112.

[0257] For example, the surface of the second protruding sub-part 12222 away from the insulating base body 11 is welded to the first connecting part 31, and the trace generated by the welding is the second welding sub-part 5112.

[0258] By adopting the technical solutions of this embodiment, the second protruding sub-part 12222 is also welded to the first connecting part 31, which is conducive to improving the flow area between the first connecting part 31 and the protruding part 1222 and improving the flow capacity between the first connecting part 31 and the protruding part 1222.

[0259] In some embodiments, along the second direction, the second welding sub-part 5112 extends from one side edge of the second protruding sub-part 12222 to another side edge of the second protruding sub-part 12222.

[0260] Along the first direction, the projection of the second welding sub-part 5112 falls within the projection of the second protruding sub-part 12222.

[0261] By adopting the technical solutions of this embodiment, the size of the second welding sub-part 5112 along the second direction is large, which is conducive to improving the welding area between the first connecting part 31 and the protruding part 1222, improving the flow area between the first connecting part 31 and the protruding part 1222, and improving the flow capacity between the first connecting part 31 and the protruding part 1222.

[0262] Please refer to Figs. 11-17, in some embodiments, the first welding mark 51 includes a second welding mark portion 512, the extension portion 122 further includes a transition portion 1221, the transition portion 1221 is connected between the protruding portion 1222 and the conductive portion 121, the first connecting portion 31 is welded to the surface of the transition portion 1221 away from the insulating substrate 11 and forms the second welding mark portion 512; along the second direction, the size L2 of the transition portion 1221 is greater than the sum of the sizes l1 of all the protruding portions 1222, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0263] For example, along the first direction, the extension portion 122 is divided into two parts, wherein the part close to the conductive portion 121 is the transition portion 1221, the part away from the conductive portion 121 is the conductive portion 121, and the protruding portion 1222 protrudes away from the conductive portion 121 from the edge of the transition portion 1221 away from the conductive portion 121; the conductive portion 121 is covered with the active material layer 20, and the transition portion 1221 and the protruding portion 1222 are not covered with the active material layer 20, so as to facilitate the connection with the first connecting portion 31.

[0264] In some examples, the protruding portion 1222 extends outwardly along the first direction from the side of the transition portion 1221 away from the conductive portion 121, and along the second direction, the size of the protruding portion 1222 can be equal to the size of the transition portion 1221, or along the second direction, the sum of the sizes l2 of the first protruding sub-portions 12221 of all the protruding portions 1222 is less than or equal to the size L2 of the transition portion 1221.

[0265] The first connecting portion 31 is welded to the surface of the transition portion 1221 away from the insulating substrate 11, and the trace generated by the welding of the transition portion 1221 and the first connecting portion 31 is the second welding mark portion 512.

[0266] In some examples, the first welding mark 51 includes the second welding mark portion 512 and the first welding mark portion 511, the first welding mark portion 511 is located between the second welding mark portion 512 and the active material layer 20, that is, the first connecting portion 31 is welded to the transition portion 1221 and the protruding portion 1222 at the same time.

[0267] In some examples, the first welding mark 51 includes the second welding mark portion 512, and the first connecting portion 31 is welded only to the transition portion 1221, but not to the protruding portion 1222.

[0268] In some examples, the first welding mark 51 can only include the first welding mark portion 511, that is, the first connecting portion 31 is welded to the protruding portion 1222, but not to the transition portion 1221.

[0269] Along the second direction, the size L2 of the transition portion 1221 is greater than the sum of the sizes l1 of all the protruding portions 1222, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0270] By adopting the technical scheme of this embodiment, the surface of the transition portion 1221 facing away from the surface of the insulating base body 11 is welded with the first connecting portion 31, so that part of the current can directly flow into or out of the first connecting portion 31 through the transition portion 1221, the overcurrent pressure between the protruding portion 1222 and the transition portion 1221 is reduced, and the heat generation at the connection between the protruding portion 1222 and the transition portion 1221 is reduced; in addition, the first connecting portion 31 and the transition portion 1221 are connected in a welding manner, the connection manner is simple, and the manufacturing of the first pole piece 1 is facilitated; the second welding mark portion 512 can be directly used for overcurrent between the first connecting portion 31 and the transition portion 1221, the overcurrent capacity between the first connecting portion 31 and the transition portion 1221 is improved, and the heat generation of the battery monomer 100 is reduced.

[0271] In some embodiments, along the second direction, the size of the conductive portion 121 is L1, and the size of the transition portion 1221 is L2, and 0.8≤L2 / L1≤1.

[0272] 0.8≤L2 / L1≤1, along the second direction, the size L2 of the transition portion 1221 is less than or equal to the size L1 of the conductive portion 121, and the size L2 of the transition portion 1221 is greater than or equal to 0.8 times the size L1 of the conductive portion 121, the size L2 of the transition portion 1221 exceeds more than half of the size L1 of the conductive portion 121, the larger the size L2 of the transition portion 1221, the larger the connection area of the transition portion 1221 and the first connecting portion 31 can be set, and the better the overcurrent capacity between the transition portion 1221 and the first connecting portion 31.

[0273] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1221 can be located at the middle position of the conductive portion 121, and the two ends of the transition portion 1221 are not flush with the conductive portion 121.

[0274] In some examples, 0.8≤L2 / L1<1, along the second direction, the transition portion 1221 can be arranged to be deviated from one end of the conductive portion 121, so that one end of the transition portion 1221 is flush with the conductive portion 121, and the other end is not flush, or both ends are not flush. The value of L2 / L1 can be but is not limited to 0.8, 1, or any value between 0.8 and 1. For example, the value of L2 / L1 can be but is not limited to 0.8, 0.85, 0.9, 0.95, 1.

[0275] By adopting the technical scheme of this embodiment, the design of 0.8≤L2 / L1≤1 makes the size of the transition portion 1221 along the second direction large, which is beneficial to increase the connection area between the first connecting portion 31 and the transition portion 1221, improve the flow capacity at the connection between the first connecting portion 31 and the transition portion 1221, improve the flow capacity of the first pole piece 1, reduce the heat generation of the battery monomer 100, and improve the fast-charging performance of the battery monomer 100.

[0276] In some embodiments, L2=L1.

[0277] L2 / L1=1, along the second direction, the size L2 of the transition portion 1221 is equal to the size L1 of the conductive portion 121, the two ends of the transition portion 1221 are flush with the conductive portion 121 along the second direction, and the transition portion 1221 and the conductive portion 121 are of equal length.

[0278] By adopting the technical scheme of this embodiment, the design of L2=L1 makes the size of the transition portion 1221 along the second direction large, which is beneficial to design the connection area between the first connecting portion 31 and the transition portion 1221 to be large, the flow capacity at the connection between the first connecting portion 31 and the transition portion 1221 is best, and the flow capacity of the first pole piece 1 can be effectively improved, the heat generation of the battery monomer 100 is reduced, and the fast-charging performance of the battery monomer 100 is improved.

[0279] In some embodiments, the first welding mark 51 can only be the first welding mark portion 511, that is, the first connecting portion 31 is welded with the protruding portion 1222, and is not welded with the transition portion 1221.

[0280] In some embodiments, along the second direction, the size L2 of the transition portion 1221 is L2, the size L3 of the second welding mark portion 512 is L3, and 0.8≤L3 / L2≤1.

[0281] 0.8≤L3 / L2≤1, along the second direction, the size L3 of the second welding mark portion 512 can be less than or equal to the size L2 of the transition portion 1221, the size L3 of the second welding mark portion 512 is greater than or equal to 0.8 times the size L2 of the transition portion 1221, the size L3 of the second welding mark portion 512 is more than half of the size L2 of the transition portion 1221, and the longer the size L3 of the second welding mark portion 512, the larger the welding area of the transition portion 1221 and the first connecting portion 31, and the better the flow capacity at the connection between the transition portion 1221 and the first connecting portion 31.

[0282] In some examples, 0.8≤L3 / L2<1, along the second direction, the second welding mark portion 512 can be located at the middle position of the transition portion 1221, and the two ends of the second welding mark portion 512 are not flush with the transition portion 1221.

[0283] In some examples, 0.8≤L2 / L1<1, the second welding part 512 is arranged at one end of the transition part 1221 which can also be biased, so that one end of the transition part 1221 is flush with the transition part 1221, the other end is not flush, or both ends are not flush.

[0284] 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, or 1.

[0285] By adopting the technical solutions of this embodiment, the design of 0.8≤L3 / L2≤1 makes the size of the transition part 1221 along the second direction larger, which is conducive to increasing the connection area between the first connecting part 31 and the transition part 1221, improving the flow capacity at the connection between the first connecting part 31 and the transition part 1221, improving the flow capacity of the first tab 1, reducing the heat generation of the battery monomer 100, and improving the fast-charging performance of the battery monomer 100.

[0286] In some embodiments, L3=L2.

[0287] L3 / L2=1, along the second direction, the size L3 of the second welding part 512 is equal to the size L2 of the transition part 1221, and both ends of the second welding part 512 are flush with the transition part 1221.

[0288] In some examples, the convex part 1222 is welded with the first connecting part 31 at the same time as the transition part 1221, thereby forming an entire welding, and the first connecting part 31 is welded to the transition part 1221, which can effectively increase the welding area of the first connecting part 31 and the metal layer 12, and improve the flow area between the first connecting part 31 and the metal layer 12, which is conducive to improving the flow capacity between the first connecting part 31 and the metal layer 12.

[0289] In the process of cutting the conductive member 30, first, cutting is performed in the second direction on the equal-width weld, then cutting is performed in the direction away from the active material layer 20 until after leaving the equal-width weld, cutting is continued in the direction away from the active material layer 20 for a distance, then cutting is continued in the second direction for a distance, then cutting is performed in the direction toward the active material layer 20 until after cutting the equal-width weld for a distance, then cutting is continued in the second direction on the equal-width weld, and so on, so that the first weld 51 is obtained; wherein, taking the cutting position of cutting in the second direction on the equal-width weld as a reference, in the first direction, the part of the first weld 51 located on the side of the cutting position toward the active material layer 20 is the second weld part 512, and the part located on the side of the cutting position away from the active material layer 20 is the first weld part 511, and the first weld part 511 can be a protruding structure away from the active material layer 20 of the second weld part 512; 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 part 1222, and during the cutting process in the second direction, the part located between the protruding part 1222 and the active material layer 20 forms the transition part 1221.

[0290] By adopting the technical scheme of this embodiment, the design of L3 / L2=1 makes the size of the second weld part 512 in the second direction larger, which is beneficial to designing the welding area between the first connecting part 31 and the transition part 1221 to be larger, the overcurrent capacity at the connection between the first connecting part 31 and the transition part 1221 is best, which can effectively improve the overcurrent capacity of the first tab 1, reduce the heat generation of the battery monomer 100, and improve the fast-charging performance of the battery monomer 100.

[0291] In some embodiments, in the second direction, the size L4 of the first weld part 511 is smaller than the size L3 of the second weld part 512.

[0292] By adopting the technical scheme of this embodiment, in the second direction, the size L3 of the second weld part 512 is large, the welding area of the transition part 1221 and the first connecting part 31 is large, which is beneficial to improve the overcurrent capacity of the first connecting part 31 and the transition part 1221, and is beneficial to improve the fast-charging performance and use reliability of the battery monomer 100.

[0293] In some embodiments, the number of protruding parts 1222 is multiple, and the multiple protruding parts 1222 are arranged at intervals in the second direction, each protruding part 1222 is welded with the first connecting part 31, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0294] The number of protruding parts 1222 is multiple, for example: two, three, four, etc.; the multiple protruding parts 1222 are arranged at intervals in the second direction.

[0295] After the first pole piece 1 is wound or stacked, the plurality of protruding portions 1222 are stacked together, and the plurality of second connecting portions 32 are also stacked together, thereby breaking the insulation limit of the insulation base 11, effectively improving the electrical conductivity of the first pole piece 1, improving the fast-charging performance of the battery monomer 100, reducing the heat generation of the battery monomer 100, and improving the use reliability of the battery monomer 100.

[0296] The plurality of protruding portions 1222 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 1222 is less than the size L2 of the transition portion 1221, and along the second direction, the sum of the sizes L4 of all the first solder portions 511 is less than the size L3 of the second solder portion 512. The size L3 of the second solder portion 512 is large, which is conducive to improving the welding area of the transition portion 1221 and the first connecting portion 31, improving the flow capacity at the connection between the transition portion 1221 and the conductive member 30, improving the flow capacity of the first pole piece 1, reducing the heat generation of the battery monomer 100, and improving the fast-charging performance and use reliability of the battery monomer 100.

[0297] Among the plurality of first solder portions 511, along the second direction, some of the first solder portions 511 can have the same size L4, all of the first solder portions 511 can have completely different sizes L4, or all of the first solder portions 511 can have the same size L4.

[0298] By adopting the technical scheme of the embodiment, the plurality of protruding portions 1222 are arranged at intervals along the second direction, which is conducive to dividing the conductive portion 121 into a plurality of regions along the second direction, and one region can correspond to one protruding portion 1222. The electrons in each region can be transmitted to the electrode lead-out portion 2011 through the corresponding protruding portion 1222, so that the electrons in the conductive portion 121 are transmitted in a region-by-region manner, the transmission path of the electrons in each region is short to the corresponding protruding portion 1222, which is conducive to reducing the transmission distance of the electrons, reducing the overall resistance of the first pole piece 1, and improving the fast-charging performance and use reliability of the battery monomer 100.

[0299] In some embodiments, the first connecting portion 31 includes a plurality of first connecting sub-portions 311, the plurality of first connecting sub-portions 311 are arranged at intervals along the second direction, the number of the second connecting portions 32 is a plurality, and each first connecting sub-portion 311 is connected to each second connecting portion 32 one by one; each first connecting sub-portion 311 is welded to the surface of each protruding portion 1222 away from the insulation base 11 one by one.

[0300] The first connecting sub portion 311 can refer to the portion of the first connecting portion 31 covering the protruding portion 1222. The number of the first connecting sub portions 311, the number of the second connecting portions 32, and the number of the protruding portions 1222 are the same, one first connecting sub portion 311 corresponds to one protruding portion 1222, one first connecting sub portion 311 corresponds to one second connecting portion 32, and one first connecting sub portion 311 and one protruding portion 1222 are welded to form one first welding portion 511.

[0301] By adopting the technical scheme of the embodiment, the plurality of first connecting sub portions 311 of the first connecting portion 31 are arranged at intervals along the second direction, and there is a gap between the two adjacent first connecting sub portions 311, which can reduce the required material of the first connecting portion 31 and reduce the manufacturing cost of the battery monomer 100.

[0302] In some embodiments, the number of the protruding portions 1222 is a plurality, and the plurality of protruding portions 1222 are arranged at intervals along the second direction, the second direction being perpendicular to the first direction and the thickness direction of the current collector 10; the first connecting portion 31 includes a second connecting sub portion 312 and 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 each first connecting sub portion 311 is welded to the surface of each protruding portion 1222 away from the insulating base body 11; the number of the second connecting portions 32 is a plurality, each first connecting sub portion 311 is connected to each second connecting portion 32 on one side along the first direction, and the other side of each first connecting sub portion 311 is connected to the second connecting sub portion 312, 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 1221 away from the insulating base body 11.

[0303] The second connecting sub portion 312 can refer to the portion of the first connecting portion 31 covering the transition portion 1221; the second connecting sub portion 312 is arranged continuously along the second direction, for example, along the second direction, the second connecting sub portion 312 extends from one side of the transition portion 1221 to the other side of the transition portion 1221.

[0304] The second connecting sub portion 312 is welded to the surface of the transition portion 1221 away from the insulating base body 11 to form a second welding portion 512.

[0305] By adopting the technical solutions of the embodiment, the second connecting sub-parts 312 are arranged continuously along the second direction, the plurality of first connecting sub-parts 311 can be connected as a whole, the second connecting sub-parts 312 can play a good supporting role on the first connecting sub-parts 311, the risk of the first connecting sub-parts 311 being bent to be inserted between the first pole piece 1 and the second pole piece 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-parts 312 is large, which is beneficial to improve the welding area between the second connecting sub-parts 312 and the transition part 1221, is beneficial to improve the overcurrent capacity of the connection between the first connecting part 31 and the transition part 1221, improves the overcurrent capacity of the first pole piece 1, and improves the fast charging performance and use reliability of the battery monomer 100.

[0306] In some embodiments, along the second direction, the sum of the sizes L4 of all the first welding parts 511 is less than the size L3 of the second welding part 512.

[0307] By adopting the technical solutions of the embodiment, along the second direction, the sum of the sizes L4 of all the first welding parts 511 is less than the size L3 of the second welding part 512, and the size L3 of the second welding part 512 is large, which is beneficial to improve the welding area between the transition part 1221 and the first connecting part 31, is beneficial to improve the overcurrent capacity of the connection between the transition part 1221 and the conductive member 30, is beneficial to improve the overcurrent capacity of the first pole piece 1, reduces the heat generation of the battery monomer 100, and improves the fast charging performance and use reliability of the battery monomer 100.

[0308] In some examples, the second welding part 512 and the first welding part 511 are directly connected.

[0309] The second welding part 512 and the first welding part 511 form a whole first welding 51, and there is no obvious boundary between them; the whole first welding 51 can cover the junction between the protruding part 1222 and the transition part 1221; in the actual manufacturing process, the second welding part 512 and the first welding part 511 are formed by cutting the above-mentioned welding with the same width.

[0310] In some examples, the second welding part 512 and the first welding part 511 adopt the structure form of welding spots, the welding spot spacing in the second welding part 512 is the same as the welding spot spacing of the first welding part 511; for example, the welding spots in the second welding part 512 and the first welding part 511 are not welded to the junction line of the protruding part 1222 and the transition part 1221, and the spacing between the two adjacent welding spots in the second welding part 512 and the first welding part 511 is equal to the welding spot spacing in the second welding part 512; for example, the welding spots are welded to the junction line of the protruding part 1222 and the transition part 1221, so that the second welding part 512 and the first welding part 511 are connected as a whole welding.

[0311] By adopting the technical scheme of the embodiment, the first welding mark 51 can cover the junction of the protruding portion 1222 and the transition portion 1221, a part of the current can directly flow to the first connecting portion 31 through the transition portion 1221, the overcurrent pressure at the junction of the protruding portion 1222 and the transition portion 1221 is reduced, the overcurrent capacity of the first tab 1 is improved, the heat generation of the battery monomer 100 is reduced, and the fast-charging performance of the battery monomer 100 is improved.

[0312] In some embodiments, the first connecting portion 31 and the active material layer 20 are spaced apart along the first direction.

[0313] The first connecting portion 31 is not in direct contact with the active material layer 20, but there is a certain gap, so that the first connecting portion 31 is not in contact with the active material layer 20.

[0314] In some examples, the first tab 1 is a positive tab, and the first connecting portion 31 is not in contact with the active material layer 20, which can reduce the risk of lithium precipitation and the like, and improve the use reliability of the battery monomer 100. In other examples, the first tab 1 is a negative tab, and the first connecting portion 31 can be in contact with the active material layer 20 or not.

[0315] By adopting the technical scheme of the embodiment, the first connecting portion 31 is not in contact with the active material layer, which can reduce the mutual influence between the two and improve the use reliability of the battery monomer 100.

[0316] In some embodiments, the electrode assembly 101 further comprises an insulating member 40, and the insulating member 40 comprises a first insulating portion 41 covering the surface of the extension portion 122 away from the insulating base body 11, and the entire first insulating portion 41 is located between the first welding mark 51 and the active material layer 20.

[0317] The insulating member 40 can refer to a component capable of insulation, and the insulating member 40 comprises the first insulating portion 41, which can refer to an insulating component covering the surface of the extension portion 122 away from the active material layer 20; the first insulating portion 41 can be but is not limited to an insulating coating, an insulating glue (for example, hot melt glue), or an insulating adhesive tape.

[0318] Along the thickness direction of the current collector 10, the first insulating portion 41 is not coincident with the first welding mark 51, and the first insulating portion 41 is spaced apart from the first welding mark 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 extension portion 122; or, the first insulating portion 41 is only coincident with the first welding mark 51 at the edge, and the edge of the first welding mark 51 is coincident with the edge of the first insulating portion 41, which can also reduce the risk of false welding between the first connecting portion 31 and the metal layer 12.

[0319] By adopting the technical scheme of this embodiment, the risk of virtual welding between the first connecting portion 31 and the extension portion 122 can be reduced, the risk of virtual welding between the first connecting portion 31 and the extension portion 122 can be reduced, the connection reliability of the first connecting portion 31 and the extension portion 122 can be improved, and the overcurrent capacity can also be improved.

[0320] In some embodiments, the first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0321] In some examples, the entire first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0322] In some examples, in the case that the first connecting portion 31 is welded only with the protruding portion 1222 and the first connecting portion 31 is spaced apart from the transition portion 1221, a part of the first insulating portion 41 covers the first protruding sub-portion 12221 and another part covers the transition portion 1221. In this way, the metal layer 12 located between the first connecting portion 31 and the active material layer 20 can be fully covered, and at the same time, the root of the protruding portion 1222 can be supported, which can reduce the damage such as cracks and fractures of the root of the protruding portion 1222 during the manufacturing process of the battery device 1100, and can improve the electron transport capacity of the root of the protruding portion 1222, and improve the fast charging performance and use reliability of the battery monomer 100. Of course, in other examples, the first insulating portion 41 can cover only the transition portion 1221.

[0323] In some examples, in the case that the protruding portion 1222 and the transition portion 1221 are both welded with the first connecting portion 31, the first insulating portion 41 covers the transition portion 1221.

[0324] By adopting the technical scheme of this embodiment, the first insulating portion 41 can support the part of the extension portion 122 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 can improve the electron transport capacity of this part, and improve the fast charging performance and use reliability of the battery monomer 100. In addition, the first insulating portion 41 can also insulate this part, reduce the risk of short circuit of the battery monomer 100, and improve the use reliability of the battery monomer 100.

[0325] In some embodiments, the insulating member 40 further comprises a second insulating portion 42, at least a part of the second insulating portion 42 covers the first welding mark 51.

[0326] The second insulating portion 42 covers at least part of the first solder print 51 on the surface of the first connecting portion 31 facing away from the extension portion 122. The second insulating portion 42 can cover part of the first solder print 51 or the entire first solder print 51. The second insulating portion 42 can be, but is not limited to, an insulating coating, an insulating adhesive (e.g., hot melt adhesive), or an insulating adhesive tape. The first insulating portion 41 and the second insulating portion 42 can be integrally formed or can be two separate components.

[0327] Part of the second insulating portion 42 can cover the first solder print 51, and the other part can cover the first insulating portion 41 or the active material layer 20. Alternatively, the entire second insulating portion 42 can cover the first solder print 51.

[0328] In some examples, the first solder print 51 includes a first solder print portion 511, and the second insulating portion 42 covers at least part of the first solder print portion 511. The second insulating portion 42 can cover part of the first solder print portion 511 or the entire first solder print portion 511.

[0329] In some examples, the first solder print 51 includes a second solder print portion 512 and a first solder print portion 511, and the second insulating portion 42 covers the second solder print portion 512 and the first solder print portion 511.

[0330] The first connecting portion 31 is welded to the extension portion 122, which can easily generate a pointed protrusion, metal debris, or other components on the surface of the first solder print 51. The second insulating portion 42 of the present application covers the surface of the first solder print 51, which can prevent the pointed protrusion, metal debris, or other components on the surface of the first solder print 51 from piercing the separator 3 and connecting with the second tab 2, thereby reducing the risk of short circuit of the battery monomer 100 and improving the use reliability of the battery monomer 100.

[0331] In some embodiments, the second insulating portion 42 protrudes from the end surface of the first protruding sub-portion 12221 facing away from the conductive portion 121 in the direction pointing to the extension portion 122.

[0332] In the thickness direction of the current collector 10, the projection of the end surface of the first protruding sub-portion 12221 facing away from the conductive portion 121 falls within the projection of the second insulating portion 42.

[0333] In some examples, during the manufacturing process of the pole piece, the end surface of the first protruding sub-part 12221 facing away from the conductive part 121 is cut, resulting in burrs on the end surface of the first protruding sub-part 12221 facing away from the conductive part 121. The second insulating part 42 can block the burrs on the end surface of the first protruding sub-part 12221 facing away from the conductive part 121, reduce the risk of short circuit inside the battery monomer 100, and help improve the use reliability of the battery monomer 100. In addition, the second insulating part 42 can completely cover the first solder print sub-part 5111, reducing the risk of short circuit caused by sharp protrusions, metal debris and other components on the first solder print sub-part 5111, and helping to improve the use reliability of the battery monomer 100.

[0334] In some embodiments, along the direction of the conductive part 121 pointing to the extension part 122, the second insulating part 42 protrudes from the edge of the second solder print sub-part 5112 facing away from the first protruding sub-part 12221.

[0335] Along the thickness direction of the current collector 10, the projection of the edge of the second solder print sub-part 5112 facing away from the first protruding sub-part 12221 falls within the projection of the second insulating part 42, so that the second insulating part 42 can completely cover the second solder print sub-part 5112 and the first solder print sub-part 5111.

[0336] During the manufacturing process of the pole piece, the second insulating part 42 can completely cover the second solder print sub-part 5112 and the first solder print sub-part 5111, reducing the risk of short circuit caused by sharp protrusions, metal debris and other components on the second solder print sub-part 5112 and the first solder print sub-part 5111, and helping to improve the use reliability of the battery monomer 100.

[0337] In some embodiments, along the first direction, one side of the second insulating part 42 covers the first solder print 51, and the other side of the second insulating part 42 covers at least part of the first insulating part 41.

[0338] It can be understood that among the opposite two sides of the second insulating part 42 along the first direction, one side covers the first solder print 51, and the other side can cover the entire first insulating part 41, or a part of the first insulating part 41, or even the active material layer 20.

[0339] Along the first direction, the second insulating part 42 extends from the first solder print 51 to the first insulating part 41; or, the second insulating part 42 extends from the first solder print 51 to the active material layer 20, thereby completely covering the first insulating part 41.

[0340] By adopting the technical scheme of this embodiment, the second insulating part 42 and the first insulating part 41 jointly cover the extension part 122, which can realize double-layer insulation, help reduce the risk of short circuit of the battery monomer 100, and help improve the use reliability of the battery monomer 100.

[0341] In some embodiments, the electrode assembly 101 further comprises an insulating piece 40, the insulating piece 40 comprising a second insulating portion 42, at least part of the second insulating portion 42 covering the first welding mark 51.

[0342] It can be understood that the insulating piece 40 comprises the second insulating portion 42, the insulating piece 40 can not comprise the first insulating portion 41, or the insulating piece 40 can comprise the first insulating portion 41 and the second insulating portion 42.

[0343] By adopting the technical scheme of this embodiment, the second insulating portion 42 covers the surface of the first welding mark 51, which can block burrs, metal debris and other components on the surface of the first welding mark 51 from piercing the separator 3 and connecting with the second tab 2, thereby reducing the risk of short circuit of the battery monomer 100 and improving the use reliability of the battery monomer 100.

[0344] Please refer to FIGS. 18-21, in some embodiments, along the first direction, one side of the second insulating portion 42 covers the first welding mark 51, and the other side of the second insulating portion 42 covers at least part of the active material layer 20.

[0345] It can be understood that among the two sides of the second insulating portion 42 distributed along the first direction, one side covers the first welding mark 51, and the other side covers at least part of the active material layer 20, wherein the second insulating portion 42 can cover the end of the active material layer 20 towards the first connecting portion 31, or can cover the entire active material layer 20.

[0346] Along the first direction, the second insulating portion 42 extends from the first welding mark 51 to the active material layer 20, so that the metal layer 12 and the first connecting portion 31 are covered in the part between the first welding mark 51 and the active material layer 20. Among them, the first insulating portion 41 can be arranged between the second insulating portion 42 and the metal layer 12, or the first insulating portion 41 can not be arranged.

[0347] In some examples, the metal layer 12 is covered with the first insulating portion 41, and after the second insulating portion 42 completely covers the first insulating portion 41, the second insulating portion 42 can further extend to the active material layer 20 to cover the active material layer 20, so that the metal layer 12 is covered with the first insulating portion 41 and the second insulating portion 42, realizing two-layer insulation and good insulation effect.

[0348] In some examples, the metal layer 12 is not covered by the first insulating part 41, and the second insulating part 42 extends from the first welding mark 51 to the active material layer 20, so as to cover the part of the metal layer 12 between the first connecting part 31 and the active material layer 20, reduce the risk of short circuit of the part, and facilitate to improve the use reliability of the battery monomer 100. In addition, the first insulating part 41 can be omitted to save cost, and meanwhile, the active material layer 20 can be used to cover the position of the original first insulating part 41, so as to increase the coverage area of the active material layer 20 on the metal layer 12, and facilitate to improve the energy density of the battery monomer 100.

[0349] By adopting the technical scheme of the embodiment, the second insulating part 42 extends from the first welding mark 51 to the active material layer 20, the coverage area of the second insulating part 42 is wide, and the insulation effect is good, which facilitates to improve the use reliability of the battery monomer 100.

[0350] In some embodiments, the size of the part of the insulating part 40 covering the active material layer 20 in the first direction is H, where 0.2mm≤H≤1.0mm, and optionally, 0.3mm≤H≤0.8mm.

[0351] 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.

[0352] The design of H≥0.2mm enables the insulating part 40 to cover the end of the active material layer 20 towards the extension 122, and the insulating part 40 can block the burr at the end of the active material layer 20 towards the extension 122, thereby improving the use reliability of the battery monomer 100. The design of H≤1.0mm enables the part of the insulating part 40 covering the active material layer 20 not to be too large, which facilitates to reduce the weight and volume of the insulating part 40, and facilitates to improve the energy density of the battery monomer 100.

[0353] In some examples, the insulating part 40 comprises the first insulating part 41, and the first insulating part 41 covers the end of the active material layer 20 towards the extension 122. The part of the first insulating part 41 covering the active material layer 20 can be the mutual solubility region formed by the first insulating part 41 and the active material layer 20, so that the fixation of the first insulating part 41 is more stable.

[0354] In some examples, the insulating part 40 comprises the second insulating part 42, and the second insulating part 42 covers the end of the active material layer 20 towards the extension 122.

[0355] By adopting the technical solutions of the embodiment, along the first direction, the size of the part of the second insulating portion 42 covering the active material layer 20 is reasonable, and the problem of blocking the burrs at the end of the protruding portion 1222 of the conductive portion 121 and the energy density of the battery monomer 100 can be considered at the same time.

[0356] In some embodiments, 0.3mm≤H≤0.8mm.

[0357] By adopting the technical solutions of the embodiment, along the first direction, the size of the part of the second insulating portion 42 covering the active material layer 20 is more reasonable, and the problem of blocking the burrs at the end of the protruding portion 1222 of the conductive portion 121 and the energy density of the battery monomer 100 can be considered better.

[0358] In some embodiments, along the direction of the conductive portion 121 pointing to the protruding portion 1222, the second insulating portion 42 protrudes from the end face of the first protruding sub-portion 12221 facing away from the conductive portion 121.

[0359] Along the thickness direction of the current collector 10, the projection of the end face of the first protruding sub-portion 12221 facing away from the conductive portion 121 falls within the projection of the second insulating portion 42.

[0360] In the process of manufacturing the pole piece, the end face of the first protruding sub-portion 12221 facing away from the conductive portion 121 is obtained by cutting, which causes the end face of the first protruding sub-portion 12221 facing away from the conductive portion 121 to be prone to burrs. The second insulating portion 42 can block the burrs at the end face of the first protruding sub-portion 12221 facing away from the conductive portion 121, reduce the risk of short circuit inside the battery monomer 100, and be beneficial to improve the use reliability of the battery monomer 100. In addition, the second insulating portion 42 can completely cover the first solder sub-portion 5111, reduce the risk of short circuit caused by burrs, metal debris and other components on the first solder sub-portion 5111, and be beneficial to improve the use reliability of the battery monomer 100.

[0361] In some embodiments, along the direction of the conductive portion 121 pointing to the protruding portion 122, the second insulating portion 42 protrudes from the edge of the second solder sub-portion 5112 facing away from the first protruding sub-portion 12221.

[0362] Along the thickness direction of the current collector 10, the projection of the edge of the second solder sub-portion 5112 facing away from the first protruding sub-portion 12221 falls within the projection of the second insulating portion 42, so that the second insulating portion 42 can completely cover the second solder sub-portion 5112 and the first solder sub-portion 5111.

[0363] In the manufacturing process of the pole piece, the second insulating part 42 can completely cover the second solder sub-part 5112 and the first solder sub-part 5111, reduce the risk of short circuit caused by burrs, metal debris and other components on the second solder sub-part 5112 and the first solder sub-part 5111, and be beneficial to improve the use reliability of the battery monomer 100.

[0364] In some embodiments, the number of metal layers 12 is two, the two metal layers 12 are arranged on opposite sides of the insulating base 11 along the thickness direction of the current collector 10, the number of active material layers 20 is two, and the two active material layers 20 respectively cover the two metal layers 12; the number of conductive members 30 is two, the first connecting parts 31 of the two conductive members 30 are respectively welded to the surfaces of the two metal layers 12 away from the insulating base 11 and form two first solder marks 51; the number of insulating parts 40 is two, and the second insulating parts 42 of the two insulating parts 40 respectively cover at least part of the two first solder marks 51.

[0365] The number of metal layers 12, the number of insulating parts 40, the number of active material layers 20 and the number of conductive members 30 are all two, the two metal layers 12 respectively cover opposite sides of the insulating base 11 along the thickness direction, and the two active material layers 20 respectively cover the conductive parts 121 of the two metal layers 12; the first connecting part 31 of one conductive member 30 is welded to the surface of one of the metal layers 12 away from the insulating base 11 and forms a first solder mark 51, and the first connecting part 31 of the other conductive member 30 is welded to the other metal layer 12 to also form a first solder mark 51; the second insulating parts 42 of the two insulating parts 40 are located on opposite sides of the insulating base 11 along the thickness direction and respectively cover the two first solder marks 51.

[0366] By adopting the technical scheme of this embodiment, the first pole piece 1 is provided with two metal layers 12 and two active material layers 20, which is beneficial to improve the energy density of the battery monomer 100.

[0367] In some embodiments, in the direction of the conductive part 121 pointing to the extension part 122, the second insulating part 42 protrudes from the end of the transition part 1221 towards the protruding part 1222.

[0368] The direction of the conductive part 121 pointing to the extension part 122 can be referred to the direction indicated by the arrow Z in the figure.

[0369] Along the thickness direction of the current collector 10, the projection of the end surface of the transition part 1221 leading to the protruding part 1222 coincides with the projection of the second insulating part 42, so that the second insulating part 42 can cover the end surface of the transition part 1221 leading to the protruding part 1222.

[0370] During the process of cutting the conductive member 30, burrs are easily formed at the end surface of the transition portion 1221 toward the protruding portion 1222, especially, during the process of cutting the conductive member 30 at the first welding mark 51, larger burrs are easily formed at the end surface of the transition portion 1221 toward the protruding portion 1222; and the second insulating portion 42 of the embodiment of the present application can block the burrs at the end surface of the transition portion 1221 toward the protruding portion 1222 from piercing the separator 3 to contact the second tab 2, thereby reducing the risk of short circuit of the battery monomer 100, and is beneficial to improve the use reliability of the battery monomer 100.

[0371] In some embodiments, the second insulating portion 42 comprises a first portion 421 and a second portion 422 connected with each other, the first portion 421 covers at least part of the first welding mark 51, and the second portion 422 protrudes from the extending portion 122 in the direction of the conductive portion 121 toward the extending portion 122, and the second portion 422 is located at the side of the second connecting portion 32 in the second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0372] In some examples, the insulating member 40 is of an equal-width structure, and the insulating member 40 covers the conductive member 30 and the metal layer 12 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 portion 42 located within the projection range of the metal layer 12 and the conductive member 30 is the first portion 421, and the part of the second insulating portion 42 located outside the projection range of the metal layer 12 and the conductive member 30 is the second portion 422.

[0373] In some examples, during the process of cutting the conductive member 30, burrs are easily formed at the end surface of the transition portion 1221 toward the protruding portion 1222, especially, during the process of cutting the conductive member 30 at the first welding mark 51, larger burrs are easily formed at the end surface of the transition portion 1221 toward the protruding portion 1222; and the second portion 422 of the embodiment of the present application can block the burrs at the end surface of the transition portion 1221 toward the protruding portion 1222 from piercing the separator 3 to contact the second tab 2, thereby reducing the risk of short circuit of the battery monomer 100, and is beneficial to improve the use reliability of the battery monomer 100.

[0374] In some examples, the end surface of the transition portion 1221 toward the protruding portion 1222 is easily impacted to generate metal debris, and the metal debris is easily dropped into the electrode assembly 101, thereby causing short circuit of the battery monomer 100.

[0375] By adopting the technical scheme of the embodiment, in the direction of the conductive portion 121 toward the extending portion 122, the metal debris and other components at the end surface of the extending portion 122 away from the active material layer 20 can be located between the second portions 422 of the two insulating members 40, which can reduce the risk of metal debris dropping into the electrode assembly 101, and is beneficial to reduce the risk of short circuit.

[0376] In some embodiments, the second portions 422 of the two insulating pieces 40 are in abutment.

[0377] In some examples, the second portions 422 of the two insulating pieces 40 are located in the hollowed-out area of the protruding portion 1222 where the transition portion 1221 does not extend, so that the second portions 422 of the two insulating pieces 40 can be close to each other and thus in abutment.

[0378] The second portions 422 of the two insulating pieces 40 can be pasted or statically adsorbed together, and of course can also be other abutment modes.

[0379] By adopting the technical solutions of this embodiment, after the second portions 422 of the two insulating pieces 40 are in abutment, the extending portion 122 can cover the metal debris and other components at the end face of the active material layer 20, so that the metal debris 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.

[0380] In some embodiments, along the direction of the conductive portion 121 toward the extending portion 122, the second connecting portions 32 of the two conductive members 30 are welded and form second welding marks 52.

[0381] In some examples, along the direction of the conductive portion 121 toward the extending portion 122, the portions of the conductive members 30 protruding from the extending portion 122 form the second connecting portions 32, so that the second connecting portions 32 of the two conductive members 30 can be directly close to each other and thus welded together, and the traces left by welding are the second welding marks 52. The second connecting portions 32 of the two conductive members 30 can be welded by ultrasonic welding, laser welding, etc.

[0382] By adopting the technical solutions of this embodiment, the second connecting portions 32 of the two conductive members 30 can connect the metal layers 12 located on the opposite sides of the insulating matrix 11, thereby breaking the insulation limitation of the insulating matrix 11, effectively improving the conductive capacity of the first pole piece 1, improving the fast-charging performance of the battery monomer 100, reducing the heat generation of the battery monomer 100, and improving the use reliability of the battery monomer 100.

[0383] In some embodiments, the second insulating portion 42 covers the second welding mark 52, and along the direction of the conductive portion 121 toward the extending portion 122, the second insulating portion 42 protrudes from the edge of the second welding mark 52 away from the conductive portion 121.

[0384] Along the thickness direction of the current collector 10, the projection of the second welding mark 52 falls within the projection of the second insulating portion 42, so that the second insulating portion 42 can completely cover the second welding mark 52.

[0385] By adopting the technical scheme of the embodiment, the second insulating portion 42 can completely cover the second welding mark 52, and can block components such as a pointed protrusion and metal debris on the second welding mark 52 from piercing the separator 3 to be connected with the second tab 2, thereby reducing the risk of short circuit and improving the use reliability of the battery monomer 100.

[0386] In some embodiments, the electrode assembly 101 includes a second tab 2 opposite in polarity to the first tab 1, the second tab 2 including a main functional portion 210 and a tab portion 220, the tab portion 220 protruding from the main functional portion 210 in a first direction; in a direction of the conductive portion 121 toward the extension portion 122, the main functional portion 210 protrudes from the insulating member 40 toward an end surface of the active material layer 20, and the main functional portion 210 does not protrude from the insulating member 40 away from the end surface of the active material layer 20.

[0387] 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.

[0388] The second tab 2 includes 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 from 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, and the main functional portion 210 can include the part of the negative current collector except the protruding structure and the negative active material layer. 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, and the main functional portion 210 can include the part of the positive current collector except the protruding structure and the positive active material layer.

[0389] 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 on the end surface of the main functional portion 210 toward the tab portion 220.

[0390] 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.

[0391] By adopting the technical scheme of this embodiment, the insulating part 40 can block the burr at the end face of the main body functional part 210 of the second tab 2 close to the lug part 220 from piercing the isolation part 3 to connect with the first tab 1, reduce the risk of short circuit of the first tab 1 and the second tab 2, and be beneficial to improve the use reliability of the battery monomer 100.

[0392] In some embodiments, the electrode assembly 101 includes a second tab 2 opposite in polarity to the first tab 1, the second tab 2 including a main body functional part 210 and a lug part 220, the lug part 220 protruding from the main body functional part 210 in a first direction; in the direction of the conductive part 121 pointing to the extension part 122, the main body functional part 210 protrudes from the end face of the extension part 122 away from the conductive part 121.

[0393] 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 lug part 220 does not coincide with the projection of the metal layer 12, and the burr at the end face of the main body functional part 210 of the second tab 2 corresponds to the hollow area of the metal layer 12 not extending out of the second connecting part 32.

[0394] 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 insulating part 42, so that the second insulating part 42 can block the burr, metal debris and other components on the first welding mark 51 from piercing the isolation part 3 to connect with the second tab 2, reduce the risk of short circuit, and improve the use reliability of the battery monomer 100.

[0395] By adopting the technical scheme of this embodiment, the burr at the end face of the main body functional part 210 of the second tab 2 close to the lug part 220 corresponds to the hollow area of the metal layer 12 not extending out of the second connecting part 32, which can also reduce the risk of short circuit of the battery monomer 100 and improve the use reliability of the battery monomer 100.

[0396] In some embodiments, the current collector 10 further includes a conductive protective layer 13, at least part of the conductive protective layer 13 being located between the active material layer 20 and the conductive part 121.

[0397] The conductive protective layer 13 can refer to a conductive structure provided between the active material layer 20 and the conductive part 121, which can conduct electricity so that the battery monomer 100 can output or input electric energy. The conductive protective layer 13 can be an equal-thickness structure or a non-equal-thickness structure.

[0398] For example, part of the conductive protective layer 13 is located between the active material layer 20 and the conductive part 121, and the other part covers the transition part 1221 and protrudes out of the active material layer 20.

[0399] For example, the entire conductive protective layer 13 is located between the active material layer 20 and the conductive part 121.

[0400] In some examples, the conductive protective layer 13 can contain conductive carbon black and a binder, which can play a role in buffering and lubrication between the active material and the metal layer on the one hand, 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 conducive to improving the performance of the battery monomer 100.

[0401] During the rolling process of the first pole piece 1, the thickness of the metal layer 12 is thin, and the particles in the active material layer 20 can damage the metal layer 12, thereby causing the metal layer 12 to be prone to cracking and other problems. The conductive protective layer 13 of the embodiment of the present application can separate the active material layer 20 and the metal layer 12 while protecting the metal layer 12, reducing the risk of cracks in the metal layer 12 caused by rolling the active material layer 20, and is conducive to improving the current-carrying capacity of the metal layer 12.

[0402] In some embodiments, in the direction of the conductive part 121 pointing to the extension part 122, the conductive protective layer 13 protrudes from the active material layer 20 towards the end face of the protruding part 1222.

[0403] The conductive protective layer 13 protrudes from the active material layer 20, and the conductive protective layer 13 can completely separate the metal layer 12 and the active material layer 20, and in addition, it can provide an extension space for the active material layer 20 during the rolling process, which is conducive to the subsequent conductive protective layer 13 being able to completely separate the metal layer 12 and the active material layer 20.

[0404] By adopting the technical scheme of the embodiment, the conductive protective layer 13 can completely separate the active material layer 20 and the metal layer 12, the protective ability of the conductive protective layer 13 to the metal layer 12 is better, the current-carrying capacity of the first pole piece 1 is better, and the fast-charging performance and use reliability of the battery monomer 100 are improved.

[0405] In some embodiments, in the direction of the conductive part 121 pointing to the extension part 122, the protruding distance range of the conductive protective layer 13 protruding from the active material layer 20 towards the end face of the protruding part 1222 is 0.3mm-0.8mm.

[0406] The protruding distance of the conductive protective layer 13 protruding from the active material layer 20 towards the end face of the protruding part 1222 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.

[0407] The design of S3≥0.3mm can make the conductive protective layer 13 completely separate the active material layer 20 and the metal layer 12, the conductive protective layer 13 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 13 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.

[0408] By adopting the technical scheme of the embodiment, the overcurrent capacity and the energy density of the battery monomer 100 can be better balanced.

[0409] In some embodiments, the conductive protective layer 13 and the first welding mark 51 are spaced apart along the first direction.

[0410] In some examples, the conductive protective layer 13 is spaced apart from the first connecting part 31, and the first insulating part 41 covers the part of the conductive protective layer 13 between the first connecting part 31 and the active material layer 20.

[0411] By adopting the technical scheme of the embodiment, the first connecting part 31 will not be welded to the conductive protective layer 13, 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.

[0412] In some embodiments, the second insulating part 42 is connected with the first tab 1.

[0413] The second insulating part 42 can be connected with the metal layer 12, the conductive member 30 or the active material layer 20, wherein the second insulating part 42 can be connected on the first tab 1 by adhesion or pasting and the like.

[0414] By adopting the technical scheme of the embodiment, the second insulating part 42 is connected on the first tab 1, the second insulating part 42 can be fixed, so as to stably block the burr at the end of the protruding part 1222 towards the transition part 1221, which is beneficial to improve the use reliability of the battery monomer 100.

[0415] Please refer to FIG. 22 and FIG. 23, in some embodiments, the second insulating part 42 includes an insulating base layer 423 and an adhesive layer 424, the adhesive layer 424 is adhered between the insulating base layer 423 and the first tab 1.

[0416] The second insulation part 42 adopts the structure of a tape; the insulation base layer 423 can refer to the main body part of the second insulation part 42, and the adhesive layer 424 can refer to 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.

[0417] By adopting the technical solution of this embodiment, the structure of the tape is easy to cover comprehensively, which is conducive to reducing the risk of incomplete coverage and reducing the risk of internal short circuit of the battery monomer 100. The insulation base layer 423 can improve the structural strength of the second insulation part 42 and reduce deformation during the bonding process of the second insulation part 42, which is conducive to improving the insulation effect. The adhesive layer 424 can stably fix the insulation base layer 423 on the first pole piece 1 and reduce the risk of falling off of the insulation tape.

[0418] In some embodiments, the layer thickness of the insulation base layer 423 ranges from 6 μm to 15 μm.

[0419] The layer 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.

[0420] The design of T1≥6 μm makes the insulation base layer 423 have a certain thickness to block burrs and achieve insulation. The design of T1≤15 μm makes the thickness of the insulation base layer 423 not too large, which is conducive to reducing the volume occupied by the second insulation part 42 and improving the energy density of the battery monomer 100.

[0421] By adopting the technical solution of this embodiment, the internal insulation and energy density of the battery monomer 100 can be considered at the same time.

[0422] In some embodiments, the layer thickness of the adhesive layer 424 ranges from 0.5 μm to 3 μm.

[0423] The layer thickness of the adhesive layer 424 is T2, and 0.5 μm≤T2≤3 μm. It can be understood that the value of T2 can be 0.3 μm, 3 μm, and any value between 0.3 μm and 3 μm. For example, the value of T2 can be, but is not limited to, 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm.

[0424] The design of T2≥0.5 μm makes the bonding layer 424 have a certain thickness, so that the second insulating part 42 can be stably bonded on the first pole piece 1, and the second insulating part 42 has good insulation reliability; the design of T2≤3 μm 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.

[0425] By adopting the technical scheme of this embodiment, the insulation reliability and the energy density of the battery monomer 100 can be considered at the same time.

[0426] In some embodiments, the layer thickness of the insulating base layer 423 ranges from 6 μm to 15 μm; and the layer thickness of the bonding layer 424 ranges from 0.5 μm to 3 μm.

[0427] By adopting the technical scheme of this embodiment, the insulation reliability and the energy density of the battery monomer 100 can be considered at the same time.

[0428] In some embodiments, along the first direction, the size of the insulating piece 40 is W, where 3 mm≤W≤9 mm.

[0429] In some examples, the insulating piece 40 includes the second insulating part 42, and W is equal to the size of the second insulating part 42 along the first direction.

[0430] In some examples, the insulating piece 40 includes the second insulating part 42 and the first insulating part 41, and W is equal to the overall size of the second insulating part 42 and the insulating coating along the first direction.

[0431] 3 mm≤W≤9 mm. It can be understood that the value of W can be 3 mm, 9 mm, and any value between 3 mm and 9 mm. For example, the value of W can be, but is not limited to, 3 mm, 4 mm, 4.5 mm, 5 mm, 6 mm, 6.5 mm, 7 mm, 8 mm, and 9 mm.

[0432] The design of W≥3 mm makes the insulating piece 40 have a certain size along the first direction, which is conducive to the internal insulation of the battery monomer 100; and the design of W≤9 mm makes the size of the insulating piece 40 along the first direction not too large, which is conducive to reducing the volume occupied by the insulating piece 40 and improving the energy density of the battery monomer 100.

[0433] By adopting the technical scheme of this embodiment, the insulation reliability and the energy density of the battery monomer 100 can be considered at the same time.

[0434] In some embodiments, 4.5 mm≤W≤6.5 mm.

[0435] By adopting the technical scheme of the embodiment, the size of the insulating piece 40 is reasonable in the first direction, and the insulation reliability and the energy density of the battery monomer 100 can be well balanced.

[0436] In some embodiments, the thickness of the conductive part 121 is less than the thickness of the extension part 122 at least in part.

[0437] For example, the extension part 122 is an equal-thickness structure or a substantially equal-thickness structure, the conductive part 121 is also an equal-thickness structure or a substantially equal-thickness structure, and the thickness t1 of the extension part 122 is greater than the thickness of the conductive part 121.

[0438] For example, the conductive part 121 can be of unequal thickness, and the thickness of the conductive part 121 increases in the direction of the conductive part 121 pointing to the extension part 122, which can specifically be in a stepped increase or a slow increase. The thickness of the part of the conductive part 121 away from the transition part 1221 is less than the thickness of the transition part 1221.

[0439] By adopting the technical scheme of the embodiment, the thickness t1 of the extension part 122 is large, the flow capacity of the extension part 122 is good, which is conducive to improving the flow capacity of the first pole piece 1, reducing the heat generation of the battery monomer 100, and improving the fast-charging performance and use reliability of the battery monomer 100.

[0440] In some embodiments, the conductive part 121 includes a first sub-part 1211 and a second sub-part 1212, the first sub-part 1211 is connected between the second sub-part 1212 and the extension part 122, the first sub-part 1211 and the second sub-part 1212 are covered with the active material layer 20, the thickness of the first sub-part 1211 is greater than the thickness of the second sub-part 1212, and the thickness of the extension part 122 is greater than or equal to the thickness of the first sub-part 1211.

[0441] The conductive part 121 can be of unequal thickness, and the conductive part 121 is divided into two parts in the direction of the conductive part 121 pointing to the extension part 122. The part close to the extension part 122 is the first sub-part 1211, and the part away from the extension part 122 is the second sub-part 1212. The first sub-part 1211 and the second sub-part 1212 are both covered with the active material layer 20.

[0442] In some examples, the first sub-part 1211 can be an equal-thickness structure, and the second sub-part 1212 can be an equal-thickness structure; the thickness t2 of the first sub-part 1211 is greater than the thickness t3 of the second sub-part 1212, and the thickness t1 of the transition part 1221 is greater than or equal to the thickness t2 of the first sub-part 1211, so that the first sub-part 1211 and the second sub-part 1212 form a stepped structure; the thickness t1 of the transition part 1221 can be equal to the thickness t2 of the first sub-part 1211, so that the transition part 1221 and the first sub-part 1211 form an equal-thickness structure; or, the thickness t1 of the transition part 1221 can be greater than the thickness t3 of the second sub-part 1212, so that the first sub-part 1211 and the transition part 1221 form a stepped structure.

[0443] In some examples, the first sub-part 1211 can also be a multi-section structure, and the thickness of each section gradually increases in the direction of the conductive part 121 pointing to the extension part 122; for example, the first sub-part 1211 includes a first section and a second section, the first section is located between the second section and the second sub-part 1212, and the thickness of the first section gradually increases in the direction of the conductive part 121 pointing to the extension part 122, and the second section is generally an equal-thickness structure, and the thickness of the second section is equal to the thickness t1 of the transition part 1221; the thickness of the first section gradually increases from the thickness t3 of the second sub-part 1212 to the thickness of the second section, and the first section is arranged to smoothly connect the second section and the second sub-part 1212, which is beneficial to reduce stress concentration and improve structural strength. The thickness of the first section can be equal to the thickness t1 of the transition part 1221, and the thickness t1 of the transition part 1221 can also be greater than the thickness of the first section.

[0444] In the use process of the battery cell 100, the electrons and ions generated by the active material layer 20 gradually flow to the transition part 1221 through the conductive part 121 in the direction of the conductive part 121 pointing to the extension part 122, and the electrons and ions flowing through the part of the conductive part 121 close to the transition part 1221 are more than those flowing through the part of the conductive part 121 away from the transition part 1221, so the overcurrent capacity of the part of the conductive part 121 close to the transition part 1221 is required to be greater than that of the part of the conductive part 121 away from the transition part 1221.

[0445] The first sub-part 1211 of the embodiment of the application is connected between the second sub-part 1212 and the transition part 1221, and the thickness t2 of the first sub-part 1211 is greater than the thickness t3 of the second sub-part 1212, so that the overcurrent capacity of the first sub-part 1211 close to the transition part 1221 is greater than that of the second sub-part 1212 away from the transition part 1221, which can reduce the limitation on the current, improve the overcurrent capacity of the first electrode tab 1, reduce the heating of the battery cell, and be beneficial to improve the use reliability of the battery cell 100.

[0446] In some embodiments, the current collector 10 further comprises a conductive protective layer 13, the conductive protective layer 13 comprises a first protective part 131 and a second protective part 132, the first protective part 131 is located between the first sub-part 1211 and the active material layer 20, and the second protective part 132 is located between the second sub-part 1212 and the active material layer 20; wherein the thickness of the first protective part 131 is less than the thickness of the second protective part 132.

[0447] In some examples, along the first direction, the part of the conductive protective layer 13 between the first sub-part 1211 and the active material layer 20 can be the first protective part 131, and the part of the conductive protective layer 13 between the second sub-part 1212 and the active material layer 20 can be the second protective part 132, wherein the thickness t4 of the first protective part 131 is less than the thickness t5 of the second protective part 132, and the thickness t2 of the first sub-part 1211 is greater than the thickness t3 of the second sub-part 1212, which can reduce the difference between the thickness of the current collector 10 at the first protective part 131 and the thickness at the second protective part 132.

[0448] For example, the first sub-part 1211 is divided into a third part and a fourth part, the third part is located between the first section and the active material layer 20, the fourth part is located between the second section and the active material layer 20, the third part is located between the fourth part and the second protective part 132, along the direction of the conductive part 121 pointing to the extension part 122, the thickness of the third part gradually decreases, and the fourth part is generally an equal-thickness structure, so that the thickness t4 of the first protective part 131 can be adapted to the thickness t2 of the first sub-part 1211, and the surface of the conductive protective layer 13 away from the insulating substrate 11 is close to a plane.

[0449] By adopting the technical scheme of this embodiment, the surface of the conductive protective layer 13 away from the insulating substrate 11 is close to a plane, which is beneficial to reduce the roll damage and improve the current-carrying capacity of the metal layer 12; in addition, it can also reduce the winding bulging problem of the current collector 10.

[0450] In some embodiments, the conductive protective layer 13 further comprises a third protective part 133, the third protective part 133 covers the surface of the extension part 122 away from the insulating substrate 11, and the thickness of the third protective part 133 is less than or equal to the thickness of the first protective part 131.

[0451] In some examples, along the first direction, the conductive protective layer 13 can be divided into three parts, a part close to the conductive member 30 is a third protective part 133, a part far from the conductive member 30 is a second protective part 132, and a part in the middle is a first protective part 131, wherein the thickness t4 of the first protective part 131 is less than the thickness t5 of the second protective part 132, and the thickness t2 of the first sub-part 1211 is greater than the thickness t5 of the second protective part 132, so as to reduce the difference between the thickness of the current collector 10 at the first protective part 131 and the thickness of the current collector 10 at the second protective part 132; similarly, the thickness t6 of the third protective part 133 is less than or equal to the thickness t4 of the first protective part 131, and the thickness t1 of the transition part 1221 is greater than or equal to the thickness t2 of the first sub-part 1211, so as to reduce the difference between the thickness of the current collector 10 at the first protective part 131 and the thickness of the current collector 10 at the third protective part 133, and facilitate the surface of the conductive protective layer 13 opposite to the metal layer 12 to be close to a plane.

[0452] For example, the second protective part 132, the third protective part 133, the transition part 1221 and the second sub-part 1212 are all equal-thickness structures, and the first sub-part 1211 and the first protective part 131 are all unequal-thickness structures; the thickness t2 of the first sub-part 1211 and the thickness t4 of the first protective part 131 are matched with each other, so that the surface of the conductive protective layer 13 opposite to the insulating substrate 11 is close to a plane.

[0453] By adopting the technical aspect of this embodiment, the third protective part 133 is arranged, so that the conductive protective layer 13 protrudes from the active material layer 20, so that the active material layer 20 and the metal layer 12 can be better separated, in addition, the thickness of the third protective part 133 is not too large, which is beneficial to reduce the waste of materials and save the manufacturing cost of the battery monomer 100.

[0454] In some embodiments, the thickness t7 of the protruding part 1222 is greater than or equal to the thickness t1 of the transition part 1221.

[0455] For example, the thickness t7 of the protruding part 1222 can be equal to the thickness t1 of the transition part 1221, so that the protruding part 1222 and the transition part 1221 form an equal-thickness structure.

[0456] For example, the thickness t7 of the protruding part 1222 can be greater than the thickness t1 of the transition part 1221, so that the protruding part 1222 and the transition part 1221 form a stepped structure.

[0457] By adopting the technical solution of this embodiment, the thickness t7 of the protruding part 1222 is relatively thick, which can improve the flow capacity of the protruding part 1222, is beneficial to improve the flow capacity of the first pole piece 1, reduce the heating of the battery monomer 100, and is beneficial to improve the fast-charging performance and use reliability of the battery monomer 100.

[0458] In some embodiments, the second active material portion 22 has a thickness t8, where 0.002≤(t1-t3) / t8≤0.08.

[0459] t1-t3 can refer to the difference between the thickness of the transition portion 1221 and the second sub-portion 1212, to represent the thickening degree of the transition portion 1221.

[0460] The value of (t1-t3) / t8 can be 0.002, 0.08, and any value between 0.002 and 0.08; for example, the value of (t1-t3) / t8 can be, but is not limited to, 0.002, 0.003, 0.004, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08.

[0461] By adopting the technical solutions of this embodiment, the setting of 0.002≤(t1-t3) / t8≤0.08 makes the thickness difference between the transition portion 1221 and the second sub-portion 1212 be within the thickness error range of the active material layer 20, so that the thickening of the transition portion 1221 is less likely to cause the surface of the active material layer 20 to protrude, which can reduce subsequent roll damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, and is beneficial to improving the use reliability of the battery monomer 100.

[0462] In some embodiments, 0.003≤(t1-t3) / t8≤0.06.

[0463] By adopting the technical solutions of this embodiment, the setting of 0.003≤(t1-t3) / t8≤0.06 makes the thickness difference between the transition portion 1221 and the second sub-portion 1212 be better within the thickness difference range of the active material layer 20, so that the thickening of the transition portion 1221 is even less likely to cause the surface of the active material layer 20 to protrude, which can reduce subsequent roll damage and subsequent extrusion damage between the first pole piece 1 and other pole pieces, and is beneficial to improving the use reliability of the battery monomer 100.

[0464] In some embodiments, 60μm≤t8≤250μm.

[0465] It can be understood that the value of t8 can be 60μm, 250μm, and any value between 60μm and 250μm; for example, the value of t8 can be, but is not limited to, 60μm, 70μm, 80μm, 90μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, 250μm.

[0466] The design with t8≥60μm allows the battery cell 100 to have a higher capacity; the design with t3≤250μm ensures that the distance for electrons to escape from the part of the active material layer 20 close to the metal layer 12 is not too long, and the electrons in the part of the active material layer 20 close to the metal layer 12 are easy to escape, which is beneficial to improving the capacity of the battery cell 100.

[0467] By adopting the technical solution of this embodiment, the thickness of the second active material portion 22 is within a suitable range, and the volume of the active material layer 20 is reasonably set, which is beneficial to improving the fast charging performance and reliability of the battery cell 100. It can also reduce the risk of ion extraction difficulties in the region of the active material layer 20 near the conductive layer, thereby improving the performance of the battery cell 100.

[0468] In some embodiments, 80μm≤t8≤180μm.

[0469] By adopting the technical solution of this embodiment, with the setting of 80μm≤t8≤180μm, the thickness of the second active material part 22 is within a more suitable range, and the volume setting of the active material layer 20 is reasonable. This is beneficial to improving the fast charging performance and reliability of the battery cell 100, and can also reduce the risk of ion extraction difficulties in the region of the active material layer 20 near the conductive layer, thereby improving the performance of the battery cell 100.

[0470] In some embodiments, 0.2 μm ≤ t1 - t3 ≤ 4.5 μm.

[0471] 0.2μm≤t1-t3≤4.5μm. It can be understood that the value of t1-t3 can be 0.2μm, 4.5μm, or any value between 0.2μm and 4.5μm; for example, the value of t1-t3 can be, but is not limited to, 0.2μm, 0.3μm, 0.1μm, 0.5μm, 1μm, 1.5μm, 1.75μm, 2μm, 3μm, 4μm, and 4.5μm.

[0472] By adopting the technical solution of this embodiment, the design of 0.2μm≤t1-t3≤4.5μm makes the thickness of the transition portion 1221 reasonable. On the basis of improving the current carrying capacity, the thickness of the transition portion 1221 is not too large, which would occupy too much space and weight, which is conducive to improving the energy density of the battery cell 100.

[0473] In some embodiments, 0.3 μm ≤ t1 - t3 ≤ 1.75 μm.

[0474] By adopting the technical solution of this embodiment, the design of 0.3μm≤t1-t3≤1.75μm makes the thickness of the transition part 1221 more reasonable, the current carrying capacity better, and it is also more conducive to improving the energy density of the battery cell 100.

[0475] In some embodiments, 1 < t1 / t3 ≤ 4, optionally, 1.5 < t1 / t3 ≤ 2.5.

[0476] t1 / t3 can refer to the ratio of the thickness t1 of the transition portion 1221 to the thickness t3 of the second sub-portion 1212, and can also represent the thickening degree of the transition portion 1221.

[0477] 1 < t1 / t3 ≤ 4, it can be understood that the value of t1 / t3 can be 4 and any value between 1 and 4; for example, the value of t1 / t3 can be, but is not limited to, 1.1, 1.5, 2, 2.5, 3, 3.5, and 4.

[0478] By adopting the technical solution of this embodiment, the design of 1 < t1 / t3 ≤ 4 makes the thickening degree of the transition portion 1221 reasonable, which improves the flow capacity on the basis that the thickness of the transition portion 1221 is not too large to occupy a large space and weight, and is conducive to improving the energy density of the battery monomer 100.

[0479] In some embodiments, 1.5 < t1 / t3 ≤ 2.5.

[0480] By adopting the technical solution of this embodiment, the design of 1.5 < t1 / t3 ≤ 2.5 makes the thickening degree of the transition portion 1221 more reasonable, which is better for the flow capacity and is also more conducive to improving the energy density of the battery monomer 100.

[0481] In some embodiments, 1 μm ≤ t1 ≤ 5 μm.

[0482] 1 μm ≤ t1 ≤ 5 μm, it can be understood that the value of t1 can be 1 μm, 5 μm, and any value between 1 μm and 5 μm; for example, the value of t1 can be, but is not limited to, 1 μm, 1.1 μm, 1.2 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, and 5 μm.

[0483] By adopting the technical solution of this embodiment, the design of 1 μm ≤ t1 ≤ 5 μm makes the thickness design of the transition portion 1221 reasonable, which is conducive to improving the flow capacity, and in addition, the thickness of the transition portion 1221 is not too large to occupy a large space and weight, which is conducive to improving the energy density of the battery monomer 100.

[0484] In some embodiments, 1.2 μm ≤ t1 ≤ 3.5 μm.

[0485] By adopting the technical solution of this embodiment, the design of 1.2 μm ≤ t1 ≤ 3.5 μm makes the thickness design of the transition portion 1221 more reasonable, which is better for the flow capacity and is also more conducive to improving the energy density of the battery monomer 100.

[0486] In some embodiments, 0.03≤t6 / t5≤0.95.

[0487] t6 / t5 can refer to the ratio of the thickness of the third protective portion 133 to the thickness of the second protective portion 132, which can represent the thinning degree of the third protective portion 133 relative to the second protective portion 132.

[0488] 0.03≤t6 / t5≤0.95, it can be understood that the value of t6 / t5 can be 0.03, 0.95, and any value between 0.03 and 0.95; for example, the value of t6 / t5 can be, but is not limited to, 0.03, 0.1, 0.125, 0.15, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95.

[0489] By adopting the technical scheme of this embodiment, the design of 0.03≤t6 / t5≤0.95 makes the thinning degree of the conductive protective layer 13 reasonable, which can better adapt to the thickening degree of the transition portion 1221, is conducive to the surface of the conductive protective layer 13 facing away from the metal layer 12 being close to a plane, and is conducive to reducing roll damage and improving the flow capacity of the metal layer 12.

[0490] In some embodiments, 0.125≤t6 / t5≤0.8.

[0491] By adopting the technical scheme of this embodiment, the design of 0.03≤t6 / t5≤0.95 makes the thinning degree of the conductive protective layer 13 more reasonable, which can better adapt to the thickening degree of the transition portion 1221, is conducive to the surface of the conductive protective layer 13 facing away from the metal layer 12 being close to a plane, and is conducive to reducing roll damage and improving the flow capacity of the metal layer 12.

[0492] In some embodiments, 0.5μm≤t6≤4μm.

[0493] 0.5μm≤t6≤4μm, it can be understood that the value of t6 can be 0.5μm, 4μm, and any value between 0.5μm and 4μm; for example, the value of t6 can be, but is not limited to, 0.5μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 4μm, 5μm.

[0494] By adopting the technical scheme of this embodiment, the setting of 0.5μm≤t6≤4μm makes the third protective portion 133 have a certain thickness, thereby reducing the risk of cracking of the metal layer 12; in addition, the third protective portion 133 will not protrude from the second protective portion 132 due to being too thick, and the material accumulation can also be reduced, thereby reducing the production cost.

[0495] In some embodiments, 1μm≤t6≤2μm.

[0496] By adopting the technical solutions of this embodiment, the setting of 1 μm≤t6≤2 μm makes the third protection part 133 have a more reasonable thickness, thereby better reducing the risk of cracking of the metal layer 12 and the manufacturing cost.

[0497] In some embodiments, along the first direction, the size of the first sub-part 1211 is W1, and the size of the second sub-part 1212 is W2, where W1 / (W1+W2)≤0.45.

[0498] For example, the size W1 of the first sub-part 1211 can refer to the width of the first sub-part 1211, and the size W2 of the second sub-part 1212 can refer to the width of the second sub-part 1212. W1+W2 can refer to the width of the conductive part 121.

[0499] W1 / (W1+W2) can refer to the proportion of the first sub-part 1211 occupying the conductive part 121 in the width direction of the first pole piece 1.

[0500] W1 / (W1+W2)≤0.45 can be understood as that the value of W1 / (W1+W2) can be 0.45 and any value between 0 and 0.45; for example, the value of W1 / (W1+W2) can be, but is not limited to, 0.001, 0.1, 0.2, 0.3, 0.4, 0.45.

[0501] By adopting the technical solutions of this embodiment, the design of W1 / (W1+W2)≤0.45 makes the active material layer 20 cover the first sub-part 1211, so as to improve the overcurrent capacity and reduce the heat generation of the battery monomer 100; in addition, along the second direction, the first sub-part 1211 does not occupy too much area, which is conducive to reducing the occupied space and weight of the first sub-part 1211 and improving the energy density of the battery monomer 100.

[0502] In some embodiments, along the first direction, the size of the first sub-part 1211 is W2, where 10 mm≤W2≤100 mm.

[0503] It can be understood that the value of W2 can be 10 mm, 100 mm, and any value between 10 mm and 100 mm; for example, the value of W2 can be, but is not limited to, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, and 100 mm.

[0504] By adopting the technical scheme of the embodiment, the design of 10mm≤W2≤100mm makes the active material layer 20 cover the first sub portion 1211, so as to improve the flow capacity and reduce the heat production of the battery monomer 100; in addition, along the second direction, the first sub portion 1211 does not occupy a large area, which is beneficial to reduce the occupied space and weight of the first sub portion 1211 and improve the energy density of the battery monomer 100.

[0505] The battery monomer 100 of the present application will be described below in combination with some embodiments.

[0506] Embodiment one

[0507] Referring to FIGS. 3-10, in the present embodiment, the battery monomer 100 comprises 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 end cover 201 is provided with an electrode lead-out portion 2011.

[0508] In the present embodiment, the electrode assembly 101 comprises 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, wherein the first electrode sheet 1 can be a positive electrode sheet and the second electrode sheet 2 can be a negative electrode sheet.

[0509] In the present embodiment, the first electrode sheet 1 comprises a current collector 10, an active material layer 20 and a conductive member 30, the current collector 10 comprises an insulating base body 11, a metal layer 12 and a conductive protective layer 13, the metal layer 12 covers the opposite surfaces of the insulating base body 11 along the thickness direction, the surface of the metal layer 12 away from the insulating base body is covered with the conductive protective layer 13, and the surface of the conductive protective layer 13 away from the insulating base body is covered with the active material layer 20.

[0510] In the present embodiment, the two metal layers 12 are both welded with the conductive member 30, the conductive member 30 comprises a first connecting portion 31 and a second connecting portion 32 connected with each other, the first connecting portion 31 is welded with the metal layer 12 to form a first welding mark 51, and the second connecting portions 32 of the two conductive members 30 are welded to form a second welding mark 52.

[0511] In the present embodiment, the electrode assembly 101 further comprises an insulating member 40, the insulating member 40 comprises a first insulating portion 41, and the first insulating portion 41 is located between the first connecting portion 31 and the active material layer 20.

[0512] In the present embodiment, the metal layer 12 includes a conductive portion 121 and an extension portion 122, the extension portion 122 includes a transition portion 1221 and at least one protrusion portion 1222, the transition portion 1221 is connected between the conductive portion 121 and the transition portion 1221, the protrusion portion 1222 protrudes from the transition portion 1221 in a first direction, the active material layer 20 covers the conductive portion 121, the protrusion portion 1222 and the transition portion 1221 are not covered by the active material layer 20, and the first direction is perpendicular to a thickness direction of the current collector 10.

[0513] In the present embodiment, the number of the protrusion portions 1222 is plural, and the plural protrusion portions 1222 are arranged at intervals in a second direction, and the second direction is perpendicular to the first direction and the thickness direction of the current collector 10.

[0514] In the present embodiment, the protrusion portion 1222 includes a first protrusion sub-portion 12221 and a second protrusion sub-portion 12222, the first protrusion sub-portion 12221 is connected between the second protrusion sub-portion 12222 and the transition portion, the size of the second protrusion sub-portion 12222 in the second direction is smaller than the size of the first protrusion sub-portion 12221 in the second direction, the first protrusion sub-portion 12221 is welded with the first connecting portion 31 to form a first welding sub-portion 5111, the second protrusion sub-portion 12222 is welded with the first connecting portion 31 to form a second welding sub-portion 512, and the first welding sub-portion 5111 and the second welding sub-portion 5112 form the first welding 51.

[0515] The interval between the first welding 51 and the active material layer 20 ranges from 0.3 mm to 5 mm.

[0516] Embodiment Two

[0517] Referring to FIGS. 11-17, the present embodiment is different from the first embodiment in that the first connecting portion 31 is welded with the protrusion portion 1222 to form a first welding portion 511, the first connecting portion 31 is welded with the transition portion 1221 to form a second welding portion 512, and the first welding portion 511 and the second welding portion 512 form the first welding 51.

[0518] The insulating member 40 further includes a second insulating portion 42, one side of the second insulating portion 42 covers the first welding 51 and the second welding 52, and the other side of the second insulating portion 42 covers the first insulating portion 41.

[0519] In the present embodiment, the protrusion portion 1222 is welded with the first connecting portion 31 to form a first welding portion 511, the transition portion 1221 is welded with the first connecting portion 31 to form a second welding portion 512, and the first welding portion 511 and the second welding portion 512 form the first welding 51.

[0520] Embodiment Three

[0521] Referring to Figs. 18-21, the embodiment differs from the second embodiment in that, referring to Figs. 14-17, the insulating member 40 includes the second insulating portion 42 but does not include the first insulating portion 41, 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 active material layer 20.

[0522] In some embodiments, referring to Fig. 2, a battery device 1100 is provided, which includes the battery cell 100 of the above-described embodiments.

[0523] The battery device 1100 of the embodiments of the present application adopts the battery cell 100 described above, and the energy density of the battery device 1100 is large.

[0524] In some embodiments, referring to Fig. 1, an electric device is provided, which includes the battery device 1100 of the above-described embodiments.

[0525] The electric device of the embodiments of the present application adopts the battery device 1100 described above, and the energy density of the battery cell 100 is large, which is conducive to improving the endurance and use performance of the electric device.

[0526] 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 described here.

[0527] Finally, it should be noted 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 foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing 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

1. A battery cell, wherein, The application relates to a battery electrode assembly. The battery electrode assembly comprises: a housing provided with an electrode lead-out portion; an electrode assembly at least partially accommodated in the housing, the electrode assembly comprising a first electrode tab, the first electrode tab comprising a conductive member, a current collector and an active material layer, the conductive member being connected to the electrode lead-out portion; the current collector comprising an insulating base body and a metal layer, the insulating base body, the metal layer and the active material layer being stacked along the thickness direction of the current collector, at least part of the metal layer being located between the insulating base body and the active material layer; the metal layer comprises a conductive portion and an extension portion extending outward from the end of the conductive portion in a first direction, the first direction being perpendicular to the thickness direction of the current collector; the conductive portion is covered with the active material layer, and the extension portion is not covered with the active material layer; 2. The battery cell of claim 1, wherein: the conductive member is welded to the surface of the extension portion away from the insulating base body and forms a first welding mark, and the spacing between the first welding mark and the active material layer ranges from 0.3 mm to 5 mm.

3. The battery cell of claim 1 or 2, wherein: The spacing between the first welding mark and the active material layer ranges from 0.5 mm to 2.8 mm.

4. The battery cell of claim 3, wherein: The conductive member comprises a first connecting portion and at least one second connecting portion, the first connecting portion and the second connecting portion are arranged along the first direction, the first connecting portion and the second connecting portion are connected, the second connecting portion is connected to the electrode lead-out portion, the first connecting portion is welded to the surface of the extension portion away from the insulating base body and forms the first welding mark, and the second connecting portion is located on the side of the extension portion away from the conductive portion.

5. The battery cell of claim 4, wherein: In the first direction, the end surface of the first welding mark and the first connecting portion away from the active material layer are spaced apart.

6. The battery cell of any one of claims 3-5, wherein: In the first direction, the spacing between the end surface of the first welding mark and the first connecting portion away from the active material layer ranges from 0.3 mm to 1.2 mm. The first welding mark comprises a first welding mark portion, the extension portion comprises at least one protruding portion, the protruding portion is connected to the conductive portion, the first connecting portion is welded to the surface of the protruding portion away from the insulating base body and forms the first welding mark portion; 7. The battery cell of claim 6, wherein: In a second direction, the size of the protruding portion is smaller than the size of the conductive portion, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

8. The battery cell of claim 6 or 7, wherein: In the second direction, the first welding mark portion extends from one side edge of the protruding portion to the other side edge of the protruding portion. The protruding portion comprises a first protruding sub-portion and a second protruding sub-portion, the second protruding sub-portion is connected between the conductive portion and the first protruding sub-portion; In the second direction, the size of the second protruding sub-portion is smaller than the size of the first protruding sub-portion, and the size of the first protruding sub-portion is smaller than the size of the conductive portion; 9. The battery cell of claim 8, wherein: The first welding mark portion comprises a first welding sub-portion; the first connecting portion is welded to the surface of the first protruding sub-portion away from the insulating base body and forms the first welding sub-portion. In the second direction, the first welding sub-portion extends from one side edge of the first protruding sub-portion to the other side edge of the first protruding sub-portion.

10. The battery cell of claim 8 or 9, wherein: The first welding part further comprises a second welding sub-part, and the first connecting part is welded to a surface of the second protruding sub-part away from the insulating base and forms the second welding sub-part.

11. The battery cell of claim 10, wherein: In the second direction, the second welding sub-part extends from one side of the second protruding sub-part to the other side of the second protruding sub-part.

12. The battery cell of any one of claims 6-11, wherein: The number of the protruding parts is multiple, and the multiple protruding parts are arranged at intervals in the second direction, each of the protruding parts is welded to the first connecting part, and the second direction is perpendicular to the first direction and the thickness direction of the current collector.

13. The battery cell of claim 12, wherein: The first connecting part comprises multiple first connecting sub-parts arranged at intervals in the second direction, and the number of the second connecting parts is multiple, each of the first connecting sub-parts is connected to each of the second connecting parts one by one. Each of the first connecting sub-parts is welded to each of the protruding parts away from the surface of the insulating base.

14. The battery cell of any one of claims 6-13, wherein: The first welding part comprises a second welding part, the extending part further comprises a transition part connected between the protruding part and the conductive part, the first connecting part is welded to a surface of the transition part away from the insulating base and forms the second welding part. In the second direction, the size of the transition part is greater than the sum of the sizes of all the protruding parts.

15. The battery cell of claim 14, wherein: In the second direction, the size of the conductive part is L1, the size of the transition part is L2, and 0.8≤L2 / L1≤1.

16. The battery cell of claim 14 or 15, wherein: In the second direction, the size of the transition part is L2, the size of the second welding part is L3, and 0.8≤L3 / L2≤1.

17. The battery cell of any one of claims 14-16, wherein: The number of the protruding parts is multiple, and the multiple protruding parts are arranged at intervals in the second direction. The first connecting part comprises a second connecting sub-part and multiple first connecting sub-parts arranged at intervals in the second direction, and each of the first connecting sub-parts is welded to each of the protruding parts away from the surface of the insulating base. The number of the second connecting parts is multiple, and in the first direction, one side of each of the first connecting sub-parts is connected to each of the second connecting parts one by one, and the other side of each of the first connecting sub-parts is connected to the second connecting sub-part, and the second connecting sub-part is arranged continuously in the second direction. The second connecting sub-part is welded to a surface of the transition part away from the insulating base.

18. The battery cell of any one of claims 3-17, wherein: In the first direction, the first connecting part and the active material layer are arranged at intervals.

19. The battery cell of any one of claims 3-18, wherein: The electrode assembly further comprises an insulating member, the insulating member comprises a first insulating part, the first insulating part covers a surface of the extending part away from the insulating base, and the entire first insulating part is located between the first welding part and the active material layer.

20. The battery cell of claim 19, wherein: The first insulating part is located between the first connecting part and the active material layer.

21. The battery cell of claim 20, wherein: The insulating member further comprises a second insulating part, at least part of the second insulating part covers the first welding part.

22. The battery cell of claim 21, wherein: In the first direction, one side of the second insulating part covers the first welding part, and the other side of the second insulating part covers at least part of the first insulating part.

23. The battery cell of any one of claims 3-22, wherein: The electrode assembly further comprises an insulating member, the insulating member comprises a second insulating portion, at least part of the second insulating portion covers the first welding mark.

24. The battery cell of claim 23, wherein: Along the first direction, one side of the second insulating portion covers the first welding mark, and the other side of the second insulating portion covers at least part of the active material layer.

25. The battery cell of any one of claims 21-24, wherein: The number of the metal layers is two, the two metal layers are arranged on opposite sides of the insulating substrate along the thickness direction of the current collector, and the number of the active material layers is two, the two active material layers respectively cover the two metal layers. The number of the conductive members is two, the first connecting portions of the two conductive members are respectively welded to the surfaces of the two metal layers away from the insulating substrate and form the two first welding marks. The number of the insulating members is two, the second insulating portions of the two insulating members respectively cover at least part of the two first welding marks.

26. The battery cell of claim 25, wherein: The second insulating portion comprises a first portion and a second portion connected with each other, the first portion covers at least part of the first welding mark, along the direction of the conductive portion towards the extension portion, the second portion protrudes from the extension portion, and the second portion is located on the side of the second connecting portion along the second direction, wherein the second direction is perpendicular to the first direction and the thickness direction of the current collector.

27. The battery cell of claim 26, wherein: The second portions of the two insulating members are in close contact.

28. The battery cell of any one of claims 25-27, wherein: The second connecting portions of the two conductive members are welded and form a second welding mark.

29. The battery cell of claim 28, wherein: The second insulating portion covers the second welding mark, and along the direction of the conductive portion pointing to the extension portion, the second insulating portion protrudes from the edge of the second welding mark away from the conductive portion.

30. The battery cell of any one of claims 19-29, 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, and the tab portion protrudes from the main functional portion along the first direction. Along the direction of the conductive portion towards the extension portion, the main functional portion protrudes from the end face of the insulating member towards the active material layer, and the main functional portion does not protrude from the end face of the insulating member away from the active material layer.

31. The battery cell of any one of claims 1-30, 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, and the tab portion protrudes from the main functional portion along the first direction. Along the direction of the conductive portion pointing to the extension portion, the main functional portion protrudes from the end face of the extension portion away from the conductive portion.

32. The battery cell of any one of claims 1-31, wherein: The current collector further comprises a conductive protective layer, at least part of the conductive protective layer is located between the active material layer and the conductive portion.

33. The battery cell of claim 32, wherein: Along the direction of the conductive portion towards the extension portion, the conductive protective layer protrudes from the end face of the active material layer close to the extension portion.

34. The battery cell of claim 33, wherein: Along the direction of the conductive portion towards the extension portion, the protruding distance range of the conductive protective layer from the end face of the active material layer towards the extension portion is 0.3mm-0.8mm.

35. The battery cell of any one of claims 31-34, wherein: Along the first direction, the conductive protective layer and the first welding mark are arranged at intervals.

36. The battery cell of any one of claims 1-35, wherein: At least part of the thickness of the conductive portion is smaller than the thickness of the extension portion.

37. The battery cell of claim 36, wherein: The conductive portion includes a first sub-portion and a second sub-portion, the first sub-portion is connected between the second sub-portion and the extension portion, the first sub-portion and the second sub-portion are covered with the active material layer, the thickness of the first sub-portion is greater than the thickness of the second sub-portion, and the thickness of the extension portion is greater than or equal to the thickness of the first sub-portion.

38. The battery cell of claim 37, wherein: The current collector further includes a conductive protective layer, the conductive protective layer includes a first protective portion and a second protective portion, the first protective portion is located between the first sub-portion and the active material layer, and the second protective portion is located between the second sub-portion and the active material layer; wherein the thickness of the first protective portion is less than the thickness of the second protective portion.

39. The battery cell of claim 38, wherein: The conductive protective layer further includes a third protective portion, the third protective portion covers the surface of the extension portion away from the insulating base body, and the thickness of the third protective portion is less than or equal to the thickness of the first protective portion.

40. A battery device, wherein: The battery cell includes any one of claims 1-39.

41. An electrical device, comprising: The battery device includes claim 40.

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